Fix some CMEs and black screens seen during boot/splash. Should be minimal overhead after splash. (#1959)

Co-authored-by: Jason Mitchell <[email protected]>

.github/ISSUE_TEMPLATE/000-report-bug.yml

@@ -39,6 +39,7 @@ body:
         - Java 19
         - Java 20
         - Java 21
+        - Java 25
         - Other (Please Specify)
     validations:
       required: true

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,14 @@
+# Description of your *PR* and other info
+<!-- Please include a summary of the change -->
+<!-- Any details that you think are important to review this PR? -->
+<!-- Are there any Issues / PRs related to this one? -->
+
+<!-- Add a screenshot or a video demonstration for new features -->
+
+<details open><summary>Template</summary> <!-- OPEN is intentional -->
+
+### Before submitting a *pull request* make sure you have:
+- [ ] Read the [AI Contribution Policy](https://github.com/GTNewHorizons/Angelica/blob/master/AI_POLICY.md)
+- [ ] At least [skimmed](https://github.com/GTNewHorizons/Angelica/search?q=is%3Apr&type=Issues) the tracker for similar pull requests
+
+</details>

.github/scripts/announce-release.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+: "${REPO:?REPO required}"
+: "${TAG:?TAG required}"
+
+if [ -z "${DISCORD_WEBHOOK_URL:-}" ]; then
+  echo "DISCORD_WEBHOOK_URL not set, skipping"
+  exit 0
+fi
+
+if ! release_json=$(gh release view "$TAG" --repo "$REPO" --json body,url,publishedAt 2>&1); then
+  echo "Could not read release $TAG in $REPO; skipping:"
+  printf '%s\n' "$release_json"
+  exit 0
+fi
+body=$(jq -r '.body // ""' <<<"$release_json")
+url=$(jq -r '.url' <<<"$release_json")
+ts=$(jq -r '.publishedAt // ""' <<<"$release_json")
+[ -n "$ts" ] || ts=$(date -u +%Y-%m-%dT%H:%M:%SZ)
+
+payload=$(jq -n \
+  --arg title "$TAG" \
+  --arg url "$url" \
+  --arg desc "$body" \
+  --arg ts "$ts" \
+  '{
+    embeds: [{
+      title: ("Angelica " + $title + " released"),
+      url: $url,
+      description: (if ($desc | length) > 3900
+                    then $desc[0:3900] + "\n\n...[full changelog](" + $url + ")"
+                    else $desc end),
+      color: 3066993,
+      footer: { text: "GitHub Releases" },
+      timestamp: $ts
+    }]
+  }')
+
+curl -fsS -X POST -H "Content-Type: application/json" -d "$payload" "$DISCORD_WEBHOOK_URL"

.github/workflows/release-tags.yml

@@ -12,3 +12,22 @@ jobs:
   release-tags:
     uses: GTNewHorizons/GTNH-Actions-Workflows/.github/workflows/release-tags.yml@master
     secrets: inherit
+
+  notify-discord:
+    needs: [release-tags]
+    runs-on: ubuntu-24.04
+    if: >-
+      ${{ !endsWith(github.ref_name, '-snapshot')
+          && !contains(github.event.head_commit.message, '[snapshot]')
+          && !endsWith(github.ref_name, '-pre') }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+      - name: Announce release to Discord
+        shell: bash
+        env:
+          DISCORD_WEBHOOK_URL: ${{ secrets.DISCORD_RELEASE_WEBHOOK_URL }}
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          REPO: ${{ github.repository }}
+          TAG: ${{ github.ref_name }}
+        run: bash .github/scripts/announce-release.sh

.gitignore

@@ -3,8 +3,8 @@
 /.idea/
 /.vs/
 /.vscode/
-/run/
-/build/
+run/
+build/
 /eclipse/
 .classpath
 .project
@@ -12,6 +12,7 @@
 /config/
 /crash-reports/
 /logs/
+tmp/
 options.txt
 /saves/
 usernamecache.json
@@ -36,3 +37,4 @@ addon.local.gradle
 addon.local.gradle.kts
 addon.late.local.gradle
 addon.late.local.gradle.kts
+local/

AI_POLICY.md

@@ -0,0 +1,55 @@
+# AI Usage Policy
+
+This project has strict rules for AI usage:
+
+* **The human-in-the-loop must fully understand all code.** If you
+can't explain what your changes do and how they interact with the
+greater system without the aid of AI tools, do not contribute
+those changes.
+
+* **Issues and discussions can use AI assistance but must have a full
+human-in-the-loop.** This means that any content generated with AI
+must have been reviewed *and edited* by a human before submission.
+The author must do their research and trim this down.
+
+* **No AI-generated media is allowed (textures, videos, audio, etc.).**
+Text and code are the only acceptable AI-generated content, per the
+other rules in this policy.
+
+* **Commit messages, PR descriptions must read in your own voice.**
+No AI-authored or AI co-authored commits, including Co-authored-by AI tags.
+
+* **Only contribute fixes for bugs you have personally hit in-game.**
+If you haven’t experienced or reproduced a bug firsthand, and don’t
+already know the relevant code well, don’t throw AI at it and forward it to us.
+Patches written for problems the author never actually experienced themselves
+tend to fix the wrong thing and/or produce another.
+
+* **The voice and intent of written content must be yours.**
+For documentation and especially quests, the tone and the point you're trying to make
+has to come from you, not an AI. Use AI to help with phrasing or cleanup if you like,
+but if the substance and voice aren't yours, don't contribute it.
+
+* **Bad AI use may be blocked.** People who produce bad contributions
+that are clearly AI (slop) may be blocked from making future contributions.
+We love to help junior developers learn and grow, but if you're interested
+in that, don't use AI and we'll help you. We're sorry that bad AI
+users have ruined this for you.
+
+
+## There are Humans Here
+
+Please remember that this project is maintained by humans.
+
+Every discussion, issue, and pull request is read and reviewed by
+humans (and sometimes machines, too). It is a boundary point at which
+people interact with each other and work is done. It is rude and
+disrespectful to approach this boundary with low-effort, unqualified
+work, since it puts the burden of validation on the maintainer.
+
+In a perfect world, AI would produce high-quality, accurate work
+every time. But today, that reality depends on the user of the AI.
+And today, many users of AI do not use it well. So, until that
+changes, we need to have strict rules to protect maintainers.
+
+Based on https://github.com/ghostty-org/ghostty/blob/main/AI_POLICY.md

README.MD

@@ -7,40 +7,50 @@
 * It's a cute angle -mitchej123
 * It's the angel that pulls you out of OptiFine's hell -Roadhog360
 
-## **Beta Quality - Here there be Dragons** 
-* Shaders sneak preview - Please don't report issues yet, but please do submit fixes
-   * Complementary & BSL mostly function, but have some bugs
-   * Sildurs, Seus, and any other shader probably doesn't work
+## **Beta Quality - Here there be Dragons**
+* Shaders - Beta
+   * Complementary + Euphoria Patches is the primary compatibility target
+   * Sildurs, Seus, and any other shaders might work
+
+## Core Profile
+Targets GL 3.3+ core profile
+* FFP emulation via generated GLSL shaders
+* Display list emulation
+* Software matrix stacks and state management through GLSM
+* GL_QUADS → GL_TRIANGLES conversion
+* Automatic transformation of mod shaders that use compat-only GLSL builtins (`gl_ModelViewMatrix`, `texture2D`, etc.)
 
 
 # Required Dependencies
-* [UniMixins](https://github.com/LegacyModdingMC/UniMixins/releases) >= 0.1.14
-* [GTNHLib](https://github.com/GTNewHorizons/GTNHLib/releases) >= 0.4.2
+* [UniMixins](https://github.com/LegacyModdingMC/UniMixins/releases) >= 0.1.23
+* [GTNHLib](https://github.com/GTNewHorizons/GTNHLib/releases) >= 0.11.19
 * NOTE: Some mods are not required, but a specific version is required if present - see: `Permanent Incompatibilities` below.
 
 # Known (temporary) Incompatibilities
 * Forge Relocation - Currently non Thread Safe; safe if not in use
-* ProjectRed Frames - Currently non Thread Safe; safe if not in use'
+* ProjectRed Frames - Currently non Thread Safe; safe if not in use
 
 # Potential Incompatibilities
 * EndlessIDs - Compat commits have been made, might work, might not - not fully tested
 
 # Known Incompatibilities
 * FalseTweaks - Not currently planned (Looking for volunteers) [Might work if you effectively disable most of the mod]
-* SmoothFont - Not currently planned (Looking for volunteers)
 * RPLE - Not currently planned (Looking for volunteers)
+* LiteLoader - Install [LiteloaderLoader](https://github.com/Midnight145/LiteloaderLoader)
 
 # Permanent Incompatibilities
 * OptiFine [Disabled, won't fix]
 * FastCraft [Disabled, won't fix]
 * BetterFPS [Disabled, won't fix]
 * OptimizationsAndTweaks [Disabled, won't fix]
-* [Amazing Trophies 1.2.1 and below](https://github.com/GTNewHorizons/Amazing-Trophies/releases) - use 1.2.2+
+* [Amazing Trophies 1.2.1 and below](https://github.com/GTNewHorizons/Amazing-Trophies/releases) - Use 1.2.2+
 * [LWJGL3ify 1.5.4 and below](https://github.com/GTNewHorizons/lwjgl3ify/releases/) - Use the latest version available, 1.5.7+
 * [ArchaicFix 0.6.2 and below](https://www.curseforge.com/minecraft/mc-mods/archaicfix/files/all?page=1&pageSize=20) - Use 0.7.0 or above
-* [Hodgepodge 2.4.3 and below](https://github.com/GTNewHorizons/Hodgepodge/releases) - Use 0.4.5 or above
+* [Hodgepodge 2.4.3 and below](https://github.com/GTNewHorizons/Hodgepodge/releases) - Use 2.4.5 or above
 * CodeChicken[Core](https://github.com/GTNewHorizons/CodeChickenCore/releases)/[Lib](https://github.com/GTNewHorizons/CodeChickenLib/releases) <1.2.0 - Threading issues, use 1.3.0+
 * Neodymium - Untested, but unlikely to be compatible. (Chunk Meshing is definitely incompatible, other features might work depending on config)
+* SmoothFont - Equivalent functionality added
+* ClientFixer - Use a resource pack like [GTNH-FTI-Standard-Font](https://github.com/Eldrinn-Elantey/GTNH-FTI-Standard-Font)
 
 # Credits
 * ShadersMod
@@ -55,16 +65,16 @@
   * The [Iris](https://github.com/IrisShaders/Iris) Team: coderbot, IMS212, Justsnoopy30, FoundationGames
   * Asek3 for the Iris Forge port [Oculus](https://github.com/Asek3/Oculus/tree/839ce8eca8cf0c4f6b7a1322b906e5c99125ca69)
   * Backported code under the LGPL
-* Sodium
+* Sodium / Celeritas
   * JellySquid & the CaffeineMC team, for making Sodium in the first place
-  * Embeddedt for [Embeddium](https://github.com/embeddedt/embeddium/tree/dc59ca357c25beefd6288f0d1d40b4cd8e670ab8) under the [LGPL 3.0](https://github.com/embeddedt/embeddium/blob/16.x/forge/LICENSE)
+  * Embeddedt for Celeritas used under the LGPL 3.0
 * Reese's Sodium Options
   * FlashyReese for [Reese's Sodium Options](https://github.com/FlashyReese/reeses-sodium-options/tree/aa4ea67047cf53e54976e93c6bb1ab5ba16b142b) under the [MIT license](https://github.com/FlashyReese/reeses-sodium-options/blob/aa4ea67047cf53e54976e93c6bb1ab5ba16b142b/LICENSE.txt)
 * Neodymium
   * Makamys for [Neodymium](https://github.com/makamys/Neodymium) - Various Tessellator -> Quad functionality taken under the LGPL 3
 * MCPatcherForge
   * Original [MCPatcher](https://bitbucket.org/prupe/mcpatcher/src/master/): Paul Rupe
-  * [Forge version](https://bitbucket.org/prupe/mcpatcher/src/master/): Mist475 under LGPL 3.0 with default ctm textures for glass and bookshelves by DarkBum under CC-BY-SA
+  * [Forge version](https://github.com/mist475/MCPatcherForge): Mist475 under LGPL 3.0 with default ctm textures for glass and bookshelves by DarkBum under CC-BY-SA
 * HUDCaching
   * Created by [Moulberry](https://github.com/Moulberry/MCHUDCaching), backported from [Patcher](https://github.com/Sk1erLLC/Patcher) mod by Alexdoru under the CC-BY-SA-NC 4.0 license
 * Angelica
@@ -82,3 +92,10 @@
   * Code from both glsl-transformation-lib and Monocle taken under their respective LGPL 3.0 licenses
 * FalseTweaks
   * FalsePattern for [FalseTweaks](https://github.com/falsepattern/falsetweaks) - Item Rendering Optimizations taken from FalseTweaks under the LGPL 3.0 license
+* Beddium
+  * Venn and Falsepattern for [Beddium](https://github.com/vfx-dev/Beddium) - MinimapRenderer, SafeChunkTracker, and some debug commands adapted under the LGPL 3.0 License
+* [Mesa](https://gitlab.freedesktop.org/mesa/mesa) — Code ported and/or inspired from Mesa - under the MIT licensed
+  * Display list ID allocator ported from [util_idalloc](https://gitlab.freedesktop.org/mesa/mesa/-/blob/main/src/util/u_idalloc.c) (Copyright 2017 Valve Corporation)
+  * FFP vertex shader generation inspired by ffvertex_prog.c (Copyright 2007 VMware, Inc.)
+  * FFP fragment shader generation inspired by ff_fragment_shader.c (Copyright 2007, 2009 VMware, Inc. / 2010-2011 Intel Corporation)
+  * Fog parameter optimization inspired by st_nir_lower_fog.c (Copyright 2023 Google LLC) and prog_statevars.c (Copyright 1999-2007 Brian Paul)

build.gradle.kts

@@ -1,9 +1,23 @@
+import xyz.wagyourtail.jvmdg.gradle.flags.DowngradeFlags
+import xyz.wagyourtail.jvmdg.gradle.task.DowngradeJar
+import xyz.wagyourtail.jvmdg.gradle.task.files.DowngradeFiles
+
 plugins {
     id("com.gtnewhorizons.gtnhconvention")
 }
 
+tasks.withType<DowngradeJar>().configureEach { logLevel.set("FATAL") }
+tasks.withType<DowngradeFiles>().configureEach { logLevel.set("FATAL") }
+
 minecraft {
     extraRunJvmArguments.add("-Dangelica.enableTestBlocks=true")
+    extraRunJvmArguments.add("-Dangelica.dumpClass=true")
+//     extraRunJvmArguments.add("-Dangelica.useVulkan=true")
+//     extraRunJvmArguments.add("-Dangelica.vulkanDebug=true")
+//    extraRunJvmArguments.add("-Dorg.lwjgl.util.Debug=true")
+//    extraRunJvmArguments.addAll("-Dlegacy.debugClassLoadingSave=true")
+//    extraRunJvmArguments.addAll("-Drfb.dumpLoadedClasses=true", "-Drfb.dumpLoadedClassesPerTransformer=true")
+    //extraRunJvmArguments.add("-Dangelica.redirectorLogspam=true")
 }
 
 tasks.test {
@@ -11,17 +25,23 @@ tasks.test {
     testLogging {
         events("passed", "skipped", "failed")
     }
+    // On macOS ARM64, use an ARM64-compatible JVM for tests
+    val isMacOsArm64 = System.getProperty("os.name").lowercase().contains("mac") && System.getProperty("os.arch") == "aarch64"
     javaLauncher = javaToolchains.launcherFor {
         languageVersion = JavaLanguageVersion.of(8)
+        if (isMacOsArm64) {
+            vendor = JvmVendorSpec.AZUL
+        }
     }
     dependsOn(tasks.extractNatives2)
     jvmArgs("-Djava.library.path=${tasks.extractNatives2.get().destinationFolder.asFile.get().path}")
 }
 
 tasks.processResources {
-    inputs.property("version", project.version.toString())
+    val projectVersion = project.version.toString()
+    inputs.property("version", projectVersion)
     filesMatching("META-INF/rfb-plugin/*") {
-        expand("version" to project.version.toString())
+        expand("version" to projectVersion)
     }
 }
 
@@ -31,3 +51,51 @@ tasks.register<Copy>("copyDependencies") {
     from(configurations.default)
     into("testDependencies")
 }
+
+val embedOnly: Configuration by configurations
+val shadowImplementation: Configuration by configurations
+
+val downgradeEmbedOnlyForTest by tasks.registering(DowngradeFiles::class) {
+    inputCollection = embedOnly
+}
+
+val stripModuleInfoFromShadow by tasks.registering(Jar::class) {
+    dependsOn(shadowImplementation)
+    from(shadowImplementation.map(::zipTree))
+    exclude("module-info.class")
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+    archiveClassifier = "shadow-stripped"
+}
+
+val downgradeShadowImplForTest by tasks.registering(DowngradeFiles::class) {
+    inputCollection = files(stripModuleInfoFromShadow.map { it.archiveFile })
+    outputs.dir(temporaryDir)
+}
+
+tasks.test {
+    dependsOn(downgradeEmbedOnlyForTest, downgradeShadowImplForTest)
+    classpath = classpath
+        .minus(embedOnly)
+        .plus(files(downgradeEmbedOnlyForTest.map { it.outputCollection }))
+        .minus(shadowImplementation)
+        .plus(files({ fileTree(downgradeShadowImplForTest.get().temporaryDir) }))
+}
+
+tasks.shadowJar {
+    dependsOn(embedOnly)
+    from(embedOnly.map(::zipTree))
+
+    duplicatesStrategy = DuplicatesStrategy.INCLUDE
+    mergeServiceFiles()
+
+    minimize {
+        exclude(project(":glsm"))
+        exclude(project(":lwjgl3-backend"))
+    }
+
+    relocate("com.mitchej123", "com.mitchej123")
+    relocate("org.embeddedt", "org.embeddedt")
+    relocate("com.gtnewhorizons.angelica.glsm", "com.gtnewhorizons.angelica.glsm")
+    relocate("com.gtnewhorizons.angelica.lwjgl3", "com.gtnewhorizons.angelica.lwjgl3")
+}
+

dependencies.gradle

@@ -46,45 +46,88 @@ configurations {
     // Can be enabled for testing if desired
     // runtimeClasspath.extendsFrom(transformedMod)
     // testRuntimeClasspath.extendsFrom(transformedMod)
+
+    testRuntimeClasspath.exclude group: "com.github.GTNewHorizons", module: "lwjgl3ify"
+
+    // Embed in JAR without relocation (compile only, shadowed into JAR)
+    embedOnly
+    embedOnly.canBeConsumed = false
+    embedOnly.canBeResolved = true
+    compileClasspath.extendsFrom(embedOnly)
+    testCompileClasspath.extendsFrom(embedOnly)
+    testRuntimeClasspath.extendsFrom(embedOnly)
+
+}
+
+
+// Exclude self-reference from all configurations - prevents transitive Angelica deps from resolving against this project
+configurations.all {
+    exclude group: "com.github.GTNewHorizons", module: "Angelica"
 }
 
 dependencies {
-    compileOnly("com.github.GTNewHorizons:Hodgepodge:2.5.78")
+    compileOnly("com.github.GTNewHorizons:Hodgepodge:2.7.158:dev")
 
-    compileOnly("com.gtnewhorizons.retrofuturabootstrap:RetroFuturaBootstrap:0.4.0") { transitive = false }
+    compileOnly("com.gtnewhorizons.retrofuturabootstrap:RetroFuturaBootstrap:1.1.0") { transitive = false }
+//    runtimeOnlyNonPublishable("com.github.GTNewHorizons:lwjgl3ify:3.0.99")
 
-    compileOnly("org.projectlombok:lombok:1.18.22") { transitive = false }
-    annotationProcessor("org.projectlombok:lombok:1.18.22")
-
-    // Use modern models+textures to inject QuadProviders
-    devOnlyNonPublishable('com.github.GTNewHorizons:TX-Loader:1.7.2:dev')
+    compileOnly("org.projectlombok:lombok:1.18.42") { transitive = false }
+    annotationProcessor("org.projectlombok:lombok:1.18.42")
 
     // Iris Shaders
-    compileOnly('org.jetbrains:annotations:24.0.1')
-    api("com.github.GTNewHorizons:GTNHLib:0.5.20:dev")
+    compileOnly('org.jetbrains:annotations:26.0.2')
+    api("com.github.GTNewHorizons:GTNHLib:0.11.19:dev")
+
+    shadowImplementation(project(":glsm")) { transitive = false }
+    shadowImplementation(project(":lwjgl3-backend")) { transitive = false }
+    shadowImplementation("net.minecraftforge:eventbus:7.0-beta.15")
+
     shadowImplementation("org.anarres:jcpp:1.4.14") // Apache 2.0
-    shadowImplementation("org.taumc:glsl-transformation-lib:0.2.0-4.g6b42bca") {
+    shadowImplementation("org.taumc:glsl-transformation-lib:0.2.0-33.g3ec381e") {
         exclude module: "antlr4" // we only want to shadow the runtime module
     }
     shadowImplementation("org.antlr:antlr4-runtime:4.13.2")
     compileOnly "org.apache.ant:ant:1.8.2"
 
+    // Celeritas (transitive=false: deps provided by GTNHLib/runtime)
+    embedOnly("org.embeddedt.celeritas:celeritas-common:2.5.5-GTNH") { transitive = false }
+    embedOnly("org.embeddedt.celeritas:celeritas-lwjgl2-service:2.5.3-GTNH") { transitive = false }
+
     // Because who doesn't want NEI
-    devOnlyNonPublishable('com.github.GTNewHorizons:NotEnoughItems:2.6.45-GTNH:dev')
-    devOnlyNonPublishable('com.github.GTNewHorizons:CodeChickenCore:1.3.10:dev')
+    devOnlyNonPublishable('com.github.GTNewHorizons:NotEnoughItems:2.8.35-GTNH:dev')
+    devOnlyNonPublishable('com.github.GTNewHorizons:CodeChickenCore:1.4.7:dev')
+
+    // Display List Testing
+    /*
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:Applied-Energistics-2-Unofficial:rv3-beta-749-GTNH:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:ae2stuff:0.10.14-GTNH:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:BuildCraft:7.1.54:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:IguanaTweaksTConstruct:2.7.0:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:OpenBlocks:1.12.4-GTNH:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:OpenComputers:1.12.12-GTNH:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:TinkersConstruct:1.14.12-GTNH:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:ServerUtilities:2.2.13:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:ironchest:6.1.6:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:waila:1.9.7:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:Botania:1.13.15-GTNH:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:Mobs-Info:0.5.10-GTNH:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:Draconic-Evolution:1.5.18-GTNH:dev")
+    runtimeOnlyNonPublishable("com.github.GTNewHorizons:HoloInventory:2.5.8-GTNH:dev")
+     */
+
+    //devOnlyNonPublishable('com.github.GTNewHorizons:worldedit-gtnh:v0.0.9')
 
     // Notfine Deps
     compileOnly("thaumcraft:Thaumcraft:1.7.10-4.2.3.5:dev")
-    devOnlyNonPublishable("com.github.GTNewHorizons:Baubles:1.0.4:dev")
-    compileOnly("com.github.GTNewHorizons:twilightforest:2.6.35:dev") { transitive = false }
+    devOnlyNonPublishable("com.github.GTNewHorizons:Baubles-Expanded:2.2.2-GTNH:dev")
+    compileOnly("com.github.GTNewHorizons:twilightforest:2.7.13:dev") { transitive = false }
     compileOnly(rfg.deobf('curse.maven:witchery-69673:2234410'))
-    compileOnly("com.github.GTNewHorizons:TinkersConstruct:1.12.14-GTNH:dev") { transitive = false }
-    compileOnly("com.github.GTNewHorizons:Natura:2.7.5:dev")
+    compileOnly("com.github.GTNewHorizons:TinkersConstruct:1.14.6-GTNH:dev") { transitive = false }
+    compileOnly("com.github.GTNewHorizons:Natura:2.8.9:dev")
 
-    compileOnly("com.github.GTNewHorizons:ThaumicHorizons:1.6.4:dev")
+    compileOnly("com.github.GTNewHorizons:ThaumicHorizons:1.8.4:dev")
 
-    compileOnly("com.github.GTNewHorizons:Battlegear2:1.4.1:dev") { transitive = false }
-    compileOnly(rfg.deobf('maven.modrinth:backhand:1.4.1')) { transitive = false }
+    compileOnly("com.github.GTNewHorizons:Battlegear2:1.4.3:dev") { transitive = false }
 
     compileOnly("com.falsepattern:chunkapi-mc1.7.10:0.5.1:api") { transitive = false }
     compileOnly("com.falsepattern:endlessids-mc1.7.10:1.5-beta0003:dev") { transitive = false }
@@ -94,25 +137,49 @@ dependencies {
 
     compileOnly("curse.maven:minefactory-reloaded-66672:2277486")
 
-    compileOnly("com.github.GTNewHorizons:NotEnoughIds:2.1.6:dev") // Mixin Version
-    compileOnly("com.github.GTNewHorizons:NotEnoughIds-Legacy:1.4.7:dev") // ASM Version
+    compileOnly("com.github.GTNewHorizons:NotEnoughIds:2.1.10:dev")
+
+    compileOnly(rfg.deobf("maven.modrinth:ntmspace:X5663_H261"))
 
     compileOnly(rfg.deobf("curse.maven:campfirebackport-387444:4611675"))
     compileOnly(rfg.deobf("curse.maven:xaeros-minimap-263420:5060684"))
+    compileOnly(rfg.deobf("curse.maven:security-craft-64760:2818228"))
+    compileOnly("ganymedes01.etfuturum:Et-Futurum-Requiem:2.6.49-GTNH:dev")
+    compileOnly(rfg.deobf("curse.maven:biomes-o-plenty-220318:2499612"))
 
-    compileOnly("com.github.GTNewHorizons:HoloInventory:2.4.13-GTNH:dev")
+    devOnlyNonPublishable("com.github.GTNewHorizons:CosmeticArmorReworked:1.0.3-GTNH:dev")
 
-    runtimeOnlyNonPublishable(rfg.deobf("CoreTweaks:CoreTweaks:0.3.3.2"))
+    // For testing alternative splash screens — https://github.com/MalTeeez/ModernSplash/releases
+    // devOnlyNonPublishable("com.github.MalTeeez:modernsplash:1.7.10-1.2.4:dev")
 
     // Hodgepodge
     transformedMod("net.industrial-craft:industrialcraft-2:2.2.828-experimental:dev")
 
     // Better Crashes
-    compileOnly("com.github.GTNewHorizons:BetterCrashes:1.4.0-GTNH:dev")
+    compileOnly("com.github.GTNewHorizons:BetterCrashes:1.4.1-GTNH:dev")
 
-    // Tests
-    testImplementation(platform('org.junit:junit-bom:5.9.2'))
-    testImplementation('org.junit.jupiter:junit-jupiter')
-    testImplementation("org.mockito:mockito-core:3.+")
-    testImplementation("org.lwjgl.lwjgl:lwjgl:2.9.4-nightly-20150209")
+    // Distant Horizons
+    compileOnly("maven.modrinth:DistantHorizonsApi:5.1.0")
+
+    afterEvaluate {
+        dependencies {
+            testImplementation(platform('org.junit:junit-bom:5.14.1'))
+            testImplementation('org.junit.jupiter:junit-jupiter')
+            testImplementation("org.mockito:mockito-core:3.+")
+            testImplementation("org.lwjgl.lwjgl:lwjgl:2.9.4-nightly-20150209")
+
+            testImplementation('org.junit.platform:junit-platform-engine')
+            testImplementation('org.junit.platform:junit-platform-reporting')
+            testImplementation('org.junit.platform:junit-platform-launcher')
+
+            testImplementation('com.tngtech.archunit:archunit-junit5:1.4.1')
+
+            testRuntimeOnly("it.unimi.dsi:fastutil:8.5.18")
+            testRuntimeOnly("org.joml:joml:1.10.8")
+        }
+    }
+
+    compileOnly("mega:fluidlogged-mc1.7.10:0.1.2")
+
+    compileOnly("com.cardinalstar.cubicchunks:CubicChunks1710:v0.1.5-alpha:dev") { transitive = false }
 }

glsm/build.gradle.kts

@@ -0,0 +1,215 @@
+import xyz.wagyourtail.jvmdg.gradle.task.files.DowngradeFiles
+
+plugins {
+    `java-library`
+    `maven-publish`
+}
+
+apply(plugin = "xyz.wagyourtail.jvmdowngrader")
+
+version = rootProject.version
+
+java {
+    toolchain.languageVersion.set(JavaLanguageVersion.of(21))
+    withSourcesJar()
+}
+
+// RFG variant attributes: the root Angelica project uses RetroFuturaGradle which expects
+// these attributes on dependencies. Without them, Gradle can't resolve the subproject variant.
+val rfgObfAttr = Attribute.of("com.gtnewhorizons.retrofuturagradle.obfuscation", String::class.java)
+val rfgTransformedAttr = Attribute.of("rfgDeobfuscatorTransformed", Boolean::class.javaObjectType)
+
+configurations {
+    listOf("apiElements", "runtimeElements").forEach { name ->
+        named(name) {
+            attributes {
+                attribute(rfgObfAttr, "mcp")
+                attribute(rfgTransformedAttr, true)
+            }
+        }
+    }
+}
+
+// Compile stubs: MC class signatures needed to resolve GTNHLib's type hierarchy.
+// Not included in the published jar — real MC classes are on the classpath at runtime.
+sourceSets {
+    create("stubs") {
+        java.srcDir("src/stubs/java")
+    }
+}
+
+// Exclude stubs from all output jars
+tasks.withType<Jar>().configureEach {
+    exclude("net/minecraft/**")
+}
+
+repositories {
+    maven {
+        name = "Mojang"
+        url = uri("https://libraries.minecraft.net")
+    }
+    maven {
+        name = "GTNH Maven"
+        url = uri("https://nexus.gtnewhorizons.com/repository/public/")
+    }
+    maven {
+        name = "Forge"
+        url = uri("https://maven.minecraftforge.net/")
+    }
+    maven {
+        name = "taumc"
+        url = uri("https://maven.taumc.org/releases")
+    }
+    maven {
+        name = "WagYourTail"
+        url = uri("https://maven.wagyourtail.xyz/releases")
+        content { includeGroup("xyz.wagyourtail.jvmdowngrader") }
+    }
+    mavenCentral()
+    mavenLocal()
+}
+
+dependencies {
+    // MC compile stubs
+    compileOnly(sourceSets["stubs"].output)
+
+    // LWJGL
+    compileOnly("org.lwjgl.lwjgl:lwjgl:${property("lwjglVersion")}")
+    compileOnly("org.lwjgl.lwjgl:lwjgl_util:${property("lwjglVersion")}")
+
+    compileOnly("org.ow2.asm:asm-tree:5.0.3")
+
+    // Our Deps
+    api("com.github.GTNewHorizons:GTNHLib:${property("gtnhlibVersion")}:dev")
+    api("net.minecraftforge:eventbus:${property("eventbusVersion")}")
+
+    compileOnly("org.embeddedt.celeritas:celeritas-common:${property("celeritasVersion")}") { isTransitive = false }
+    implementation("org.taumc:glsl-transformation-lib:${property("glslTransformLibVersion")}") { exclude(module = "antlr4") }
+    implementation("org.antlr:antlr4-runtime:${property("antlr4RuntimeVersion")}")
+    implementation("org.anarres:jcpp:${property("jcppVersion")}")
+
+    compileOnly("org.projectlombok:lombok:${property("lombokVersion")}") { isTransitive = false }
+    annotationProcessor("org.projectlombok:lombok:${property("lombokVersion")}")
+    compileOnly("org.jetbrains:annotations:${property("jetbrainsAnnotationsVersion")}")
+    compileOnly("org.apache.logging.log4j:log4j-api:${property("log4jVersion")}")
+
+    // Deps (normally from MC) - compile only, but needed at test runtime
+    compileOnly("com.google.guava:guava:${property("guavaVersion")}")
+    testRuntimeOnly("com.google.guava:guava:${property("guavaVersion")}")
+    testRuntimeOnly("it.unimi.dsi:fastutil:${property("fastutilVersion")}")
+    testRuntimeOnly("org.joml:joml:${property("jomlVersion")}") { isTransitive = false }
+
+    // Test
+    testImplementation(sourceSets["stubs"].output)
+    testImplementation(platform("org.junit:junit-bom:${property("junitBomVersion")}"))
+    testImplementation("org.junit.jupiter:junit-jupiter")
+    testImplementation("org.ow2.asm:asm-tree:9.7")
+    testImplementation("org.lwjgl.lwjgl:lwjgl:${property("lwjglVersion")}")
+    testRuntimeOnly("org.junit.platform:junit-platform-launcher")
+    testRuntimeOnly("org.apache.logging.log4j:log4j-core:${property("log4jVersion")}")
+    testRuntimeOnly("org.embeddedt.celeritas:celeritas-lwjgl2-service:${property("celeritasVersion")}") { isTransitive = false }
+    testRuntimeOnly("xyz.wagyourtail.jvmdowngrader:jvmdowngrader-java-api:${property("jvmDowngraderVersion")}:downgraded-8")
+    testRuntimeOnly("org.apache.commons:commons-lang3:${property("commonsLang3Version")}")
+}
+
+val depsToDowngrade by configurations.creating {
+    isCanBeConsumed = false
+    isCanBeResolved = true
+}
+
+dependencies {
+    depsToDowngrade("net.minecraftforge:eventbus:${property("eventbusVersion")}")
+    depsToDowngrade("org.embeddedt.celeritas:celeritas-common:${property("celeritasVersion")}") { isTransitive = false }
+}
+
+tasks.withType<DowngradeFiles>().configureEach {
+    downgradeTo.set(JavaVersion.VERSION_1_8)
+    multiReleaseOriginal.set(false)
+    multiReleaseVersions.set(emptySet())
+    logLevel.set("FATAL")
+}
+
+val downgradeDepsForTest by tasks.registering(DowngradeFiles::class) {
+    inputCollection = depsToDowngrade
+}
+
+val downgradeMainClasses by tasks.registering(DowngradeFiles::class) {
+    inputCollection = sourceSets["main"].output.classesDirs.plus(sourceSets["stubs"].output.classesDirs)
+    classpath = sourceSets["main"].compileClasspath
+    dependsOn(tasks.named("classes"), tasks.named("stubsClasses"))
+}
+
+val downgradeTestClasses by tasks.registering(DowngradeFiles::class) {
+    inputCollection = sourceSets["test"].output.classesDirs
+    classpath = sourceSets["test"].compileClasspath
+    sourceSets["test"].output.classesDirs.files.forEach { outputs.dir(temporaryDir.resolve(it.name)) }
+    dependsOn(tasks.named("testClasses"))
+}
+
+tasks.test {
+    useJUnitPlatform()
+
+    javaLauncher = javaToolchains.launcherFor {
+        languageVersion = JavaLanguageVersion.of(8)
+        if (System.getProperty("os.name").lowercase().contains("mac")
+            && System.getProperty("os.arch") == "aarch64") {
+            vendor = JvmVendorSpec.AZUL
+        }
+    }
+
+    dependsOn(downgradeMainClasses, downgradeTestClasses, downgradeDepsForTest)
+
+    val mainClassesDirs = sourceSets["main"].output.classesDirs
+        .plus(sourceSets["stubs"].output.classesDirs)
+    val testClassesDirs = sourceSets["test"].output.classesDirs
+
+    val downgradedTest = files(downgradeTestClasses.map { it.outputCollection })
+    val downgradedMain = files(downgradeMainClasses.map { it.outputCollection })
+    val downgradedDeps = files(downgradeDepsForTest.map { it.outputCollection })
+
+    setTestClassesDirs(downgradedTest)
+    classpath = downgradedTest
+        .plus(downgradedMain)
+        .plus(downgradedDeps)
+        .plus(classpath.minus(mainClassesDirs).minus(testClassesDirs).minus(depsToDowngrade))
+
+    val extractNatives = rootProject.tasks.named("extractNatives2")
+    dependsOn(extractNatives)
+    jvmArgs("-Djava.library.path=${extractNatives.get().property("destinationFolder").let { (it as DirectoryProperty).asFile.get().path }}")
+}
+
+val verifyTestsRan by tasks.registering {
+    val resultsDir = layout.buildDirectory.dir("test-results/test")
+    dependsOn(tasks.test)
+    doLast {
+        val dir = resultsDir.get().asFile
+        val xmls = dir.listFiles { f -> f.name.startsWith("TEST-") && f.name.endsWith(".xml") } ?: emptyArray()
+        check(xmls.isNotEmpty()) {
+            ":glsm:test produced no TEST-*.xml in $dir - test task likely went NO-SOURCE"
+        }
+    }
+}
+tasks.check { dependsOn(verifyTestsRan) }
+
+publishing {
+    publications {
+        create<MavenPublication>("mavenJava") {
+            groupId = "com.gtnewhorizons.angelica"
+            artifactId = "glsm"
+            version = rootProject.version.toString()
+            from(components["java"])
+        }
+    }
+    repositories {
+        if (System.getenv("MAVEN_USER") != null) {
+            maven {
+                name = "GTNHMaven"
+                url = uri(rootProject.findProperty("mavenPublishUrl")?.toString() ?: "https://nexus.gtnewhorizons.com/repository/releases/")
+                credentials {
+                    username = System.getenv("MAVEN_USER")
+                    password = System.getenv("MAVEN_PASSWORD")
+                }
+            }
+        }
+    }
+}

glsm/gradle.properties

@@ -0,0 +1,16 @@
+lwjglVersion = 2.9.4-nightly-20150209
+eventbusVersion = 7.0-beta.15
+celeritasVersion = 2.5.3-GTNH
+lombokVersion = 1.18.42
+log4jVersion = 2.0-beta9
+guavaVersion = 18.0
+gtnhlibVersion = 0.11.19
+fastutilVersion = 8.5.18
+jomlVersion = 1.10.8
+glslTransformLibVersion = 0.2.0-26.g5ee7d96-GTNH
+antlr4RuntimeVersion = 4.13.2
+jcppVersion = 1.4.14
+jetbrainsAnnotationsVersion = 26.0.2
+junitBomVersion = 5.14.1
+jvmDowngraderVersion = 1.3.5
+commonsLang3Version = 3.17.0

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/CompatShaderTransformer.java

@@ -0,0 +1,602 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement.Usage;
+import org.antlr.v4.runtime.tree.ParseTree;
+import org.antlr.v4.runtime.tree.TerminalNode;
+import org.taumc.glsl.grammar.GLSLLexer;
+import org.taumc.glsl.grammar.GLSLParser;
+import org.taumc.glsl.ShaderParser;
+import org.taumc.glsl.Transformer;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * Compat transformation for mod shaders running under core profile.
+ *
+ * <p>Handles:
+ * <ul>
+ *   <li>Matrix builtin replacement (gl_ModelViewMatrix, gl_ProjectionMatrix, etc.)</li>
+ *   <li>Vertex attribute replacement (gl_Vertex, gl_Color, gl_MultiTexCoord0/1, gl_Normal)</li>
+ *   <li>gl_TexCoord[N] varying array → per-index in/out declarations</li>
+ *   <li>Texture function renames (texture2D → texture, etc.)</li>
+ *   <li>Fragment output handling (gl_FragColor → layout-qualified out declarations)</li>
+ *   <li>Fog builtins (gl_Fog, gl_FogFragCoord)</li>
+ *   <li>gl_FrontColor → local variable in vertex shaders</li>
+ *   <li>shadow2D/shadow2DLod → texture/textureLod with vec4 wrapping</li>
+ *   <li>Version upgrade to 330 core minimum</li>
+ *   <li>Reserved word pre-parse renaming (texture-as-variable, sample, etc.)</li>
+ * </ul>
+ */
+public class CompatShaderTransformer {
+
+    private static final Pattern VERSION_PATTERN = Pattern.compile("#version[ \\t]+(\\d+)(?:[ \\t]+(\\w+))?");
+
+    private static final Pattern DEFINE_PATTERN = Pattern.compile("^\\s*#\\s*define\\s+.+$", Pattern.MULTILINE);
+
+    /** Compat builtins that trigger AST transformation. */
+    private static final Set<String> COMPAT_BUILTINS = Set.of(
+        "gl_ModelView", "gl_Projection", "gl_NormalMatrix", "gl_TextureMatrix",
+        "gl_FragColor", "gl_Fog", "gl_FrontColor", "gl_Color",
+        "gl_Vertex", "gl_MultiTexCoord", "gl_TexCoord", "gl_Normal", "ftransform",
+        "texture2D", "texture3D", "texelFetch2D", "texelFetch3D", "textureSize2D",
+        "shadow2D", "gl_FrontLightModelProduct",
+        "gl_LightSource", "gl_FrontMaterial"
+    );
+
+    private static final Pattern NEEDS_TRANSFORM_PATTERN = Pattern.compile(
+        String.join("|", COMPAT_BUILTINS) + "|\\b(?:attribute|varying)\\b"
+    );
+
+    private static final Map<String, String> MATRIX_RENAMES = Map.of(
+        "gl_ModelViewMatrix", "angelica_ModelViewMatrix",
+        "gl_ModelViewMatrixInverse", "angelica_ModelViewMatrixInverse",
+        "gl_ProjectionMatrix", "angelica_ProjectionMatrix",
+        "gl_ProjectionMatrixInverse", "angelica_ProjectionMatrixInverse",
+        "gl_NormalMatrix", "angelica_NormalMatrix"
+    );
+
+    private static final Path DUMP_DIR;
+    private static final AtomicInteger dumpCounter = new AtomicInteger(0);
+
+    static {
+        DUMP_DIR = Boolean.parseBoolean(System.getProperty("angelica.dumpShaders", "false")) ? Paths.get("compat_shaders") : null;
+    }
+
+    private static final int CACHE_SIZE = 32;
+    private record CacheKey(String source, boolean isFragment) {}
+    private static final Map<CacheKey, String> cache = Collections.synchronizedMap(
+        new LinkedHashMap<>(32, 0.75f, true) {
+            @Override protected boolean removeEldestEntry(Map.Entry<CacheKey, String> eldest) {
+            return size() > CACHE_SIZE;
+        }
+    });
+
+    public static void clearCache() {
+        cache.clear();
+    }
+
+    /**
+     * Transform a mod shader source for core profile compatibility.
+     */
+    public static String transform(String source, boolean isFragment) {
+        final boolean needsTransform = needsTransformation(source);
+        String result;
+        if (!needsTransform) {
+            result = fixupVersion(source);
+        } else {
+            final CacheKey key = new CacheKey(source, isFragment);
+            final String cached = cache.get(key);
+            if (cached != null) {
+                dumpShader(source, cached, isFragment, needsTransform);
+                return cached;
+            }
+
+            try {
+                result = transformInternal(source, isFragment);
+                cache.put(key, result);
+            } catch (Exception e) {
+                GLStateManager.LOGGER.warn("CompatShaderTransformer: AST transformation failed, falling back to version fixup only", e);
+                result = fixupVersion(source);
+            }
+        }
+
+        dumpShader(source, result, isFragment, needsTransform);
+        return result;
+    }
+
+    public static boolean isCoreShader(String source) {
+        final Matcher vm = VERSION_PATTERN.matcher(source);
+        if (vm.find()) {
+            final int version = Integer.parseInt(vm.group(1));
+            return version >= 330 && "core".equals(vm.group(2));
+        }
+        return false;
+    }
+
+    private static boolean needsTransformation(String source) {
+        if (isCoreShader(source)) return false;
+
+        return NEEDS_TRANSFORM_PATTERN.matcher(source).find();
+    }
+
+    private static String transformInternal(String source, boolean isFragment) {
+        final Matcher versionMatcher = VERSION_PATTERN.matcher(source);
+        int declaredVersion = 110;
+        if (versionMatcher.find()) {
+            declaredVersion = Integer.parseInt(versionMatcher.group(1));
+        }
+
+        final int targetVersion = Math.max(declaredVersion, RENDER_BACKEND != null ? RENDER_BACKEND.getMinGLSLVersion() : 330);
+
+        // Pre-parse reserved word renaming — prevents ANTLR parse failures
+        source = GlslTransformUtils.replaceTexture(source);
+        source = GlslTransformUtils.renameReservedWords(source, targetVersion);
+
+        final ShaderParser.ParsedShader parsedShader = ShaderParser.parseShader(source);
+        final Transformer transformer = new Transformer(parsedShader.full());
+
+        injectMatrixUniforms(transformer);
+
+        transformFog(transformer, isFragment, source);
+
+        // gl_FrontLightModelProduct.sceneColor → angelica_SceneColor uniform
+        if (source.contains("gl_FrontLightModelProduct")) {
+            transformer.injectVariable("uniform vec4 angelica_SceneColor;");
+            transformer.replaceExpression("gl_FrontLightModelProduct.sceneColor", "angelica_SceneColor");
+        }
+
+        // gl_LightSource[i] → struct + uniform array (both via injectFunction to keep struct before uniform)
+        if (source.contains("gl_LightSource")) {
+            transformer.injectFunction("struct angelica_LightSourceParameters {"
+                    + "vec4 ambient;vec4 diffuse;vec4 specular;vec4 position;vec4 halfVector;"
+                    + "vec3 spotDirection;float spotExponent;float spotCutoff;float spotCosCutoff;"
+                    + "float constantAttenuation;float linearAttenuation;float quadraticAttenuation;"
+                    + "};");
+            transformer.injectFunction("uniform angelica_LightSourceParameters angelica_LightSource[2];");
+            transformer.rename("gl_LightSource", "angelica_LightSource");
+        }
+
+        // gl_FrontMaterial → struct + uniform (both via injectFunction to keep struct before uniform)
+        if (source.contains("gl_FrontMaterial")) {
+            transformer.injectFunction("struct angelica_MaterialParameters {"
+                    + "vec4 emission;vec4 ambient;vec4 diffuse;vec4 specular;float shininess;"
+                    + "};");
+            transformer.injectFunction("uniform angelica_MaterialParameters angelica_FrontMaterial;");
+            transformer.rename("gl_FrontMaterial", "angelica_FrontMaterial");
+        }
+
+        // gl_FrontColor (vertex) → gl_Color (fragment) varying chain
+        // Vertex side is unconditional: fragment may read gl_Color without vertex writing gl_FrontColor.
+        // Uses angelica_ prefix to avoid colliding with user-declared varyings (e.g. "v_Color").
+        if (!isFragment) {
+            transformer.injectVariable("out vec4 angelica_FrontColor;");
+            transformer.rename("gl_FrontColor", "angelica_FrontColor");
+            transformer.prependMain("angelica_FrontColor = vec4(1.0);");
+
+            final FFPInputs ffp = FFPInputs.detect(source);
+            assignVertexInputLocations(transformer, ffp);
+            transformVertexAttributes(transformer, source, ffp);
+        } else {
+            if (source.contains("gl_Color")) {
+                transformer.injectVariable("in vec4 angelica_FrontColor;");
+                transformer.rename("gl_Color", "angelica_FrontColor");
+            }
+        }
+
+        // gl_TexCoord[N] varying array → per-index in/out declarations
+        final Set<Integer> texCoordIndices = new HashSet<>();
+        transformer.renameArray("gl_TexCoord", "angelica_TexCoord", texCoordIndices);
+        for (Integer i : texCoordIndices) {
+            final String qualifier = isFragment ? "in" : "out";
+            transformer.injectVariable(qualifier + " vec4 angelica_TexCoord" + i + ";");
+        }
+
+        // Fragment output handling + alpha test discard
+        if (isFragment) {
+            transformFragmentOutputs(transformer);
+        }
+
+        // texture-as-variable collision handling
+        if (transformer.containsCall("texture") && transformer.hasVariable("texture")) {
+            transformer.rename("texture", "gtexture");
+        }
+        if (transformer.hasVariable("angelica_renamed_texture")) {
+            transformer.rename("angelica_renamed_texture", "gtexture");
+        }
+
+        transformer.renameFunctionCall(GlslTransformUtils.TEXTURE_RENAMES);
+
+        transformer.renameAndWrapShadow("shadow2D", "texture");
+        transformer.renameAndWrapShadow("shadow2DLod", "textureLod");
+
+        final String versionDirective = "#version " + targetVersion + " core\n";
+        final String extensions = VERSION_PATTERN.matcher(GlslTransformUtils.getFormattedShader(parsedShader.pre(), "")).replaceFirst("").trim();
+
+        // Preserve #define directives
+        final StringBuilder defines = new StringBuilder();
+        final Matcher defineMatcher = DEFINE_PATTERN.matcher(source);
+        while (defineMatcher.find()) {
+            defines.append(defineMatcher.group().trim()).append('\n');
+        }
+
+        final String header = versionDirective + (extensions.isEmpty() ? "" : "\n" + extensions) + (defines.isEmpty() ? "" : "\n" + defines);
+        final StringBuilder result = new StringBuilder();
+        transformer.mutateTree(tree -> result.append(GlslTransformUtils.getFormattedShader(tree, header)));
+
+        // Restore pre-parse renames
+        String output = GlslTransformUtils.restoreReservedWords(result.toString());
+
+        // Core profile: attribute → in, varying → out (vertex) / in (fragment)
+        output = fixupQualifiers(output, isFragment);
+
+        return output;
+    }
+
+    /**
+     * Inject matrix uniforms and rename compat builtins.
+     */
+    private static void injectMatrixUniforms(Transformer transformer) {
+        transformer.injectVariable("uniform mat4 angelica_ModelViewMatrix;");
+        transformer.injectVariable("uniform mat4 angelica_ModelViewMatrixInverse;");
+        transformer.injectVariable("uniform mat4 angelica_ProjectionMatrix;");
+        transformer.injectVariable("uniform mat4 angelica_ProjectionMatrixInverse;");
+        transformer.injectVariable("uniform mat3 angelica_NormalMatrix;");
+        transformer.injectVariable("uniform mat4 angelica_LightmapTextureMatrix;");
+
+        transformer.rename(MATRIX_RENAMES);
+
+        // Expression replacements
+        transformer.replaceExpression("gl_ModelViewProjectionMatrix", "(angelica_ProjectionMatrix * angelica_ModelViewMatrix)");
+        transformer.replaceExpression("gl_TextureMatrix[0]", "mat4(1.0)");
+        transformer.replaceExpression("gl_TextureMatrix[1]", "angelica_LightmapTextureMatrix");
+        transformer.replaceExpression(
+                "gl_TextureMatrix",
+                "mat4[8](mat4(1.0), angelica_LightmapTextureMatrix, mat4(1.0), mat4(1.0), mat4(1.0), mat4(1.0), mat4(1.0), mat4(1.0))");
+    }
+
+    /**
+     * Transform fragment outputs for core profile.
+     */
+    private static void transformFragmentOutputs(Transformer transformer) {
+        if (transformer.containsCall("gl_FragColor")) {
+            transformer.replaceExpression("gl_FragColor", "gl_FragData[0]");
+        }
+
+        final Set<Integer> found = new HashSet<>();
+        transformer.renameArray("gl_FragData", "angelica_FragData", found);
+
+        for (Integer i : found) {
+            transformer.injectVariable("layout (location = " + i + ") out vec4 angelica_FragData" + i + ";");
+        }
+
+        // Core profile: GL_ALPHA_TEST is removed - inject runtime discard using GLSM-tracked alpha reference (uploaded by CompatUniformManager).
+        if (found.contains(0)) {
+            transformer.injectVariable("uniform float angelica_currentAlphaTest;");
+            transformer.appendMain("if (angelica_FragData0.a <= angelica_currentAlphaTest) discard;");
+        }
+    }
+
+    private static void transformFog(Transformer transformer, boolean isFragment, String source) {
+        // Vertex side is unconditional: fragment may read gl_FogFragCoord without vertex writing it
+        transformer.rename("gl_FogFragCoord", "angelica_FogFragCoord");
+        if (!isFragment) {
+            transformer.injectVariable("out float angelica_FogFragCoord;");
+            transformer.prependMain("angelica_FogFragCoord = 0.0;");
+        } else {
+            if (source.contains("gl_FogFragCoord")) {
+                transformer.injectVariable("in float angelica_FogFragCoord;");
+            }
+        }
+
+        transformer.rename("gl_Fog", "angelica_Fog");
+        transformer.injectVariable("uniform float angelica_FogDensity;");
+        transformer.injectVariable("uniform float angelica_FogStart;");
+        transformer.injectVariable("uniform float angelica_FogEnd;");
+        transformer.injectVariable("uniform vec4 angelica_FogColor;");
+        transformer.injectFunction("struct angelica_FogParameters {vec4 color;float density;float start;float end;float scale;};");
+        transformer.injectFunction("angelica_FogParameters angelica_Fog = angelica_FogParameters("
+                + "angelica_FogColor, angelica_FogDensity, angelica_FogStart, angelica_FogEnd, "
+                + "1.0 / (angelica_FogEnd - angelica_FogStart));");
+    }
+
+    /**
+     * Replace removed FFP vertex attributes with explicit {@code in} declarations at core profile attribute locations.
+     */
+    private static void transformVertexAttributes(Transformer transformer, String source, FFPInputs ffp) {
+        if (ffp.position()) {
+            transformer.injectVariable("layout(location = 0) in vec4 angelica_Vertex;");
+            transformer.rename("gl_Vertex", "angelica_Vertex");
+        }
+        // gl_Color in vertex shaders is the per-vertex color attribute, distinct from the fragment gl_Color (interpolated gl_FrontColor) handled above
+        if (ffp.color()) {
+            transformer.injectVariable("layout(location = 1) in vec4 angelica_Color;");
+            transformer.rename("gl_Color", "angelica_Color");
+        }
+        if (ffp.uv0()) {
+            transformer.injectVariable("layout(location = 2) in vec4 angelica_MultiTexCoord0;");
+            transformer.rename("gl_MultiTexCoord0", "angelica_MultiTexCoord0");
+        }
+        if (ffp.uv1()) {
+            transformer.injectVariable("layout(location = 3) in vec4 angelica_MultiTexCoord1;");
+            transformer.rename("gl_MultiTexCoord1", "angelica_MultiTexCoord1");
+        }
+        if (ffp.normal()) {
+            transformer.injectVariable("layout(location = 4) in vec3 angelica_Normal;");
+            transformer.rename("gl_Normal", "angelica_Normal");
+        }
+        if (source.contains("ftransform")) {
+            transformer.replaceExpression("ftransform()", "(angelica_ProjectionMatrix * angelica_ModelViewMatrix * angelica_Vertex)");
+        }
+    }
+
+    private static final int MAX_VERTEX_ATTRIBS = 16;
+
+    private record FFPInputs(boolean position, boolean color, boolean uv0, boolean uv1, boolean normal) {
+        static FFPInputs detect(String source) {
+            return new FFPInputs(
+                source.contains("gl_Vertex") || source.contains("ftransform"),
+                source.contains("gl_Color"),
+                source.contains("gl_MultiTexCoord0"),
+                source.contains("gl_MultiTexCoord1"),
+                source.contains("gl_Normal"));
+        }
+    }
+
+    /** Adaptation of Mesa's assign_attribute_or_color_locations */
+    private static void assignVertexInputLocations(Transformer transformer, FFPInputs ffp) {
+        int used = 0;
+        if (ffp.position()) used |= 1 << Usage.POSITION.getAttributeLocation();
+        if (ffp.color()) used |= 1 << Usage.COLOR.getAttributeLocation();
+        if (ffp.uv0()) used |= 1 << Usage.PRIMARY_UV.getAttributeLocation();
+        if (ffp.uv1()) used |= 1 << Usage.SECONDARY_UV.getAttributeLocation();
+        if (ffp.normal()) used |= 1 << Usage.NORMAL.getAttributeLocation();
+
+        record Input(String name, String baseType, String arraySuffix, int slots, int index) {}
+        final List<Input> toAssign = new ArrayList<>();
+        int index = 0;
+
+        for (TerminalNode storage : transformer.collectStorage()) {
+            final int tokenType = storage.getSymbol().getType();
+            if (tokenType != GLSLLexer.ATTRIBUTE && tokenType != GLSLLexer.IN) continue;
+
+            ParseTree node = storage.getParent();
+            while (node != null && !(node instanceof GLSLParser.Single_declarationContext)) {
+                node = node.getParent();
+            }
+            if (!(node instanceof GLSLParser.Single_declarationContext decl)) continue;
+            if (decl.typeless_declaration() == null) continue;
+
+            final GLSLParser.Type_specifierContext typeSpec = decl.fully_specified_type().type_specifier();
+            final String baseType = GlslTransformUtils.getFormattedShader(typeSpec.type_specifier_nonarray(), "").trim();
+            final int typeArraySlots = arraySlots(typeSpec.array_specifier());
+            final String typeArray = arraySuffix(typeSpec.array_specifier());
+
+            if (hasLayoutQualifier(decl)) {
+                final int loc = explicitLocation(decl);
+                final int slots = baseSlots(baseType) * typeArraySlots * arraySlots(decl.typeless_declaration().array_specifier());
+                if (loc >= 0) used |= slotMask(slots) << loc;
+                continue;
+            }
+
+            final List<GLSLParser.Typeless_declarationContext> declarators = new ArrayList<>();
+            declarators.add(decl.typeless_declaration());
+            if (decl.getParent() instanceof GLSLParser.Init_declarator_listContext list) {
+                declarators.addAll(list.typeless_declaration());
+            }
+            for (GLSLParser.Typeless_declarationContext d : declarators) {
+                if (d.IDENTIFIER() == null) continue;
+                final int slots = baseSlots(baseType) * typeArraySlots * arraySlots(d.array_specifier());
+                final String arraySuffix = typeArray + arraySuffix(d.array_specifier());
+                toAssign.add(new Input(d.IDENTIFIER().getText(), baseType, arraySuffix, slots, index++));
+            }
+        }
+
+        toAssign.sort((a, b) -> a.slots() != b.slots() ? b.slots() - a.slots() : a.index() - b.index());
+
+        for (Input in : toAssign) {
+            final int loc = findAvailableSlots(used, in.slots());
+            if (loc < 0) continue;
+            used |= slotMask(in.slots()) << loc;
+            transformer.removeVariable(in.name());
+            transformer.variable = null;
+            transformer.injectVariable("layout(location = " + loc + ") in " + in.baseType() + " " + in.name() + in.arraySuffix() + ";");
+        }
+    }
+
+    private static String arraySuffix(GLSLParser.Array_specifierContext arraySpec) {
+        return arraySpec != null ? GlslTransformUtils.getFormattedShader(arraySpec, "").trim() : "";
+    }
+
+    private static int arraySlots(GLSLParser.Array_specifierContext arraySpec) {
+        if (arraySpec == null) return 1;
+        int product = 1;
+        for (GLSLParser.DimensionContext dim : arraySpec.dimension()) {
+            if (dim.constant_expression() == null) continue;
+            try {
+                product *= Integer.decode(GlslTransformUtils.getFormattedShader(dim.constant_expression(), "").trim());
+            } catch (NumberFormatException ignored) {}
+        }
+        return product;
+    }
+
+    private static int baseSlots(String type) {
+        final String dims = type.startsWith("dmat") ? type.substring(4) : type.startsWith("mat") ? type.substring(3) : null;
+        if (dims != null && !dims.isEmpty() && Character.isDigit(dims.charAt(0))) {
+            return dims.charAt(0) - '0';
+        }
+        return 1;
+    }
+
+    private static int slotMask(int slots) {
+        return (slots >= 32) ? -1 : (1 << slots) - 1;
+    }
+
+    private static int findAvailableSlots(int used, int needed) {
+        if (needed <= 0) return -1;
+        final int mask = slotMask(needed);
+        for (int i = 0; i <= MAX_VERTEX_ATTRIBS - needed; i++) {
+            if (((mask << i) & ~used) == (mask << i)) return i;
+        }
+        return -1;
+    }
+
+    private static int explicitLocation(GLSLParser.Single_declarationContext decl) {
+        final GLSLParser.Type_qualifierContext qualifier = decl.fully_specified_type().type_qualifier();
+        if (qualifier == null) return -1;
+        for (GLSLParser.Single_type_qualifierContext single : qualifier.single_type_qualifier()) {
+            final GLSLParser.Layout_qualifierContext layout = single.layout_qualifier();
+            if (layout == null) continue;
+            for (GLSLParser.Layout_qualifier_idContext id : layout.layout_qualifier_id_list().layout_qualifier_id()) {
+                if (id.IDENTIFIER() != null && "location".equals(id.IDENTIFIER().getText()) && id.constant_expression() != null) {
+                    try {
+                        return Integer.decode(GlslTransformUtils.getFormattedShader(id.constant_expression(), "").trim());
+                    } catch (NumberFormatException ignored) {
+                        return -1;
+                    }
+                }
+            }
+        }
+        return -1;
+    }
+
+    private static boolean hasLayoutQualifier(GLSLParser.Single_declarationContext decl) {
+        final GLSLParser.Type_qualifierContext qualifier = decl.fully_specified_type().type_qualifier();
+        if (qualifier == null) return false;
+        for (GLSLParser.Single_type_qualifierContext single : qualifier.single_type_qualifier()) {
+            if (single.layout_qualifier() != null) return true;
+        }
+        return false;
+    }
+
+    private static void dumpShader(String original, String transformed, boolean isFragment, boolean wasTransformed) {
+        if (DUMP_DIR == null) return;
+        final int id = dumpCounter.getAndIncrement();
+        final String suffix = isFragment ? ".frag.glsl" : ".vert.glsl";
+        try {
+            Files.createDirectories(DUMP_DIR);
+            // Capture caller info for identification
+            final String caller = identifyCaller();
+            final String header = "// Compat shader dump #" + id + " (" + (isFragment ? "fragment" : "vertex") + ")"
+                + "\n// Transformed: " + wasTransformed
+                + "\n// Caller: " + caller + "\n\n";
+            Files.writeString(DUMP_DIR.resolve(id + "_original" + suffix), header + original, StandardCharsets.UTF_8);
+            Files.writeString(DUMP_DIR.resolve(id + "_transformed" + suffix), header + transformed, StandardCharsets.UTF_8);
+        } catch (IOException e) {
+            GLStateManager.LOGGER.warn("Failed to dump compat shader: {}", e.getMessage());
+        }
+    }
+
+    private static String identifyCaller() {
+        for (StackTraceElement frame : Thread.currentThread().getStackTrace()) {
+            final String cls = frame.getClassName();
+            if (!cls.startsWith("com.gtnewhorizons.angelica.glsm.")
+                && !cls.startsWith("java.")
+                && !cls.equals("org.lwjgl.opengl.GL20")) {
+                return cls + "." + frame.getMethodName() + ":" + frame.getLineNumber();
+            }
+        }
+        return "unknown";
+    }
+
+    private static final Pattern ATTRIBUTE_PATTERN = Pattern.compile("\\battribute\\b");
+    private static final Pattern VARYING_PATTERN = Pattern.compile("\\bvarying\\b");
+
+    /** Replace legacy storage qualifiers removed in core profile. Safe on AST-serialized output (no comments). */
+    public static String fixupQualifiers(String source, boolean isFragment) {
+        source = ATTRIBUTE_PATTERN.matcher(source).replaceAll("in");
+        source = VARYING_PATTERN.matcher(source).replaceAll(isFragment ? "in" : "out");
+        return source;
+    }
+
+    // Patterns for parsing fragment shader in declarations to generate passthrough vertex shaders
+    private static final Pattern FRAG_IN_COLOR = Pattern.compile("\\bin\\s+vec4\\s+angelica_FrontColor\\b");
+    private static final Pattern FRAG_IN_TEXCOORD = Pattern.compile("\\bin\\s+vec4\\s+angelica_TexCoord(\\d+)\\b");
+    private static final Pattern FRAG_IN_FOGCOORD = Pattern.compile("\\bin\\s+float\\s+angelica_FogFragCoord\\b");
+
+    /**
+     * Generate a passthrough vertex shader for a fragment-only program.
+     *
+     * @param fragmentSource the transformed fragment shader source
+     * @return a complete vertex shader source string
+     */
+    public static String generatePassthroughVertexShader(String fragmentSource) {
+        final StringBuilder sb = new StringBuilder(512);
+        sb.append("#version 330 core\n\n");
+
+        // Always have position
+        sb.append("layout(location = 0) in vec4 a_Position;\n");
+
+        // Matrix uniforms for position transform
+        sb.append("uniform mat4 angelica_ModelViewMatrix;\n");
+        sb.append("uniform mat4 angelica_ProjectionMatrix;\n");
+
+        final StringBuilder varyings = new StringBuilder();
+        final StringBuilder assignments = new StringBuilder();
+        if (FRAG_IN_COLOR.matcher(fragmentSource).find()) {
+            sb.append("layout(location = 1) in vec4 a_Color;\n");
+            varyings.append("out vec4 angelica_FrontColor;\n");
+            assignments.append("  angelica_FrontColor = a_Color;\n");
+        }
+
+        final Matcher texCoordMatcher = FRAG_IN_TEXCOORD.matcher(fragmentSource);
+        final Set<Integer> texCoordIndices = new HashSet<>();
+        while (texCoordMatcher.find()) {
+            texCoordIndices.add(Integer.parseInt(texCoordMatcher.group(1)));
+        }
+        for (int i : texCoordIndices) {
+            // PRIMARY_UV=2, SECONDARY_UV=3. Only indices 0 and 1 are supported; higher indices collide at location 3.
+            final int location = i == 0 ? 2 : 3;
+            sb.append("layout(location = ").append(location).append(") in vec4 a_TexCoord").append(i).append(";\n");
+            varyings.append("out vec4 angelica_TexCoord").append(i).append(";\n");
+            assignments.append("  angelica_TexCoord").append(i).append(" = a_TexCoord").append(i).append(";\n");
+        }
+
+        if (FRAG_IN_FOGCOORD.matcher(fragmentSource).find()) {
+            varyings.append("out float angelica_FogFragCoord;\n");
+            assignments.append("  angelica_FogFragCoord = abs((angelica_ModelViewMatrix * a_Position).z);\n");
+        }
+
+        sb.append(varyings);
+        sb.append("\nvoid main() {\n");
+        sb.append("  gl_Position = angelica_ProjectionMatrix * angelica_ModelViewMatrix * a_Position;\n");
+        sb.append(assignments);
+        sb.append("}\n");
+
+        return sb.toString();
+    }
+
+    /** Ensure #version is at least 330 core, strip 'compatibility' profile. */
+    private static String fixupVersion(String source) {
+        final Matcher m = VERSION_PATTERN.matcher(source);
+        if (!m.find()) {
+            return "#version 330 core\n" + source;
+        }
+
+        final int version = Integer.parseInt(m.group(1));
+        final String profile = m.group(2);
+
+        if (version >= 330 && !"compatibility".equals(profile)) {
+            if ("core".equals(profile)) return source;
+            return m.replaceFirst("#version " + version + " core");
+        }
+
+        final int targetVersion = Math.max(version, 330);
+        return m.replaceFirst("#version " + targetVersion + " core");
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/CompatUniformManager.java

@@ -0,0 +1,448 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.stacks.FogStateStack;
+import com.gtnewhorizons.angelica.glsm.stacks.LightStateStack;
+import com.gtnewhorizons.angelica.glsm.states.ClipPlaneState;
+import com.gtnewhorizons.angelica.glsm.states.LightModelState;
+import com.gtnewhorizons.angelica.glsm.states.LightState;
+import com.gtnewhorizons.angelica.glsm.states.MaterialState;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import org.joml.Matrix3f;
+import org.joml.Matrix4f;
+import org.joml.Vector3f;
+import org.lwjgl.BufferUtils;
+import org.lwjgl.opengl.GL11;
+
+import java.nio.FloatBuffer;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * Per-program compat uniform location cache and upload manager.
+ *
+ * <p>Manages {@code angelica_*} uniforms injected by {@link CompatShaderTransformer} and {@code iris_*} matrix uniforms used by Iris/celeritas shader
+ * programs.
+ */
+public class CompatUniformManager {
+
+    // Uniform location indices within the cached array (package-private for tests)
+    static final int LOC_MODELVIEW = 0;
+    static final int LOC_MODELVIEW_INVERSE = 1;
+    static final int LOC_PROJECTION = 2;
+    static final int LOC_PROJECTION_INVERSE = 3;
+    static final int LOC_NORMAL = 4;
+    static final int LOC_LIGHTMAP_TEXTURE_MATRIX = 5;
+    static final int LOC_FOG_DENSITY = 6;
+    static final int LOC_FOG_START = 7;
+    static final int LOC_FOG_END = 8;
+    static final int LOC_FOG_COLOR = 9;
+    static final int LOC_IRIS_MODELVIEW = 10;
+    static final int LOC_IRIS_PROJECTION = 11;
+    static final int LOC_IRIS_NORMAL = 12;
+    static final int LOC_IRIS_LIGHTMAP_TEXTURE_MATRIX = 13;
+    static final int LOC_IRIS_TEXTURE_MATRIX = 14;
+    static final int LOC_ALPHA_TEST_REF = 15;
+    static final int LOC_SCENE_COLOR = 16;
+    static final int LOC_CLIP_PLANES = 17;
+    static final int LOC_CLIP_PLANES_ENABLED = 18;
+
+    // Light source fields: 12 per light × 2 lights = 24 locations
+    static final int LIGHT_FIELDS = 12;
+    static final int LF_AMBIENT = 0, LF_DIFFUSE = 1, LF_SPECULAR = 2, LF_POSITION = 3;
+    static final int LF_HALF_VECTOR = 4, LF_SPOT_DIRECTION = 5, LF_SPOT_EXPONENT = 6;
+    static final int LF_SPOT_CUTOFF = 7, LF_SPOT_COS_CUTOFF = 8;
+    static final int LF_CONSTANT_ATTEN = 9, LF_LINEAR_ATTEN = 10, LF_QUADRATIC_ATTEN = 11;
+    static final int LOC_LIGHT_BASE = 19;
+
+    // Material fields: 5 locations
+    static final int MF_EMISSION = 0, MF_AMBIENT = 1, MF_DIFFUSE = 2, MF_SPECULAR = 3, MF_SHININESS = 4;
+    static final int MAT_FIELDS = 5;
+    static final int LOC_MAT_BASE = LOC_LIGHT_BASE + 2 * LIGHT_FIELDS; // 43
+
+    static final int LOC_IRIS_MODELVIEW_INVERSE = LOC_MAT_BASE + MAT_FIELDS; // 48
+    static final int LOC_IRIS_PROJECTION_INVERSE = LOC_IRIS_MODELVIEW_INVERSE + 1; // 49
+
+    static final int LOC_COUNT = LOC_IRIS_PROJECTION_INVERSE + 1; // 50
+
+    private static final String[] LIGHT_FIELD_NAMES = {
+        "ambient", "diffuse", "specular", "position", "halfVector",
+        "spotDirection", "spotExponent", "spotCutoff", "spotCosCutoff",
+        "constantAttenuation", "linearAttenuation", "quadraticAttenuation",
+    };
+    private static final String[] MAT_FIELD_NAMES = {
+        "emission", "ambient", "diffuse", "specular", "shininess",
+    };
+
+    private static final String[] UNIFORM_NAMES;
+
+    static {
+        UNIFORM_NAMES = new String[LOC_COUNT];
+        UNIFORM_NAMES[LOC_MODELVIEW] = "angelica_ModelViewMatrix";
+        UNIFORM_NAMES[LOC_MODELVIEW_INVERSE] = "angelica_ModelViewMatrixInverse";
+        UNIFORM_NAMES[LOC_PROJECTION] = "angelica_ProjectionMatrix";
+        UNIFORM_NAMES[LOC_PROJECTION_INVERSE] = "angelica_ProjectionMatrixInverse";
+        UNIFORM_NAMES[LOC_NORMAL] = "angelica_NormalMatrix";
+        UNIFORM_NAMES[LOC_LIGHTMAP_TEXTURE_MATRIX] = "angelica_LightmapTextureMatrix";
+        UNIFORM_NAMES[LOC_FOG_DENSITY] = "angelica_FogDensity";
+        UNIFORM_NAMES[LOC_FOG_START] = "angelica_FogStart";
+        UNIFORM_NAMES[LOC_FOG_END] = "angelica_FogEnd";
+        UNIFORM_NAMES[LOC_FOG_COLOR] = "angelica_FogColor";
+        UNIFORM_NAMES[LOC_IRIS_MODELVIEW] = "iris_ModelViewMatrix";
+        UNIFORM_NAMES[LOC_IRIS_PROJECTION] = "iris_ProjectionMatrix";
+        UNIFORM_NAMES[LOC_IRIS_NORMAL] = "iris_NormalMatrix";
+        UNIFORM_NAMES[LOC_IRIS_LIGHTMAP_TEXTURE_MATRIX] = "iris_LightmapTextureMatrix";
+        UNIFORM_NAMES[LOC_IRIS_TEXTURE_MATRIX] = "iris_TextureMatrix";
+        UNIFORM_NAMES[LOC_IRIS_MODELVIEW_INVERSE] = "iris_ModelViewMatrixInverse";
+        UNIFORM_NAMES[LOC_IRIS_PROJECTION_INVERSE] = "iris_ProjectionMatrixInverse";
+        UNIFORM_NAMES[LOC_ALPHA_TEST_REF] = "angelica_currentAlphaTest";
+        UNIFORM_NAMES[LOC_SCENE_COLOR] = "angelica_SceneColor";
+        UNIFORM_NAMES[LOC_CLIP_PLANES] = "angelica_ClipPlane[0]";
+        UNIFORM_NAMES[LOC_CLIP_PLANES_ENABLED] = "angelica_ClipPlanesEnabled";
+        for (int li = 0; li < 2; li++) {
+            for (int fi = 0; fi < LIGHT_FIELDS; fi++) {
+                UNIFORM_NAMES[LOC_LIGHT_BASE + li * LIGHT_FIELDS + fi] = "angelica_LightSource[" + li + "]." + LIGHT_FIELD_NAMES[fi];
+            }
+        }
+        for (int fi = 0; fi < MAT_FIELDS; fi++) {
+            UNIFORM_NAMES[LOC_MAT_BASE + fi] = "angelica_FrontMaterial." + MAT_FIELD_NAMES[fi];
+        }
+    }
+
+    /** Per-program cached uniform locations + last-uploaded generations. Maps program ID -> state. */
+    private static final Int2ObjectOpenHashMap<ProgramUniforms> programUniforms = new Int2ObjectOpenHashMap<>();
+
+    private static final class ProgramUniforms {
+        final int[] locs;
+        int lastMvGen = -1, lastMvLinearGen = -1, lastProjGen = -1, lastTexMatGen = -1;
+        int lastFragmentGen = -1, lastLightingGen = -1, lastClipPlaneGen = -1;
+        ProgramUniforms(int[] locs) { this.locs = locs; }
+    }
+
+    // Reusable NIO buffers for upload
+    private static final FloatBuffer mat4Buf = BufferUtils.createFloatBuffer(16);
+    private static final FloatBuffer mat3Buf = BufferUtils.createFloatBuffer(9);
+    private static final FloatBuffer vec4Buf = BufferUtils.createFloatBuffer(4);
+    private static final FloatBuffer clipPlaneBuf = BufferUtils.createFloatBuffer(32); // 8 planes * vec4
+    private static final Matrix3f normalMatrix = new Matrix3f();
+    private static final Matrix4f scratchMatrix = new Matrix4f();
+    private static final Vector3f scratchCol = new Vector3f();
+
+    private static final float LIGHTMAP_SCALE = 1.0f / 256.0f;
+    private static final FloatBuffer lightmapMatrixBuf;
+
+    static {
+        lightmapMatrixBuf = BufferUtils.createFloatBuffer(16);
+        new Matrix4f().scale(LIGHTMAP_SCALE).translate(8.0f, 8.0f, 8.0f).get(lightmapMatrixBuf);
+    }
+
+    private CompatUniformManager() {}
+
+    /**
+     * Normalize each column of a 3x3 matrix in place. Used to strip the residual 1/scale that
+     * inverse-transpose introduces.
+     */
+    private static void normalizeColumnsInPlace(Matrix3f m) {
+        m.setColumn(0, m.getColumn(0, scratchCol).normalize());
+        m.setColumn(1, m.getColumn(1, scratchCol).normalize());
+        m.setColumn(2, m.getColumn(2, scratchCol).normalize());
+    }
+
+    public static void onLinkProgram(int program) {
+        int[] locs = new int[LOC_COUNT];
+        boolean hasAny = false;
+
+        for (int i = 0; i < LOC_COUNT; i++) {
+            locs[i] = RENDER_BACKEND.getUniformLocation(program, UNIFORM_NAMES[i]);
+            if (locs[i] != -1) hasAny = true;
+        }
+
+        if (hasAny) {
+            programUniforms.put(program, new ProgramUniforms(locs));
+            GLStateManager.LOGGER.debug("CompatUniformManager: program {} has compat uniforms", program);
+        }
+    }
+
+    /**
+     * Uploads the emulated uniforms.
+     *
+     * @return Whether the program needs emulation (FFP or Iris Program)
+     */
+    public static boolean refreshCompatUniforms(int program) {
+        final ProgramUniforms pu = programUniforms.get(program);
+        if (pu == null) return false;
+        final int[] locs = pu.locs;
+
+        // Matrix uniforms — skip if this program's storage already holds the current generation
+        final int mvGen = GLStateManager.mvGeneration;
+        final int mvLinearGen = GLStateManager.mvLinearGeneration;
+        final int projGen = GLStateManager.projGeneration;
+        final int texMatGen = GLStateManager.texMatrixGeneration;
+        final boolean mvChanged = mvGen != pu.lastMvGen;
+        final boolean mvLinearChanged = mvLinearGen != pu.lastMvLinearGen;
+        final boolean projChanged = projGen != pu.lastProjGen;
+        final boolean texMatChanged = texMatGen != pu.lastTexMatGen;
+        if (mvChanged || projChanged || texMatChanged) {
+            uploadMatrices(locs, mvChanged, mvLinearChanged, projChanged, texMatChanged);
+            pu.lastMvGen = mvGen;
+            pu.lastMvLinearGen = mvLinearGen;
+            pu.lastProjGen = projGen;
+            pu.lastTexMatGen = texMatGen;
+        }
+
+        // Fragment-category uniforms (fog, alpha) — skip if generation unchanged
+        final int fragGen = GLStateManager.fragmentGeneration;
+        if (fragGen != pu.lastFragmentGen) {
+            pu.lastFragmentGen = fragGen;
+            uploadFragmentUniforms(locs);
+        }
+
+        // Lighting-derived uniforms (scene color, light sources, material)
+        final int litGen = GLStateManager.lightingGeneration;
+        if (litGen != pu.lastLightingGen) {
+            pu.lastLightingGen = litGen;
+            if (locs[LOC_SCENE_COLOR] != -1) uploadSceneColor(locs);
+            uploadLightSources(locs);
+            uploadMaterial(locs);
+        }
+
+        // Clip plane equations + enabled bool — uploaded when enable state or equations change
+        if (locs[LOC_CLIP_PLANES] != -1 || locs[LOC_CLIP_PLANES_ENABLED] != -1) {
+            final int cpGen = GLStateManager.clipPlaneGeneration;
+            if (cpGen != pu.lastClipPlaneGen) {
+                pu.lastClipPlaneGen = cpGen;
+                uploadClipPlanes(locs);
+            }
+        }
+
+        return true;
+    }
+
+    private static void uploadMatrices(int[] locs, boolean mvChanged, boolean mvLinearChanged, boolean projChanged, boolean texMatChanged) {
+        final Matrix4f mv = GLStateManager.getModelViewMatrix();
+        final Matrix4f proj = GLStateManager.getProjectionMatrix();
+
+        if (mvChanged) {
+            // ModelView
+            if (locs[LOC_MODELVIEW] != -1 || locs[LOC_IRIS_MODELVIEW] != -1) {
+                mv.get(mat4Buf);
+                if (locs[LOC_MODELVIEW] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_MODELVIEW], false, mat4Buf);
+                }
+                if (locs[LOC_IRIS_MODELVIEW] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_MODELVIEW], false, mat4Buf);
+                }
+            }
+
+            // ModelView Inverse
+            if (locs[LOC_MODELVIEW_INVERSE] != -1 || locs[LOC_IRIS_MODELVIEW_INVERSE] != -1) {
+                mv.invert(scratchMatrix);
+                scratchMatrix.get(mat4Buf);
+                if (locs[LOC_MODELVIEW_INVERSE] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_MODELVIEW_INVERSE], false, mat4Buf);
+                }
+                if (locs[LOC_IRIS_MODELVIEW_INVERSE] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_MODELVIEW_INVERSE], false, mat4Buf);
+                }
+            }
+        }
+
+        if (mvLinearChanged) {
+            // Normal Matrix (inverse-transpose of upper-left 3x3 of ModelView)
+            if (locs[LOC_NORMAL] != -1 || locs[LOC_IRIS_NORMAL] != -1) {
+                mv.normal(normalMatrix);
+                if (locs[LOC_NORMAL] != -1) {
+                    normalMatrix.get(mat3Buf);
+                    RENDER_BACKEND.uniformMatrix3(locs[LOC_NORMAL], false, mat3Buf);
+                }
+                // Column-normalized to unit magnitude
+                if (locs[LOC_IRIS_NORMAL] != -1) {
+                    normalizeColumnsInPlace(normalMatrix);
+                    normalMatrix.get(mat3Buf);
+                    RENDER_BACKEND.uniformMatrix3(locs[LOC_IRIS_NORMAL], false, mat3Buf);
+                }
+            }
+        }
+
+        if (projChanged) {
+            // Projection
+            if (locs[LOC_PROJECTION] != -1 || locs[LOC_IRIS_PROJECTION] != -1) {
+                proj.get(mat4Buf);
+                if (locs[LOC_PROJECTION] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_PROJECTION], false, mat4Buf);
+                }
+                if (locs[LOC_IRIS_PROJECTION] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_PROJECTION], false, mat4Buf);
+                }
+            }
+
+            // Projection Inverse
+            if (locs[LOC_PROJECTION_INVERSE] != -1 || locs[LOC_IRIS_PROJECTION_INVERSE] != -1) {
+                proj.invert(scratchMatrix);
+                scratchMatrix.get(mat4Buf);
+                if (locs[LOC_PROJECTION_INVERSE] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_PROJECTION_INVERSE], false, mat4Buf);
+                }
+                if (locs[LOC_IRIS_PROJECTION_INVERSE] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_PROJECTION_INVERSE], false, mat4Buf);
+                }
+            }
+        }
+
+        if (texMatChanged) {
+            // Iris lightmap texture matrix (constant)
+            if (locs[LOC_IRIS_LIGHTMAP_TEXTURE_MATRIX] != -1) {
+                RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_LIGHTMAP_TEXTURE_MATRIX], false, lightmapMatrixBuf);
+            }
+
+            // angelica_LightmapTextureMatrix — actual GLSM texture unit 1 matrix (set by enableLightmap())
+            if (locs[LOC_LIGHTMAP_TEXTURE_MATRIX] != -1) {
+                GLStateManager.getTextures().getTextureUnitMatrix(1).get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(locs[LOC_LIGHTMAP_TEXTURE_MATRIX], false, mat4Buf);
+            }
+
+            // iris_TextureMatrix — texture unit 0 matrix (animated by glints, etc.)
+            if (locs[LOC_IRIS_TEXTURE_MATRIX] != -1) {
+                GLStateManager.getTextures().getTextureUnitMatrix(0).get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_TEXTURE_MATRIX], false, mat4Buf);
+            }
+        }
+    }
+
+    private static void uploadFragmentUniforms(int[] locs) {
+        // Fog uniforms
+        FogStateStack fog = GLStateManager.getFogState();
+        if (locs[LOC_FOG_DENSITY] != -1) {
+            RENDER_BACKEND.uniform1f(locs[LOC_FOG_DENSITY], Math.max(0.0f, fog.getDensity()));
+        }
+        if (locs[LOC_FOG_START] != -1) {
+            RENDER_BACKEND.uniform1f(locs[LOC_FOG_START], fog.getStart());
+        }
+        if (locs[LOC_FOG_END] != -1) {
+            RENDER_BACKEND.uniform1f(locs[LOC_FOG_END], fog.getEnd());
+        }
+        if (locs[LOC_FOG_COLOR] != -1) {
+            vec4Buf.clear();
+            vec4Buf.put((float) fog.getFogColor().x).put((float) fog.getFogColor().y).put((float) fog.getFogColor().z).put(fog.getFogAlpha());
+            vec4Buf.flip();
+            RENDER_BACKEND.uniform4(locs[LOC_FOG_COLOR], vec4Buf);
+        }
+
+        // Alpha test reference — core profile replacement for GL_ALPHA_TEST
+        // Return -1.0f for ALWAYS or disabled so `alpha <= ref` never discards.
+        if (locs[LOC_ALPHA_TEST_REF] != -1) {
+            final float ref;
+            if (!GLStateManager.getAlphaTest().isEnabled() || GLStateManager.getAlphaState().getFunction() == GL11.GL_ALWAYS) {
+                ref = -1.0f;
+            } else {
+                ref = GLStateManager.getAlphaState().getReference();
+            }
+            RENDER_BACKEND.uniform1f(locs[LOC_ALPHA_TEST_REF], ref);
+        }
+    }
+
+    /**
+     * Scene color = emission + ambient * lightModel.ambient, alpha = diffuse.a Same computation as {@code Uniforms.uploadLightingPreComputed()}.
+     */
+    private static void uploadSceneColor(int[] locs) {
+        final MaterialState mat = GLStateManager.getFrontMaterial();
+        final LightModelState lm = GLStateManager.getLightModel();
+        vec4Buf.clear();
+        vec4Buf.put(mat.emission.x + mat.ambient.x * lm.ambient.x)
+               .put(mat.emission.y + mat.ambient.y * lm.ambient.y)
+               .put(mat.emission.z + mat.ambient.z * lm.ambient.z)
+               .put(mat.diffuse.w);
+        vec4Buf.flip();
+        RENDER_BACKEND.uniform4(locs[LOC_SCENE_COLOR], vec4Buf);
+    }
+
+    private static void uploadLightSources(int[] locs) {
+        // Early exit: if the first light field isn't present, no lighting uniforms exist
+        if (locs[LOC_LIGHT_BASE] == -1) return;
+        final LightStateStack[] lights = GLStateManager.getLightDataStates();
+        for (int li = 0; li < 2; li++) {
+            final int base = LOC_LIGHT_BASE + li * LIGHT_FIELDS;
+            final LightState light = lights[li];
+
+            if (locs[base + LF_AMBIENT] != -1)
+                RENDER_BACKEND.uniform4f(locs[base + LF_AMBIENT], light.ambient.x, light.ambient.y, light.ambient.z, light.ambient.w);
+            if (locs[base + LF_DIFFUSE] != -1)
+                RENDER_BACKEND.uniform4f(locs[base + LF_DIFFUSE], light.diffuse.x, light.diffuse.y, light.diffuse.z, light.diffuse.w);
+            if (locs[base + LF_SPECULAR] != -1)
+                RENDER_BACKEND.uniform4f(locs[base + LF_SPECULAR], light.specular.x, light.specular.y, light.specular.z, light.specular.w);
+            if (locs[base + LF_POSITION] != -1)
+                RENDER_BACKEND.uniform4f(locs[base + LF_POSITION], light.position.x, light.position.y, light.position.z, light.position.w);
+            if (locs[base + LF_HALF_VECTOR] != -1) {
+                // halfVector = normalize(normalize(position.xyz) + eye), eye=(0,0,1) for infinite viewer
+                float hx, hy, hz;
+                if (light.position.w == 0.0f) {
+                    final float len = (float) Math.sqrt(light.position.x * light.position.x
+                            + light.position.y * light.position.y
+                            + light.position.z * light.position.z);
+                    if (len > 0) {
+                        hx = light.position.x / len;
+                        hy = light.position.y / len;
+                        hz = light.position.z / len + 1.0f;
+                    } else {
+                        hx = 0; hy = 0; hz = 1;
+                    }
+                } else {
+                    hx = 0; hy = 0; hz = 1;
+                }
+                final float hlen = (float) Math.sqrt(hx * hx + hy * hy + hz * hz);
+                if (hlen > 0) { hx /= hlen; hy /= hlen; hz /= hlen; }
+                RENDER_BACKEND.uniform4f(locs[base + LF_HALF_VECTOR], hx, hy, hz, 0.0f);
+            }
+            if (locs[base + LF_SPOT_DIRECTION] != -1) RENDER_BACKEND.uniform3f(locs[base + LF_SPOT_DIRECTION], light.spotDirection.x, light.spotDirection.y, light.spotDirection.z);
+            if (locs[base + LF_SPOT_EXPONENT] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_SPOT_EXPONENT], light.spotExponent);
+            if (locs[base + LF_SPOT_CUTOFF] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_SPOT_CUTOFF], light.spotCutoff);
+            if (locs[base + LF_SPOT_COS_CUTOFF] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_SPOT_COS_CUTOFF], light.spotCosCutoff);
+            if (locs[base + LF_CONSTANT_ATTEN] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_CONSTANT_ATTEN], light.constantAttenuation);
+            if (locs[base + LF_LINEAR_ATTEN] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_LINEAR_ATTEN], light.linearAttenuation);
+            if (locs[base + LF_QUADRATIC_ATTEN] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_QUADRATIC_ATTEN], light.quadraticAttenuation);
+        }
+    }
+
+    private static void uploadMaterial(int[] locs) {
+        // Early exit: if the first material field isn't present, no material uniforms exist
+        if (locs[LOC_MAT_BASE] == -1) return;
+        final MaterialState mat = GLStateManager.getFrontMaterial();
+        if (locs[LOC_MAT_BASE + MF_EMISSION] != -1)
+            RENDER_BACKEND.uniform4f(locs[LOC_MAT_BASE + MF_EMISSION], mat.emission.x, mat.emission.y, mat.emission.z, mat.emission.w);
+        if (locs[LOC_MAT_BASE + MF_AMBIENT] != -1)
+            RENDER_BACKEND.uniform4f(locs[LOC_MAT_BASE + MF_AMBIENT], mat.ambient.x, mat.ambient.y, mat.ambient.z, mat.ambient.w);
+        if (locs[LOC_MAT_BASE + MF_DIFFUSE] != -1)
+            RENDER_BACKEND.uniform4f(locs[LOC_MAT_BASE + MF_DIFFUSE], mat.diffuse.x, mat.diffuse.y, mat.diffuse.z, mat.diffuse.w);
+        if (locs[LOC_MAT_BASE + MF_SPECULAR] != -1)
+            RENDER_BACKEND.uniform4f(locs[LOC_MAT_BASE + MF_SPECULAR], mat.specular.x, mat.specular.y, mat.specular.z, mat.specular.w);
+        if (locs[LOC_MAT_BASE + MF_SHININESS] != -1)
+            RENDER_BACKEND.uniform1f(locs[LOC_MAT_BASE + MF_SHININESS], mat.shininess);
+    }
+
+    private static void uploadClipPlanes(int[] locs) {
+        if (locs[LOC_CLIP_PLANES_ENABLED] != -1) {
+            RENDER_BACKEND.uniform1i(locs[LOC_CLIP_PLANES_ENABLED], GLStateManager.anyClipPlaneEnabled() ? 1 : 0);
+        }
+        if (locs[LOC_CLIP_PLANES] != -1) {
+            final ClipPlaneState cps = GLStateManager.getClipPlaneState();
+            clipPlaneBuf.clear();
+            for (int i = 0; i < GLStateManager.MAX_CLIP_PLANES; i++) {
+                cps.putEyePlane(i, clipPlaneBuf);
+            }
+            clipPlaneBuf.flip();
+            RENDER_BACKEND.uniform4(locs[LOC_CLIP_PLANES], clipPlaneBuf);
+        }
+    }
+
+    public static void onDeleteProgram(int program) {
+        programUniforms.remove(program);
+    }
+
+    public static boolean hasProgram(int program) {
+        return programUniforms.containsKey(program);
+    }
+
+    public static int[] getLocations(int program) {
+        final ProgramUniforms pu = programUniforms.get(program);
+        return pu == null ? null : pu.locs;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/DisplayListIDAllocator.java

@@ -0,0 +1,187 @@
+package com.gtnewhorizons.angelica.glsm;
+
+/*
+ * Ported from Mesa's util_idalloc (src/util/u_idalloc.c).
+ *
+ * Original copyright and license:
+ *
+ * Copyright 2017 Valve Corporation
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Original author: Samuel Pitoiset <[email protected]>
+ */
+
+/**
+ * Bitmap ID allocator for display list IDs.
+ *
+ * <p>Bitmap-based: each bit in the {@code data} array represents one ID.
+ * Bit set = allocated, bit clear = free. ID 0 is reserved (never returned).
+ */
+public class DisplayListIDAllocator {
+
+    private int[] data;
+    private int numElements;       // number of uint32 words allocated
+    private int numSetElements;    // highest word index with any bit set + 1
+    private int lowestFreeIdx;     // optimization: skip fully-allocated words
+
+    public DisplayListIDAllocator() {
+        this(32); // 1024 IDs initially
+    }
+
+    public DisplayListIDAllocator(int initialWords) {
+        if (initialWords < 1) initialWords = 1;
+        this.data = new int[initialWords];
+        this.numElements = initialWords;
+        this.numSetElements = 0;
+        this.lowestFreeIdx = 0;
+        // Reserve ID 0 (never returned), matching Mesa's skip_zero pattern
+        data[0] = 1;
+        numSetElements = 1;
+    }
+
+    public int allocRange(int count) {
+        if (count <= 0) throw new IllegalArgumentException("count must be > 0");
+        if (count == 1) return allocSingle();
+        return allocMultiple(count);
+    }
+
+    private int allocSingle() {
+        for (int i = lowestFreeIdx; i < numElements; i++) {
+            if (data[i] == 0xFFFFFFFF) continue;
+
+            int bit = Integer.numberOfTrailingZeros(~data[i]);
+            data[i] |= 1 << bit;
+            lowestFreeIdx = i;
+            numSetElements = Math.max(numSetElements, i + 1);
+            return i * 32 + bit;
+        }
+
+        // No slots available, grow. Record old end, then mark first bit there.
+        int oldNumElements = numElements;
+        resize(Math.max(numElements, 1) * 2);
+        lowestFreeIdx = oldNumElements;
+        data[oldNumElements] |= 1;
+        numSetElements = Math.max(numSetElements, oldNumElements + 1);
+        return oldNumElements * 32;
+    }
+
+    private int allocMultiple(int num) {
+        int numWords = divRoundUp(num, 32);
+        int base = findFreeBlock(lowestFreeIdx);
+        boolean found = false;
+
+        while (!found) {
+            int i;
+            for (i = base; i < numElements && i - base < numWords && data[i] == 0; i++)
+                ;
+
+            if (i - base == numWords) {
+                found = true;
+            } else if (i == numElements) {
+                // Hit end — base is valid: data[base..end] are zero, resize extends the run into newly zeroed words.
+                resize(numElements * 2 + numWords);
+                found = true;
+            } else {
+                // Non-zero word at i, skip past it
+                base = i + 1;
+            }
+        }
+
+        // Mark bits as used
+        int fullWords = num / 32;
+        int remainder = num % 32;
+        for (int i = base; i < base + fullWords; i++) {
+            data[i] = 0xFFFFFFFF;
+        }
+        if (remainder != 0) {
+            data[base + fullWords] |= (1 << remainder) - 1;
+        }
+
+        if (lowestFreeIdx == base) {
+            lowestFreeIdx = base + num / 32;
+        }
+        numSetElements = Math.max(numSetElements, base + numWords);
+
+        return base * 32;
+    }
+
+    private int findFreeBlock(int start) {
+        for (int i = start; i < numElements; i++) {
+            if (data[i] == 0) return i;
+        }
+        return numElements;
+    }
+
+    public void free(int id) {
+        if (id <= 0) return; // ID 0 is reserved
+        int idx = id / 32;
+        if (idx >= numElements) return;
+
+        lowestFreeIdx = Math.min(idx, lowestFreeIdx);
+        data[idx] &= ~(1 << (id % 32));
+
+        if (numSetElements == idx + 1) {
+            while (numSetElements > 0 && data[numSetElements - 1] == 0) {
+                numSetElements--;
+            }
+        }
+    }
+
+    public void freeRange(int base, int count) {
+        if (count <= 0 || base <= 0) return;
+
+        int startIdx = base / 32;
+        if (startIdx >= numElements) return;
+
+        int end = base + count;
+        for (int id = base; id < end; id++) {
+            int idx = id / 32;
+            if (idx >= numElements) break;
+            data[idx] &= ~(1 << (id % 32));
+        }
+
+        lowestFreeIdx = Math.min(startIdx, lowestFreeIdx);
+        while (numSetElements > 0 && data[numSetElements - 1] == 0) {
+            numSetElements--;
+        }
+    }
+
+    public boolean isAllocated(int id) {
+        if (id <= 0) return false;
+        int idx = id / 32;
+        if (idx >= numSetElements) return false;
+        return (data[idx] & (1 << (id % 32))) != 0;
+    }
+
+    private void resize(int newNumElements) {
+        if (newNumElements <= numElements) return;
+        int[] newData = new int[newNumElements];
+        System.arraycopy(data, 0, newData, 0, numElements);
+        data = newData;
+        numElements = newNumElements;
+    }
+
+    private static int divRoundUp(int a, int b) {
+        return (a + b - 1) / b;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/Feature.java

@@ -2,14 +2,18 @@ package com.gtnewhorizons.angelica.glsm;
 
 import com.google.common.collect.ImmutableSet;
 import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
+import com.gtnewhorizons.angelica.glsm.ffp.ShaderManager;
+import com.gtnewhorizons.angelica.glsm.stacks.BooleanStateStack;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL13;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -19,45 +23,85 @@ public class Feature {
         GL13.GL_MULTISAMPLE_BIT, GL11.GL_PIXEL_MODE_BIT, GL11.GL_POINT_BIT, GL11.GL_POLYGON_BIT, GL11.GL_POLYGON_STIPPLE_BIT, GL11.GL_SCISSOR_BIT,
         GL11.GL_STENCIL_BUFFER_BIT, GL11.GL_TEXTURE_BIT, GL11.GL_TRANSFORM_BIT, GL11.GL_VIEWPORT_BIT };
 
-    static final Int2ObjectMap<Set<IStateStack<?>>> maskToFeaturesMap = new Int2ObjectOpenHashMap<>();
+    static final Int2ObjectMap<List<IStateStack<?>>> maskToFeaturesMap = new Int2ObjectOpenHashMap<>();
+    static final Int2ObjectMap<IStateStack<?>[]> maskToNonBooleanStacksMap = new Int2ObjectOpenHashMap<>();
 
-    static Set<IStateStack<?>> maskToFeatures(int mask) {
+    static List<IStateStack<?>> maskToFeatures(int mask) {
         if(maskToFeaturesMap.containsKey(mask)) {
             return maskToFeaturesMap.get(mask);
         }
 
         final Set<IStateStack<?>> features = new HashSet<>();
+
         for(int attrib : Feature.supportedAttribs) {
             if((mask & attrib) == attrib) {
                 features.addAll(getFeatures(attrib));
             }
         }
-        maskToFeaturesMap.put(mask, features);
-        return features;
+
+        final List<IStateStack<?>> asList = new ArrayList<>(features);
+
+        maskToFeaturesMap.put(mask, asList);
+        return asList;
+    }
+
+    /**
+     * Returns only non-BooleanStateStack instances for the given mask.
+     * These use traditional push/pop without global depth tracking.
+     */
+    static IStateStack<?>[] maskToNonBooleanStacks(int mask) {
+        IStateStack<?>[] cached = maskToNonBooleanStacksMap.get(mask);
+        if (cached != null) {
+            return cached;
+        }
+
+        final List<IStateStack<?>> all = maskToFeatures(mask);
+        final List<IStateStack<?>> nonBooleans = new ArrayList<>();
+        for (int i = 0; i < all.size(); i++) {
+            final IStateStack<?> stack = all.get(i);
+            if (!(stack instanceof BooleanStateStack)) {
+                nonBooleans.add(stack);
+            }
+        }
+        cached = nonBooleans.toArray(new IStateStack<?>[0]);
+        maskToNonBooleanStacksMap.put(mask, cached);
+        return cached;
     }
 
     private static final Map<Integer, Set<IStateStack<?>>> attribToFeatures = new HashMap<>();
+
+    /**
+     * Helper method to add all texture gen states (S, T, R, Q) for all texture units to a collection.
+     * Used by both GL_ENABLE_BIT and GL_TEXTURE_BIT.
+     */
+    private static void addTextureGenStates(Set<IStateStack<?>> collection) {
+        for(int i = 0 ; i < GLStateManager.MAX_TEXTURE_UNITS; i++) {
+            collection.add(GLStateManager.textures.getTexGenSStates(i));
+            collection.add(GLStateManager.textures.getTexGenTStates(i));
+            collection.add(GLStateManager.textures.getTexGenRStates(i));
+            collection.add(GLStateManager.textures.getTexGenQStates(i));
+        }
+    }
+
     static {
         attribToFeatures.put(GL11.GL_COLOR_BUFFER_BIT, ImmutableSet.of(
               GLStateManager.alphaTest  // GL_ALPHA_TEST enable bit
             , GLStateManager.alphaState // Alpha test function and reference value
             , GLStateManager.blendMode  // GL_BLEND enable bit
-            , GLStateManager.blendState // Blending source and destination functions
-            // Constant blend color
-            // Blending equation
-            // GL_DITHER enable bit
-            // GL_DRAW_BUFFER setting
-            // GL_COLOR_LOGIC_OP enable bit
-            // GL_INDEX_LOGIC_OP enable bit
-            // Logic op function
+            , GLStateManager.blendState // Blending source/destination functions, equation, blend color
+            , GLStateManager.colorLogicOpState // GL_COLOR_LOGIC_OP enable bit
+            , GLStateManager.ditherState // GL_DITHER enable bit
+            , GLStateManager.drawBuffer // GL_DRAW_BUFFER setting
+            , GLStateManager.indexLogicOpState // GL_INDEX_LOGIC_OP enable bit
+            , GLStateManager.logicOpMode // Logic op function
             , GLStateManager.colorMask   // Color-mode and index-mode writemasks
             , GLStateManager.clearColor  // Color-mode and index-mode clear values
         ));
         attribToFeatures.put(GL11.GL_CURRENT_BIT, ImmutableSet.of(
               GLStateManager.color  // Current RGBA color
+            , ShaderManager.getNormalStack()    // Current normal vector
+            , ShaderManager.getTexCoordStack()  // Current texture coordinates
             // Current color index
-            // Current normal vector
-            // Current texture coordinates
             // Current raster position
             // GL_CURRENT_RASTER_POSITION_VALID flag
             // RGBA color associated with current raster position
@@ -74,14 +118,15 @@ public class Feature {
 
         final HashSet<IStateStack<?>> enableBits = new HashSet<>(ImmutableSet.of(
               GLStateManager.alphaTest // GL_ALPHA_TEST flag
-            // GL_AUTO_NORMAL flag
+            , GLStateManager.autoNormalState // GL_AUTO_NORMAL flag
             , GLStateManager.blendMode // GL_BLEND flag
-            // Enable bits for the user-definable clipping planes
+            , GLStateManager.colorLogicOpState // GL_COLOR_LOGIC_OP flag
             , GLStateManager.colorMaterial // GL_COLOR_MATERIAL
             , GLStateManager.cullState // GL_CULL_FACE flag
             , GLStateManager.depthTest // GL_DEPTH_TEST flag
-            // GL_DITHER flag
+            , GLStateManager.ditherState // GL_DITHER flag
             , GLStateManager.fogMode // GL_FOG flag
+            , GLStateManager.indexLogicOpState // GL_INDEX_LOGIC_OP flag
             , GLStateManager.lightStates[0] // GL_LIGHT0
             , GLStateManager.lightStates[1] // GL_LIGHT1
             , GLStateManager.lightStates[2] // GL_LIGHT2
@@ -91,36 +136,57 @@ public class Feature {
             , GLStateManager.lightStates[6] // GL_LIGHT6
             , GLStateManager.lightStates[7] // GL_LIGHT7
             , GLStateManager.lightingState // GL_LIGHTING flag
-            // GL_LINE_SMOOTH flag
-            // GL_LINE_STIPPLE flag
-            // GL_INDEX_LOGIC_OP flag
-            // GL_COLOR_LOGIC_OP flag
-            // GL_MAP1_x where x is a map type
-            // GL_MAP2_x where x is a map type
-            // GL_MULTISAMPLE flag
-            // GL_NORMALIZE flag
-            // GL_POINT_SMOOTH flag
-            // GL_POLYGON_OFFSET_LINE flag
-            // GL_POLYGON_OFFSET_FILL flag
-            // GL_POLYGON_OFFSET_POINT flag
-            // GL_POLYGON_SMOOTH flag
-            // GL_POLYGON_STIPPLE flag
-            // GL_SAMPLE_ALPHA_TO_COVERAGE flag
-            // GL_SAMPLE_ALPHA_TO_ONE flag
-            // GL_SAMPLE_COVERAGE flag
+            , GLStateManager.lineSmoothState // GL_LINE_SMOOTH flag
+            , GLStateManager.lineStippleState // GL_LINE_STIPPLE flag
+            , GLStateManager.map1Color4State // GL_MAP1_COLOR_4
+            , GLStateManager.map1IndexState // GL_MAP1_INDEX
+            , GLStateManager.map1NormalState // GL_MAP1_NORMAL
+            , GLStateManager.map1TextureCoord1State // GL_MAP1_TEXTURE_COORD_1
+            , GLStateManager.map1TextureCoord2State // GL_MAP1_TEXTURE_COORD_2
+            , GLStateManager.map1TextureCoord3State // GL_MAP1_TEXTURE_COORD_3
+            , GLStateManager.map1TextureCoord4State // GL_MAP1_TEXTURE_COORD_4
+            , GLStateManager.map1Vertex3State // GL_MAP1_VERTEX_3
+            , GLStateManager.map1Vertex4State // GL_MAP1_VERTEX_4
+            , GLStateManager.map2Color4State // GL_MAP2_COLOR_4
+            , GLStateManager.map2IndexState // GL_MAP2_INDEX
+            , GLStateManager.map2NormalState // GL_MAP2_NORMAL
+            , GLStateManager.map2TextureCoord1State // GL_MAP2_TEXTURE_COORD_1
+            , GLStateManager.map2TextureCoord2State // GL_MAP2_TEXTURE_COORD_2
+            , GLStateManager.map2TextureCoord3State // GL_MAP2_TEXTURE_COORD_3
+            , GLStateManager.map2TextureCoord4State // GL_MAP2_TEXTURE_COORD_4
+            , GLStateManager.map2Vertex3State // GL_MAP2_VERTEX_3
+            , GLStateManager.map2Vertex4State // GL_MAP2_VERTEX_4
+            , GLStateManager.multisampleState // GL_MULTISAMPLE flag
+            , GLStateManager.normalizeState // GL_NORMALIZE flag
+            , GLStateManager.pointSmoothState // GL_POINT_SMOOTH flag
+            , GLStateManager.polygonOffsetPointState // GL_POLYGON_OFFSET_POINT flag
+            , GLStateManager.polygonOffsetLineState // GL_POLYGON_OFFSET_LINE flag
+            , GLStateManager.polygonOffsetFillState // GL_POLYGON_OFFSET_FILL flag
+            , GLStateManager.polygonSmoothState // GL_POLYGON_SMOOTH flag
+            , GLStateManager.polygonStippleState // GL_POLYGON_STIPPLE flag
+            , GLStateManager.rescaleNormalState // GL_RESCALE_NORMAL flag
+            , GLStateManager.sampleAlphaToCoverageState // GL_SAMPLE_ALPHA_TO_COVERAGE flag
+            , GLStateManager.sampleAlphaToOneState // GL_SAMPLE_ALPHA_TO_ONE flag
+            , GLStateManager.sampleCoverageState // GL_SAMPLE_COVERAGE flag
             , GLStateManager.scissorTest  // GL_SCISSOR_TEST flag
-            // GL_STENCIL_TEST flag
-            // GL_TEXTURE_1D flag
-            // GL_TEXTURE_2D flag - Below
-            // GL_TEXTURE_3D flag
-            // Flags GL_TEXTURE_GEN_x where x is S, T, R, or Q
+            , GLStateManager.stencilTest // GL_STENCIL_TEST flag
         ));
 
-        // GL_TEXTURE_2D flag
-        for(int i = 0 ; i < GLStateManager.MAX_TEXTURE_UNITS; i++) {
-            enableBits.add(GLStateManager.textures.getTextureUnitStates(i));
+        // Enable bits for the user-definable clipping planes
+        for(int i = 0; i < GLStateManager.clipPlaneStates.length; i++) {
+            enableBits.add(GLStateManager.clipPlaneStates[i]);
         }
 
+        // GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D flags
+        for(int i = 0 ; i < GLStateManager.MAX_TEXTURE_UNITS; i++) {
+            enableBits.add(GLStateManager.textures.getTexture1DStates(i));
+            enableBits.add(GLStateManager.textures.getTextureUnitStates(i));
+            enableBits.add(GLStateManager.textures.getTexture3DStates(i));
+        }
+
+        // Flags GL_TEXTURE_GEN_x where x is S, T, R, or Q
+        addTextureGenStates(enableBits);
+
         attribToFeatures.put(GL11.GL_ENABLE_BIT, enableBits);
         attribToFeatures.put(GL11.GL_EVAL_BIT, ImmutableSet.of(
             // GL_MAP1_x enable bits, where x is a map type
@@ -181,10 +247,9 @@ public class Feature {
             , GLStateManager.shadeModelState // GL_SHADE_MODEL setting
         ));
         attribToFeatures.put(GL11.GL_LINE_BIT, ImmutableSet.of(
-            // GL_LINE_SMOOTH flag
-            // GL_LINE_STIPPLE enable bit
-            // Line stipple pattern and repeat counter
-            // Line width
+              GLStateManager.lineSmoothState // GL_LINE_SMOOTH flag
+            , GLStateManager.lineStippleState // GL_LINE_STIPPLE enable bit
+            , GLStateManager.lineState // Line stipple pattern, repeat counter, and width
         ));
         attribToFeatures.put(GL11.GL_LIST_BIT, ImmutableSet.of(
             // GL_LIST_BASE setting
@@ -209,21 +274,17 @@ public class Feature {
             // GL_READ_BUFFER setting
         ));
         attribToFeatures.put(GL11.GL_POINT_BIT, ImmutableSet.of(
-            // GL_POINT_SMOOTH flag
-            // Point size
+              GLStateManager.pointSmoothState // GL_POINT_SMOOTH flag
+            , GLStateManager.pointState // Point size
         ));
         attribToFeatures.put(GL11.GL_POLYGON_BIT, ImmutableSet.of(
               GLStateManager.cullState // GL_CULL_FACE enable bit
-            // GL_CULL_FACE_MODE value
-            // GL_FRONT_FACE indicator
-            // GL_POLYGON_MODE setting
-            // GL_POLYGON_SMOOTH flag
-            // GL_POLYGON_STIPPLE enable bit
-            // GL_POLYGON_OFFSET_FILL flag
-            // GL_POLYGON_OFFSET_LINE flag
-            // GL_POLYGON_OFFSET_POINT flag
-            // GL_POLYGON_OFFSET_FACTOR
-            // GL_POLYGON_OFFSET_UNITS
+            , GLStateManager.polygonSmoothState // GL_POLYGON_SMOOTH flag
+            , GLStateManager.polygonStippleState // GL_POLYGON_STIPPLE enable bit
+            , GLStateManager.polygonOffsetFillState // GL_POLYGON_OFFSET_FILL flag
+            , GLStateManager.polygonOffsetLineState // GL_POLYGON_OFFSET_LINE flag
+            , GLStateManager.polygonOffsetPointState // GL_POLYGON_OFFSET_POINT flag
+            , GLStateManager.polygonState // GL_CULL_FACE_MODE, GL_FRONT_FACE, GL_POLYGON_MODE, GL_POLYGON_OFFSET_FACTOR/UNITS
         ));
         attribToFeatures.put(GL11.GL_POLYGON_STIPPLE_BIT, ImmutableSet.of(
             // Polygon stipple pattern
@@ -233,15 +294,12 @@ public class Feature {
             // Scissor box
         ));
         attribToFeatures.put(GL11.GL_STENCIL_BUFFER_BIT, ImmutableSet.of(
-            // GL_STENCIL_TEST enable bit
-            // Stencil function and reference value
-            // Stencil value mask
-            // Stencil fail, pass, and depth buffer pass actions
-            // Stencil buffer clear value
-            // Stencil buffer writemask
+              GLStateManager.stencilTest // GL_STENCIL_TEST enable bit
+            , GLStateManager.stencilState // Stencil function, ref, mask, ops, writemask, clear value
         ));
         final Set<IStateStack<?>> textureAttribs = new HashSet<>(ImmutableSet.of(
             GLStateManager.activeTextureUnit // Active texture unit
+                // GL_TEXTURE_ENV_MODE + GL_TEXTURE_ENV_COLOR — now per-unit in TexEnvState (added below)
                 // Enable bits for the four texture coordinates
 
                 // Border color for each texture image
@@ -249,26 +307,28 @@ public class Feature {
                 // Magnification function for each texture image
                 // Texture coordinates and wrap mode for each texture image
 
-                // Color and mode for each texture environment
                 // Enable bits GL_TEXTURE_GEN_x, x is S, T, R, and Q
                 // GL_TEXTURE_GEN_MODE setting for S, T, R, and Q
                 // glTexGen plane equations for S, T, R, and Q
                 // Current texture bindings (for example, GL_TEXTURE_BINDING_2D) - Below
         ));
 
-        // Current Texture Bindings - GL_TEXTURE_BINDING_2D
+        // Current Texture Bindings - GL_TEXTURE_BINDING_2D + per-unit TexEnvState
         for(int i = 0 ; i < GLStateManager.MAX_TEXTURE_UNITS; i++) {
             textureAttribs.add(GLStateManager.textures.getTextureUnitBindings(i));
-//            textureAttribs.add(GLStateManager.textures.getInfo(i))
+            textureAttribs.add(GLStateManager.textures.getTexEnvState(i));
         }
 
+        // Enable bits GL_TEXTURE_GEN_x where x is S, T, R, or Q
+        addTextureGenStates(textureAttribs);
+
         attribToFeatures.put(GL11.GL_TEXTURE_BIT, textureAttribs);
 
         attribToFeatures.put(GL11.GL_TRANSFORM_BIT, ImmutableSet.of(
             // Coefficients of the six clipping planes
             // Enable bits for the user-definable clipping planes
               GLStateManager.matrixMode
-            // GL_NORMALIZE flag
+            , GLStateManager.normalizeState // GL_NORMALIZE flag
             , GLStateManager.rescaleNormalState // GL_RESCALE_NORMAL flag
         ));
         attribToFeatures.put(GL11.GL_VIEWPORT_BIT, ImmutableSet.of(

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/FeedbackManager.java

@@ -0,0 +1,397 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.ffp.VAOManager;
+import com.gtnewhorizons.angelica.glsm.recording.ImmediateModeRecorder;
+import com.gtnewhorizons.angelica.glsm.states.ViewportState;
+import org.joml.Matrix4f;
+import org.joml.Vector4f;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+import java.nio.ShortBuffer;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * Software emulation of GL feedback mode
+ */
+public class FeedbackManager {
+
+    private static final int FB_3D = 0x01;
+    private static final int FB_4D = 0x02;
+    private static final int FB_COLOR = 0x04;
+    private static final int FB_TEXTURE = 0x08;
+
+    private static int renderMode = GL11.GL_RENDER;
+    private static FloatBuffer feedbackBuffer;
+    private static int feedbackBufferSize;
+    private static int feedbackMask;
+    private static int feedbackCount;
+
+    private static final Matrix4f mvpMatrix = new Matrix4f();
+    private static final Vector4f clipVec = new Vector4f();
+
+    private static ByteBuffer readbackBuf = ByteBuffer.allocateDirect(256 * 1024).order(ByteOrder.nativeOrder());
+    private static ByteBuffer indexReadbackBuf = ByteBuffer.allocateDirect(4 * 1024).order(ByteOrder.nativeOrder());
+
+    @FunctionalInterface
+    private interface IndexReader {
+
+        int read(int i);
+    }
+
+    public static boolean isFeedbackMode() {
+        return renderMode == GL11.GL_FEEDBACK;
+    }
+
+    public static void glFeedbackBuffer(int type, FloatBuffer buffer) {
+        if (renderMode == GL11.GL_FEEDBACK) {
+            GLStateManager.LOGGER.error("glFeedbackBuffer called while already in feedback mode");
+            return;
+        }
+        feedbackBuffer = buffer;
+        feedbackBufferSize = buffer.remaining();
+        feedbackMask = computeMask(type);
+        feedbackCount = 0;
+    }
+
+    public static int glRenderMode(int mode) {
+        int result = switch (renderMode) {
+            case GL11.GL_FEEDBACK -> (feedbackCount > feedbackBufferSize) ? -1 : feedbackCount;
+            case GL11.GL_RENDER, GL11.GL_SELECT -> 0;
+            default -> 0;
+        };
+
+        if (mode == GL11.GL_SELECT) {
+            GLStateManager.LOGGER.warn("glRenderMode(GL_SELECT): selection mode not emulated");
+        }
+
+        feedbackCount = 0;
+        renderMode = mode;
+        return result;
+    }
+
+    public static void glPassThrough(float token) {
+        if (renderMode == GL11.GL_FEEDBACK) {
+            feedbackToken(GL11.GL_PASS_THROUGH_TOKEN);
+            feedbackToken(token);
+        }
+    }
+
+    private static void feedbackToken(float token) {
+        if (feedbackCount < feedbackBufferSize) {
+            feedbackBuffer.put(feedbackBuffer.position() + feedbackCount, token);
+        }
+        feedbackCount++;
+    }
+
+    private static void feedbackVertex(float winX, float winY, float winZ, float winW) {
+        feedbackToken(winX);
+        feedbackToken(winY);
+        if ((feedbackMask & FB_3D) != 0) feedbackToken(winZ);
+        if ((feedbackMask & FB_4D) != 0) feedbackToken(winW);
+        if ((feedbackMask & FB_COLOR) != 0) {
+            feedbackToken(1f);
+            feedbackToken(1f);
+            feedbackToken(1f);
+            feedbackToken(1f);
+        }
+        if ((feedbackMask & FB_TEXTURE) != 0) {
+            feedbackToken(0f);
+            feedbackToken(0f);
+            feedbackToken(0f);
+            feedbackToken(1f);
+        }
+    }
+
+    private static void transformAndEmitVertex(float x, float y, float z) {
+        clipVec.set(x, y, z, 1.0f);
+        mvpMatrix.transform(clipVec);
+
+        final float w = clipVec.w;
+        final float ndcX = clipVec.x / w;
+        final float ndcY = clipVec.y / w;
+        final float ndcZ = clipVec.z / w;
+
+        final ViewportState vp = GLStateManager.getViewportState();
+        final float winX = vp.x + vp.width * (ndcX + 1.0f) * 0.5f;
+        final float winY = vp.y + vp.height * (ndcY + 1.0f) * 0.5f;
+        final float winZ = (float) ((vp.depthRangeFar - vp.depthRangeNear) * ndcZ + (vp.depthRangeFar + vp.depthRangeNear)) * 0.5f;
+        final float winW = 1.0f / w;
+
+        feedbackVertex(winX, winY, winZ, winW);
+    }
+
+    private static int positionStride() {
+        final int s = VAOManager.getAttribEffectiveStride(0);
+        return (s != 0) ? s : 12;
+    }
+
+    private static long positionOffset() {
+        return VAOManager.getAttribOffset(0);
+    }
+
+    public static void processDrawArrays(int mode, int first, int count) {
+        computeMVP();
+        final int stride = positionStride();
+        final long posOffset = positionOffset();
+        final int byteCount = count * stride;
+        ensureReadbackCapacity(byteCount);
+        readbackBuf.clear().limit(byteCount);
+        readPositionBuffer((long) first * stride + posOffset, readbackBuf);
+
+        emitAllPrimitives(mode, count, i -> i, stride);
+    }
+
+    public static void processDrawElements(int mode, int indexCount, int type, long eboOffset) {
+        computeMVP();
+        final int stride = positionStride();
+
+        final int elementSize = VAOManager.Attrib.glTypeSizeBytes(type);
+        final int indexByteCount = indexCount * elementSize;
+        ensureIndexReadbackCapacity(indexByteCount);
+        indexReadbackBuf.clear().limit(indexByteCount);
+        RENDER_BACKEND.getBufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, eboOffset, indexReadbackBuf);
+        final ByteBuffer indexBuf = indexReadbackBuf;
+
+        int minIdx = Integer.MAX_VALUE, maxIdx = Integer.MIN_VALUE;
+        for (int i = 0; i < indexCount; i++) {
+            final int idx = ImmediateModeRecorder.readIndex(indexBuf, type, 0, i);
+            if (idx < minIdx) minIdx = idx;
+            if (idx > maxIdx) maxIdx = idx;
+        }
+
+        final long posOffset = positionOffset();
+        final int vertexCount = maxIdx - minIdx + 1;
+        final int byteCount = vertexCount * stride;
+        ensureReadbackCapacity(byteCount);
+        readbackBuf.clear().limit(byteCount);
+        readPositionBuffer((long) minIdx * stride + posOffset, readbackBuf);
+
+        final int base = minIdx;
+        emitAllPrimitives(mode, indexCount, i -> ImmediateModeRecorder.readIndex(indexBuf, type, 0, i) - base, stride);
+    }
+
+    public static void processDrawElements(int mode, ByteBuffer indices) {
+        final int basePos = indices.position();
+        processDrawElementsImpl(mode, indices.remaining(), i -> indices.get(basePos + i) & 0xFF);
+    }
+
+    public static void processDrawElements(int mode, ShortBuffer indices) {
+        final int basePos = indices.position();
+        processDrawElementsImpl(mode, indices.remaining(), i -> indices.get(basePos + i) & 0xFFFF);
+    }
+
+    public static void processDrawElements(int mode, IntBuffer indices) {
+        final int basePos = indices.position();
+        processDrawElementsImpl(mode, indices.remaining(), i -> indices.get(basePos + i));
+    }
+
+    public static void processDrawElements(int mode, int count, int type, ByteBuffer indices) {
+        final int pos = indices.position();
+        final IndexReader reader = switch (type) {
+            case GL11.GL_UNSIGNED_BYTE -> i -> indices.get(pos + i) & 0xFF;
+            case GL11.GL_UNSIGNED_SHORT -> i -> indices.getShort(pos + i * 2) & 0xFFFF;
+            case GL11.GL_UNSIGNED_INT -> i -> indices.getInt(pos + i * 4);
+            default -> i -> 0;
+        };
+        processDrawElementsImpl(mode, count, reader);
+    }
+
+    private static void processDrawElementsImpl(int mode, int count, IndexReader reader) {
+        computeMVP();
+        final int stride = positionStride();
+
+        int minIdx = Integer.MAX_VALUE, maxIdx = Integer.MIN_VALUE;
+        for (int i = 0; i < count; i++) {
+            final int idx = reader.read(i);
+            if (idx < minIdx) minIdx = idx;
+            if (idx > maxIdx) maxIdx = idx;
+        }
+
+        readVerticesFromVBO(minIdx, maxIdx, stride);
+        final int base = minIdx;
+        emitAllPrimitives(mode, count, i -> reader.read(i) - base, stride);
+    }
+
+    private static void computeMVP() {
+        mvpMatrix.set(GLStateManager.getProjectionMatrix()).mul(GLStateManager.getModelViewMatrix());
+    }
+
+    private static int computeMask(int type) {
+        return switch (type) {
+            case GL11.GL_2D -> 0;
+            case GL11.GL_3D -> FB_3D;
+            case GL11.GL_3D_COLOR -> FB_3D | FB_COLOR;
+            case GL11.GL_3D_COLOR_TEXTURE -> FB_3D | FB_COLOR | FB_TEXTURE;
+            case GL11.GL_4D_COLOR_TEXTURE -> FB_3D | FB_4D | FB_COLOR | FB_TEXTURE;
+            default -> 0;
+        };
+    }
+
+    private static void ensureReadbackCapacity(int bytes) {
+        if (readbackBuf.capacity() < bytes) {
+            readbackBuf = ByteBuffer.allocateDirect(bytes).order(ByteOrder.nativeOrder());
+        }
+    }
+
+    private static void ensureIndexReadbackCapacity(int bytes) {
+        if (indexReadbackBuf.capacity() < bytes) {
+            indexReadbackBuf = ByteBuffer.allocateDirect(bytes).order(ByteOrder.nativeOrder());
+        }
+    }
+
+    private static void readVerticesFromVBO(int minIdx, int maxIdx, int stride) {
+        final long posOffset = positionOffset();
+        final int vertexCount = maxIdx - minIdx + 1;
+        final int byteCount = vertexCount * stride;
+        ensureReadbackCapacity(byteCount);
+        readbackBuf.clear().limit(byteCount);
+        readPositionBuffer((long) minIdx * stride + posOffset, readbackBuf);
+    }
+
+    private static void readPositionBuffer(long offset, ByteBuffer destination) {
+        final int positionVbo = VAOManager.getAttribVBO(0);
+        final int previousVbo = GLStateManager.getBoundVBO();
+
+        if (positionVbo != 0 && positionVbo != previousVbo) {
+            GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, positionVbo);
+        }
+        try {
+            RENDER_BACKEND.getBufferSubData(GL15.GL_ARRAY_BUFFER, offset, destination);
+        } finally {
+            if (positionVbo != 0 && positionVbo != previousVbo) {
+                GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, previousVbo);
+            }
+        }
+    }
+
+    private static void emitVertex(int vertexIndex, int stride) {
+        final float x = readbackBuf.getFloat(vertexIndex * stride);
+        final float y = readbackBuf.getFloat(vertexIndex * stride + 4);
+        final float z = readbackBuf.getFloat(vertexIndex * stride + 8);
+        transformAndEmitVertex(x, y, z);
+    }
+
+    private static void emitAllPrimitives(int mode, int count, IndexReader reader, int stride) {
+        switch (mode) {
+            case GL11.GL_POINTS:
+                for (int i = 0; i < count; i++) {
+                    feedbackToken(GL11.GL_POINT_TOKEN);
+                    emitVertex(reader.read(i), stride);
+                }
+                break;
+
+            case GL11.GL_LINES:
+                for (int i = 0; i + 1 < count; i += 2) {
+                    feedbackToken(i == 0 ? GL11.GL_LINE_RESET_TOKEN : GL11.GL_LINE_TOKEN);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                }
+                break;
+
+            case GL11.GL_LINE_STRIP:
+                for (int i = 0; i + 1 < count; i++) {
+                    feedbackToken(i == 0 ? GL11.GL_LINE_RESET_TOKEN : GL11.GL_LINE_TOKEN);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                }
+                break;
+
+            case GL11.GL_LINE_LOOP:
+                for (int i = 0; i + 1 < count; i++) {
+                    feedbackToken(i == 0 ? GL11.GL_LINE_RESET_TOKEN : GL11.GL_LINE_TOKEN);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                }
+                if (count > 2) {
+                    feedbackToken(GL11.GL_LINE_TOKEN);
+                    emitVertex(reader.read(count - 1), stride);
+                    emitVertex(reader.read(0), stride);
+                }
+                break;
+
+            case GL11.GL_TRIANGLES:
+                for (int i = 0; i + 2 < count; i += 3) {
+                    feedbackToken(GL11.GL_POLYGON_TOKEN);
+                    feedbackToken(3);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                    emitVertex(reader.read(i + 2), stride);
+                }
+                break;
+
+            case GL11.GL_TRIANGLE_STRIP:
+                for (int i = 0; i + 2 < count; i++) {
+                    feedbackToken(GL11.GL_POLYGON_TOKEN);
+                    feedbackToken(3);
+                    if ((i & 1) == 0) {
+                        emitVertex(reader.read(i), stride);
+                        emitVertex(reader.read(i + 1), stride);
+                    } else {
+                        emitVertex(reader.read(i + 1), stride);
+                        emitVertex(reader.read(i), stride);
+                    }
+                    emitVertex(reader.read(i + 2), stride);
+                }
+                break;
+
+            case GL11.GL_TRIANGLE_FAN:
+                for (int i = 1; i + 1 < count; i++) {
+                    feedbackToken(GL11.GL_POLYGON_TOKEN);
+                    feedbackToken(3);
+                    emitVertex(reader.read(0), stride);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                }
+                break;
+
+            case GL11.GL_QUADS:
+                for (int i = 0; i + 3 < count; i += 4) {
+                    feedbackToken(GL11.GL_POLYGON_TOKEN);
+                    feedbackToken(4);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                    emitVertex(reader.read(i + 2), stride);
+                    emitVertex(reader.read(i + 3), stride);
+                }
+                break;
+
+            case GL11.GL_QUAD_STRIP:
+                for (int i = 0; i + 3 < count; i += 2) {
+                    feedbackToken(GL11.GL_POLYGON_TOKEN);
+                    feedbackToken(4);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                    emitVertex(reader.read(i + 3), stride);
+                    emitVertex(reader.read(i + 2), stride);
+                }
+                break;
+
+            case GL11.GL_POLYGON:
+                if (count >= 3) {
+                    feedbackToken(GL11.GL_POLYGON_TOKEN);
+                    feedbackToken(count);
+                    for (int i = 0; i < count; i++) {
+                        emitVertex(reader.read(i), stride);
+                    }
+                }
+                break;
+
+            default:
+                throw new UnsupportedOperationException("Feedback mode: unsupported primitive mode 0x" + Integer.toHexString(mode));
+        }
+    }
+
+    static void reset() {
+        renderMode = GL11.GL_RENDER;
+        feedbackBuffer = null;
+        feedbackBufferSize = 0;
+        feedbackMask = 0;
+        feedbackCount = 0;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/GLDebug.java

@@ -0,0 +1,600 @@
+/*
+ * Copyright LWJGL. All rights reserved. Modified by IMS for use in Iris (net.coderbot.iris.gl).
+ * License terms: https://www.lwjgl.org/license
+ */
+
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.backend.BackendManager;
+import org.lwjgl.opengl.EXTBlendColor;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL12;
+import org.lwjgl.opengl.GL13;
+import org.lwjgl.opengl.GL14;
+import org.lwjgl.opengl.GL30;
+import org.lwjgl.opengl.GL43;
+
+public final class GLDebug {
+
+    /**
+     * Sets up debug callbacks
+     *
+     * @return 0 for failure, 1 for success, 2 for restart required.
+     */
+    public static int setupDebugMessageCallback() {
+        if (Thread.currentThread() != GLStateManager.getMainThread()) {
+            GLStateManager.LOGGER.warn("setupDebugMessageCallback called from non-main thread!");
+            return 0;
+        }
+        return setupDebugMessageCallbackImpl();
+    }
+
+    public static Throwable filterStackTrace(Throwable throwable, int offset) {
+        final StackTraceElement[] elems = throwable.getStackTrace();
+        final StackTraceElement[] filtered = new StackTraceElement[elems.length];
+        int j = 0;
+        for (int i = offset; i < elems.length; i++) {
+            String className = elems[i].getClassName();
+            if (className == null) {
+                className = "";
+            }
+            filtered[j++] = elems[i];
+        }
+        final StackTraceElement[] newElems = new StackTraceElement[j];
+        System.arraycopy(filtered, 0, newElems, 0, j);
+        throwable.setStackTrace(newElems);
+        return throwable;
+    }
+
+    private static String buildStackTrace() {
+        final StackTraceElement[] elems = filterStackTrace(new Throwable(), 4).getStackTrace();
+        final StringBuilder sb = new StringBuilder();
+        for (StackTraceElement elem : elems) {
+            sb.append("\n\t").append(elem.toString());
+        }
+        return sb.toString();
+    }
+
+    private static void logDebugMessage(int id, String source, String type, String severity, String message) {
+        final String fullMessage = String.format("[GL] %s %s (0x%X) from %s: %s%s", severity, type, id, source, message, buildStackTrace());
+
+        if ("HIGH".equals(severity)) {
+            GLStateManager.LOGGER.error(fullMessage);
+        } else if ("MEDIUM".equals(severity)) {
+            GLStateManager.LOGGER.warn(fullMessage);
+        } else {
+            GLStateManager.LOGGER.info(fullMessage);
+        }
+    }
+
+    private static int setupDebugMessageCallbackImpl() {
+        return BackendManager.RENDER_BACKEND.setupDebugOutput(
+            (source, type, id, severity, message) ->
+                logDebugMessage(id, getDebugSource(source), getDebugType(type), getDebugSeverity(severity), message)
+        );
+    }
+
+    public static int disableDebugMessages() {
+        return BackendManager.RENDER_BACKEND.disableDebugOutput();
+    }
+
+    private static String getDebugSource(int source) {
+        return switch (source) {
+            case GL43.GL_DEBUG_SOURCE_API -> "API";
+            case GL43.GL_DEBUG_SOURCE_WINDOW_SYSTEM -> "WINDOW SYSTEM";
+            case GL43.GL_DEBUG_SOURCE_SHADER_COMPILER -> "SHADER COMPILER";
+            case GL43.GL_DEBUG_SOURCE_THIRD_PARTY -> "THIRD PARTY";
+            case GL43.GL_DEBUG_SOURCE_APPLICATION -> "APPLICATION";
+            case GL43.GL_DEBUG_SOURCE_OTHER -> "OTHER";
+            default -> String.format("Unknown [0x%X]", source);
+        };
+    }
+
+    private static String getDebugType(int type) {
+        return switch (type) {
+            case GL43.GL_DEBUG_TYPE_ERROR -> "ERROR";
+            case GL43.GL_DEBUG_TYPE_DEPRECATED_BEHAVIOR -> "DEPRECATED BEHAVIOR";
+            case GL43.GL_DEBUG_TYPE_UNDEFINED_BEHAVIOR -> "UNDEFINED BEHAVIOR";
+            case GL43.GL_DEBUG_TYPE_PORTABILITY -> "PORTABILITY";
+            case GL43.GL_DEBUG_TYPE_PERFORMANCE -> "PERFORMANCE";
+            case GL43.GL_DEBUG_TYPE_OTHER -> "OTHER";
+            case GL43.GL_DEBUG_TYPE_MARKER -> "MARKER";
+            default -> String.format("Unknown [0x%X]", type);
+        };
+    }
+
+    private static String getDebugSeverity(int severity) {
+        return switch (severity) {
+            case GL43.GL_DEBUG_SEVERITY_NOTIFICATION -> "NOTIFICATION";
+            case GL43.GL_DEBUG_SEVERITY_HIGH -> "HIGH";
+            case GL43.GL_DEBUG_SEVERITY_MEDIUM -> "MEDIUM";
+            case GL43.GL_DEBUG_SEVERITY_LOW -> "LOW";
+            default -> String.format("Unknown [0x%X]", severity);
+        };
+    }
+
+    public static String getMatrixModeName(int mode) {
+        return switch (mode) {
+            case GL11.GL_MODELVIEW -> "MODELVIEW";
+            case GL11.GL_PROJECTION -> "PROJECTION";
+            case GL11.GL_TEXTURE -> "TEXTURE";
+            case GL11.GL_COLOR -> "COLOR";
+            default -> String.format("0x%X", mode);
+        };
+    }
+
+    public static String getCapabilityName(int cap) {
+        return switch (cap) {
+            case GL11.GL_ALPHA_TEST -> "ALPHA_TEST";
+            case GL11.GL_BLEND -> "BLEND";
+            case GL11.GL_COLOR_MATERIAL -> "COLOR_MATERIAL";
+            case GL11.GL_CULL_FACE -> "CULL_FACE";
+            case GL11.GL_DEPTH_TEST -> "DEPTH_TEST";
+            case GL11.GL_FOG -> "FOG";
+            case GL11.GL_LIGHTING -> "LIGHTING";
+            case GL11.GL_LINE_SMOOTH -> "LINE_SMOOTH";
+            case GL11.GL_NORMALIZE -> "NORMALIZE";
+            case GL11.GL_POINT_SMOOTH -> "POINT_SMOOTH";
+            case GL11.GL_POLYGON_OFFSET_FILL -> "POLYGON_OFFSET_FILL";
+            case GL11.GL_POLYGON_OFFSET_LINE -> "POLYGON_OFFSET_LINE";
+            case GL11.GL_POLYGON_SMOOTH -> "POLYGON_SMOOTH";
+            case GL12.GL_RESCALE_NORMAL -> "RESCALE_NORMAL";
+            case GL11.GL_SCISSOR_TEST -> "SCISSOR_TEST";
+            case GL11.GL_STENCIL_TEST -> "STENCIL_TEST";
+            case GL11.GL_TEXTURE_1D -> "TEXTURE_1D";
+            case GL11.GL_TEXTURE_2D -> "TEXTURE_2D";
+            case GL11.GL_LIGHT0 -> "LIGHT0";
+            case GL11.GL_LIGHT1 -> "LIGHT1";
+            case GL11.GL_LIGHT2 -> "LIGHT2";
+            case GL11.GL_LIGHT3 -> "LIGHT3";
+            case GL11.GL_LIGHT4 -> "LIGHT4";
+            case GL11.GL_LIGHT5 -> "LIGHT5";
+            case GL11.GL_LIGHT6 -> "LIGHT6";
+            case GL11.GL_LIGHT7 -> "LIGHT7";
+            default -> String.format("0x%X", cap);
+        };
+    }
+
+    public static String getComparisonFuncName(int func) {
+        return switch (func) {
+            case GL11.GL_NEVER -> "NEVER";
+            case GL11.GL_LESS -> "LESS";
+            case GL11.GL_EQUAL -> "EQUAL";
+            case GL11.GL_LEQUAL -> "LEQUAL";
+            case GL11.GL_GREATER -> "GREATER";
+            case GL11.GL_NOTEQUAL -> "NOTEQUAL";
+            case GL11.GL_GEQUAL -> "GEQUAL";
+            case GL11.GL_ALWAYS -> "ALWAYS";
+            default -> String.format("0x%X", func);
+        };
+    }
+
+    public static String getBlendFactorName(int factor) {
+        return switch (factor) {
+            case GL11.GL_ZERO -> "ZERO";
+            case GL11.GL_ONE -> "ONE";
+            case GL11.GL_SRC_COLOR -> "SRC_COLOR";
+            case GL11.GL_ONE_MINUS_SRC_COLOR -> "ONE_MINUS_SRC_COLOR";
+            case GL11.GL_DST_COLOR -> "DST_COLOR";
+            case GL11.GL_ONE_MINUS_DST_COLOR -> "ONE_MINUS_DST_COLOR";
+            case GL11.GL_SRC_ALPHA -> "SRC_ALPHA";
+            case GL11.GL_ONE_MINUS_SRC_ALPHA -> "ONE_MINUS_SRC_ALPHA";
+            case GL11.GL_DST_ALPHA -> "DST_ALPHA";
+            case GL11.GL_ONE_MINUS_DST_ALPHA -> "ONE_MINUS_DST_ALPHA";
+            case EXTBlendColor.GL_CONSTANT_COLOR_EXT -> "CONSTANT_COLOR";
+            case EXTBlendColor.GL_ONE_MINUS_CONSTANT_COLOR_EXT -> "ONE_MINUS_CONSTANT_COLOR";
+            case EXTBlendColor.GL_CONSTANT_ALPHA_EXT -> "CONSTANT_ALPHA";
+            case EXTBlendColor.GL_ONE_MINUS_CONSTANT_ALPHA_EXT -> "ONE_MINUS_CONSTANT_ALPHA";
+            case GL11.GL_SRC_ALPHA_SATURATE -> "SRC_ALPHA_SATURATE";
+            default -> String.format("0x%X", factor);
+        };
+    }
+
+    public static String getShadeModelName(int mode) {
+        return switch (mode) {
+            case GL11.GL_FLAT -> "FLAT";
+            case GL11.GL_SMOOTH -> "SMOOTH";
+            default -> String.format("0x%X", mode);
+        };
+    }
+
+    public static String getTextureTargetName(int target) {
+        return switch (target) {
+            case GL11.GL_TEXTURE_1D -> "TEXTURE_1D";
+            case GL11.GL_TEXTURE_2D -> "TEXTURE_2D";
+            case GL12.GL_TEXTURE_3D -> "TEXTURE_3D";
+            case GL13.GL_TEXTURE_CUBE_MAP -> "TEXTURE_CUBE_MAP";
+            default -> String.format("0x%X", target);
+        };
+    }
+
+    public static String getTexturePnameName(int pname) {
+        return switch (pname) {
+            case GL11.GL_TEXTURE_MIN_FILTER -> "TEXTURE_MIN_FILTER";
+            case GL11.GL_TEXTURE_MAG_FILTER -> "TEXTURE_MAG_FILTER";
+            case GL11.GL_TEXTURE_WRAP_S -> "TEXTURE_WRAP_S";
+            case GL11.GL_TEXTURE_WRAP_T -> "TEXTURE_WRAP_T";
+            case GL12.GL_TEXTURE_WRAP_R -> "TEXTURE_WRAP_R";
+            case GL12.GL_TEXTURE_MIN_LOD -> "TEXTURE_MIN_LOD";
+            case GL12.GL_TEXTURE_MAX_LOD -> "TEXTURE_MAX_LOD";
+            case GL12.GL_TEXTURE_BASE_LEVEL -> "TEXTURE_BASE_LEVEL";
+            case GL12.GL_TEXTURE_MAX_LEVEL -> "TEXTURE_MAX_LEVEL";
+            case GL11.GL_TEXTURE_BORDER_COLOR -> "TEXTURE_BORDER_COLOR";
+            case GL11.GL_TEXTURE_PRIORITY -> "TEXTURE_PRIORITY";
+            case GL14.GL_TEXTURE_LOD_BIAS -> "TEXTURE_LOD_BIAS";
+            case GL14.GL_GENERATE_MIPMAP -> "GENERATE_MIPMAP";
+            default -> String.format("0x%X", pname);
+        };
+    }
+
+    public static String getTextureFormatName(int format) {
+        return switch (format) {
+            case GL11.GL_RED -> "RED";
+            case GL11.GL_GREEN -> "GREEN";
+            case GL11.GL_BLUE -> "BLUE";
+            case GL11.GL_ALPHA -> "ALPHA";
+            case GL11.GL_RGB -> "RGB";
+            case GL11.GL_RGBA -> "RGBA";
+            case GL11.GL_LUMINANCE -> "LUMINANCE";
+            case GL11.GL_LUMINANCE_ALPHA -> "LUMINANCE_ALPHA";
+            case GL12.GL_BGR -> "BGR";
+            case GL12.GL_BGRA -> "BGRA";
+            case GL11.GL_DEPTH_COMPONENT -> "DEPTH_COMPONENT";
+            case GL11.GL_STENCIL_INDEX -> "STENCIL_INDEX";
+            case GL30.GL_DEPTH_STENCIL -> "DEPTH_STENCIL";
+            // Internal formats
+            case GL11.GL_RGB8 -> "RGB8";
+            case GL11.GL_RGBA8 -> "RGBA8";
+            case GL11.GL_ALPHA8 -> "ALPHA8";
+            case GL11.GL_LUMINANCE8 -> "LUMINANCE8";
+            case GL11.GL_LUMINANCE8_ALPHA8 -> "LUMINANCE8_ALPHA8";
+            default -> String.format("0x%X", format);
+        };
+    }
+
+    public static String getDataTypeName(int type) {
+        return switch (type) {
+            case GL11.GL_UNSIGNED_BYTE -> "UNSIGNED_BYTE";
+            case GL11.GL_BYTE -> "BYTE";
+            case GL11.GL_UNSIGNED_SHORT -> "UNSIGNED_SHORT";
+            case GL11.GL_SHORT -> "SHORT";
+            case GL11.GL_UNSIGNED_INT -> "UNSIGNED_INT";
+            case GL11.GL_INT -> "INT";
+            case GL11.GL_FLOAT -> "FLOAT";
+            case GL11.GL_DOUBLE -> "DOUBLE";
+            case GL12.GL_UNSIGNED_BYTE_3_3_2 -> "UNSIGNED_BYTE_3_3_2";
+            case GL12.GL_UNSIGNED_SHORT_4_4_4_4 -> "UNSIGNED_SHORT_4_4_4_4";
+            case GL12.GL_UNSIGNED_SHORT_5_5_5_1 -> "UNSIGNED_SHORT_5_5_5_1";
+            case GL12.GL_UNSIGNED_INT_8_8_8_8 -> "UNSIGNED_INT_8_8_8_8";
+            case GL12.GL_UNSIGNED_INT_10_10_10_2 -> "UNSIGNED_INT_10_10_10_2";
+            default -> String.format("0x%X", type);
+        };
+    }
+
+    public static String getLightName(int light) {
+        return switch (light) {
+            case GL11.GL_LIGHT0 -> "LIGHT0";
+            case GL11.GL_LIGHT1 -> "LIGHT1";
+            case GL11.GL_LIGHT2 -> "LIGHT2";
+            case GL11.GL_LIGHT3 -> "LIGHT3";
+            case GL11.GL_LIGHT4 -> "LIGHT4";
+            case GL11.GL_LIGHT5 -> "LIGHT5";
+            case GL11.GL_LIGHT6 -> "LIGHT6";
+            case GL11.GL_LIGHT7 -> "LIGHT7";
+            default -> String.format("0x%X", light);
+        };
+    }
+
+    public static String getLightPnameName(int pname) {
+        return switch (pname) {
+            case GL11.GL_AMBIENT -> "AMBIENT";
+            case GL11.GL_DIFFUSE -> "DIFFUSE";
+            case GL11.GL_SPECULAR -> "SPECULAR";
+            case GL11.GL_POSITION -> "POSITION";
+            case GL11.GL_SPOT_DIRECTION -> "SPOT_DIRECTION";
+            case GL11.GL_SPOT_EXPONENT -> "SPOT_EXPONENT";
+            case GL11.GL_SPOT_CUTOFF -> "SPOT_CUTOFF";
+            case GL11.GL_CONSTANT_ATTENUATION -> "CONSTANT_ATTENUATION";
+            case GL11.GL_LINEAR_ATTENUATION -> "LINEAR_ATTENUATION";
+            case GL11.GL_QUADRATIC_ATTENUATION -> "QUADRATIC_ATTENUATION";
+            default -> String.format("0x%X", pname);
+        };
+    }
+
+    public static String getMaterialPnameName(int pname) {
+        return switch (pname) {
+            case GL11.GL_AMBIENT -> "AMBIENT";
+            case GL11.GL_DIFFUSE -> "DIFFUSE";
+            case GL11.GL_SPECULAR -> "SPECULAR";
+            case GL11.GL_EMISSION -> "EMISSION";
+            case GL11.GL_SHININESS -> "SHININESS";
+            case GL11.GL_AMBIENT_AND_DIFFUSE -> "AMBIENT_AND_DIFFUSE";
+            case GL11.GL_COLOR_INDEXES -> "COLOR_INDEXES";
+            default -> String.format("0x%X", pname);
+        };
+    }
+
+    public static String getFaceName(int face) {
+        return switch (face) {
+            case GL11.GL_FRONT -> "FRONT";
+            case GL11.GL_BACK -> "BACK";
+            case GL11.GL_FRONT_AND_BACK -> "FRONT_AND_BACK";
+            default -> String.format("0x%X", face);
+        };
+    }
+
+    public static String getColorMaterialModeName(int mode) {
+        return switch (mode) {
+            case GL11.GL_AMBIENT -> "AMBIENT";
+            case GL11.GL_DIFFUSE -> "DIFFUSE";
+            case GL11.GL_SPECULAR -> "SPECULAR";
+            case GL11.GL_EMISSION -> "EMISSION";
+            case GL11.GL_AMBIENT_AND_DIFFUSE -> "AMBIENT_AND_DIFFUSE";
+            default -> String.format("0x%X", mode);
+        };
+    }
+
+    public static String getFogPnameName(int pname) {
+        return switch (pname) {
+            case GL11.GL_FOG_MODE -> "FOG_MODE";
+            case GL11.GL_FOG_DENSITY -> "FOG_DENSITY";
+            case GL11.GL_FOG_START -> "FOG_START";
+            case GL11.GL_FOG_END -> "FOG_END";
+            case GL11.GL_FOG_INDEX -> "FOG_INDEX";
+            case GL11.GL_FOG_COLOR -> "FOG_COLOR";
+            default -> String.format("0x%X", pname);
+        };
+    }
+
+    public static String getLightModelPnameName(int pname) {
+        return switch (pname) {
+            case GL11.GL_LIGHT_MODEL_AMBIENT -> "LIGHT_MODEL_AMBIENT";
+            case GL11.GL_LIGHT_MODEL_LOCAL_VIEWER -> "LIGHT_MODEL_LOCAL_VIEWER";
+            case GL11.GL_LIGHT_MODEL_TWO_SIDE -> "LIGHT_MODEL_TWO_SIDE";
+            case GL12.GL_LIGHT_MODEL_COLOR_CONTROL -> "LIGHT_MODEL_COLOR_CONTROL";
+            default -> String.format("0x%X", pname);
+        };
+    }
+
+    public static String getClearMaskString(int mask) {
+        StringBuilder sb = new StringBuilder();
+        boolean first = true;
+        if ((mask & GL11.GL_COLOR_BUFFER_BIT) != 0) {
+            sb.append("COLOR");
+            first = false;
+        }
+        if ((mask & GL11.GL_DEPTH_BUFFER_BIT) != 0) {
+            if (!first) sb.append("|");
+            sb.append("DEPTH");
+            first = false;
+        }
+        if ((mask & GL11.GL_STENCIL_BUFFER_BIT) != 0) {
+            if (!first) sb.append("|");
+            sb.append("STENCIL");
+            first = false;
+        }
+        if ((mask & GL11.GL_ACCUM_BUFFER_BIT) != 0) {
+            if (!first) sb.append("|");
+            sb.append("ACCUM");
+        }
+        return sb.toString();
+    }
+
+    public static String getCullFaceName(int mode) {
+        return switch (mode) {
+            case GL11.GL_FRONT -> "FRONT";
+            case GL11.GL_BACK -> "BACK";
+            case GL11.GL_FRONT_AND_BACK -> "FRONT_AND_BACK";
+            default -> String.format("0x%X", mode);
+        };
+    }
+
+    public static String getLogicOpName(int opcode) {
+        return switch (opcode) {
+            case GL11.GL_CLEAR -> "CLEAR";
+            case GL11.GL_AND -> "AND";
+            case GL11.GL_AND_REVERSE -> "AND_REVERSE";
+            case GL11.GL_COPY -> "COPY";
+            case GL11.GL_AND_INVERTED -> "AND_INVERTED";
+            case GL11.GL_NOOP -> "NOOP";
+            case GL11.GL_XOR -> "XOR";
+            case GL11.GL_OR -> "OR";
+            case GL11.GL_NOR -> "NOR";
+            case GL11.GL_EQUIV -> "EQUIV";
+            case GL11.GL_INVERT -> "INVERT";
+            case GL11.GL_OR_REVERSE -> "OR_REVERSE";
+            case GL11.GL_COPY_INVERTED -> "COPY_INVERTED";
+            case GL11.GL_OR_INVERTED -> "OR_INVERTED";
+            case GL11.GL_NAND -> "NAND";
+            case GL11.GL_SET -> "SET";
+            default -> String.format("0x%X", opcode);
+        };
+    }
+
+    public static String getFramebufferStatusName(int status) {
+        return switch (status) {
+            case GL30.GL_FRAMEBUFFER_COMPLETE -> "COMPLETE";
+            case GL30.GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT -> "INCOMPLETE_ATTACHMENT";
+            case GL30.GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT -> "INCOMPLETE_MISSING_ATTACHMENT";
+            case GL30.GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER -> "INCOMPLETE_DRAW_BUFFER";
+            case GL30.GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER -> "INCOMPLETE_READ_BUFFER";
+            case GL30.GL_FRAMEBUFFER_UNSUPPORTED -> "UNSUPPORTED";
+            case GL30.GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE -> "INCOMPLETE_MULTISAMPLE";
+            case 0 -> "NO_FRAMEBUFFER_BOUND";
+            default -> String.format("UNKNOWN(0x%X)", status);
+        };
+    }
+
+    public static String getInternalFormatName(int format) {
+        return switch (format) {
+            // Basic
+            case GL11.GL_RGBA -> "RGBA";
+            case GL11.GL_RGB -> "RGB";
+            // 8-bit normalized
+            case GL30.GL_R8 -> "R8";
+            case GL30.GL_RG8 -> "RG8";
+            case GL11.GL_RGB8 -> "RGB8";
+            case GL11.GL_RGBA8 -> "RGBA8";
+            // 8-bit signed normalized
+            case 0x8F94 -> "R8_SNORM";
+            case 0x8F95 -> "RG8_SNORM";
+            case 0x8F96 -> "RGB8_SNORM";
+            case 0x8F97 -> "RGBA8_SNORM";
+            // 16-bit normalized
+            case GL30.GL_R16 -> "R16";
+            case GL30.GL_RG16 -> "RG16";
+            case GL11.GL_RGB16 -> "RGB16";
+            case GL11.GL_RGBA16 -> "RGBA16";
+            // 16-bit float
+            case GL30.GL_R16F -> "R16F";
+            case GL30.GL_RG16F -> "RG16F";
+            case GL30.GL_RGB16F -> "RGB16F";
+            case GL30.GL_RGBA16F -> "RGBA16F";
+            // 32-bit float
+            case GL30.GL_R32F -> "R32F";
+            case GL30.GL_RG32F -> "RG32F";
+            case GL30.GL_RGB32F -> "RGB32F";
+            case GL30.GL_RGBA32F -> "RGBA32F";
+            // Packed
+            case GL30.GL_R11F_G11F_B10F -> "R11F_G11F_B10F";
+            case GL11.GL_RGB10_A2 -> "RGB10_A2";
+            default -> String.format("0x%X", format);
+        };
+    }
+
+    private static DebugState debugState;
+
+    private interface DebugState {
+
+        void nameObject(int id, int object, String name);
+
+        void pushGroup(String name);
+
+        void popGroup();
+
+        void debugMessage(String name);
+
+        String getObjectLabel(int glProgram, int program);
+    }
+
+    private static class KHRDebugState implements DebugState {
+
+        private static final int ID = 0;
+        private int depth = 0;
+        private static final int maxDepth = BackendManager.RENDER_BACKEND.getInteger(GL43.GL_MAX_DEBUG_GROUP_STACK_DEPTH);
+        private final String[] groupStack = new String[maxDepth + 1];
+
+        @Override
+        public void nameObject(int id, int object, String name) {
+            BackendManager.RENDER_BACKEND.objectLabel(id, object, name);
+        }
+
+        @Override
+        public void pushGroup(String name) {
+            if (depth + 1 > maxDepth) {
+                final StringBuilder sb = new StringBuilder();
+                sb.append("Debug group stack overflow (maxDepth=").append(maxDepth).append("), current stack:\n");
+                for (int i = 0; i < depth; i++) {
+                    sb.append("  [").append(i).append("] ").append(groupStack[i]).append('\n');
+                }
+                sb.append("  -> ").append(name).append(" (rejected)");
+                throw new RuntimeException(sb.toString());
+            }
+            groupStack[depth] = name;
+            BackendManager.RENDER_BACKEND.pushDebugGroup(GL43.GL_DEBUG_SOURCE_APPLICATION, ID, name);
+            depth++;
+        }
+
+        @Override
+        public void popGroup() {
+            if (depth - 1 < 0) {
+                throw new RuntimeException("Stack underflow");
+            }
+            BackendManager.RENDER_BACKEND.popDebugGroup();
+            depth--;
+            groupStack[depth] = null;
+        }
+
+        @Override
+        public void debugMessage(String message) {
+            BackendManager.RENDER_BACKEND.debugMessageInsert(
+                    GL43.GL_DEBUG_SOURCE_APPLICATION,
+                    GL43.GL_DEBUG_TYPE_MARKER,
+                    ID,
+                    GL43.GL_DEBUG_SEVERITY_NOTIFICATION,
+                    message);
+        }
+
+        @Override
+        public String getObjectLabel(int glProgram, int program) {
+            if (program == 0) return "";
+
+            return BackendManager.RENDER_BACKEND.getObjectLabel(glProgram, program);
+        }
+    }
+
+    private static class UnsupportedDebugState implements DebugState {
+
+        @Override
+        public void nameObject(int id, int object, String name) {
+        }
+
+        @Override
+        public void pushGroup(String name) {
+        }
+
+        @Override
+        public void popGroup() {
+        }
+
+        @Override
+        public void debugMessage(String name) {
+
+        }
+
+        @Override
+        public String getObjectLabel(int glProgram, int program) {
+            return "";
+        }
+    }
+
+    public static void initDebugState() {
+        if (BackendManager.RENDER_BACKEND.supportsDebugOutput()) {
+            debugState = new KHRDebugState();
+        } else {
+            debugState = new UnsupportedDebugState();
+        }
+    }
+
+    public static void nameObject(int id, int object, String name) {
+        if (debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
+            debugState.nameObject(id, object, name);
+        }
+    }
+
+    public static void pushGroup(String group) {
+        if (debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
+            debugState.pushGroup(group);
+        }
+    }
+
+    public static void popGroup() {
+        if (debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
+            debugState.popGroup();
+        }
+    }
+
+    public static void debugMessage(String message) {
+        if (debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
+            debugState.debugMessage(message);
+        }
+    }
+
+    public static String getObjectLabel(int glProgram, int program) {
+        if (debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
+            return debugState.getObjectLabel(glProgram, program);
+        }
+        return "";
+    }
+
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/GlslTransformUtils.java

@@ -0,0 +1,120 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import org.antlr.v4.runtime.tree.ParseTree;
+import org.antlr.v4.runtime.tree.TerminalNode;
+
+import java.util.List;
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Shared GLSL shader transformation utilities.
+ */
+public class GlslTransformUtils {
+
+    private static final String RENAMED_PREFIX = "angelica_renamed_";
+
+    /** Texture function renames */
+    public static final Map<String, String> TEXTURE_RENAMES = Map.ofEntries(
+        Map.entry("texture2D", "texture"),
+        Map.entry("texture3D", "texture"),
+        Map.entry("texture2DLod", "textureLod"),
+        Map.entry("texture3DLod", "textureLod"),
+        Map.entry("texture2DProj", "textureProj"),
+        Map.entry("texture3DProj", "textureProj"),
+        Map.entry("texture2DGrad", "textureGrad"),
+        Map.entry("texture2DGradARB", "textureGrad"),
+        Map.entry("texture3DGrad", "textureGrad"),
+        Map.entry("texelFetch2D", "texelFetch"),
+        Map.entry("texelFetch3D", "texelFetch"),
+        Map.entry("textureSize2D", "textureSize")
+    );
+
+    private static final Pattern TEXTURE_PATTERN = Pattern.compile("\\btexture\\s*\\(|(\\btexture\\b)");
+
+    /** Reserved words added in later GLSL versions that may appear as identifiers in older shaders. */
+    private record ReservedWordRename(Pattern pattern, String replacement) {}
+    private static final Map<Integer, List<ReservedWordRename>> VERSIONED_RESERVED_WORDS = Map.of(
+        // Some reserved words to always rename
+        0, List.of(
+            new ReservedWordRename(Pattern.compile("\\bsample\\b"), RENAMED_PREFIX + "sample"),
+            new ReservedWordRename(Pattern.compile("\\bnew\\b"), RENAMED_PREFIX + "new")
+        ),
+        400, List.of(
+            new ReservedWordRename(Pattern.compile("\\bsampler\\b(?!\\d)"), RENAMED_PREFIX + "sampler")
+        )
+    );
+
+    public static String replaceTexture(String input) {
+        final Matcher matcher = TEXTURE_PATTERN.matcher(input);
+        final StringBuilder builder = new StringBuilder();
+        while (matcher.find()) {
+            if (matcher.group(1) != null) {
+                matcher.appendReplacement(builder, RENAMED_PREFIX + "texture");
+            } else {
+                matcher.appendReplacement(builder, Matcher.quoteReplacement(matcher.group(0)));
+            }
+        }
+        matcher.appendTail(builder);
+        return builder.toString();
+    }
+
+    public static String renameReservedWords(String source, int targetVersion) {
+        for (var entry : VERSIONED_RESERVED_WORDS.entrySet()) {
+            // Rename identifiers that become reserved words at or above this GLSL version
+            if (targetVersion >= entry.getKey()) {
+                for (var rename : entry.getValue()) {
+                    source = rename.pattern().matcher(source).replaceAll(rename.replacement());
+                }
+            }
+        }
+        return source;
+    }
+
+    public static String restoreReservedWords(String source) {
+        source = source.replace(RENAMED_PREFIX + "texture", "texture");
+        source = source.replace(RENAMED_PREFIX + "sampler", "sampler");
+        source = source.replace(RENAMED_PREFIX + "sample", "sample");
+        return source;
+    }
+
+    public static String getFormattedShader(ParseTree tree, String header) {
+        final StringBuilder sb = new StringBuilder(header + "\n");
+        final String[] tabHolder = {""};
+        getFormattedShader(tree, sb, tabHolder);
+        return sb.toString();
+    }
+
+    private static void getFormattedShader(ParseTree tree, StringBuilder stringBuilder, String[] tabHolder) {
+        if (tree instanceof TerminalNode) {
+            final String text = tree.getText();
+            if (text.equals("<EOF>")) {
+                return;
+            }
+            if (text.equals("#")) {
+                stringBuilder.append("\n#");
+                return;
+            }
+            stringBuilder.append(text);
+            if (text.equals("{")) {
+                stringBuilder.append(" \n\t");
+                tabHolder[0] = "\t";
+            }
+
+            if (text.equals("}")) {
+                if (stringBuilder.length() >= 2) {
+                    stringBuilder.deleteCharAt(stringBuilder.length() - 2);
+                }
+                tabHolder[0] = "";
+                stringBuilder.append(" \n");
+            } else {
+                stringBuilder.append(text.equals(";") ? " \n" + tabHolder[0] : " ");
+            }
+        } else {
+            for (int i = 0; i < tree.getChildCount(); ++i) {
+                getFormattedShader(tree.getChild(i), stringBuilder, tabHolder);
+            }
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/QuadConverter.java

@@ -0,0 +1,390 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.ffp.VAOManager;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+import java.nio.IntBuffer;
+import java.nio.ShortBuffer;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAddress0;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAlloc;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memFree;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetByte;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetInt;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetShort;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutInt;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutShort;
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * Shared quad-to-triangle EBO for core profile GL_QUADS emulation.
+ *
+ * <p>Maintains a single growable element buffer with pre-computed indices mapping
+ * GL_QUADS vertex order to GL_TRIANGLES: {@code (0,1,3, 1,2,3)} per quad.
+ * Uses {@code GL_LAST_VERTEX_CONVENTION} winding (Mesa {@code do_quad} LAST path)
+ * so both emitted triangles share the quad's provoking vertex (v3).
+ */
+public final class QuadConverter {
+    public static final int INDEX_TYPE = GL11.GL_UNSIGNED_INT;
+
+    private static int eboId;
+    private static int maxQuads;
+
+    /** Scratch EBO for converted quad-element draws (drawQuadElementsAsTriangles). */
+    private static int scratchEboId;
+    private static int scratchEboCapacity; // in bytes
+
+    private QuadConverter() {}
+
+    private static void ensureCapacity(int quadCount) {
+        if (quadCount <= maxQuads) return;
+
+        // Round up to power of 2 for amortized growth
+        int newMaxQuads = Math.max(256, maxQuads);
+        while (newMaxQuads < quadCount) {
+            newMaxQuads *= 2;
+        }
+
+        if (eboId == 0) {
+            eboId = RENDER_BACKEND.genBuffers();
+        }
+
+        // Generate index data: 6 ints per quad
+        final ByteBuffer indexData = memAlloc(newMaxQuads * 6 * 4);
+        long ptr = memAddress0(indexData);
+        for (int i = 0; i < newMaxQuads; i++) {
+            final int base = i * 4;
+            // GL_LAST_VERTEX_CONVENTION: both triangles share v3 as provoking vertex
+            // Triangle 1: 0, 1, 3
+            memPutInt(ptr, base);
+            memPutInt(ptr + 4, base + 1);
+            memPutInt(ptr + 8, base + 3);
+            // Triangle 2: 1, 2, 3
+            memPutInt(ptr + 12, base + 1);
+            memPutInt(ptr + 16, base + 2);
+            memPutInt(ptr + 20, base + 3);
+            ptr += 24;
+        }
+
+        RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, eboId);
+        RENDER_BACKEND.bufferData(GL15.GL_ELEMENT_ARRAY_BUFFER, indexData, GL15.GL_STATIC_DRAW);
+
+        memFree(indexData);
+        maxQuads = newMaxQuads;
+    }
+
+    /**
+     * Convert a GL_QUADS glDrawArrays call to indexed GL_TRIANGLES.
+     * Binds the shared EBO to the current VAO and issues glDrawElements.
+     *
+     * @param first       first vertex index (must be aligned to quad boundary, i.e. multiple of 4)
+     * @param vertexCount number of vertices (must be multiple of 4)
+     */
+    public static void drawQuadsAsTriangles(int first, int vertexCount) {
+        drawSharedQuadEbo(first, vertexCount, 1, false);
+    }
+
+    public static void drawQuadsAsTrianglesInstanced(int first, int vertexCount, int primcount) {
+        drawSharedQuadEbo(first, vertexCount, primcount, true);
+    }
+
+    private static void drawSharedQuadEbo(int first, int vertexCount, int primcount, boolean instanced) {
+        final boolean locked = GLStateManager.acquireDrawLock();
+        try {
+            GLStateManager.preDraw();
+            assert first % 4 == 0 : "QuadConverter: first (" + first + ") must be a multiple of 4";
+            assert vertexCount % 4 == 0 : "QuadConverter: vertexCount (" + vertexCount + ") must be a multiple of 4";
+            final int quadCount = vertexCount / 4;
+            final int prevEbo = GLStateManager.getBoundEBO();
+            ensureCapacity(first / 4 + quadCount);
+            RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, eboId);
+            // Index offset: first vertex / 4 quads * 6 indices * 4 bytes per int
+            final long indexOffset = (long) (first / 4) * 6 * 4;
+            if (instanced) {
+                RENDER_BACKEND.drawElementsInstanced(GL11.GL_TRIANGLES, quadCount * 6, INDEX_TYPE, indexOffset, primcount);
+            } else {
+                RENDER_BACKEND.drawElements(GL11.GL_TRIANGLES, quadCount * 6, INDEX_TYPE, indexOffset);
+            }
+            RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEbo);
+        } finally {
+            if (locked) GLStateManager.releaseDrawLock();
+        }
+    }
+
+    /**
+     * Upload converted triangle indices to the scratch EBO and draw.
+     * Saves/restores the caller's EBO binding so subsequent indexed draws
+     * (or glGetBufferSubData reads) still see the original EBO.
+     *
+     * @param dst            off-heap buffer with triangle index data (freed by this method)
+     * @param triIndexCount  number of triangle indices
+     * @param indexType       GL_UNSIGNED_INT or GL_UNSIGNED_SHORT
+     * @param bytesPerIndex  bytes per index element
+     */
+    private static void uploadAndDraw(ByteBuffer dst, int triIndexCount, int indexType, int bytesPerIndex) {
+        uploadAndDraw(dst, triIndexCount, indexType, bytesPerIndex, 1, false);
+    }
+
+    private static void uploadAndDraw(ByteBuffer dst, int triIndexCount, int indexType, int bytesPerIndex, int primcount, boolean instanced) {
+        final boolean locked = GLStateManager.acquireDrawLock();
+        try {
+            GLStateManager.preDraw();
+            final int needed = triIndexCount * bytesPerIndex;
+            final int prevEbo = GLStateManager.getBoundEBO();
+
+            if (scratchEboId == 0) {
+                scratchEboId = RENDER_BACKEND.genBuffers();
+            }
+
+            RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, scratchEboId);
+
+            if (needed > scratchEboCapacity) {
+                // Power-of-2 growth -- allocate full capacity, upload actual data
+                int newCap = Math.max(4096, scratchEboCapacity);
+                while (newCap < needed) newCap *= 2;
+                RENDER_BACKEND.bufferData(GL15.GL_ELEMENT_ARRAY_BUFFER, newCap, GL15.GL_STREAM_DRAW);
+                scratchEboCapacity = newCap;
+            }
+            RENDER_BACKEND.bufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, 0, dst);
+
+            if (instanced) {
+                RENDER_BACKEND.drawElementsInstanced(GL11.GL_TRIANGLES, triIndexCount, indexType, 0L, primcount);
+            } else {
+                RENDER_BACKEND.drawElements(GL11.GL_TRIANGLES, triIndexCount, indexType, 0L);
+            }
+
+            RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEbo);
+        } finally {
+            if (locked) GLStateManager.releaseDrawLock();
+        }
+        memFree(dst);
+    }
+
+    /**
+     * Convert an indexed GL_QUADS draw to GL_TRIANGLES by reading the source EBO,
+     * building a triangle index buffer, and issuing the converted draw.
+     *
+     * @param indexCount number of quad indices (must be multiple of 4)
+     * @param type       GL_UNSIGNED_INT, GL_UNSIGNED_SHORT, or GL_UNSIGNED_BYTE
+     * @param offset     byte offset into the currently bound EBO
+     */
+    public static void drawQuadElementsAsTriangles(int indexCount, int type, long offset) {
+        drawQuadElementsFromEbo(indexCount, type, offset, 1, false);
+    }
+
+    public static void drawQuadElementsAsTrianglesInstanced(int indexCount, int type, long offset, int primcount) {
+        drawQuadElementsFromEbo(indexCount, type, offset, primcount, true);
+    }
+
+    private static void drawQuadElementsFromEbo(int indexCount, int type, long offset, int primcount, boolean instanced) {
+        if (indexCount == 0) return;
+        assert indexCount % 4 == 0 : "QuadConverter: indexCount must be multiple of 4";
+        final int quadCount = indexCount / 4;
+        final int triIndexCount = quadCount * 6;
+
+        final int bytesPerIndex = VAOManager.Attrib.glTypeSizeBytes(type);
+
+        final ByteBuffer src = memAlloc(indexCount * bytesPerIndex);
+        RENDER_BACKEND.getBufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, offset, src);
+
+        final ByteBuffer dst = memAlloc(triIndexCount * 4);
+        triangulateQuads(memAddress0(src), type, memAddress0(dst), GL11.GL_UNSIGNED_INT, quadCount);
+
+        memFree(src);
+        uploadAndDraw(dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4, primcount, instanced);
+    }
+
+    /**
+     * Convert a client-side IntBuffer of quad indices to triangles.
+     */
+    public static void drawQuadElementsAsTriangles(IntBuffer indices) {
+        final int indexCount = indices.remaining();
+        if (indexCount == 0) return;
+        assert indexCount % 4 == 0;
+        final int quadCount = indexCount / 4;
+        final int triIndexCount = quadCount * 6;
+
+        final ByteBuffer dst = memAlloc(triIndexCount * 4);
+        final long srcAddr = memAddress0(indices) + (long) indices.position() * 4;
+        triangulateQuads(srcAddr, GL11.GL_UNSIGNED_INT, memAddress0(dst), GL11.GL_UNSIGNED_INT, quadCount);
+
+        uploadAndDraw(dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4);
+    }
+
+    /**
+     * Convert a client-side ShortBuffer of quad indices to triangles.
+     */
+    public static void drawQuadElementsAsTriangles(ShortBuffer indices) {
+        final int indexCount = indices.remaining();
+        if (indexCount == 0) return;
+        assert indexCount % 4 == 0;
+        final int quadCount = indexCount / 4;
+        final int triIndexCount = quadCount * 6;
+
+        final ByteBuffer dst = memAlloc(triIndexCount * 2);
+        final long srcAddr = memAddress0(indices) + (long) indices.position() * 2;
+        triangulateQuads(srcAddr, GL11.GL_UNSIGNED_SHORT, memAddress0(dst), GL11.GL_UNSIGNED_SHORT, quadCount);
+
+        uploadAndDraw(dst, triIndexCount, GL11.GL_UNSIGNED_SHORT, 2);
+    }
+
+    /**
+     * Convert a client-side ByteBuffer of quad indices (type-agnostic) to triangles.
+     */
+    public static void drawQuadElementsAsTriangles(int count, int type, ByteBuffer indices) {
+        if (count == 0) return;
+        assert count % 4 == 0;
+        final int quadCount = count / 4;
+        final int triIndexCount = quadCount * 6;
+        final long srcAddr = memAddress0(indices) + indices.position();
+
+        final ByteBuffer dst = memAlloc(triIndexCount * 4);
+        triangulateQuads(srcAddr, type, memAddress0(dst), GL11.GL_UNSIGNED_INT, quadCount);
+
+        uploadAndDraw(dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4);
+    }
+
+    /**
+     * Clean up the shared EBO.
+     */
+    public static void destroy() {
+        if (eboId != 0) {
+            GLStateManager.glDeleteBuffers(eboId);
+            eboId = 0;
+            maxQuads = 0;
+        }
+        if (scratchEboId != 0) {
+            GLStateManager.glDeleteBuffers(scratchEboId);
+            scratchEboId = 0;
+            scratchEboCapacity = 0;
+        }
+    }
+
+    /**
+     * Read one index at {@code srcAddr + i * sizeof(srcType)} and return its
+     * zero-extended unsigned value.
+     */
+    private static int readIndex(long srcAddr, int srcType, int i) {
+        return switch (srcType) {
+            case GL11.GL_UNSIGNED_BYTE  -> memGetByte(srcAddr + i)          & 0xFF;
+            case GL11.GL_UNSIGNED_SHORT -> memGetShort(srcAddr + i * 2L)    & 0xFFFF;
+            case GL11.GL_UNSIGNED_INT   -> memGetInt(srcAddr + i * 4L);
+            default -> throw new IllegalArgumentException("unsupported index type 0x" + Integer.toHexString(srcType));
+        };
+    }
+
+    /**
+     * Write one index at {@code dstAddr + i * sizeof(dstType)}.
+     */
+    private static void writeIndex(long dstAddr, int dstType, int i, int value) {
+        switch (dstType) {
+            case GL11.GL_UNSIGNED_SHORT -> memPutShort(dstAddr + i * 2L, (short) value);
+            case GL11.GL_UNSIGNED_INT   -> memPutInt(dstAddr + i * 4L, value);
+            default -> throw new IllegalArgumentException("unsupported index type 0x" + Integer.toHexString(dstType));
+        }
+    }
+
+    /**
+     * Read {@code quadCount} quads from {@code srcAddr} and emit 6 triangle indices
+     * per quad at {@code dstAddr} using {@code GL_LAST_VERTEX_CONVENTION}:
+     * {@code (a,b,d), (b,c,d)}. v3 is the provoking vertex for both triangles;
+     * diagonal runs b→d. Matches Mesa's {@code do_quad} LAST path.
+     *
+     * <p>Caller allocates dst of size {@code quadCount * 6 * sizeof(dstType)}.
+     *
+     * <p>Supported src types: {@code GL_UNSIGNED_BYTE} / {@code GL_UNSIGNED_SHORT}
+     * / {@code GL_UNSIGNED_INT}. Supported dst types: {@code GL_UNSIGNED_SHORT} /
+     * {@code GL_UNSIGNED_INT}. Widening only.
+     */
+    public static void triangulateQuads(long srcAddr, int srcType, long dstAddr, int dstType, int quadCount) {
+        triangulateQuads(srcAddr, srcType, dstAddr, dstType, quadCount, 0);
+    }
+
+    /**
+     * Same as {@link #triangulateQuads(long, int, long, int, int)} but subtracts
+     * {@code minVtx} from every emitted index, rebasing to a 0-based buffer in
+     * one pass.
+     */
+    public static void triangulateQuads(long srcAddr, int srcType, long dstAddr, int dstType, int quadCount, int minVtx) {
+        for (int i = 0; i < quadCount; i++) {
+            final int a = readIndex(srcAddr, srcType, i * 4)     - minVtx;
+            final int b = readIndex(srcAddr, srcType, i * 4 + 1) - minVtx;
+            final int c = readIndex(srcAddr, srcType, i * 4 + 2) - minVtx;
+            final int d = readIndex(srcAddr, srcType, i * 4 + 3) - minVtx;
+            final int o = i * 6;
+            writeIndex(dstAddr, dstType, o,     a);
+            writeIndex(dstAddr, dstType, o + 1, b);
+            writeIndex(dstAddr, dstType, o + 2, d);
+            writeIndex(dstAddr, dstType, o + 3, b);
+            writeIndex(dstAddr, dstType, o + 4, c);
+            writeIndex(dstAddr, dstType, o + 5, d);
+        }
+    }
+
+    /**
+     * Copy {@code count} indices from {@code srcAddr} to {@code dstAddr}, converting
+     * from {@code srcType} to {@code dstType}.
+     *
+     * <p>Supported src types: {@code GL_UNSIGNED_BYTE} / {@code GL_UNSIGNED_SHORT} /
+     * {@code GL_UNSIGNED_INT}. Supported dst types: {@code GL_UNSIGNED_SHORT} /
+     * {@code GL_UNSIGNED_INT}. Widening only; narrowing is rejected by
+     * {@link #writeIndex(long, int, int, int) writeIndex}.
+     */
+    public static void widenIndices(long srcAddr, int srcType, long dstAddr, int dstType, int count) {
+        widenIndices(srcAddr, srcType, dstAddr, dstType, count, 0);
+    }
+
+    /**
+     * Same as {@link #widenIndices(long, int, long, int, int)} but subtracts
+     * {@code minVtx} from every written index in one pass.
+     */
+    public static void widenIndices(long srcAddr, int srcType, long dstAddr, int dstType, int count, int minVtx) {
+        for (int i = 0; i < count; i++) {
+            writeIndex(dstAddr, dstType, i, readIndex(srcAddr, srcType, i) - minVtx);
+        }
+    }
+
+    /**
+     * Scan {@code count} indices at {@code srcAddr} of {@code srcType}. Returns
+     * {@code (max << 32) | (min & 0xFFFFFFFFL)} or {@code -1L} for an unsupported
+     * type or empty range.
+     */
+    public static long scanMinMaxIndex(long srcAddr, int srcType, int count) {
+        if (count <= 0) return -1L;
+        long min = Long.MAX_VALUE;
+        long max = Long.MIN_VALUE;
+        switch (srcType) {
+            case GL11.GL_UNSIGNED_BYTE -> {
+                for (int i = 0; i < count; i++) {
+                    final int v = memGetByte(srcAddr + i) & 0xFF;
+                    if (v < min) min = v;
+                    if (v > max) max = v;
+                }
+            }
+            case GL11.GL_UNSIGNED_SHORT -> {
+                for (int i = 0; i < count; i++) {
+                    final int v = memGetShort(srcAddr + i * 2L) & 0xFFFF;
+                    if (v < min) min = v;
+                    if (v > max) max = v;
+                }
+            }
+            case GL11.GL_UNSIGNED_INT -> {
+                for (int i = 0; i < count; i++) {
+                    final long v = memGetInt(srcAddr + i * 4L) & 0xFFFFFFFFL;
+                    if (v < min) min = v;
+                    if (v > max) max = v;
+                }
+                // readIndex / writeIndex / rebase all route UINT through signed int.
+                // Reject the > 2^31 slice so the caller bails rather than silently
+                // emitting negative indices. MC never hits this in practice.
+                if (max > Integer.MAX_VALUE) return -1L;
+            }
+            default -> {
+                return -1L;
+            }
+        }
+        return (max << 32) | (min & 0xFFFFFFFFL);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/RenderSystem.java

@@ -0,0 +1,581 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.backend.BackendManager;
+import com.gtnewhorizons.angelica.glsm.dsa.DSAARB;
+import com.gtnewhorizons.angelica.glsm.dsa.DSAAccess;
+import com.gtnewhorizons.angelica.glsm.dsa.DSACore;
+import com.gtnewhorizons.angelica.glsm.dsa.DSAEXT;
+import com.gtnewhorizons.angelica.glsm.dsa.DSAUnsupported;
+import com.gtnewhorizons.angelica.glsm.ffp.ShaderManager;
+import com.gtnewhorizons.angelica.glsm.texture.TextureInfoCache;
+import lombok.Getter;
+import org.jetbrains.annotations.Nullable;
+import org.joml.Matrix4f;
+import org.joml.Vector3i;
+import org.lwjgl.BufferUtils;
+import org.lwjgl.opengl.ARBShaderImageLoadStore;
+import org.lwjgl.opengl.ARBShaderStorageBufferObject;
+import org.lwjgl.opengl.EXTShaderImageLoadStore;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL20;
+import org.lwjgl.opengl.GL32;
+import org.lwjgl.opengl.GL42;
+import org.lwjgl.opengl.GL43;
+import org.lwjgl.opengl.NVXGpuMemoryInfo;
+
+import java.nio.ByteBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+import java.util.Objects;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * This class is responsible for abstracting calls to OpenGL and asserting that calls are run on the render thread.
+ */
+public class RenderSystem {
+    private static DSAAccess dsaState;
+    private static boolean supportsCompute;
+    private static boolean supportsImageLoadStore;
+    private static boolean supportsSSBO;
+    private static boolean supportsBufferStorage;
+    private static boolean supportsClearTexture;
+    private static boolean supportsTesselation;
+    private static boolean supportsSamplerObjects;
+    private static int maxImageUnits;
+    private static int maxSSBOBindings;
+    private static int maxGlslVersion;
+    private static boolean supportsGpuShader4;
+    @Getter private static int glMajor;
+    @Getter private static int glMinor;
+    @Getter private static boolean coreProfile;
+
+    // Sampler object state tracking (null if unsupported)
+    private static int[] samplers;
+
+    private static final Pattern SEMVER_PATTERN = Pattern.compile("(?<major>\\d+)\\.(?<minor>\\d+)\\.*(?<bugfix>\\d*)(.*)");
+
+    private RenderSystem() {}
+
+    private static boolean rendererInitialized;
+
+    public static void initRenderer() {
+        if (rendererInitialized) return;
+        rendererInitialized = true;
+        try {
+            if (GLStateManager.vendorIsIntel() && GLStateManager.isWindows()) {
+                dsaState = new DSAUnsupported();
+                GLStateManager.LOGGER.info("Detected Intel drivers on Windows, disabling DSA.");
+            } else if (!GLStateManager.getInitConfig().isDSAEnabled()) {
+                dsaState = new DSAUnsupported();
+                GLStateManager.LOGGER.info("enableDSA is set to false, disabling DSA.");
+            } else if (GLStateManager.capabilities.OpenGL45) {
+                dsaState = (Runtime.version().feature() > 8 && GLStateManager.capabilities.GL_EXT_direct_state_access) ? new DSAEXT() : new DSACore();
+                GLStateManager.LOGGER.info("OpenGL 4.5 detected, enabling DSA.");
+            }
+
+        } catch (NoSuchFieldError ignored) {
+        }
+        try {
+            if (dsaState == null && GLStateManager.capabilities.GL_ARB_direct_state_access) {
+                dsaState = new DSAARB();
+                GLStateManager.LOGGER.info("ARB_direct_state_access detected, enabling DSA.");
+            }
+        } catch (NoSuchFieldError ignored) {
+        }
+        if (dsaState == null) {
+            dsaState = new DSAUnsupported();
+            GLStateManager.LOGGER.info("No DSA support detected, falling back to legacy OpenGL.");
+        }
+
+        BackendManager.init();
+
+        supportsCompute = supportsCompute();
+        supportsTesselation = GLStateManager.capabilities.GL_ARB_tessellation_shader || GLStateManager.capabilities.OpenGL40;
+
+        supportsImageLoadStore = GLStateManager.capabilities.OpenGL42
+                || GLStateManager.capabilities.GL_ARB_shader_image_load_store
+                || GLStateManager.capabilities.GL_EXT_shader_image_load_store;
+        supportsSSBO = GLStateManager.capabilities.OpenGL43 || GLStateManager.capabilities.GL_ARB_shader_storage_buffer_object;
+        supportsBufferStorage = GLStateManager.capabilities.OpenGL44 || GLStateManager.capabilities.GL_ARB_buffer_storage;
+        supportsClearTexture = GLStateManager.capabilities.OpenGL44 || GLStateManager.capabilities.GL_ARB_clear_texture;
+
+        // Cache maximum image units
+        if (supportsImageLoadStore) {
+            if (GLStateManager.capabilities.OpenGL42) {
+                maxImageUnits = RENDER_BACKEND.getInteger(GL42.GL_MAX_IMAGE_UNITS);
+            } else if (GLStateManager.capabilities.GL_ARB_shader_image_load_store) {
+                maxImageUnits = RENDER_BACKEND.getInteger(ARBShaderImageLoadStore.GL_MAX_IMAGE_UNITS);
+            } else {
+                maxImageUnits = RENDER_BACKEND.getInteger(EXTShaderImageLoadStore.GL_MAX_IMAGE_UNITS_EXT);
+            }
+        } else {
+            maxImageUnits = 0;
+        }
+
+        // Cache maximum SSBO bindings
+        if (supportsSSBO) {
+            if (GLStateManager.capabilities.OpenGL43) {
+                maxSSBOBindings = RENDER_BACKEND.getInteger(GL43.GL_MAX_SHADER_STORAGE_BUFFER_BINDINGS);
+            } else {
+                maxSSBOBindings = RENDER_BACKEND.getInteger(ARBShaderStorageBufferObject.GL_MAX_SHADER_STORAGE_BUFFER_BINDINGS);
+            }
+        } else {
+            maxSSBOBindings = 0;
+        }
+
+        // Check for sampler objects support (GL 3.3+ or ARB extension)
+        supportsSamplerObjects = GLStateManager.capabilities.OpenGL33 || GLStateManager.capabilities.GL_ARB_sampler_objects;
+        if (supportsSamplerObjects) {
+            samplers = new int[RENDER_BACKEND.getInteger(GL20.GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS)];
+        }
+
+        maxGlslVersion = Integer.parseInt(parseGlVersionString(RENDER_BACKEND.getString(GL20.GL_SHADING_LANGUAGE_VERSION)));
+        supportsGpuShader4 = GLStateManager.capabilities.GL_EXT_gpu_shader4;
+
+        GLStateManager.LOGGER.info("Max GLSL version: {}, GPU Shader4: {}", maxGlslVersion, supportsGpuShader4);
+        GLStateManager.LOGGER.info("Image Load/Store: {}, Max Image Units: {}", supportsImageLoadStore, maxImageUnits);
+        GLStateManager.LOGGER.info("SSBO: {}, Max SSBO Bindings: {}", supportsSSBO, maxSSBOBindings);
+        GLStateManager.LOGGER.info("Buffer Storage: {}, Clear Texture: {}, Sampler Objects: {}", supportsBufferStorage, supportsClearTexture, supportsSamplerObjects);
+
+        if (GLStateManager.capabilities.OpenGL32) {
+            final int profileMask = RENDER_BACKEND.getInteger(GL32.GL_CONTEXT_PROFILE_MASK);
+            if ((profileMask & GL32.GL_CONTEXT_CORE_PROFILE_BIT) != 0) {
+                coreProfile = true;
+                GLStateManager.LOGGER.info("GL 3.3 core profile detected, enabling FFP shader emulation.");
+                ShaderManager.getInstance().enable();
+            } else {
+                throw new IllegalStateException("Non-core GL context (profile mask 0x" + Integer.toHexString(profileMask)
+                    + "); FFP emulation requires a core profile and nothing would render. Context creation should have rejected this.");
+            }
+        }
+
+        final Matcher glVerMatcher = SEMVER_PATTERN.matcher(RENDER_BACKEND.getString(GL11.GL_VERSION));
+        if (glVerMatcher.matches()) {
+            glMajor = Integer.parseInt(glVerMatcher.group("major"));
+            glMinor = Integer.parseInt(glVerMatcher.group("minor"));
+        }
+    }
+
+    public static void generateMipmaps(int texture, int mipmapTarget) {
+        dsaState.generateMipmaps(texture, mipmapTarget);
+    }
+
+    public static void bindAttributeLocation(int program, int index, CharSequence name) {
+        RENDER_BACKEND.bindAttribLocation(program, index, name);
+    }
+
+    public static void texImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, @Nullable ByteBuffer pixels) {
+        GLStateManager.glBindTexture(target, texture);
+        GLStateManager.suspendPixelUnpackBuffer();
+        RENDER_BACKEND.texImage2D(target, level, internalformat, width, height, border, format, type, pixels);
+        GLStateManager.restorePixelUnpackBuffer();
+        if (target == GL11.GL_TEXTURE_2D && level == 0) {
+            TextureInfoCache.INSTANCE.onTexImage2D(target, level, internalformat, width, height, border, format, type, pixels);
+        }
+    }
+
+    public static void uniformMatrix4fv(int location, boolean transpose, FloatBuffer matrix) {
+        RENDER_BACKEND.uniformMatrix4(location, transpose, matrix);
+    }
+
+    public static void copyTexImage2D(int target, int level, int internalFormat, int x, int y, int width, int height, int border) {
+        GLStateManager.glCopyTexImage2D(target, level, internalFormat, x, y, width, height, border);
+    }
+
+    public static void uniform1f(int location, float v0) {
+        RENDER_BACKEND.uniform1f(location, v0);
+    }
+
+    public static void uniform1i(int location, int v0) {
+        RENDER_BACKEND.uniform1i(location, v0);
+    }
+
+    public static void uniform2f(int location, float v0, float v1) {
+        RENDER_BACKEND.uniform2f(location, v0, v1);
+    }
+
+    public static void uniform2i(int location, int v0, int v1) {
+        RENDER_BACKEND.uniform2i(location, v0, v1);
+    }
+
+    public static void uniform3f(int location, float v0, float v1, float v2) {
+        RENDER_BACKEND.uniform3f(location, v0, v1, v2);
+    }
+
+    public static void uniform3i(int location, int v0, int v1, int v2) {RENDER_BACKEND.uniform3i(location, v0, v1, v2);}
+
+    public static void uniform4f(int location, float v0, float v1, float v2, float v3) {
+        RENDER_BACKEND.uniform4f(location, v0, v1, v2, v3);
+    }
+
+    public static void uniform4i(int location, int v0, int v1, int v2, int v3) {
+        RENDER_BACKEND.uniform4i(location, v0, v1, v2, v3);
+    }
+
+    public static int getAttribLocation(int programId, String name) {
+        return RENDER_BACKEND.getAttribLocation(programId, name);
+    }
+
+    public static int getUniformLocation(int programId, String name) {
+        return RENDER_BACKEND.getUniformLocation(programId, name);
+    }
+
+    public static void texParameteriv(int texture, int target, int pname, IntBuffer params) {
+        dsaState.texParameteriv(texture, target, pname, params);
+    }
+
+    public static void copyTexSubImage2D(int destTexture, int target, int i, int i1, int i2, int i3, int i4, int width, int height) {
+        dsaState.copyTexSubImage2D(destTexture, target, i, i1, i2, i3, i4, width, height);
+    }
+
+    public static void texParameteri(int texture, int target, int pname, int param) {
+        dsaState.texParameteri(texture, target, pname, param);
+    }
+
+    public static void texParameterf(int texture, int target, int pname, float param) {
+        dsaState.texParameterf(texture, target, pname, param);
+    }
+
+    public static void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, ByteBuffer pixels) {
+        GLStateManager.suspendPixelUnpackBuffer();
+        dsaState.textureImage2D(texture, target, level, internalformat, width, height, border, format, type, pixels);
+        GLStateManager.restorePixelUnpackBuffer();
+    }
+
+    public static void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, IntBuffer pixels) {
+        GLStateManager.suspendPixelUnpackBuffer();
+        dsaState.textureImage2D(texture, target, level, internalformat, width, height, border, format, type, pixels);
+        GLStateManager.restorePixelUnpackBuffer();
+    }
+
+    public static void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, ByteBuffer pixels) {
+        GLStateManager.suspendPixelUnpackBuffer();
+        dsaState.textureSubImage2D(texture, target, level, xoffset, yoffset, width, height, format, type, pixels);
+        GLStateManager.restorePixelUnpackBuffer();
+    }
+
+    public static void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, IntBuffer pixels) {
+        GLStateManager.suspendPixelUnpackBuffer();
+        dsaState.textureSubImage2D(texture, target, level, xoffset, yoffset, width, height, format, type, pixels);
+        GLStateManager.restorePixelUnpackBuffer();
+    }
+
+    public static void texImage1D(int texture, int target, int level, int internalformat, int width, int border, int format, int type, ByteBuffer pixels) {
+        RENDER_BACKEND.bindTexture(target, texture);
+        GLStateManager.suspendPixelUnpackBuffer();
+        RENDER_BACKEND.texImage1D(target, level, internalformat, width, border, format, type, pixels);
+        GLStateManager.restorePixelUnpackBuffer();
+    }
+
+    public static void texImage3D(int texture, int target, int level, int internalformat, int width, int height, int depth, int border, int format, int type, ByteBuffer pixels) {
+        RENDER_BACKEND.bindTexture(target, texture);
+        GLStateManager.suspendPixelUnpackBuffer();
+        RENDER_BACKEND.texImage3D(target, level, internalformat, width, height, depth, border, format, type, pixels);
+        GLStateManager.restorePixelUnpackBuffer();
+    }
+
+    public static String getProgramInfoLog(int program) {
+        return RENDER_BACKEND.getProgramInfoLog(program, RENDER_BACKEND.getProgrami(program, GL20.GL_INFO_LOG_LENGTH));
+    }
+
+    public static String getShaderInfoLog(int shader) {
+        return RENDER_BACKEND.getShaderInfoLog(shader, RENDER_BACKEND.getShaderi(shader, GL20.GL_INFO_LOG_LENGTH));
+    }
+
+    public static void drawBuffers(int framebuffer, IntBuffer buffers) {
+        dsaState.drawBuffers(framebuffer, buffers);
+    }
+
+    public static void readBuffer(int framebuffer, int buffer) {
+        dsaState.readBuffer(framebuffer, buffer);
+    }
+
+    public static String getActiveUniform(int program, int index, int maxLength, IntBuffer sizeType) {
+        return RENDER_BACKEND.getActiveUniform(program, index, maxLength, sizeType);
+    }
+
+    public static void readPixels(int x, int y, int width, int height, int format, int type, FloatBuffer pixels) {
+        GLStateManager.suspendPixelPackBuffer();
+        RENDER_BACKEND.readPixels(x, y, width, height, format, type, pixels);
+        GLStateManager.restorePixelPackBuffer();
+    }
+
+    public static void bufferData(int target, FloatBuffer data, int usage) {
+        GLStateManager.glBufferData(target, data, usage);
+    }
+
+    public static int bufferStorage(int target, FloatBuffer data, int usage) {
+        return dsaState.bufferStorage(target, data, usage);
+    }
+
+    public static void vertexAttrib4f(int index, float v0, float v1, float v2, float v3) {
+        RENDER_BACKEND.vertexAttrib4f(index, v0, v1, v2, v3);
+    }
+
+    public static void detachShader(int program, int shader) {
+        RENDER_BACKEND.detachShader(program, shader);
+    }
+
+    public static void framebufferTexture2D(int fb, int fbtarget, int attachment, int target, int texture, int levels) {
+        dsaState.framebufferTexture2D(fb, fbtarget, attachment, target, texture, levels);
+    }
+
+    public static int getTexParameteri(int texture, int target, int pname) {
+        return dsaState.getTexParameteri(texture, target, pname);
+    }
+
+    public static int getTexLevelParameteri(int texture, int level, int pname) {
+        return dsaState.getTexLevelParameteri(texture, level, pname);
+    }
+
+    public static void bindImageTexture(int unit, int texture, int level, boolean layered, int layer, int access, int format) {
+        RENDER_BACKEND.bindImageTexture(unit, texture, level, layered, layer, access, format);
+    }
+
+    public static int getMaxImageUnits() {
+        return maxImageUnits;
+    }
+
+    public static boolean supportsImageLoadStore() {
+        return supportsImageLoadStore;
+    }
+
+    public static boolean supportsSSBO() {
+        return supportsSSBO;
+    }
+
+    public static boolean supportsBufferStorage() {
+        return supportsBufferStorage;
+    }
+
+    public static boolean supportsClearTexture() {
+        return supportsClearTexture;
+    }
+
+    public static int getMaxSSBOBindings() {
+        return maxSSBOBindings;
+    }
+
+    public static void getProgramiv(int program, int value, IntBuffer storage) {
+        RENDER_BACKEND.getProgramiv(program, value, storage);
+    }
+
+    public static void dispatchCompute(int workX, int workY, int workZ) {
+        RENDER_BACKEND.dispatchCompute(workX, workY, workZ);
+    }
+
+    public static void dispatchCompute(Vector3i workGroups) {
+        RENDER_BACKEND.dispatchCompute(workGroups.x, workGroups.y, workGroups.z);
+    }
+
+    public static void dispatchComputeIndirect(long offset) {
+        RENDER_BACKEND.dispatchComputeIndirect(offset);
+    }
+
+    public static void bindBuffer(int target, int buffer) {
+        GLStateManager.glBindBuffer(target, buffer);
+    }
+
+    public static void memoryBarrier(int barriers) {
+        if (supportsCompute) {
+            RENDER_BACKEND.memoryBarrier(barriers);
+        }
+    }
+
+    public static boolean supportsBufferBlending() {
+        return GLStateManager.capabilities.GL_ARB_draw_buffers_blend || GLStateManager.capabilities.OpenGL40;
+    }
+
+    public static void disableBufferBlend(int buffer) {
+        RENDER_BACKEND.disablei(GL11.GL_BLEND, buffer);
+        GLStateManager.getBlendMode().setUnknownState();
+    }
+
+    public static void enableBufferBlend(int buffer) {
+        RENDER_BACKEND.enablei(GL11.GL_BLEND, buffer);
+        GLStateManager.getBlendMode().setUnknownState();
+    }
+
+    public static void blendFuncSeparatei(int buffer, int srcRGB, int dstRGB, int srcAlpha, int dstAlpha) {
+        RENDER_BACKEND.blendFuncSeparatei(buffer, srcRGB, dstRGB, srcAlpha, dstAlpha);
+    }
+
+    public static void bindTextureToUnit(int unit, int texture) {
+        dsaState.bindTextureToUnit(unit, texture);
+    }
+
+    public static void bindTextureToUnit(int target, int unit, int texture) {
+        dsaState.bindTextureToUnit(target, unit, texture);
+    }
+
+    public static final FloatBuffer PROJECTION_MATRIX_BUFFER = BufferUtils.createFloatBuffer(16);
+
+    public static void setupProjectionMatrix(Matrix4f matrix) {
+        GLStateManager.glMatrixMode(GL11.GL_PROJECTION);
+        GLStateManager.glPushMatrix();
+        matrix.get(0, PROJECTION_MATRIX_BUFFER);
+        GLStateManager.glLoadMatrix(PROJECTION_MATRIX_BUFFER);
+        GLStateManager.glMatrixMode(GL11.GL_MODELVIEW);
+    }
+
+    public static void restoreProjectionMatrix() {
+        GLStateManager.glMatrixMode(GL11.GL_PROJECTION);
+        GLStateManager.glPopMatrix();
+        GLStateManager.glMatrixMode(GL11.GL_MODELVIEW);
+    }
+
+    public static void blitFramebuffer(int source, int dest, int offsetX, int offsetY, int width, int height, int offsetX2, int offsetY2, int width2,
+            int height2, int bufferChoice, int filter) {
+        dsaState.blitFramebuffer(source, dest, offsetX, offsetY, width, height, offsetX2, offsetY2, width2, height2, bufferChoice, filter);
+    }
+
+    public static int createFramebuffer() {
+        return dsaState.createFramebuffer();
+    }
+
+    public static int createTexture(int target) {
+        return dsaState.createTexture(target);
+    }
+
+    // TODO: Proper notification of compute support
+    public static boolean supportsCompute() {
+        try {
+            return GLStateManager.capabilities.GL_ARB_compute_shader;
+        } catch (Exception ignored) {
+            return false;
+        }
+    }
+
+    public static int createBuffers() {
+        return GLStateManager.glGenBuffers();
+    }
+
+    public static void bindBufferBase(int target, int index, int buffer) {
+        RENDER_BACKEND.bindBufferBase(target, index, buffer);
+    }
+
+    public static void bufferStorage(int target, long size, int flags) {
+        GLStateManager.glBufferStorage(target, size, flags);
+    }
+
+    public static void clearBufferSubData(int target, int internalFormat, long offset, long size, int format, int type, int[] data) {
+        final ByteBuffer buf = BufferUtils.createByteBuffer(data.length * 4);
+        buf.asIntBuffer().put(data);
+        GLStateManager.glClearBufferSubData(target, internalFormat, offset, size, format, type, buf);
+    }
+
+    public static void deleteBuffers(int buffer) {
+        GLStateManager.glDeleteBuffers(buffer);
+    }
+
+    public static long getVRAM() {
+        if (GLStateManager.capabilities.GL_NVX_gpu_memory_info) {
+            return RENDER_BACKEND.getInteger(NVXGpuMemoryInfo.GL_GPU_MEMORY_INFO_CURRENT_AVAILABLE_VIDMEM_NVX) * 1024L;
+        } else {
+            // Default to 4GB if we can't query VRAM
+            return 4294967296L;
+        }
+    }
+
+    public static void clearTexImage(int texture, int target, int level, int format, int type) {
+        RENDER_BACKEND.clearTexImage(texture, level, format, type);
+    }
+
+    public static void textureStorage1D(int texture, int target, int levels, int internalFormat, int width) {
+        dsaState.textureStorage1D(texture, target, levels, internalFormat, width);
+    }
+
+    public static void textureStorage2D(int texture, int target, int levels, int internalFormat, int width, int height) {
+        dsaState.textureStorage2D(texture, target, levels, internalFormat, width, height);
+    }
+
+    public static void textureStorage3D(int texture, int target, int levels, int internalFormat, int width, int height, int depth) {
+        dsaState.textureStorage3D(texture, target, levels, internalFormat, width, height, depth);
+    }
+
+    public static int getMaxGlslVersion() {
+        return maxGlslVersion;
+    }
+
+    public static boolean supportsGpuShader4() {
+        return supportsGpuShader4;
+    }
+
+    public static boolean supportsSnormFormats() {
+        return GLStateManager.capabilities.OpenGL31;
+    }
+
+    public static boolean supportsPackedFloatRenderable() {
+        return GLStateManager.capabilities.OpenGL30 && maxGlslVersion >= 130;
+    }
+
+    public static boolean supportsTesselation() {
+        return supportsTesselation;
+    }
+
+    public static boolean supportsSamplerObjects() {
+        return supportsSamplerObjects;
+    }
+
+    public static int genSampler() {
+        if (!supportsSamplerObjects) return 0;
+        return RENDER_BACKEND.genSamplers();
+    }
+
+    public static void destroySampler(int sampler) {
+        if (!supportsSamplerObjects || sampler == 0) return;
+        GLStateManager.glDeleteSamplers(sampler);
+    }
+
+    public static void samplerParameteri(int sampler, int pname, int param) {
+        if (!supportsSamplerObjects || sampler == 0) return;
+        RENDER_BACKEND.samplerParameteri(sampler, pname, param);
+    }
+
+    public static void bindSamplerToUnit(int unit, int sampler) {
+        if (!supportsSamplerObjects) return;
+        if (samplers[unit] == sampler) return;
+        RENDER_BACKEND.bindSampler(unit, sampler);
+        samplers[unit] = sampler;
+    }
+
+    public static void unbindAllSamplers() {
+        if (!supportsSamplerObjects) return;
+        for (int i = 0; i < samplers.length; i++) {
+            if (samplers[i] != 0) {
+                RENDER_BACKEND.bindSampler(i, 0);
+                samplers[i] = 0;
+            }
+        }
+    }
+
+    /** Parse a GL version string (e.g. "4.6.0 NVIDIA ...") into concatenated digits "460" */
+    static String parseGlVersionString(String info) {
+        final Matcher matcher = SEMVER_PATTERN.matcher(Objects.requireNonNull(info));
+        if (!matcher.matches()) {
+            throw new IllegalStateException("Could not parse GL version from \"" + info + "\"");
+        }
+        final String major = matcher.group("major");
+        final String minor = matcher.group("minor");
+        String bugfix = matcher.group("bugfix");
+        if (bugfix == null || bugfix.isEmpty()) bugfix = "0";
+        return major + minor + bugfix;
+    }
+
+    /** Parse a GL version string into packed major*10+minor (e.g. "4.3.0 - Build ..." -> 43), or -1 if unparseable. */
+    public static int parseMajorMinor(String glVersion) {
+        if (glVersion == null) return -1;
+        final Matcher matcher = SEMVER_PATTERN.matcher(glVersion.trim());
+        if (!matcher.matches()) return -1;
+        return Integer.parseInt(matcher.group("major")) * 10 + Integer.parseInt(matcher.group("minor"));
+    }
+
+    public static boolean isContextValid(int requestedMajor, int requestedMinor, int actualVersion, boolean coreBitSet) {
+        if (!coreBitSet) return false;
+        if (actualVersion < 0) return true;
+        return actualVersion >= requestedMajor * 10 + requestedMinor;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/Vendor.java

@@ -0,0 +1,27 @@
+package com.gtnewhorizons.angelica.glsm;
+
+/// Matches
+public enum Vendor {
+    AMD("amd"),
+    INTEL("intel"),
+    MESA("mesa"),
+    NVIDIA("nvidia"),
+    UNKNOWN("");
+
+    final String[] names;
+
+    Vendor(String... names) {
+        this.names = names;
+    }
+
+    public static Vendor getVendor(String vendorString) {
+        for (var v : values()) {
+            for (var name : v.names) {
+                if (vendorString.contains(name)) return v;
+            }
+        }
+
+        // Shouldn't be needed as "" matches everything, but sanity checks good.
+        return UNKNOWN;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/backend/BackendManager.java

@@ -0,0 +1,54 @@
+package com.gtnewhorizons.angelica.glsm.backend;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.Iterator;
+import java.util.ServiceConfigurationError;
+import java.util.ServiceLoader;
+
+public final class BackendManager {
+    private static final Logger LOGGER = LogManager.getLogger("BackendManager");
+
+    public static final RenderBackend RENDER_BACKEND = loadService();
+
+    private BackendManager() {}
+
+    public static void init() {
+        RENDER_BACKEND.init();
+        LOGGER.info("Initialized backend: {} (priority {})", RENDER_BACKEND.getName(), RENDER_BACKEND.getPriority());
+    }
+
+    public static void shutdown() {
+        RENDER_BACKEND.shutdown();
+    }
+
+    private static RenderBackend loadService() {
+        final ServiceLoader<RenderBackend> loader = ServiceLoader.load(RenderBackend.class, RenderBackend.class.getClassLoader());
+
+        RenderBackend best = null;
+        final Iterator<RenderBackend> iterator = loader.iterator();
+        int attempts = 0;
+
+        while (attempts < 16) {
+            try {
+                attempts++;
+                if (!iterator.hasNext()) break;
+                final RenderBackend backend = iterator.next();
+                LOGGER.info("Found backend: {} (priority {})", backend.getName(), backend.getPriority());
+                if (backend.isAvailable() && (best == null || backend.getPriority() > best.getPriority())) {
+                    best = backend;
+                }
+            } catch (ServiceConfigurationError | LinkageError e) {
+                LOGGER.debug("Skipping unavailable backend: {}", e.getMessage());
+            }
+        }
+
+        if (best == null) {
+            throw new IllegalStateException("No available render backend!");
+        }
+
+        LOGGER.info("Selected backend: {} (priority {})", best.getName(), best.getPriority());
+        return best;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/backend/DebugMessageHandler.java

@@ -0,0 +1,6 @@
+package com.gtnewhorizons.angelica.glsm.backend;
+
+@FunctionalInterface
+public interface DebugMessageHandler {
+    void handleMessage(int source, int type, int id, int severity, String message);
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/backend/RenderBackend.java

@@ -0,0 +1,345 @@
+package com.gtnewhorizons.angelica.glsm.backend;
+
+import com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities;
+import org.lwjgl.opengl.GL20;
+
+import java.nio.ByteBuffer;
+import java.nio.DoubleBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+import java.nio.ShortBuffer;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Abstract rendering backend.
+ */
+public abstract class RenderBackend {
+
+    public abstract void init();
+    public abstract void shutdown();
+    public abstract boolean isAvailable();
+    public abstract String getName();
+
+    /** Returns true if the current thread has a valid render context. Safe to call from any thread. */
+    public abstract boolean hasContext();
+
+    /** Higher priority backends are preferred. */
+    public int getPriority() { return 0; }
+
+    public boolean supportsFileDrop() { return false; }
+
+    public void startFileDrop() {}
+
+    public void stopFileDrop() {}
+
+    public List<String> pollDroppedFiles() { return Collections.emptyList(); }
+
+    public abstract int getMinGLSLVersion();
+
+    public abstract void flush();
+    public abstract void finish();
+
+    public void onFrameBegin() {}
+    public void onFrameEnd() {}
+
+    public abstract void enable(int cap);
+    public abstract void enablei(int cap, int index);
+    public abstract void disable(int cap);
+    public abstract void disablei(int cap, int index);
+    public abstract void blendFuncSeparatei(int buf, int srcRGB, int dstRGB, int srcAlpha, int dstAlpha);
+    public abstract void blendFunc(int sfactor, int dfactor);
+    public abstract void blendFuncSeparate(int srcRGB, int dstRGB, int srcAlpha, int dstAlpha);
+    public abstract void blendEquation(int mode);
+    public abstract void blendEquationSeparate(int modeRGB, int modeAlpha);
+    public abstract void blendColor(float red, float green, float blue, float alpha);
+    public abstract void depthFunc(int func);
+    public abstract void depthMask(boolean flag);
+    public abstract void colorMask(boolean red, boolean green, boolean blue, boolean alpha);
+    public abstract void cullFace(int mode);
+    public abstract void frontFace(int mode);
+    public abstract void polygonMode(int face, int mode);
+    public abstract void polygonOffset(float factor, float units);
+    public abstract void stencilFunc(int func, int ref, int mask);
+    public abstract void stencilOp(int sfail, int dpfail, int dppass);
+    public abstract void stencilMask(int mask);
+    public abstract void stencilFuncSeparate(int face, int func, int ref, int mask);
+    public abstract void stencilOpSeparate(int face, int sfail, int dpfail, int dppass);
+    public abstract void stencilMaskSeparate(int face, int mask);
+    public abstract void viewport(int x, int y, int width, int height);
+    public abstract void depthRange(double nearVal, double farVal);
+    public abstract void scissor(int x, int y, int width, int height);
+    public abstract void clearColor(float red, float green, float blue, float alpha);
+    public abstract void clearDepth(double depth);
+    public abstract void clearStencil(int s);
+    public abstract void clear(int mask);
+    public abstract void lineWidth(float width);
+    public abstract void pointSize(float size);
+    public abstract void logicOp(int opcode);
+    public abstract void hint(int target, int mode);
+
+    public abstract void drawArrays(int mode, int first, int count);
+    public abstract void drawElements(int mode, int count, int type, long indices);
+    public void drawElements(int mode, ByteBuffer indices) {}
+    public void drawElements(int mode, IntBuffer indices) {}
+    public void drawElements(int mode, ShortBuffer indices) {}
+    public void drawElements(int mode, int count, int type, ByteBuffer indices) {}
+    public abstract void multiDrawElementsIndirect(int mode, int type, long indirect, int drawcount, int stride);
+    public abstract void copyBufferSubData(int readTarget, int writeTarget, long readOffset, long writeOffset, long size);
+    public abstract void drawElementsInstanced(int mode, int count, int type, long indices, int primcount);
+    public abstract void drawArraysInstanced(int mode, int first, int count, int primcount);
+    public void provokingVertex(int provokeMode) {}
+    public abstract void drawElementsBaseVertex(int mode, int count, int type, long indices, int baseVertex);
+    public abstract void multiDrawElementsBaseVertex(int mode, long pCount, int type, long pIndices, int drawcount, long pBaseVertex);
+    public abstract void drawBuffer(int mode);
+    public abstract void dispatchCompute(int numGroupsX, int numGroupsY, int numGroupsZ);
+    public abstract void dispatchComputeIndirect(long offset);
+
+    public abstract int genTextures();
+    public abstract void genTextures(IntBuffer textures);
+    public abstract void deleteTextures(int texture);
+    public abstract void bindTexture(int target, int texture);
+    public abstract void activeTexture(int texture);
+    public abstract void texImage2D(int target, int level, int internalFormat, int width, int height, int border, int format, int type, ByteBuffer pixels);
+    public abstract void texImage2D(int target, int level, int internalFormat, int width, int height, int border, int format, int type, DoubleBuffer pixels);
+    public abstract void texImage2D(int target, int level, int internalFormat, int width, int height, int border, int format, int type, FloatBuffer pixels);
+    public abstract void texImage2D(int target, int level, int internalFormat, int width, int height, int border, int format, int type, IntBuffer pixels);
+    public abstract void texImage2D(int target, int level, int internalFormat, int width, int height, int border, int format, int type, long pixelBufferOffset);
+    public abstract void texSubImage2D(int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, ByteBuffer pixels);
+    public abstract void texSubImage2D(int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, IntBuffer pixels);
+    public abstract void copyTexSubImage2D(int target, int level, int xoffset, int yoffset, int x, int y, int width, int height);
+    public void texImage1D(int target, int level, int internalFormat, int width, int border, int format, int type, ByteBuffer pixels) {}
+    public void texImage3D(int target, int level, int internalFormat, int width, int height, int depth, int border, int format, int type, ByteBuffer pixels) {}
+    public void texImage3D(int target, int level, int internalFormat, int width, int height, int depth, int border, int format, int type, IntBuffer pixels) {}
+    public void texSubImage1D(int target, int level, int xoffset, int width, int format, int type, ByteBuffer pixels) {}
+    public void texSubImage2D(int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, long pboOffset) {}
+    public void texSubImage3D(int target, int level, int xoffset, int yoffset, int zoffset, int width, int height, int depth, int format, int type, ByteBuffer pixels) {}
+    public void copyTexImage1D(int target, int level, int internalFormat, int x, int y, int width, int border) {}
+    public void copyTexImage2D(int target, int level, int internalFormat, int x, int y, int width, int height, int border) {}
+    public void copyTexSubImage1D(int target, int level, int xoffset, int x, int y, int width) {}
+    public void copyTexSubImage3D(int target, int level, int xoffset, int yoffset, int zoffset, int x, int y, int width, int height) {}
+    public abstract void texParameteri(int target, int pname, int param);
+    public abstract void texParameterf(int target, int pname, float param);
+    public abstract void texParameteriv(int target, int pname, IntBuffer params);
+    public abstract void texParameterfv(int target, int pname, FloatBuffer params);
+    public abstract int getTexParameteri(int target, int pname);
+    public abstract float getTexParameterf(int target, int pname);
+    public abstract int getTexLevelParameteri(int target, int level, int pname);
+    public abstract void generateMipmap(int target);
+    public abstract void pixelStorei(int pname, int param);
+    public void sampleCoverage(float value, boolean invert) {}
+
+
+    public abstract int genSamplers();
+    public abstract void deleteSamplers(int sampler);
+    public abstract void bindSampler(int unit, int sampler);
+    public abstract void samplerParameteri(int sampler, int pname, int param);
+    public abstract void samplerParameterf(int sampler, int pname, float param);
+
+    public abstract int genFramebuffers();
+    public abstract void deleteFramebuffers(int framebuffer);
+    public abstract void bindFramebuffer(int target, int framebuffer);
+    public abstract void framebufferTexture2D(int target, int attachment, int textarget, int texture, int level);
+    public abstract void framebufferTexture(int target, int attachment, int texture, int level);
+    public abstract int checkFramebufferStatus(int target);
+    public abstract void blitFramebuffer(int srcX0, int srcY0, int srcX1, int srcY1, int dstX0, int dstY0, int dstX1, int dstY1, int mask, int filter);
+    public abstract void drawBuffers(int buffer);
+    public abstract void drawBuffers(IntBuffer bufs);
+    public abstract void readBuffer(int mode);
+    public abstract void readPixels(int x, int y, int width, int height, int format, int type, ByteBuffer pixels);
+    public abstract void readPixels(int x, int y, int width, int height, int format, int type, FloatBuffer pixels);
+    public abstract void readPixels(int x, int y, int width, int height, int format, int type, IntBuffer pixels);
+    public abstract void getTexImage(int target, int level, int format, int type, ByteBuffer pixels);
+    public abstract void getTexImage(int target, int level, int format, int type, IntBuffer pixels);
+    public abstract void getTexImage(int target, int level, int format, int type, long pixelBufferOffset);
+    public abstract int getFramebufferAttachmentParameteri(int target, int attachment, int pname);
+
+    public abstract int createShader(int type);
+    public abstract void deleteShader(int shader);
+    public abstract void shaderSource(int shader, CharSequence source);
+    public abstract void compileShader(int shader);
+    public abstract int createProgram();
+    public abstract void deleteProgram(int program);
+    public abstract void attachShader(int program, int shader);
+    public abstract void detachShader(int program, int shader);
+    public abstract void linkProgram(int program);
+    public abstract void useProgram(int program);
+    public abstract String getShaderInfoLog(int shader, int maxLength);
+    public String getShaderInfoLog(int shader) {
+        return getShaderInfoLog(shader, getShaderi(shader, GL20.GL_INFO_LOG_LENGTH));
+    }
+    public abstract void getShaderInfoLog(int shader, IntBuffer length, ByteBuffer infoLog);
+    public abstract String getProgramInfoLog(int program, int maxLength);
+    public String getProgramInfoLog(int program) {
+        return getProgramInfoLog(program, getProgrami(program, GL20.GL_INFO_LOG_LENGTH));
+    }
+    public abstract void getProgramInfoLog(int program, IntBuffer length, ByteBuffer infoLog);
+    public abstract int getShaderi(int shader, int pname);
+    public abstract int getProgrami(int program, int pname);
+    public abstract void getProgramiv(int program, int pname, IntBuffer params);
+    public abstract String getActiveUniform(int program, int index, int maxLength, IntBuffer sizeType);
+    public abstract void getActiveUniform(int program, int index, IntBuffer length, IntBuffer size, IntBuffer type, ByteBuffer name);
+    public abstract void bindAttribLocation(int program, int index, CharSequence name);
+    public abstract int getAttribLocation(int program, CharSequence name);
+    public abstract int getAttribLocation(int program, ByteBuffer name);
+    public abstract int getUniformLocation(int program, CharSequence name);
+    public abstract int getUniformLocation(int program, ByteBuffer name);
+    public boolean isShader(int obj) { return false; }
+    public boolean isProgram(int obj) { return false; }
+    public void validateProgram(int program) {}
+    public void getAttachedShaders(int program, IntBuffer count, IntBuffer shaders) {
+        if (count != null) count.put(0, 0);
+    }
+    public String getShaderSource(int shader, int maxLength) { return ""; }
+    public abstract void getShaderSource(int shader, IntBuffer length, ByteBuffer source);
+
+    public abstract void uniform1i(int location, int v0);
+    public abstract void uniform1f(int location, float v0);
+    public void uniform1fv(int location, FloatBuffer values) {}
+    public abstract void uniform2f(int location, float v0, float v1);
+    public abstract void uniform2i(int location, int v0, int v1);
+    public abstract void uniform3f(int location, float v0, float v1, float v2);
+    public abstract void uniform3i(int location, int v0, int v1, int v2);
+    public abstract void uniform4f(int location, float v0, float v1, float v2, float v3);
+    public abstract void uniform4i(int location, int v0, int v1, int v2, int v3);
+    public abstract void uniform2(int location, FloatBuffer value);
+    public abstract void uniform3(int location, FloatBuffer value);
+    public abstract void uniform4(int location, FloatBuffer value);
+    public abstract void uniform1iv(int location, IntBuffer value);
+    public abstract void uniform2iv(int location, IntBuffer value);
+    public abstract void uniform3iv(int location, IntBuffer value);
+    public abstract void uniform4iv(int location, IntBuffer value);
+    public abstract void uniformMatrix3(int location, boolean transpose, FloatBuffer value);
+    public abstract void uniformMatrix4(int location, boolean transpose, FloatBuffer value);
+    public void uniformMatrix2(int location, boolean transpose, FloatBuffer matrices) {}
+    public void getUniformfv(int program, int location, FloatBuffer params) {}
+    public void getUniformiv(int program, int location, IntBuffer params) {}
+
+    public abstract void vertexAttrib2f(int index, float v0, float v1);
+    public abstract void vertexAttrib3f(int index, float v0, float v1, float v2);
+    public abstract void vertexAttrib4f(int index, float v0, float v1, float v2, float v3);
+
+    public abstract int genBuffers();
+    public abstract void deleteBuffers(int buffer);
+    public abstract void deleteBuffers(IntBuffer buffers);
+    public abstract void bindBuffer(int target, int buffer);
+    public abstract void bindBufferBase(int target, int index, int buffer);
+    public abstract void bufferData(int target, long size, int usage);
+    public abstract void bufferData(int target, ByteBuffer data, int usage);
+    public abstract void bufferData(int target, FloatBuffer data, int usage);
+    public abstract void bufferData(int target, ShortBuffer data, int usage);
+    public abstract void bufferData(int target, IntBuffer data, int usage);
+    public abstract void bufferData(int target, DoubleBuffer data, int usage);
+    public abstract void bufferData(int target, int[] data, int usage);
+    public abstract void bufferData(int target, float[] data, int usage);
+    public abstract void bufferSubData(int target, long offset, ByteBuffer data);
+    public abstract void bufferSubData(int target, long offset, ShortBuffer data);
+    public abstract void bufferSubData(int target, long offset, IntBuffer data);
+    public abstract void bufferSubData(int target, long offset, FloatBuffer data);
+    public abstract void bufferSubData(int target, long offset, DoubleBuffer data);
+    public abstract ByteBuffer mapBuffer(int target, int access);
+    public abstract ByteBuffer mapBuffer(int target, int access, long length, ByteBuffer old_buffer);
+    public abstract boolean unmapBuffer(int target);
+    public abstract void bufferStorage(int target, ByteBuffer data, int flags);
+    public abstract void bufferStorage(int target, long size, int flags);
+    public abstract void getBufferSubData(int target, long offset, ByteBuffer data);
+    public abstract void getBufferSubData(int target, long offset, ShortBuffer data);
+    public abstract void getBufferSubData(int target, long offset, IntBuffer data);
+    public abstract void getBufferSubData(int target, long offset, FloatBuffer data);
+    public abstract void getBufferSubData(int target, long offset, DoubleBuffer data);
+    public abstract int getBufferParameteri(int target, int pname);
+    public abstract boolean isBuffer(int buffer);
+    public abstract ByteBuffer mapBufferRange(int target, long offset, long length, int access);
+    public abstract void flushMappedBufferRange(int target, long offset, long length);
+
+    public abstract int genVertexArrays();
+    public abstract void deleteVertexArrays(int array);
+    public abstract void bindVertexArray(int array);
+    public abstract boolean isVertexArray(int array);
+    public abstract void vertexAttribPointer(int index, int size, int type, boolean normalized, int stride, long pointer);
+    public void vertexAttribPointer(int index, int size, int type, boolean normalized, int stride, ByteBuffer pointer) {
+        vertexAttribPointer(index, size, type, normalized, stride, MemoryUtilities.memAddress0(pointer));
+    }
+    public void vertexAttribIPointer(int index, int size, int type, int stride, ByteBuffer pointer) {
+        vertexAttribIPointer(index, size, type, stride, MemoryUtilities.memAddress0(pointer));
+    }
+    public abstract void vertexAttribIPointer(int index, int size, int type, int stride, long pointer);
+    public abstract void enableVertexAttribArray(int index);
+    public abstract void disableVertexAttribArray(int index);
+    public abstract void vertexAttribDivisor(int index, int divisor);
+    public abstract void bindVertexBuffer(int bindingindex, int buffer, long offset, int stride);
+    public abstract void vertexAttribFormat(int attribindex, int size, int type, boolean normalized, int relativeoffset);
+    public abstract void vertexAttribIFormat(int attribindex, int size, int type, int relativeoffset);
+    public abstract void vertexAttribBinding(int attribindex, int bindingindex);
+
+    public abstract int createTextures(int target);
+    public abstract void bindTextureUnit(int unit, int texture);
+    public abstract void textureParameteri(int texture, int target, int pname, int param);
+    public abstract void textureParameterf(int texture, int target, int pname, float param);
+    public abstract void textureParameteriv(int texture, int target, int pname, IntBuffer params);
+    public abstract void texStorage1D(int target, int levels, int internalFormat, int width);
+    public abstract void texStorage2D(int target, int levels, int internalFormat, int width, int height);
+    public abstract void texStorage3D(int target, int levels, int internalFormat, int width, int height, int depth);
+    public abstract void textureStorage1D(int texture, int levels, int internalFormat, int width);
+    public abstract void textureStorage2D(int texture, int levels, int internalFormat, int width, int height);
+    public abstract void textureStorage3D(int texture, int levels, int internalFormat, int width, int height, int depth);
+    public abstract void generateTextureMipmap(int texture);
+    public abstract void textureImage2DEXT(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, ByteBuffer pixels);
+    public abstract void textureImage2DEXT(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, IntBuffer pixels);
+    public abstract void textureSubImage2D(int texture, int level, int xoffset, int yoffset, int width, int height, int format, int type, ByteBuffer pixels);
+    public abstract void textureSubImage2D(int texture, int level, int xoffset, int yoffset, int width, int height, int format, int type, IntBuffer pixels);
+    public abstract int createFramebuffers();
+    public abstract void namedFramebufferTexture(int framebuffer, int attachment, int texture, int level);
+    public abstract void namedFramebufferReadBuffer(int framebuffer, int mode);
+    public abstract void namedFramebufferDrawBuffers(int framebuffer, IntBuffer bufs);
+    public abstract void blitNamedFramebuffer(int readFramebuffer, int drawFramebuffer, int srcX0, int srcY0, int srcX1, int srcY1, int dstX0, int dstY0, int dstX1, int dstY1, int mask, int filter);
+    public abstract int createBuffers();
+    public abstract void namedBufferData(int buffer, long size, int usage);
+    public abstract void namedBufferData(int buffer, ByteBuffer data, int usage);
+    public abstract void namedBufferData(int buffer, FloatBuffer data, int usage);
+    public abstract void namedBufferSubData(int buffer, long offset, ByteBuffer data);
+    public abstract void copyTextureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int x, int y, int width, int height);
+    public abstract int getTextureParameteri(int texture, int target, int pname);
+    public abstract int getTextureLevelParameteri(int texture, int level, int pname);
+
+    public abstract int getInteger(int pname);
+    public abstract void getInteger(int pname, IntBuffer params);
+    public abstract float getFloat(int pname);
+    public abstract void getFloat(int pname, FloatBuffer params);
+    public abstract boolean getBoolean(int pname);
+    public abstract void getBoolean(int pname, ByteBuffer params);
+    public abstract String getString(int pname);
+    public abstract String getStringi(int name, int index);
+    public abstract int getError();
+
+    public abstract long fenceSync(int condition, int flags);
+    public abstract int clientWaitSync(long sync, int flags, long timeout);
+    public abstract void deleteSync(long sync);
+
+    public abstract void clearBufferSubData(int target, int internalFormat, long offset, long size, int format, int type, ByteBuffer data);
+    public abstract void clearTexImage(int texture, int level, int format, int type);
+
+    public abstract void bindImageTexture(int unit, int texture, int level, boolean layered, int layer, int access, int format);
+    public abstract void memoryBarrier(int barriers);
+
+    public abstract void copyImageSubData(int srcName, int srcTarget, int srcLevel, int srcX, int srcY, int srcZ,
+                                           int dstName, int dstTarget, int dstLevel, int dstX, int dstY, int dstZ,
+                                           int srcWidth, int srcHeight, int srcDepth);
+
+    // Debug output
+    public boolean supportsDebugOutput() { return false; }
+    public int setupDebugOutput(DebugMessageHandler handler) { return 0; }
+    public int disableDebugOutput() { return 0; }
+
+    // Object labeling
+    public void objectLabel(int identifier, int name, CharSequence label) {}
+    public String getObjectLabel(int identifier, int name) { return ""; }
+
+    // Debug groups
+    public void pushDebugGroup(int source, int id, CharSequence message) {}
+    public void popDebugGroup() {}
+
+    // Debug message insertion
+    public void debugMessageInsert(int source, int type, int id, int severity, CharSequence message) {}
+
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/compat/FogHelper.java

@@ -0,0 +1,11 @@
+package com.gtnewhorizons.angelica.glsm.compat;
+
+/**
+ * Simple holder for fog color values captured from vanilla rendering.
+ * Used by terrain renderers to access fog state.
+ */
+public class FogHelper {
+    public static float red;
+    public static float green;
+    public static float blue;
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/compat/lwjgl/AngelicaCylinder.java

@@ -0,0 +1,142 @@
+package com.gtnewhorizons.angelica.glsm.compat.lwjgl;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.lwjgl.util.glu.Cylinder;
+
+import static org.lwjgl.opengl.GL11.GL_LINES;
+import static org.lwjgl.opengl.GL11.GL_LINE_LOOP;
+import static org.lwjgl.opengl.GL11.GL_POINTS;
+import static org.lwjgl.opengl.GL11.GL_TRIANGLE_STRIP;
+import static org.lwjgl.util.glu.GLU.GLU_FILL;
+import static org.lwjgl.util.glu.GLU.GLU_INSIDE;
+import static org.lwjgl.util.glu.GLU.GLU_LINE;
+import static org.lwjgl.util.glu.GLU.GLU_POINT;
+import static org.lwjgl.util.glu.GLU.GLU_SILHOUETTE;
+
+/**
+ * Core-profile compatible replacement for {@link Cylinder}.
+ */
+@SuppressWarnings("unused")
+public class AngelicaCylinder extends Cylinder {
+
+    private static final float PI = (float) Math.PI;
+
+    private void emitNormal(float x, float y, float z) {
+        final float mag = (float) Math.sqrt(x * x + y * y + z * z);
+        if (mag > 0.00001F) {
+            x /= mag;
+            y /= mag;
+            z /= mag;
+        }
+        GLStateManager.glNormal3f(x, y, z);
+    }
+
+    private void emitTexCoord(float x, float y) {
+        if (super.textureFlag) GLStateManager.glTexCoord2f(x, y);
+    }
+
+    @Override
+    public void draw(float baseRadius, float topRadius, float height, int slices, int stacks) {
+        final float da, dr, dz, nz, nsign;
+        float r, x, y, z;
+
+        nsign = (super.orientation == GLU_INSIDE) ? -1.0f : 1.0f;
+
+        da = 2.0f * PI / slices;
+        dr = (topRadius - baseRadius) / stacks;
+        dz = height / stacks;
+        nz = (baseRadius - topRadius) / height;
+
+        if (super.drawStyle == GLU_POINT) {
+            GLStateManager.glBegin(GL_POINTS);
+            for (int i = 0; i < slices; i++) {
+                x = cos(i * da);
+                y = sin(i * da);
+                emitNormal(x * nsign, y * nsign, nz * nsign);
+
+                z = 0.0f;
+                r = baseRadius;
+                for (int j = 0; j <= stacks; j++) {
+                    GLStateManager.glVertex3f(x * r, y * r, z);
+                    z += dz;
+                    r += dr;
+                }
+            }
+            GLStateManager.glEnd();
+        } else if (super.drawStyle == GLU_LINE || super.drawStyle == GLU_SILHOUETTE) {
+            // Draw rings
+            if (super.drawStyle == GLU_LINE) {
+                z = 0.0f;
+                r = baseRadius;
+                for (int j = 0; j <= stacks; j++) {
+                    GLStateManager.glBegin(GL_LINE_LOOP);
+                    for (int i = 0; i < slices; i++) {
+                        x = cos(i * da);
+                        y = sin(i * da);
+                        emitNormal(x * nsign, y * nsign, nz * nsign);
+                        GLStateManager.glVertex3f(x * r, y * r, z);
+                    }
+                    GLStateManager.glEnd();
+                    z += dz;
+                    r += dr;
+                }
+            } else {
+                // draw one ring at each end
+                if (baseRadius != 0.0) {
+                    GLStateManager.glBegin(GL_LINE_LOOP);
+                    for (int i = 0; i < slices; i++) {
+                        x = cos(i * da);
+                        y = sin(i * da);
+                        emitNormal(x * nsign, y * nsign, nz * nsign);
+                        GLStateManager.glVertex3f(x * baseRadius, y * baseRadius, 0.0f);
+                    }
+                    GLStateManager.glEnd();
+                    GLStateManager.glBegin(GL_LINE_LOOP);
+                    for (int i = 0; i < slices; i++) {
+                        x = cos(i * da);
+                        y = sin(i * da);
+                        emitNormal(x * nsign, y * nsign, nz * nsign);
+                        GLStateManager.glVertex3f(x * topRadius, y * topRadius, height);
+                    }
+                    GLStateManager.glEnd();
+                }
+            }
+            // draw length lines
+            GLStateManager.glBegin(GL_LINES);
+            for (int i = 0; i < slices; i++) {
+                x = cos(i * da);
+                y = sin(i * da);
+                emitNormal(x * nsign, y * nsign, nz * nsign);
+                GLStateManager.glVertex3f(x * baseRadius, y * baseRadius, 0.0f);
+                GLStateManager.glVertex3f(x * topRadius, y * topRadius, height);
+            }
+            GLStateManager.glEnd();
+        } else if (super.drawStyle == GLU_FILL) {
+            final float ds = 1.0f / slices;
+            final float dt = 1.0f / stacks;
+            float t = 0.0f;
+            z = 0.0f;
+            r = baseRadius;
+            for (int j = 0; j < stacks; j++) {
+                float s = 0.0f;
+                GLStateManager.glBegin(GL_TRIANGLE_STRIP);
+                for (int i = 0; i <= slices; i++) {
+                    final float angle = (i == slices) ? 0.0f : i * da;
+                    x = sin(angle);
+                    y = cos(angle);
+                    emitNormal(x * nsign, y * nsign, nz * nsign);
+                    emitTexCoord(s, t);
+                    GLStateManager.glVertex3f(x * r, y * r, z);
+                    emitNormal(x * nsign, y * nsign, nz * nsign);
+                    emitTexCoord(s, t + dt);
+                    GLStateManager.glVertex3f(x * (r + dr), y * (r + dr), z + dz);
+                    s += ds;
+                }
+                GLStateManager.glEnd();
+                r += dr;
+                t += dt;
+                z += dz;
+            }
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/compat/lwjgl/AngelicaDisk.java

@@ -0,0 +1,134 @@
+package com.gtnewhorizons.angelica.glsm.compat.lwjgl;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.lwjgl.util.glu.Disk;
+
+import static org.lwjgl.opengl.GL11.GL_LINE_LOOP;
+import static org.lwjgl.opengl.GL11.GL_LINE_STRIP;
+import static org.lwjgl.opengl.GL11.GL_POINTS;
+import static org.lwjgl.opengl.GL11.GL_TRIANGLE_STRIP;
+import static org.lwjgl.util.glu.GLU.GLU_FILL;
+import static org.lwjgl.util.glu.GLU.GLU_LINE;
+import static org.lwjgl.util.glu.GLU.GLU_NONE;
+import static org.lwjgl.util.glu.GLU.GLU_OUTSIDE;
+import static org.lwjgl.util.glu.GLU.GLU_POINT;
+import static org.lwjgl.util.glu.GLU.GLU_SILHOUETTE;
+
+/**
+ * Core-profile compatible replacement for {@link Disk}.
+ */
+@SuppressWarnings("unused")
+public class AngelicaDisk extends Disk {
+
+    private static final float PI = (float) Math.PI;
+
+    private void emitTexCoord(float x, float y) {
+        if (super.textureFlag) GLStateManager.glTexCoord2f(x, y);
+    }
+
+    @Override
+    public void draw(float innerRadius, float outerRadius, int slices, int loops) {
+        final float da, dr;
+
+        if (super.normals != GLU_NONE) {
+            GLStateManager.glNormal3f(0.0f, 0.0f, (super.orientation == GLU_OUTSIDE) ? 1.0f : -1.0f);
+        }
+
+        da = 2.0f * PI / slices;
+        dr = (outerRadius - innerRadius) / loops;
+
+        switch (super.drawStyle) {
+            case GLU_FILL -> {
+                final float dtc = 2.0f * outerRadius;
+                float sa, ca;
+                float r1 = innerRadius;
+                for (int l = 0; l < loops; l++) {
+                    final float r2 = r1 + dr;
+                    if (super.orientation == GLU_OUTSIDE) {
+                        GLStateManager.glBegin(GL_TRIANGLE_STRIP);
+                        for (int s = 0; s <= slices; s++) {
+                            final float a = (s == slices) ? 0.0f : s * da;
+                            sa = sin(a);
+                            ca = cos(a);
+                            emitTexCoord(0.5f + sa * r2 / dtc, 0.5f + ca * r2 / dtc);
+                            GLStateManager.glVertex2f(r2 * sa, r2 * ca);
+                            emitTexCoord(0.5f + sa * r1 / dtc, 0.5f + ca * r1 / dtc);
+                            GLStateManager.glVertex2f(r1 * sa, r1 * ca);
+                        }
+                        GLStateManager.glEnd();
+                    } else {
+                        GLStateManager.glBegin(GL_TRIANGLE_STRIP);
+                        for (int s = slices; s >= 0; s--) {
+                            final float a = (s == slices) ? 0.0f : s * da;
+                            sa = sin(a);
+                            ca = cos(a);
+                            emitTexCoord(0.5f - sa * r2 / dtc, 0.5f + ca * r2 / dtc);
+                            GLStateManager.glVertex2f(r2 * sa, r2 * ca);
+                            emitTexCoord(0.5f - sa * r1 / dtc, 0.5f + ca * r1 / dtc);
+                            GLStateManager.glVertex2f(r1 * sa, r1 * ca);
+                        }
+                        GLStateManager.glEnd();
+                    }
+                    r1 = r2;
+                }
+            }
+            case GLU_LINE -> {
+                /* draw loops */
+                for (int l = 0; l <= loops; l++) {
+                    final float r = innerRadius + l * dr;
+                    GLStateManager.glBegin(GL_LINE_LOOP);
+                    for (int s = 0; s < slices; s++) {
+                        final float a = s * da;
+                        GLStateManager.glVertex2f(r * sin(a), r * cos(a));
+                    }
+                    GLStateManager.glEnd();
+                }
+                /* draw spokes */
+                for (int s = 0; s < slices; s++) {
+                    final float a = s * da;
+                    final float x = sin(a);
+                    final float y = cos(a);
+                    GLStateManager.glBegin(GL_LINE_STRIP);
+                    for (int l = 0; l <= loops; l++) {
+                        final float r = innerRadius + l * dr;
+                        GLStateManager.glVertex2f(r * x, r * y);
+                    }
+                    GLStateManager.glEnd();
+                }
+            }
+            case GLU_POINT -> {
+                GLStateManager.glBegin(GL_POINTS);
+                for (int s = 0; s < slices; s++) {
+                    final float a = s * da;
+                    final float x = sin(a);
+                    final float y = cos(a);
+                    for (int l = 0; l <= loops; l++) {
+                        final float r = innerRadius * l * dr;
+                        GLStateManager.glVertex2f(r * x, r * y);
+                    }
+                }
+                GLStateManager.glEnd();
+            }
+            case GLU_SILHOUETTE -> {
+                if (innerRadius != 0.0) {
+                    GLStateManager.glBegin(GL_LINE_LOOP);
+                    for (float a = 0.0f; a < 2.0 * PI; a += da) {
+                        final float x = innerRadius * sin(a);
+                        final float y = innerRadius * cos(a);
+                        GLStateManager.glVertex2f(x, y);
+                    }
+                    GLStateManager.glEnd();
+                }
+                GLStateManager.glBegin(GL_LINE_LOOP);
+                for (float a = 0; a < 2.0f * PI; a += da) {
+                    final float x = outerRadius * sin(a);
+                    final float y = outerRadius * cos(a);
+                    GLStateManager.glVertex2f(x, y);
+                }
+                GLStateManager.glEnd();
+            }
+            default -> {
+            }
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/compat/lwjgl/AngelicaPartialDisk.java

@@ -0,0 +1,243 @@
+package com.gtnewhorizons.angelica.glsm.compat.lwjgl;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.lwjgl.util.glu.PartialDisk;
+
+import static org.lwjgl.opengl.GL11.GL_LINE_STRIP;
+import static org.lwjgl.opengl.GL11.GL_POINTS;
+import static org.lwjgl.opengl.GL11.GL_TRIANGLE_FAN;
+import static org.lwjgl.opengl.GL11.GL_TRIANGLE_STRIP;
+import static org.lwjgl.util.glu.GLU.GLU_FILL;
+import static org.lwjgl.util.glu.GLU.GLU_FLAT;
+import static org.lwjgl.util.glu.GLU.GLU_LINE;
+import static org.lwjgl.util.glu.GLU.GLU_OUTSIDE;
+import static org.lwjgl.util.glu.GLU.GLU_POINT;
+import static org.lwjgl.util.glu.GLU.GLU_SILHOUETTE;
+import static org.lwjgl.util.glu.GLU.GLU_SMOOTH;
+
+/**
+ * Core-profile compatible replacement for {@link PartialDisk}.
+ */
+@SuppressWarnings("unused")
+public class AngelicaPartialDisk extends PartialDisk {
+
+    private static final float PI = (float) Math.PI;
+    private static final int CACHE_SIZE = 240;
+    private final float[] sinCache = new float[CACHE_SIZE];
+    private final float[] cosCache = new float[CACHE_SIZE];
+
+    @Override
+    public void draw(float innerRadius, float outerRadius, int slices, int loops, float startAngle, float sweepAngle) {
+        final float deltaRadius, angleOffset;
+        float angle, sintemp, costemp, radiusLow, radiusHigh, texLow = 0, texHigh = 0;
+        final int slices2, finish;
+
+        if (slices >= CACHE_SIZE) slices = CACHE_SIZE - 1;
+        if (slices < 2 || loops < 1 || outerRadius <= 0.0f || innerRadius < 0.0f || innerRadius > outerRadius) {
+            GLStateManager.LOGGER.warn("PartialDisk: GLU_INVALID_VALUE (slices={}, loops={}, innerRadius={}, outerRadius={})", slices, loops, innerRadius, outerRadius);
+            return;
+        }
+
+        if (sweepAngle < -360.0f) sweepAngle = 360.0f;
+        if (sweepAngle > 360.0f) sweepAngle = 360.0f;
+        if (sweepAngle < 0) {
+            startAngle += sweepAngle;
+            sweepAngle = -sweepAngle;
+        }
+
+        slices2 = (sweepAngle == 360.0f) ? slices : slices + 1;
+
+        /* Compute length (needed for normal calculations) */
+        deltaRadius = outerRadius - innerRadius;
+
+        angleOffset = startAngle / 180.0f * PI;
+        for (int i = 0; i <= slices; i++) {
+            angle = angleOffset + ((PI * sweepAngle) / 180.0f) * i / slices;
+            sinCache[i] = sin(angle);
+            cosCache[i] = cos(angle);
+        }
+
+        if (sweepAngle == 360.0f) {
+            sinCache[slices] = sinCache[0];
+            cosCache[slices] = cosCache[0];
+        }
+
+        switch (super.normals) {
+            case GLU_FLAT, GLU_SMOOTH -> GLStateManager.glNormal3f(0.0f, 0.0f, (super.orientation == GLU_OUTSIDE) ? 1.0f : -1.0f);
+            default -> {
+            }
+        }
+
+        switch (super.drawStyle) {
+            case GLU_FILL -> {
+                if (innerRadius == .0f) {
+                    finish = loops - 1;
+                    /* Triangle strip for inner polygons */
+                    GLStateManager.glBegin(GL_TRIANGLE_FAN);
+                    if (super.textureFlag) {
+                        GLStateManager.glTexCoord2f(0.5f, 0.5f);
+                    }
+                    GLStateManager.glVertex3f(0.0f, 0.0f, 0.0f);
+                    radiusLow = outerRadius - deltaRadius * ((float) (loops - 1) / loops);
+                    if (super.textureFlag) {
+                        texLow = radiusLow / outerRadius / 2;
+                    }
+
+                    if (super.orientation == GLU_OUTSIDE) {
+                        for (int i = slices; i >= 0; i--) {
+                            if (super.textureFlag) {
+                                GLStateManager.glTexCoord2f(texLow * sinCache[i] + 0.5f, texLow * cosCache[i] + 0.5f);
+                            }
+                            GLStateManager.glVertex3f(radiusLow * sinCache[i], radiusLow * cosCache[i], 0.0f);
+                        }
+                    } else {
+                        for (int i = 0; i <= slices; i++) {
+                            if (super.textureFlag) {
+                                GLStateManager.glTexCoord2f(texLow * sinCache[i] + 0.5f, texLow * cosCache[i] + 0.5f);
+                            }
+                            GLStateManager.glVertex3f(radiusLow * sinCache[i], radiusLow * cosCache[i], 0.0f);
+                        }
+                    }
+                    GLStateManager.glEnd();
+                } else {
+                    finish = loops;
+                }
+                for (int j = 0; j < finish; j++) {
+                    radiusLow = outerRadius - deltaRadius * ((float) j / loops);
+                    radiusHigh = outerRadius - deltaRadius * ((float) (j + 1) / loops);
+                    if (super.textureFlag) {
+                        texLow = radiusLow / outerRadius / 2;
+                        texHigh = radiusHigh / outerRadius / 2;
+                    }
+
+                    GLStateManager.glBegin(GL_TRIANGLE_STRIP);
+                    for (int i = 0; i <= slices; i++) {
+                        if (super.orientation == GLU_OUTSIDE) {
+                            if (super.textureFlag) {
+                                GLStateManager.glTexCoord2f(texLow * sinCache[i] + 0.5f, texLow * cosCache[i] + 0.5f);
+                            }
+                            GLStateManager.glVertex3f(radiusLow * sinCache[i], radiusLow * cosCache[i], 0.0f);
+
+                            if (super.textureFlag) {
+                                GLStateManager.glTexCoord2f(texHigh * sinCache[i] + 0.5f, texHigh * cosCache[i] + 0.5f);
+                            }
+                            GLStateManager.glVertex3f(radiusHigh * sinCache[i], radiusHigh * cosCache[i], 0.0f);
+                        } else {
+                            if (super.textureFlag) {
+                                GLStateManager.glTexCoord2f(texHigh * sinCache[i] + 0.5f, texHigh * cosCache[i] + 0.5f);
+                            }
+                            GLStateManager.glVertex3f(radiusHigh * sinCache[i], radiusHigh * cosCache[i], 0.0f);
+
+                            if (super.textureFlag) {
+                                GLStateManager.glTexCoord2f(texLow * sinCache[i] + 0.5f, texLow * cosCache[i] + 0.5f);
+                            }
+                            GLStateManager.glVertex3f(radiusLow * sinCache[i], radiusLow * cosCache[i], 0.0f);
+                        }
+                    }
+                    GLStateManager.glEnd();
+                }
+            }
+            case GLU_POINT -> {
+                GLStateManager.glBegin(GL_POINTS);
+                for (int i = 0; i < slices2; i++) {
+                    sintemp = sinCache[i];
+                    costemp = cosCache[i];
+                    for (int j = 0; j <= loops; j++) {
+                        radiusLow = outerRadius - deltaRadius * ((float) j / loops);
+
+                        if (super.textureFlag) {
+                            texLow = radiusLow / outerRadius / 2;
+
+                            GLStateManager.glTexCoord2f(texLow * sinCache[i] + 0.5f, texLow * cosCache[i] + 0.5f);
+                        }
+                        GLStateManager.glVertex3f(radiusLow * sintemp, radiusLow * costemp, 0.0f);
+                    }
+                }
+                GLStateManager.glEnd();
+            }
+            case GLU_LINE -> {
+                if (innerRadius == outerRadius) {
+                    GLStateManager.glBegin(GL_LINE_STRIP);
+
+                    for (int i = 0; i <= slices; i++) {
+                        if (super.textureFlag) {
+                            GLStateManager.glTexCoord2f(sinCache[i] / 2 + 0.5f, cosCache[i] / 2 + 0.5f);
+                        }
+                        GLStateManager.glVertex3f(innerRadius * sinCache[i], innerRadius * cosCache[i], 0.0f);
+                    }
+                    GLStateManager.glEnd();
+                    break;
+                }
+                for (int j = 0; j <= loops; j++) {
+                    radiusLow = outerRadius - deltaRadius * ((float) j / loops);
+                    if (super.textureFlag) {
+                        texLow = radiusLow / outerRadius / 2;
+                    }
+
+                    GLStateManager.glBegin(GL_LINE_STRIP);
+                    for (int i = 0; i <= slices; i++) {
+                        if (super.textureFlag) {
+                            GLStateManager.glTexCoord2f(texLow * sinCache[i] + 0.5f, texLow * cosCache[i] + 0.5f);
+                        }
+                        GLStateManager.glVertex3f(radiusLow * sinCache[i], radiusLow * cosCache[i], 0.0f);
+                    }
+                    GLStateManager.glEnd();
+                }
+                for (int i = 0; i < slices2; i++) {
+                    sintemp = sinCache[i];
+                    costemp = cosCache[i];
+                    GLStateManager.glBegin(GL_LINE_STRIP);
+                    for (int j = 0; j <= loops; j++) {
+                        radiusLow = outerRadius - deltaRadius * ((float) j / loops);
+                        if (super.textureFlag) {
+                            texLow = radiusLow / outerRadius / 2;
+                        }
+
+                        if (super.textureFlag) {
+                            GLStateManager.glTexCoord2f(texLow * sinCache[i] + 0.5f, texLow * cosCache[i] + 0.5f);
+                        }
+                        GLStateManager.glVertex3f(radiusLow * sintemp, radiusLow * costemp, 0.0f);
+                    }
+                    GLStateManager.glEnd();
+                }
+            }
+            case GLU_SILHOUETTE -> {
+                if (sweepAngle < 360.0f) {
+                    for (int i = 0; i <= slices; i += slices) {
+                        sintemp = sinCache[i];
+                        costemp = cosCache[i];
+                        GLStateManager.glBegin(GL_LINE_STRIP);
+                        for (int j = 0; j <= loops; j++) {
+                            radiusLow = outerRadius - deltaRadius * ((float) j / loops);
+
+                            if (super.textureFlag) {
+                                texLow = radiusLow / outerRadius / 2;
+                                GLStateManager.glTexCoord2f(texLow * sinCache[i] + 0.5f, texLow * cosCache[i] + 0.5f);
+                            }
+                            GLStateManager.glVertex3f(radiusLow * sintemp, radiusLow * costemp, 0.0f);
+                        }
+                        GLStateManager.glEnd();
+                    }
+                }
+                for (int j = 0; j <= loops; j += loops) {
+                    radiusLow = outerRadius - deltaRadius * ((float) j / loops);
+                    if (super.textureFlag) {
+                        texLow = radiusLow / outerRadius / 2;
+                    }
+
+                    GLStateManager.glBegin(GL_LINE_STRIP);
+                    for (int i = 0; i <= slices; i++) {
+                        if (super.textureFlag) {
+                            GLStateManager.glTexCoord2f(texLow * sinCache[i] + 0.5f, texLow * cosCache[i] + 0.5f);
+                        }
+                        GLStateManager.glVertex3f(radiusLow * sinCache[i], radiusLow * cosCache[i], 0.0f);
+                    }
+                    GLStateManager.glEnd();
+                    if (innerRadius == outerRadius) break;
+                }
+            }
+            default -> {
+            }
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/compat/lwjgl/AngelicaSphere.java

@@ -0,0 +1,183 @@
+package com.gtnewhorizons.angelica.glsm.compat.lwjgl;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.lwjgl.util.glu.Sphere;
+
+import static org.lwjgl.opengl.GL11.GL_LINE_LOOP;
+import static org.lwjgl.opengl.GL11.GL_LINE_STRIP;
+import static org.lwjgl.opengl.GL11.GL_POINTS;
+import static org.lwjgl.opengl.GL11.GL_TRIANGLE_FAN;
+import static org.lwjgl.opengl.GL11.GL_TRIANGLE_STRIP;
+import static org.lwjgl.util.glu.GLU.GLU_FILL;
+import static org.lwjgl.util.glu.GLU.GLU_INSIDE;
+import static org.lwjgl.util.glu.GLU.GLU_LINE;
+import static org.lwjgl.util.glu.GLU.GLU_NONE;
+import static org.lwjgl.util.glu.GLU.GLU_POINT;
+import static org.lwjgl.util.glu.GLU.GLU_SILHOUETTE;
+
+/**
+ * Core-profile compatible replacement for {@link Sphere}.
+ */
+@SuppressWarnings("unused")
+public class AngelicaSphere extends Sphere {
+
+    private static final float PI = (float) Math.PI;
+
+    private void emitNormal(float x, float y, float z) {
+        final float mag = (float) Math.sqrt(x * x + y * y + z * z);
+        if (mag > 0.00001F) {
+            x /= mag;
+            y /= mag;
+            z /= mag;
+        }
+        GLStateManager.glNormal3f(x, y, z);
+    }
+
+    private void emitTexCoord(float x, float y) {
+        if (super.textureFlag) GLStateManager.glTexCoord2f(x, y);
+    }
+
+    @Override
+    public void draw(float radius, int slices, int stacks) {
+        final float drho, dtheta, ds, dt, nsign;
+        float rho, theta, x, y, z, s, t;
+
+        final int imin, imax;
+        final boolean normals;
+
+        normals = super.normals != GLU_NONE;
+        nsign = (super.orientation == GLU_INSIDE) ? -1.0f : 1.0f;
+
+        drho = PI / stacks;
+        dtheta = 2.0f * PI / slices;
+
+        if (super.drawStyle == GLU_FILL) {
+            if (!super.textureFlag) {
+                // draw +Z end as a triangle fan
+                GLStateManager.glBegin(GL_TRIANGLE_FAN);
+                GLStateManager.glNormal3f(0.0f, 0.0f, 1.0f);
+                GLStateManager.glVertex3f(0.0f, 0.0f, nsign * radius);
+                for (int j = 0; j <= slices; j++) {
+                    theta = (j == slices) ? 0.0f : j * dtheta;
+                    x = -sin(theta) * sin(drho);
+                    y = cos(theta) * sin(drho);
+                    z = nsign * cos(drho);
+                    if (normals) {
+                        emitNormal(x * nsign, y * nsign, z * nsign);
+                    }
+                    GLStateManager.glVertex3f(x * radius, y * radius, z * radius);
+                }
+                GLStateManager.glEnd();
+            }
+
+            ds = 1.0f / slices;
+            dt = 1.0f / stacks;
+            t = 1.0f;
+            if (super.textureFlag) {
+                imin = 0;
+                imax = stacks;
+            } else {
+                imin = 1;
+                imax = stacks - 1;
+            }
+
+            // draw intermediate stacks as triangle strips (GL_QUAD_STRIP removed in core profile)
+            for (int i = imin; i < imax; i++) {
+                rho = i * drho;
+                GLStateManager.glBegin(GL_TRIANGLE_STRIP);
+                s = 0.0f;
+                for (int j = 0; j <= slices; j++) {
+                    theta = (j == slices) ? 0.0f : j * dtheta;
+                    x = -sin(theta) * sin(rho);
+                    y = cos(theta) * sin(rho);
+                    z = nsign * cos(rho);
+                    if (normals) {
+                        emitNormal(x * nsign, y * nsign, z * nsign);
+                    }
+                    emitTexCoord(s, t);
+                    GLStateManager.glVertex3f(x * radius, y * radius, z * radius);
+                    x = -sin(theta) * sin(rho + drho);
+                    y = cos(theta) * sin(rho + drho);
+                    z = nsign * cos(rho + drho);
+                    if (normals) {
+                        emitNormal(x * nsign, y * nsign, z * nsign);
+                    }
+                    emitTexCoord(s, t - dt);
+                    s += ds;
+                    GLStateManager.glVertex3f(x * radius, y * radius, z * radius);
+                }
+                GLStateManager.glEnd();
+                t -= dt;
+            }
+
+            if (!super.textureFlag) {
+                // draw -Z end as a triangle fan
+                GLStateManager.glBegin(GL_TRIANGLE_FAN);
+                GLStateManager.glNormal3f(0.0f, 0.0f, -1.0f);
+                GLStateManager.glVertex3f(0.0f, 0.0f, -radius * nsign);
+                rho = PI - drho;
+                s = 1.0f;
+                for (int j = slices; j >= 0; j--) {
+                    theta = (j == slices) ? 0.0f : j * dtheta;
+                    x = -sin(theta) * sin(rho);
+                    y = cos(theta) * sin(rho);
+                    z = nsign * cos(rho);
+                    if (normals) emitNormal(x * nsign, y * nsign, z * nsign);
+                    s -= ds;
+                    GLStateManager.glVertex3f(x * radius, y * radius, z * radius);
+                }
+                GLStateManager.glEnd();
+            }
+        } else if (super.drawStyle == GLU_LINE || super.drawStyle == GLU_SILHOUETTE) {
+            // draw stack lines
+            for (int i = 1; i < stacks; i++) {
+                rho = i * drho;
+                GLStateManager.glBegin(GL_LINE_LOOP);
+                for (int j = 0; j < slices; j++) {
+                    theta = j * dtheta;
+                    x = cos(theta) * sin(rho);
+                    y = sin(theta) * sin(rho);
+                    z = cos(rho);
+                    if (normals) emitNormal(x * nsign, y * nsign, z * nsign);
+                    GLStateManager.glVertex3f(x * radius, y * radius, z * radius);
+                }
+                GLStateManager.glEnd();
+            }
+            // draw slice lines
+            for (int j = 0; j < slices; j++) {
+                theta = j * dtheta;
+                GLStateManager.glBegin(GL_LINE_STRIP);
+                for (int i = 0; i <= stacks; i++) {
+                    rho = i * drho;
+                    x = cos(theta) * sin(rho);
+                    y = sin(theta) * sin(rho);
+                    z = cos(rho);
+                    if (normals) emitNormal(x * nsign, y * nsign, z * nsign);
+                    GLStateManager.glVertex3f(x * radius, y * radius, z * radius);
+                }
+                GLStateManager.glEnd();
+            }
+        } else if (super.drawStyle == GLU_POINT) {
+            // top and bottom-most points
+            GLStateManager.glBegin(GL_POINTS);
+            if (normals) GLStateManager.glNormal3f(0.0f, 0.0f, nsign);
+            GLStateManager.glVertex3f(0.0f, 0.0f, radius);
+            if (normals) GLStateManager.glNormal3f(0.0f, 0.0f, -nsign);
+            GLStateManager.glVertex3f(0.0f, 0.0f, -radius);
+
+            // loop over stacks
+            for (int i = 1; i < stacks - 1; i++) {
+                rho = i * drho;
+                for (int j = 0; j < slices; j++) {
+                    theta = j * dtheta;
+                    x = cos(theta) * sin(rho);
+                    y = sin(theta) * sin(rho);
+                    z = cos(rho);
+                    if (normals) emitNormal(x * nsign, y * nsign, z * nsign);
+                    GLStateManager.glVertex3f(x * radius, y * radius, z * radius);
+                }
+            }
+            GLStateManager.glEnd();
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/dsa/DSAARB.java

@@ -0,0 +1,147 @@
+package com.gtnewhorizons.angelica.glsm.dsa;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+
+import java.nio.ByteBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+public class DSAARB extends DSAUnsupported {
+
+    @Override
+    public void generateMipmaps(int texture, int target) {
+        RENDER_BACKEND.generateTextureMipmap(texture);
+    }
+
+    @Override
+    public void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, ByteBuffer pixels) {
+        // Note: DSA glTextureImage2D doesn't exist in ARB_direct_state_access
+        // We need to use glTextureStorage2D + glTextureSubImage2D, or fall back to bind-based approach
+        // For simplicity, use the fallback which binds, uploads, and restores
+        super.textureImage2D(texture, target, level, internalformat, width, height, border, format, type, pixels);
+    }
+
+    @Override
+    public void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, IntBuffer pixels) {
+        super.textureImage2D(texture, target, level, internalformat, width, height, border, format, type, pixels);
+    }
+
+    @Override
+    public void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, ByteBuffer pixels) {
+        RENDER_BACKEND.textureSubImage2D(texture, level, xoffset, yoffset, width, height, format, type, pixels);
+    }
+
+    @Override
+    public void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, IntBuffer pixels) {
+        RENDER_BACKEND.textureSubImage2D(texture, level, xoffset, yoffset, width, height, format, type, pixels);
+    }
+
+    @Override
+    public void texParameteri(int texture, int target, int pname, int param) {
+        param = GLStateManager.remapTexClamp(pname, param);
+        if(!GLStateManager.updateTexParameteriCache(target, texture, pname, param)) return;
+
+        RENDER_BACKEND.textureParameteri(texture, target, pname, param);
+    }
+
+    @Override
+    public void texParameterf(int texture, int target, int pname, float param) {
+        param = GLStateManager.remapTexClamp(pname, param);
+        if(!GLStateManager.updateTexParameterfCache(target, texture, pname, param)) return;
+
+        RENDER_BACKEND.textureParameterf(texture, target, pname, param);
+    }
+
+    @Override
+    public void texParameteriv(int texture, int target, int pname, IntBuffer params) {
+        GLStateManager.remapTexClampBuffer(pname, params);
+        RENDER_BACKEND.textureParameteriv(texture, target, pname, params);
+    }
+
+    @Override
+    public void readBuffer(int framebuffer, int buffer) {
+        RENDER_BACKEND.namedFramebufferReadBuffer(framebuffer, buffer);
+    }
+
+    @Override
+    public void drawBuffers(int framebuffer, IntBuffer buffers) {
+        RENDER_BACKEND.namedFramebufferDrawBuffers(framebuffer, buffers);
+    }
+
+    @Override
+    public int getTexParameteri(int texture, int target, int pname) {
+        return GLStateManager.getTexParameterOrDefault(texture, pname, () -> RENDER_BACKEND.getTextureParameteri(texture, target, pname));
+    }
+
+    @Override
+    public int getTexLevelParameteri(int texture, int level, int pname) {
+        return RENDER_BACKEND.getTextureLevelParameteri(texture, level, pname);
+    }
+
+    @Override
+    public void copyTexSubImage2D(int destTexture, int target, int i, int i1, int i2, int i3, int i4, int width, int height) {
+        RENDER_BACKEND.copyTextureSubImage2D(destTexture, target, i, i1, i2, i3, i4, width, height);
+    }
+
+    @Override
+    public void bindTextureToUnit(int unit, int texture) {
+        if(GLStateManager.getBoundTextureForServerState(unit) == texture) return;
+
+        if (texture == 0) {
+            super.bindTextureToUnit(unit, texture);
+        } else {
+            RENDER_BACKEND.bindTextureUnit(unit, texture);
+            GLStateManager.getTextures().getTextureUnitBindings(unit).setBinding(texture);
+        }
+    }
+
+    @Override
+    public void bindTextureToUnit(int target, int unit, int texture) {
+        bindTextureToUnit(unit, texture);
+    }
+
+    @Override
+    public int bufferStorage(int target, FloatBuffer data, int usage) {
+        final int buffer = GLStateManager.glCreateBuffers();
+        GLStateManager.glNamedBufferData(buffer, data, usage);
+        return buffer;
+    }
+
+    @Override
+    public void blitFramebuffer(int source, int dest, int offsetX, int offsetY, int width, int height, int offsetX2, int offsetY2, int width2, int height2,
+        int bufferChoice, int filter) {
+        RENDER_BACKEND.blitNamedFramebuffer(source, dest, offsetX, offsetY, width, height, offsetX2, offsetY2, width2, height2, bufferChoice, filter);
+    }
+
+    @Override
+    public void framebufferTexture2D(int fb, int fbtarget, int attachment, int target, int texture, int levels) {
+        RENDER_BACKEND.namedFramebufferTexture(fb, attachment, texture, levels);
+    }
+
+    @Override
+    public int createFramebuffer() {
+        return RENDER_BACKEND.createFramebuffers();
+    }
+
+    @Override
+    public int createTexture(int target) {
+        return RENDER_BACKEND.createTextures(target);
+    }
+
+    @Override
+    public void textureStorage1D(int texture, int target, int levels, int internalFormat, int width) {
+        RENDER_BACKEND.textureStorage1D(texture, levels, internalFormat, width);
+    }
+
+    @Override
+    public void textureStorage2D(int texture, int target, int levels, int internalFormat, int width, int height) {
+        RENDER_BACKEND.textureStorage2D(texture, levels, internalFormat, width, height);
+    }
+
+    @Override
+    public void textureStorage3D(int texture, int target, int levels, int internalFormat, int width, int height, int depth) {
+        RENDER_BACKEND.textureStorage3D(texture, levels, internalFormat, width, height, depth);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/dsa/DSAAccess.java

@@ -0,0 +1,46 @@
+package com.gtnewhorizons.angelica.glsm.dsa;
+
+import java.nio.ByteBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+
+public interface DSAAccess {
+    void generateMipmaps(int texture, int target);
+
+    // Texture image upload - DSA allows specifying texture directly without binding
+    void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, ByteBuffer pixels);
+    void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, IntBuffer pixels);
+    void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, ByteBuffer pixels);
+    void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, IntBuffer pixels);
+
+    void texParameteri(int texture, int target, int pname, int param);
+    void texParameterf(int texture, int target, int pname, float param);
+    void texParameteriv(int texture, int target, int pname, IntBuffer params);
+
+    void readBuffer(int framebuffer, int buffer);
+
+    void drawBuffers(int framebuffer, IntBuffer buffers);
+
+    int getTexParameteri(int texture, int target, int pname);
+
+    int getTexLevelParameteri(int texture, int level, int pname);
+
+    void copyTexSubImage2D(int destTexture, int target, int i, int i1, int i2, int i3, int i4, int width, int height);
+
+    void bindTextureToUnit(int unit, int texture);
+    void bindTextureToUnit(int target, int unit, int texture);
+
+    int bufferStorage(int target, FloatBuffer data, int usage);
+
+    void blitFramebuffer(int source, int dest, int offsetX, int offsetY, int width, int height, int offsetX2, int offsetY2, int width2, int height2, int bufferChoice, int filter);
+
+    void framebufferTexture2D(int fb, int fbtarget, int attachment, int target, int texture, int levels);
+
+    int createFramebuffer();
+    int createTexture(int target);
+
+    // Texture storage methods for custom images
+    void textureStorage1D(int texture, int target, int levels, int internalFormat, int width);
+    void textureStorage2D(int texture, int target, int levels, int internalFormat, int width, int height);
+    void textureStorage3D(int texture, int target, int levels, int internalFormat, int width, int height, int depth);
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/dsa/DSAEXT.java

@@ -0,0 +1,18 @@
+package com.gtnewhorizons.angelica.glsm.dsa;
+
+import java.nio.ByteBuffer;
+import java.nio.IntBuffer;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+public class DSAEXT extends DSACore {
+    @Override
+    public void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, ByteBuffer pixels) {
+        RENDER_BACKEND.textureImage2DEXT(texture, target, level, internalformat, width, height, border, format, type, pixels);
+    }
+
+    @Override
+    public void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, IntBuffer pixels) {
+        RENDER_BACKEND.textureImage2DEXT(texture, target, level, internalformat, width, height, border, format, type, pixels);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/dsa/DSAUnsupported.java

@@ -0,0 +1,183 @@
+package com.gtnewhorizons.angelica.glsm.dsa;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.lwjgl.opengl.GL11;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+import org.lwjgl.opengl.GL12;
+import org.lwjgl.opengl.GL13;
+import org.lwjgl.opengl.GL30;
+import org.lwjgl.opengl.GL31;
+
+import java.nio.ByteBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+
+public class DSAUnsupported implements DSAAccess {
+
+    @Override
+    public void generateMipmaps(int texture, int target) {
+        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
+        RENDER_BACKEND.generateMipmap(target);
+    }
+
+    @Override
+    public void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, ByteBuffer pixels) {
+        // Get what cache thinks is bound - we'll restore to this to keep cache/GL in sync
+        final int cachedBinding = GLStateManager.getBoundTextureForServerState();
+        RENDER_BACKEND.bindTexture(target, texture);
+        RENDER_BACKEND.texImage2D(target, level, internalformat, width, height, border, format, type, pixels);
+        RENDER_BACKEND.bindTexture(target, cachedBinding); // Restore to cache value
+    }
+
+    @Override
+    public void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, IntBuffer pixels) {
+        final int cachedBinding = GLStateManager.getBoundTextureForServerState();
+        RENDER_BACKEND.bindTexture(target, texture);
+        RENDER_BACKEND.texImage2D(target, level, internalformat, width, height, border, format, type, pixels);
+        RENDER_BACKEND.bindTexture(target, cachedBinding);
+    }
+
+    @Override
+    public void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, ByteBuffer pixels) {
+        final int cachedBinding = GLStateManager.getBoundTextureForServerState();
+        RENDER_BACKEND.bindTexture(target, texture);
+        RENDER_BACKEND.texSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);
+        RENDER_BACKEND.bindTexture(target, cachedBinding);
+    }
+
+    @Override
+    public void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, IntBuffer pixels) {
+        final int cachedBinding = GLStateManager.getBoundTextureForServerState();
+        RENDER_BACKEND.bindTexture(target, texture);
+        RENDER_BACKEND.texSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);
+        RENDER_BACKEND.bindTexture(target, cachedBinding);
+    }
+
+    @Override
+    public void texParameteri(int texture, int target, int pname, int param) {
+        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
+        GLStateManager.glTexParameteri(target, pname, param);
+    }
+
+    @Override
+    public void texParameterf(int texture, int target, int pname, float param) {
+        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
+        GLStateManager.glTexParameterf(target, pname, param);
+    }
+
+    @Override
+    public void texParameteriv(int texture, int target, int pname, IntBuffer params) {
+        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
+        GLStateManager.glTexParameter(target, pname, params);
+    }
+
+    @Override
+    public void readBuffer(int framebuffer, int buffer) {
+        GLStateManager.glBindFramebuffer(GL30.GL_FRAMEBUFFER, framebuffer);
+        RENDER_BACKEND.readBuffer(buffer);
+    }
+
+    @Override
+    public void drawBuffers(int framebuffer, IntBuffer buffers) {
+        GLStateManager.glBindFramebuffer(GL30.GL_FRAMEBUFFER, framebuffer);
+        RENDER_BACKEND.drawBuffers(buffers);
+    }
+
+    @Override
+    public int getTexParameteri(int texture, int target, int pname) {
+        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
+        return GLStateManager.glGetTexParameteri(target, pname);
+    }
+
+    @Override
+    public int getTexLevelParameteri(int texture, int level, int pname) {
+        final int previous = GLStateManager.getBoundTextureForServerState();
+        RENDER_BACKEND.bindTexture(GL11.GL_TEXTURE_2D, texture);
+        final int result = RENDER_BACKEND.getTexLevelParameteri(GL11.GL_TEXTURE_2D, level, pname);
+        RENDER_BACKEND.bindTexture(GL11.GL_TEXTURE_2D, previous);
+        return result;
+    }
+
+    @Override
+    public void copyTexSubImage2D(int destTexture, int target, int i, int i1, int i2, int i3, int i4, int width, int height) {
+        final int previous = GLStateManager.getBoundTextureForServerState();
+        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, destTexture);
+        RENDER_BACKEND.copyTexSubImage2D(target, i, i1, i2, i3, i4, width, height);
+        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, previous);
+    }
+
+    @Override
+    public void bindTextureToUnit(int unit, int texture) {
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE0 + unit);
+        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
+    }
+
+    @Override
+    public void bindTextureToUnit(int target, int unit, int texture) {
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE0 + unit);
+        GLStateManager.glBindTexture(target, texture);
+    }
+
+    @Override
+    public int bufferStorage(int target, FloatBuffer data, int usage) {
+        final int buffer = GLStateManager.glGenBuffers();
+        GLStateManager.glBindBuffer(target, buffer);
+        GLStateManager.glBufferData(target, data, usage);
+        GLStateManager.glBindBuffer(target, 0);
+
+        return buffer;
+    }
+
+    @Override
+    public void blitFramebuffer(int source, int dest, int offsetX, int offsetY, int width, int height, int offsetX2, int offsetY2, int width2, int height2,
+        int bufferChoice, int filter) {
+        GLStateManager.glBindFramebuffer(GL30.GL_READ_FRAMEBUFFER, source);
+        GLStateManager.glBindFramebuffer(GL30.GL_DRAW_FRAMEBUFFER, dest);
+        RENDER_BACKEND.blitFramebuffer(offsetX, offsetY, width, height, offsetX2, offsetY2, width2, height2, bufferChoice, filter);
+    }
+
+    @Override
+    public void framebufferTexture2D(int fb, int fbtarget, int attachment, int target, int texture, int levels) {
+        GLStateManager.glBindFramebuffer(fbtarget, fb);
+        RENDER_BACKEND.framebufferTexture2D(fbtarget, attachment, target, texture, levels);
+    }
+
+    @Override
+    public int createFramebuffer() {
+        final int framebuffer = GLStateManager.glGenFramebuffers();
+        GLStateManager.glBindFramebuffer(GL30.GL_FRAMEBUFFER, framebuffer);
+        return framebuffer;
+    }
+
+    @Override
+    public int createTexture(int target) {
+        final int texture = RENDER_BACKEND.genTextures();
+        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
+        return texture;
+    }
+
+    @Override
+    public void textureStorage1D(int texture, int target, int levels, int internalFormat, int width) {
+        final int previous = RENDER_BACKEND.getInteger(GL11.GL_TEXTURE_BINDING_1D);
+        RENDER_BACKEND.bindTexture(target, texture);
+        RENDER_BACKEND.texStorage1D(target, levels, internalFormat, width);
+        RENDER_BACKEND.bindTexture(target, previous);
+    }
+
+    @Override
+    public void textureStorage2D(int texture, int target, int levels, int internalFormat, int width, int height) {
+        final int previous = (target == GL11.GL_TEXTURE_2D) ? GLStateManager.getBoundTextureForServerState() : RENDER_BACKEND.getInteger(GL31.GL_TEXTURE_BINDING_RECTANGLE);
+        RENDER_BACKEND.bindTexture(target, texture);
+        RENDER_BACKEND.texStorage2D(target, levels, internalFormat, width, height);
+        RENDER_BACKEND.bindTexture(target, previous);
+    }
+
+    @Override
+    public void textureStorage3D(int texture, int target, int levels, int internalFormat, int width, int height, int depth) {
+        final int previous = RENDER_BACKEND.getInteger(GL12.GL_TEXTURE_BINDING_3D);
+        RENDER_BACKEND.bindTexture(target, texture);
+        RENDER_BACKEND.texStorage3D(target, levels, internalFormat, width, height, depth);
+        RENDER_BACKEND.bindTexture(target, previous);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/FragmentKey.java

@@ -0,0 +1,394 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import java.util.Arrays;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.states.TexEnvState;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL12;
+import org.lwjgl.opengl.GL13;
+
+/**
+ * Packed-long fragment shader permutation key for FFP emulation.
+ *
+ * Layout:
+ *   long[0]: global bits (11) + unit 0 (47 bits at offset 11)
+ *   long[1..3]: unit 1..3 (47 bits each, low-aligned)
+ * Only max(1, nrEnabledUnits) longs are significant.
+ *
+ * Per-unit packing (47 bits):
+ *   0:     enabled
+ *   1-3:   mode (MODULATE=0..COMBINE=5)
+ *   4:     needsEnvColor
+ *   5-8:   combineRgb (encoded 0-7)
+ *   9-12:  combineAlpha (encoded 0-7)
+ *   13-14: scaleShiftRgb
+ *   15-16: scaleShiftAlpha
+ *   17-21: arg0 RGB (source:3 + operand:2)
+ *   22-26: arg1 RGB
+ *   27-31: arg2 RGB
+ *   32-36: arg0 Alpha
+ *   37-41: arg1 Alpha
+ *   42-46: arg2 Alpha
+ */
+public final class FragmentKey {
+    public static final int TEX_ENV_MODULATE = 0;
+    public static final int TEX_ENV_REPLACE  = 1;
+    public static final int TEX_ENV_ADD      = 2;
+    public static final int TEX_ENV_DECAL    = 3;
+    public static final int TEX_ENV_BLEND    = 4;
+    public static final int TEX_ENV_COMBINE  = 5;
+
+    public static final int COMBINE_REPLACE      = 0;
+    public static final int COMBINE_MODULATE     = 1;
+    public static final int COMBINE_ADD          = 2;
+    public static final int COMBINE_ADD_SIGNED   = 3;
+    public static final int COMBINE_INTERPOLATE  = 4;
+    public static final int COMBINE_SUBTRACT     = 5;
+    public static final int COMBINE_DOT3_RGB     = 6;
+    public static final int COMBINE_DOT3_RGBA    = 7;
+
+    public static final int SRC_TEXTURE       = 0;
+    public static final int SRC_CONSTANT      = 1;
+    public static final int SRC_PRIMARY_COLOR = 2;
+    public static final int SRC_PREVIOUS      = 3;
+
+    public static final int OP_SRC_COLOR           = 0;
+    public static final int OP_ONE_MINUS_SRC_COLOR = 1;
+    public static final int OP_SRC_ALPHA           = 2;
+    public static final int OP_ONE_MINUS_SRC_ALPHA = 3;
+
+    public static final int FOG_NONE   = 0;
+    public static final int FOG_LINEAR = 1;
+    public static final int FOG_EXP    = 2;
+    public static final int FOG_EXP2   = 3;
+
+    private static final int GLOBAL_BITS = 11;
+    private static final int BIT_FOG_MODE          = 0;  // 2 bits
+    private static final int BIT_ALPHA_TEST        = 2;  // 1 bit
+    private static final int BIT_ALPHA_FUNC        = 3;  // 3 bits
+    private static final int BIT_SEPARATE_SPECULAR = 6;  // 1 bit
+    private static final int BIT_NR_ENABLED_UNITS  = 7;  // 3 bits
+    private static final int BIT_OVERLAY_ENABLED   = 10; // 1 bit
+
+    private static final int U_ENABLED         = 0;
+    private static final int U_MODE            = 1;   // 3 bits
+    private static final int U_NEEDS_ENV_COLOR = 4;   // 1 bit
+    private static final int U_COMBINE_RGB     = 5;   // 4 bits
+    private static final int U_COMBINE_ALPHA   = 9;   // 4 bits
+    private static final int U_SCALE_RGB       = 13;  // 2 bits
+    private static final int U_SCALE_ALPHA     = 15;  // 2 bits
+    private static final int U_ARG0_RGB        = 17;  // 5 bits (source:3 + operand:2)
+    private static final int U_ARG1_RGB        = 22;  // 5 bits
+    private static final int U_ARG2_RGB        = 27;  // 5 bits
+    private static final int U_ARG0_ALPHA      = 32;  // 5 bits
+    private static final int U_ARG1_ALPHA      = 37;  // 5 bits
+    private static final int U_ARG2_ALPHA      = 42;  // 5 bits
+
+    static final int MAX_UNITS = 4;
+
+    private final long[] packed;
+    private final int hash;
+
+    private FragmentKey(long[] packed, int hash) {
+        this.packed = packed;
+        this.hash = hash;
+    }
+
+    /**
+     * Pack current GLSM fragment state into pre-allocated output array.
+     * @param out must be at least MAX_UNITS (4) longs
+     * @return number of significant longs (1..4)
+     */
+    public static int packFromState(long[] out) {
+        long global = 0;
+
+        // Fog
+        if (GLStateManager.getFogMode().isEnabled()) {
+            final int fogMode = switch (GLStateManager.getFogState().getFogMode()) {
+                case GL11.GL_LINEAR -> FOG_LINEAR;
+                case GL11.GL_EXP    -> FOG_EXP;
+                case GL11.GL_EXP2   -> FOG_EXP2;
+                default -> FOG_NONE;
+            };
+            global |= (long) fogMode;
+        }
+
+        // Alpha test
+        if (GLStateManager.getAlphaTest().isEnabled()) {
+            global |= (1L << BIT_ALPHA_TEST);
+            global |= ((long) (encodeAlphaFunc(GLStateManager.getAlphaState().getFunction()) & 0x7)) << BIT_ALPHA_FUNC;
+        }
+
+        // Damage overlay
+        if (GLStateManager.getOverlayA() != 0.0f) {
+            global |= (1L << BIT_OVERLAY_ENABLED);
+        }
+
+        // Separate specular
+        if (GLStateManager.getLightingState().isEnabled()
+            && GLStateManager.getLightModel().colorControl == GL12.GL_SEPARATE_SPECULAR_COLOR) {
+            global |= (1L << BIT_SEPARATE_SPECULAR);
+        }
+
+        // Per-unit state
+        int highestEnabled = -1;
+        long unit0Bits = 0;
+        for (int i = 0; i < MAX_UNITS; i++) {
+            // Per Mesa - an enabled unit with no complete texture bound counts as disabled.
+            final boolean texEnabled = GLStateManager.getTextures().getTextureUnitStates(i).isEnabled() && GLStateManager.getTextures().getTextureUnitBindings(i).getBinding() != 0;
+            if (texEnabled) highestEnabled = i;
+
+            final long unitBits = packUnit(i, texEnabled);
+            if (i == 0) {
+                unit0Bits = unitBits;
+            } else {
+                out[i] = unitBits;
+            }
+        }
+
+        final int nrEnabled = highestEnabled + 1;
+        global |= ((long) (nrEnabled & 0x7)) << BIT_NR_ENABLED_UNITS;
+        global |= (unit0Bits << GLOBAL_BITS);
+        out[0] = global;
+
+        return Math.max(1, nrEnabled);
+    }
+
+    private static long packUnit(int unitIndex, boolean texEnabled) {
+        if (!texEnabled) return 0;
+
+        final TexEnvState envState = GLStateManager.getTextures().getTexEnvState(unitIndex);
+        final int mode = encodeTexEnvMode(envState.mode);
+
+        long bits = 1L; // enabled
+        bits |= ((long) (mode & 0x7)) << U_MODE;
+
+        boolean needsEnvColor = (mode == TEX_ENV_BLEND);
+
+        if (mode == TEX_ENV_COMBINE) {
+            final int combRgb = encodeCombineFunc(envState.combineRgb);
+            final int combAlpha = encodeCombineFunc(envState.combineAlpha);
+            bits |= ((long) (combRgb & 0xF)) << U_COMBINE_RGB;
+            bits |= ((long) (combAlpha & 0xF)) << U_COMBINE_ALPHA;
+            bits |= ((long) (encodeScale(envState.scaleRgb) & 0x3)) << U_SCALE_RGB;
+            bits |= ((long) (encodeScale(envState.scaleAlpha) & 0x3)) << U_SCALE_ALPHA;
+
+            // Only pack args actually used by each channel's combine function.
+            // Unused arg slots stay 0, preventing TexEnvState defaults from inflating the cache.
+            final int numArgsRgb = combineNumArgs(combRgb);
+            final int numArgsAlpha = combineNumArgs(combAlpha);
+            final int maxArgs = Math.max(numArgsRgb, numArgsAlpha);
+
+            for (int a = 0; a < maxArgs; a++) {
+                if (a < numArgsRgb) {
+                    final int srcR = encodeSource(envState.sourceRgb[a]);
+                    final int opR = encodeOperand(envState.operandRgb[a]);
+                    bits |= ((long) ((srcR & 0x7) | ((opR & 0x3) << 3))) << (U_ARG0_RGB + a * 5);
+                    if (srcR == SRC_CONSTANT) needsEnvColor = true;
+                }
+                if (a < numArgsAlpha) {
+                    final int srcA = encodeSource(envState.sourceAlpha[a]);
+                    final int opA = encodeOperand(envState.operandAlpha[a]);
+                    bits |= ((long) ((srcA & 0x7) | ((opA & 0x3) << 3))) << (U_ARG0_ALPHA + a * 5);
+                    if (srcA == SRC_CONSTANT) needsEnvColor = true;
+                }
+            }
+        }
+
+        if (needsEnvColor) {
+            bits |= (1L << U_NEEDS_ENV_COLOR);
+        }
+
+        return bits;
+    }
+
+    /** Create FragmentKey from packed scratch data. Only called on cache miss. */
+    public static FragmentKey fromPacked(long[] scratch, int len) {
+        final long[] copy = Arrays.copyOf(scratch, len);
+        return new FragmentKey(copy, Arrays.hashCode(copy));
+    }
+
+    /** Convenience: pack + create. Allocates. For infrequent paths. */
+    public static FragmentKey fromState() {
+        final long[] scratch = new long[MAX_UNITS];
+        final int len = packFromState(scratch);
+        return fromPacked(scratch, len);
+    }
+
+    @Override
+    public int hashCode() {
+        return hash;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (!(obj instanceof FragmentKey other)) return false;
+        if (hash != other.hash) return false;
+        return Arrays.equals(packed, other.packed);
+    }
+
+    public int fogMode()              { return (int) (packed[0] & 0x3); }
+    public boolean alphaTestEnabled() { return ((packed[0] >> BIT_ALPHA_TEST) & 1) != 0; }
+    public int alphaTestFunc()        { return (int) ((packed[0] >> BIT_ALPHA_FUNC) & 0x7); }
+    public boolean separateSpecular() { return ((packed[0] >> BIT_SEPARATE_SPECULAR) & 1) != 0; }
+    public int nrEnabledUnits()       { return (int) ((packed[0] >> BIT_NR_ENABLED_UNITS) & 0x7); }
+    public boolean overlayEnabled()   { return ((packed[0] >> BIT_OVERLAY_ENABLED) & 1) != 0; }
+
+    private long unitBits(int i) {
+        return (i == 0) ? (packed[0] >>> GLOBAL_BITS) : packed[i];
+    }
+
+    public boolean unitEnabled(int i)       { return (unitBits(i) & 1) != 0; }
+    public int unitMode(int i)              { return (int) ((unitBits(i) >> U_MODE) & 0x7); }
+    public boolean unitNeedsEnvColor(int i) { return ((unitBits(i) >> U_NEEDS_ENV_COLOR) & 1) != 0; }
+    public int unitCombineRgb(int i)        { return (int) ((unitBits(i) >> U_COMBINE_RGB) & 0xF); }
+    public int unitCombineAlpha(int i)      { return (int) ((unitBits(i) >> U_COMBINE_ALPHA) & 0xF); }
+    public int unitScaleShiftRgb(int i)     { return (int) ((unitBits(i) >> U_SCALE_RGB) & 0x3); }
+    public int unitScaleShiftAlpha(int i)   { return (int) ((unitBits(i) >> U_SCALE_ALPHA) & 0x3); }
+
+    public int unitSourceRgb(int i, int arg)    { return (int) ((unitBits(i) >> (U_ARG0_RGB + arg * 5)) & 0x7); }
+    public int unitOperandRgb(int i, int arg)   { return (int) ((unitBits(i) >> (U_ARG0_RGB + arg * 5 + 3)) & 0x3); }
+    public int unitSourceAlpha(int i, int arg)  { return (int) ((unitBits(i) >> (U_ARG0_ALPHA + arg * 5)) & 0x7); }
+    public int unitOperandAlpha(int i, int arg) { return (int) ((unitBits(i) >> (U_ARG0_ALPHA + arg * 5 + 3)) & 0x3); }
+
+    public boolean textureEnabled() {
+        for (int i = 0; i < nrEnabledUnits(); i++) {
+            if (unitEnabled(i)) return true;
+        }
+        return false;
+    }
+
+    /** Per-unit enable bits as a 4-bit mask (bit i = unit i enabled). */
+    public int enabledUnitMask() {
+        int mask = 0;
+        final int n = Math.min(nrEnabledUnits(), MAX_UNITS);
+        for (int i = 0; i < n; i++) {
+            if (unitEnabled(i)) mask |= (1 << i);
+        }
+        return mask;
+    }
+
+    /** Per-unit enable bits from a packed scratch as a 4-bit mask (bit i = unit i enabled). */
+    public static int unitMaskFromPacked(long[] packed, int len) {
+        int mask = 0;
+        if (len < 1) return 0;
+        if (((packed[0] >>> GLOBAL_BITS) & 1L) != 0) mask |= 1;
+        final int n = Math.min(len, MAX_UNITS);
+        for (int i = 1; i < n; i++) {
+            if ((packed[i] & 1L) != 0) mask |= (1 << i);
+        }
+        return mask;
+    }
+
+    public boolean lightmapEnabled() {
+        return nrEnabledUnits() > 1 && unitEnabled(1);
+    }
+
+    private static int encodeAlphaFunc(int glFunc) {
+        return glFunc & 0x7;
+    }
+
+    static int encodeTexEnvMode(int glMode) {
+        return switch (glMode) {
+            case GL11.GL_MODULATE -> TEX_ENV_MODULATE;
+            case GL11.GL_REPLACE  -> TEX_ENV_REPLACE;
+            case GL11.GL_ADD      -> TEX_ENV_ADD;
+            case GL11.GL_DECAL    -> TEX_ENV_DECAL;
+            case GL11.GL_BLEND    -> TEX_ENV_BLEND;
+            case GL13.GL_COMBINE -> TEX_ENV_COMBINE;
+            default -> TEX_ENV_MODULATE;
+        };
+    }
+
+    static int encodeCombineFunc(int glFunc) {
+        return switch (glFunc) {
+            case GL11.GL_REPLACE     -> COMBINE_REPLACE;
+            case GL11.GL_MODULATE    -> COMBINE_MODULATE;
+            case GL11.GL_ADD         -> COMBINE_ADD;
+            case GL13.GL_ADD_SIGNED  -> COMBINE_ADD_SIGNED;
+            case GL13.GL_INTERPOLATE -> COMBINE_INTERPOLATE;
+            case GL13.GL_SUBTRACT    -> COMBINE_SUBTRACT;
+            case GL13.GL_DOT3_RGB    -> COMBINE_DOT3_RGB;
+            case GL13.GL_DOT3_RGBA   -> COMBINE_DOT3_RGBA;
+            default -> COMBINE_REPLACE;
+        };
+    }
+
+    static int encodeSource(int glSource) {
+        return switch (glSource) {
+            case GL11.GL_TEXTURE       -> SRC_TEXTURE;
+            case GL13.GL_CONSTANT      -> SRC_CONSTANT;
+            case GL13.GL_PRIMARY_COLOR -> SRC_PRIMARY_COLOR;
+            case GL13.GL_PREVIOUS      -> SRC_PREVIOUS;
+            default -> {
+                GLStateManager.LOGGER.debug("Unknown TexEnv source 0x{}, falling back to SRC_PREVIOUS", Integer.toHexString(glSource));
+                yield SRC_PREVIOUS;
+            }
+        };
+    }
+
+    static int encodeOperand(int glOperand) {
+        return switch (glOperand) {
+            case GL11.GL_SRC_COLOR           -> OP_SRC_COLOR;
+            case GL11.GL_ONE_MINUS_SRC_COLOR -> OP_ONE_MINUS_SRC_COLOR;
+            case GL11.GL_SRC_ALPHA           -> OP_SRC_ALPHA;
+            case GL11.GL_ONE_MINUS_SRC_ALPHA -> OP_ONE_MINUS_SRC_ALPHA;
+            default -> OP_SRC_COLOR;
+        };
+    }
+
+    /** Number of source/operand args used by the given (encoded) combine function. */
+    public static int combineNumArgs(int func) {
+        return switch (func) {
+            case COMBINE_REPLACE -> 1;
+            case COMBINE_INTERPOLATE -> 3;
+            default -> 2; // MODULATE, ADD, ADD_SIGNED, SUBTRACT, DOT3_*
+        };
+    }
+
+    private static int encodeScale(float scale) {
+        if (scale >= 4.0f) return 2;
+        if (scale >= 2.0f) return 1;
+        return 0;
+    }
+
+    public static int decodeAlphaFunc(int encoded) {
+        return 0x0200 | encoded;
+    }
+
+    @Override
+    public String toString() {
+        final String fogName = switch (fogMode()) {
+            case FOG_NONE   -> "NONE";
+            case FOG_LINEAR -> "LINEAR";
+            case FOG_EXP    -> "EXP";
+            case FOG_EXP2   -> "EXP2";
+            default -> "?";
+        };
+        final StringBuilder sb = new StringBuilder();
+        sb.append(String.format("FFPFragmentKey[fog=%s alpha=%b(%s) specSep=%b overlay=%b units=%d",
+            fogName, alphaTestEnabled(),
+            alphaTestEnabled() ? String.format("0x%04X", decodeAlphaFunc(alphaTestFunc())) : "-",
+            separateSpecular(), overlayEnabled(), nrEnabledUnits()));
+        for (int i = 0; i < nrEnabledUnits(); i++) {
+            if (!unitEnabled(i)) {
+                sb.append(String.format(" u%d=OFF", i));
+            } else {
+                final String modeName = switch (unitMode(i)) {
+                    case TEX_ENV_MODULATE -> "MOD";
+                    case TEX_ENV_REPLACE  -> "REPL";
+                    case TEX_ENV_ADD      -> "ADD";
+                    case TEX_ENV_DECAL    -> "DEC";
+                    case TEX_ENV_BLEND    -> "BL";
+                    case TEX_ENV_COMBINE  -> "COMB";
+                    default -> "?";
+                };
+                sb.append(String.format(" u%d=%s", i, modeName));
+            }
+        }
+        sb.append(']');
+        return sb.toString();
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/FragmentShaderGenerator.java

@@ -0,0 +1,338 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import org.lwjgl.opengl.GL11;
+
+/**
+ * Generates GLSL 330 core fragment shaders for FFP emulation.
+ * Supports per-unit texenv chain including GL_COMBINE mode.
+ * Follows Mesa's ff_fragment_shader.c and st_nir_lower_fog.c.
+ */
+public final class FragmentShaderGenerator {
+
+    private FragmentShaderGenerator() {}
+
+    public static String generate(FragmentKey key) {
+        final StringBuilder sb = new StringBuilder(2048);
+        sb.append("#version 330 core\n\n");
+
+        emitInputs(sb, key);
+        emitUniforms(sb, key);
+        sb.append("out vec4 fragColor;\n\n");
+
+        sb.append("void main() {\n");
+        emitTextureSampling(sb, key);
+        emitTexEnvChain(sb, key);
+        emitSpecularAdd(sb, key);
+        emitAlphaTest(sb, key);
+        emitFog(sb, key);
+        sb.append("  fragColor = color;\n");
+        sb.append("}\n");
+
+        return sb.toString();
+    }
+
+    private static void emitInputs(StringBuilder sb, FragmentKey key) {
+        sb.append("// Inputs from vertex shader\n");
+        sb.append("in vec4 v_Color;\n");
+        if (key.separateSpecular()) {
+            sb.append("in vec3 v_SpecularColor;\n");
+        }
+        // Per-unit texcoord inputs. Each enabled unit sources from its own varying
+        for (int i = 0; i < key.nrEnabledUnits(); i++) {
+            if (key.unitEnabled(i)) {
+                sb.append("in vec4 v_TexCoord").append(i).append(";\n");
+            }
+        }
+        if (key.fogMode() != FragmentKey.FOG_NONE) {
+            sb.append("in float v_FogCoord;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitUniforms(StringBuilder sb, FragmentKey key) {
+        // Samplers for each enabled unit
+        for (int i = 0; i < key.nrEnabledUnits(); i++) {
+            if (key.unitEnabled(i)) {
+                sb.append("uniform sampler2D u_Sampler").append(i).append(";\n");
+            }
+        }
+        if (key.alphaTestEnabled()) {
+            sb.append("uniform float u_AlphaRef;\n");
+        }
+        // Per-unit texEnvColor uniforms
+        for (int i = 0; i < key.nrEnabledUnits(); i++) {
+            if (key.unitEnabled(i) && key.unitNeedsEnvColor(i)) {
+                sb.append("uniform vec4 u_TexEnvColor").append(i).append(";\n");
+            }
+        }
+        if (key.overlayEnabled()) {
+            sb.append("uniform vec4 u_OverlayColor;\n");
+        }
+        if (key.fogMode() != FragmentKey.FOG_NONE) {
+            sb.append("uniform vec4 u_FogParams;\n");
+            sb.append("uniform vec4 u_FogColor;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitTextureSampling(StringBuilder sb, FragmentKey key) {
+        for (int i = 0; i < key.nrEnabledUnits(); i++) {
+            if (!key.unitEnabled(i)) continue;
+            sb.append("  vec4 tex").append(i).append("Color = textureProj(u_Sampler").append(i).append(", v_TexCoord").append(i).append(");\n");
+        }
+    }
+
+    private static void emitTexEnvChain(StringBuilder sb, FragmentKey key) {
+        if (!key.textureEnabled()) {
+            sb.append("  // No texture -- vertex color only\n");
+            sb.append("  vec4 color = v_Color;\n");
+            emitOverlay(sb, key);
+            return;
+        }
+
+        // Process units in order; "previous" starts as vertex color.
+        boolean firstUnit = true;
+        boolean overlayInjected = false;
+        for (int i = 0; i < key.nrEnabledUnits(); i++) {
+            if (!key.unitEnabled(i)) continue;
+
+            if (!firstUnit && !overlayInjected) {
+                emitOverlay(sb, key);
+                overlayInjected = true;
+            }
+
+            final String texVar = "tex" + i + "Color";
+            final String envColorVar = "u_TexEnvColor" + i;
+            final String prevVar = firstUnit ? "v_Color" : "color";
+            final String assign = firstUnit ? "  vec4 color = " : "  color = ";
+
+            if (key.unitMode(i) == FragmentKey.TEX_ENV_COMBINE) {
+                emitCombineUnit(sb, key, i, texVar, envColorVar, prevVar, assign);
+            } else {
+                emitSimpleUnit(sb, key, i, texVar, envColorVar, prevVar, assign);
+            }
+            firstUnit = false;
+        }
+
+        if (!overlayInjected) emitOverlay(sb, key);
+    }
+
+    /**
+     * Emit the modern-style damage overlay mix.
+     */
+    private static void emitOverlay(StringBuilder sb, FragmentKey key) {
+        if (!key.overlayEnabled()) return;
+        sb.append("  color.rgb = mix(color.rgb, u_OverlayColor.rgb, u_OverlayColor.a);\n");
+    }
+
+    private static void emitSimpleUnit(StringBuilder sb, FragmentKey key, int unit, String texVar, String envColorVar, String prevVar, String assign) {
+        switch (key.unitMode(unit)) {
+            case FragmentKey.TEX_ENV_REPLACE -> {
+                sb.append("  // Unit ").append(unit).append(" (REPLACE)\n");
+                sb.append(assign).append(texVar).append(";\n");
+            }
+            case FragmentKey.TEX_ENV_ADD -> {
+                sb.append("  // Unit ").append(unit).append(" (ADD)\n");
+                sb.append(assign).append("vec4(clamp(").append(prevVar).append(".rgb + ").append(texVar).append(".rgb, 0.0, 1.0), ")
+                    .append(prevVar).append(".a * ").append(texVar).append(".a);\n");
+            }
+            case FragmentKey.TEX_ENV_DECAL -> {
+                sb.append("  // Unit ").append(unit).append(" (DECAL)\n");
+                sb.append(assign).append("vec4(mix(").append(prevVar).append(".rgb, ").append(texVar).append(".rgb, ").append(texVar).append(".a), ")
+                    .append(prevVar).append(".a);\n");
+            }
+            case FragmentKey.TEX_ENV_BLEND -> {
+                sb.append("  // Unit ").append(unit).append(" (BLEND)\n");
+                sb.append(assign).append("vec4(").append(prevVar).append(".rgb * (vec3(1.0) - ").append(texVar).append(".rgb) + ")
+                    .append(envColorVar).append(".rgb * ").append(texVar).append(".rgb, ")
+                    .append(prevVar).append(".a * ").append(texVar).append(".a);\n");
+            }
+            default -> { // MODULATE
+                sb.append("  // Unit ").append(unit).append(" (MODULATE)\n");
+                sb.append(assign).append(prevVar).append(" * ").append(texVar).append(";\n");
+            }
+        }
+    }
+
+    /** Emit a GL_COMBINE texenv unit */
+    private static void emitCombineUnit(StringBuilder sb, FragmentKey key, int unit, String texVar, String envColorVar, String prevVar, String assign) {
+        sb.append("  // Unit ").append(unit).append(" (COMBINE)\n");
+
+        final String rgbResult = "combRgb" + unit;
+        final String alphaResult = "combAlpha" + unit;
+
+        if (key.unitCombineRgb(unit) == FragmentKey.COMBINE_DOT3_RGBA) {
+            sb.append("  vec3 ").append(rgbResult).append(";\n");
+            sb.append("  {\n");
+            emitCombineChannel(sb, key, unit, texVar, envColorVar, prevVar, true);
+            sb.append("  }\n");
+            sb.append(assign).append("vec4(").append(rgbResult).append(", ").append(rgbResult).append(".x);\n");
+        } else {
+            sb.append("  vec3 ").append(rgbResult).append(";\n");
+            sb.append("  float ").append(alphaResult).append(";\n");
+            sb.append("  {\n");
+            emitCombineChannel(sb, key, unit, texVar, envColorVar, prevVar, true);
+            emitCombineChannel(sb, key, unit, texVar, envColorVar, prevVar, false);
+            sb.append("  }\n");
+            sb.append(assign).append("vec4(").append(rgbResult).append(", ").append(alphaResult).append(");\n");
+        }
+    }
+
+    /**
+     * Emit one channel (RGB or Alpha) of a GL_COMBINE unit.
+     */
+    private static void emitCombineChannel(StringBuilder sb, FragmentKey key, int unit, String texVar, String envColorVar, String prevVar, boolean isRgb) {
+        final String suffix = isRgb ? "Rgb" : "Alpha";
+        final String type = isRgb ? "vec3" : "float";
+        final int combineFunc = isRgb ? key.unitCombineRgb(unit) : key.unitCombineAlpha(unit);
+        final int scaleShift = isRgb ? key.unitScaleShiftRgb(unit) : key.unitScaleShiftAlpha(unit);
+
+        // Guard: DOT3 is invalid for alpha channel — fallback to REPLACE
+        final int effectiveFunc;
+        if (!isRgb && (combineFunc == FragmentKey.COMBINE_DOT3_RGB || combineFunc == FragmentKey.COMBINE_DOT3_RGBA)) {
+            effectiveFunc = FragmentKey.COMBINE_REPLACE;
+        } else {
+            effectiveFunc = combineFunc;
+        }
+
+        // Determine how many args we need
+        final int numArgs = combineNumArgs(effectiveFunc);
+
+        // Emit argument resolution
+        for (int a = 0; a < numArgs; a++) {
+            final int source = isRgb ? key.unitSourceRgb(unit, a) : key.unitSourceAlpha(unit, a);
+            final int operand = isRgb ? key.unitOperandRgb(unit, a) : key.unitOperandAlpha(unit, a);
+            final String argName = "arg" + suffix + a + "_" + unit;
+            final String sourceExpr = resolveSource(source, texVar, envColorVar, prevVar);
+            final String operandExpr = applyOperand(sourceExpr, operand, isRgb);
+            sb.append("    ").append(type).append(" ").append(argName).append(" = ").append(operandExpr).append(";\n");
+        }
+
+        // Emit combine operation
+        final String resultName = "comb" + suffix + unit;
+        final String a0 = "arg" + suffix + "0_" + unit;
+        final String a1 = "arg" + suffix + "1_" + unit;
+        final String a2 = "arg" + suffix + "2_" + unit;
+
+        sb.append("    ").append(resultName).append(" = ");
+        switch (effectiveFunc) {
+            case FragmentKey.COMBINE_REPLACE -> sb.append(a0);
+            case FragmentKey.COMBINE_MODULATE -> sb.append(a0).append(" * ").append(a1);
+            case FragmentKey.COMBINE_ADD -> sb.append(a0).append(" + ").append(a1);
+            case FragmentKey.COMBINE_ADD_SIGNED ->
+                sb.append(a0).append(" + ").append(a1).append(" - ").append(isRgb ? "vec3(0.5)" : "0.5");
+            case FragmentKey.COMBINE_SUBTRACT -> sb.append(a0).append(" - ").append(a1);
+            case FragmentKey.COMBINE_INTERPOLATE ->
+                sb.append("mix(").append(a1).append(", ").append(a0).append(", ").append(a2).append(")");
+            case FragmentKey.COMBINE_DOT3_RGB, FragmentKey.COMBINE_DOT3_RGBA ->
+                sb.append("vec3(4.0 * dot(").append(a0).append(" - vec3(0.5), ").append(a1).append(" - vec3(0.5)))");
+            default -> sb.append(a0); // fallback to REPLACE
+        }
+        sb.append(";\n");
+
+        // Apply scale
+        if (scaleShift > 0) {
+            final String scaleFactor = scaleShift == 1 ? "2.0" : "4.0";
+            sb.append("    ").append(resultName).append(" *= ").append(scaleFactor).append(";\n");
+        }
+
+        // Clamp
+        sb.append("    ").append(resultName).append(" = clamp(").append(resultName).append(", ")
+            .append(isRgb ? "vec3(0.0), vec3(1.0)" : "0.0, 1.0").append(");\n");
+    }
+
+    private static String resolveSource(int source, String texVar, String envColorVar, String prevVar) {
+        return switch (source) {
+            case FragmentKey.SRC_TEXTURE -> texVar;
+            case FragmentKey.SRC_CONSTANT -> envColorVar;
+            case FragmentKey.SRC_PRIMARY_COLOR -> "v_Color";
+            case FragmentKey.SRC_PREVIOUS -> prevVar;
+            default -> prevVar;
+        };
+    }
+
+    private static String applyOperand(String sourceExpr, int operand, boolean isRgb) {
+        if (isRgb) {
+            return switch (operand) {
+                case FragmentKey.OP_SRC_COLOR -> sourceExpr + ".rgb";
+                case FragmentKey.OP_ONE_MINUS_SRC_COLOR -> "(vec3(1.0) - " + sourceExpr + ".rgb)";
+                case FragmentKey.OP_SRC_ALPHA -> "vec3(" + sourceExpr + ".a)";
+                case FragmentKey.OP_ONE_MINUS_SRC_ALPHA -> "vec3(1.0 - " + sourceExpr + ".a)";
+                default -> sourceExpr + ".rgb";
+            };
+        } else {
+            return switch (operand) {
+                case FragmentKey.OP_SRC_ALPHA -> sourceExpr + ".a";
+                case FragmentKey.OP_ONE_MINUS_SRC_ALPHA -> "(1.0 - " + sourceExpr + ".a)";
+                // Per GL spec, alpha channel operands are SRC_ALPHA or ONE_MINUS_SRC_ALPHA only, but handle color operands gracefully
+                case FragmentKey.OP_SRC_COLOR -> sourceExpr + ".a";
+                case FragmentKey.OP_ONE_MINUS_SRC_COLOR -> "(1.0 - " + sourceExpr + ".a)";
+                default -> sourceExpr + ".a";
+            };
+        }
+    }
+
+    private static int combineNumArgs(int func) {
+        return FragmentKey.combineNumArgs(func);
+    }
+
+    private static void emitSpecularAdd(StringBuilder sb, FragmentKey key) {
+        if (key.separateSpecular()) {
+            sb.append("  // Add separate specular\n");
+            sb.append("  color.rgb += v_SpecularColor;\n");
+        }
+    }
+
+    private static void emitAlphaTest(StringBuilder sb, FragmentKey key) {
+        if (!key.alphaTestEnabled()) return;
+
+        sb.append("  // Alpha test\n");
+        final int func = FragmentKey.decodeAlphaFunc(key.alphaTestFunc());
+
+
+        sb.append("  float qa = round(color.a * 255.0);\n");
+        switch (func) {
+            case GL11.GL_NEVER ->
+                sb.append("  discard;\n");
+            case GL11.GL_LESS ->
+                sb.append("  if (qa >= u_AlphaRef * 255.0) discard;\n");
+            case GL11.GL_EQUAL -> {
+                sb.append("  float qr = round(u_AlphaRef * 255.0);\n");
+                sb.append("  if (qa != qr) discard;\n");
+            }
+            case GL11.GL_LEQUAL ->
+                sb.append("  if (qa > u_AlphaRef * 255.0) discard;\n");
+            case GL11.GL_GREATER ->
+                sb.append("  if (qa <= u_AlphaRef * 255.0) discard;\n");
+            case GL11.GL_NOTEQUAL -> {
+                sb.append("  float qr = round(u_AlphaRef * 255.0);\n");
+                sb.append("  if (qa == qr) discard;\n");
+            }
+            case GL11.GL_GEQUAL ->
+                sb.append("  if (qa < u_AlphaRef * 255.0) discard;\n");
+            case GL11.GL_ALWAYS -> {}
+        }
+    }
+
+    private static void emitFog(StringBuilder sb, FragmentKey key) {
+        final int fogMode = key.fogMode();
+        if (fogMode == FragmentKey.FOG_NONE) return;
+
+        sb.append("  // Fog\n");
+        sb.append("  float f;\n");
+
+        switch (fogMode) {
+            case FragmentKey.FOG_LINEAR ->
+                sb.append("  f = v_FogCoord * u_FogParams.x + u_FogParams.y;\n");
+            case FragmentKey.FOG_EXP ->
+                sb.append("  f = exp2(-(v_FogCoord * u_FogParams.z));\n");
+            case FragmentKey.FOG_EXP2 -> {
+                sb.append("  float fogTmp = v_FogCoord * u_FogParams.w;\n");
+                sb.append("  f = exp2(-(fogTmp * fogTmp));\n");
+            }
+        }
+
+        sb.append("  f = clamp(f, 0.0, 1.0);\n");
+        sb.append("  color.rgb = mix(u_FogColor.rgb, color.rgb, f);\n");
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/GeometryShaderGenerator.java

@@ -0,0 +1,98 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+/**
+ * Generates GLSL 330 core geometry shaders for wide line emulation.
+ */
+public final class GeometryShaderGenerator {
+
+    private GeometryShaderGenerator() {}
+
+    public static String generate(VertexKey key) {
+        final StringBuilder sb = new StringBuilder(1024);
+        sb.append("#version 330 core\n\n");
+
+        sb.append("layout(lines) in;\n");
+        sb.append("layout(triangle_strip, max_vertices = 4) out;\n\n");
+
+        sb.append("uniform vec2 u_ViewportSize;\n");
+        sb.append("uniform float u_LineWidth;\n\n");
+
+        sb.append("// Pass-through varyings\n");
+        sb.append("in vec4 v_Color_gs[];\n");
+        if (key.separateSpecular()) {
+            sb.append("in vec3 v_SpecularColor_gs[];\n");
+        }
+        if (key.unitTexCoordEnabled(0) || key.texGenEnabled()) sb.append("in vec4 v_TexCoord0_gs[];\n");
+        if (key.lightmapEnabled())            sb.append("in vec4 v_TexCoord1_gs[];\n");
+        if (key.unitTexCoordEnabled(2))       sb.append("in vec4 v_TexCoord2_gs[];\n");
+        if (key.unitTexCoordEnabled(3))       sb.append("in vec4 v_TexCoord3_gs[];\n");
+        if (key.fogEnabled()) {
+            sb.append("in float v_FogCoord_gs[];\n");
+        }
+        sb.append('\n');
+
+        sb.append("out vec4 v_Color;\n");
+        if (key.separateSpecular()) {
+            sb.append("out vec3 v_SpecularColor;\n");
+        }
+        if (key.unitTexCoordEnabled(0) || key.texGenEnabled()) sb.append("out vec4 v_TexCoord0;\n");
+        if (key.lightmapEnabled())            sb.append("out vec4 v_TexCoord1;\n");
+        if (key.unitTexCoordEnabled(2))       sb.append("out vec4 v_TexCoord2;\n");
+        if (key.unitTexCoordEnabled(3))       sb.append("out vec4 v_TexCoord3;\n");
+        if (key.fogEnabled()) {
+            sb.append("out float v_FogCoord;\n");
+        }
+        sb.append('\n');
+
+        sb.append("void main() {\n");
+        sb.append("    vec4 c0 = gl_in[0].gl_Position;\n");
+        sb.append("    vec4 c1 = gl_in[1].gl_Position;\n\n");
+
+        sb.append("    // NDC positions\n");
+        sb.append("    vec2 n0 = c0.xy / c0.w;\n");
+        sb.append("    vec2 n1 = c1.xy / c1.w;\n\n");
+
+        sb.append("    // Screen-space direction and perpendicular\n");
+        sb.append("    vec2 dir = normalize((n1 - n0) * u_ViewportSize);\n");
+        sb.append("    vec2 offset = vec2(-dir.y, dir.x) * u_LineWidth / u_ViewportSize;\n\n");
+
+        emitVertex(sb, key, 0, "+offset");
+        emitVertex(sb, key, 0, "-offset");
+        emitVertex(sb, key, 1, "+offset");
+        emitVertex(sb, key, 1, "-offset");
+
+        sb.append("    EndPrimitive();\n");
+        sb.append("}\n");
+
+        return sb.toString();
+    }
+
+    private static void emitVertex(StringBuilder sb, VertexKey key, int endpointIdx, String offsetExpr) {
+        final String ci = "c" + endpointIdx;
+        final String ni = "n" + endpointIdx;
+        final String idx = "[" + endpointIdx + "]";
+
+        sb.append("    // Endpoint ").append(endpointIdx).append(' ').append(offsetExpr).append('\n');
+
+        sb.append("    v_Color = v_Color_gs").append(idx).append(";\n");
+        if (key.separateSpecular()) {
+            sb.append("    v_SpecularColor = v_SpecularColor_gs").append(idx).append(";\n");
+        }
+        if (key.unitTexCoordEnabled(0) || key.texGenEnabled()) sb.append("    v_TexCoord0 = v_TexCoord0_gs").append(idx).append(";\n");
+        if (key.lightmapEnabled())            sb.append("    v_TexCoord1 = v_TexCoord1_gs").append(idx).append(";\n");
+        if (key.unitTexCoordEnabled(2))       sb.append("    v_TexCoord2 = v_TexCoord2_gs").append(idx).append(";\n");
+        if (key.unitTexCoordEnabled(3))       sb.append("    v_TexCoord3 = v_TexCoord3_gs").append(idx).append(";\n");
+        if (key.fogEnabled()) {
+            sb.append("    v_FogCoord = v_FogCoord_gs").append(idx).append(";\n");
+        }
+
+        if (key.clipPlanesEnabled()) {
+            for (int i = 0; i < 8; i++) {
+                sb.append("    gl_ClipDistance[").append(i).append("] = gl_in").append(idx).append(".gl_ClipDistance[").append(i).append("];\n");
+            }
+        }
+
+        sb.append("    gl_Position = vec4((").append(ni).append(' ').append(offsetExpr).append(") * ").append(ci).append(".w, ").append(ci).append(".z, ").append(ci).append(".w);\n");
+        sb.append("    EmitVertex();\n\n");
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/Program.java

@@ -0,0 +1,288 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizons.angelica.glsm.GLDebug;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.backend.RenderBackend;
+import lombok.Getter;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL20;
+import org.lwjgl.opengl.GL32;
+import org.lwjgl.opengl.GL40;
+import org.lwjgl.opengl.GL43;
+import org.lwjgl.opengl.KHRDebug;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * A compiled and linked FFP emulation program (vertex + fragment + optional geometry shaders). Owns the GL program handle and caches uniform locations.
+ */
+public class Program {
+
+    private static final AtomicInteger PROGRAM_COUNTER = new AtomicInteger();
+
+    @Getter private final int programId;
+    @Getter private final VertexKey vertexKey;
+    @Getter private final FragmentKey fragmentKey;
+
+    // Per-program uniform dirty-tracking
+    static final class UploadState {
+        int mvGen = -1, mvLinearGen = -1, projGen = -1, texMatGen = -1;
+        int lightingGen = -1, fragmentGen = -1, colorGen = -1, normalGen = -1, texCoordGen = -1;
+        int texGenGen = -1, clipPlaneGen = -1;
+        float lightmapX = Float.NaN, lightmapY = Float.NaN, lineWidth = Float.NaN;
+        int viewportWidth = -1, viewportHeight = -1;
+    }
+    final UploadState uploadState = new UploadState();
+
+    // Uniform locations (-1 = not present in this variant)
+    // Matrices
+    public int locModelViewMatrix = -1;
+    public int locProjectionMatrix = -1;
+    public int locMVPMatrix = -1;
+    public int locNormalMatrix = -1;
+    public final int[] locTextureMatrix = { -1, -1, -1, -1 };
+
+    // Current state defaults
+    public int locCurrentNormal = -1;
+    public int locCurrentColor = -1;
+    public final int[] locCurrentTexCoord = { -1, -1, -1, -1 };
+    public int locCurrentLightmapCoord = -1;
+    public int locLightmapTextureMatrix = -1;
+
+    // Lighting - color material path (raw values)
+    public int locLightModelAmbient = -1;
+    public int locMaterialEmission = -1;
+    public int locMaterialAmbient = -1;
+    public int locMaterialDiffuse = -1;
+    public int locMaterialSpecular = -1;
+    public int locMaterialShininess = -1;
+    public int locLight0Ambient = -1;
+    public int locLight0Diffuse = -1;
+    public int locLight0Specular = -1;
+    public int locLight1Ambient = -1;
+    public int locLight1Diffuse = -1;
+    public int locLight1Specular = -1;
+
+    // Lighting - pre-computed path
+    public int locSceneColor = -1;
+    public int locLightProd0Ambient = -1;
+    public int locLightProd0Diffuse = -1;
+    public int locLightProd0Specular = -1;
+    public int locLightProd1Ambient = -1;
+    public int locLightProd1Diffuse = -1;
+    public int locLightProd1Specular = -1;
+
+    // Light positions
+    public int locLight0Position = -1;
+    public int locLight1Position = -1;
+
+    // Normal scale (for rescale normals)
+    public int locNormalScale = -1;
+
+    // TexGen plane uniforms
+    public int locTexGenObjPlaneS = -1;
+    public int locTexGenObjPlaneT = -1;
+    public int locTexGenObjPlaneR = -1;
+    public int locTexGenObjPlaneQ = -1;
+    public int locTexGenEyePlaneS = -1;
+    public int locTexGenEyePlaneT = -1;
+    public int locTexGenEyePlaneR = -1;
+    public int locTexGenEyePlaneQ = -1;
+
+    // Clip planes
+    public int locClipPlanes = -1;
+
+    // Wide line emulation (geometry shader)
+    public int locViewportSize = -1;
+    public int locLineWidth = -1;
+
+    // Fragment uniforms
+    public final int[] locSampler = { -1, -1, -1, -1 };
+    public int locAlphaRef = -1;
+    public final int[] locTexEnvColor = { -1, -1, -1, -1 };
+    public int locOverlayColor = -1;
+    public int locFogParams = -1;
+    public int locFogColor = -1;
+
+    Program(int programId, VertexKey vertexKey, FragmentKey fragmentKey) {
+        this.programId = programId;
+        this.vertexKey = vertexKey;
+        this.fragmentKey = fragmentKey;
+        resolveLocations();
+    }
+
+    private void resolveLocations() {
+        locModelViewMatrix = loc("u_ModelViewMatrix");
+        locProjectionMatrix = loc("u_ProjectionMatrix");
+        locMVPMatrix = loc("u_MVPMatrix");
+        locNormalMatrix = loc("u_NormalMatrix");
+        for (int i = 0; i < 4; i++) {
+            locTextureMatrix[i] = loc("u_TextureMatrix" + i);
+            locCurrentTexCoord[i] = loc("u_CurrentTexCoord" + i);
+        }
+
+        locCurrentNormal = loc("u_CurrentNormal");
+        locCurrentColor = loc("u_CurrentColor");
+        locCurrentLightmapCoord = loc("u_CurrentLightmapCoord");
+        locLightmapTextureMatrix = loc("u_LightmapTextureMatrix");
+
+        // Color material path
+        locLightModelAmbient = loc("u_LightModelAmbient");
+        locMaterialEmission = loc("u_MaterialEmission");
+        locMaterialAmbient = loc("u_MaterialAmbient");
+        locMaterialDiffuse = loc("u_MaterialDiffuse");
+        locMaterialSpecular = loc("u_MaterialSpecular");
+        locMaterialShininess = loc("u_MaterialShininess");
+        locLight0Ambient = loc("u_Light0Ambient");
+        locLight0Diffuse = loc("u_Light0Diffuse");
+        locLight0Specular = loc("u_Light0Specular");
+        locLight1Ambient = loc("u_Light1Ambient");
+        locLight1Diffuse = loc("u_Light1Diffuse");
+        locLight1Specular = loc("u_Light1Specular");
+
+        // Pre-computed path
+        locSceneColor = loc("u_SceneColor");
+        locLightProd0Ambient = loc("u_LightProd0Ambient");
+        locLightProd0Diffuse = loc("u_LightProd0Diffuse");
+        locLightProd0Specular = loc("u_LightProd0Specular");
+        locLightProd1Ambient = loc("u_LightProd1Ambient");
+        locLightProd1Diffuse = loc("u_LightProd1Diffuse");
+        locLightProd1Specular = loc("u_LightProd1Specular");
+
+        // Light positions
+        locLight0Position = loc("u_Light0Position");
+        locLight1Position = loc("u_Light1Position");
+
+        locNormalScale = loc("u_NormalScale");
+
+        // TexGen
+        locTexGenObjPlaneS = loc("u_TexGenObjPlaneS");
+        locTexGenObjPlaneT = loc("u_TexGenObjPlaneT");
+        locTexGenObjPlaneR = loc("u_TexGenObjPlaneR");
+        locTexGenObjPlaneQ = loc("u_TexGenObjPlaneQ");
+        locTexGenEyePlaneS = loc("u_TexGenEyePlaneS");
+        locTexGenEyePlaneT = loc("u_TexGenEyePlaneT");
+        locTexGenEyePlaneR = loc("u_TexGenEyePlaneR");
+        locTexGenEyePlaneQ = loc("u_TexGenEyePlaneQ");
+
+        // Clip planes
+        locClipPlanes = loc("u_ClipPlane[0]");
+
+        // Wide line emulation
+        locViewportSize = loc("u_ViewportSize");
+        locLineWidth = loc("u_LineWidth");
+
+        // Fragment
+        for (int i = 0; i < 4; i++) {
+            locSampler[i] = loc("u_Sampler" + i);
+        }
+        locAlphaRef = loc("u_AlphaRef");
+        for (int i = 0; i < 4; i++) {
+            locTexEnvColor[i] = loc("u_TexEnvColor" + i);
+        }
+        locOverlayColor = loc("u_OverlayColor");
+        locFogParams = loc("u_FogParams");
+        locFogColor = loc("u_FogColor");
+    }
+
+    private int loc(String name) {
+        return RENDER_BACKEND.getUniformLocation(programId, name);
+    }
+
+    public void destroy() {
+        GLStateManager.glDeleteProgram(programId);
+    }
+
+    /**
+     * Compile vertex + fragment + optional geometry shaders, link into a program, and return the FFPProgram.
+     */
+    static Program create(VertexKey vk, FragmentKey fk, String vertSrc, String fragSrc, String geomSrc) {
+        final RenderBackend backend = RENDER_BACKEND;
+        final int id = PROGRAM_COUNTER.getAndIncrement();
+        final String vkHex = Long.toHexString(vk.pack());
+        final boolean hasGeom = geomSrc != null;
+
+        int shaderCount = 0;
+        final int[] shaders = new int[5]; // vertex, fragment, geometry, tess control, tess evaluation
+        int program = 0;
+        try {
+            shaders[shaderCount++] = compileShader(GL20.GL_VERTEX_SHADER, vertSrc, "ffp_v_" + vkHex);
+            shaders[shaderCount++] = compileShader(GL20.GL_FRAGMENT_SHADER, fragSrc, "ffp_f_" + id);
+            if (geomSrc != null) {
+                shaders[shaderCount++] = compileShader(GL32.GL_GEOMETRY_SHADER, geomSrc, "ffp_g_" + id);
+            }
+
+            program = backend.createProgram();
+            for (int i = 0; i < shaderCount; i++) backend.attachShader(program, shaders[i]);
+            backend.linkProgram(program);
+
+            final String log = backend.getProgramInfoLog(program, backend.getProgrami(program, GL20.GL_INFO_LOG_LENGTH));
+            if (!log.isEmpty()) {
+                GLStateManager.LOGGER.warn("FFP program link log (vk=0x{}, fk={}): {}", vkHex, fk, log);
+            }
+
+            if (backend.getProgrami(program, GL20.GL_LINK_STATUS) != GL11.GL_TRUE) {
+                throw new RuntimeException("FFP shader link failed (vk=0x" + vkHex + ", fk=" + fk + "): " + log);
+            }
+
+            final String debugName = "FFP(v=0x" + vkHex + ",f=" + id + (hasGeom ? ",g" : "") + ")";
+            GLDebug.nameObject(KHRDebug.GL_PROGRAM, program, debugName);
+
+            // Detach and delete individual shaders — they're linked into the program
+            for (int i = 0; i < shaderCount; i++) {
+                backend.detachShader(program, shaders[i]);
+                backend.deleteShader(shaders[i]);
+            }
+            shaderCount = 0;
+
+            final Program ffpProgram = new Program(program, vk, fk);
+
+            final int previousProgram = GLStateManager.getActiveProgram();
+            backend.useProgram(program);
+            for (int i = 0; i < 4; i++) {
+                if (ffpProgram.locSampler[i] != -1) backend.uniform1i(ffpProgram.locSampler[i], i);
+            }
+            backend.useProgram(previousProgram);
+
+            return ffpProgram;
+        } catch (RuntimeException e) {
+            if (program != 0) backend.deleteProgram(program);
+            for (int i = 0; i < shaderCount; i++) backend.deleteShader(shaders[i]);
+            throw e;
+        }
+    }
+
+    private static int compileShader(int type, String src, String name) {
+        final RenderBackend backend = RENDER_BACKEND;
+        final int shader = backend.createShader(type);
+        backend.shaderSource(shader, src);
+        backend.compileShader(shader);
+
+        final String typeName = switch (type) {
+            case GL20.GL_VERTEX_SHADER -> "vertex";
+            case GL20.GL_FRAGMENT_SHADER -> "fragment";
+            case GL32.GL_GEOMETRY_SHADER -> "geometry";
+            case GL40.GL_TESS_CONTROL_SHADER -> "tess_control";
+            case GL40.GL_TESS_EVALUATION_SHADER -> "tess_evaluation";
+            case GL43.GL_COMPUTE_SHADER -> "compute";
+            default -> "unknown(0x" + Integer.toHexString(type) + ")";
+        };
+        GLDebug.nameObject(KHRDebug.GL_SHADER, shader, name + "(" + typeName + ")");
+
+        final String log = backend.getShaderInfoLog(shader, backend.getShaderi(shader, GL20.GL_INFO_LOG_LENGTH));
+        if (!log.isEmpty()) {
+            GLStateManager.LOGGER.warn("FFP {} shader compilation log for {}: {}", typeName, name, log);
+        }
+
+        final int result = backend.getShaderi(shader, GL20.GL_COMPILE_STATUS);
+        if (result != GL11.GL_TRUE) {
+            GLStateManager.LOGGER.error("FFP {} shader source:\n{}", typeName, src);
+            backend.deleteShader(shader);
+            throw new RuntimeException("FFP " + typeName + " shader compilation failed for " + name + ": " + log);
+        }
+
+        return shader;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/ShaderCache.java

@@ -0,0 +1,294 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
+import lombok.Setter;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.IdentityHashMap;
+
+
+/**
+ * Open-addressed cache for FFP shader program variants.
+ * Keyed on (vertexKey, fragmentKey) pairs stored inline as raw longs — zero allocation on cache hits.
+ * Converges on Mesa's prog_cache.c: hash+memcmp over packed bytes, open addressing.
+ *
+ * <p>Layout per slot in {@code keys[]}: {@link #SLOT_STRIDE}=6 longs
+ * <pre>
+ *   [0]: vertexKeyPacked
+ *   [1]: (fkLen &lt;&lt; 48) | (hash &amp; 0x0000_FFFF_FFFF_FFFF)  — never 0 for valid entries (fkLen &gt;= 1)
+ *   [2..5]: fk0..fk3
+ * </pre>
+ */
+public class ShaderCache {
+    private static final int SLOT_STRIDE = 6;
+    private static final int INITIAL_CAPACITY = 64; // power of 2
+    private static final long EMPTY_MARKER = 0L; // slot [1] == 0 means empty (fkLen >= 1 guarantees nonzero)
+
+    private final Long2ObjectOpenHashMap<String> vertexSourceCache = new Long2ObjectOpenHashMap<>();
+    private final Long2ObjectOpenHashMap<String> geometrySourceCache = new Long2ObjectOpenHashMap<>();
+
+    // Open-addressed table — parallel arrays
+    private long[] keys;
+    private Program[] programs;
+    private String[] fragSources; // fragment source per slot; reused across VK variants via findFragSource
+    private int capacity;
+    private int count;
+    private int uniqueFragCount;
+
+    // Fast-path: last-used key (raw longs, no objects)
+    private long lastVK = Long.MIN_VALUE;
+    private int lastFKLen;
+    private long lastFK0, lastFK1, lastFK2, lastFK3;
+    private Program lastProgram;
+
+    private int fragmentDumpCounter;
+
+    @Setter private Path dumpDir = null;
+
+    public ShaderCache() {
+        capacity = INITIAL_CAPACITY;
+        keys = new long[capacity * SLOT_STRIDE];
+        programs = new Program[capacity];
+        fragSources = new String[capacity];
+    }
+
+    /**
+     * Get or create an FFP program for the given state keys.
+     *
+     * @param vkPacked packed vertex key
+     * @param fkPacked pre-allocated scratch array with packed fragment key longs
+     * @param fkLen number of significant longs in fkPacked (1..4)
+     */
+    public Program getOrCreate(long vkPacked, long[] fkPacked, int fkLen) {
+        // Fast-path: compare raw longs inline
+        if (vkPacked == lastVK && fkLen == lastFKLen && lastProgram != null
+            && fkPacked[0] == lastFK0
+            && (fkLen < 2 || fkPacked[1] == lastFK1)
+            && (fkLen < 3 || fkPacked[2] == lastFK2)
+            && (fkLen < 4 || fkPacked[3] == lastFK3)) {
+            return lastProgram;
+        }
+
+        final long hash = hashKey(vkPacked, fkPacked, fkLen);
+        final long storedWord = ((long) fkLen << 48) | (hash & 0x0000_FFFF_FFFF_FFFFL);
+        final int mask = capacity - 1;
+        int idx = (int) (hash & mask);
+        while (true) {
+            final int base = idx * SLOT_STRIDE;
+            final long slot1 = keys[base + 1];
+            if (slot1 == EMPTY_MARKER) {
+                break;
+            }
+            if (slot1 == storedWord && keys[base] == vkPacked && keysMatch(base + 2, fkPacked, fkLen)) {
+                final Program p = programs[idx];
+                setLastUsed(vkPacked, fkPacked, fkLen, p);
+                return p;
+            }
+            idx = (idx + 1) & mask;
+        }
+
+        if (count >= (capacity * 3) / 4) {
+            grow();
+            return getOrCreate(vkPacked, fkPacked, fkLen);
+        }
+
+        final VertexKey vk = VertexKey.fromPacked(vkPacked);
+        final String vertSrc = getOrGenerateVertex(vk);
+
+        final FragmentKey fk = FragmentKey.fromPacked(fkPacked, fkLen);
+        String fragSrc = findFragSource(fkPacked, fkLen);
+        if (fragSrc == null) {
+            fragSrc = FragmentShaderGenerator.generate(fk);
+            uniqueFragCount++;
+        }
+
+        final String geomSrc = vk.wideLineEmulation() ? getOrGenerateGeometry(vk) : null;
+        final Program program = Program.create(vk, fk, vertSrc, fragSrc, geomSrc);
+
+        final int insertIdx = findEmptySlot(hash);
+        final int base = insertIdx * SLOT_STRIDE;
+        keys[base] = vkPacked;
+        keys[base + 1] = storedWord;
+        for (int i = 0; i < fkLen; i++) keys[base + 2 + i] = fkPacked[i];
+        programs[insertIdx] = program;
+        fragSources[insertIdx] = fragSrc;
+        count++;
+
+        setLastUsed(vkPacked, fkPacked, fkLen, program);
+
+        GLStateManager.LOGGER.debug("FFP variant compiled: {} + {} (total: {} programs)", vk, fk, count);
+
+        if (dumpDir != null) {
+            dumpShader(Long.toHexString(vkPacked), ".vert.glsl", vertSrc);
+            dumpShader("frag_" + fragmentDumpCounter++, ".frag.glsl", fragSrc);
+            if (geomSrc != null) {
+                dumpShader(Long.toHexString(vkPacked), ".geom.glsl", geomSrc);
+            }
+        }
+
+        return program;
+    }
+
+    private String findFragSource(long[] fkPacked, int fkLen) {
+        for (int i = 0; i < capacity; i++) {
+            final int base = i * SLOT_STRIDE;
+            if (keys[base + 1] == EMPTY_MARKER) continue;
+            final int storedLen = (int) (keys[base + 1] >>> 48);
+            if (storedLen != fkLen) continue;
+            if (keysMatch(base + 2, fkPacked, fkLen)) {
+                return fragSources[i];
+            }
+        }
+        return null;
+    }
+
+    private boolean keysMatch(int keysOffset, long[] fkPacked, int fkLen) {
+        for (int i = 0; i < fkLen; i++) {
+            if (keys[keysOffset + i] != fkPacked[i]) return false;
+        }
+        return true;
+    }
+
+    private void setLastUsed(long vkPacked, long[] fkPacked, int fkLen, Program program) {
+        lastVK = vkPacked;
+        lastFKLen = fkLen;
+        lastFK0 = fkPacked[0];
+        lastFK1 = fkLen >= 2 ? fkPacked[1] : 0;
+        lastFK2 = fkLen >= 3 ? fkPacked[2] : 0;
+        lastFK3 = fkLen >= 4 ? fkPacked[3] : 0;
+        lastProgram = program;
+    }
+
+    private int findEmptySlot(long hash) {
+        final int mask = capacity - 1;
+        int idx = (int) (hash & mask);
+        while (keys[idx * SLOT_STRIDE + 1] != EMPTY_MARKER) {
+            idx = (idx + 1) & mask;
+        }
+        return idx;
+    }
+
+    /**
+     * Hash over (vk + fk longs). Adapted from Mesa's hash_key — mix-rotate-multiply.
+     */
+    private static long hashKey(long vkPacked, long[] fkPacked, int fkLen) {
+        long h = vkPacked * 0x9E3779B97F4A7C15L;
+        for (int i = 0; i < fkLen; i++) {
+            h ^= fkPacked[i] * 0x517CC1B727220A95L;
+            h = Long.rotateLeft(h, 31) * 0x9E3779B97F4A7C15L;
+        }
+        return h | 1L; // ensure nonzero lower bits
+    }
+
+    private void grow() {
+        final int oldCap = capacity;
+        final long[] oldKeys = keys;
+        final Program[] oldPrograms = programs;
+        final String[] oldFragSources = fragSources;
+
+        capacity = oldCap * 2;
+        keys = new long[capacity * SLOT_STRIDE];
+        programs = new Program[capacity];
+        fragSources = new String[capacity];
+        count = 0;
+
+        final int mask = capacity - 1;
+        for (int i = 0; i < oldCap; i++) {
+            final int oldBase = i * SLOT_STRIDE;
+            if (oldKeys[oldBase + 1] == EMPTY_MARKER) continue;
+
+            final long storedHash = oldKeys[oldBase + 1] & 0x0000_FFFF_FFFF_FFFFL;
+            int idx = (int) (storedHash & mask);
+            while (keys[idx * SLOT_STRIDE + 1] != EMPTY_MARKER) {
+                idx = (idx + 1) & mask;
+            }
+            final int newBase = idx * SLOT_STRIDE;
+            System.arraycopy(oldKeys, oldBase, keys, newBase, SLOT_STRIDE);
+            programs[idx] = oldPrograms[i];
+            fragSources[idx] = oldFragSources[i];
+            count++;
+        }
+    }
+
+    private String getOrGenerateVertex(VertexKey vk) {
+        return vertexSourceCache.computeIfAbsent(vk.pack(), k -> VertexShaderGenerator.generate(vk));
+    }
+
+    private String getOrGenerateGeometry(VertexKey vk) {
+        return geometrySourceCache.computeIfAbsent(vk.pack(), k -> GeometryShaderGenerator.generate(vk));
+    }
+
+    private void dumpShader(String name, String suffix, String source) {
+        if (dumpDir == null) return;
+        try {
+            Files.createDirectories(dumpDir);
+            final Path file = dumpDir.resolve("ffp_" + name + suffix);
+            if (!Files.exists(file)) {
+                Files.writeString(file, source, StandardCharsets.UTF_8);
+            }
+        } catch (IOException e) {
+            GLStateManager.LOGGER.warn("Failed to dump FFP shader to {}: {}", dumpDir, e.getMessage());
+        }
+    }
+
+    /** Dump all cached shaders to disk. */
+    public void dumpAll(Path outputDir) {
+        try {
+            Files.createDirectories(outputDir);
+            for (var entry : vertexSourceCache.entrySet()) {
+                dumpShader(Long.toHexString(entry.getKey()), ".vert.glsl", entry.getValue());
+            }
+            final IdentityHashMap<String, Integer> seen = new IdentityHashMap<>();
+            for (int i = 0; i < capacity; i++) {
+                if (fragSources[i] != null && !seen.containsKey(fragSources[i])) {
+                    final int idx = seen.size();
+                    seen.put(fragSources[i], idx);
+                    dumpShader("frag_" + idx, ".frag.glsl", fragSources[i]);
+                }
+            }
+            for (var entry : geometrySourceCache.entrySet()) {
+                dumpShader(Long.toHexString(entry.getKey()), ".geom.glsl", entry.getValue());
+            }
+            GLStateManager.LOGGER.info("Dumped {} vertex, {} geometry, and {} fragment FFP shader sources to {}",
+                vertexSourceCache.size(), geometrySourceCache.size(), seen.size(), outputDir);
+        } catch (IOException e) {
+            GLStateManager.LOGGER.warn("Failed to dump FFP shaders: {}", e.getMessage());
+        }
+    }
+
+    /** Destroy all cached programs and clear caches. */
+    public void destroy() {
+        for (int i = 0; i < capacity; i++) {
+            if (programs[i] != null) {
+                programs[i].destroy();
+            }
+        }
+        Arrays.fill(keys, 0);
+        Arrays.fill(programs, null);
+        Arrays.fill(fragSources, null);
+        count = 0;
+        uniqueFragCount = 0;
+        vertexSourceCache.clear();
+        geometrySourceCache.clear();
+        lastProgram = null;
+        lastVK = Long.MIN_VALUE;
+        GLStateManager.LOGGER.debug("FFP shader cache cleared");
+    }
+
+    public int getProgramCount() {
+        return count;
+    }
+
+    public int getVertexVariantCount() {
+        return vertexSourceCache.size();
+    }
+
+    public int getFragmentVariantCount() {
+        return uniqueFragCount;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/ShaderManager.java

@@ -0,0 +1,198 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
+import com.gtnewhorizons.angelica.glsm.CompatUniformManager;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.hooks.DeferredBlendHandler;
+import com.gtnewhorizons.angelica.glsm.hooks.GLSMHooks;
+import com.gtnewhorizons.angelica.glsm.hooks.GLSMInitConfig;
+import com.gtnewhorizons.angelica.glsm.QuadConverter;
+import com.gtnewhorizons.angelica.glsm.stacks.Vec3fStack;
+import com.gtnewhorizons.angelica.glsm.stacks.Vec4fStack;
+import com.gtnewhorizons.angelica.glsm.streaming.TessellatorStreamingDrawer;
+import lombok.Getter;
+import org.joml.Vector3f;
+import org.joml.Vector4f;
+
+import java.nio.file.Paths;
+import java.util.Arrays;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * FFP shader manager
+ */
+public final class ShaderManager {
+
+    private static final class Holder {
+
+        static final ShaderManager INSTANCE = new ShaderManager();
+    }
+
+    private final ShaderCache cache = new ShaderCache();
+    private final Uniforms uniforms = new Uniforms();
+
+    @Getter
+    private boolean active = false;
+    private Program currentProgram = null;
+    private int lastBoundProgramId = -1;
+    private long currentVertexKeyPacked = Long.MIN_VALUE;
+    private final long[] currentFKScratch = new long[FragmentKey.MAX_UNITS];
+    private final long[] currentFKPacked = new long[FragmentKey.MAX_UNITS];
+    private int currentFKLen = 0;
+
+    @Getter private static final Vector3f currentNormal = new Vector3f(0.0f, 0.0f, 1.0f);
+    private static final Vector4f[] currentTexCoords = {
+        new Vector4f(0.0f, 0.0f, 0.0f, 1.0f),
+        new Vector4f(0.0f, 0.0f, 0.0f, 1.0f),
+        new Vector4f(0.0f, 0.0f, 0.0f, 1.0f),
+        new Vector4f(0.0f, 0.0f, 0.0f, 1.0f),
+    };
+    @Getter private static final Vec3fStack normalStack = new Vec3fStack(currentNormal);
+    @Getter private static final Vec4fStack texCoordStack = new Vec4fStack(currentTexCoords[0]);
+    @Getter private static int normalGeneration;
+    @Getter private static int texCoordGeneration;
+
+    public static Vector4f getCurrentTexCoord() { return currentTexCoords[0]; }
+    public static Vector4f getCurrentTexCoord(int unit) { return currentTexCoords[unit]; }
+    @Getter private boolean enabled = false;
+
+    private ShaderManager() {
+        if (Boolean.parseBoolean(System.getProperty("angelica.dumpShaders", "false"))) {
+            cache.setDumpDir(Paths.get("ffp_shaders"));
+        }
+    }
+
+    public static ShaderManager getInstance() {
+        return Holder.INSTANCE;
+    }
+
+    public void enable() {
+        warmUp();
+        enabled = true;
+
+        GLStateManager.LOGGER.info("FFP shader emulation enabled");
+    }
+
+    // Force loading of classes before the SplashThread kicks off
+    // Ensure it's GL free
+    private static void warmUp() {
+        try {
+            final long[] fkScratch = new long[FragmentKey.MAX_UNITS];
+            final int fkLen = FragmentKey.packFromState(fkScratch);
+            final int fragMask = FragmentKey.unitMaskFromPacked(fkScratch, fkLen);
+            final long vkPacked = VertexKey.packFromState(true, true, true, true, fragMask);
+            final VertexKey vk = VertexKey.fromPacked(vkPacked);
+            VertexShaderGenerator.generate(vk);
+            FragmentShaderGenerator.generate(FragmentKey.fromPacked(fkScratch, fkLen));
+            GeometryShaderGenerator.generate(vk);
+            final Class<?>[] touched = { Program.class, ShaderCache.class, TessellatorStreamingDrawer.class, QuadConverter.class };
+            for (Class<?> c : touched) {
+                c.getName();
+            }
+        } catch (Throwable t) {
+            GLStateManager.LOGGER.warn("FFP warmup failed; draw-path classes will resolve lazily", t);
+        }
+    }
+
+    public void disable() {
+        enabled = false;
+    }
+
+    public void activate() {
+        active = true;
+        lastBoundProgramId = GLStateManager.getActiveProgram();
+    }
+
+    public void deactivate() {
+        active = false;
+        currentProgram = null;
+        lastBoundProgramId = -1;
+        currentVertexKeyPacked = Long.MIN_VALUE;
+        currentFKLen = 0;
+    }
+
+    public void preDraw() {
+        final DeferredBlendHandler bh = GLSMHooks.blendHandler;
+        if (bh != null) bh.flushDeferredBlend();
+
+        // Handle FFP & Iris uniforms
+        final int currentProgramId = GLStateManager.getActiveProgram();
+        if (currentProgramId != 0) {
+            if (!CompatUniformManager.refreshCompatUniforms(currentProgramId)) {
+                return; // Don't emulate FFP on non-iris core shaders
+            }
+        }
+
+        final int vertexFlags = VAOManager.getCurrentVertexFlags();
+        final boolean hasColor = (vertexFlags & VertexFlags.COLOR_BIT) != 0;
+        final boolean hasNormal =   (vertexFlags & VertexFlags.NORMAL_BIT) != 0;
+        final boolean hasTexCoord = (vertexFlags & VertexFlags.TEXTURE_BIT) != 0;
+        final boolean hasLightmap = (vertexFlags & VertexFlags.BRIGHTNESS_BIT) != 0;
+        GLStateManager.flushDeferredVertexAttribs(hasColor, hasNormal, hasTexCoord, hasLightmap);
+
+        if (!active) return;
+
+
+        final int fkLen = FragmentKey.packFromState(currentFKScratch);
+        final int fragMask = FragmentKey.unitMaskFromPacked(currentFKScratch, fkLen);
+        final long vkPacked = VertexKey.packFromState(hasColor, hasNormal, hasTexCoord, hasLightmap, fragMask);
+
+        if (vkPacked != currentVertexKeyPacked || !Arrays.equals(currentFKScratch, 0, fkLen, currentFKPacked, 0, currentFKLen)) {
+            commitVariant(vkPacked, fkLen);
+        }
+
+        uploadUniforms();
+    }
+
+    private void commitVariant(long vkPacked, int fkLen) {
+        currentVertexKeyPacked = vkPacked;
+        System.arraycopy(currentFKScratch, 0, currentFKPacked, 0, fkLen);
+        currentFKLen = fkLen;
+        currentProgram = cache.getOrCreate(vkPacked, currentFKPacked, currentFKLen);
+        final int programId = currentProgram.getProgramId();
+        if (programId != lastBoundProgramId) {
+            RENDER_BACKEND.useProgram(programId);
+            lastBoundProgramId = programId;
+        }
+    }
+
+    private void uploadUniforms() {
+        if (currentProgram != null) {
+            uniforms.upload(currentProgram);
+        }
+    }
+
+    public static void setCurrentNormal(float x, float y, float z) {
+        currentNormal.set(x, y, z);
+        normalGeneration++;
+    }
+
+    public static void setCurrentTexCoord(float s, float t, float r, float q) {
+        currentTexCoords[0].set(s, t, r, q);
+        texCoordGeneration++;
+    }
+
+    public static void setCurrentTexCoord(int unit, float s, float t, float r, float q) {
+        currentTexCoords[unit].set(s, t, r, q);
+        texCoordGeneration++;
+    }
+
+    public static void bumpNormalGeneration() { normalGeneration++; }
+    public static void bumpTexCoordGeneration() { texCoordGeneration++; }
+
+    public void destroy() {
+        cache.destroy();
+        uniforms.destroy();
+        final GLSMInitConfig config = GLStateManager.getInitConfig();
+        if (config != null && config.getStreamingDrawerDestroy() != null) config.getStreamingDrawerDestroy().run();
+        com.gtnewhorizons.angelica.glsm.QuadConverter.destroy();
+        active = false;
+        currentProgram = null;
+    }
+
+    public String getDebugInfo() {
+        return String.format("FFP: %d programs (%d vert, %d frag variants)",
+            cache.getProgramCount(), cache.getVertexVariantCount(), cache.getFragmentVariantCount());
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/Uniforms.java

@@ -0,0 +1,483 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.states.ClipPlaneState;
+import com.gtnewhorizons.angelica.glsm.states.FogState;
+import com.gtnewhorizons.angelica.glsm.states.LightState;
+import com.gtnewhorizons.angelica.glsm.states.MaterialState;
+import com.gtnewhorizons.angelica.glsm.states.TexGenState;
+import com.gtnewhorizons.angelica.glsm.hooks.GLSMConfig;
+import org.joml.Math;
+import org.joml.Matrix3f;
+import org.joml.Matrix4f;
+import org.joml.Vector4f;
+
+import java.nio.FloatBuffer;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAllocFloat;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memFree;
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * Uploads GLSM cached state to the active FFP program's uniforms.
+ *
+ * Follows Mesa's prog_statevars.c patterns:
+ * - Pre-computed derived state (light products, scene color) when material is static
+ * - Raw light/material values when color material is active
+ * - Optimized fog params (pre-divided for single MAD in shader)
+ */
+public class Uniforms {
+    // Reusable temp buffers for uniform upload
+    private final FloatBuffer mat4Buf = memAllocFloat(16);
+    private final FloatBuffer mat3Buf = memAllocFloat(9);
+    private final FloatBuffer vec4Buf = memAllocFloat(4);
+    private final FloatBuffer vec3Buf = memAllocFloat(3);
+    private final FloatBuffer clipPlaneBuf = memAllocFloat(32); // 8 planes * vec4
+
+    // Derived matrices (computed on CPU)
+    private final Matrix4f mvpMatrix = new Matrix4f();
+    private final Matrix3f normalMatrix = new Matrix3f();
+
+    // Temp vectors for light product and normal scale computation
+    private final Vector4f tempVec4 = new Vector4f();
+    private final org.joml.Vector3f tempVec3 = new org.joml.Vector3f();
+
+    // Pre-computed constants for fog params (Mesa STATE_FOG_PARAMS_OPTIMIZED)
+    private static final double LN2 = java.lang.Math.log(2.0);
+    private static final double SQRT_LN2 = java.lang.Math.sqrt(LN2);
+
+    /**
+     * Upload all relevant uniforms to the given FFP program based on current GLSM state.
+     * Uses generation counters to skip categories that haven't changed since last upload.
+     */
+    public void upload(Program program) {
+        final Program.UploadState st = program.uploadState;
+
+        final int mvGen = GLStateManager.mvGeneration;
+        final int mvLinearGen = GLStateManager.mvLinearGeneration;
+        final int projGen = GLStateManager.projGeneration;
+        final int texMatGen = GLStateManager.texMatrixGeneration;
+        final boolean mvChanged = mvGen != st.mvGen;
+        final boolean mvLinearChanged = mvLinearGen != st.mvLinearGen;
+        final boolean projChanged = projGen != st.projGen;
+        final boolean texMatChanged = texMatGen != st.texMatGen;
+        if (mvChanged || projChanged || texMatChanged) {
+            uploadMatrices(program, mvChanged, mvLinearChanged, projChanged, texMatChanged);
+            st.mvGen = mvGen;
+            st.mvLinearGen = mvLinearGen;
+            st.projGen = projGen;
+            st.texMatGen = texMatGen;
+        }
+
+        if (program.getVertexKey().lightingEnabled()) {
+            final int litGen = GLStateManager.lightingGeneration;
+            if (litGen != st.lightingGen) {
+                uploadLighting(program);
+                st.lightingGen = litGen;
+            }
+        }
+
+        // Current color/normal/texcoord — skip if generation unchanged
+        if (!program.getVertexKey().hasVertexColor()) {
+            final int colorGen = GLStateManager.colorGeneration;
+            if (colorGen != st.colorGen) {
+                uploadCurrentColor(program);
+                st.colorGen = colorGen;
+            }
+        }
+
+        if (!program.getVertexKey().hasVertexNormal() && program.getVertexKey().lightingEnabled()) {
+            final int normalGen = ShaderManager.getNormalGeneration();
+            if (normalGen != st.normalGen) {
+                uploadCurrentNormal(program);
+                st.normalGen = normalGen;
+            }
+        }
+
+        if (program.getVertexKey().anyUnitTexCoordEnabled()) {
+            final int texGen = ShaderManager.getTexCoordGeneration();
+            if (texGen != st.texCoordGen) {
+                uploadCurrentTexCoords(program);
+                st.texCoordGen = texGen;
+            }
+        }
+
+        if (program.getVertexKey().lightmapEnabled() && !program.getVertexKey().hasVertexLightmap()) {
+            if (GLSMConfig.lastBrightnessX != st.lightmapX || GLSMConfig.lastBrightnessY != st.lightmapY) {
+                uploadCurrentLightmapCoord(program);
+                st.lightmapX = GLSMConfig.lastBrightnessX;
+                st.lightmapY = GLSMConfig.lastBrightnessY;
+            }
+        }
+
+        if (program.getVertexKey().texGenEnabled()) {
+            final int tgGen = GLStateManager.texGenGeneration;
+            if (tgGen != st.texGenGen) {
+                uploadTexGen(program);
+                st.texGenGen = tgGen;
+            }
+        }
+
+        if (program.getVertexKey().clipPlanesEnabled()) {
+            final int cpGen = GLStateManager.clipPlaneGeneration;
+            if (cpGen != st.clipPlaneGen) {
+                uploadClipPlanes(program);
+                st.clipPlaneGen = cpGen;
+            }
+        }
+
+        final int fragGen = GLStateManager.fragmentGeneration;
+        if (fragGen != st.fragmentGen) {
+            uploadFragmentUniforms(program);
+            st.fragmentGen = fragGen;
+        }
+
+        // Wide line emulation uniforms
+        if (program.locLineWidth != -1 && program.locViewportSize != -1) {
+            uploadWideLineUniforms(program);
+        }
+    }
+
+    private void uploadMatrices(Program program, boolean mvChanged, boolean mvLinearChanged, boolean projChanged, boolean texMatChanged) {
+        final Matrix4f mv = GLStateManager.getModelViewMatrix();
+        final Matrix4f proj = GLStateManager.getProjectionMatrix();
+
+        // ModelView + derived (normal matrix, normal scale)
+        if (mvChanged) {
+            if (program.locModelViewMatrix != -1) {
+                mv.get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(program.locModelViewMatrix, false, mat4Buf);
+            }
+        }
+
+        if (mvLinearChanged) {
+            // Normal matrix = inverse transpose of upper-left 3x3 of ModelView
+            if (program.locNormalMatrix != -1 || program.locNormalScale != -1) {
+                mv.normal(normalMatrix);
+            }
+            if (program.locNormalMatrix != -1) {
+                normalMatrix.get(mat3Buf);
+                RENDER_BACKEND.uniformMatrix3(program.locNormalMatrix, false, mat3Buf);
+            }
+
+            // Normal scale (for GL_RESCALE_NORMAL without GL_NORMALIZE)
+            if (program.locNormalScale != -1) {
+                // Scale factor = 1/length of first column of normal matrix
+                final float scale = 1.0f / normalMatrix.getColumn(0, tempVec3).length();
+                RENDER_BACKEND.uniform1f(program.locNormalScale, scale);
+            }
+        }
+
+        // Projection
+        if (projChanged) {
+            if (program.locProjectionMatrix != -1) {
+                proj.get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(program.locProjectionMatrix, false, mat4Buf);
+            }
+        }
+
+        // MVP = Projection * ModelView — needs recompute if either input changed
+        if ((mvChanged || projChanged) && program.locMVPMatrix != -1) {
+            proj.mul(mv, mvpMatrix);
+            mvpMatrix.get(mat4Buf);
+            RENDER_BACKEND.uniformMatrix4(program.locMVPMatrix, false, mat4Buf);
+        }
+
+        // Texture matrices (per-unit).
+        if (texMatChanged) {
+            for (int i = 0; i < 4; i++) {
+                if (program.locTextureMatrix[i] != -1) {
+                    final Matrix4f texMat = GLStateManager.getTextures().getTextureUnitMatrix(i);
+                    texMat.get(mat4Buf);
+                    RENDER_BACKEND.uniformMatrix4(program.locTextureMatrix[i], false, mat4Buf);
+                }
+            }
+            if (program.locLightmapTextureMatrix != -1) {
+                final Matrix4f lmTexMat = GLStateManager.getTextures().getTextureUnitMatrix(1);
+                lmTexMat.get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(program.locLightmapTextureMatrix, false, mat4Buf);
+            }
+        }
+    }
+
+    private void uploadLighting(Program program) {
+        final VertexKey vk = program.getVertexKey();
+
+        if (vk.colorMaterialEnabled()) {
+            uploadLightingColorMaterial(program, vk);
+        } else {
+            uploadLightingPreComputed(program, vk);
+        }
+    }
+
+    /**
+     * Color material active: upload raw light and material values.
+     * The shader multiplies them with vertex color at runtime.
+     */
+    private void uploadLightingColorMaterial(Program program, VertexKey vk) {
+        final MaterialState mat = GLStateManager.getFrontMaterial();
+
+        uploadVec4(program.locLightModelAmbient, GLStateManager.getLightModel().ambient);
+        uploadVec4(program.locMaterialEmission, mat.emission);
+        uploadVec4(program.locMaterialAmbient, mat.ambient);
+        uploadVec4(program.locMaterialDiffuse, mat.diffuse);
+        uploadVec4(program.locMaterialSpecular, mat.specular);
+        if (program.locMaterialShininess != -1) {
+            RENDER_BACKEND.uniform1f(program.locMaterialShininess, mat.shininess);
+        }
+
+        if (vk.light0Enabled()) {
+            final LightState light0 = GLStateManager.getLightDataStates()[0];
+            uploadVec4(program.locLight0Ambient, light0.ambient);
+            uploadVec4(program.locLight0Diffuse, light0.diffuse);
+            uploadVec4(program.locLight0Specular, light0.specular);
+            uploadVec4(program.locLight0Position, light0.position);
+        }
+        if (vk.light1Enabled()) {
+            final LightState light1 = GLStateManager.getLightDataStates()[1];
+            uploadVec4(program.locLight1Ambient, light1.ambient);
+            uploadVec4(program.locLight1Diffuse, light1.diffuse);
+            uploadVec4(program.locLight1Specular, light1.specular);
+            uploadVec4(program.locLight1Position, light1.position);
+        }
+    }
+
+    /**
+     * No color material: upload pre-computed light products and scene color.
+     * Fewer shader multiplies since material is static.
+     */
+    private void uploadLightingPreComputed(Program program, VertexKey vk) {
+        final MaterialState mat = GLStateManager.getFrontMaterial();
+
+        // Scene color = emission + ambient * lightModel.ambient
+        // Alpha = material.diffuse.a
+        if (program.locSceneColor != -1) {
+            tempVec4.set(
+                mat.emission.x + mat.ambient.x * GLStateManager.getLightModel().ambient.x,
+                mat.emission.y + mat.ambient.y * GLStateManager.getLightModel().ambient.y,
+                mat.emission.z + mat.ambient.z * GLStateManager.getLightModel().ambient.z,
+                mat.diffuse.w  // alpha from diffuse
+            );
+            uploadVec4(program.locSceneColor, tempVec4);
+        }
+
+        if (program.locMaterialShininess != -1) {
+            RENDER_BACKEND.uniform1f(program.locMaterialShininess, mat.shininess);
+        }
+
+        // Per-light products
+        if (vk.light0Enabled()) {
+            final LightState light0 = GLStateManager.getLightDataStates()[0];
+            uploadVec4(program.locLight0Position, light0.position);
+            uploadLightProduct(program.locLightProd0Ambient, light0.ambient, mat.ambient);
+            uploadLightProduct(program.locLightProd0Diffuse, light0.diffuse, mat.diffuse);
+            uploadLightProduct(program.locLightProd0Specular, light0.specular, mat.specular);
+        }
+        if (vk.light1Enabled()) {
+            final LightState light1 = GLStateManager.getLightDataStates()[1];
+            uploadVec4(program.locLight1Position, light1.position);
+            uploadLightProduct(program.locLightProd1Ambient, light1.ambient, mat.ambient);
+            uploadLightProduct(program.locLightProd1Diffuse, light1.diffuse, mat.diffuse);
+            uploadLightProduct(program.locLightProd1Specular, light1.specular, mat.specular);
+        }
+    }
+
+    /**
+     * Upload pre-multiplied light product: light.X * material.X (RGB only).
+     */
+    private void uploadLightProduct(int loc, Vector4f lightVal, Vector4f materialVal) {
+        if (loc == -1) return;
+        vec3Buf.clear();
+        vec3Buf.put(lightVal.x * materialVal.x);
+        vec3Buf.put(lightVal.y * materialVal.y);
+        vec3Buf.put(lightVal.z * materialVal.z);
+        vec3Buf.flip();
+        RENDER_BACKEND.uniform3(loc, vec3Buf);
+    }
+
+    private void uploadCurrentColor(Program program) {
+        if (program.locCurrentColor == -1) return;
+        // Upload the current color from GLSM
+        final var color = GLStateManager.getColor();
+        tempVec4.set(
+            Math.clamp(0f, 1f, color.getRed()),
+            Math.clamp(0f, 1f, color.getGreen()),
+            Math.clamp(0f, 1f, color.getBlue()),
+            Math.clamp(0f, 1f, color.getAlpha()));
+        vec4Buf.clear();
+        tempVec4.get(vec4Buf);
+        RENDER_BACKEND.uniform4(program.locCurrentColor, vec4Buf);
+    }
+
+    private void uploadCurrentTexCoords(Program program) {
+        for (int i = 0; i < 4; i++) {
+            if (program.locCurrentTexCoord[i] != -1) {
+                uploadVec4(program.locCurrentTexCoord[i], ShaderManager.getCurrentTexCoord(i));
+            }
+        }
+    }
+
+    private void uploadCurrentLightmapCoord(Program program) {
+        if (program.locCurrentLightmapCoord == -1) return;
+        RENDER_BACKEND.uniform2f(program.locCurrentLightmapCoord,
+            GLSMConfig.lastBrightnessX, GLSMConfig.lastBrightnessY);
+    }
+
+    private void uploadCurrentNormal(Program program) {
+        if (program.locCurrentNormal == -1) return;
+        // Upload current normal from FFPShaderManager's tracked normal
+        final var normal = ShaderManager.getCurrentNormal();
+        vec3Buf.clear();
+        normal.get(vec3Buf);
+        RENDER_BACKEND.uniform3(program.locCurrentNormal, vec3Buf);
+    }
+
+    private void uploadTexGen(Program program) {
+        final VertexKey vk = program.getVertexKey();
+        final TexGenState tg = GLStateManager.getTextures().getTexGenState(0);
+
+        if (vk.texGenModeS() == VertexKey.TG_OBJ_LINEAR) {
+            uploadPlane(program.locTexGenObjPlaneS, tg.getObjectPlane(org.lwjgl.opengl.GL11.GL_S));
+        } else if (vk.texGenModeS() == VertexKey.TG_EYE_LINEAR) {
+            uploadPlane(program.locTexGenEyePlaneS, tg.getEyePlane(org.lwjgl.opengl.GL11.GL_S));
+        }
+
+        if (vk.texGenModeT() == VertexKey.TG_OBJ_LINEAR) {
+            uploadPlane(program.locTexGenObjPlaneT, tg.getObjectPlane(org.lwjgl.opengl.GL11.GL_T));
+        } else if (vk.texGenModeT() == VertexKey.TG_EYE_LINEAR) {
+            uploadPlane(program.locTexGenEyePlaneT, tg.getEyePlane(org.lwjgl.opengl.GL11.GL_T));
+        }
+
+        if (vk.texGenModeR() == VertexKey.TG_OBJ_LINEAR) {
+            uploadPlane(program.locTexGenObjPlaneR, tg.getObjectPlane(org.lwjgl.opengl.GL11.GL_R));
+        } else if (vk.texGenModeR() == VertexKey.TG_EYE_LINEAR) {
+            uploadPlane(program.locTexGenEyePlaneR, tg.getEyePlane(org.lwjgl.opengl.GL11.GL_R));
+        }
+
+        if (vk.texGenModeQ() == VertexKey.TG_OBJ_LINEAR) {
+            uploadPlane(program.locTexGenObjPlaneQ, tg.getObjectPlane(org.lwjgl.opengl.GL11.GL_Q));
+        } else if (vk.texGenModeQ() == VertexKey.TG_EYE_LINEAR) {
+            uploadPlane(program.locTexGenEyePlaneQ, tg.getEyePlane(org.lwjgl.opengl.GL11.GL_Q));
+        }
+    }
+
+    private void uploadPlane(int loc, float[] plane) {
+        if (loc == -1) return;
+        vec4Buf.clear();
+        vec4Buf.put(plane, 0, 4);
+        vec4Buf.flip();
+        RENDER_BACKEND.uniform4(loc, vec4Buf);
+    }
+
+    private void uploadClipPlanes(Program program) {
+        if (program.locClipPlanes == -1) return;
+        final ClipPlaneState cps = GLStateManager.getClipPlaneState();
+        clipPlaneBuf.clear();
+        for (int i = 0; i < GLStateManager.MAX_CLIP_PLANES; i++) {
+            cps.putEyePlane(i, clipPlaneBuf);
+        }
+        clipPlaneBuf.flip();
+        RENDER_BACKEND.uniform4(program.locClipPlanes, clipPlaneBuf);
+    }
+
+    private void uploadFragmentUniforms(Program program) {
+        final FragmentKey fk = program.getFragmentKey();
+
+        // Alpha test reference
+        if (fk.alphaTestEnabled() && program.locAlphaRef != -1) {
+            RENDER_BACKEND.uniform1f(program.locAlphaRef, GLStateManager.getAlphaState().getReference());
+        }
+
+        // Per-unit tex env color
+        for (int i = 0; i < 4; i++) {
+            if (program.locTexEnvColor[i] != -1) {
+                final var envState = GLStateManager.getTextures().getTexEnvState(i);
+                vec4Buf.clear();
+                vec4Buf.put(envState.envColorR);
+                vec4Buf.put(envState.envColorG);
+                vec4Buf.put(envState.envColorB);
+                vec4Buf.put(envState.envColorA);
+                vec4Buf.flip();
+                RENDER_BACKEND.uniform4(program.locTexEnvColor[i], vec4Buf);
+            }
+        }
+
+        if (fk.overlayEnabled() && program.locOverlayColor != -1) {
+            vec4Buf.clear();
+            vec4Buf.put(GLStateManager.getOverlayR());
+            vec4Buf.put(GLStateManager.getOverlayG());
+            vec4Buf.put(GLStateManager.getOverlayB());
+            vec4Buf.put(GLStateManager.getOverlayA());
+            vec4Buf.flip();
+            RENDER_BACKEND.uniform4(program.locOverlayColor, vec4Buf);
+        }
+
+        // Fog
+        if (fk.fogMode() != FragmentKey.FOG_NONE) {
+            uploadFog(program);
+        }
+    }
+
+    /**
+     * Upload optimized fog params (following Mesa's STATE_FOG_PARAMS_OPTIMIZED):
+     */
+    private void uploadFog(Program program) {
+        final FogState fog = GLStateManager.getFogState();
+
+        if (program.locFogParams != -1) {
+            final float start = fog.getStart();
+            final float end = fog.getEnd();
+            final float density = fog.getDensity();
+            final float range = end - start;
+
+            vec4Buf.clear();
+            vec4Buf.put(range != 0.0f ? -1.0f / range : 0.0f);     // [0]: -1/(end-start)
+            vec4Buf.put(range != 0.0f ? end / range : 1.0f);         // [1]: end/(end-start)
+            vec4Buf.put((float)(density / LN2));        // [2]: density/ln(2)
+            vec4Buf.put((float)(density / SQRT_LN2));  // [3]: density/sqrt(ln(2))
+            vec4Buf.flip();
+            RENDER_BACKEND.uniform4(program.locFogParams, vec4Buf);
+        }
+
+        if (program.locFogColor != -1) {
+            vec4Buf.clear();
+            vec4Buf.put((float) fog.getFogColor().x);
+            vec4Buf.put((float) fog.getFogColor().y);
+            vec4Buf.put((float) fog.getFogColor().z);
+            vec4Buf.put(fog.getFogAlpha());
+            vec4Buf.flip();
+            RENDER_BACKEND.uniform4(program.locFogColor, vec4Buf);
+        }
+    }
+
+    private void uploadWideLineUniforms(Program program) {
+        final Program.UploadState st = program.uploadState;
+        final float lineWidth = GLStateManager.getLineState().getWidth();
+        if (lineWidth != st.lineWidth) {
+            RENDER_BACKEND.uniform1f(program.locLineWidth, lineWidth);
+            st.lineWidth = lineWidth;
+        }
+        final int vw = GLStateManager.getViewportState().width;
+        final int vh = GLStateManager.getViewportState().height;
+        if (vw != st.viewportWidth || vh != st.viewportHeight) {
+            RENDER_BACKEND.uniform2f(program.locViewportSize, vw, vh);
+            st.viewportWidth = vw;
+            st.viewportHeight = vh;
+        }
+    }
+
+    private void uploadVec4(int loc, Vector4f v) {
+        if (loc == -1) return;
+        vec4Buf.clear();
+        v.get(vec4Buf);
+        RENDER_BACKEND.uniform4(loc, vec4Buf);
+    }
+
+    public void destroy() {
+        memFree(mat4Buf);
+        memFree(mat3Buf);
+        memFree(vec4Buf);
+        memFree(vec3Buf);
+        memFree(clipPlaneBuf);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/VAOManager.java

@@ -0,0 +1,321 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+
+import javax.annotation.Nullable;
+import java.nio.ByteBuffer;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+public final class VAOManager {
+    public static final int MAX_ATTRIBS = 16;
+
+    public static final Int2ObjectOpenHashMap<VAOData> vaoMap = new Int2ObjectOpenHashMap<>();
+
+    private static VAOData current = null;
+    private static int currentVertexFlags = 0;
+    private static Attrib[] currentAttribs = null;
+    public static int boundEBO = 0;
+
+    private static int clientSideEnabledCount = 0;
+
+
+    public static void init(int defaultVAO) {
+        final VAOData data = new VAOData();
+        current = data;
+        currentAttribs = data.attribs;
+        vaoMap.put(defaultVAO, data);
+    }
+
+    public static void onBindEBO(int ebo) {
+        boundEBO = ebo;
+    }
+
+    public static void onBindVertexArrayPre(int vaoId) {
+        // Save old VAO data
+        if (current != null) {
+            current.vertexFlags = currentVertexFlags;
+            current.ebo = boundEBO;
+            current.attribs = currentAttribs;
+            current.clientSideEnabledCount = clientSideEnabledCount;
+        }
+
+        VAOData data = vaoMap.get(vaoId);
+        if (data == null) {
+            data = new VAOData();
+            vaoMap.put(vaoId, data);
+        }
+        current = data;
+        currentVertexFlags = data.vertexFlags;
+        currentAttribs = data.attribs;
+        boundEBO = data.ebo;
+        clientSideEnabledCount = data.clientSideEnabledCount;
+    }
+
+    public static void onDeleteVertexArray(int vaoId) {
+        vaoMap.remove(vaoId);
+    }
+
+    public static void enableClientVertexFlag(int flag) { currentVertexFlags |= flag; }
+    public static void disableClientVertexFlag(int flag) { currentVertexFlags &= ~flag; }
+    public static int getCurrentVertexFlags() { return currentVertexFlags; }
+    public static void setCurrentVertexFlags(int flags) { currentVertexFlags = flags; }
+
+    public static final class VAOData {
+        public Attrib[] attribs;
+        public int vertexFlags;
+        public int ebo;
+        public int clientSideEnabledCount;
+
+        public VAOData() {
+            attribs = new Attrib[MAX_ATTRIBS];
+        }
+    }
+
+    public static void setAttribute(int index, int size, int type, boolean normalized, int stride, long offset, int vboId) {
+        if (index < 0 || index >= MAX_ATTRIBS) return;
+        final Attrib a = getAttrib(index);
+        final boolean wasClient = a.clientPointer != null;
+        a.size = size;
+        a.type = type;
+        a.normalized = normalized;
+        a.stride = stride;
+        a.offset = offset;
+        a.vboId = vboId;
+        a.clientPointer = null;
+        a.genericPointer = true;
+        if (wasClient && a.enabled) {
+            clientSideEnabledCount--;
+        }
+    }
+
+    public static void setAttribute(int index, int size, int type, boolean normalized, int stride, ByteBuffer pointer) {
+        if (index < 0 || index >= MAX_ATTRIBS) return;
+        final Attrib a = getAttrib(index);
+        final boolean wasClient = a.clientPointer != null;
+        a.size = size;
+        a.type = type;
+        a.normalized = normalized;
+        a.stride = stride;
+        a.offset = 0;
+        a.vboId = 0;
+        a.clientPointer = pointer;
+        a.genericPointer = true;
+        if (!wasClient && a.enabled) {
+            clientSideEnabledCount++;
+        }
+    }
+
+    public static boolean isGenericPointerEnabled(int index) {
+        if (index < 0 || index >= MAX_ATTRIBS) return false;
+        final Attrib a = currentAttribs[index];
+        return a != null && a.genericPointer && a.enabled;
+    }
+
+    public static void markConventional(int index) {
+        if (index < 0 || index >= MAX_ATTRIBS) return;
+        final Attrib a = currentAttribs[index];
+        if (a != null) a.genericPointer = false;
+    }
+
+    public static void setEnabled(int index, boolean enabled) {
+        if (index < 0 || index >= MAX_ATTRIBS) return;
+        final Attrib a = getAttrib(index);
+        if (a.clientPointer != null && a.enabled != enabled) {
+            clientSideEnabledCount += enabled ? 1 : -1;
+        }
+        a.enabled = enabled;
+    }
+
+    public static void enableAttribute(int index) {
+        if (index < 0 || index >= MAX_ATTRIBS) return;
+        final Attrib a = getAttrib(index);
+        if (a.clientPointer != null && !a.enabled) {
+            clientSideEnabledCount++;
+        }
+        a.enabled = true;
+    }
+
+    public static void disableAttribute(int index) {
+        if (index < 0 || index >= MAX_ATTRIBS) return;
+        final Attrib a = getAttrib(index);
+        if (a.clientPointer != null && a.enabled) {
+            clientSideEnabledCount--;
+        }
+        a.enabled = false;
+    }
+
+    // Lazily allocate each attrib. Most VAOs don't even have 4 attribs, let alone 16.
+    private static Attrib getAttrib(int index) {
+        Attrib a = currentAttribs[index];
+        if (a == null) {
+            a = new Attrib();
+            currentAttribs[index] = a;
+        }
+        return a;
+    }
+
+    public static boolean isClientSideAttrib(int index) {
+        final Attrib attrib = currentAttribs[index];
+        return attrib != null && attrib.isClientSide();
+    }
+
+    public static int getAttribEffectiveStride(int index) {
+        final Attrib attrib = currentAttribs[index];
+        return attrib != null ? attrib.effectiveStride() : 0;
+    }
+
+    public static long getAttribOffset(int index) {
+        final Attrib attrib = currentAttribs[index];
+        return attrib != null ? attrib.offset : 0;
+    }
+
+    public static int getAttribVBO(int index) {
+        final Attrib attrib = currentAttribs[index];
+        return attrib != null ? attrib.vboId : 0;
+    }
+
+    public static @Nullable Attrib get(int index) {
+        return currentAttribs[index];
+    }
+
+
+
+    /**
+     * Returns true if any currently enabled vertex attribute was registered without a VBO
+     * (i.e. as a client-side pointer). In core profile, such attribs are treated as null
+     * offsets into a non-existent buffer, causing a native crash at draw time.
+     */
+    public static boolean hasAnyClientSideEnabledAttrib() {
+        return clientSideEnabledCount > 0;
+    }
+
+    /**
+     * If any enabled vertex attribute uses a client-side pointer (no VBO), upload all such
+     * attribs into a shared stream VBO so the draw succeeds under core profile.
+     */
+    private static int clientArraysVBO = 0;
+    private static int clientArraysVBOCapacity = 0;
+    private static final int[] clientArraysVBOOffsets = new int[VAOManager.MAX_ATTRIBS];
+
+    public static void uploadClientArraysToVBO() {
+        int totalBytes = 0;
+        for (int i = 0; i < VAOManager.MAX_ATTRIBS; i++) {
+            clientArraysVBOOffsets[i] = -1;
+            final VAOManager.Attrib a = VAOManager.get(i);
+            if (a == null || !a.enabled || a.clientPointer == null) continue;
+            clientArraysVBOOffsets[i] = totalBytes;
+            totalBytes += a.clientPointer.remaining();
+        }
+        if (totalBytes == 0) return;
+
+        if (clientArraysVBO == 0) {
+            clientArraysVBO = RENDER_BACKEND.genBuffers();
+        }
+
+        final int savedVBO = GLStateManager.getBoundVBO();
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, clientArraysVBO);
+
+        if (totalBytes > clientArraysVBOCapacity) {
+            int newCap = Math.max(4096, clientArraysVBOCapacity);
+            while (newCap < totalBytes) newCap *= 2;
+            clientArraysVBOCapacity = newCap;
+        }
+        RENDER_BACKEND.bufferData(GL15.GL_ARRAY_BUFFER, clientArraysVBOCapacity, GL15.GL_STREAM_DRAW);
+
+        for (int i = 0; i < VAOManager.MAX_ATTRIBS; i++) {
+            if (clientArraysVBOOffsets[i] < 0) continue;
+            final VAOManager.Attrib a = VAOManager.get(i);
+            RENDER_BACKEND.bufferSubData(GL15.GL_ARRAY_BUFFER, clientArraysVBOOffsets[i], a.clientPointer.duplicate());
+            RENDER_BACKEND.vertexAttribPointer(i, a.size, a.type, a.normalized, a.stride, (long) clientArraysVBOOffsets[i]);
+        }
+
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, savedVBO);
+    }
+
+
+    public static final class Attrib {
+        public boolean enabled;
+        public int size;
+        public int type;
+        public boolean normalized;
+        public int stride;
+        public long offset;
+        public int vboId;
+        public ByteBuffer clientPointer;
+        public boolean genericPointer;
+
+        public boolean isClientSide() {
+            return enabled && clientPointer != null;
+        }
+
+        public void reset() {
+            enabled = false;
+            size = 0;
+            type = 0;
+            normalized = false;
+            stride = 0;
+            offset = 0;
+            vboId = 0;
+            clientPointer = null;
+            genericPointer = false;
+        }
+
+        public int effectiveStride() {
+            return (stride != 0) ? stride : size * typeSizeBytes();
+        }
+
+        public int typeSizeBytes() {
+            return glTypeSizeBytes(type);
+        }
+
+        public static int glTypeSizeBytes(int glType) {
+            return switch (glType) {
+                case GL11.GL_FLOAT, GL11.GL_INT, GL11.GL_UNSIGNED_INT -> 4;
+                case GL11.GL_DOUBLE -> 8;
+                case GL11.GL_SHORT, GL11.GL_UNSIGNED_SHORT -> 2;
+                case GL11.GL_BYTE, GL11.GL_UNSIGNED_BYTE -> 1;
+                default -> 4;
+            };
+        }
+
+        public float readComponent(ByteBuffer buf, int base, int component) {
+            return readComponent(type, normalized, buf, base, component);
+        }
+
+        public static float readComponent(int type, boolean normalized, ByteBuffer buf, int base, int component) {
+            return switch (type) {
+                case GL11.GL_FLOAT -> buf.getFloat(base + component * 4);
+                case GL11.GL_DOUBLE -> (float) buf.getDouble(base + component * 8);
+                case GL11.GL_INT -> {
+                    final int v = buf.getInt(base + component * 4);
+                    yield normalized ? v / (float) Integer.MAX_VALUE : (float) v;
+                }
+                case GL11.GL_UNSIGNED_INT -> {
+                    final int v = buf.getInt(base + component * 4);
+                    yield normalized ? (v & 0xFFFFFFFFL) / (float) 0xFFFFFFFFL : (float) (v & 0xFFFFFFFFL);
+                }
+                case GL11.GL_SHORT -> {
+                    final short v = buf.getShort(base + component * 2);
+                    yield normalized ? v / (float) Short.MAX_VALUE : (float) v;
+                }
+                case GL11.GL_UNSIGNED_SHORT -> {
+                    final int v = buf.getShort(base + component * 2) & 0xFFFF;
+                    yield normalized ? v / (float) 0xFFFF : (float) v;
+                }
+                case GL11.GL_BYTE -> {
+                    final byte v = buf.get(base + component);
+                    yield normalized ? v / 127.0f : (float) v;
+                }
+                case GL11.GL_UNSIGNED_BYTE -> {
+                    final int v = buf.get(base + component) & 0xFF;
+                    yield normalized ? v / 255.0f : (float) v;
+                }
+                default -> 0.0f;
+            };
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/VertexKey.java

@@ -0,0 +1,263 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.MatrixHelper;
+import com.gtnewhorizons.angelica.glsm.DisplayListManager;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.states.TexGenState;
+import com.gtnewhorizons.angelica.glsm.states.TextureUnitArray;
+import org.joml.Matrix4f;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL12;
+
+/**
+ * Compact key capturing the vertex shader permutation axes for FFP emulation.
+ * Packed into a single long for fast hash/compare.
+ *
+ * Per-unit fields are 4-bit base-indexed: bit (BASE + i) for unit i in [0..3].
+ * Unit 1 is the lightmap; texcoord enable for unit 1 also gates the lightmap-specific code paths.
+ */
+public final class VertexKey {
+
+    public static final int MAX_UNITS = 4;
+
+    private final long packed;
+
+    private static final int BIT_LIGHTING            = 0;
+    private static final int BIT_LIGHT0              = 1;
+    private static final int BIT_LIGHT1              = 2;
+    private static final int BIT_LIGHT0_DIR          = 3;
+    private static final int BIT_LIGHT1_DIR          = 4;
+    private static final int BIT_COLOR_MATERIAL      = 5;
+    private static final int BIT_SEPARATE_SPECULAR   = 6;
+    private static final int BIT_FOG                 = 7;
+    private static final int BIT_FOG_DIST_MODE       = 8;  // 2 bits: 8-9
+    private static final int BIT_NORMALIZE           = 10;
+    private static final int BIT_RESCALE_NORMAL      = 11;
+    // Per-unit texcoord enable: bits 12-15 (unit 0..3). Unit 1 doubles as the lightmap flag.
+    private static final int BIT_UNIT_TEX_BASE       = 12;
+    private static final int BIT_HAS_VERTEX_COLOR    = 16;
+    private static final int BIT_HAS_VERTEX_NORMAL   = 17;
+    private static final int BIT_HAS_VERTEX_TEX      = 18;
+    private static final int BIT_HAS_VERTEX_LIGHTMAP = 19;
+    private static final int BIT_COLOR_MAT_MODE      = 20;  // 3 bits: 20-22
+    // TexGen modes (unit 0 only, for now): 3 bits each (0=NONE, 1=OBJ_LINEAR, 2=EYE_LINEAR).
+    private static final int BIT_TEXGEN_S            = 23;  // 3 bits: 23-25
+    private static final int BIT_TEXGEN_T            = 26;  // 3 bits: 26-28
+    private static final int BIT_TEXGEN_R            = 29;  // 3 bits: 29-31
+    private static final int BIT_TEXGEN_Q            = 32;  // 3 bits: 32-34
+    private static final int BIT_CLIP_PLANES         = 35;
+    private static final int BIT_WIDE_LINE           = 36;
+    // Per-unit texmat enable: bits 37-40 (unit 0..3). Unit 1 is the lightmap matrix.
+    private static final int BIT_UNIT_TEXMAT_BASE    = 37;
+    private static final int BIT_UNIT23_UV_FROM_UNIT0 = 41;
+
+    public static final int TG_NONE                  = 0;
+    public static final int TG_OBJ_LINEAR            = 1;
+    public static final int TG_EYE_LINEAR            = 2;
+
+    public static final int CM_AMBIENT               = 0;
+    public static final int CM_DIFFUSE               = 1;
+    public static final int CM_SPECULAR              = 2;
+    public static final int CM_EMISSION              = 3;
+    public static final int CM_AMBIENT_AND_DIFFUSE   = 4;
+
+    private VertexKey(long packed) {
+        this.packed = packed;
+    }
+
+    public long pack() { return packed; }
+
+    public boolean lightingEnabled()       { return bit(BIT_LIGHTING); }
+    public boolean light0Enabled()         { return bit(BIT_LIGHT0); }
+    public boolean light1Enabled()         { return bit(BIT_LIGHT1); }
+    public boolean light0Directional()     { return bit(BIT_LIGHT0_DIR); }
+    public boolean light1Directional()     { return bit(BIT_LIGHT1_DIR); }
+    public boolean colorMaterialEnabled()  { return bit(BIT_COLOR_MATERIAL); }
+    public boolean separateSpecular()      { return bit(BIT_SEPARATE_SPECULAR); }
+    public boolean fogEnabled()            { return bit(BIT_FOG); }
+    public int fogDistanceMode()           { return (int)((packed >> BIT_FOG_DIST_MODE) & 0x3); }
+    public boolean normalizeEnabled()      { return bit(BIT_NORMALIZE); }
+    public boolean rescaleNormalsEnabled() { return bit(BIT_RESCALE_NORMAL); }
+    public boolean unitTexCoordEnabled(int unit) { return bit(BIT_UNIT_TEX_BASE + unit); }
+    public boolean unitTexMatEnabled(int unit)   { return bit(BIT_UNIT_TEXMAT_BASE + unit); }
+    public boolean anyUnitTexCoordEnabled() { return ((packed >> BIT_UNIT_TEX_BASE) & 0xF) != 0; }
+    public boolean lightmapEnabled()       { return unitTexCoordEnabled(1); }
+    public boolean hasVertexColor()        { return bit(BIT_HAS_VERTEX_COLOR); }
+    public boolean hasVertexNormal()       { return bit(BIT_HAS_VERTEX_NORMAL); }
+    public boolean hasVertexTexCoord()     { return bit(BIT_HAS_VERTEX_TEX); }
+    public boolean hasVertexLightmap()    { return bit(BIT_HAS_VERTEX_LIGHTMAP); }
+    public boolean unit23UvFromUnit0()     { return bit(BIT_UNIT23_UV_FROM_UNIT0); }
+    /** Color material mode (CM_AMBIENT, CM_DIFFUSE, CM_SPECULAR, CM_EMISSION, CM_AMBIENT_AND_DIFFUSE). Only meaningful when colorMaterialEnabled(). */
+    public int colorMaterialMode()        { return (int)((packed >> BIT_COLOR_MAT_MODE) & 0x7); }
+
+    /** TexGen mode for S coordinate (TG_NONE, TG_OBJ_LINEAR, TG_EYE_LINEAR). Unit 0 only; see TODO in packFromState. */
+    public int texGenModeS()              { return (int)((packed >> BIT_TEXGEN_S) & 0x7); }
+    public int texGenModeT()              { return (int)((packed >> BIT_TEXGEN_T) & 0x7); }
+    public int texGenModeR()              { return (int)((packed >> BIT_TEXGEN_R) & 0x7); }
+    public int texGenModeQ()              { return (int)((packed >> BIT_TEXGEN_Q) & 0x7); }
+    public boolean texGenEnabled()        { return texGenModeS() != TG_NONE || texGenModeT() != TG_NONE || texGenModeR() != TG_NONE || texGenModeQ() != TG_NONE; }
+    public boolean clipPlanesEnabled()    { return bit(BIT_CLIP_PLANES); }
+    public boolean wideLineEmulation()   { return bit(BIT_WIDE_LINE); }
+
+    public boolean cmReplacesAmbient()    { final int m = colorMaterialMode(); return m == CM_AMBIENT || m == CM_AMBIENT_AND_DIFFUSE; }
+    public boolean cmReplacesDiffuse()    { final int m = colorMaterialMode(); return m == CM_DIFFUSE || m == CM_AMBIENT_AND_DIFFUSE; }
+    public boolean cmReplacesSpecular()   { return colorMaterialMode() == CM_SPECULAR; }
+    public boolean cmReplacesEmission()   { return colorMaterialMode() == CM_EMISSION; }
+
+    private boolean bit(int pos) { return ((packed >> pos) & 1) != 0; }
+
+    static int encodeTexGenMode(int glMode) {
+        return switch (glMode) {
+            case GL11.GL_OBJECT_LINEAR -> TG_OBJ_LINEAR;
+            case GL11.GL_EYE_LINEAR -> TG_EYE_LINEAR;
+            default -> TG_NONE;
+        };
+    }
+
+    static int encodeColorMaterialMode(int glMode) {
+        return switch (glMode) {
+            case GL11.GL_AMBIENT -> CM_AMBIENT;
+            case GL11.GL_DIFFUSE -> CM_DIFFUSE;
+            case GL11.GL_SPECULAR -> CM_SPECULAR;
+            case GL11.GL_EMISSION -> CM_EMISSION;
+            case GL11.GL_AMBIENT_AND_DIFFUSE -> CM_AMBIENT_AND_DIFFUSE;
+            default -> CM_AMBIENT_AND_DIFFUSE;
+        };
+    }
+
+    public static long packFromState(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap, int fragUnitMask) {
+        long bits = 0;
+
+        final boolean lighting = GLStateManager.getLightingState().isEnabled();
+        if (lighting) {
+            bits |= (1L << BIT_LIGHTING);
+
+            if (GLStateManager.getLightStates()[0].isEnabled()) {
+                bits |= (1L << BIT_LIGHT0);
+                // position.w == 0 means directional
+                if (GLStateManager.getLightDataStates()[0].position.w == 0.0f) {
+                    bits |= (1L << BIT_LIGHT0_DIR);
+                }
+            }
+            if (GLStateManager.getLightStates()[1].isEnabled()) {
+                bits |= (1L << BIT_LIGHT1);
+                if (GLStateManager.getLightDataStates()[1].position.w == 0.0f) {
+                    bits |= (1L << BIT_LIGHT1_DIR);
+                }
+            }
+
+            if (GLStateManager.getColorMaterial().isEnabled()) {
+                bits |= (1L << BIT_COLOR_MATERIAL);
+                final int cmMode = encodeColorMaterialMode(GLStateManager.getColorMaterialParameter().getValue());
+                bits |= ((long) cmMode & 0x7) << BIT_COLOR_MAT_MODE;
+            }
+
+            if (GLStateManager.getLightModel().colorControl == GL12.GL_SEPARATE_SPECULAR_COLOR) {
+                bits |= (1L << BIT_SEPARATE_SPECULAR);
+            }
+        }
+
+        if (GLStateManager.getFogMode().isEnabled()) {
+            bits |= (1L << BIT_FOG);
+            final int fogDistMode = GLStateManager.getFogState().getFogDistanceMode();
+            bits |= ((long) fogDistMode & 0x3) << BIT_FOG_DIST_MODE;
+        }
+
+        if (GLStateManager.getNormalizeState().isEnabled()) {
+            bits |= (1L << BIT_NORMALIZE);
+        }
+        if (GLStateManager.getRescaleNormalState().isEnabled()) {
+            bits |= (1L << BIT_RESCALE_NORMAL);
+        }
+
+        final TextureUnitArray texUnit = GLStateManager.getTextures();
+        for (int i = 0; i < MAX_UNITS; i++) {
+            if ((fragUnitMask & (1 << i)) != 0) {
+                bits |= (1L << (BIT_UNIT_TEX_BASE + i));
+            }
+            if (!MatrixHelper.isIdentity(texUnit.getTextureUnitMatrix(i))) {
+                bits |= (1L << (BIT_UNIT_TEXMAT_BASE + i));
+            }
+        }
+
+        // TexGen (unit 0 only) - per-coordinate mode if enabled.
+        // TODO: per-unit texgen for units 2/3. Deferred - no MC code path uses glTexGen on those.
+        final TexGenState tg = texUnit.getTexGenState(0);
+        boolean anyTexGen = false;
+        if (texUnit.getTexGenSStates(0).isEnabled() && tg.getMode(GL11.GL_S) != 0) {
+            final int m = encodeTexGenMode(tg.getMode(GL11.GL_S));
+            bits |= ((long) m & 0x7) << BIT_TEXGEN_S;
+            if (m != TG_NONE) anyTexGen = true;
+        }
+        if (texUnit.getTexGenTStates(0).isEnabled() && tg.getMode(GL11.GL_T) != 0) {
+            final int m = encodeTexGenMode(tg.getMode(GL11.GL_T));
+            bits |= ((long) m & 0x7) << BIT_TEXGEN_T;
+            if (m != TG_NONE) anyTexGen = true;
+        }
+        if (texUnit.getTexGenRStates(0).isEnabled() && tg.getMode(GL11.GL_R) != 0) {
+            final int m = encodeTexGenMode(tg.getMode(GL11.GL_R));
+            bits |= ((long) m & 0x7) << BIT_TEXGEN_R;
+            if (m != TG_NONE) anyTexGen = true;
+        }
+        if (texUnit.getTexGenQStates(0).isEnabled() && tg.getMode(GL11.GL_Q) != 0) {
+            final int m = encodeTexGenMode(tg.getMode(GL11.GL_Q));
+            bits |= ((long) m & 0x7) << BIT_TEXGEN_Q;
+            if (m != TG_NONE) anyTexGen = true;
+        }
+        // Force unit-0 texture matrix on when texgen is active (end portal pattern always uses it).
+        if (anyTexGen) {
+            bits |= (1L << BIT_UNIT_TEXMAT_BASE);
+        }
+
+        // Vertex format flags
+        if (hasColor) bits |= (1L << BIT_HAS_VERTEX_COLOR);
+        if (hasNormal) bits |= (1L << BIT_HAS_VERTEX_NORMAL);
+        if (hasTexCoord) bits |= (1L << BIT_HAS_VERTEX_TEX);
+        if (hasLightmap) bits |= (1L << BIT_HAS_VERTEX_LIGHTMAP);
+
+        if (GLStateManager.consumeUnit23TexCoordSetDuringDraw() && hasTexCoord) {
+            bits |= (1L << BIT_UNIT23_UV_FROM_UNIT0);
+        }
+
+        if (GLStateManager.anyClipPlaneEnabled()) {
+            bits |= (1L << BIT_CLIP_PLANES);
+        }
+
+        if (GLStateManager.wideLineEmulationActive) {
+            bits |= (1L << BIT_WIDE_LINE);
+        }
+
+        return bits;
+    }
+
+    public static VertexKey fromState(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap, int fragUnitMask) {
+        return new VertexKey(packFromState(hasColor, hasNormal, hasTexCoord, hasLightmap, fragUnitMask));
+    }
+
+    static VertexKey fromPacked(long packed) {
+        return new VertexKey(packed);
+    }
+
+    @Override
+    public int hashCode() {
+        return Long.hashCode(packed);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (!(obj instanceof VertexKey other)) return false;
+        return packed == other.packed;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("FFPVertexKey[0x%011X: lit=%b l0=%b l1=%b cm=%b fog=%b tex=%d%d%d%d texmat=%d%d%d%d col=%b nrm=%b vtex=%b vlm=%b tg=%d/%d/%d/%d clip=%b wline=%b]",
+            packed, lightingEnabled(), light0Enabled(), light1Enabled(),
+            colorMaterialEnabled(), fogEnabled(),
+            unitTexCoordEnabled(0)?1:0, unitTexCoordEnabled(1)?1:0, unitTexCoordEnabled(2)?1:0, unitTexCoordEnabled(3)?1:0,
+            unitTexMatEnabled(0)?1:0, unitTexMatEnabled(1)?1:0, unitTexMatEnabled(2)?1:0, unitTexMatEnabled(3)?1:0,
+            hasVertexColor(), hasVertexNormal(), hasVertexTexCoord(), hasVertexLightmap(),
+            texGenModeS(), texGenModeT(), texGenModeR(), texGenModeQ(), clipPlanesEnabled(), wideLineEmulation());
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/VertexShaderGenerator.java

@@ -0,0 +1,434 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement;
+
+/**
+ * Generates GLSL 330 core vertex shaders for FFP emulation.
+ * Follows Mesa's ffvertex_prog.c build order.
+ *
+ * Attribute locations are sourced from {@link VertexFormatElement.Usage} to stay in sync with GTNHLib's vertex format setup.
+ */
+public final class VertexShaderGenerator {
+
+    private VertexShaderGenerator() {}
+
+    public static String generate(VertexKey key) {
+        final StringBuilder sb = new StringBuilder(2048);
+        sb.append("#version 330 core\n\n");
+
+        emitAttributes(sb, key);
+        emitUniforms(sb, key);
+        emitOutputs(sb, key);
+
+        sb.append("void main() {\n");
+        emitPositionTransform(sb, key);
+        if (key.lightingEnabled()) {
+            emitNormalTransform(sb, key);
+            emitLighting(sb, key);
+        } else {
+            emitColorPassthrough(sb, key);
+        }
+        emitTexCoordPassthrough(sb, key);
+        if (key.fogEnabled()) {
+            emitFogDistance(sb, key);
+        }
+        if (key.clipPlanesEnabled()) {
+            emitClipDistances(sb);
+        }
+        sb.append("}\n");
+
+        String source = sb.toString();
+        if (key.wideLineEmulation()) {
+            source = source.replace("v_SpecularColor", "v_SpecularColor_gs")
+                           .replace("v_TexCoord0", "v_TexCoord0_gs")
+                           .replace("v_TexCoord1", "v_TexCoord1_gs")
+                           .replace("v_TexCoord2", "v_TexCoord2_gs")
+                           .replace("v_TexCoord3", "v_TexCoord3_gs")
+                           .replace("v_FogCoord", "v_FogCoord_gs")
+                           .replace("v_Color", "v_Color_gs");
+        }
+        return source;
+    }
+
+    private static void emitAttributes(StringBuilder sb, VertexKey key) {
+        sb.append("// Vertex attributes\n");
+        sb.append("layout(location = ").append(VertexFormatElement.Usage.POSITION.getAttributeLocation()).append(") in vec3 a_Position;\n");
+        if (key.hasVertexColor()) {
+            sb.append("layout(location = ").append(VertexFormatElement.Usage.COLOR.getAttributeLocation()).append(") in vec4 a_Color;\n");
+        }
+        if (key.hasVertexTexCoord()) {
+            sb.append("layout(location = ").append(VertexFormatElement.Usage.PRIMARY_UV.getAttributeLocation()).append(") in vec2 a_TexCoord0;\n");
+        }
+        if (key.hasVertexLightmap()) {
+            sb.append("layout(location = ").append(VertexFormatElement.Usage.SECONDARY_UV.getAttributeLocation()).append(") in vec2 a_TexCoord1;\n");
+        }
+        if (key.hasVertexNormal()) {
+            sb.append("layout(location = ").append(VertexFormatElement.Usage.NORMAL.getAttributeLocation()).append(") in vec3 a_Normal;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitUniforms(StringBuilder sb, VertexKey key) {
+        sb.append("// Matrices\n");
+        sb.append("uniform mat4 u_ModelViewMatrix;\n");
+        sb.append("uniform mat4 u_ProjectionMatrix;\n");
+        sb.append("uniform mat4 u_MVPMatrix;\n");
+
+        if (key.lightingEnabled()) {
+            sb.append("uniform mat3 u_NormalMatrix;\n");
+        }
+
+        for (int i = 0; i < VertexKey.MAX_UNITS; i++) {
+            if (i == 1) continue;
+            if (key.unitTexMatEnabled(i)) {
+                sb.append("uniform mat4 u_TextureMatrix").append(i).append(";\n");
+            }
+        }
+
+        // TexGen plane uniforms (unit 0 only - TODO: per-unit)
+        if (key.texGenModeS() == VertexKey.TG_OBJ_LINEAR) sb.append("uniform vec4 u_TexGenObjPlaneS;\n");
+        if (key.texGenModeS() == VertexKey.TG_EYE_LINEAR) sb.append("uniform vec4 u_TexGenEyePlaneS;\n");
+        if (key.texGenModeT() == VertexKey.TG_OBJ_LINEAR) sb.append("uniform vec4 u_TexGenObjPlaneT;\n");
+        if (key.texGenModeT() == VertexKey.TG_EYE_LINEAR) sb.append("uniform vec4 u_TexGenEyePlaneT;\n");
+        if (key.texGenModeR() == VertexKey.TG_OBJ_LINEAR) sb.append("uniform vec4 u_TexGenObjPlaneR;\n");
+        if (key.texGenModeR() == VertexKey.TG_EYE_LINEAR) sb.append("uniform vec4 u_TexGenEyePlaneR;\n");
+        if (key.texGenModeQ() == VertexKey.TG_OBJ_LINEAR) sb.append("uniform vec4 u_TexGenObjPlaneQ;\n");
+        if (key.texGenModeQ() == VertexKey.TG_EYE_LINEAR) sb.append("uniform vec4 u_TexGenEyePlaneQ;\n");
+
+        if (!key.hasVertexNormal() && key.lightingEnabled()) {
+            sb.append("uniform vec3 u_CurrentNormal;\n");
+        }
+
+        if (!key.hasVertexColor()) {
+            sb.append("uniform vec4 u_CurrentColor;\n");
+        }
+
+        if (key.unitTexCoordEnabled(0) && !key.hasVertexTexCoord()) {
+            sb.append("uniform vec4 u_CurrentTexCoord0;\n");
+        }
+        if (key.unitTexCoordEnabled(2) && !key.unit23UvFromUnit0()) sb.append("uniform vec4 u_CurrentTexCoord2;\n");
+        if (key.unitTexCoordEnabled(3) && !key.unit23UvFromUnit0()) sb.append("uniform vec4 u_CurrentTexCoord3;\n");
+
+        if (key.lightmapEnabled() && !key.hasVertexLightmap()) {
+            sb.append("uniform vec2 u_CurrentLightmapCoord;\n");
+        }
+
+        if (key.lightmapEnabled()) {
+            sb.append("uniform mat4 u_LightmapTextureMatrix;\n");
+        }
+
+        if (key.lightingEnabled()) {
+            emitLightingUniforms(sb, key);
+        }
+
+        if (key.lightingEnabled() && (key.normalizeEnabled() || key.rescaleNormalsEnabled())) {
+            // normalize is done in shader; rescale uses normalScale
+            if (key.rescaleNormalsEnabled() && !key.normalizeEnabled()) {
+                sb.append("uniform float u_NormalScale;\n");
+            }
+        }
+
+        if (key.clipPlanesEnabled()) {
+            sb.append("uniform vec4 u_ClipPlane[8];\n");
+        }
+
+        sb.append('\n');
+    }
+
+    private static void emitLightingUniforms(StringBuilder sb, VertexKey key) {
+        sb.append("\n// Lighting\n");
+
+        if (key.colorMaterialEnabled()) {
+            // When color material is active, we can't pre-compute light products so we upload raw light and material values
+            sb.append("uniform vec4 u_LightModelAmbient;\n");
+            sb.append("uniform vec4 u_MaterialEmission;\n");
+            sb.append("uniform vec4 u_MaterialAmbient;\n");
+            sb.append("uniform vec4 u_MaterialDiffuse;\n");
+            sb.append("uniform vec4 u_MaterialSpecular;\n");
+            sb.append("uniform float u_MaterialShininess;\n");
+
+            if (key.light0Enabled()) {
+                sb.append("uniform vec4 u_Light0Ambient;\n");
+                sb.append("uniform vec4 u_Light0Diffuse;\n");
+                sb.append("uniform vec4 u_Light0Specular;\n");
+                sb.append("uniform vec4 u_Light0Position;\n");
+            }
+            if (key.light1Enabled()) {
+                sb.append("uniform vec4 u_Light1Ambient;\n");
+                sb.append("uniform vec4 u_Light1Diffuse;\n");
+                sb.append("uniform vec4 u_Light1Specular;\n");
+                sb.append("uniform vec4 u_Light1Position;\n");
+            }
+        } else {
+            // Pre-computed: sceneColor + lightProducts
+            sb.append("uniform vec4 u_SceneColor;\n");
+
+            if (key.light0Enabled()) {
+                sb.append("uniform vec4 u_Light0Position;\n");
+                sb.append("uniform vec3 u_LightProd0Ambient;\n");
+                sb.append("uniform vec3 u_LightProd0Diffuse;\n");
+                sb.append("uniform vec3 u_LightProd0Specular;\n");
+            }
+            if (key.light1Enabled()) {
+                sb.append("uniform vec4 u_Light1Position;\n");
+                sb.append("uniform vec3 u_LightProd1Ambient;\n");
+                sb.append("uniform vec3 u_LightProd1Diffuse;\n");
+                sb.append("uniform vec3 u_LightProd1Specular;\n");
+            }
+            sb.append("uniform float u_MaterialShininess;\n");
+        }
+    }
+
+    private static void emitOutputs(StringBuilder sb, VertexKey key) {
+        sb.append("// Outputs\n");
+        sb.append("out vec4 v_Color;\n");
+        if (key.separateSpecular()) {
+            sb.append("out vec3 v_SpecularColor;\n");
+        }
+        // Per-unit varying outputs. Each enabled texture unit (and texgen, which targets unit 0) gets its own v_TexCoord<i>.
+        if (key.unitTexCoordEnabled(0) || key.texGenEnabled()) {
+            sb.append("out vec4 v_TexCoord0;\n");
+        }
+        if (key.lightmapEnabled()) {
+            sb.append("out vec4 v_TexCoord1;\n");
+        }
+        if (key.unitTexCoordEnabled(2)) sb.append("out vec4 v_TexCoord2;\n");
+        if (key.unitTexCoordEnabled(3)) sb.append("out vec4 v_TexCoord3;\n");
+        if (key.fogEnabled()) {
+            sb.append("out float v_FogCoord;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitPositionTransform(StringBuilder sb, VertexKey key) {
+        sb.append("  // Position transform\n");
+        sb.append("  vec4 pos4 = vec4(a_Position, 1.0);\n");
+        sb.append("  gl_Position = u_MVPMatrix * pos4;\n");
+
+        // Eye position needed for lighting, fog, EYE_LINEAR texgen, and clip planes
+        if (key.lightingEnabled() || key.fogEnabled() || texGenNeedsEyePos(key) || key.clipPlanesEnabled()) {
+            sb.append("  vec4 eyePos = u_ModelViewMatrix * pos4;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitNormalTransform(StringBuilder sb, VertexKey key) {
+        sb.append("  // Normal transform\n");
+        if (key.hasVertexNormal()) {
+            sb.append("  vec3 normal = u_NormalMatrix * a_Normal;\n");
+        } else {
+            sb.append("  vec3 normal = u_NormalMatrix * u_CurrentNormal;\n");
+        }
+
+        if (key.normalizeEnabled()) {
+            sb.append("  normal = normalize(normal);\n");
+        } else if (key.rescaleNormalsEnabled()) {
+            sb.append("  normal *= u_NormalScale;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitLighting(StringBuilder sb, VertexKey key) {
+        sb.append("  // Gouraud lighting\n");
+
+        if (key.colorMaterialEnabled()) {
+            // Color material: vertex color replaces specific material properties per glColorMaterial mode (Mesa ffvertex_prog.c get_material() bitmask approach)
+            sb.append("  vec4 matColor = ");
+            sb.append(key.hasVertexColor() ? "a_Color" : "u_CurrentColor");
+            sb.append(";\n");
+
+            // Emission source: vertex color for CM_EMISSION, else material uniform
+            final String emSrc = key.cmReplacesEmission() ? "matColor.rgb" : "u_MaterialEmission.rgb";
+            // Ambient source for scene color: vertex color for CM_AMBIENT / CM_AMBIENT_AND_DIFFUSE
+            final String amSrc = key.cmReplacesAmbient() ? "matColor.rgb" : "u_MaterialAmbient.rgb";
+            sb.append("  vec3 sceneColor = ").append(emSrc).append(" + ").append(amSrc).append(" * u_LightModelAmbient.rgb;\n");
+
+            // Alpha from diffuse source (per GL spec)
+            sb.append("  float outAlpha = ").append(key.cmReplacesDiffuse() ? "matColor.a" : "u_MaterialDiffuse.a").append(";\n");
+        } else {
+            // Pre-computed scene color
+            sb.append("  vec3 sceneColor = u_SceneColor.rgb;\n");
+            sb.append("  float outAlpha = u_SceneColor.a;\n");
+        }
+
+        sb.append("  vec3 color0 = sceneColor;\n");
+        if (key.separateSpecular()) {
+            sb.append("  vec3 specAccum = vec3(0.0);\n");
+        }
+
+        // Per-light accumulation
+        if (key.light0Enabled()) {
+            emitLightContribution(sb, key, 0);
+        }
+        if (key.light1Enabled()) {
+            emitLightContribution(sb, key, 1);
+        }
+
+        sb.append("  v_Color = vec4(clamp(color0, 0.0, 1.0), outAlpha);\n");
+        if (key.separateSpecular()) {
+            sb.append("  v_SpecularColor = clamp(specAccum, 0.0, 1.0);\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitLightContribution(StringBuilder sb, VertexKey key, int lightIndex) {
+        final String li = String.valueOf(lightIndex);
+        final boolean directional = (lightIndex == 0) ? key.light0Directional() : key.light1Directional();
+        final String posUniform = "u_Light" + li + "Position";
+
+        sb.append("  { // Light ").append(li).append('\n');
+
+        // Light vector
+        if (directional) {
+            // Directional: position is already normalized direction
+            sb.append("    vec3 VPpli = normalize(").append(posUniform).append(".xyz);\n");
+        } else {
+            // Positional light
+            sb.append("    vec3 VPpli = ").append(posUniform).append(".xyz - eyePos.xyz;\n");
+            sb.append("    VPpli = normalize(VPpli);\n");
+        }
+
+        // Dot products
+        sb.append("    float NdotVP = max(dot(normal, VPpli), 0.0);\n");
+
+        // Half vector for specular (infinite viewer: H = normalize(L + (0,0,1)))
+        sb.append("    vec3 halfVec = normalize(VPpli + vec3(0.0, 0.0, 1.0));\n");
+        sb.append("    float NdotHV = max(dot(normal, halfVec), 0.0);\n");
+
+        // Specular power
+        sb.append("    float spec = (NdotVP > 0.0 && u_MaterialShininess > 0.0) ? pow(NdotHV, u_MaterialShininess) : 0.0;\n");
+
+        // Accumulate — per-property source depends on color material mode
+        if (key.colorMaterialEnabled()) {
+            final String ambU = "u_Light" + li + "Ambient";
+            final String difU = "u_Light" + li + "Diffuse";
+            final String speU = "u_Light" + li + "Specular";
+            // Ambient product: light.ambient * (vertex color or material)
+            final String ambMat = key.cmReplacesAmbient() ? "matColor.rgb" : "u_MaterialAmbient.rgb";
+            sb.append("    vec3 ambient = ").append(ambU).append(".rgb * ").append(ambMat).append(";\n");
+            // Diffuse product
+            final String difMat = key.cmReplacesDiffuse() ? "matColor.rgb" : "u_MaterialDiffuse.rgb";
+            sb.append("    vec3 diffuse = ").append(difU).append(".rgb * ").append(difMat).append(";\n");
+            // Specular product
+            final String speMat = key.cmReplacesSpecular() ? "matColor.rgb" : "u_MaterialSpecular.rgb";
+            sb.append("    vec3 specular = ").append(speU).append(".rgb * ").append(speMat).append(";\n");
+        } else {
+            sb.append("    vec3 ambient = u_LightProd").append(li).append("Ambient;\n");
+            sb.append("    vec3 diffuse = u_LightProd").append(li).append("Diffuse;\n");
+            sb.append("    vec3 specular = u_LightProd").append(li).append("Specular;\n");
+        }
+
+        sb.append("    color0 += ambient + NdotVP * diffuse;\n");
+        if (key.separateSpecular()) {
+            sb.append("    specAccum += spec * specular;\n");
+        } else {
+            sb.append("    color0 += spec * specular;\n");
+        }
+
+        sb.append("  }\n");
+    }
+
+    private static void emitColorPassthrough(StringBuilder sb, VertexKey key) {
+        sb.append("  // Color passthrough (no lighting)\n");
+        if (key.hasVertexColor()) {
+            sb.append("  v_Color = a_Color;\n");
+        } else {
+            sb.append("  v_Color = u_CurrentColor;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitTexCoordPassthrough(StringBuilder sb, VertexKey key) {
+        if (key.texGenEnabled()) {
+            emitTexGenCoordGeneration(sb, key);
+        } else if (key.unitTexCoordEnabled(0)) {
+            sb.append("  // Texture coordinates - unit 0\n");
+            final String src = key.hasVertexTexCoord()
+                ? "vec4(a_TexCoord0, 0.0, 1.0)"
+                : "u_CurrentTexCoord0";
+            if (key.unitTexMatEnabled(0)) {
+                sb.append("  v_TexCoord0 = u_TextureMatrix0 * ").append(src).append(";\n");
+            } else {
+                sb.append("  v_TexCoord0 = ").append(src).append(";\n");
+            }
+        }
+
+        if (key.lightmapEnabled()) {
+            if (key.hasVertexLightmap()) {
+                sb.append("  v_TexCoord1 = u_LightmapTextureMatrix * vec4(a_TexCoord1, 0.0, 1.0);\n");
+            } else {
+                sb.append("  v_TexCoord1 = u_LightmapTextureMatrix * vec4(u_CurrentLightmapCoord, 0.0, 1.0);\n");
+            }
+        }
+
+        for (int i = 2; i < VertexKey.MAX_UNITS; i++) {
+            if (!key.unitTexCoordEnabled(i)) continue;
+            final String src = key.unit23UvFromUnit0()
+                ? "vec4(a_TexCoord0, 0.0, 1.0)"
+                : "u_CurrentTexCoord" + i;
+            if (!key.unit23UvFromUnit0() && key.unitTexMatEnabled(i)) {
+                sb.append("  v_TexCoord").append(i).append(" = u_TextureMatrix").append(i).append(" * ").append(src).append(";\n");
+            } else {
+                sb.append("  v_TexCoord").append(i).append(" = ").append(src).append(";\n");
+            }
+        }
+    }
+
+    /**
+     * Emit per-coordinate texgen code following Mesa's ffvertex_prog.c build order.
+     * OBJ_LINEAR: dot(pos4, objPlane), EYE_LINEAR: dot(eyePos, eyePlane).
+     * Coordinates without texgen use vertex attrib or default (0,0,0,1).
+     */
+    private static void emitTexGenCoordGeneration(StringBuilder sb, VertexKey key) {
+        sb.append("  // TexGen coordinate generation\n");
+        sb.append("  vec4 texGenCoord = vec4(0.0, 0.0, 0.0, 1.0);\n");
+
+        emitTexGenComponent(sb, key.texGenModeS(), "s", "S", key);
+        emitTexGenComponent(sb, key.texGenModeT(), "t", "T", key);
+        emitTexGenComponent(sb, key.texGenModeR(), "p", "R", key);
+        emitTexGenComponent(sb, key.texGenModeQ(), "q", "Q", key);
+
+        // Always apply texture matrix when texgen is active (forced on in VertexKey)
+        sb.append("  v_TexCoord0 = u_TextureMatrix0 * texGenCoord;\n");
+    }
+
+    private static void emitTexGenComponent(StringBuilder sb, int mode, String swizzle, String coordName, VertexKey key) {
+        switch (mode) {
+            case VertexKey.TG_OBJ_LINEAR ->
+                sb.append("  texGenCoord.").append(swizzle).append(" = dot(pos4, u_TexGenObjPlane").append(coordName).append(");\n");
+            case VertexKey.TG_EYE_LINEAR ->
+                sb.append("  texGenCoord.").append(swizzle).append(" = dot(eyePos, u_TexGenEyePlane").append(coordName).append(");\n");
+            // TG_NONE: keep default (0 for s/t/r, 1 for q) — already set in texGenCoord init
+        }
+    }
+
+    private static boolean texGenNeedsEyePos(VertexKey key) {
+        return key.texGenModeS() == VertexKey.TG_EYE_LINEAR
+            || key.texGenModeT() == VertexKey.TG_EYE_LINEAR
+            || key.texGenModeR() == VertexKey.TG_EYE_LINEAR
+            || key.texGenModeQ() == VertexKey.TG_EYE_LINEAR;
+    }
+
+    private static void emitFogDistance(StringBuilder sb, VertexKey key) {
+        sb.append("  // Fog distance\n");
+        // Mesa ffvertex_prog.c build_fog(): FDM_EYE_RADIAL/EYE_PLANE/EYE_PLANE_ABS
+        final int fogDistMode = key.fogDistanceMode();
+        switch (fogDistMode) {
+            case 0 -> // FDM_EYE_RADIAL: Euclidean distance
+                sb.append("  v_FogCoord = length(eyePos.xyz);\n");
+            case 1 -> // FDM_EYE_PLANE: raw Z (can be negative, clamped by fog factor)
+                sb.append("  v_FogCoord = eyePos.z;\n");
+            case 2 -> // FDM_EYE_PLANE_ABS: absolute Z
+                sb.append("  v_FogCoord = abs(eyePos.z);\n");
+            default ->
+                sb.append("  v_FogCoord = abs(eyePos.z);\n");
+        }
+    }
+
+    private static void emitClipDistances(StringBuilder sb) {
+        sb.append("  // Clip distances\n");
+        for (int i = 0; i < 8; i++) {
+            sb.append("  gl_ClipDistance[").append(i).append("] = dot(u_ClipPlane[").append(i).append("], eyePos);\n");
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/DeferredAlphaHandler.java

@@ -0,0 +1,7 @@
+package com.gtnewhorizons.angelica.glsm.hooks;
+
+public interface DeferredAlphaHandler {
+    boolean isAlphaTestLocked();
+    void deferAlphaTestToggle(boolean enabled);
+    void deferAlphaFunc(int function, float reference);
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/DeferredBlendHandler.java

@@ -0,0 +1,8 @@
+package com.gtnewhorizons.angelica.glsm.hooks;
+
+public interface DeferredBlendHandler {
+    boolean isBlendLocked();
+    void deferBlendModeToggle(boolean enabled);
+    void deferBlendFunc(int srcRgb, int dstRgb, int srcAlpha, int dstAlpha);
+    void flushDeferredBlend();
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/DeferredDepthColorHandler.java

@@ -0,0 +1,7 @@
+package com.gtnewhorizons.angelica.glsm.hooks;
+
+public interface DeferredDepthColorHandler {
+    boolean isDepthColorLocked();
+    void deferDepthEnable(boolean enabled);
+    void deferColorMask(boolean r, boolean g, boolean b, boolean a);
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/GLSMConfig.java

@@ -0,0 +1,12 @@
+package com.gtnewhorizons.angelica.glsm.hooks;
+
+public final class GLSMConfig {
+
+    // Lightmap (replaces OpenGlHelper.lastBrightnessX/Y)
+    public static float lastBrightnessX;
+    public static float lastBrightnessY;
+
+    public static boolean hudCacheOverride;
+
+    private GLSMConfig() {}
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/GLSMHooks.java

@@ -0,0 +1,36 @@
+package com.gtnewhorizons.angelica.glsm.hooks;
+
+import com.gtnewhorizons.angelica.glsm.hooks.events.*;
+import net.minecraftforge.eventbus.api.bus.EventBus;
+
+public final class GLSMHooks {
+
+    public static DeferredBlendHandler blendHandler;
+    public static DeferredAlphaHandler alphaHandler;
+    public static DeferredDepthColorHandler depthColorHandler;
+    public static GlintColorHandler glintColorHandler;
+
+    // EventBus instances
+    public static final EventBus<TextureBindEvent> TEXTURE_BIND = EventBus.create(TextureBindEvent.class);
+    public static final EventBus<TextureDeleteEvent> TEXTURE_DELETE = EventBus.create(TextureDeleteEvent.class);
+    public static final EventBus<TextureUnitStateEvent> TEXTURE_UNIT_STATE = EventBus.create(TextureUnitStateEvent.class);
+    public static final EventBus<ProgramChangeEvent> PROGRAM_CHANGE = EventBus.create(ProgramChangeEvent.class);
+    public static final EventBus<BlendFuncChangeEvent> BLEND_FUNC_CHANGE = EventBus.create(BlendFuncChangeEvent.class);
+    public static final EventBus<FogStateChangeEvent> FOG_STATE_CHANGE = EventBus.create(FogStateChangeEvent.class);
+    public static final EventBus<LightmapCoordsEvent> LIGHTMAP_COORDS = EventBus.create(LightmapCoordsEvent.class);
+    public static final EventBus<AlphaStateChangeEvent> ALPHA_STATE_CHANGE = EventBus.create(AlphaStateChangeEvent.class);
+    public static final EventBus<ShaderColorChangeEvent> SHADER_COLOR_CHANGE = EventBus.create(ShaderColorChangeEvent.class);
+
+    // Reusable event instances
+    public static final TextureBindEvent textureBindEvent = new TextureBindEvent();
+    public static final TextureDeleteEvent textureDeleteEvent = new TextureDeleteEvent();
+    public static final TextureUnitStateEvent textureUnitStateEvent = new TextureUnitStateEvent();
+    public static final ProgramChangeEvent programChangeEvent = new ProgramChangeEvent();
+    public static final BlendFuncChangeEvent blendFuncChangeEvent = new BlendFuncChangeEvent();
+    public static final FogStateChangeEvent fogStateChangeEvent = new FogStateChangeEvent();
+    public static final LightmapCoordsEvent lightmapCoordsEvent = new LightmapCoordsEvent();
+    public static final AlphaStateChangeEvent alphaStateChangeEvent = new AlphaStateChangeEvent();
+    public static final ShaderColorChangeEvent shaderColorChangeEvent = new ShaderColorChangeEvent();
+
+    private GLSMHooks() {}
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/GLSMInitConfig.java

@@ -0,0 +1,103 @@
+package com.gtnewhorizons.angelica.glsm.hooks;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.DirectTessellator;
+import com.gtnewhorizons.angelica.glsm.streaming.StreamingUploader;
+
+import java.util.function.Consumer;
+
+public final class GLSMInitConfig {
+    private final boolean lwjglDebug;
+    private final StreamingUploader.UploadStrategy streamingUploadStrategy;
+    private final Consumer<DirectTessellator> directDrawer;
+    private final Runnable streamingDrawerDestroy;
+    private final int displayWidth;
+    private final int displayHeight;
+    private final Runnable postInitCallback;
+    private final boolean enableDSA;
+    private final boolean noErrorChecks;
+
+    private GLSMInitConfig(Builder builder) {
+        this.lwjglDebug = builder.lwjglDebug;
+        this.streamingUploadStrategy = builder.streamingUploadStrategy;
+        this.noErrorChecks = builder.noErrorChecks;
+        this.directDrawer = builder.directDrawer;
+        this.streamingDrawerDestroy = builder.streamingDrawerDestroy;
+        this.displayWidth = builder.displayWidth;
+        this.displayHeight = builder.displayHeight;
+        this.postInitCallback = builder.postInitCallback;
+        this.enableDSA = builder.enableDSA;
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public boolean isLwjglDebug() { return lwjglDebug; }
+    public StreamingUploader.UploadStrategy getStreamingUploadStrategy() { return streamingUploadStrategy; }
+    public Consumer<DirectTessellator> getDirectDrawer() { return directDrawer; }
+    public Runnable getStreamingDrawerDestroy() { return streamingDrawerDestroy; }
+    public int getDisplayWidth() { return displayWidth; }
+    public int getDisplayHeight() { return displayHeight; }
+    public Runnable getPostInitCallback() { return postInitCallback; }
+    public boolean isDSAEnabled() { return enableDSA; }
+    public boolean noErrorChecks() { return noErrorChecks; }
+
+    public static final class Builder {
+        private boolean lwjglDebug = false;
+        private StreamingUploader.UploadStrategy streamingUploadStrategy = StreamingUploader.UploadStrategy.BUFFER_DATA;
+        private Consumer<DirectTessellator> directDrawer = null;
+        private Runnable streamingDrawerDestroy = null;
+        private int displayWidth = 0;
+        private int displayHeight = 0;
+        private Runnable postInitCallback = null;
+        private boolean enableDSA = false;
+        private boolean noErrorChecks;
+
+        private Builder() {}
+
+        public Builder lwjglDebug(boolean lwjglDebug) {
+            this.lwjglDebug = lwjglDebug;
+            return this;
+        }
+
+        public Builder streamingUploadStrategy(StreamingUploader.UploadStrategy strategy) {
+            this.streamingUploadStrategy = strategy;
+            return this;
+        }
+
+        public Builder noErrorChecks(boolean noErrorChecks) {
+            this.noErrorChecks = noErrorChecks;
+            return this;
+        }
+
+        public Builder directDrawer(Consumer<DirectTessellator> directDrawer) {
+            this.directDrawer = directDrawer;
+            return this;
+        }
+
+        public Builder streamingDrawerDestroy(Runnable streamingDrawerDestroy) {
+            this.streamingDrawerDestroy = streamingDrawerDestroy;
+            return this;
+        }
+
+        public Builder displaySize(int width, int height) {
+            this.displayWidth = width;
+            this.displayHeight = height;
+            return this;
+        }
+
+        public Builder postInitCallback(Runnable callback) {
+            this.postInitCallback = callback;
+            return this;
+        }
+
+        public Builder enableDSA(boolean enableDSA) {
+            this.enableDSA = enableDSA;
+            return this;
+        }
+
+        public GLSMInitConfig build() {
+            return new GLSMInitConfig(this);
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/GlintColorHandler.java

@@ -0,0 +1,5 @@
+package com.gtnewhorizons.angelica.glsm.hooks;
+
+public interface GlintColorHandler {
+    void onColorChanged(float red, float green, float blue, float alpha);
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/events/AlphaStateChangeEvent.java

@@ -0,0 +1,9 @@
+package com.gtnewhorizons.angelica.glsm.hooks.events;
+
+import net.minecraftforge.eventbus.api.event.MutableEvent;
+
+/**
+ * AlphaTest changed - Listeners should query GLSM alpha state directly if they care what changed.
+ */
+public final class AlphaStateChangeEvent extends MutableEvent {
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/events/BlendFuncChangeEvent.java

@@ -0,0 +1,10 @@
+package com.gtnewhorizons.angelica.glsm.hooks.events;
+
+import net.minecraftforge.eventbus.api.event.MutableEvent;
+
+public final class BlendFuncChangeEvent extends MutableEvent {
+    public int srcRgb;
+    public int dstRgb;
+    public int srcAlpha;
+    public int dstAlpha;
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/events/FogStateChangeEvent.java

@@ -0,0 +1,6 @@
+package com.gtnewhorizons.angelica.glsm.hooks.events;
+
+import net.minecraftforge.eventbus.api.event.MutableEvent;
+
+/** FogState changed - Listeners should query GLSM fog state directly if they care what changed. */
+public final class FogStateChangeEvent extends MutableEvent {}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/events/LightmapCoordsEvent.java

@@ -0,0 +1,8 @@
+package com.gtnewhorizons.angelica.glsm.hooks.events;
+
+import net.minecraftforge.eventbus.api.event.MutableEvent;
+
+public final class LightmapCoordsEvent extends MutableEvent {
+    public float x;
+    public float y;
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/events/ProgramChangeEvent.java

@@ -0,0 +1,9 @@
+package com.gtnewhorizons.angelica.glsm.hooks.events;
+
+import net.minecraftforge.eventbus.api.event.MutableEvent;
+
+public final class ProgramChangeEvent extends MutableEvent {
+    public int previousProgram;
+    public int newProgram;
+    public boolean postBind;
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/events/ShaderColorChangeEvent.java

@@ -0,0 +1,10 @@
+package com.gtnewhorizons.angelica.glsm.hooks.events;
+
+import net.minecraftforge.eventbus.api.event.MutableEvent;
+
+public final class ShaderColorChangeEvent extends MutableEvent {
+    public float red;
+    public float green;
+    public float blue;
+    public float alpha;
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/events/TextureBindEvent.java

@@ -0,0 +1,7 @@
+package com.gtnewhorizons.angelica.glsm.hooks.events;
+
+import net.minecraftforge.eventbus.api.event.MutableEvent;
+
+public final class TextureBindEvent extends MutableEvent {
+    public int textureId;
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/events/TextureDeleteEvent.java

@@ -0,0 +1,7 @@
+package com.gtnewhorizons.angelica.glsm.hooks.events;
+
+import net.minecraftforge.eventbus.api.event.MutableEvent;
+
+public final class TextureDeleteEvent extends MutableEvent {
+    public int textureId;
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/events/TextureUnitStateEvent.java

@@ -0,0 +1,8 @@
+package com.gtnewhorizons.angelica.glsm.hooks.events;
+
+import net.minecraftforge.eventbus.api.event.MutableEvent;
+
+public final class TextureUnitStateEvent extends MutableEvent {
+    public int unit;
+    public boolean enabled;
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/loading/DependencyVerifier.java

@@ -0,0 +1,32 @@
+package com.gtnewhorizons.angelica.glsm.loading;
+
+import java.util.List;
+
+/**
+ * Verifies required classes/resources are present on the classpath at load time.
+ * Fails fast with a descriptive error message if a dependency is missing.
+ */
+public final class DependencyVerifier {
+
+    /**
+     * A single dependency check: a classpath resource that must exist.
+     * @param resourcePath  Resource path to check (e.g. "/com/example/SomeClass.class")
+     * @param errorMessage  Human-readable error message if missing (include download URL)
+     */
+    public record Check(String resourcePath, String errorMessage) {}
+
+    /**
+     * Verify all checks pass. Throws RuntimeException on first failure.
+     * @param anchor  Class whose classloader to use for resource lookups
+     * @param checks  Dependency checks to run
+     */
+    public static void verify(Class<?> anchor, List<Check> checks) {
+        for (Check check : checks) {
+            if (anchor.getResource(check.resourcePath()) == null) {
+                throw new RuntimeException(check.errorMessage());
+            }
+        }
+    }
+
+    private DependencyVerifier() {}
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/loading/EarlyRedirectorCore.java

@@ -0,0 +1,54 @@
+package com.gtnewhorizons.angelica.glsm.loading;
+
+import com.gtnewhorizons.angelica.glsm.redirect.GLSMRedirector;
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.tree.ClassNode;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public final class EarlyRedirectorCore {
+
+    private final GLSMRedirector core;
+    private final String[] targets;
+    private final String[] exclusions;
+
+    public EarlyRedirectorCore(String... extraExclusions) {
+        this.core = new GLSMRedirector();
+        this.targets = EcosystemNarrowRules.EARLY_REDIRECTOR_TARGETS.clone();
+
+        final List<String> excl = new ArrayList<>(Arrays.asList(core.getCoreExclusions()));
+        if (extraExclusions != null && extraExclusions.length > 0) {
+            Collections.addAll(excl, extraExclusions);
+        }
+        this.exclusions = excl.toArray(new String[0]);
+    }
+
+    public byte[] transform(String transformedName, byte[] basicClass) {
+        if (basicClass == null) return null;
+
+        if (!startsWithAny(transformedName, targets)) return basicClass;
+        if (startsWithAny(transformedName, exclusions)) return basicClass;
+        if (!core.shouldTransform(basicClass)) return basicClass;
+
+        final ClassReader cr = new ClassReader(basicClass);
+        final ClassNode cn = new ClassNode();
+        cr.accept(cn, 0);
+        if (core.transformClassNode(transformedName, cn)) {
+            final ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
+            cn.accept(cw);
+            return cw.toByteArray();
+        }
+        return basicClass;
+    }
+
+    private static boolean startsWithAny(String name, String[] prefixes) {
+        for (String p : prefixes) {
+            if (name.startsWith(p)) return true;
+        }
+        return false;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/loading/EcosystemNarrowRules.java

@@ -0,0 +1,97 @@
+package com.gtnewhorizons.angelica.glsm.loading;
+
+import com.gtnewhorizons.angelica.glsm.loading.TransformerNarrower.NarrowRule;
+
+import java.util.List;
+
+public final class EcosystemNarrowRules {
+
+    public static final List<NarrowRule> ALL = List.of(
+        new NarrowRule("DragonAPI", "Reika.DragonAPI.ASM", List.of(
+            "Reika.DragonAPI.ASM.Patchers",
+            "Reika.DragonAPI.ASM.Profiling",
+            "Reika.DragonAPI.ASM.APIStripper",
+            "Reika.DragonAPI.ASM.ClassReparenter",
+            "Reika.DragonAPI.ASM.DependentMethodStripper",
+            "Reika.DragonAPI.ASM.DragonAPIClassTransformer",
+            "Reika.DragonAPI.ASM.FMLItemBlockPatch",
+            "Reika.DragonAPI.ASM.FluidNamePatch",
+            "Reika.DragonAPI.ASM.InterfaceInjector",
+            "Reika.DragonAPI.ASM.SpecialBiomePlacement",
+            "Reika.DragonAPI.ASM.StructureLootHooks"
+        )),
+
+        new NarrowRule("Xaeros_common", "xaero.common.core", List.of(
+            "xaero.common.core.transformer"
+        )),
+
+        new NarrowRule("Xaeros_map", "xaero.map.core", List.of(
+            "xaero.map.core.transformer"
+        )),
+
+        new NarrowRule("AdvancedLightsabers", "com.fiskmods.lightsabers.asm", List.of(
+            "com.fiskmods.lightsabers.asm.ALLoadingPlugin",
+            "com.fiskmods.lightsabers.asm.ASMHooks",
+            "com.fiskmods.lightsabers.asm.transformers"
+        )),
+
+        new NarrowRule("FiskHeroes", "com.fiskmods.heroes.asm", List.of(
+            "com.fiskmods.heroes.asm.SHLoadingPlugin",
+            "com.fiskmods.heroes.asm.transformers"
+        )),
+
+        new NarrowRule("Ears", "com.unascribed.ears", List.of(
+            "com.unascribed.ears.asm",
+            "com.unascribed.ears.common.agent"
+        )),
+
+        new NarrowRule("FoamFix", "pl.asie.foamfix", List.of(
+            "pl.asie.foamfix.bugfixmod",
+            "pl.asie.foamfix.coremod",
+            "pl.asie.foamfix.forkage",
+            "pl.asie.foamfix.ghostbuster",
+            "pl.asie.foamfix.FoamFixMod",
+            "pl.asie.foamfix.HackyMessageFactoryWrapper",
+            "pl.asie.foamfix.LaunchWrapperRuntimeFix",
+            "pl.asie.foamfix.ProxyClient",
+            "pl.asie.foamfix.ProxyCommon",
+            "pl.asie.foamfix.repack.com.unascribed.ears.asm",
+            "pl.asie.foamfix.repack.com.unascribed.ears.common.agent"
+        )),
+
+        new NarrowRule("Alfheim", "alfheim.common.core.asm.hook", List.of(
+            "alfheim.common.core.asm.hook.AlfheimFieldHookHandler",
+            "alfheim.common.core.asm.hook.AlfheimHPHooks",
+            "alfheim.common.core.asm.hook.Botania18AndUpBackport",
+            "alfheim.common.core.asm.hook.ElementalDamageAdapter",
+            "alfheim.common.core.asm.hook.integration",
+            "alfheim.common.core.asm.hook.extender.FurnaceExtender",
+            "alfheim.common.core.asm.hook.extender.ItemAuraRingExtender",
+            "alfheim.common.core.asm.hook.extender.ItemLensExtender",
+            "alfheim.common.core.asm.hook.extender.ItemTwigWandExtender",
+            "alfheim.common.core.asm.hook.extender.LightRelayExtender",
+            "alfheim.common.core.asm.hook.extender.PureDaisyExtender",
+            "alfheim.common.core.asm.hook.extender.QuartzExtender",
+            "alfheim.common.core.asm.hook.extender.RelicHooks",
+            "alfheim.common.core.asm.hook.extender.SparkExtender",
+            "alfheim.common.core.asm.hook.fixes.BotaniaGlowingRenderFixes",
+            "alfheim.common.core.asm.hook.fixes.CorporeaInputFix",
+            "alfheim.common.core.asm.hook.fixes.GodAttributesHooks",
+            "alfheim.common.core.asm.hook.fixes.RecipeAncientWillsFix"
+        ))
+    );
+
+    public static final String[] LWJGL3IFY_EXCLUSIONS_SHARED = {
+        "org.embeddedt.embeddium",
+        "org.taumc.celeritas",
+        "com.mitchej123.lwjgl.lwjgl3",
+        "com.mitchej123.glsm",
+        "com.gtnewhorizons.angelica.lwjgl3",
+    };
+
+    public static final String[] EARLY_REDIRECTOR_TARGETS = {
+        "cn.tesseract.mycelium.",
+    };
+
+    private EcosystemNarrowRules() {}
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/loading/TransformerNarrower.java

@@ -0,0 +1,66 @@
+package com.gtnewhorizons.angelica.glsm.loading;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Narrows overly-broad transformer exclusions that prevent the GLSM redirector from
+ * transforming GL calls in mod code. Some coremods register exclusions covering their
+ * entire package tree, which inadvertently shields rendering code from redirection.
+ * <p>
+ * This utility removes the broad exclusion and re-adds narrower ones that cover only
+ * the coremod's own transformer/ASM classes, leaving rendering code exposed.
+ * <p>
+ * Operates on a {@code Set<String>} (the transformer exceptions set from LaunchClassLoader)
+ * and a {@code Map<String, Object>} (the Launch blackboard). Callers extract these from
+ * the Forge/launchwrapper infrastructure.
+ */
+public final class TransformerNarrower {
+
+    private static final Logger LOGGER = LogManager.getLogger("GLSM");
+
+    /**
+     * A rule that replaces a broad transformer exclusion with narrower ones.
+     * @param name       Human-readable name for logging (e.g. "DragonAPI")
+     * @param broad      The broad exclusion to remove (e.g. "Reika.DragonAPI.ASM")
+     * @param narrow     Narrower exclusions to add in its place
+     */
+    public record NarrowRule(String name, String broad, List<String> narrow) {}
+
+    /**
+     * Apply narrowing rules to the transformer exceptions set.
+     *
+     * @param exceptions  The mutable Set from LaunchClassLoader.transformerExceptions
+     * @param blackboard  The Launch.blackboard map (checked for disable flags)
+     * @param keyPrefix   Blackboard key prefix for per-rule opt-out (e.g. "angelica" or "umbra").
+     *                    Rule "DragonAPI" checks key "{prefix}.narrow.DragonAPI". If explicitly
+     *                    set to Boolean.FALSE, the rule is skipped.
+     * @param callerName  Name for log messages (e.g. "Angelica" or "Umbra")
+     * @param rules       The narrowing rules to apply
+     * @return number of rules that were applied
+     */
+    public static int narrow(Set<String> exceptions, Map<String, Object> blackboard,
+                             String keyPrefix, String callerName, List<NarrowRule> rules) {
+        int applied = 0;
+        for (NarrowRule rule : rules) {
+            final String key = keyPrefix + ".narrow." + rule.name();
+            if (Boolean.FALSE.equals(blackboard.get(key))) {
+                continue;
+            }
+            if (exceptions.remove(rule.broad())) {
+                for (String narrow : rule.narrow()) {
+                    exceptions.add(narrow);
+                }
+                LOGGER.info("[{}] Narrowed {} transformer exclusion to allow GL redirection", callerName, rule.broad());
+                applied++;
+            }
+        }
+        return applied;
+    }
+
+    private TransformerNarrower() {}
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/AccumulatedDraw.java

@@ -0,0 +1,59 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.DirectTessellator;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormat;
+
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Represents an accumulated draw call during display list compilation.
+ * Matrix-as-Data Architecture: Stores untransformed vertices + captured matrix.
+ * The matrix will be applied at runtime, not baked into vertices.
+ */
+public final class AccumulatedDraw {
+    public final VertexFormat format;
+    public final List<ByteBuffer> drawBuffers;
+    public final int drawMode;
+    public RestoreData restoreData;
+
+    public AccumulatedDraw(DirectTessellator tessellator, boolean copyLast) {
+        this.format = tessellator.getVertexFormat();
+        this.drawMode = tessellator.drawMode;
+        this.drawBuffers = new ArrayList<>();
+        this.drawBuffers.add(tessellator.allocateBufferCopy());
+
+        if (copyLast) {
+            this.restoreData = new RestoreData(tessellator);
+        }
+    }
+
+
+    public void mergeDraw(DirectTessellator tessellator, boolean copyLast) {
+        this.drawBuffers.add(tessellator.allocateBufferCopy());
+        if (copyLast) {
+            this.restoreData = new RestoreData(tessellator);
+        }
+    }
+
+    /**
+     * Holds last vertex attribute values for GL state restoration after VBO draw.
+     * Used to sync GLSM cache with actual GL state after VBO rendering.
+     */
+    public static final class RestoreData {
+        public final int lastColor;
+        public final int lastNormal;
+        public final float lastTexCoordU;
+        public final float lastTexCoordV;
+        public final int flags;
+
+        public RestoreData(DirectTessellator tessellator) {
+            this.lastColor = tessellator.getPackedColor();
+            this.lastNormal = tessellator.getPackedNormal();
+            this.lastTexCoordU = (float) tessellator.getLastTextureU();
+            this.lastTexCoordV = (float) tessellator.getLastTextureV();
+            this.flags = tessellator.getVertexFormat().getVertexFlags();
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/AttribSnapshot.java

@@ -0,0 +1,178 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.ffp.VAOManager;
+import it.unimi.dsi.fastutil.ints.Int2LongOpenHashMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
+
+public final class AttribSnapshot {
+
+    public record AttribDesc(int location, int size, int type, boolean normalized, int stride, long offset, int sourceVboId, ByteBuffer readBuffer, long readBufferBaseOffset) {
+        public int effectiveStride() {
+            return stride != 0 ? stride : size * VAOManager.Attrib.glTypeSizeBytes(type);
+        }
+
+        public int typeSizeBytes() {
+            return VAOManager.Attrib.glTypeSizeBytes(type);
+        }
+    }
+
+    private final AttribDesc[] perLocation;
+    private final List<ByteBuffer> allocatedBuffers;
+    private boolean freed;
+
+    private AttribSnapshot(AttribDesc[] perLocation, List<ByteBuffer> allocatedBuffers) {
+        this.perLocation = perLocation;
+        this.allocatedBuffers = allocatedBuffers;
+    }
+
+    public AttribDesc get(int location) {
+        return (location >= 0 && location < perLocation.length) ? perLocation[location] : null;
+    }
+
+    public int maxLocations() {
+        return perLocation.length;
+    }
+
+    public void free() {
+        if (freed) return;
+        freed = true;
+        for (ByteBuffer buf : allocatedBuffers) {
+            MemoryUtilities.memFree(buf);
+        }
+        allocatedBuffers.clear();
+    }
+
+    /**
+     * Snapshot attribs over a tight vertex window {@code [firstVertex, firstVertex+vertexCount)}.
+     *
+     * <p>Hot path (single VBO backing every enabled attrib — the typical draw) runs without
+     * allocating any hashmaps. A second distinct VBO promotes to the map-backed fallback.
+     */
+    public static AttribSnapshot snapshot(int firstVertex, int vertexCount) {
+        final AttribDesc[] out = new AttribDesc[VAOManager.MAX_ATTRIBS];
+        final List<ByteBuffer> allocated = new ArrayList<>();
+        final int prevVBO = GLStateManager.getBoundVBO();
+
+        // Pass 1 — unioned [start,end] per vboId. Hot path: one source VBO, zero allocations.
+        int rangeSoleVboId = 0;
+        long rangeSoleStart = Long.MAX_VALUE;
+        long rangeSoleEnd = Long.MIN_VALUE;
+        Int2ObjectOpenHashMap<long[]> vboRanges = null;
+
+        final long lastVtx = (long) firstVertex + vertexCount - 1;
+        for (int i = 0; i < VAOManager.MAX_ATTRIBS; i++) {
+            final VAOManager.Attrib a = VAOManager.get(i);
+            if (a == null || !a.enabled || a.vboId == 0) continue;
+            final int stride = a.effectiveStride();
+            final long typeBytes = (long) a.size * VAOManager.Attrib.glTypeSizeBytes(a.type);
+            final long start = a.offset + (long) firstVertex * stride;
+            final long end = a.offset + lastVtx * stride + typeBytes;
+
+            if (vboRanges != null) {
+                long[] r = vboRanges.get(a.vboId);
+                if (r == null) {
+                    vboRanges.put(a.vboId, new long[] { start, end });
+                } else {
+                    if (start < r[0]) r[0] = start;
+                    if (end > r[1]) r[1] = end;
+                }
+            } else if (rangeSoleVboId == 0 || rangeSoleVboId == a.vboId) {
+                rangeSoleVboId = a.vboId;
+                if (start < rangeSoleStart) rangeSoleStart = start;
+                if (end > rangeSoleEnd) rangeSoleEnd = end;
+            } else {
+                // Spill: second distinct vboId. Promote the accumulated range to the map.
+                vboRanges = new Int2ObjectOpenHashMap<>();
+                vboRanges.put(rangeSoleVboId, new long[] { rangeSoleStart, rangeSoleEnd });
+                vboRanges.put(a.vboId, new long[] { start, end });
+            }
+        }
+
+        // Pass 2 — readback cache. Same spill pattern.
+        int readSoleVboId = 0;
+        ByteBuffer readSoleBuf = null;
+        long readSoleOffset = 0;
+        Int2ObjectOpenHashMap<ByteBuffer> vboBuffers = null;
+        Int2LongOpenHashMap vboReadOffsets = null;
+
+        try {
+            for (int i = 0; i < VAOManager.MAX_ATTRIBS; i++) {
+                final VAOManager.Attrib a = VAOManager.get(i);
+                if (a == null || !a.enabled) continue;
+
+                if (a.vboId != 0) {
+                    ByteBuffer buf;
+                    long readOffset;
+                    if (vboBuffers != null) {
+                        buf = vboBuffers.get(a.vboId);
+                        readOffset = buf != null ? vboReadOffsets.get(a.vboId) : 0;
+                    } else if (readSoleVboId == a.vboId) {
+                        buf = readSoleBuf;
+                        readOffset = readSoleOffset;
+                    } else {
+                        buf = null;
+                        readOffset = 0;
+                    }
+
+                    if (buf == null) {
+                        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, a.vboId);
+                        final int bufferSize = GLStateManager.glGetBufferParameteri(GL15.GL_ARRAY_BUFFER, GL15.GL_BUFFER_SIZE);
+                        if (bufferSize <= 0) {
+                            GLStateManager.LOGGER.warn("[VBO Readback] GL_BUFFER_SIZE={} for VBO {}", bufferSize, a.vboId);
+                            continue;
+                        }
+
+                        final long rStart;
+                        final long rEnd;
+                        if (vboRanges != null) {
+                            final long[] range = vboRanges.get(a.vboId);
+                            rStart = range[0];
+                            rEnd = range[1];
+                        } else {
+                            rStart = rangeSoleStart;
+                            rEnd = rangeSoleEnd;
+                        }
+                        final long ro = Math.max(0, rStart);
+                        final int rs = (int) (Math.min(bufferSize, rEnd) - ro);
+                        if (rs <= 0) continue;
+
+                        buf = MemoryUtilities.memAlloc(rs);
+                        GLStateManager.glGetBufferSubData(GL15.GL_ARRAY_BUFFER, ro, buf);
+                        allocated.add(buf);
+                        readOffset = ro;
+
+                        if (vboBuffers != null) {
+                            vboBuffers.put(a.vboId, buf);
+                            vboReadOffsets.put(a.vboId, ro);
+                        } else if (readSoleVboId == 0) {
+                            readSoleVboId = a.vboId;
+                            readSoleBuf = buf;
+                            readSoleOffset = ro;
+                        } else {
+                            vboBuffers = new Int2ObjectOpenHashMap<>();
+                            vboReadOffsets = new Int2LongOpenHashMap();
+                            vboBuffers.put(readSoleVboId, readSoleBuf);
+                            vboReadOffsets.put(readSoleVboId, readSoleOffset);
+                            vboBuffers.put(a.vboId, buf);
+                            vboReadOffsets.put(a.vboId, ro);
+                        }
+                    }
+                    out[i] = new AttribDesc(i, a.size, a.type, a.normalized, a.stride, a.offset, a.vboId, buf, readOffset);
+                } else if (a.clientPointer != null) {
+                    out[i] = new AttribDesc(i, a.size, a.type, a.normalized, a.stride, a.clientPointer.position(), 0, a.clientPointer, 0L);
+                }
+            }
+        } finally {
+            GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, prevVBO);
+        }
+
+        return new AttribSnapshot(out, allocated);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/CommandBufferExecutor.java

@@ -0,0 +1,530 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
+import com.gtnewhorizons.angelica.glsm.DisplayListManager;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.recording.commands.DisplayListCommand;
+import org.lwjgl.BufferUtils;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+import java.nio.DoubleBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAddress;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetDouble;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetFloat;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetInt;
+
+/**
+ * Executes commands from a CommandBuffer
+ */
+public final class CommandBufferExecutor {
+    private CommandBufferExecutor() {}
+
+    // Static reusable buffer for matrix ops (render thread only, LWJGL2/3 compatible)
+    private static final FloatBuffer MATRIX_BUFFER = BufferUtils.createFloatBuffer(16);
+    // Static reusable buffer for fog/light/material params
+    private static final FloatBuffer PARAMS_BUFFER = BufferUtils.createFloatBuffer(4);
+    // Static reusable buffer for clip plane equation
+    private static final DoubleBuffer PARAMS_DOUBLE_BUFFER = BufferUtils.createDoubleBuffer(4);
+    // Static reusable buffer for draw buffers
+    private static final int MAX_DRAW_BUFFERS = 8;
+    private static final IntBuffer DRAW_BUFFERS_BUFFER = BufferUtils.createIntBuffer(MAX_DRAW_BUFFERS);
+
+    /**
+     * Execute all commands in the buffer.
+     *
+     * @param buffer The command buffer (position should be at 0, limit at size)
+     * @param complexObjects Array of complex objects (TexImage2DCmd, etc.)
+     * @param ownedVbos Array of VBOs owned by the display list (indexed by DrawRange commands)
+     */
+    public static void execute(
+        ByteBuffer buffer,
+        DisplayListCommand[] complexObjects,
+        DisplayListVBO ownedVbos,
+        int list,
+        CompiledDisplayList compiledDisplayList
+    ) {
+        long ptr = memAddress(buffer);
+        final long end = ptr + buffer.limit();
+
+        while (ptr < end) {
+            final int cmd = memGetInt(ptr);
+            ptr += 4;
+
+            switch (cmd) {
+                // === Single int commands ===
+                case GLCommand.ENABLE -> {
+                    GLStateManager.glEnable(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.DISABLE -> {
+                    GLStateManager.glDisable(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.CLEAR -> {
+                    GLStateManager.glClear(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.CLEAR_STENCIL -> {
+                    GLStateManager.glClearStencil(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.CULL_FACE -> {
+                    GLStateManager.glCullFace(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.DEPTH_FUNC -> {
+                    GLStateManager.glDepthFunc(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.SHADE_MODEL -> {
+                    GLStateManager.glShadeModel(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.LOGIC_OP -> {
+                    GLStateManager.glLogicOp(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.MATRIX_MODE -> {
+                    GLStateManager.glMatrixMode(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.ACTIVE_TEXTURE -> {
+                    GLStateManager.glActiveTexture(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.USE_PROGRAM -> {
+                    GLStateManager.glUseProgram(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.PUSH_ATTRIB -> {
+                    GLStateManager.glPushAttrib(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.POP_ATTRIB -> {
+                    GLStateManager.glPopAttrib();
+                    ptr += 4; // Skip unused padding
+                }
+                case GLCommand.LOAD_IDENTITY -> {
+                    GLStateManager.glLoadIdentity();
+                }
+                case GLCommand.PUSH_MATRIX -> {
+                    GLStateManager.glPushMatrix();
+                }
+                case GLCommand.POP_MATRIX -> {
+                    GLStateManager.glPopMatrix();
+                }
+                case GLCommand.STENCIL_MASK -> {
+                    GLStateManager.glStencilMask(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.DEPTH_MASK -> {
+                    GLStateManager.glDepthMask(memGetInt(ptr) != 0);
+                    ptr += 4;
+                }
+                case GLCommand.FRONT_FACE -> {
+                    GLStateManager.glFrontFace(memGetInt(ptr));
+                    ptr += 4;
+                }
+
+                // === Two int commands ===
+                case GLCommand.BIND_TEXTURE -> {
+                    final int target = memGetInt(ptr);
+                    final int texture = memGetInt(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glBindTexture(target, texture);
+                }
+                case GLCommand.POLYGON_MODE -> {
+                    final int face = memGetInt(ptr);
+                    final int mode = memGetInt(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glPolygonMode(face, mode);
+                }
+                case GLCommand.COLOR_MATERIAL -> {
+                    final int face = memGetInt(ptr);
+                    final int mode = memGetInt(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glColorMaterial(face, mode);
+                }
+                case GLCommand.LINE_STIPPLE -> {
+                    final int factor = memGetInt(ptr);
+                    final int pattern = memGetInt(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glLineStipple(factor, (short) pattern);
+                }
+                case GLCommand.STENCIL_MASK_SEPARATE -> {
+                    final int face = memGetInt(ptr);
+                    final int mask = memGetInt(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glStencilMaskSeparate(face, mask);
+                }
+                case GLCommand.FOGI -> {
+                    final int pname = memGetInt(ptr);
+                    final int param = memGetInt(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glFogi(pname, param);
+                }
+                case GLCommand.HINT -> {
+                    final int target = memGetInt(ptr);
+                    final int mode = memGetInt(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glHint(target, mode);
+                }
+
+                // === Three int commands ===
+                case GLCommand.STENCIL_FUNC -> {
+                    final int func = memGetInt(ptr);
+                    final int ref = memGetInt(ptr + 4);
+                    final int mask = memGetInt(ptr + 8);
+                    ptr += 12;
+                    GLStateManager.glStencilFunc(func, ref, mask);
+                }
+                case GLCommand.STENCIL_OP -> {
+                    final int fail = memGetInt(ptr);
+                    final int zfail = memGetInt(ptr + 4);
+                    final int zpass = memGetInt(ptr + 8);
+                    ptr += 12;
+                    GLStateManager.glStencilOp(fail, zfail, zpass);
+                }
+                case GLCommand.TEX_PARAMETERI -> {
+                    final int target = memGetInt(ptr);
+                    final int pname = memGetInt(ptr + 4);
+                    final int param = memGetInt(ptr + 8);
+                    ptr += 12;
+                    GLStateManager.glTexParameteri(target, pname, param);
+                }
+
+                // === Four int commands ===
+                case GLCommand.VIEWPORT -> {
+                    final int x = memGetInt(ptr);
+                    final int y = memGetInt(ptr + 4);
+                    final int width = memGetInt(ptr + 8);
+                    final int height = memGetInt(ptr + 12);
+                    ptr += 16;
+                    GLStateManager.glViewport(x, y, width, height);
+                }
+                case GLCommand.SCISSOR -> {
+                    final int x = memGetInt(ptr);
+                    final int y = memGetInt(ptr + 4);
+                    final int width = memGetInt(ptr + 8);
+                    final int height = memGetInt(ptr + 12);
+                    ptr += 16;
+                    GLStateManager.glScissor(x, y, width, height);
+                }
+                case GLCommand.BLEND_FUNC -> {
+                    final int srcRgb = memGetInt(ptr);
+                    final int dstRgb = memGetInt(ptr + 4);
+                    final int srcAlpha = memGetInt(ptr + 8);
+                    final int dstAlpha = memGetInt(ptr + 12);
+                    ptr += 16;
+                    if (srcRgb == srcAlpha && dstRgb == dstAlpha) {
+                        GLStateManager.glBlendFunc(srcRgb, dstRgb);
+                    } else {
+                        GLStateManager.tryBlendFuncSeparate(srcRgb, dstRgb, srcAlpha, dstAlpha);
+                    }
+                }
+                case GLCommand.COLOR_MASK -> {
+                    final boolean r = memGetInt(ptr) != 0;
+                    final boolean g = memGetInt(ptr + 4) != 0;
+                    final boolean b = memGetInt(ptr + 8) != 0;
+                    final boolean a = memGetInt(ptr + 12) != 0;
+                    ptr += 16;
+                    GLStateManager.glColorMask(r, g, b, a);
+                }
+                case GLCommand.STENCIL_FUNC_SEPARATE -> {
+                    final int face = memGetInt(ptr);
+                    final int func = memGetInt(ptr + 4);
+                    final int ref = memGetInt(ptr + 8);
+                    final int mask = memGetInt(ptr + 12);
+                    ptr += 16;
+                    GLStateManager.glStencilFuncSeparate(face, func, ref, mask);
+                }
+                case GLCommand.STENCIL_OP_SEPARATE -> {
+                    final int face = memGetInt(ptr);
+                    final int sfail = memGetInt(ptr + 4);
+                    final int dpfail = memGetInt(ptr + 8);
+                    final int dppass = memGetInt(ptr + 12);
+                    ptr += 16;
+                    GLStateManager.glStencilOpSeparate(face, sfail, dpfail, dppass);
+                }
+
+                // === Float commands ===
+                case GLCommand.POINT_SIZE -> {
+                    GLStateManager.glPointSize(memGetFloat(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.LINE_WIDTH -> {
+                    GLStateManager.glLineWidth(memGetFloat(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.POLYGON_OFFSET -> {
+                    final float factor = memGetFloat(ptr);
+                    final float units = memGetFloat(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glPolygonOffset(factor, units);
+                }
+                case GLCommand.COLOR -> {
+                    final float r = memGetFloat(ptr);
+                    final float g = memGetFloat(ptr + 4);
+                    final float b = memGetFloat(ptr + 8);
+                    final float a = memGetFloat(ptr + 12);
+                    ptr += 16;
+                    GLStateManager.glColor4f(r, g, b, a);
+                }
+                case GLCommand.CLEAR_COLOR -> {
+                    final float r = memGetFloat(ptr);
+                    final float g = memGetFloat(ptr + 4);
+                    final float b = memGetFloat(ptr + 8);
+                    final float a = memGetFloat(ptr + 12);
+                    ptr += 16;
+                    GLStateManager.glClearColor(r, g, b, a);
+                }
+                case GLCommand.CLEAR_DEPTH -> {
+                    final double depth = memGetDouble(ptr);
+                    ptr += 8;
+                    GLStateManager.glClearDepth(depth);
+                }
+                case GLCommand.BLEND_COLOR -> {
+                    final float r = memGetFloat(ptr);
+                    final float g = memGetFloat(ptr + 4);
+                    final float b = memGetFloat(ptr + 8);
+                    final float a = memGetFloat(ptr + 12);
+                    ptr += 16;
+                    GLStateManager.glBlendColor(r, g, b, a);
+                }
+
+                // === Mixed int+float commands ===
+                case GLCommand.ALPHA_FUNC -> {
+                    final int func = memGetInt(ptr);
+                    final float ref = memGetFloat(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glAlphaFunc(func, ref);
+                }
+                case GLCommand.FOGF -> {
+                    final int pname = memGetInt(ptr);
+                    final float param = memGetFloat(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glFogf(pname, param);
+                }
+                case GLCommand.LIGHTF -> {
+                    final int light = memGetInt(ptr);
+                    final int pname = memGetInt(ptr + 4);
+                    final float param = memGetFloat(ptr + 8);
+                    ptr += 12;
+                    GLStateManager.glLightf(light, pname, param);
+                }
+                case GLCommand.LIGHT_MODELF -> {
+                    final int pname = memGetInt(ptr);
+                    final float param = memGetFloat(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glLightModelf(pname, param);
+                }
+                case GLCommand.LIGHTI -> {
+                    final int light = memGetInt(ptr);
+                    final int pname = memGetInt(ptr + 4);
+                    final int param = memGetInt(ptr + 8);
+                    ptr += 12;
+                    GLStateManager.glLighti(light, pname, param);
+                }
+                case GLCommand.LIGHT_MODELI -> {
+                    final int pname = memGetInt(ptr);
+                    final int param = memGetInt(ptr + 4);
+                    ptr += 8;
+                    GLStateManager.glLightModeli(pname, param);
+                }
+                case GLCommand.MATERIALF -> {
+                    final int face = memGetInt(ptr);
+                    final int pname = memGetInt(ptr + 4);
+                    final float param = memGetFloat(ptr + 8);
+                    ptr += 12;
+                    GLStateManager.glMaterialf(face, pname, param);
+                }
+                case GLCommand.TEX_PARAMETERF -> {
+                    final int target = memGetInt(ptr);
+                    final int pname = memGetInt(ptr + 4);
+                    final float param = memGetFloat(ptr + 8);
+                    ptr += 12;
+                    GLStateManager.glTexParameterf(target, pname, param);
+                }
+
+                // === Matrix commands ===
+                case GLCommand.MULT_MATRIX -> {
+                    // Mode-agnostic: just multiply current matrix
+                    MATRIX_BUFFER.clear();
+                    for (int i = 0; i < 16; i++) {
+                        MATRIX_BUFFER.put(memGetFloat(ptr));
+                        ptr += 4;
+                    }
+                    MATRIX_BUFFER.flip();
+                    GLStateManager.glMultMatrix(MATRIX_BUFFER);
+                }
+                case GLCommand.TRANSLATE -> {
+                    final float x = memGetFloat(ptr);
+                    final float y = memGetFloat(ptr + 4);
+                    final float z = memGetFloat(ptr + 8);
+                    ptr += 12;
+                    GLStateManager.glTranslatef(x, y, z);
+                }
+                case GLCommand.SCALE -> {
+                    final float x = memGetFloat(ptr);
+                    final float y = memGetFloat(ptr + 4);
+                    final float z = memGetFloat(ptr + 8);
+                    ptr += 12;
+                    GLStateManager.glScalef(x, y, z);
+                }
+                case GLCommand.LOAD_MATRIX -> {
+                    MATRIX_BUFFER.clear();
+                    for (int i = 0; i < 16; i++) {
+                        MATRIX_BUFFER.put(memGetFloat(ptr));
+                        ptr += 4;
+                    }
+                    MATRIX_BUFFER.flip();
+                    GLStateManager.glLoadMatrix(MATRIX_BUFFER);
+                }
+
+                // === Buffer commands ===
+                case GLCommand.FOG -> {
+                    final int pname = memGetInt(ptr);
+                    final int count = memGetInt(ptr + 4);
+                    ptr += 8;
+                    PARAMS_BUFFER.clear();
+                    for (int i = 0; i < count; i++) {
+                        PARAMS_BUFFER.put(memGetFloat(ptr));
+                        ptr += 4;
+                    }
+                    PARAMS_BUFFER.flip();
+                    GLStateManager.glFog(pname, PARAMS_BUFFER);
+                }
+                case GLCommand.LIGHT -> {
+                    final int light = memGetInt(ptr);
+                    final int pname = memGetInt(ptr + 4);
+                    final int count = memGetInt(ptr + 8);
+                    ptr += 12;
+                    PARAMS_BUFFER.clear();
+                    for (int i = 0; i < count; i++) {
+                        PARAMS_BUFFER.put(memGetFloat(ptr));
+                        ptr += 4;
+                    }
+                    PARAMS_BUFFER.flip();
+                    GLStateManager.glLight(light, pname, PARAMS_BUFFER);
+                }
+                case GLCommand.LIGHT_MODEL -> {
+                    final int pname = memGetInt(ptr);
+                    final int count = memGetInt(ptr + 4);
+                    ptr += 8;
+                    PARAMS_BUFFER.clear();
+                    for (int i = 0; i < count; i++) {
+                        PARAMS_BUFFER.put(memGetFloat(ptr));
+                        ptr += 4;
+                    }
+                    PARAMS_BUFFER.flip();
+                    GLStateManager.glLightModel(pname, PARAMS_BUFFER);
+                }
+                case GLCommand.MATERIAL -> {
+                    final int face = memGetInt(ptr);
+                    final int pname = memGetInt(ptr + 4);
+                    final int count = memGetInt(ptr + 8);
+                    ptr += 12;
+                    PARAMS_BUFFER.clear();
+                    for (int i = 0; i < count; i++) {
+                        PARAMS_BUFFER.put(memGetFloat(ptr));
+                        ptr += 4;
+                    }
+                    PARAMS_BUFFER.flip();
+                    GLStateManager.glMaterial(face, pname, PARAMS_BUFFER);
+                }
+
+                case GLCommand.CLIP_PLANE -> {
+                    final int plane = memGetInt(ptr);
+                    final double a = memGetDouble(ptr + 4);
+                    final double b = memGetDouble(ptr + 12);
+                    final double c = memGetDouble(ptr + 20);
+                    final double d = memGetDouble(ptr + 28);
+                    ptr += 36;
+                    PARAMS_DOUBLE_BUFFER.clear();
+                    PARAMS_DOUBLE_BUFFER.put(a).put(b).put(c).put(d);
+                    PARAMS_DOUBLE_BUFFER.flip();
+                    GLStateManager.glClipPlane(plane, PARAMS_DOUBLE_BUFFER);
+                }
+
+                // === Draw commands ===
+                case GLCommand.DRAW_RANGE -> {
+                    final int vboIndex = memGetInt(ptr);
+                    ptr += 4;
+                    ownedVbos.render(vboIndex);
+                }
+                case GLCommand.DRAW_RANGE_RESTORE -> {
+                    // Draw VBO range then restore GL current state from last vertex attributes
+                    final int vboIndex = memGetInt(ptr);
+                    final int flags = memGetInt(ptr + 4);
+
+                    // Draw the VBO
+                    ownedVbos.render(vboIndex);
+
+                    // Restore attributes based on flags
+                    if ((flags & VertexFlags.COLOR_BIT) != 0) {
+                        final int color = memGetInt(ptr + 8);
+                        final byte a = (byte) ((color >> 24) & 0xFF);
+                        final byte b = (byte) ((color >> 16) & 0xFF);
+                        final byte g = (byte) ((color >> 8) & 0xFF);
+                        final byte r = (byte) ((color & 0xFF));
+                        GLStateManager.glColor4ub(r, g, b, a);
+                    }
+                    if ((flags & VertexFlags.NORMAL_BIT) != 0) {
+                        final int normal = memGetInt(ptr + 12);
+                        float nx = (byte)(normal)       / 127.0f;
+                        float ny = (byte)(normal >> 8)  / 127.0f;
+                        float nz = (byte)(normal >> 16) / 127.0f;
+                        GLStateManager.glNormal3f(nx, ny, nz);
+                    }
+                    if ((flags & VertexFlags.TEXTURE_BIT) != 0) {
+                        final float s = memGetFloat(ptr + 16);
+                        final float t = memGetFloat(ptr + 20);
+                        GLStateManager.glTexCoord2f(s, t);
+                    }
+                    ptr += 24;  // Skip full command size (28 - 4 for cmd already read)
+                }
+                case GLCommand.CALL_LIST -> {
+                    final int listId = memGetInt(ptr);
+                    ptr += 4;
+                    DisplayListManager.glCallList(listId);
+                }
+                case GLCommand.DRAW_BUFFER -> {
+                    GLStateManager.glDrawBuffer(memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.DRAW_BUFFERS -> {
+                    final int count = memGetInt(ptr);
+                    ptr += 4;
+                    DRAW_BUFFERS_BUFFER.clear();
+                    for (int i = 0; i < count; i++) {
+                        DRAW_BUFFERS_BUFFER.put(memGetInt(ptr + i * 4));
+                    }
+                    DRAW_BUFFERS_BUFFER.flip();
+                    ptr += 4 * MAX_DRAW_BUFFERS;
+                    GLStateManager.glDrawBuffers(DRAW_BUFFERS_BUFFER);
+                }
+                case GLCommand.BIND_VBO -> {
+                    GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, memGetInt(ptr));
+                    ptr += 4;
+                }
+                case GLCommand.BIND_VAO -> {
+                    GLStateManager.glBindVertexArray(memGetInt(ptr));
+                    ptr += 4;
+                }
+
+                // === Complex object reference ===
+                case GLCommand.COMPLEX_REF -> {
+                    final int index = memGetInt(ptr);
+                    ptr += 4;
+                    complexObjects[index].execute();
+                }
+
+                default -> throw new IllegalStateException("Unknown command opcode: " + cmd + " in display list with ID " + list + "\n" + DisplayListManager.getCompiledDisplayListString(list, compiledDisplayList, null));
+            }
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/CommandRecorder.java

@@ -0,0 +1,701 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizons.angelica.glsm.recording.commands.DisplayListCommand;
+import com.gtnewhorizons.angelica.glsm.recording.commands.IndexedDrawBatchBuilder;
+import com.gtnewhorizons.angelica.glsm.recording.commands.IndexedDrawCapture;
+import org.joml.Matrix4f;
+import org.joml.Vector3f;
+
+import java.nio.ByteBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+import java.util.ArrayList;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.*;
+
+public final class CommandRecorder {
+    private static final int DEFAULT_CAPACITY = 2048; // Guess at typical display list size
+
+    private ByteBuffer buffer;
+    private long basePointer;
+    private long writePointer;
+    private final ArrayList<DisplayListCommand> complexObjects = new ArrayList<>();
+    private final IndexedDrawBatchBuilder indexedDraws = new IndexedDrawBatchBuilder();
+
+    public CommandRecorder() {
+        this(DEFAULT_CAPACITY);
+    }
+
+    public CommandRecorder(int initialCapacity) {
+        this.buffer = memAlloc(initialCapacity);
+        this.basePointer = memAddress0(buffer);
+        this.writePointer = basePointer;
+    }
+
+    // === Low-level write operations ===
+
+    private void writeInt(int value) {
+        memPutInt(writePointer, value);
+        writePointer += 4;
+    }
+
+    private void writeLong(long value) {
+        memPutLong(writePointer, value);
+        writePointer += 8;
+    }
+
+    private void writeFloat(float value) {
+        memPutFloat(writePointer, value);
+        writePointer += 4;
+    }
+
+    private void writeDouble(double value) {
+        memPutDouble(writePointer, value);
+        writePointer += 8;
+    }
+
+    private void ensureCapacity(int needed) {
+        final int size = size();
+        final int remaining = buffer.capacity() - size;
+        if (remaining < needed) {
+            final int newCapacity = Math.max(buffer.capacity() * 2, buffer.capacity() + needed);
+            buffer = memRealloc(buffer, newCapacity);
+            basePointer = memAddress0(buffer);
+            writePointer = basePointer + size;
+        }
+    }
+
+    public IndexedDrawBatchBuilder getIndexedDraws() {
+        return indexedDraws;
+    }
+
+    public void writeIndexedDrawCapture(IndexedDrawCapture capture) {
+        indexedDraws.add(capture);
+        writeComplexCommand(capture.placeholder);
+    }
+
+    public void free() {
+        for (IndexedDrawCapture c : indexedDraws.getCaptures()) {
+            c.freeBuffers();
+        }
+    }
+
+    // === Single int commands ===
+
+    public void writeEnable(int cap) {
+        ensureCapacity(8);
+        writeInt(GLCommand.ENABLE);
+        writeInt(cap);
+    }
+
+    public void writeDisable(int cap) {
+        ensureCapacity(8);
+        writeInt(GLCommand.DISABLE);
+        writeInt(cap);
+    }
+
+    public void writeClear(int mask) {
+        ensureCapacity(8);
+        writeInt(GLCommand.CLEAR);
+        writeInt(mask);
+    }
+
+    public void writeClearStencil(int s) {
+        ensureCapacity(8);
+        writeInt(GLCommand.CLEAR_STENCIL);
+        writeInt(s);
+    }
+
+    public void writeCullFace(int mode) {
+        ensureCapacity(8);
+        writeInt(GLCommand.CULL_FACE);
+        writeInt(mode);
+    }
+
+    public void writeDepthFunc(int func) {
+        ensureCapacity(8);
+        writeInt(GLCommand.DEPTH_FUNC);
+        writeInt(func);
+    }
+
+    public void writeShadeModel(int mode) {
+        ensureCapacity(8);
+        writeInt(GLCommand.SHADE_MODEL);
+        writeInt(mode);
+    }
+
+    public void writeLogicOp(int opcode) {
+        ensureCapacity(8);
+        writeInt(GLCommand.LOGIC_OP);
+        writeInt(opcode);
+    }
+
+    public void writeMatrixMode(int mode) {
+        ensureCapacity(8);
+        writeInt(GLCommand.MATRIX_MODE);
+        writeInt(mode);
+    }
+
+    public void writeActiveTexture(int texture) {
+        ensureCapacity(8);
+        writeInt(GLCommand.ACTIVE_TEXTURE);
+        writeInt(texture);
+    }
+
+    public void writeUseProgram(int program) {
+        ensureCapacity(8);
+        writeInt(GLCommand.USE_PROGRAM);
+        writeInt(program);
+    }
+
+    public void writePushAttrib(int mask) {
+        ensureCapacity(8);
+        writeInt(GLCommand.PUSH_ATTRIB);
+        writeInt(mask);
+    }
+
+    public void writePopAttrib() {
+        ensureCapacity(8);
+        writeInt(GLCommand.POP_ATTRIB);
+        writeInt(0); // unused padding
+    }
+
+    public void writeLoadIdentity() {
+        ensureCapacity(4);
+        writeInt(GLCommand.LOAD_IDENTITY);
+    }
+
+    public void writePushMatrix() {
+        ensureCapacity(4);
+        writeInt(GLCommand.PUSH_MATRIX);
+    }
+
+    public void writePopMatrix() {
+        ensureCapacity(4);
+        writeInt(GLCommand.POP_MATRIX);
+    }
+
+    public void writeStencilMask(int mask) {
+        ensureCapacity(8);
+        writeInt(GLCommand.STENCIL_MASK);
+        writeInt(mask);
+    }
+
+    public void writeDepthMask(boolean flag) {
+        ensureCapacity(8);
+        writeInt(GLCommand.DEPTH_MASK);
+        writeInt(flag ? 1 : 0);
+    }
+
+    public void writeFrontFace(int mode) {
+        ensureCapacity(8);
+        writeInt(GLCommand.FRONT_FACE);
+        writeInt(mode);
+    }
+
+    // === Two int commands ===
+
+    public void writeBindTexture(int target, int texture) {
+        ensureCapacity(12);
+        writeInt(GLCommand.BIND_TEXTURE);
+        writeInt(target);
+        writeInt(texture);
+    }
+
+    public void writePolygonMode(int face, int mode) {
+        ensureCapacity(12);
+        writeInt(GLCommand.POLYGON_MODE);
+        writeInt(face);
+        writeInt(mode);
+    }
+
+    public void writeColorMaterial(int face, int mode) {
+        ensureCapacity(12);
+        writeInt(GLCommand.COLOR_MATERIAL);
+        writeInt(face);
+        writeInt(mode);
+    }
+
+    public void writeLineStipple(int factor, int pattern) {
+        ensureCapacity(12);
+        writeInt(GLCommand.LINE_STIPPLE);
+        writeInt(factor);
+        writeInt(pattern);
+    }
+
+    public void writeStencilMaskSeparate(int face, int mask) {
+        ensureCapacity(12);
+        writeInt(GLCommand.STENCIL_MASK_SEPARATE);
+        writeInt(face);
+        writeInt(mask);
+    }
+
+    public void writeFogi(int pname, int param) {
+        ensureCapacity(12);
+        writeInt(GLCommand.FOGI);
+        writeInt(pname);
+        writeInt(param);
+    }
+
+    public void writeHint(int target, int mode) {
+        ensureCapacity(12);
+        writeInt(GLCommand.HINT);
+        writeInt(target);
+        writeInt(mode);
+    }
+
+    // === Three int commands ===
+
+    public void writeStencilFunc(int func, int ref, int mask) {
+        ensureCapacity(16);
+        writeInt(GLCommand.STENCIL_FUNC);
+        writeInt(func);
+        writeInt(ref);
+        writeInt(mask);
+    }
+
+    public void writeStencilOp(int fail, int zfail, int zpass) {
+        ensureCapacity(16);
+        writeInt(GLCommand.STENCIL_OP);
+        writeInt(fail);
+        writeInt(zfail);
+        writeInt(zpass);
+    }
+
+    public void writeTexParameteri(int target, int pname, int param) {
+        ensureCapacity(16);
+        writeInt(GLCommand.TEX_PARAMETERI);
+        writeInt(target);
+        writeInt(pname);
+        writeInt(param);
+    }
+
+    // === Four int commands ===
+
+    public void writeViewport(int x, int y, int width, int height) {
+        ensureCapacity(20);
+        writeInt(GLCommand.VIEWPORT);
+        writeInt(x);
+        writeInt(y);
+        writeInt(width);
+        writeInt(height);
+    }
+
+    public void writeScissor(int x, int y, int width, int height) {
+        ensureCapacity(20);
+        writeInt(GLCommand.SCISSOR);
+        writeInt(x);
+        writeInt(y);
+        writeInt(width);
+        writeInt(height);
+    }
+
+    public void writeBlendFunc(int srcRgb, int dstRgb, int srcAlpha, int dstAlpha) {
+        ensureCapacity(20);
+        writeInt(GLCommand.BLEND_FUNC);
+        writeInt(srcRgb);
+        writeInt(dstRgb);
+        writeInt(srcAlpha);
+        writeInt(dstAlpha);
+    }
+
+    public void writeColorMask(boolean red, boolean green, boolean blue, boolean alpha) {
+        ensureCapacity(20);
+        writeInt(GLCommand.COLOR_MASK);
+        writeInt(red ? 1 : 0);
+        writeInt(green ? 1 : 0);
+        writeInt(blue ? 1 : 0);
+        writeInt(alpha ? 1 : 0);
+    }
+
+    public void writeStencilFuncSeparate(int face, int func, int ref, int mask) {
+        ensureCapacity(20);
+        writeInt(GLCommand.STENCIL_FUNC_SEPARATE);
+        writeInt(face);
+        writeInt(func);
+        writeInt(ref);
+        writeInt(mask);
+    }
+
+    public void writeStencilOpSeparate(int face, int sfail, int dpfail, int dppass) {
+        ensureCapacity(20);
+        writeInt(GLCommand.STENCIL_OP_SEPARATE);
+        writeInt(face);
+        writeInt(sfail);
+        writeInt(dpfail);
+        writeInt(dppass);
+    }
+
+    // === Float commands ===
+
+    public void writePointSize(float size) {
+        ensureCapacity(8);
+        writeInt(GLCommand.POINT_SIZE);
+        writeFloat(size);
+    }
+
+    public void writeLineWidth(float width) {
+        ensureCapacity(8);
+        writeInt(GLCommand.LINE_WIDTH);
+        writeFloat(width);
+    }
+
+    public void writePolygonOffset(float factor, float units) {
+        ensureCapacity(12);
+        writeInt(GLCommand.POLYGON_OFFSET);
+        writeFloat(factor);
+        writeFloat(units);
+    }
+
+    public void writeColor(float r, float g, float b, float a) {
+        ensureCapacity(20);
+        writeInt(GLCommand.COLOR);
+        writeFloat(r);
+        writeFloat(g);
+        writeFloat(b);
+        writeFloat(a);
+    }
+
+    public void writeClearColor(float r, float g, float b, float a) {
+        ensureCapacity(20);
+        writeInt(GLCommand.CLEAR_COLOR);
+        writeFloat(r);
+        writeFloat(g);
+        writeFloat(b);
+        writeFloat(a);
+    }
+
+    public void writeClearDepth(double depth) {
+        ensureCapacity(12);
+        writeInt(GLCommand.CLEAR_DEPTH);
+        writeDouble(depth);
+    }
+
+    public void writeBlendColor(float r, float g, float b, float a) {
+        ensureCapacity(20);
+        writeInt(GLCommand.BLEND_COLOR);
+        writeFloat(r);
+        writeFloat(g);
+        writeFloat(b);
+        writeFloat(a);
+    }
+
+    // === Mixed int+float commands ===
+
+    public void writeAlphaFunc(int func, float ref) {
+        ensureCapacity(12);
+        writeInt(GLCommand.ALPHA_FUNC);
+        writeInt(func);
+        writeFloat(ref);
+    }
+
+    public void writeFogf(int pname, float param) {
+        ensureCapacity(12);
+        writeInt(GLCommand.FOGF);
+        writeInt(pname);
+        writeFloat(param);
+    }
+
+    public void writeLightf(int light, int pname, float param) {
+        ensureCapacity(16);
+        writeInt(GLCommand.LIGHTF);
+        writeInt(light);
+        writeInt(pname);
+        writeFloat(param);
+    }
+
+    public void writeLightModelf(int pname, float param) {
+        ensureCapacity(12);
+        writeInt(GLCommand.LIGHT_MODELF);
+        writeInt(pname);
+        writeFloat(param);
+    }
+
+    public void writeLighti(int light, int pname, int param) {
+        ensureCapacity(16);
+        writeInt(GLCommand.LIGHTI);
+        writeInt(light);
+        writeInt(pname);
+        writeInt(param);
+    }
+
+    public void writeLightModeli(int pname, int param) {
+        ensureCapacity(12);
+        writeInt(GLCommand.LIGHT_MODELI);
+        writeInt(pname);
+        writeInt(param);
+    }
+
+    public void writeMaterialf(int face, int pname, float param) {
+        ensureCapacity(16);
+        writeInt(GLCommand.MATERIALF);
+        writeInt(face);
+        writeInt(pname);
+        writeFloat(param);
+    }
+
+    public void writeTexParameterf(int target, int pname, float param) {
+        ensureCapacity(16);
+        writeInt(GLCommand.TEX_PARAMETERF);
+        writeInt(target);
+        writeInt(pname);
+        writeFloat(param);
+    }
+
+    // === Transformation commands ===
+
+    public void writeTranslate(Vector3f translationVector) {
+        ensureCapacity(16);
+        writeInt(GLCommand.TRANSLATE);
+        writeFloat(translationVector.x);
+        writeFloat(translationVector.y);
+        writeFloat(translationVector.z);
+    }
+
+    public void writeScale(Vector3f scaleVector) {
+        ensureCapacity(16);
+        writeInt(GLCommand.SCALE);
+        writeFloat(scaleVector.x);
+        writeFloat(scaleVector.y);
+        writeFloat(scaleVector.z);
+    }
+
+    // === Matrix commands ===
+
+    public void writeMultMatrix(Matrix4f matrix) {
+        ensureCapacity(68);
+        writeInt(GLCommand.MULT_MATRIX);
+        writeMatrix4f(matrix);
+    }
+
+    public void writeLoadMatrix(Matrix4f matrix) {
+        ensureCapacity(68);
+        writeInt(GLCommand.LOAD_MATRIX);
+        writeMatrix4f(matrix);
+    }
+
+    /**
+     * Write a Matrix4f to the buffer in column-major order (OpenGL convention).
+     * Uses accessor methods instead of getToAddress() to avoid JOML MemUtil issues.
+     */
+    private void writeMatrix4f(Matrix4f m) {
+        // Column 0
+        writeFloat(m.m00()); writeFloat(m.m01()); writeFloat(m.m02()); writeFloat(m.m03());
+        // Column 1
+        writeFloat(m.m10()); writeFloat(m.m11()); writeFloat(m.m12()); writeFloat(m.m13());
+        // Column 2
+        writeFloat(m.m20()); writeFloat(m.m21()); writeFloat(m.m22()); writeFloat(m.m23());
+        // Column 3
+        writeFloat(m.m30()); writeFloat(m.m31()); writeFloat(m.m32()); writeFloat(m.m33());
+    }
+
+    // === Buffer commands (inline 4 floats) ===
+
+    public void writeFog(int pname, FloatBuffer params) {
+        final int count = Math.min(params.remaining(), 4);
+        ensureCapacity(12 + count * 4);
+        writeInt(GLCommand.FOG);
+        writeInt(pname);
+        writeInt(count);
+        final int pos = params.position();
+        for (int i = 0; i < count; i++) {
+            writeFloat(params.get(pos + i));
+        }
+    }
+
+    public void writeLight(int light, int pname, FloatBuffer params) {
+        final int count = Math.min(params.remaining(), 4);
+        ensureCapacity(16 + count * 4);
+        writeInt(GLCommand.LIGHT);
+        writeInt(light);
+        writeInt(pname);
+        writeInt(count);
+        final int pos = params.position();
+        for (int i = 0; i < count; i++) {
+            writeFloat(params.get(pos + i));
+        }
+    }
+
+    public void writeLightModel(int pname, FloatBuffer params) {
+        final int count = Math.min(params.remaining(), 4);
+        ensureCapacity(12 + count * 4);
+        writeInt(GLCommand.LIGHT_MODEL);
+        writeInt(pname);
+        writeInt(count);
+        final int pos = params.position();
+        for (int i = 0; i < count; i++) {
+            writeFloat(params.get(pos + i));
+        }
+    }
+
+    public void writeMaterial(int face, int pname, FloatBuffer params) {
+        final int count = Math.min(params.remaining(), 4);
+        ensureCapacity(16 + count * 4);
+        writeInt(GLCommand.MATERIAL);
+        writeInt(face);
+        writeInt(pname);
+        writeInt(count);
+        final int pos = params.position();
+        for (int i = 0; i < count; i++) {
+            writeFloat(params.get(pos + i));
+        }
+    }
+
+    public void writeClipPlane(int plane, double a, double b, double c, double d) {
+        ensureCapacity(40);
+        writeInt(GLCommand.CLIP_PLANE);
+        writeInt(plane);
+        writeDouble(a);
+        writeDouble(b);
+        writeDouble(c);
+        writeDouble(d);
+    }
+
+    // === Draw commands ===
+
+    public void writeDrawRange(int vboIndex) {
+        ensureCapacity(8);
+        writeInt(GLCommand.DRAW_RANGE);
+        writeInt(vboIndex);
+    }
+
+    /**
+     * Write a DRAW_RANGE_RESTORE command that draws a VBO range and restores GL current state after.
+     * Used for immediate mode VBOs to restore GL_CURRENT_COLOR, GL_CURRENT_NORMAL, GL_CURRENT_TEXTURE_COORDS.
+     *
+     * @param vboIndex Index into ownedVbos array
+     */
+    public void writeDrawRangeRestore(
+        int vboIndex, AccumulatedDraw.RestoreData restoreData
+    ) {
+        ensureCapacity(28);
+        writeInt(GLCommand.DRAW_RANGE_RESTORE);
+        writeInt(vboIndex);
+        writeInt(restoreData.flags);
+        // Last color (4 bytes)
+        writeInt(restoreData.lastColor);
+        // Last normal (4 bytes)
+        writeInt(restoreData.lastNormal);
+        // Last texcoord (2 floats = 8 bytes)
+        writeFloat(restoreData.lastTexCoordU);
+        writeFloat(restoreData.lastTexCoordV);
+    }
+
+
+    public void writeCallList(int listId) {
+        ensureCapacity(8);
+        writeInt(GLCommand.CALL_LIST);
+        writeInt(listId);
+    }
+
+    public void writeBindVBO(int vbo) {
+        ensureCapacity(8);
+        writeInt(GLCommand.BIND_VBO);
+        writeInt(vbo);
+    }
+
+    public void writeBindVAO(int vao) {
+        ensureCapacity(8);
+        writeInt(GLCommand.BIND_VAO);
+        writeInt(vao);
+    }
+
+    public void writeDrawBuffer(int mode) {
+        ensureCapacity(8);
+        writeInt(GLCommand.DRAW_BUFFER);
+        writeInt(mode);
+    }
+
+    private static final int MAX_DRAW_BUFFERS = 8;
+    // cmd (4) + count (4) + buffers (4 * MAX_DRAW_BUFFERS)
+    private static final int DRAW_BUFFERS_SIZE = 4 + 4 + 4 * MAX_DRAW_BUFFERS;
+
+    public void writeDrawBuffers(int count, int buffer) {
+        ensureCapacity(DRAW_BUFFERS_SIZE);
+        writeInt(GLCommand.DRAW_BUFFERS);
+        writeInt(count);
+        writeInt(buffer);
+        for (int i = 1; i < MAX_DRAW_BUFFERS; i++) {
+            writeInt(0);
+        }
+    }
+
+    public void writeDrawBuffers(int count, IntBuffer bufs) {
+        ensureCapacity(DRAW_BUFFERS_SIZE);
+        writeInt(GLCommand.DRAW_BUFFERS);
+        writeInt(count);
+        final int pos = bufs.position();
+        for (int i = 0; i < count && i < MAX_DRAW_BUFFERS; i++) {
+            writeInt(bufs.get(pos + i));
+        }
+        for (int i = count; i < MAX_DRAW_BUFFERS; i++) {
+            writeInt(0);
+        }
+    }
+
+    // === Complex object reference ===
+
+    public void writeComplexCommand(DisplayListCommand cmd) {
+        ensureCapacity(8);
+        final int index = complexObjects.size();
+        complexObjects.add(cmd);
+        writeInt(GLCommand.COMPLEX_REF);
+        writeInt(index);
+    }
+
+    // === Lifecycle ===
+
+    public int size() {
+        return (int) (writePointer - basePointer);
+    }
+
+    public void delete() {
+        for (IndexedDrawCapture c : indexedDraws.getCaptures()) {
+            c.freeBuffers();
+        }
+        for (DisplayListCommand cmd : complexObjects) {
+            cmd.delete();
+        }
+        complexObjects.clear();
+        if (buffer != null) {
+            memFree(buffer);
+            buffer = null;
+        }
+    }
+
+    /**
+     * Deletes every allocated object & returns a ByteBuffer with the capacity equal to its limit.
+     * This CommandRecorder object cannot be used after calling this anymore
+     */
+    public ByteBuffer finish() {
+        for (IndexedDrawCapture c : indexedDraws.getCaptures()) {
+            c.freeBuffers();
+        }
+        final int size = size();
+        buffer.limit(size);
+        final ByteBuffer out = memRealloc(buffer, size);
+        buffer = null;
+        complexObjects.clear();
+        return out;
+    }
+
+    public DisplayListCommand[] getComplexObjects() {
+        return complexObjects.toArray(new DisplayListCommand[complexObjects.size()]);
+    }
+
+    public DisplayListCommand getComplexObject(int index) {
+        return complexObjects.get(index);
+    }
+
+    public boolean isEmpty() {
+        return size() == 0;
+    }
+
+    /**
+     * Clear the buffer for reuse. Does NOT free memory.
+     */
+    public void clear() {
+        writePointer = basePointer;
+        complexObjects.clear();
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/CompiledDisplayList.java

@@ -0,0 +1,165 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizons.angelica.glsm.DisplayListManager;
+import com.gtnewhorizons.angelica.glsm.recording.commands.DisplayListCommand;
+import com.gtnewhorizons.angelica.glsm.recording.commands.IndexedDrawBatch;
+import it.unimi.dsi.fastutil.ints.Int2IntMap;
+import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
+import it.unimi.dsi.fastutil.ints.IntArrayList;
+import it.unimi.dsi.fastutil.ints.IntList;
+
+import java.nio.ByteBuffer;
+import java.util.Collections;
+import java.util.List;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAddress;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memFree;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetInt;
+
+/**
+ * Represents a compiled display list.
+ *
+ * <p>Contains commands serialized to a direct ByteBuffer for off-heap storage,
+ * with complex objects (TexImage2DCmd, TexSubImage2DCmd) stored separately.
+ *
+ * <p>The ownedVbos array contains VBOs that are referenced by DrawRange commands.
+ */
+public final class CompiledDisplayList {
+    /**
+     * Empty display list singleton. Per OpenGL spec, an empty list is still valid.
+     * This instance does nothing when rendered and is never deleted (shared singleton).
+     */
+    public static final CompiledDisplayList EMPTY = new CompiledDisplayList(null, null, null, Collections.emptyList());
+
+    private final ByteBuffer commandBuffer;     // Off-heap command storage, must be freed
+    private final DisplayListCommand[] complexObjects;      // Complex commands (TexImage2D, etc.)
+    private final DisplayListVBO ownedVbos;     // GPU resources referenced by index
+    private final List<IndexedDrawBatch> indexedBatches; // Shared VAO/VBO/EBO triples per layout group
+
+    public CompiledDisplayList(ByteBuffer commandBuffer, DisplayListCommand[] complexObjects, DisplayListVBO ownedVbos, List<IndexedDrawBatch> indexedBatches) {
+        this.commandBuffer = commandBuffer;
+        this.complexObjects = complexObjects;
+        this.ownedVbos = ownedVbos;
+        this.indexedBatches = indexedBatches;
+    }
+
+    /**
+     * Render this display list by executing all commands.
+     */
+    public void render() {
+        render(-1);
+    }
+
+    public void render(int list) {
+        if (commandBuffer != null && commandBuffer.limit() > 0) {
+            CommandBufferExecutor.execute(commandBuffer, complexObjects, ownedVbos, list, this);
+        }
+    }
+
+    /**
+     * Delete all resources held by this display list.
+     */
+    public void delete() {
+        if (complexObjects != null) {
+            for (DisplayListCommand cmd : complexObjects) {
+                cmd.delete();
+            }
+        }
+
+        // Close VBOs from immediate-mode DisplayListVBOBuilder.
+        if (ownedVbos != null) {
+            ownedVbos.delete();
+        }
+
+        // Release shared (VAO, VBO, EBO) triples from IndexedDrawBatchBuilder.
+        if (indexedBatches != null) {
+            for (IndexedDrawBatch batch : indexedBatches) {
+                batch.delete();
+            }
+        }
+
+        // Free the command buffer (off-heap memory)
+        if (commandBuffer != null) {
+            memFree(commandBuffer);
+        }
+    }
+
+    /**
+     * Get the command buffer for debugging/inspection.
+     */
+    public ByteBuffer getCommandBuffer() {
+        return commandBuffer;
+    }
+
+    /**
+     * Get complex objects for inlining into another display list (nested lists).
+     */
+    public DisplayListCommand[] getComplexObjects() {
+        return complexObjects;
+    }
+
+    public DisplayListVBO getOwnedVbos() {
+        return ownedVbos;
+    }
+
+    public List<IndexedDrawBatch> getIndexedBatches() {
+        return indexedBatches;
+    }
+
+    // === Test inspection methods ===
+
+    /**
+     * Get counts of each command type in the buffer.
+     * Used for testing to verify optimization results.
+     */
+    public Int2IntMap getCommandCounts() {
+        final Int2IntMap counts = new Int2IntOpenHashMap();
+        if (commandBuffer == null || commandBuffer.limit() == 0) {
+            return counts;
+        }
+        long ptr = memAddress(commandBuffer);
+        final long end = ptr + commandBuffer.limit();
+        while (ptr < end) {
+            final int cmd = memGetInt(ptr);
+            counts.mergeInt(cmd, 1, Integer::sum);
+            ptr += GLCommand.getCommandSize(cmd, ptr);
+        }
+        return counts;
+    }
+
+    /**
+     * Get the sequence of command opcodes in order.
+     * Used for testing to verify command ordering.
+     */
+    public IntList getCommandOpcodes() {
+        final IntList opcodes = new IntArrayList();
+        if (commandBuffer == null || commandBuffer.limit() == 0) {
+            return opcodes;
+        }
+        long ptr = memAddress(commandBuffer);
+        final long end = ptr + commandBuffer.limit();
+        while (ptr < end) {
+            final int cmd = memGetInt(ptr);
+            opcodes.add(cmd);
+            ptr += GLCommand.getCommandSize(cmd, ptr);
+        }
+        return opcodes;
+    }
+
+    public String getCompiledDisplayListString(int listId, StackTraceElement[] stackTrace) {
+        return DisplayListManager.getCompiledDisplayListString(listId, this, stackTrace);
+    }
+
+    public String toString(int listId, StackTraceElement[] stackTrace) {
+        return getCompiledDisplayListString(listId, stackTrace);
+    }
+
+    public String toString(int listId) {
+        return toString(listId, null);
+    }
+
+    @Override
+    public String toString() {
+        return toString(0);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/DisplayListVBO.java

@@ -0,0 +1,74 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vao.IVertexArrayObject;
+
+/**
+ * A class that stores multiple vertex formats & their corresponding buffers.
+ */
+public final class DisplayListVBO {
+
+    private final SubVBO[] vbos;
+
+    DisplayListVBO(SubVBO[] vbos) {
+        this.vbos = vbos;
+    }
+
+    public void delete() {
+        for (SubVBO vbo : vbos) {
+            vbo.delete();
+        }
+    }
+
+    public SubVBO[] getVBOs() {
+        return vbos;
+    }
+
+    public SubVBO getVBO(int index) {
+        return vbos[index];
+    }
+
+    public void render(int index) {
+        vbos[index].render();
+    }
+
+    public static final class SubVBO {
+
+        private final IVertexArrayObject vao;
+        private final int drawMode;
+        private final int start;
+        private final int count;
+
+        public SubVBO(IVertexArrayObject vao, int drawMode, int start, int count) {
+            this.vao = vao;
+            this.drawMode = drawMode;
+            this.start = start;
+            this.count = count;
+        }
+
+        public int getStart() {
+            return start;
+        }
+
+        public int getCount() {
+            return count;
+        }
+
+        public int getDrawMode() {
+            return drawMode;
+        }
+
+        public void delete() {
+            vao.delete();
+        }
+
+        public void render() {
+            vao.bind();
+            vao.draw(drawMode, start, count);
+            vao.unbind();
+        }
+
+        public IVertexArrayObject getVAO() {
+            return vao;
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/DisplayListVBOBuilder.java

@@ -0,0 +1,137 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vao.IVertexArrayObject;
+import com.gtnewhorizon.gtnhlib.client.renderer.vao.IndexBuffer;
+import com.gtnewhorizon.gtnhlib.client.renderer.vao.IndexedVAO;
+import com.gtnewhorizon.gtnhlib.client.renderer.vao.VAOManager;
+import com.gtnewhorizon.gtnhlib.client.renderer.vbo.IVertexBuffer;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.DefaultVertexFormat;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormat;
+import org.lwjgl.opengl.GL11;
+
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAddress0;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAlloc;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memCopy;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memFree;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.nmemFree;
+
+/**
+ * Compiles multiple ByteBuffers of the same Vertex format into a VBO. Any buffer added to the builder will be freed afterward.
+ */
+public final class DisplayListVBOBuilder {
+
+    // Removes the need for a HashMap. Since it's only an array of 16 values, this should be faster
+    private final List<FormatData>[] formats = new List[VertexFlags.BITSET_SIZE];
+    private int count;
+
+    public DisplayListVBOBuilder addDraw(VertexFormat format, int drawMode, List<ByteBuffer> buffers) {
+        List<FormatData> data = formats[format.getVertexFlags()];
+        if (data == null) {
+            data = new ArrayList<>();
+            formats[format.getVertexFlags()] = data;
+        }
+        data.add(new FormatData(buffers, drawMode, count));
+        count++;
+        return this;
+    }
+
+    public DisplayListVBOBuilder addDraws(List<AccumulatedDraw> draws) {
+        for (AccumulatedDraw draw : draws) {
+            addDraw(draw.format, draw.drawMode, draw.drawBuffers);
+        }
+        return this;
+    }
+
+    public DisplayListVBO build() {
+        final DisplayListVBO.SubVBO[] vbos = new DisplayListVBO.SubVBO[count];
+        final ArrayList<ByteBuffer> allBuffers = new ArrayList<>();
+        for (int i = 0; i < VertexFlags.BITSET_SIZE; i++) {
+            List<FormatData> formatData = formats[i];
+            if (formatData == null) continue;
+            final VertexFormat format = DefaultVertexFormat.ALL_FORMATS[i];
+            int start = 0;
+            final IVertexArrayObject vao = VAOManager.createStorageVAO(format, -1, 0); // drawMode will be ignored
+            final IVertexBuffer vbo = vao.getVBO();
+            for (FormatData data : formatData) {
+                int vertexCount;
+                final List<ByteBuffer> drawBuffers = data.buffers;
+                if (drawBuffers.size() == 1) {
+                    final ByteBuffer buffer = drawBuffers.get(0);
+                    allBuffers.add(buffer);
+                    vertexCount = format.getVertexCount(buffer);
+                } else {
+                    allBuffers.addAll(drawBuffers);
+                    int size = 0;
+                    for (ByteBuffer buffer : drawBuffers) {
+                        size += buffer.limit();
+                    }
+                    vertexCount = format.getVertexCount(size);
+                }
+                if (data.drawMode == GL11.GL_QUADS) {
+                    final IVertexArrayObject indexedVAO = new IndexedVAO(vbo, IndexBuffer.convertQuadsToTrigs(start, start + vertexCount));
+                    vbos[data.drawIndex] = new DisplayListVBO.SubVBO(indexedVAO, GL11.GL_TRIANGLES, 0, vertexCount / 4 * 6);
+                } else if (data.drawMode == GL11.GL_QUAD_STRIP) {
+                    // GL_QUAD_STRIP is removed in core profile; an even-length GL_TRIANGLE_STRIP produces the same quads
+                    vbos[data.drawIndex] = new DisplayListVBO.SubVBO(vao, GL11.GL_TRIANGLE_STRIP, start, vertexCount & ~1);
+                } else if (data.drawMode == GL11.GL_POLYGON) {
+                    // GL_POLYGON is removed in core profile; convert to GL_TRIANGLE_FAN which is equivalent for convex polygons
+                    vbos[data.drawIndex] = new DisplayListVBO.SubVBO(vao, GL11.GL_TRIANGLE_FAN, start, vertexCount);
+                } else {
+                    vbos[data.drawIndex] = new DisplayListVBO.SubVBO(vao, data.drawMode, start, vertexCount);
+                }
+
+
+                start += vertexCount;
+            }
+            ByteBuffer bigBuffer = mergeAndDelete(allBuffers);
+            vbo.allocate(bigBuffer, start);
+            memFree(bigBuffer);
+
+            allBuffers.clear();
+        }
+        return new DisplayListVBO(vbos);
+    }
+
+    private static ByteBuffer mergeAndDelete(List<ByteBuffer> buffers) {
+        if (buffers.size() == 1) {
+            return buffers.get(0);
+        }
+        int needed = 0;
+        for (ByteBuffer buffer : buffers) {
+            needed += buffer.remaining();
+        }
+
+        ByteBuffer out = memAlloc(needed);
+        long dst = memAddress0(out);
+
+        for (ByteBuffer buffer : buffers) {
+            final int len = buffer.limit();
+            final long address = memAddress0(buffer);
+            memCopy(address, dst, len);
+            dst += len;
+
+            nmemFree(address);
+        }
+
+        out.limit(needed);
+        return out;
+    }
+
+    private static final class FormatData {
+
+        private final List<ByteBuffer> buffers;
+        private final int drawMode;
+        private final int drawIndex;
+
+        public FormatData(List<ByteBuffer> buffers, int drawMode, int drawIndex) {
+            this.buffers = buffers;
+            this.drawMode = drawMode;
+            this.drawIndex = drawIndex;
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/GLCommand.java

@@ -0,0 +1,252 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetInt;
+
+/**
+ * Command opcodes for ByteBuffer-based display list serialization.
+ * Each command has a fixed layout described in comments.
+ * All values are 4-byte aligned.
+ */
+public final class GLCommand {
+    private GLCommand() {}
+
+    // === Single int commands (8 bytes: opcode + param) ===
+    public static final int ENABLE = 1;              // [cmd:4][cap:4]
+    public static final int DISABLE = 2;             // [cmd:4][cap:4]
+    public static final int CLEAR = 3;               // [cmd:4][mask:4]
+    public static final int CLEAR_STENCIL = 4;       // [cmd:4][s:4]
+    public static final int CULL_FACE = 5;           // [cmd:4][mode:4]
+    public static final int DEPTH_FUNC = 6;          // [cmd:4][func:4]
+    public static final int SHADE_MODEL = 7;         // [cmd:4][mode:4]
+    public static final int LOGIC_OP = 8;            // [cmd:4][opcode:4]
+    public static final int MATRIX_MODE = 9;         // [cmd:4][mode:4]
+    public static final int ACTIVE_TEXTURE = 10;     // [cmd:4][texture:4]
+    public static final int USE_PROGRAM = 11;        // [cmd:4][program:4]
+    public static final int PUSH_ATTRIB = 12;        // [cmd:4][mask:4]
+    public static final int POP_ATTRIB = 13;         // [cmd:4][unused:4]
+    public static final int LOAD_IDENTITY = 14;      // [cmd:4][matrixMode:4]
+    public static final int PUSH_MATRIX = 15;        // [cmd:4][matrixMode:4]
+    public static final int POP_MATRIX = 16;         // [cmd:4][matrixMode:4]
+    public static final int STENCIL_MASK = 17;       // [cmd:4][mask:4]
+    public static final int DEPTH_MASK = 18;         // [cmd:4][flag:4] (0 or 1)
+    public static final int FRONT_FACE = 19;         // [cmd:4][mode:4]
+
+    // === Two int commands (12 bytes) ===
+    public static final int BIND_TEXTURE = 20;       // [cmd:4][target:4][texture:4]
+    public static final int POLYGON_MODE = 21;       // [cmd:4][face:4][mode:4]
+    public static final int COLOR_MATERIAL = 22;     // [cmd:4][face:4][mode:4]
+    public static final int LINE_STIPPLE = 23;       // [cmd:4][factor:4][pattern:4]
+    public static final int STENCIL_MASK_SEPARATE = 24; // [cmd:4][face:4][mask:4]
+    public static final int FOGI = 25;               // [cmd:4][pname:4][param:4]
+    public static final int HINT = 26;               // [cmd:4][target:4][mode:4]
+
+    // === Three int commands (16 bytes) ===
+    public static final int STENCIL_FUNC = 30;       // [cmd:4][func:4][ref:4][mask:4]
+    public static final int STENCIL_OP = 31;         // [cmd:4][fail:4][zfail:4][zpass:4]
+    public static final int TEX_PARAMETERI = 32;     // [cmd:4][target:4][pname:4][param:4]
+
+    // === Four int commands (20 bytes) ===
+    public static final int VIEWPORT = 40;           // [cmd:4][x:4][y:4][width:4][height:4]
+    public static final int BLEND_FUNC = 41;         // [cmd:4][srcRgb:4][dstRgb:4][srcAlpha:4][dstAlpha:4]
+    public static final int COLOR_MASK = 42;         // [cmd:4][r:4][g:4][b:4][a:4] (0 or 1 each)
+    public static final int STENCIL_FUNC_SEPARATE = 43; // [cmd:4][face:4][func:4][ref:4][mask:4]
+    public static final int STENCIL_OP_SEPARATE = 44; // [cmd:4][face:4][sfail:4][dpfail:4][dppass:4]
+    public static final int SCISSOR = 45;             // [cmd:4][x:4][y:4][width:4][height:4]
+
+    // === Float commands ===
+    public static final int POINT_SIZE = 50;         // [cmd:4][size:4f]
+    public static final int LINE_WIDTH = 51;         // [cmd:4][width:4f]
+    public static final int POLYGON_OFFSET = 52;     // [cmd:4][factor:4f][units:4f]
+    public static final int NORMAL = 53;             // [cmd:4][x:4f][y:4f][z:4f]
+    public static final int COLOR = 54;              // [cmd:4][r:4f][g:4f][b:4f][a:4f]
+    public static final int CLEAR_COLOR = 55;        // [cmd:4][r:4f][g:4f][b:4f][a:4f]
+    public static final int BLEND_COLOR = 56;        // [cmd:4][r:4f][g:4f][b:4f][a:4f]
+
+    // === Mixed int+float commands ===
+    public static final int ALPHA_FUNC = 60;         // [cmd:4][func:4][ref:4f]
+    public static final int FOGF = 61;               // [cmd:4][pname:4][param:4f]
+    public static final int LIGHTF = 62;             // [cmd:4][light:4][pname:4][param:4f]
+    public static final int LIGHT_MODELF = 63;       // [cmd:4][pname:4][param:4f]
+    public static final int LIGHTI = 64;             // [cmd:4][light:4][pname:4][param:4]
+    public static final int LIGHT_MODELI = 65;       // [cmd:4][pname:4][param:4]
+    public static final int MATERIALF = 66;          // [cmd:4][face:4][pname:4][param:4f]
+    public static final int TEX_PARAMETERF = 67;     // [cmd:4][target:4][pname:4][param:4f]
+
+    // === Double commands ===
+    public static final int TRANSLATE = 70;          // [cmd:4][mode:4][x:8d][y:8d][z:8d] = 32 bytes
+    public static final int SCALE = 72;              // [cmd:4][mode:4][x:8d][y:8d][z:8d] = 32 bytes
+    public static final int CLEAR_DEPTH = 75;        // [cmd:4][depth:8d] = 12 bytes
+
+    // === Matrix commands (72 bytes) ===
+    public static final int MULT_MATRIX = 80;        // [cmd:4][mode:4][m00-m33:64f] = 72 bytes
+    public static final int LOAD_MATRIX = 81;        // [cmd:4][mode:4][m00-m33:64f] = 72 bytes
+
+    // === Buffer commands (inline 4 floats max) ===
+    public static final int FOG = 90;                // [cmd:4][pname:4][count:4][params:16f] = 28 bytes
+    public static final int LIGHT = 91;              // [cmd:4][light:4][pname:4][count:4][params:16f] = 32 bytes
+    public static final int LIGHT_MODEL = 92;        // [cmd:4][pname:4][count:4][params:16f] = 28 bytes
+    public static final int MATERIAL = 93;           // [cmd:4][face:4][pname:4][count:4][params:16f] = 32 bytes
+    public static final int CLIP_PLANE = 94;         // [cmd:4][plane:4][a:8d][b:8d][c:8d][d:8d] = 40 bytes
+
+    // === Draw commands ===
+    public static final int DRAW_RANGE = 100;        // [cmd:4][vboIndex:4] = 8 bytes
+    public static final int DRAW_RANGE_RESTORE = 101; // [cmd:4][vboIndex:4][flags:4][color:4][normal:4][lastTexCoord:8f] = 28 bytes
+    public static final int CALL_LIST = 102;         // [cmd:4][listId:4] = 8 bytes
+
+
+    public static final int DRAW_BUFFER = 112;       // [cmd:4][mode:4] = 8 bytes
+    public static final int DRAW_BUFFERS = 113;      // [cmd:4][count:4][bufs:4*8] = 40 bytes (up to 8 buffers)
+    /**
+     * Draw VBO range with attribute restoration after draw.
+     * Used for immediate mode VBOs to restore GL current state (color, normal, texcoord).
+     */
+
+
+    // === Bind commands ===
+    public static final int BIND_VBO = 120;
+    public static final int BIND_VAO = 121;
+
+    // === Complex object reference ===
+    public static final int COMPLEX_REF = 255;       // [cmd:4][index:4] = 8 bytes
+
+    /**
+     * Get a human-readable name for an opcode (for debugging).
+     */
+    public static String getName(int opcode) {
+        return switch (opcode) {
+            case ENABLE -> "ENABLE";
+            case DISABLE -> "DISABLE";
+            case CLEAR -> "CLEAR";
+            case CLEAR_STENCIL -> "CLEAR_STENCIL";
+            case CULL_FACE -> "CULL_FACE";
+            case DEPTH_FUNC -> "DEPTH_FUNC";
+            case SHADE_MODEL -> "SHADE_MODEL";
+            case LOGIC_OP -> "LOGIC_OP";
+            case MATRIX_MODE -> "MATRIX_MODE";
+            case ACTIVE_TEXTURE -> "ACTIVE_TEXTURE";
+            case USE_PROGRAM -> "USE_PROGRAM";
+            case PUSH_ATTRIB -> "PUSH_ATTRIB";
+            case POP_ATTRIB -> "POP_ATTRIB";
+            case LOAD_IDENTITY -> "LOAD_IDENTITY";
+            case PUSH_MATRIX -> "PUSH_MATRIX";
+            case POP_MATRIX -> "POP_MATRIX";
+            case STENCIL_MASK -> "STENCIL_MASK";
+            case DEPTH_MASK -> "DEPTH_MASK";
+            case FRONT_FACE -> "FRONT_FACE";
+            case BIND_TEXTURE -> "BIND_TEXTURE";
+            case POLYGON_MODE -> "POLYGON_MODE";
+            case COLOR_MATERIAL -> "COLOR_MATERIAL";
+            case LINE_STIPPLE -> "LINE_STIPPLE";
+            case STENCIL_MASK_SEPARATE -> "STENCIL_MASK_SEPARATE";
+            case FOGI -> "FOGI";
+            case HINT -> "HINT";
+            case STENCIL_FUNC -> "STENCIL_FUNC";
+            case STENCIL_OP -> "STENCIL_OP";
+            case TEX_PARAMETERI -> "TEX_PARAMETERI";
+            case VIEWPORT -> "VIEWPORT";
+            case SCISSOR -> "SCISSOR";
+            case BLEND_FUNC -> "BLEND_FUNC";
+            case COLOR_MASK -> "COLOR_MASK";
+            case STENCIL_FUNC_SEPARATE -> "STENCIL_FUNC_SEPARATE";
+            case STENCIL_OP_SEPARATE -> "STENCIL_OP_SEPARATE";
+            case POINT_SIZE -> "POINT_SIZE";
+            case LINE_WIDTH -> "LINE_WIDTH";
+            case POLYGON_OFFSET -> "POLYGON_OFFSET";
+            case COLOR -> "COLOR";
+            case CLEAR_COLOR -> "CLEAR_COLOR";
+            case BLEND_COLOR -> "BLEND_COLOR";
+            case ALPHA_FUNC -> "ALPHA_FUNC";
+            case FOGF -> "FOGF";
+            case LIGHTF -> "LIGHTF";
+            case LIGHT_MODELF -> "LIGHT_MODELF";
+            case LIGHTI -> "LIGHTI";
+            case LIGHT_MODELI -> "LIGHT_MODELI";
+            case MATERIALF -> "MATERIALF";
+            case TEX_PARAMETERF -> "TEX_PARAMETERF";
+            case TRANSLATE -> "TRANSLATE";
+            case SCALE -> "SCALE";
+            case CLEAR_DEPTH -> "CLEAR_DEPTH";
+            case MULT_MATRIX -> "MULT_MATRIX";
+            case LOAD_MATRIX -> "LOAD_MATRIX";
+            case FOG -> "FOG";
+            case LIGHT -> "LIGHT";
+            case LIGHT_MODEL -> "LIGHT_MODEL";
+            case MATERIAL -> "MATERIAL";
+            case CLIP_PLANE -> "CLIP_PLANE";
+            case DRAW_RANGE -> "DRAW_RANGE";
+            case CALL_LIST -> "CALL_LIST";
+            case DRAW_BUFFER -> "DRAW_BUFFER";
+            case DRAW_BUFFERS -> "DRAW_BUFFERS";
+            case COMPLEX_REF -> "COMPLEX_REF";
+            case DRAW_RANGE_RESTORE -> "DRAW_RANGE_RESTORE";
+            case BIND_VAO -> "BIND_VAO";
+            case BIND_VBO -> "BIND_VBO";
+            default -> "UNKNOWN(" + opcode + ")";
+        };
+    }
+
+    /**
+     * Get size of a command in bytes (including the opcode).
+     */
+    public static int getCommandSize(int cmd, long ptr) {
+        return switch (cmd) {
+            // Opcode-only commands (4 bytes)
+            case GLCommand.LOAD_IDENTITY, GLCommand.PUSH_MATRIX, GLCommand.POP_MATRIX -> 4;
+
+            // Single int commands (8 bytes)
+            case GLCommand.ENABLE, GLCommand.DISABLE, GLCommand.CLEAR, GLCommand.CLEAR_STENCIL,
+                 GLCommand.CULL_FACE, GLCommand.DEPTH_FUNC, GLCommand.SHADE_MODEL, GLCommand.LOGIC_OP,
+                 GLCommand.MATRIX_MODE, GLCommand.ACTIVE_TEXTURE, GLCommand.USE_PROGRAM,
+                 GLCommand.PUSH_ATTRIB, GLCommand.POP_ATTRIB, GLCommand.STENCIL_MASK,
+                 GLCommand.DEPTH_MASK, GLCommand.FRONT_FACE, GLCommand.POINT_SIZE, GLCommand.LINE_WIDTH,
+                 GLCommand.CALL_LIST, GLCommand.COMPLEX_REF, GLCommand.DRAW_RANGE, GLCommand.BIND_VBO,
+                 GLCommand.BIND_VAO -> 8;
+
+            // Two int commands (12 bytes)
+            case GLCommand.BIND_TEXTURE, GLCommand.POLYGON_MODE, GLCommand.COLOR_MATERIAL,
+                 GLCommand.LINE_STIPPLE, GLCommand.STENCIL_MASK_SEPARATE, GLCommand.FOGI,
+                 GLCommand.HINT, GLCommand.POLYGON_OFFSET, GLCommand.ALPHA_FUNC, GLCommand.FOGF,
+                 GLCommand.LIGHT_MODELF, GLCommand.LIGHT_MODELI -> 12;
+
+            // Three int commands (16 bytes)
+            case GLCommand.STENCIL_FUNC, GLCommand.STENCIL_OP, GLCommand.TEX_PARAMETERI,
+                 GLCommand.LIGHTF, GLCommand.LIGHTI,
+                 GLCommand.MATERIALF, GLCommand.TEX_PARAMETERF -> 16;
+
+            // Four int commands (20 bytes)
+            case GLCommand.VIEWPORT, GLCommand.BLEND_FUNC, GLCommand.COLOR_MASK,
+                 GLCommand.STENCIL_FUNC_SEPARATE, GLCommand.STENCIL_OP_SEPARATE,
+                 GLCommand.SCISSOR,
+                 GLCommand.COLOR, GLCommand.CLEAR_COLOR, GLCommand.BLEND_COLOR -> 20;
+
+            // DRAW_RANGE_RESTORE: 28 bytes
+            case GLCommand.DRAW_RANGE_RESTORE -> 28;
+
+            // DRAW_BUFFER: 8 bytes [cmd:4][mode:4]
+            case GLCommand.DRAW_BUFFER -> 8;
+
+            // DRAW_BUFFERS: 40 bytes [cmd:4][count:4][bufs:4*8]
+            case GLCommand.DRAW_BUFFERS -> 40;
+
+            // Double commands
+            case GLCommand.TRANSLATE, GLCommand.SCALE -> 16;  // cmd + 3 floats
+            case GLCommand.CLEAR_DEPTH -> 12;  // cmd + 1 double
+
+            // Matrix commands
+            case GLCommand.MULT_MATRIX, GLCommand.LOAD_MATRIX -> 68;  // cmd + 16 floats
+
+            // Buffer commands (variable, read count)
+            case GLCommand.FOG, GLCommand.LIGHT_MODEL -> {
+                final int count = memGetInt(ptr + 8);  // pname at +4, count at +8
+                yield 12 + count * 4;
+            }
+            case GLCommand.LIGHT, GLCommand.MATERIAL -> {
+                final int count = memGetInt(ptr + 12);  // light/face at +4, pname at +8, count at +12
+                yield 16 + count * 4;
+            }
+            case GLCommand.CLIP_PLANE -> 40;  // cmd + plane + 4 doubles
+
+            default -> throw new IllegalStateException("Unknown command: " + cmd);
+        };
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/ImmediateModeRecorder.java

@@ -0,0 +1,342 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.CallbackTessellator;
+import com.gtnewhorizon.gtnhlib.client.renderer.DirectTessellator;
+import com.gtnewhorizon.gtnhlib.client.renderer.TessellatorManager;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement.Usage;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.ffp.VAOManager;
+import org.lwjgl.opengl.GL11;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
+
+/**
+ * Records immediate mode GL calls (glBegin/glEnd/glVertex) via {@link DirectTessellator}.
+ * Used both during display list compilation and for live immediate mode emulation in core profile.
+ */
+public final class ImmediateModeRecorder {
+    private static final CallbackTessellator tessellator = new CallbackTessellator(TessellatorManager.DEFAULT_BUFFER_SIZE);
+
+    private record ThreadTessellator(Thread thread, DirectTessellator tessellator) {}
+
+    private static final Queue<ThreadTessellator> threadTessellators = new ConcurrentLinkedQueue<>();
+    private static final ThreadLocal<DirectTessellator> threadTessellator = ThreadLocal.withInitial(() -> {
+        final DirectTessellator t = new DirectTessellator(TessellatorManager.DEFAULT_BUFFER_SIZE);
+        threadTessellators.add(new ThreadTessellator(Thread.currentThread(), t));
+        cleanupOrphanTessellators();
+        return t;
+    });
+
+    private ImmediateModeRecorder() {
+
+    }
+
+    public static int getThreadTessellatorCount() {
+        return threadTessellators.size();
+    }
+
+    public static synchronized void cleanupOrphanTessellators() {
+        threadTessellators.removeIf(tt -> {
+            if (tt.thread().isAlive()) return false;
+            tt.tessellator().delete();
+            return true;
+        });
+    }
+
+    private static DirectTessellator tessellator() {
+        if (Thread.currentThread() == GLStateManager.getMainThread()) {
+            return tessellator;
+        }
+        return threadTessellator.get();
+    }
+
+    public static DirectTessellator getInternalTessellator() {
+        return tessellator();
+    }
+
+    public static boolean isDrawing() {
+        return tessellator().isDrawing;
+    }
+
+    /**
+     * Set the current texture coordinate.
+     * Called by GLStateManager.glTexCoord*.
+     */
+    public static void setTexCoord(float s, float t) {
+        tessellator().setTextureUV(s, t);
+    }
+
+    /**
+     * Set the current lightmap coordinate as packed brightness.
+     * Called by GLStateManager.glMultiTexCoord2f for unit 1 during recording/drawing.
+     */
+    public static void setLightmapCoord(float s, float t) {
+        tessellator().setBrightness(((int) t << 16) | ((int) s & 0xFFFF));
+    }
+
+    /**
+     * Set the current normal vector.
+     * Called by GLStateManager.glNormal*.
+     */
+    public static void setNormal(float x, float y, float z) {
+        tessellator().setNormal(x, y, z);
+    }
+
+    /**
+     * Set the current color on the internal tessellator.
+     * Called by GLStateManager.glColor* when inside a glBegin/glEnd block.
+     */
+    public static void setColor(float r, float g, float b, float a) {
+        tessellator().setColorRGBA((int) (r * 255.0f), (int) (g * 255.0f), (int) (b * 255.0f), (int) (a * 255.0f));
+    }
+
+    /**
+     * Start recording a new primitive.
+     * Resets the tessellator to clear any data from the previous draw.
+     *
+     * @param primitiveType GL primitive type (GL_QUADS, GL_TRIANGLES, etc.)
+     */
+    public static void begin(int primitiveType) {
+        final DirectTessellator t = tessellator();
+        t.reset();
+        t.startDrawing(primitiveType);
+    }
+
+    /**
+     * Start recording a new primitive with initial color sync from GLSM cache.
+     * Used for live immediate mode emulation only (not display list recording).
+     */
+    public static void beginLive(int primitiveType) {
+        final DirectTessellator t = tessellator();
+        t.reset();
+        t.startDrawing(primitiveType);
+        final var c = GLStateManager.getColor();
+        t.setColorRGBA((int) (c.getRed() * 255.0f), (int) (c.getGreen() * 255.0f), (int) (c.getBlue() * 255.0f), (int) (c.getAlpha() * 255.0f));
+    }
+
+    /**
+     * End the current primitive, convert to quads/lines, and return them immediately.
+     * This allows the caller to create AccumulatedDraw at the correct command position.
+     *
+     * @return Result containing quads, lines, and flags, or null if no geometry was produced
+     */
+    public static DirectTessellator end() {
+        final DirectTessellator t = tessellator();
+        if (!t.isDrawing) {
+            throw new IllegalStateException("glEnd called without glBegin");
+        }
+
+        t.isDrawing = false;
+
+        if (t.isEmpty()) return null;
+
+        return t;
+    }
+
+    /**
+     * Record a vertex with current attributes.
+     * Color is read from GLStateManager at call time.
+     */
+    public static void vertex(float x, float y, float z) {
+        final DirectTessellator t = tessellator();
+        if (!t.isDrawing) {
+            throw new IllegalStateException("glVertex called outside glBegin/glEnd");
+        }
+        t.addVertex(x, y, z);
+    }
+
+    /**
+     * Check if any immediate mode geometry has been captured.
+     *
+     * <p>Note: With immediate flush mode, this will typically return false as geometry
+     * is returned from end() immediately. This method is kept for edge cases
+     * where primitives might fail to convert (e.g., incomplete quads).
+     */
+    public static boolean hasGeometry() {
+        return tessellator().vertexCount != 0;
+    }
+
+    /**
+     * Reset all state including current texcoord/normal.
+     * Called when starting a new display list.
+     */
+    public static void reset() {
+        tessellator().reset();
+    }
+
+    private static final int LOC_POSITION = Usage.POSITION.getAttributeLocation();
+    private static final int LOC_COLOR = Usage.COLOR.getAttributeLocation();
+    private static final int LOC_UV0 = Usage.PRIMARY_UV.getAttributeLocation();
+    private static final int LOC_UV1 = Usage.SECONDARY_UV.getAttributeLocation();
+    private static final int LOC_NORMAL = Usage.NORMAL.getAttributeLocation();
+    private static final int NUM_ATTRIBS = 1 + Arrays.stream(Usage.values())
+        .mapToInt(Usage::getAttributeLocation)
+            .max().orElse(0);
+
+    private static final class AttribReader {
+        ByteBuffer data;
+        int stride;
+        int baseOffset;
+        int size;
+        int loc;
+        int type;
+        boolean normalized;
+    }
+
+    private static final AttribReader[] readers = new AttribReader[NUM_ATTRIBS];
+    private static int nonPositionCount;
+    private static final int[] nonPositionIndices = new int[NUM_ATTRIBS - 1];
+    private static int positionReaderIndex = -1;
+
+    static {
+        for (int i = 0; i < NUM_ATTRIBS; i++) {
+            readers[i] = new AttribReader();
+        }
+    }
+
+    /**
+     * Process a glDrawArrays call during display list recording.
+     * Reads vertex data from VBOs or client memory referenced by VertexAttribState and converts to immediate mode geometry.
+     */
+    public static DirectTessellator processDrawArraysFromAttribs(int mode, int first, int count) {
+        final AttribSnapshot snap = AttribSnapshot.snapshot(first, count);
+        try {
+            prepareReaders(snap);
+            if (positionReaderIndex < 0) return null;
+            return readVerticesFromBuffer(mode, first, count);
+        } finally {
+            snap.free();
+        }
+    }
+
+    private static void prepareReaders(AttribSnapshot snap) {
+        nonPositionCount = 0;
+        positionReaderIndex = -1;
+
+        for (int i = 0; i < NUM_ATTRIBS; i++) {
+            final AttribSnapshot.AttribDesc d = snap.get(i);
+            if (d == null) continue;
+
+            final AttribReader r = readers[i];
+            r.data = d.readBuffer();
+            r.stride = d.effectiveStride();
+            r.baseOffset = (int) (d.offset() - d.readBufferBaseOffset());
+            r.size = d.size();
+            r.loc = i;
+            r.type = d.type();
+            r.normalized = d.normalized();
+
+            if (i == LOC_POSITION) {
+                positionReaderIndex = i;
+            } else {
+                nonPositionIndices[nonPositionCount++] = i;
+            }
+        }
+    }
+
+    private static DirectTessellator readVerticesFromBuffer(int mode, int first, int count) {
+        begin(mode);
+        final DirectTessellator t = tessellator();
+
+        for (int i = first; i < first + count; i++) {
+            readVertexFromBuffer(t, i);
+        }
+
+        return end();
+    }
+
+    public static int readIndex(ByteBuffer ebo, int indexType, int eboOffset, int i) {
+        return switch (indexType) {
+            case GL11.GL_UNSIGNED_BYTE -> ebo.get(eboOffset + i) & 0xFF;
+            case GL11.GL_UNSIGNED_SHORT -> ebo.getShort(eboOffset + i * 2) & 0xFFFF;
+            case GL11.GL_UNSIGNED_INT -> ebo.getInt(eboOffset + i * 4);
+            default -> i;
+        };
+    }
+
+    private static void readVertexFromBuffer(DirectTessellator t, int vertexIndex) {
+        for (int i = 0; i < nonPositionCount; i++) {
+            final AttribReader r = readers[nonPositionIndices[i]];
+            final int base = r.baseOffset + vertexIndex * r.stride;
+            emitAttrib(t, r, base);
+        }
+
+        if (positionReaderIndex >= 0) {
+            final AttribReader r = readers[positionReaderIndex];
+            final int base = r.baseOffset + vertexIndex * r.stride;
+            t.addVertex(
+                readComponent(r, base, 0),
+                readComponent(r, base, 1),
+                (r.size >= 3) ? readComponent(r, base, 2) : 0.0f);
+        }
+    }
+
+    private static void emitAttrib(DirectTessellator t, AttribReader r, int base) {
+        if (r.loc == LOC_NORMAL) {
+            t.setNormal(
+                readComponent(r, base, 0),
+                readComponent(r, base, 1),
+                readComponent(r, base, 2));
+        } else if (r.loc == LOC_UV0) {
+            t.setTextureUV(
+                readComponent(r, base, 0),
+                (r.size >= 2) ? readComponent(r, base, 1) : 0.0f);
+        } else if (r.loc == LOC_UV1) {
+            if (r.type == GL11.GL_SHORT) {
+                final int s = r.data.getShort(base) & 0xFFFF;
+                final int u = (r.size >= 2) ? (r.data.getShort(base + 2) & 0xFFFF) : 0;
+                t.setBrightness((u << 16) | s);
+            } else if (r.type == GL11.GL_FLOAT) {
+                final int s = (int) r.data.getFloat(base);
+                final int u = (r.size >= 2) ? (int) r.data.getFloat(base + 4) : 0;
+                t.setBrightness((u << 16) | (s & 0xFFFF));
+            }
+        } else if (r.loc == LOC_COLOR) {
+            final float cr = readComponent(r, base, 0);
+            final float cg = readComponent(r, base, 1);
+            final float cb = readComponent(r, base, 2);
+            final float ca = (r.size >= 4) ? readComponent(r, base, 3) : 1.0f;
+            t.setColorRGBA((int) (cr * 255.0f), (int) (cg * 255.0f), (int) (cb * 255.0f), (int) (ca * 255.0f));
+        }
+    }
+
+    private static float readComponent(AttribReader r, int base, int component) {
+        return VAOManager.Attrib.readComponent(r.type, r.normalized, r.data, base, component);
+    }
+
+    public static float readComponent(int type, boolean normalized, ByteBuffer buf, int base, int component) {
+        return switch (type) {
+            case GL11.GL_FLOAT -> buf.getFloat(base + component * 4);
+            case GL11.GL_DOUBLE -> (float) buf.getDouble(base + component * 8);
+            case GL11.GL_INT -> {
+                final int v = buf.getInt(base + component * 4);
+                yield normalized ? v / (float) Integer.MAX_VALUE : (float) v;
+            }
+            case GL11.GL_UNSIGNED_INT -> {
+                final int v = buf.getInt(base + component * 4);
+                yield normalized ? (v & 0xFFFFFFFFL) / (float) 0xFFFFFFFFL : (float) (v & 0xFFFFFFFFL);
+            }
+            case GL11.GL_SHORT -> {
+                final short v = buf.getShort(base + component * 2);
+                yield normalized ? v / (float) Short.MAX_VALUE : (float) v;
+            }
+            case GL11.GL_UNSIGNED_SHORT -> {
+                final int v = buf.getShort(base + component * 2) & 0xFFFF;
+                yield normalized ? v / (float) 0xFFFF : (float) v;
+            }
+            case GL11.GL_BYTE -> {
+                final byte v = buf.get(base + component);
+                yield normalized ? v / 127.0f : (float) v;
+            }
+            case GL11.GL_UNSIGNED_BYTE -> {
+                final int v = buf.get(base + component) & 0xFF;
+                yield normalized ? v / 255.0f : (float) v;
+            }
+            default -> 0.0f;
+        };
+    }
+
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/commands/AttribLayoutKey.java

@@ -0,0 +1,64 @@
+package com.gtnewhorizons.angelica.glsm.recording.commands;
+
+import com.gtnewhorizons.angelica.glsm.ffp.VAOManager;
+
+import java.util.Arrays;
+
+public final class AttribLayoutKey {
+    final int[] locations;
+    final int[] sizes;
+    final int[] types;
+    final boolean[] normalized;
+    private final int[] offsets;
+    private final int stride;
+    private final int hash;
+
+    public AttribLayoutKey(int[] locations, int[] sizes, int[] types, boolean[] normalized) {
+        this.locations = locations;
+        this.sizes = sizes;
+        this.types = types;
+        this.normalized = normalized;
+
+        final int n = locations.length;
+        final int[] off = new int[n];
+        int base = 0;
+        int maxAlign = 1;
+        for (int i = 0; i < n; i++) {
+            final int typeSize = VAOManager.Attrib.glTypeSizeBytes(types[i]);
+            if (typeSize > maxAlign) maxAlign = typeSize;
+            base = (base + typeSize - 1) & -typeSize;
+            off[i] = base;
+            base += sizes[i] * typeSize;
+        }
+        this.offsets = off;
+        this.stride = (base + maxAlign - 1) & -maxAlign;
+
+        int h = Arrays.hashCode(locations);
+        h = 31 * h + Arrays.hashCode(sizes);
+        h = 31 * h + Arrays.hashCode(types);
+        h = 31 * h + Arrays.hashCode(normalized);
+        this.hash = h;
+    }
+
+    public int offset(int i) {
+        return offsets[i];
+    }
+
+    public int stride() {
+        return stride;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (!(o instanceof AttribLayoutKey k)) return false;
+        return Arrays.equals(locations, k.locations)
+            && Arrays.equals(sizes, k.sizes)
+            && Arrays.equals(types, k.types)
+            && Arrays.equals(normalized, k.normalized);
+    }
+
+    @Override
+    public int hashCode() {
+        return hash;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/commands/BatchedIndexedDrawCmd.java

@@ -0,0 +1,37 @@
+package com.gtnewhorizons.angelica.glsm.recording.commands;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+
+public final class BatchedIndexedDrawCmd implements DisplayListCommand {
+    private int sharedVAO;
+    private int drawMode;
+    private int indexCount;
+    private int indexType;
+    private long indexByteOffset;
+
+    public void fill(int sharedVAO, int drawMode, int indexCount, int indexType, long indexByteOffset) {
+        this.sharedVAO = sharedVAO;
+        this.drawMode = drawMode;
+        this.indexCount = indexCount;
+        this.indexType = indexType;
+        this.indexByteOffset = indexByteOffset;
+    }
+
+    public int getSharedVAO() { return sharedVAO; }
+    public int getDrawMode() { return drawMode; }
+    public int getIndexCount() { return indexCount; }
+    public int getIndexType() { return indexType; }
+    public long getIndexByteOffset() { return indexByteOffset; }
+
+    @Override
+    public void execute() {
+        if (sharedVAO == 0) return;
+        GLStateManager.glBindVertexArray(sharedVAO);
+        GLStateManager.glDrawElements(drawMode, indexCount, indexType, indexByteOffset);
+    }
+
+    @Override
+    public String toString() {
+        return "BatchedIndexedDrawCmd(vao=" + sharedVAO + ", mode=" + drawMode + ", count=" + indexCount + ", type=" + indexType + ", offset=" + indexByteOffset + ")";
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/commands/DisplayListCommand.java

@@ -0,0 +1,20 @@
+package com.gtnewhorizons.angelica.glsm.recording.commands;
+
+/**
+ * A single command recorded during display list compilation.
+ * Commands are executed in sequence during glCallList() to replay the display list.
+ */
+public interface DisplayListCommand {
+    /**
+     * Execute this command by calling the appropriate GL function.
+     */
+    void execute();
+
+    /**
+     * Release any resources held by this command (e.g., VBOs).
+     * Called when the display list is deleted.
+     */
+    default void delete() {
+        // Most commands don't hold resources
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/commands/IndexedDrawBatch.java

@@ -0,0 +1,34 @@
+package com.gtnewhorizons.angelica.glsm.recording.commands;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+
+public final class IndexedDrawBatch {
+    private int sharedVAO;
+    private int sharedVBO;
+    private int sharedEBO;
+    private boolean deleted;
+
+    public IndexedDrawBatch(int sharedVAO, int sharedVBO, int sharedEBO) {
+        this.sharedVAO = sharedVAO;
+        this.sharedVBO = sharedVBO;
+        this.sharedEBO = sharedEBO;
+    }
+
+    public int getSharedVAO() { return sharedVAO; }
+    public int getSharedVBO() { return sharedVBO; }
+    public int getSharedEBO() { return sharedEBO; }
+
+    public void delete() {
+        if (deleted) return;
+        deleted = true;
+        if (sharedVAO != 0) GLStateManager.glDeleteVertexArrays(sharedVAO);
+        if (sharedVBO != 0) GLStateManager.glDeleteBuffers(sharedVBO);
+        if (sharedEBO != 0) GLStateManager.glDeleteBuffers(sharedEBO);
+        sharedVAO = sharedVBO = sharedEBO = 0;
+    }
+
+    @Override
+    public String toString() {
+        return "IndexedDrawBatch(vao=" + sharedVAO + ", vbo=" + sharedVBO + ", ebo=" + sharedEBO + ")";
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/commands/IndexedDrawBatchBuilder.java

@@ -0,0 +1,171 @@
+package com.gtnewhorizons.angelica.glsm.recording.commands;
+
+import com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import it.unimi.dsi.fastutil.objects.Object2ObjectLinkedOpenHashMap;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAddress0;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memCopy;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetInt;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutInt;
+
+public final class IndexedDrawBatchBuilder {
+
+    private final List<IndexedDrawCapture> captures = new ArrayList<>();
+
+    public boolean isEmpty() {
+        return captures.isEmpty();
+    }
+
+    public void add(IndexedDrawCapture capture) {
+        captures.add(capture);
+    }
+
+    public List<IndexedDrawCapture> getCaptures() {
+        return captures;
+    }
+
+    public List<IndexedDrawBatch> build() {
+        final List<IndexedDrawBatch> out = new ArrayList<>();
+        if (captures.isEmpty()) return out;
+
+        final int prevVAO = GLStateManager.getBoundVAO();
+        final int prevVBO = GLStateManager.getBoundVBO();
+        final int prevEBO = GLStateManager.getBoundEBO();
+
+        final List<GroupResult> results = new ArrayList<>();
+        boolean success = false;
+        try {
+            final Object2ObjectLinkedOpenHashMap<AttribLayoutKey, List<IndexedDrawCapture>> groups = new Object2ObjectLinkedOpenHashMap<>();
+            for (IndexedDrawCapture c : captures) {
+                groups.computeIfAbsent(c.layoutKey, k -> new ArrayList<>()).add(c);
+            }
+
+            for (List<IndexedDrawCapture> group : groups.values()) {
+                results.add(buildGroup(group));
+            }
+            // Placeholder fill is deferred until every group's GL work has succeeded.
+            for (GroupResult r : results) r.commit();
+            for (GroupResult r : results) out.add(r.batch);
+            success = true;
+        } finally {
+            if (!success) {
+                for (GroupResult r : results) r.batch.delete();
+            }
+            GLStateManager.glBindVertexArray(prevVAO);
+            GLStateManager.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEBO);
+            GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, prevVBO);
+        }
+
+        return out;
+    }
+
+    private record GroupResult(IndexedDrawBatch batch, List<IndexedDrawCapture> captures,
+                               int[] drawModes, int[] indexCounts, long[] indexOffsets) {
+        void commit() {
+            final int sharedVAO = batch.getSharedVAO();
+            for (int i = 0; i < captures.size(); i++) {
+                captures.get(i).placeholder.fill(sharedVAO, drawModes[i], indexCounts[i], GL11.GL_UNSIGNED_INT, indexOffsets[i]);
+            }
+        }
+    }
+
+    private static GroupResult buildGroup(List<IndexedDrawCapture> group) {
+        long totalVertexBytes = 0;
+        long totalIndexBytes = 0;
+        for (IndexedDrawCapture c : group) {
+            totalVertexBytes += (long) c.vertexCount * c.layoutKey.stride();
+            totalIndexBytes += (long) c.indexCount * 4;   // always GL_UNSIGNED_INT
+        }
+        if (totalVertexBytes > Integer.MAX_VALUE || totalIndexBytes > Integer.MAX_VALUE) {
+            throw new IllegalStateException("batch exceeds 2GiB — split needed");
+        }
+
+        int sharedVAO = 0;
+        int sharedVBO = 0;
+        int sharedEBO = 0;
+        ByteBuffer eboData = null;
+        boolean success = false;
+
+        final int n = group.size();
+        final int[] drawModes = new int[n];
+        final int[] indexCounts = new int[n];
+        final long[] indexOffsets = new long[n];
+
+        try {
+            sharedVAO = GLStateManager.glGenVertexArrays();
+            sharedVBO = GLStateManager.glGenBuffers();
+            sharedEBO = GLStateManager.glGenBuffers();
+            eboData = MemoryUtilities.memAlloc((int) totalIndexBytes);
+
+            GLStateManager.glBindVertexArray(sharedVAO);
+            GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, sharedVBO);
+            GLStateManager.glBufferData(GL15.GL_ARRAY_BUFFER, totalVertexBytes, GL15.GL_STATIC_DRAW);
+
+            int vboBytePos = 0;
+            int eboBytePos = 0;
+            int vertexBase = 0;
+            final long eboAddr = memAddress0(eboData);
+
+            for (int g = 0; g < n; g++) {
+                final IndexedDrawCapture c = group.get(g);
+                final int vBytes = c.vertexCount * c.layoutKey.stride();
+                GLStateManager.glBufferSubData(GL15.GL_ARRAY_BUFFER, vboBytePos, c.vertexData);
+
+                final long srcIdxAddr = memAddress0(c.indexData);
+                final int idxBytes = c.indexCount * 4;
+                if (vertexBase == 0) {
+                    // First capture (or a group that starts at 0) — indices are already
+                    // rebased to [0..vertexCount) in IndexedDrawCapture, so a raw bulk copy
+                    // is correct and strictly faster than the per-index loop.
+                    memCopy(srcIdxAddr, eboAddr + eboBytePos, idxBytes);
+                } else {
+                    final long dstBase = eboAddr + eboBytePos;
+                    for (int i = 0; i < c.indexCount; i++) {
+                        memPutInt(dstBase + i * 4L, memGetInt(srcIdxAddr + i * 4L) + vertexBase);
+                    }
+                }
+
+                drawModes[g] = c.drawMode;
+                indexCounts[g] = c.indexCount;
+                indexOffsets[g] = eboBytePos;
+
+                vboBytePos += vBytes;
+                eboBytePos += idxBytes;
+                vertexBase += c.vertexCount;
+            }
+
+            eboData.position(0).limit((int) totalIndexBytes);
+
+            GLStateManager.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, sharedEBO);
+            GLStateManager.glBufferData(GL15.GL_ELEMENT_ARRAY_BUFFER, eboData, GL15.GL_STATIC_DRAW);
+
+            final AttribLayoutKey layout = group.get(0).layoutKey;
+            final int stride = layout.stride();
+            for (int i = 0; i < layout.locations.length; i++) {
+                final int loc = layout.locations[i];
+                final int size = layout.sizes[i];
+                final int type = layout.types[i];
+                GLStateManager.glVertexAttribPointer(loc, size, type, layout.normalized[i], stride, layout.offset(i));
+                GLStateManager.glEnableVertexAttribArray(loc);
+            }
+
+            success = true;
+            return new GroupResult(new IndexedDrawBatch(sharedVAO, sharedVBO, sharedEBO),
+                group, drawModes, indexCounts, indexOffsets);
+        } finally {
+            if (eboData != null) MemoryUtilities.memFree(eboData);
+            if (!success) {
+                if (sharedVAO != 0) GLStateManager.glDeleteVertexArrays(sharedVAO);
+                if (sharedVBO != 0) GLStateManager.glDeleteBuffers(sharedVBO);
+                if (sharedEBO != 0) GLStateManager.glDeleteBuffers(sharedEBO);
+            }
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/commands/IndexedDrawCapture.java

@@ -0,0 +1,262 @@
+package com.gtnewhorizons.angelica.glsm.recording.commands;
+
+import com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.QuadConverter;
+import com.gtnewhorizons.angelica.glsm.ffp.VAOManager;
+import com.gtnewhorizons.angelica.glsm.recording.AttribSnapshot;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetInt;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetLong;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutInt;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutLong;
+
+
+/** {@link #create} returns null on any recoverable validation failure; callers must not record the placeholder. */
+public final class IndexedDrawCapture {
+    public final AttribLayoutKey layoutKey;
+    public final int drawMode;
+    public final int vertexCount;
+    public final int indexCount;
+    public final ByteBuffer vertexData;
+    public final ByteBuffer indexData;
+    public final BatchedIndexedDrawCmd placeholder;
+    private boolean freed;
+
+    public IndexedDrawCapture(AttribLayoutKey layoutKey, int drawMode, int vertexCount, int indexCount,
+                              ByteBuffer vertexData, ByteBuffer indexData,
+                              BatchedIndexedDrawCmd placeholder) {
+        this.layoutKey = layoutKey;
+        this.drawMode = drawMode;
+        this.vertexCount = vertexCount;
+        this.indexCount = indexCount;
+        this.vertexData = vertexData;
+        this.indexData = indexData;
+        this.placeholder = placeholder;
+    }
+
+    public void freeBuffers() {
+        if (freed) return;
+        freed = true;
+        if (vertexData != null) MemoryUtilities.memFree(vertexData);
+        if (indexData != null) MemoryUtilities.memFree(indexData);
+    }
+
+    public boolean isFreed() {
+        return freed;
+    }
+
+    public static IndexedDrawCapture create(int mode, int indicesCount, int srcIndexType, long indicesOffset, int eboId) {
+        if (indicesCount == 0) return null;
+        if (eboId == 0) {
+            GLStateManager.warnOnce("no-ebo", "[IndexedDrawCapture] glDrawElements in display list with no EBO bound — skipping (mode={} count={} offset={})", mode, indicesCount, indicesOffset);
+            return null;
+        }
+        if (mode == GL11.GL_QUADS && (indicesCount % 4) != 0) {
+            GLStateManager.warnOnce("quads-misaligned", "[IndexedDrawCapture] GL_QUADS with indicesCount={} not a multiple of 4 — skipping", indicesCount);
+            return null;
+        }
+        final int srcIndexSize = VAOManager.Attrib.glTypeSizeBytes(srcIndexType);
+        if (srcIndexSize <= 0) return null;
+
+        final int prevEBO = GLStateManager.getBoundEBO();
+        final int prevVBO = GLStateManager.getBoundVBO();
+        ByteBuffer eboSrc = null;
+        try {
+            GLStateManager.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, eboId);
+            final int eboBufferSize = GLStateManager.glGetBufferParameteri(GL15.GL_ELEMENT_ARRAY_BUFFER, GL15.GL_BUFFER_SIZE);
+            if (eboBufferSize <= 0) {
+                GLStateManager.warnOnce("ebo-size", "[IndexedDrawCapture] GL_BUFFER_SIZE={} for EBO {}", eboBufferSize, eboId);
+                return null;
+            }
+            final long eboReadSize = (long) indicesCount * srcIndexSize;
+            if (indicesOffset < 0 || indicesOffset + eboReadSize > eboBufferSize) {
+                GLStateManager.warnOnce("ebo-range", "[IndexedDrawCapture] EBO range {}+{} exceeds buffer size {} — skipping", indicesOffset, eboReadSize, eboBufferSize);
+                return null;
+            }
+            eboSrc = MemoryUtilities.memAlloc((int) eboReadSize);
+            GLStateManager.glGetBufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, indicesOffset, eboSrc);
+            return bake(mode, indicesCount, srcIndexType, MemoryUtilities.memAddress0(eboSrc));
+        } finally {
+            if (eboSrc != null) MemoryUtilities.memFree(eboSrc);
+            GLStateManager.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEBO);
+            GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, prevVBO);
+        }
+    }
+
+    public static IndexedDrawCapture createFromClientIndices(int mode, int indicesCount, int srcIndexType, long indexSrcAddr, long srcByteLength) {
+        if (indicesCount == 0) return null;
+        if (indexSrcAddr == 0L) return null;
+        if (mode == GL11.GL_QUADS && (indicesCount % 4) != 0) {
+            GLStateManager.warnOnce("quads-misaligned", "[IndexedDrawCapture] GL_QUADS with indicesCount={} not a multiple of 4 - skipping", indicesCount);
+            return null;
+        }
+        final int idxSize = VAOManager.Attrib.glTypeSizeBytes(srcIndexType);
+        if (idxSize <= 0) return null;
+        if ((long) indicesCount * idxSize > srcByteLength) {
+            GLStateManager.warnOnce("client-idx-range", "[IndexedDrawCapture] index count {} ({} bytes) exceeds client buffer {} bytes - skipping", indicesCount, (long) indicesCount * idxSize, srcByteLength);
+            return null;
+        }
+        return bake(mode, indicesCount, srcIndexType, indexSrcAddr);
+    }
+
+    private static IndexedDrawCapture bake(int mode, int indicesCount, int srcIndexType, long indexSrcAddr) {
+        AttribSnapshot snap = null;
+        ByteBuffer vertexData = null;
+        ByteBuffer indexData = null;
+        boolean success = false;
+        try {
+            final long minMax = QuadConverter.scanMinMaxIndex(indexSrcAddr, srcIndexType, indicesCount);
+            if (minMax == -1L) {
+                GLStateManager.warnOnce("min-max", "[IndexedDrawCapture] failed to determine min/max vertex for indexType={}", srcIndexType);
+                return null;
+            }
+            final int minVtx = (int) (minMax & 0xFFFFFFFFL);
+            final int maxVtx = (int) (minMax >>> 32);
+            final int vertexCount = maxVtx - minVtx + 1;
+
+            snap = AttribSnapshot.snapshot(minVtx, vertexCount);
+
+            int enabledCount = 0;
+            for (int i = 0; i < VAOManager.MAX_ATTRIBS; i++) {
+                if (snap.get(i) != null) enabledCount++;
+            }
+            if (enabledCount == 0) {
+                GLStateManager.warnOnce("no-attribs", "[IndexedDrawCapture] no enabled attributes — skipping");
+                return null;
+            }
+            final int[] locations = new int[enabledCount];
+            final int[] sizes = new int[enabledCount];
+            final int[] types = new int[enabledCount];
+            final boolean[] normalized = new boolean[enabledCount];
+            int k = 0;
+            for (int i = 0; i < VAOManager.MAX_ATTRIBS; i++) {
+                final AttribSnapshot.AttribDesc d = snap.get(i);
+                if (d == null) continue;
+                locations[k] = i;
+                sizes[k] = d.size();
+                types[k] = d.type();
+                normalized[k] = d.normalized();
+                k++;
+            }
+            final AttribLayoutKey layoutKey = new AttribLayoutKey(locations, sizes, types, normalized);
+            final int tightStride = layoutKey.stride();
+
+            ByteBuffer sharedSrcBuffer = null;
+            long sharedSrcBase = 0;
+            int sharedSrcStride = -1;
+            boolean tightSrc = true;
+            for (int a = 0; a < enabledCount; a++) {
+                final AttribSnapshot.AttribDesc d = snap.get(locations[a]);
+                final int relOffset = (int) (d.offset() - d.readBufferBaseOffset());
+
+                final long readStart = relOffset + (long) minVtx * d.effectiveStride();
+                final long readEnd = relOffset + (long) maxVtx * d.effectiveStride() + (long) d.size() * d.typeSizeBytes();
+                if (readStart < 0 || readEnd > d.readBuffer().capacity()) {
+                    GLStateManager.warnOnce("vtx-oob", "[IndexedDrawCapture] attrib {} read extent {} exceeds snapshot {} bytes - skipping", d.location(), readEnd, d.readBuffer().capacity());
+                    return null;
+                }
+                if (a == 0) {
+                    sharedSrcBuffer = d.readBuffer();
+                    sharedSrcStride = d.effectiveStride();
+                    sharedSrcBase = MemoryUtilities.memAddress0(sharedSrcBuffer) + relOffset + (long) minVtx * sharedSrcStride;
+                    if (relOffset != layoutKey.offset(0)) tightSrc = false;
+                } else if (d.readBuffer() != sharedSrcBuffer || d.effectiveStride() != sharedSrcStride || relOffset != layoutKey.offset(a)) {
+                    tightSrc = false;
+                }
+            }
+            if (tightSrc && sharedSrcStride != tightStride) tightSrc = false;
+
+            vertexData = MemoryUtilities.memAlloc(vertexCount * tightStride);
+            final long dstAddr = MemoryUtilities.memAddress0(vertexData);
+            if (tightSrc) {
+                MemoryUtilities.memCopy(sharedSrcBase, dstAddr, (long) vertexCount * tightStride);
+            } else {
+                for (int a = 0; a < enabledCount; a++) {
+                    final AttribSnapshot.AttribDesc d = snap.get(locations[a]);
+                    final int attribBytes = d.size() * d.typeSizeBytes();
+                    final int srcStride = d.effectiveStride();
+                    final long srcStart = MemoryUtilities.memAddress0(d.readBuffer()) + (d.offset() - d.readBufferBaseOffset()) + (long) minVtx * srcStride;
+                    final long dstStart = dstAddr + layoutKey.offset(a);
+                    copyStrided(srcStart, srcStride, dstStart, tightStride, attribBytes, vertexCount);
+                }
+            }
+
+            final int bakedDrawMode;
+            final int bakedIndexCount;
+            if (mode == GL11.GL_QUADS) {
+                final int quadCount = indicesCount / 4;
+                bakedIndexCount = quadCount * 6;
+                indexData = MemoryUtilities.memAlloc(bakedIndexCount * 4);
+                QuadConverter.triangulateQuads(indexSrcAddr, srcIndexType, MemoryUtilities.memAddress0(indexData), GL11.GL_UNSIGNED_INT, quadCount, minVtx);
+                bakedDrawMode = GL11.GL_TRIANGLES;
+            } else {
+                bakedIndexCount = indicesCount;
+                indexData = MemoryUtilities.memAlloc(bakedIndexCount * 4);
+                QuadConverter.widenIndices(indexSrcAddr, srcIndexType, MemoryUtilities.memAddress0(indexData), GL11.GL_UNSIGNED_INT, indicesCount, minVtx);
+                bakedDrawMode = mode;
+            }
+
+            final BatchedIndexedDrawCmd placeholder = new BatchedIndexedDrawCmd();
+
+            final IndexedDrawCapture out = new IndexedDrawCapture(layoutKey, bakedDrawMode, vertexCount, bakedIndexCount, vertexData, indexData, placeholder);
+            success = true;
+            return out;
+        } finally {
+            if (snap != null) snap.free();
+            if (!success) {
+                if (vertexData != null) MemoryUtilities.memFree(vertexData);
+                if (indexData != null) MemoryUtilities.memFree(indexData);
+            }
+        }
+    }
+
+    /**
+     * Copy {@code attribBytes} per vertex from {@code src} (stride {@code srcStride}) to
+     * {@code dst} (stride {@code dstStride}) for {@code vertexCount} vertices.
+     *
+     * <p>Specializes on the common attribute sizes (4 / 8 / 12 / 16) so the hot path is
+     * one or two {@code memPut} calls per vertex instead of a JNI-ish {@code memCopy}
+     * dispatch. Falls through to {@code memCopy} for exotic sizes.
+     */
+    private static void copyStrided(long src, int srcStride, long dst, int dstStride, int attribBytes, int vertexCount) {
+        switch (attribBytes) {
+            case 4 -> {
+                for (int v = 0; v < vertexCount; v++) {
+                    memPutInt(dst, memGetInt(src));
+                    src += srcStride; dst += dstStride;
+                }
+            }
+            case 8 -> {
+                for (int v = 0; v < vertexCount; v++) {
+                    memPutLong(dst, memGetLong(src));
+                    src += srcStride; dst += dstStride;
+                }
+            }
+            case 12 -> {
+                for (int v = 0; v < vertexCount; v++) {
+                    memPutLong(dst, memGetLong(src));
+                    memPutInt(dst + 8, memGetInt(src + 8));
+                    src += srcStride; dst += dstStride;
+                }
+            }
+            case 16 -> {
+                for (int v = 0; v < vertexCount; v++) {
+                    memPutLong(dst, memGetLong(src));
+                    memPutLong(dst + 8, memGetLong(src + 8));
+                    src += srcStride; dst += dstStride;
+                }
+            }
+            default -> {
+                for (int v = 0; v < vertexCount; v++) {
+                    MemoryUtilities.memCopy(src, dst, attribBytes);
+                    src += srcStride; dst += dstStride;
+                }
+            }
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/commands/MultMatrixCmd.java

@@ -0,0 +1,36 @@
+package com.gtnewhorizons.angelica.glsm.recording.commands;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.jetbrains.annotations.NotNull;
+import org.joml.Matrix4f;
+import org.lwjgl.BufferUtils;
+
+import java.nio.FloatBuffer;
+
+/**
+ * Command: glMultMatrix(matrix)
+ * Multiplies the current matrix by the specified matrix.
+ */
+public record MultMatrixCmd(Matrix4f matrix, FloatBuffer buffer) implements DisplayListCommand {
+
+    /**
+     * Create a MultMatrixCmd with pre-allocated buffer.
+     */
+    public static MultMatrixCmd create(Matrix4f matrix) {
+        final FloatBuffer buffer = BufferUtils.createFloatBuffer(16);
+        matrix.get(buffer);
+        buffer.rewind();
+        return new MultMatrixCmd(new Matrix4f(matrix), buffer);
+    }
+
+    @Override
+    public void execute() {
+        buffer.rewind();
+        GLStateManager.glMultMatrix(buffer);
+    }
+
+    @Override
+    public @NotNull String toString() {
+        return String.format("MultMatrix(%s)", matrix);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/commands/PixelDataSnapshot.java

@@ -0,0 +1,52 @@
+package com.gtnewhorizons.angelica.glsm.recording.commands;
+
+import org.jetbrains.annotations.Nullable;
+
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.nio.DoubleBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAlloc;
+
+final class PixelDataSnapshot {
+    private PixelDataSnapshot() {}
+
+    static @Nullable ByteBuffer copy(@Nullable ByteBuffer pixels) {
+        if (pixels == null) return null;
+        final int pos = pixels.position();
+        final ByteBuffer out = memAlloc(pixels.remaining()).order(ByteOrder.nativeOrder());
+        out.put(pixels);
+        out.flip();
+        pixels.position(pos);
+        return out;
+    }
+
+    static @Nullable ByteBuffer copy(@Nullable IntBuffer pixels) {
+        if (pixels == null) return null;
+        final int pos = pixels.position();
+        final ByteBuffer out = memAlloc(pixels.remaining() * 4).order(ByteOrder.nativeOrder());
+        out.asIntBuffer().put(pixels);
+        pixels.position(pos);
+        return out;
+    }
+
+    static @Nullable ByteBuffer copy(@Nullable FloatBuffer pixels) {
+        if (pixels == null) return null;
+        final int pos = pixels.position();
+        final ByteBuffer out = memAlloc(pixels.remaining() * 4).order(ByteOrder.nativeOrder());
+        out.asFloatBuffer().put(pixels);
+        pixels.position(pos);
+        return out;
+    }
+
+    static @Nullable ByteBuffer copy(@Nullable DoubleBuffer pixels) {
+        if (pixels == null) return null;
+        final int pos = pixels.position();
+        final ByteBuffer out = memAlloc(pixels.remaining() * 8).order(ByteOrder.nativeOrder());
+        out.asDoubleBuffer().put(pixels);
+        pixels.position(pos);
+        return out;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/commands/TexImage2DCmd.java

@@ -0,0 +1,83 @@
+package com.gtnewhorizons.angelica.glsm.recording.commands;
+
+import com.gtnewhorizons.angelica.glsm.GLDebug;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.states.PixelUnpackState;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.nio.ByteBuffer;
+import java.nio.DoubleBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memFree;
+
+/**
+ * Command: glTexImage2D(target, level, internalformat, width, height, border, format, type, pixels)
+ * Specifies a two-dimensional texture image during display list playback.
+ */
+public record TexImage2DCmd(
+    int target,
+    int level,
+    int internalformat,
+    int width,
+    int height,
+    int border,
+    int format,
+    int type,
+    @Nullable ByteBuffer pixels,
+    @Nullable PixelUnpackState unpack
+) implements DisplayListCommand {
+
+    public TexImage2DCmd {
+        if (pixels == null) {
+            unpack = null;
+        }
+    }
+
+    public static TexImage2DCmd fromIntBuffer(int target, int level, int internalformat, int width, int height, int border, int format, int type, @Nullable IntBuffer pixels, PixelUnpackState unpack) {
+        return new TexImage2DCmd(target, level, internalformat, width, height, border, format, type, PixelDataSnapshot.copy(pixels), unpack);
+    }
+
+    public static TexImage2DCmd fromFloatBuffer(int target, int level, int internalformat, int width, int height, int border, int format, int type, @Nullable FloatBuffer pixels, PixelUnpackState unpack) {
+        return new TexImage2DCmd(target, level, internalformat, width, height, border, format, type, PixelDataSnapshot.copy(pixels), unpack);
+    }
+
+    public static TexImage2DCmd fromDoubleBuffer(int target, int level, int internalformat, int width, int height, int border, int format, int type, @Nullable DoubleBuffer pixels, PixelUnpackState unpack) {
+        return new TexImage2DCmd(target, level, internalformat, width, height, border, format, type, PixelDataSnapshot.copy(pixels), unpack);
+    }
+
+    public static TexImage2DCmd fromByteBuffer(int target, int level, int internalformat, int width, int height, int border, int format, int type, @Nullable ByteBuffer pixels, PixelUnpackState unpack) {
+        return new TexImage2DCmd(target, level, internalformat, width, height, border, format, type, PixelDataSnapshot.copy(pixels), unpack);
+    }
+
+    @Override
+    public void execute() {
+        if (pixels == null) {
+            GLStateManager.glTexImage2D(target, level, internalformat, width, height, border, format, type, (ByteBuffer) null);
+            return;
+        }
+        GLStateManager.forcePixelUnpackState(unpack);
+        try {
+            GLStateManager.glTexImage2D(target, level, internalformat, width, height, border, format, type, pixels);
+        } finally {
+            GLStateManager.restorePixelUnpackState(unpack);
+        }
+    }
+
+    @Override
+    public void delete() {
+        if (pixels != null) {
+            memFree(pixels);
+        }
+    }
+
+    @Override
+    public @NotNull String toString() {
+        String dataStr = pixels != null ? (pixels.remaining() + " bytes") : "null";
+        return String.format("TexImage2D(target=%s, level=%d, internalformat=%s, %dx%d, border=%d, format=%s, type=%s, data=%s, unpack=%s)",
+            GLDebug.getTextureTargetName(target), level, GLDebug.getTextureFormatName(internalformat),
+            width, height, border, GLDebug.getTextureFormatName(format), GLDebug.getDataTypeName(type), dataStr, unpack);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/recording/commands/TexSubImage2DCmd.java

@@ -0,0 +1,83 @@
+package com.gtnewhorizons.angelica.glsm.recording.commands;
+
+import com.gtnewhorizons.angelica.glsm.GLDebug;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.states.PixelUnpackState;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.nio.ByteBuffer;
+import java.nio.DoubleBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memFree;
+
+/**
+ * Command: glTexSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels)
+ * Updates a portion of an existing two-dimensional texture image during display list playback.
+ */
+public record TexSubImage2DCmd(
+    int target,
+    int level,
+    int xoffset,
+    int yoffset,
+    int width,
+    int height,
+    int format,
+    int type,
+    @Nullable ByteBuffer pixels,
+    @Nullable PixelUnpackState unpack
+) implements DisplayListCommand {
+
+    public TexSubImage2DCmd {
+        if (pixels == null) {
+            unpack = null;
+        }
+    }
+
+    public static TexSubImage2DCmd fromIntBuffer(int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, @Nullable IntBuffer pixels, PixelUnpackState unpack) {
+        return new TexSubImage2DCmd(target, level, xoffset, yoffset, width, height, format, type, PixelDataSnapshot.copy(pixels), unpack);
+    }
+
+    public static TexSubImage2DCmd fromFloatBuffer(int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, @Nullable FloatBuffer pixels, PixelUnpackState unpack) {
+        return new TexSubImage2DCmd(target, level, xoffset, yoffset, width, height, format, type, PixelDataSnapshot.copy(pixels), unpack);
+    }
+
+    public static TexSubImage2DCmd fromDoubleBuffer(int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, @Nullable DoubleBuffer pixels, PixelUnpackState unpack) {
+        return new TexSubImage2DCmd(target, level, xoffset, yoffset, width, height, format, type, PixelDataSnapshot.copy(pixels), unpack);
+    }
+
+    public static TexSubImage2DCmd fromByteBuffer(int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, @Nullable ByteBuffer pixels, PixelUnpackState unpack) {
+        return new TexSubImage2DCmd(target, level, xoffset, yoffset, width, height, format, type, PixelDataSnapshot.copy(pixels), unpack);
+    }
+
+    @Override
+    public void execute() {
+        if (pixels == null) {
+            GLStateManager.glTexSubImage2D(target, level, xoffset, yoffset, width, height, format, type, (ByteBuffer) null);
+            return;
+        }
+        GLStateManager.forcePixelUnpackState(unpack);
+        try {
+            GLStateManager.glTexSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);
+        } finally {
+            GLStateManager.restorePixelUnpackState(unpack);
+        }
+    }
+
+    @Override
+    public void delete() {
+        if (pixels != null) {
+            memFree(pixels);
+        }
+    }
+
+    @Override
+    public @NotNull String toString() {
+        String dataStr = pixels != null ? (pixels.remaining() + " bytes") : "null";
+        return String.format("TexSubImage2D(target=%s, level=%d, offset=(%d,%d), %dx%d, format=%s, type=%s, data=%s, unpack=%s)",
+            GLDebug.getTextureTargetName(target), level, xoffset, yoffset, width, height,
+            GLDebug.getTextureFormatName(format), GLDebug.getDataTypeName(type), dataStr, unpack);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/redirect/GLSMRedirector.java

@@ -0,0 +1,712 @@
+package com.gtnewhorizons.angelica.glsm.redirect;
+
+import com.google.common.collect.ImmutableSet;
+import com.gtnewhorizon.gtnhlib.asm.ClassConstantPoolParser;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.objectweb.asm.Handle;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.AbstractInsnNode;
+import org.objectweb.asm.tree.ClassNode;
+import org.objectweb.asm.tree.IntInsnNode;
+import org.objectweb.asm.tree.InvokeDynamicInsnNode;
+import org.objectweb.asm.tree.LdcInsnNode;
+import org.objectweb.asm.tree.MethodInsnNode;
+import org.objectweb.asm.tree.MethodNode;
+import org.objectweb.asm.tree.TypeInsnNode;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Core GL call redirector for GLSM. Rewrites bytecode so that GL calls go through {@code GLStateManager} for state tracking and backend abstraction.
+ * <p>
+ * THIS CLASS MIGHT BE LOADED ON A DIFFERENT CLASS LOADER.
+ * IT SHOULD NOT CALL ANY CODE FROM THE MAIN MOD.
+ */
+public class GLSMRedirector {
+
+    private static final boolean ASSERT_MAIN_THREAD = Boolean.getBoolean("angelica.assertMainThread");
+    private static final boolean LOG_SPAM = Boolean.getBoolean("angelica.redirectorLogspam");
+    private static final Logger LOGGER = LogManager.getLogger("GLSMRedirector");
+
+    private static final String Drawable = "org/lwjgl/opengl/Drawable";
+    private static final String GLStateManager = "com/gtnewhorizons/angelica/glsm/GLStateManager";
+    private static final String GL_PREFIX = "org/lwjgl/opengl/GL";
+    private static final String ARBVertexArrayObject = "org/lwjgl/opengl/ARBVertexArrayObject";
+    private static final String APPLEVertexArrayObject = "org/lwjgl/opengl/APPLEVertexArrayObject";
+    private static final String Project = "org/lwjgl/util/glu/Project";
+    private static final String GLU = "org/lwjgl/util/glu/GLU";
+    private static final String OpenGlHelper = "net/minecraft/client/renderer/OpenGlHelper";
+    private static final String EXTBlendFunc = "org/lwjgl/opengl/EXTBlendFuncSeparate";
+    private static final String ARBMultiTexture = "org/lwjgl/opengl/ARBMultitexture";
+    private static final String ARBShaderObjects = "org/lwjgl/opengl/ARBShaderObjects";
+    private static final String ARBInstancedArrays = "org/lwjgl/opengl/ARBInstancedArrays";
+    private static final String ARBDrawInstanced = "org/lwjgl/opengl/ARBDrawInstanced";
+    private static final String EXTDrawInstanced = "org/lwjgl/opengl/EXTDrawInstanced";
+    private static final String ARBBufferObject = "org/lwjgl/opengl/ARBBufferObject";
+    private static final String ARBVertexBufferObject = "org/lwjgl/opengl/ARBVertexBufferObject";
+    private static final String ARBBufferStorage = "org/lwjgl/opengl/ARBBufferStorage";
+    private static final String ARBCopyBuffer = "org/lwjgl/opengl/ARBCopyBuffer";
+    private static final String ARBMapBufferRange = "org/lwjgl/opengl/ARBMapBufferRange";
+
+    // Redirect VAO related calls from NHLib
+    private static final String UniversalVAO = "com/gtnewhorizon/gtnhlib/client/opengl/UniversalVAO";
+
+    private static final String MinecraftClient = "net.minecraft.client";
+    private static final String SplashProgress = "cpw.mods.fml.client.SplashProgress";
+    private static final Set<String> ExcludedMinecraftMainThreadChecks = ImmutableSet.of(
+        "startGame", "func_71384_a",
+        "initializeTextures", "func_77474_a"
+    );
+
+    private static final Map<String, Map<String, String>> methodRedirects = new HashMap<>(32);
+    private static final Map<String, String> glMethodRedirects = new HashMap<>(256);
+    private static final Map<Integer, String> glCapRedirects = new HashMap<>();
+    private static final Map<String, String> typeRedirects = new HashMap<>();
+    private static final ClassConstantPoolParser cstPoolParser;
+
+    private static final String[] CORE_EXCLUSIONS = {
+        "org.lwjgl",
+        "com.gtnewhorizon.gtnhlib.asm",
+        "com.gtnewhorizons.angelica.glsm.",
+        "me.eigenraven.lwjgl3ify"
+    };
+
+    static {
+        glCapRedirects.put(org.lwjgl.opengl.GL11.GL_ALPHA_TEST, "AlphaTest");
+        glCapRedirects.put(org.lwjgl.opengl.GL11.GL_BLEND, "Blend");
+        glCapRedirects.put(org.lwjgl.opengl.GL11.GL_DEPTH_TEST, "DepthTest");
+        glCapRedirects.put(org.lwjgl.opengl.GL11.GL_CULL_FACE, "Cull");
+        glCapRedirects.put(org.lwjgl.opengl.GL11.GL_LIGHTING, "Lighting");
+        glCapRedirects.put(org.lwjgl.opengl.GL11.GL_TEXTURE_2D, "Texture");
+        glCapRedirects.put(org.lwjgl.opengl.GL11.GL_FOG, "Fog");
+        glCapRedirects.put(org.lwjgl.opengl.GL12.GL_RESCALE_NORMAL, "RescaleNormal");
+        glCapRedirects.put(org.lwjgl.opengl.GL11.GL_SCISSOR_TEST, "ScissorTest");
+
+        final var gl11 = RedirectMap.newMap()
+            // glEnable/Disable - Special cased in GLSMRedirector, but included here for the external API
+            .add("glEnable")
+            .add("glDisable")
+            .add("glAlphaFunc")
+            .add("glBegin")
+            .add("glBindTexture")
+            .add("glBlendFunc")
+            .add("glCallList")
+            .add("glCallLists")
+            .add("glClear")
+            .add("glClearColor")
+            .add("glClearDepth")
+            .add("glClearStencil")
+            .add("glClipPlane")
+            .add("glColor3b")
+            .add("glColor3d")
+            .add("glColor3f")
+            .add("glColor3ub")
+            .add("glColor4b")
+            .add("glColor4d")
+            .add("glColor4f")
+            .add("glColor4ub")
+            .add("glColorMask")
+            .add("glColorMaterial")
+            .add("glDeleteLists")
+            .add("glGenLists")
+            .add("glGenTextures")
+            .add("glIsList")
+            .add("glDeleteTextures")
+            .add("glDepthFunc")
+            .add("glDepthMask")
+            .add("glDepthRange")
+            .add("glDrawArrays")
+            .add("glDrawBuffer")
+            .add("glDrawElements")
+            .add("glEdgeFlag")
+            .add("glEnd")
+            .add("glEndList")
+            .add("glFog")
+            .add("glFogf")
+            .add("glFogi")
+            .add("glFrustum")
+            .add("glGetBoolean")
+            .add("glGetFloat")
+            .add("glGetFloatv", "glGetFloat")
+            .add("glGetInteger")
+            .add("glGetLight")
+            .add("glGetMaterial")
+            .add("glGetTexLevelParameteri")
+            .add("glGetTexParameterf")
+            .add("glGetTexParameteri")
+            .add("glIsEnabled")
+            .add("glMaterial")
+            .add("glMaterialf")
+            .add("glMateriali")
+            .add("glLight")
+            .add("glLightf")
+            .add("glLighti")
+            .add("glLightModel")
+            .add("glLightModelf")
+            .add("glLightModeli")
+            .add("glLineStipple")
+            .add("glLineWidth")
+            .add("glListBase")
+            .add("glLoadIdentity")
+            .add("glLoadMatrix")
+            .add("glLogicOp")
+            .add("glMatrixMode")
+            .add("glMultMatrix")
+            .add("glNewList")
+            .add("glNormal3b")
+            .add("glNormal3d")
+            .add("glFlush")
+            .add("glFinish")
+            .add("glGetError")
+            .add("glGetString")
+            .add("glGetTexImage")
+            .add("glNormal3f")
+            .add("glNormal3i")
+            .add("glOrtho")
+            .add("glPopAttrib")
+            .add("glPopMatrix")
+            .add("glPushAttrib")
+            .add("glPushMatrix")
+            .add("glRasterPos2d")
+            .add("glRasterPos2f")
+            .add("glRasterPos2i")
+            .add("glRasterPos3d")
+            .add("glRasterPos3f")
+            .add("glRasterPos3i")
+            .add("glRasterPos4d")
+            .add("glRasterPos4f")
+            .add("glRasterPos4i")
+            .add("glRotated")
+            .add("glRotatef")
+            .add("glScaled")
+            .add("glScalef")
+            .add("glShadeModel")
+            .add("glTexCoord1d")
+            .add("glTexCoord1f")
+            .add("glTexCoord2d")
+            .add("glTexCoord2f")
+            .add("glTexCoord3d")
+            .add("glTexCoord3f")
+            .add("glTexCoord4d")
+            .add("glTexCoord4f")
+            .add("glTexEnvi")
+            .add("glTexEnvf")
+            .add("glTexEnv")
+            .add("glGetTexEnv")
+            .add("glGetTexEnvi")
+            .add("glGetTexEnvf")
+            .add("glTexGeni")
+            .add("glTexGenf")
+            .add("glTexGend")
+            .add("glTexGen")
+            .add("glGetTexGen")
+            .add("glGetTexGeni")
+            .add("glGetTexGenf")
+            .add("glGetTexGend")
+            .add("glTexImage1D")
+            .add("glTexImage2D")
+            .add("glTexImage3D")
+            .add("glTexSubImage1D")
+            .add("glTexSubImage2D")
+            .add("glCopyTexImage1D")
+            .add("glCopyTexImage2D")
+            .add("glCopyTexSubImage1D")
+            .add("glCopyTexSubImage2D")
+            .add("glPixelStoref")
+            .add("glPixelStorei")
+            .add("glPixelTransferf")
+            .add("glPixelTransferi")
+            .add("glTexParameter")
+            .add("glTexParameterf")
+            .add("glTexParameteri")
+            .add("glCullFace")
+            .add("glFrontFace")
+            .add("glHint")
+            .add("glLineStipple")
+            .add("glLineWidth")
+            .add("glPointSize")
+            .add("glPolygonMode")
+            .add("glPolygonOffset")
+            .add("glPolygonStipple")
+            .add("glAccum")
+            .add("glReadBuffer")
+            .add("glSampleCoverage")
+            .add("glScissor")
+            .add("glStencilFunc")
+            .add("glStencilFuncSeparate")
+            .add("glStencilMask")
+            .add("glStencilMaskSeparate")
+            .add("glStencilOp")
+            .add("glStencilOpSeparate")
+            .add("glTranslated")
+            .add("glTranslatef")
+            .add("glVertex2d")
+            .add("glVertex2f")
+            .add("glVertex2i")
+            .add("glVertex3d")
+            .add("glVertex3f")
+            .add("glVertex3i")
+            .add("glVertexPointer")
+            .add("glColorPointer")
+            .add("glNormalPointer")
+            .add("glTexCoordPointer")
+            .add("glEnableClientState")
+            .add("glDisableClientState")
+            .add("glInterleavedArrays")
+            .add("glPushClientAttrib")
+            .add("glPopClientAttrib")
+            .add("glViewport")
+            .add("glFeedbackBuffer")
+            .add("glRenderMode")
+            .add("glPassThrough")
+            .add("glSelectBuffer")
+            .add("glInitNames")
+            .add("glPushName")
+            .add("glPopName")
+            .add("glLoadName");
+        final var gl12 = RedirectMap.newMap()
+            .add("glTexImage3D")
+            .add("glTexSubImage3D")
+            .add("glCopyTexSubImage3D");
+        final var gl13 = RedirectMap.newMap()
+            .add("glActiveTexture")
+            .add("glSampleCoverage")
+            .add("glClientActiveTexture")
+            .add("glMultiTexCoord2f")
+            .add("glMultiTexCoord2d")
+            .add("glMultiTexCoord2s");
+        final var gl14 = RedirectMap.newMap()
+            .add("glBlendFuncSeparate", "tryBlendFuncSeparate")
+            .add("glBlendColor")
+            .add("glBlendEquation");
+        final var gl15 = RedirectMap.newMap()
+            .add("glGenBuffers")
+            .add("glBindBuffer")
+            .add("glDeleteBuffers")
+            .add("glBufferData")
+            .add("nglBufferData")
+            .add("glBufferSubData")
+            .add("nglBufferSubData")
+            .add("glMapBuffer")
+            .add("glUnmapBuffer")
+            .add("glGetBufferSubData")
+            .add("nglGetBufferSubData")
+            .add("glGetBufferParameteri")
+            .add("glGetBufferParameter")
+            .add("glGetBufferParameteriv")
+            .add("glIsBuffer");
+        final var gl20 = RedirectMap.newMap()
+            .add("glBlendEquationSeparate")
+            .add("glDrawBuffers")
+            .add("glStencilFuncSeparate")
+            .add("glStencilMaskSeparate")
+            .add("glStencilOpSeparate")
+            .add("glUseProgram")
+            .add("glShaderSource")
+            .add("nglShaderSource")
+            .add("glLinkProgram")
+            .add("glDeleteProgram")
+            .add("glCreateShader")
+            .add("glCompileShader")
+            .add("glCreateProgram")
+            .add("glAttachShader")
+            .add("glDetachShader")
+            .add("glValidateProgram")
+            .add("glGetUniformLocation")
+            .add("glGetAttribLocation")
+            .add("glUniform1f")
+            .add("glUniform2f")
+            .add("glUniform3f")
+            .add("glUniform4f")
+            .add("glUniform1i")
+            .add("glUniform2i")
+            .add("glUniform3i")
+            .add("glUniform4i")
+            .add("glUniform1")
+            .add("glUniform2")
+            .add("glUniform3")
+            .add("glUniform4")
+            .add("glUniformMatrix2")
+            .add("glUniformMatrix3")
+            .add("glUniformMatrix4")
+            .add("glUniformMatrix4fv", "glUniformMatrix4")
+            .add("glDeleteShader")
+            .add("glGetShaderi")
+            .add("glGetShaderInfoLog")
+            .add("glGetProgrami")
+            .add("glGetProgramInfoLog")
+            .add("glBindAttribLocation")
+            .add("glVertexAttrib2f")
+            .add("glVertexAttrib2s")
+            .add("glVertexAttrib3f")
+            .add("glVertexAttrib4f")
+            .add("glGetActiveUniform")
+            .add("glGetAttachedShaders")
+            .add("glGetShaderSource")
+            .add("glGetUniform")
+            .add("glVertexAttribPointer")
+            .add("glEnableVertexAttribArray")
+            .add("glDisableVertexAttribArray");
+        final var gl30 = RedirectMap.newMap()
+            .add("glGenVertexArrays")
+            .add("glBindVertexArray")
+            .add("glDeleteVertexArrays")
+            .add("glIsVertexArray")
+            .add("glBindFramebuffer")
+            .add("glDeleteFramebuffers")
+            .add("glGenFramebuffers")
+            .add("glCheckFramebufferStatus")
+            .add("glFramebufferTexture2D")
+            .add("glVertexAttribIPointer")
+            .add("glGenerateMipmap")
+            .add("glGetFramebufferAttachmentParameteri")
+            .add("glBlitFramebuffer")
+            .add("glMapBufferRange")
+            .add("glFlushMappedBufferRange");
+        final var gl31 = RedirectMap.newMap()
+            .add("glDrawElementsInstanced")
+            .add("glDrawArraysInstanced")
+            .add("glCopyBufferSubData");
+        final var gl32 = RedirectMap.newMap()
+            .add("glFramebufferTexture");
+        final var gl33 = RedirectMap.newMap()
+            .add("glGenSamplers")
+            .add("glDeleteSamplers")
+            .add("glBindSampler")
+            .add("glSamplerParameteri")
+            .add("glSamplerParameterf")
+            .add("glVertexAttribDivisor");
+        final var gl42 = RedirectMap.newMap()
+            .add("glBindImageTexture")
+            .add("glMemoryBarrier")
+            .add("glTexStorage2D");
+        final var gl43 = RedirectMap.newMap()
+            .add("glDispatchCompute")
+            .add("glClearBufferSubData")
+            .add("glBindVertexBuffer")
+            .add("glVertexAttribFormat")
+            .add("glVertexAttribIFormat")
+            .add("glVertexAttribBinding");
+        final var gl44 = RedirectMap.newMap()
+            .add("glBufferStorage")
+            .add("glClearTexImage");
+        final var gl45 = RedirectMap.newMap()
+            .add("glCreateBuffers")
+            .add("glNamedBufferData")
+            .add("glNamedBufferSubData");
+
+        // Merge all GL version maps into the flat lookup
+        glMethodRedirects.putAll(gl11);
+        glMethodRedirects.putAll(gl12);
+        glMethodRedirects.putAll(gl13);
+        glMethodRedirects.putAll(gl14);
+        glMethodRedirects.putAll(gl15);
+        glMethodRedirects.putAll(gl20);
+        glMethodRedirects.putAll(gl30);
+        glMethodRedirects.putAll(gl31);
+        glMethodRedirects.putAll(gl32);
+        glMethodRedirects.putAll(gl33);
+        glMethodRedirects.putAll(gl42);
+        glMethodRedirects.putAll(gl43);
+        glMethodRedirects.putAll(gl44);
+        glMethodRedirects.putAll(gl45);
+
+        // MINECRAFT
+        methodRedirects.put(OpenGlHelper, RedirectMap.newMap()
+            .add("glBlendFunc", "tryBlendFuncSeparate")
+            .add("func_148821_a", "tryBlendFuncSeparate")
+            .add("func_153171_g", "glBindFramebuffer")
+            .add("func_153174_h", "glDeleteFramebuffers")
+            .add("func_153165_e", "glGenFramebuffers")
+            .add("func_153167_i", "glCheckFramebufferStatus")
+            .add("func_153188_a", "glFramebufferTexture2D")
+            .add("setActiveTexture")
+            .add("setLightmapTextureCoords")
+            .add("isFramebufferEnabled")
+        );
+        methodRedirects.put(EXTBlendFunc, RedirectMap.newMap().add("glBlendFuncSeparateEXT", "tryBlendFuncSeparate"));
+
+        // ARB
+        methodRedirects.put(ARBMultiTexture, RedirectMap.newMap()
+            .add("glActiveTextureARB")
+        );
+        methodRedirects.put(ARBShaderObjects, RedirectMap.newMap()
+            .add("glUseProgramObjectARB", "glUseProgram")
+            .add("glShaderSourceARB", "glShaderSource")
+            .add("glLinkProgramARB", "glLinkProgram")
+            .add("glCreateShaderObjectARB", "glCreateShader")
+            .add("glCompileShaderARB", "glCompileShader")
+            .add("glCreateProgramObjectARB", "glCreateProgram")
+            .add("glAttachObjectARB", "glAttachShader")
+            .add("glDetachObjectARB", "glDetachShader")
+            .add("glValidateProgramARB", "glValidateProgram")
+            .add("glGetUniformLocationARB", "glGetUniformLocation")
+            .add("glGetAttribLocationARB", "glGetAttribLocation")
+            .add("glDeleteObjectARB")
+            .add("glGetObjectParameterARB")
+            .add("glGetObjectParameteriARB")
+            .add("glGetInfoLogARB")
+            .add("glGetHandleARB")
+            .add("glUniform1fARB", "glUniform1f")
+            .add("glUniform2fARB", "glUniform2f")
+            .add("glUniform3fARB", "glUniform3f")
+            .add("glUniform4fARB", "glUniform4f")
+            .add("glUniform1iARB", "glUniform1i")
+            .add("glUniform2iARB", "glUniform2i")
+            .add("glUniform3iARB", "glUniform3i")
+            .add("glUniform4iARB", "glUniform4i")
+            .add("glUniform1ARB", "glUniform1")
+            .add("glUniform2ARB", "glUniform2")
+            .add("glUniform3ARB", "glUniform3")
+            .add("glUniform4ARB", "glUniform4")
+            .add("glUniformMatrix2ARB", "glUniformMatrix2")
+            .add("glUniformMatrix3ARB", "glUniformMatrix3")
+            .add("glUniformMatrix4ARB", "glUniformMatrix4")
+            .add("glGetActiveUniformARB", "glGetActiveUniform")
+            .add("glGetAttachedObjectsARB", "glGetAttachedShaders")
+            .add("glGetShaderSourceARB", "glGetShaderSource")
+            .add("glGetUniformARB", "glGetUniform")
+        );
+        methodRedirects.put(ARBVertexArrayObject, RedirectMap.newMap()
+            .add("glBindVertexArray")
+            .add("glDeleteVertexArrays")
+        );
+        methodRedirects.put(ARBInstancedArrays, RedirectMap.newMap()
+            .add("glVertexAttribDivisorARB")
+        );
+        methodRedirects.put(ARBDrawInstanced, RedirectMap.newMap()
+            .add("glDrawArraysInstancedARB", "glDrawArraysInstanced")
+            .add("glDrawElementsInstancedARB", "glDrawElementsInstanced")
+        );
+        methodRedirects.put(EXTDrawInstanced, RedirectMap.newMap()
+            .add("glDrawArraysInstancedEXT", "glDrawArraysInstanced")
+            .add("glDrawElementsInstancedEXT", "glDrawElementsInstanced")
+        );
+        final var arbBufferObject = RedirectMap.newMap()
+            .add("glBindBufferARB", "glBindBuffer")
+            .add("glGenBuffersARB", "glGenBuffers")
+            .add("glDeleteBuffersARB", "glDeleteBuffers")
+            .add("glIsBufferARB", "glIsBuffer")
+            .add("glBufferDataARB", "glBufferData")
+            .add("glBufferSubDataARB", "glBufferSubData")
+            .add("glGetBufferSubDataARB", "glGetBufferSubData")
+            .add("glMapBufferARB", "glMapBuffer")
+            .add("glUnmapBufferARB", "glUnmapBuffer")
+            .add("glGetBufferParameterARB", "glGetBufferParameter")
+            .add("glGetBufferParameteriARB", "glGetBufferParameteri")
+            .add("glGetBufferParameterivARB", "glGetBufferParameteriv");
+        methodRedirects.put(ARBBufferObject, arbBufferObject);
+        methodRedirects.put(ARBVertexBufferObject, arbBufferObject);
+        methodRedirects.put(ARBBufferStorage, RedirectMap.newMap()
+            .add("glBufferStorage")
+        );
+        methodRedirects.put(ARBCopyBuffer, RedirectMap.newMap()
+            .add("glCopyBufferSubData")
+        );
+        methodRedirects.put(ARBMapBufferRange, RedirectMap.newMap()
+            .add("glMapBufferRange")
+            .add("glFlushMappedBufferRange")
+        );
+
+        // APPLE
+        methodRedirects.put(APPLEVertexArrayObject, RedirectMap.newMap()
+            .add("glBindVertexArrayAPPLE", "glBindVertexArray")
+        );
+
+        // GTNHLib VAO
+        methodRedirects.put(UniversalVAO, RedirectMap.newMap()
+            .add("bindVertexArray", "glBindVertexArray")
+            .add("deleteVertexArrays", "glDeleteVertexArrays")
+        );
+
+        // GLU
+        methodRedirects.put(Project, RedirectMap.newMap()
+            .add("gluPerspective")
+            .add("gluLookAt")
+            .add("gluPickMatrix")
+        );
+        methodRedirects.put(GLU, RedirectMap.newMap()
+            .add("gluPerspective")
+            .add("gluLookAt")
+            .add("gluOrtho2D")
+            .add("gluPickMatrix")
+        );
+
+        // Quadric type replacements
+        typeRedirects.put("org/lwjgl/util/glu/Sphere", "com/gtnewhorizons/angelica/glsm/compat/lwjgl/AngelicaSphere");
+        typeRedirects.put("org/lwjgl/util/glu/Cylinder", "com/gtnewhorizons/angelica/glsm/compat/lwjgl/AngelicaCylinder");
+        typeRedirects.put("org/lwjgl/util/glu/Disk", "com/gtnewhorizons/angelica/glsm/compat/lwjgl/AngelicaDisk");
+        typeRedirects.put("org/lwjgl/util/glu/PartialDisk", "com/gtnewhorizons/angelica/glsm/compat/lwjgl/AngelicaPartialDisk");
+
+        // Build constant pool scanner
+        final List<String> stringsToSearch = new ArrayList<>(32);
+        stringsToSearch.add(GL_PREFIX);
+        stringsToSearch.addAll(typeRedirects.keySet());
+        for (String key : methodRedirects.keySet()) {
+            stringsToSearch.add(key);
+        }
+        cstPoolParser = new ClassConstantPoolParser(stringsToSearch.toArray(new String[0]));
+    }
+
+    /** Core exclusions that GLSM always requires. */
+    public String[] getCoreExclusions() {
+        return CORE_EXCLUSIONS.clone();
+    }
+
+    /** The internal-name prefix used to match GL version classes (e.g., {@code "org/lwjgl/opengl/GL"}). */
+    public static String getGLPrefix() { return GL_PREFIX; }
+
+    /** The internal name of the redirect target class. */
+    public static String getTargetClassName() { return GLStateManager; }
+
+    /** Method redirects for GL-prefix classes. Key: original method name, Value: GLStateManager method name. */
+    public static Map<String, String> getGLPrefixMethodRedirects() {
+        return Collections.unmodifiableMap(glMethodRedirects);
+    }
+
+    /** Method redirects for named (non-GL-prefix) classes. Key: internal class name, Value: per-method redirect map. */
+    public static Map<String, Map<String, String>> getNamedClassMethodRedirects() {
+        return Collections.unmodifiableMap(methodRedirects);
+    }
+
+    public boolean shouldTransform(byte[] basicClass) {
+        return cstPoolParser.find(basicClass, true);
+    }
+
+    /** @return Was the class changed? */
+    public boolean transformClassNode(String transformedName, ClassNode cn) {
+        boolean changed = false;
+        final boolean isOpenGlHelper = transformedName.equals("net.minecraft.client.renderer.OpenGlHelper");
+
+        for (MethodNode mn : (List<MethodNode>) cn.methods) {
+            if (isOpenGlHelper && (mn.name.equals("glBlendFunc") || mn.name.equals("func_148821_a"))) {
+                continue;
+            }
+            boolean redirectInMethod = false;
+            for (AbstractInsnNode node : mn.instructions.toArray()) {
+                if (node instanceof TypeInsnNode tNode) {
+                    // Redirect NEW and CHECKCAST for quadric classes
+                    if (tNode.getOpcode() == Opcodes.NEW || tNode.getOpcode() == Opcodes.CHECKCAST) {
+                        final String redirect = typeRedirects.get(tNode.desc);
+                        if (redirect != null) {
+                            if (LOG_SPAM) {
+                                LOGGER.info("Redirecting {} in {} from {} to {}", tNode.getOpcode() == Opcodes.NEW ? "NEW" : "CHECKCAST", transformedName, tNode.desc, redirect);
+                            }
+                            tNode.desc = redirect;
+                            changed = true;
+                        }
+                    }
+                } else if (node instanceof MethodInsnNode mNode) {
+                    if (mNode.desc.equals("(I)V") && mNode.owner.startsWith(GL_PREFIX) && (mNode.name.equals("glEnable") || mNode.name.equals("glDisable"))) {
+                        final AbstractInsnNode prevNode = node.getPrevious();
+                        String name = null;
+                        if (prevNode instanceof LdcInsnNode ldcNode) {
+                            name = glCapRedirects.get(((Integer) ldcNode.cst));
+                        } else if (prevNode instanceof IntInsnNode intNode) {
+                            name = glCapRedirects.get(intNode.operand);
+                        }
+                        if (name != null) {
+                            if (mNode.name.equals("glEnable")) {
+                                name = "enable" + name;
+                            } else {
+                                name = "disable" + name;
+                            }
+                        }
+                        if (LOG_SPAM) {
+                            final String shortOwner = mNode.owner.substring(mNode.owner.lastIndexOf("/") + 1);
+                            if (name == null) {
+                                LOGGER.info("Redirecting call in {} from {}.{}(I)V to GLStateManager.{}(I)V", transformedName, shortOwner, mNode.name, mNode.name);
+                            } else {
+                                LOGGER.info("Redirecting call in {} from {}.{}(I)V to GLStateManager.{}()V", transformedName, shortOwner, mNode.name, name);
+                            }
+                        }
+                        mNode.owner = GLStateManager;
+                        if (name != null) {
+                            mNode.name = name;
+                            mNode.desc = "()V";
+                            mn.instructions.remove(prevNode);
+                        }
+                        changed = true;
+                        redirectInMethod = true;
+                    } else if (mNode.name.equals("makeCurrent") && mNode.owner.startsWith(Drawable)) {
+                        mNode.setOpcode(Opcodes.INVOKESTATIC);
+                        mNode.owner = GLStateManager;
+                        mNode.desc = "(L" + Drawable + ";)V";
+                        mNode.itf = false;
+                        changed = true;
+                        if (LOG_SPAM) {
+                            LOGGER.info("Redirecting call in {} to GLStateManager.makeCurrent()", transformedName);
+                        }
+                    } else {
+                        final Map<String, String> redirects = mNode.owner.startsWith(GL_PREFIX) ? glMethodRedirects : methodRedirects.get(mNode.owner);
+                        final String glsmName = redirects != null ? redirects.get(mNode.name) : null;
+                        if (glsmName != null) {
+                            if (LOG_SPAM) {
+                                final String shortOwner = mNode.owner.substring(mNode.owner.lastIndexOf("/") + 1);
+                                LOGGER.info("Redirecting call in {} from {}.{}{} to GLStateManager.{}{}", transformedName, shortOwner, mNode.name, mNode.desc, glsmName, mNode.desc);
+                            }
+                            mNode.owner = GLStateManager;
+                            mNode.name = glsmName;
+                            changed = true;
+                            redirectInMethod = true;
+                        }
+                    }
+                    // Redirect <init> calls for quadric classes
+                    if (mNode.getOpcode() == Opcodes.INVOKESPECIAL && mNode.name.equals("<init>")) {
+                        final String redirect = typeRedirects.get(mNode.owner);
+                        if (redirect != null) {
+                            if (LOG_SPAM) {
+                                LOGGER.info("Redirecting <init> in {} from {} to {}", transformedName, mNode.owner, redirect);
+                            }
+                            mNode.owner = redirect;
+                            changed = true;
+                        }
+                    }
+                } else if (node instanceof InvokeDynamicInsnNode dynNode) {
+                    // Redirect method handles in invokedynamic bootstrap arguments
+                    for (int i = 0; i < dynNode.bsmArgs.length; i++) {
+                        if (!(dynNode.bsmArgs[i] instanceof Handle handle)) continue;
+                        final Map<String, String> redirects = handle.getOwner().startsWith(GL_PREFIX) ? glMethodRedirects : methodRedirects.get(handle.getOwner());
+                        final String glsmName = redirects != null ? redirects.get(handle.getName()) : null;
+                        if (glsmName == null) continue;
+                        if (LOG_SPAM) {
+                            final String shortOwner = handle.getOwner().substring(handle.getOwner().lastIndexOf("/") + 1);
+                            LOGGER.info("Redirecting invokedynamic handle in {} from {}.{}{} to GLStateManager.{}{}", transformedName, shortOwner, handle.getName(), handle.getDesc(), glsmName, handle.getDesc());
+                        }
+                        dynNode.bsmArgs[i] = new Handle(handle.getTag(), GLStateManager, glsmName, handle.getDesc());
+                        changed = true;
+                        redirectInMethod = true;
+                    }
+                }
+            }
+            if (ASSERT_MAIN_THREAD && redirectInMethod && !transformedName.startsWith(SplashProgress) && !(transformedName.startsWith(MinecraftClient) && ExcludedMinecraftMainThreadChecks.contains(mn.name))) {
+                mn.instructions.insert(new MethodInsnNode(Opcodes.INVOKESTATIC, GLStateManager, "assertMainThread", "()V", false));
+            }
+        }
+
+        return changed;
+    }
+
+    private static final class RedirectMap<K> extends HashMap<K, K> {
+
+        public static RedirectMap<String> newMap() {
+            return new RedirectMap<>();
+        }
+
+        public RedirectMap<K> add(K name) {
+            this.put(name, name);
+            return this;
+        }
+
+        public RedirectMap<K> add(K name, K newName) {
+            this.put(name, newName);
+            return this;
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/BooleanStateStack.java

@@ -0,0 +1,128 @@
+package com.gtnewhorizons.angelica.glsm.stacks;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.states.BooleanState;
+
+/**
+ * A stack for boolean GL state with lazy copy-on-write optimization.
+ * <p>
+ * When using the global attrib depth tracking (from glPushAttrib/glPopAttrib), state is only
+ * saved when actually modified, dramatically reducing overhead when most states
+ * don't change (e.g., GL_ENABLE_BIT saves ~270 states but typically only 3-4 change).
+ */
+public class BooleanStateStack extends BooleanState implements IStateStack<BooleanStateStack> {
+
+    protected final boolean[] stack;
+
+    /**
+     * The depth at which state has been saved. Compared against GLStateManager.getAttribDepth()
+     * to determine if we need to save before modification or restore on pop.
+     */
+    protected int savedDepth;
+
+    public BooleanStateStack(int glCap) {
+        this(glCap, false, false);
+    }
+
+    /**
+     * Create a BooleanStateStack with a custom initial state.
+     * Useful for GL states that default to true (e.g., GL_DITHER, GL_MULTISAMPLE).
+     *
+     * @param glCap GL capability constant
+     * @param initialState initial enabled state
+     */
+    public BooleanStateStack(int glCap, boolean initialState) {
+        this(glCap, initialState, false);
+    }
+
+    /**
+     * Create a BooleanStateStack with custom initial state and FFP flag.
+     *
+     * @param glCap GL capability constant
+     * @param initialState initial enabled state
+     * @param ffpStateOnly when true, GL calls are skipped when FFP emulation is active
+     */
+    public BooleanStateStack(int glCap, boolean initialState, boolean ffpStateOnly) {
+        super(glCap, ffpStateOnly);
+        this.enabled = initialState;
+        stack = new boolean[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
+    }
+
+    // ==================== Traditional Stack Operations ====================
+
+    @Override
+    public BooleanStateStack push() {
+        if (savedDepth >= stack.length) {
+            throw new IllegalStateException("Stack overflow size " + (savedDepth + 1) + " reached");
+        }
+        stack[savedDepth++] = enabled;
+        return this;
+    }
+
+    @Override
+    public BooleanStateStack pop() {
+        if (savedDepth == 0) {
+            throw new IllegalStateException("Stack underflow");
+        }
+        final boolean oldValue = stack[--savedDepth];
+        // Call setEnabledDirect to avoid triggering beforeModify during restore
+        setEnabledDirect(oldValue);
+        return this;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return savedDepth == 0;
+    }
+
+    // ==================== Lazy Copy-on-Write Operations ====================
+
+    @Override
+    public int pushDepth() {
+        // No-op: global depth is managed by GLStateManager
+        return GLStateManager.getAttribDepth();
+    }
+
+    /**
+     * Restore state if it was modified at the current depth.
+     * Only called by GLStateManager.popState() for states that registered as modified.
+     */
+    @Override
+    public BooleanStateStack popDepth() {
+        // We're only called if we were modified, so savedDepth should match
+        if (savedDepth > 0) {
+            final boolean oldValue = stack[--savedDepth];
+            setEnabledDirect(oldValue);
+        }
+        return this;
+    }
+
+    /**
+     * Called before modifying state. If we haven't saved at the current depth yet,
+     * save the current value and register with GLStateManager for restoration.
+     */
+    @Override
+    public void beforeModify() {
+        final int globalDepth = GLStateManager.getAttribDepth();
+        if (savedDepth < globalDepth) {
+            stack[savedDepth++] = enabled;
+            GLStateManager.registerModifiedState(this);
+        }
+    }
+
+    @Override
+    public int getDepth() {
+        return GLStateManager.getAttribDepth();
+    }
+
+    @Override
+    public void setEnabled(boolean enabled) {
+        beforeModify();
+        super.setEnabled(enabled);
+    }
+
+    private void setEnabledDirect(boolean enabled) {
+        super.setEnabled(enabled);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/LineStateStack.java

@@ -0,0 +1,42 @@
+package com.gtnewhorizons.angelica.glsm.stacks;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.states.LineState;
+
+/**
+ * Stack for GL line state (width, stipple factor, stipple pattern).
+ * Used by GL_LINE_BIT push/pop attrib.
+ */
+public class LineStateStack extends LineState implements IStateStack<LineStateStack> {
+
+    protected final LineState[] stack;
+    protected int pointer;
+
+    public LineStateStack() {
+        stack = new LineState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
+        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+            stack[i] = new LineState();
+        }
+    }
+
+    public LineStateStack push() {
+        if (pointer == stack.length) {
+            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
+        }
+        stack[pointer++].set(this);
+        return this;
+    }
+
+    public LineStateStack pop() {
+        if (pointer == 0) {
+            throw new IllegalStateException("Stack underflow");
+        }
+        set(stack[--pointer]);
+        return this;
+    }
+
+    public boolean isEmpty() {
+        return pointer == 0;
+    }
+}