Fix/bug fixes (#1905)

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

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,14 @@
+# Description or 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

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

@@ -23,7 +23,7 @@ Targets GL 3.3+ core profile
 
 # Required Dependencies
 * [UniMixins](https://github.com/LegacyModdingMC/UniMixins/releases) >= 0.1.23
-* [GTNHLib](https://github.com/GTNewHorizons/GTNHLib/releases) >= 0.9.0
+* [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
@@ -50,6 +50,7 @@ Targets GL 3.3+ core profile
 * 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

build.gradle.kts

@@ -1,12 +1,19 @@
+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")
@@ -19,8 +26,7 @@ tasks.test {
         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"
+    val isMacOsArm64 = System.getProperty("os.name").lowercase().contains("mac") && System.getProperty("os.arch") == "aarch64"
     javaLauncher = javaToolchains.launcherFor {
         languageVersion = JavaLanguageVersion.of(8)
         if (isMacOsArm64) {
@@ -47,22 +53,49 @@ tasks.register<Copy>("copyDependencies") {
 }
 
 val embedOnly: Configuration by configurations
+val shadowImplementation: Configuration by configurations
 
-// Downgrade embedOnly jars for the tests
 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)
+    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

@@ -47,6 +47,8 @@ configurations {
     // 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
@@ -54,6 +56,7 @@ configurations {
     compileClasspath.extendsFrom(embedOnly)
     testCompileClasspath.extendsFrom(embedOnly)
     testRuntimeClasspath.extendsFrom(embedOnly)
+
 }
 
 
@@ -63,32 +66,57 @@ configurations.all {
 }
 
 dependencies {
-    compileOnly("com.github.GTNewHorizons:Hodgepodge:2.7.14:dev")
+    compileOnly("com.github.GTNewHorizons:Hodgepodge:2.7.158:dev")
 
-    compileOnly("com.gtnewhorizons.retrofuturabootstrap:RetroFuturaBootstrap:1.0.7") { transitive = false }
+    compileOnly("com.gtnewhorizons.retrofuturabootstrap:RetroFuturaBootstrap:1.1.0") { transitive = false }
+//    runtimeOnlyNonPublishable("com.github.GTNewHorizons:lwjgl3ify:3.0.99")
 
     compileOnly("org.projectlombok:lombok:1.18.42") { transitive = false }
     annotationProcessor("org.projectlombok:lombok:1.18.42")
 
     // Iris Shaders
     compileOnly('org.jetbrains:annotations:26.0.2')
-    api("com.github.GTNewHorizons:GTNHLib:0.9.36:dev")
+    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:0.2.0-26.g5ee7d96-GTNH") {
+    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:2.5.2-GTNH") { transitive = false }
-    embedOnly("org.embeddedt.celeritas:celeritas-lwjgl2-service:2.5.2-GTNH") { transitive = false }
+    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:2.8.35-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-Expanded:2.2.2-GTNH:dev")
@@ -111,12 +139,15 @@ dependencies {
 
     compileOnly("com.github.GTNewHorizons:NotEnoughIds:2.1.10:dev")
 
-    compileOnly(rfg.deobf("maven.modrinth:ntmspace:X5593_H261"))
+    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(rfg.deobf("curse.maven:et-futurum-requiem-441392:5873837"))
+    compileOnly(rfg.deobf("curse.maven:biomes-o-plenty-220318:2499612"))
+
+    devOnlyNonPublishable("com.github.GTNewHorizons:CosmeticArmorReworked:1.0.3-GTNH:dev")
 
     // For testing alternative splash screens — https://github.com/MalTeeez/ModernSplash/releases
     // devOnlyNonPublishable("com.github.MalTeeez:modernsplash:1.7.10-1.2.4:dev")
@@ -127,6 +158,9 @@ dependencies {
     // Better Crashes
     compileOnly("com.github.GTNewHorizons:BetterCrashes:1.4.1-GTNH:dev")
 
+    // Distant Horizons
+    compileOnly("maven.modrinth:DistantHorizonsApi:5.1.0")
+
     afterEvaluate {
         dependencies {
             testImplementation(platform('org.junit:junit-bom:5.14.1'))
@@ -137,8 +171,15 @@ dependencies {
             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

@@ -1,6 +1,10 @@
 package com.gtnewhorizons.angelica.glsm;
 
-import net.minecraft.launchwrapper.Launch;
+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;
 
@@ -9,16 +13,18 @@ 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.loading.AngelicaTweaker.LOGGER;
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
 
 /**
  * Compat transformation for mod shaders running under core profile.
@@ -39,13 +45,11 @@ import static com.gtnewhorizons.angelica.loading.AngelicaTweaker.LOGGER;
  */
 public class CompatShaderTransformer {
 
-    private static final Pattern VERSION_PATTERN =
-        Pattern.compile("#version\\s+(\\d+)(?:\\s+(\\w+))?");
+    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+.+$", Pattern.MULTILINE);
+    private static final Pattern DEFINE_PATTERN = Pattern.compile("^\\s*#\\s*define\\s+.+$", Pattern.MULTILINE);
 
-    /** Compat builtins that trigger AST transformation.  */
+    /** 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",
@@ -69,14 +73,9 @@ public class CompatShaderTransformer {
 
     private static final Path DUMP_DIR;
     private static final AtomicInteger dumpCounter = new AtomicInteger(0);
+
     static {
-        boolean isDev = false;
-        try {
-            final Object deobfEnv = Launch.blackboard != null ? Launch.blackboard.get("fml.deobfuscatedEnvironment") : null;
-            isDev = Boolean.TRUE.equals(deobfEnv);
-        } catch (Exception ignored) {}
-        DUMP_DIR = (isDev || Boolean.parseBoolean(System.getProperty("angelica.compat.dumpShaders", "false")))
-            ? Paths.get("compat_shaders") : null;
+        DUMP_DIR = Boolean.parseBoolean(System.getProperty("angelica.dumpShaders", "false")) ? Paths.get("compat_shaders") : null;
     }
 
     private static final int CACHE_SIZE = 32;
@@ -84,9 +83,9 @@ public class CompatShaderTransformer {
     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;
-            }
-        });
+            return size() > CACHE_SIZE;
+        }
+    });
 
     public static void clearCache() {
         cache.clear();
@@ -112,7 +111,7 @@ public class CompatShaderTransformer {
                 result = transformInternal(source, isFragment);
                 cache.put(key, result);
             } catch (Exception e) {
-                LOGGER.warn("CompatShaderTransformer: AST transformation failed, falling back to version fixup only", e);
+                GLStateManager.LOGGER.warn("CompatShaderTransformer: AST transformation failed, falling back to version fixup only", e);
                 result = fixupVersion(source);
             }
         }
@@ -121,13 +120,17 @@ public class CompatShaderTransformer {
         return result;
     }
 
-    private static boolean needsTransformation(String source) {
-        // Shaders already at 330+ core don't need compat transformation
+    public static boolean isCoreShader(String source) {
         final Matcher vm = VERSION_PATTERN.matcher(source);
         if (vm.find()) {
             final int version = Integer.parseInt(vm.group(1));
-            if (version >= 330 && "core".equals(vm.group(2))) return false;
+            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();
     }
@@ -139,7 +142,7 @@ public class CompatShaderTransformer {
             declaredVersion = Integer.parseInt(versionMatcher.group(1));
         }
 
-        final int targetVersion = Math.max(declaredVersion, 330);
+        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);
@@ -160,22 +163,20 @@ public class CompatShaderTransformer {
 
         // 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("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("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");
         }
@@ -188,8 +189,9 @@ public class CompatShaderTransformer {
             transformer.rename("gl_FrontColor", "angelica_FrontColor");
             transformer.prependMain("angelica_FrontColor = vec4(1.0);");
 
-            // Vertex attributes — replaces removed FFP vertex inputs with explicit in declarations
-            transformVertexAttributes(transformer, source);
+            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;");
@@ -263,7 +265,9 @@ public class CompatShaderTransformer {
         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))");
+        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))");
     }
 
     /**
@@ -306,34 +310,33 @@ public class CompatShaderTransformer {
         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));");
+        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) {
-        if (source.contains("gl_Vertex") || source.contains("ftransform")) {
+    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 (source.contains("gl_Color")) {
+        if (ffp.color()) {
             transformer.injectVariable("layout(location = 1) in vec4 angelica_Color;");
             transformer.rename("gl_Color", "angelica_Color");
         }
-        if (source.contains("gl_MultiTexCoord0")) {
+        if (ffp.uv0()) {
             transformer.injectVariable("layout(location = 2) in vec4 angelica_MultiTexCoord0;");
             transformer.rename("gl_MultiTexCoord0", "angelica_MultiTexCoord0");
         }
-        if (source.contains("gl_MultiTexCoord1")) {
+        if (ffp.uv1()) {
             transformer.injectVariable("layout(location = 3) in vec4 angelica_MultiTexCoord1;");
             transformer.rename("gl_MultiTexCoord1", "angelica_MultiTexCoord1");
         }
-        if (source.contains("gl_Normal")) {
+        if (ffp.normal()) {
             transformer.injectVariable("layout(location = 4) in vec3 angelica_Normal;");
             transformer.rename("gl_Normal", "angelica_Normal");
         }
@@ -342,6 +345,145 @@ public class CompatShaderTransformer {
         }
     }
 
+    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();
@@ -356,7 +498,7 @@ public class CompatShaderTransformer {
             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) {
-            LOGGER.warn("Failed to dump compat shader: {}", e.getMessage());
+            GLStateManager.LOGGER.warn("Failed to dump compat shader: {}", e.getMessage());
         }
     }
 

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

@@ -9,18 +9,19 @@ 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 org.lwjgl.opengl.GL20;
 
 import java.nio.FloatBuffer;
 
-import static com.gtnewhorizons.angelica.loading.AngelicaTweaker.LOGGER;
+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.
+ * <p>Manages {@code angelica_*} uniforms injected by {@link CompatShaderTransformer} and {@code iris_*} matrix uniforms used by Iris/celeritas shader
+ * programs.
  */
 public class CompatUniformManager {
 
@@ -39,10 +40,11 @@ public class CompatUniformManager {
     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_ALPHA_TEST_REF = 14;
-    static final int LOC_SCENE_COLOR = 15;
-    static final int LOC_CLIP_PLANES = 16;
-    static final int LOC_CLIP_PLANES_ENABLED = 17;
+    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;
@@ -50,14 +52,17 @@ public class CompatUniformManager {
     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 = 18;
+    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; // 42
+    static final int LOC_MAT_BASE = LOC_LIGHT_BASE + 2 * LIGHT_FIELDS; // 43
 
-    static final int LOC_COUNT = LOC_MAT_BASE + MAT_FIELDS; // 47
+    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",
@@ -69,6 +74,7 @@ public class CompatUniformManager {
     };
 
     private static final String[] UNIFORM_NAMES;
+
     static {
         UNIFORM_NAMES = new String[LOC_COUNT];
         UNIFORM_NAMES[LOC_MODELVIEW] = "angelica_ModelViewMatrix";
@@ -85,14 +91,16 @@ public class CompatUniformManager {
         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];
+                UNIFORM_NAMES[LOC_LIGHT_BASE + li * LIGHT_FIELDS + fi] = "angelica_LightSource[" + li + "]." + LIGHT_FIELD_NAMES[fi];
             }
         }
         for (int fi = 0; fi < MAT_FIELDS; fi++) {
@@ -100,8 +108,15 @@ public class CompatUniformManager {
         }
     }
 
-    /** Per-program cached uniform locations. Maps program ID → int[LOC_COUNT]. */
-    private static final Int2ObjectOpenHashMap<int[]> programLocations = new Int2ObjectOpenHashMap<>();
+    /** 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);
@@ -110,74 +125,81 @@ public class CompatUniformManager {
     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);
     }
 
-    // Dirty tracking: skip uploads when state hasn't changed and program is the same
-    private static int lastProgram = -1;
-    private static int lastMvGen = -1;
-    private static int lastProjGen = -1;
-    private static int lastTexMatGen = -1;
-    private static int lastFragmentGen = -1;
-    private static int lastLightingGen = -1;
-    private static int lastClipPlaneGen = -1;
-
     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] = GL20.glGetUniformLocation(program, UNIFORM_NAMES[i]);
+            locs[i] = RENDER_BACKEND.getUniformLocation(program, UNIFORM_NAMES[i]);
             if (locs[i] != -1) hasAny = true;
         }
 
         if (hasAny) {
-            programLocations.put(program, locs);
-            LOGGER.debug("CompatUniformManager: program {} has compat uniforms", program);
+            programUniforms.put(program, new ProgramUniforms(locs));
+            GLStateManager.LOGGER.debug("CompatUniformManager: program {} has compat uniforms", program);
         }
     }
 
-    public static void onUseProgram(int program) {
-        if (program == 0) return;
+    /**
+     * 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;
 
-        int[] locs = programLocations.get(program);
-        if (locs == null) return;
-
-        final boolean programChanged = program != lastProgram;
-        lastProgram = program;
-
-        // Matrix uniforms — skip if generation unchanged and same program
+        // 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 = programChanged || mvGen != lastMvGen;
-        final boolean projChanged = programChanged || projGen != lastProjGen;
-        final boolean texMatChanged = programChanged || texMatGen != lastTexMatGen;
+        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, projChanged, texMatChanged);
-            lastMvGen = mvGen;
-            lastProjGen = projGen;
-            lastTexMatGen = texMatGen;
+            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 (programChanged || fragGen != lastFragmentGen) {
-            lastFragmentGen = fragGen;
+        if (fragGen != pu.lastFragmentGen) {
+            pu.lastFragmentGen = fragGen;
             uploadFragmentUniforms(locs);
         }
 
         // Lighting-derived uniforms (scene color, light sources, material)
         final int litGen = GLStateManager.lightingGeneration;
-        if (programChanged || litGen != lastLightingGen) {
-            lastLightingGen = litGen;
+        if (litGen != pu.lastLightingGen) {
+            pu.lastLightingGen = litGen;
             if (locs[LOC_SCENE_COLOR] != -1) uploadSceneColor(locs);
             uploadLightSources(locs);
             uploadMaterial(locs);
@@ -186,14 +208,16 @@ public class CompatUniformManager {
         // 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 (programChanged || cpGen != lastClipPlaneGen) {
-                lastClipPlaneGen = cpGen;
+            if (cpGen != pu.lastClipPlaneGen) {
+                pu.lastClipPlaneGen = cpGen;
                 uploadClipPlanes(locs);
             }
         }
+
+        return true;
     }
 
-    private static void uploadMatrices(int[] locs, boolean mvChanged, boolean projChanged, boolean texMatChanged) {
+    private static void uploadMatrices(int[] locs, boolean mvChanged, boolean mvLinearChanged, boolean projChanged, boolean texMatChanged) {
         final Matrix4f mv = GLStateManager.getModelViewMatrix();
         final Matrix4f proj = GLStateManager.getProjectionMatrix();
 
@@ -202,29 +226,39 @@ public class CompatUniformManager {
             if (locs[LOC_MODELVIEW] != -1 || locs[LOC_IRIS_MODELVIEW] != -1) {
                 mv.get(mat4Buf);
                 if (locs[LOC_MODELVIEW] != -1) {
-                    GL20.glUniformMatrix4(locs[LOC_MODELVIEW], false, mat4Buf);
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_MODELVIEW], false, mat4Buf);
                 }
                 if (locs[LOC_IRIS_MODELVIEW] != -1) {
-                    GL20.glUniformMatrix4(locs[LOC_IRIS_MODELVIEW], false, mat4Buf);
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_MODELVIEW], false, mat4Buf);
                 }
             }
 
             // ModelView Inverse
-            if (locs[LOC_MODELVIEW_INVERSE] != -1) {
+            if (locs[LOC_MODELVIEW_INVERSE] != -1 || locs[LOC_IRIS_MODELVIEW_INVERSE] != -1) {
                 mv.invert(scratchMatrix);
                 scratchMatrix.get(mat4Buf);
-                GL20.glUniformMatrix4(locs[LOC_MODELVIEW_INVERSE], false, 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);
-                normalMatrix.get(mat3Buf);
                 if (locs[LOC_NORMAL] != -1) {
-                    GL20.glUniformMatrix3(locs[LOC_NORMAL], false, mat3Buf);
+                    normalMatrix.get(mat3Buf);
+                    RENDER_BACKEND.uniformMatrix3(locs[LOC_NORMAL], false, mat3Buf);
                 }
+                // Column-normalized to unit magnitude
                 if (locs[LOC_IRIS_NORMAL] != -1) {
-                    GL20.glUniformMatrix3(locs[LOC_IRIS_NORMAL], false, mat3Buf);
+                    normalizeColumnsInPlace(normalMatrix);
+                    normalMatrix.get(mat3Buf);
+                    RENDER_BACKEND.uniformMatrix3(locs[LOC_IRIS_NORMAL], false, mat3Buf);
                 }
             }
         }
@@ -234,31 +268,42 @@ public class CompatUniformManager {
             if (locs[LOC_PROJECTION] != -1 || locs[LOC_IRIS_PROJECTION] != -1) {
                 proj.get(mat4Buf);
                 if (locs[LOC_PROJECTION] != -1) {
-                    GL20.glUniformMatrix4(locs[LOC_PROJECTION], false, mat4Buf);
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_PROJECTION], false, mat4Buf);
                 }
                 if (locs[LOC_IRIS_PROJECTION] != -1) {
-                    GL20.glUniformMatrix4(locs[LOC_IRIS_PROJECTION], false, mat4Buf);
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_PROJECTION], false, mat4Buf);
                 }
             }
 
             // Projection Inverse
-            if (locs[LOC_PROJECTION_INVERSE] != -1) {
+            if (locs[LOC_PROJECTION_INVERSE] != -1 || locs[LOC_IRIS_PROJECTION_INVERSE] != -1) {
                 proj.invert(scratchMatrix);
                 scratchMatrix.get(mat4Buf);
-                GL20.glUniformMatrix4(locs[LOC_PROJECTION_INVERSE], false, 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) {
-                GL20.glUniformMatrix4(locs[LOC_IRIS_LIGHTMAP_TEXTURE_MATRIX], false, lightmapMatrixBuf);
+                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);
-                GL20.glUniformMatrix4(locs[LOC_LIGHTMAP_TEXTURE_MATRIX], false, 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);
             }
         }
     }
@@ -267,39 +312,36 @@ public class CompatUniformManager {
         // Fog uniforms
         FogStateStack fog = GLStateManager.getFogState();
         if (locs[LOC_FOG_DENSITY] != -1) {
-            GL20.glUniform1f(locs[LOC_FOG_DENSITY], Math.max(0.0f, fog.getDensity()));
+            RENDER_BACKEND.uniform1f(locs[LOC_FOG_DENSITY], Math.max(0.0f, fog.getDensity()));
         }
         if (locs[LOC_FOG_START] != -1) {
-            GL20.glUniform1f(locs[LOC_FOG_START], fog.getStart());
+            RENDER_BACKEND.uniform1f(locs[LOC_FOG_START], fog.getStart());
         }
         if (locs[LOC_FOG_END] != -1) {
-            GL20.glUniform1f(locs[LOC_FOG_END], fog.getEnd());
+            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.put((float) fog.getFogColor().x).put((float) fog.getFogColor().y).put((float) fog.getFogColor().z).put(fog.getFogAlpha());
             vec4Buf.flip();
-            GL20.glUniform4(locs[LOC_FOG_COLOR], vec4Buf);
+            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) {
+            if (!GLStateManager.getAlphaTest().isEnabled() || GLStateManager.getAlphaState().getFunction() == GL11.GL_ALWAYS) {
                 ref = -1.0f;
             } else {
                 ref = GLStateManager.getAlphaState().getReference();
             }
-            GL20.glUniform1f(locs[LOC_ALPHA_TEST_REF], ref);
+            RENDER_BACKEND.uniform1f(locs[LOC_ALPHA_TEST_REF], ref);
         }
     }
 
     /**
-     * Scene color = emission + ambient * lightModel.ambient, alpha = diffuse.a
-     * Same computation as {@code Uniforms.uploadLightingPreComputed()}.
+     * 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();
@@ -310,7 +352,7 @@ public class CompatUniformManager {
                .put(mat.emission.z + mat.ambient.z * lm.ambient.z)
                .put(mat.diffuse.w);
         vec4Buf.flip();
-        GL20.glUniform4(locs[LOC_SCENE_COLOR], vec4Buf);
+        RENDER_BACKEND.uniform4(locs[LOC_SCENE_COLOR], vec4Buf);
     }
 
     private static void uploadLightSources(int[] locs) {
@@ -322,19 +364,20 @@ public class CompatUniformManager {
             final LightState light = lights[li];
 
             if (locs[base + LF_AMBIENT] != -1)
-                GL20.glUniform4f(locs[base + LF_AMBIENT], light.ambient.x, light.ambient.y, light.ambient.z, light.ambient.w);
+                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)
-                GL20.glUniform4f(locs[base + LF_DIFFUSE], light.diffuse.x, light.diffuse.y, light.diffuse.z, light.diffuse.w);
+                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)
-                GL20.glUniform4f(locs[base + LF_SPECULAR], light.specular.x, light.specular.y, light.specular.z, light.specular.w);
+                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)
-                GL20.glUniform4f(locs[base + LF_POSITION], light.position.x, light.position.y, light.position.z, light.position.w);
+                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) {
-                    float len = (float) Math.sqrt(light.position.x * light.position.x
-                        + light.position.y * light.position.y + light.position.z * light.position.z);
+                    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;
@@ -345,24 +388,17 @@ public class CompatUniformManager {
                 } else {
                     hx = 0; hy = 0; hz = 1;
                 }
-                float hlen = (float) Math.sqrt(hx * hx + hy * hy + hz * hz);
+                final float hlen = (float) Math.sqrt(hx * hx + hy * hy + hz * hz);
                 if (hlen > 0) { hx /= hlen; hy /= hlen; hz /= hlen; }
-                GL20.glUniform4f(locs[base + LF_HALF_VECTOR], hx, hy, hz, 0.0f);
+                RENDER_BACKEND.uniform4f(locs[base + LF_HALF_VECTOR], hx, hy, hz, 0.0f);
             }
-            if (locs[base + LF_SPOT_DIRECTION] != -1)
-                GL20.glUniform3f(locs[base + LF_SPOT_DIRECTION], light.spotDirection.x, light.spotDirection.y, light.spotDirection.z);
-            if (locs[base + LF_SPOT_EXPONENT] != -1)
-                GL20.glUniform1f(locs[base + LF_SPOT_EXPONENT], light.spotExponent);
-            if (locs[base + LF_SPOT_CUTOFF] != -1)
-                GL20.glUniform1f(locs[base + LF_SPOT_CUTOFF], light.spotCutoff);
-            if (locs[base + LF_SPOT_COS_CUTOFF] != -1)
-                GL20.glUniform1f(locs[base + LF_SPOT_COS_CUTOFF], light.spotCosCutoff);
-            if (locs[base + LF_CONSTANT_ATTEN] != -1)
-                GL20.glUniform1f(locs[base + LF_CONSTANT_ATTEN], light.constantAttenuation);
-            if (locs[base + LF_LINEAR_ATTEN] != -1)
-                GL20.glUniform1f(locs[base + LF_LINEAR_ATTEN], light.linearAttenuation);
-            if (locs[base + LF_QUADRATIC_ATTEN] != -1)
-                GL20.glUniform1f(locs[base + LF_QUADRATIC_ATTEN], light.quadraticAttenuation);
+            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);
         }
     }
 
@@ -371,20 +407,20 @@ public class CompatUniformManager {
         if (locs[LOC_MAT_BASE] == -1) return;
         final MaterialState mat = GLStateManager.getFrontMaterial();
         if (locs[LOC_MAT_BASE + MF_EMISSION] != -1)
-            GL20.glUniform4f(locs[LOC_MAT_BASE + MF_EMISSION], mat.emission.x, mat.emission.y, mat.emission.z, mat.emission.w);
+            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)
-            GL20.glUniform4f(locs[LOC_MAT_BASE + MF_AMBIENT], mat.ambient.x, mat.ambient.y, mat.ambient.z, mat.ambient.w);
+            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)
-            GL20.glUniform4f(locs[LOC_MAT_BASE + MF_DIFFUSE], mat.diffuse.x, mat.diffuse.y, mat.diffuse.z, mat.diffuse.w);
+            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)
-            GL20.glUniform4f(locs[LOC_MAT_BASE + MF_SPECULAR], mat.specular.x, mat.specular.y, mat.specular.z, mat.specular.w);
+            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)
-            GL20.glUniform1f(locs[LOC_MAT_BASE + MF_SHININESS], mat.shininess);
+            RENDER_BACKEND.uniform1f(locs[LOC_MAT_BASE + MF_SHININESS], mat.shininess);
     }
 
     private static void uploadClipPlanes(int[] locs) {
         if (locs[LOC_CLIP_PLANES_ENABLED] != -1) {
-            GL20.glUniform1i(locs[LOC_CLIP_PLANES_ENABLED], GLStateManager.anyClipPlaneEnabled() ? 1 : 0);
+            RENDER_BACKEND.uniform1i(locs[LOC_CLIP_PLANES_ENABLED], GLStateManager.anyClipPlaneEnabled() ? 1 : 0);
         }
         if (locs[LOC_CLIP_PLANES] != -1) {
             final ClipPlaneState cps = GLStateManager.getClipPlaneState();
@@ -393,19 +429,20 @@ public class CompatUniformManager {
                 cps.putEyePlane(i, clipPlaneBuf);
             }
             clipPlaneBuf.flip();
-            GL20.glUniform4(locs[LOC_CLIP_PLANES], clipPlaneBuf);
+            RENDER_BACKEND.uniform4(locs[LOC_CLIP_PLANES], clipPlaneBuf);
         }
     }
 
     public static void onDeleteProgram(int program) {
-        programLocations.remove(program);
+        programUniforms.remove(program);
     }
 
     public static boolean hasProgram(int program) {
-        return programLocations.containsKey(program);
+        return programUniforms.containsKey(program);
     }
 
     public static int[] getLocations(int program) {
-        return programLocations.get(program);
+        final ProgramUniforms pu = programUniforms.get(program);
+        return pu == null ? null : pu.locs;
     }
 }

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

@@ -1,9 +1,8 @@
 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.VertexAttribState;
 import com.gtnewhorizons.angelica.glsm.states.ViewportState;
-import com.gtnewhorizons.angelica.loading.AngelicaTweaker;
 import org.joml.Matrix4f;
 import org.joml.Vector4f;
 import org.lwjgl.opengl.GL11;
@@ -15,6 +14,8 @@ 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
  */
@@ -39,6 +40,7 @@ public class FeedbackManager {
 
     @FunctionalInterface
     private interface IndexReader {
+
         int read(int i);
     }
 
@@ -48,7 +50,7 @@ public class FeedbackManager {
 
     public static void glFeedbackBuffer(int type, FloatBuffer buffer) {
         if (renderMode == GL11.GL_FEEDBACK) {
-            AngelicaTweaker.LOGGER.error("glFeedbackBuffer called while already in feedback mode");
+            GLStateManager.LOGGER.error("glFeedbackBuffer called while already in feedback mode");
             return;
         }
         feedbackBuffer = buffer;
@@ -65,7 +67,7 @@ public class FeedbackManager {
         };
 
         if (mode == GL11.GL_SELECT) {
-            AngelicaTweaker.LOGGER.warn("glRenderMode(GL_SELECT): selection mode not emulated");
+            GLStateManager.LOGGER.warn("glRenderMode(GL_SELECT): selection mode not emulated");
         }
 
         feedbackCount = 0;
@@ -118,20 +120,19 @@ public class FeedbackManager {
         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 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 = VertexAttribState.get(0).effectiveStride();
+        final int s = VAOManager.getAttribEffectiveStride(0);
         return (s != 0) ? s : 12;
     }
 
     private static long positionOffset() {
-        return VertexAttribState.get(0).offset;
+        return VAOManager.getAttribOffset(0);
     }
 
     public static void processDrawArrays(int mode, int first, int count) {
@@ -141,7 +142,7 @@ public class FeedbackManager {
         final int byteCount = count * stride;
         ensureReadbackCapacity(byteCount);
         readbackBuf.clear().limit(byteCount);
-        GL15.glGetBufferSubData(GL15.GL_ARRAY_BUFFER, (long) first * stride + posOffset, readbackBuf);
+        readPositionBuffer((long) first * stride + posOffset, readbackBuf);
 
         emitAllPrimitives(mode, count, i -> i, stride);
     }
@@ -150,11 +151,11 @@ public class FeedbackManager {
         computeMVP();
         final int stride = positionStride();
 
-        final int elementSize = VertexAttribState.Attrib.glTypeSizeBytes(type);
+        final int elementSize = VAOManager.Attrib.glTypeSizeBytes(type);
         final int indexByteCount = indexCount * elementSize;
         ensureIndexReadbackCapacity(indexByteCount);
         indexReadbackBuf.clear().limit(indexByteCount);
-        GL15.glGetBufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, eboOffset, indexReadbackBuf);
+        RENDER_BACKEND.getBufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, eboOffset, indexReadbackBuf);
         final ByteBuffer indexBuf = indexReadbackBuf;
 
         int minIdx = Integer.MAX_VALUE, maxIdx = Integer.MIN_VALUE;
@@ -169,7 +170,7 @@ public class FeedbackManager {
         final int byteCount = vertexCount * stride;
         ensureReadbackCapacity(byteCount);
         readbackBuf.clear().limit(byteCount);
-        GL15.glGetBufferSubData(GL15.GL_ARRAY_BUFFER, (long) minIdx * stride + posOffset, readbackBuf);
+        readPositionBuffer((long) minIdx * stride + posOffset, readbackBuf);
 
         final int base = minIdx;
         emitAllPrimitives(mode, indexCount, i -> ImmediateModeRecorder.readIndex(indexBuf, type, 0, i) - base, stride);
@@ -250,7 +251,23 @@ public class FeedbackManager {
         final int byteCount = vertexCount * stride;
         ensureReadbackCapacity(byteCount);
         readbackBuf.clear().limit(byteCount);
-        GL15.glGetBufferSubData(GL15.GL_ARRAY_BUFFER, (long) minIdx * stride + posOffset, readbackBuf);
+        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) {
@@ -344,6 +361,27 @@ public class FeedbackManager {
                 }
                 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));
         }

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

@@ -5,10 +5,7 @@
 
 package com.gtnewhorizons.angelica.glsm;
 
-import org.lwjgl.opengl.AMDDebugOutput;
-import org.lwjgl.opengl.AMDDebugOutputCallback;
-import org.lwjgl.opengl.ARBDebugOutput;
-import org.lwjgl.opengl.ARBDebugOutputCallback;
+import com.gtnewhorizons.angelica.glsm.backend.BackendManager;
 import org.lwjgl.opengl.EXTBlendColor;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL12;
@@ -16,155 +13,72 @@ import org.lwjgl.opengl.GL13;
 import org.lwjgl.opengl.GL14;
 import org.lwjgl.opengl.GL30;
 import org.lwjgl.opengl.GL43;
-import org.lwjgl.opengl.KHRDebug;
-import org.lwjgl.opengl.KHRDebugCallback;
-
-import static com.gtnewhorizons.angelica.loading.AngelicaTweaker.LOGGER;
-import static org.lwjgl.opengl.ARBDebugOutput.glDebugMessageCallbackARB;
 
 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()) {
-            LOGGER.warn("setupDebugMessageCallback called from non-main thread!");
+            GLStateManager.LOGGER.warn("setupDebugMessageCallback called from non-main thread!");
             return 0;
         }
         return setupDebugMessageCallbackImpl();
     }
 
-	public static Throwable filterStackTrace(Throwable throwable, int offset) {
-		StackTraceElement[] elems = throwable.getStackTrace();
-		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];
-		}
-		StackTraceElement[] newElems = new StackTraceElement[j];
-		System.arraycopy(filtered, 0, newElems, 0, j);
-		throwable.setStackTrace(newElems);
-		return throwable;
-	}
-
-	private static String buildStackTrace() {
-		StackTraceElement[] elems = filterStackTrace(new Throwable(), 4).getStackTrace();
-		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) {
-		String fullMessage = String.format("[GL] %s %s (0x%X) from %s: %s%s", severity, type, id, source, message, buildStackTrace());
-
-		if ("HIGH".equals(severity)) {
-			LOGGER.error(fullMessage);
-		} else if ("MEDIUM".equals(severity)) {
-			LOGGER.warn(fullMessage);
-		} else {
-			LOGGER.info(fullMessage);
-		}
-	}
-
-	private static void logDebugMessageAMD(int id, String category, String severity, String message) {
-		String fullMessage = String.format("[GL] %s %s (0x%X): %s%s", severity, category, id, message, buildStackTrace());
-
-		if ("HIGH".equals(severity)) {
-			LOGGER.error(fullMessage);
-		} else if ("MEDIUM".equals(severity)) {
-			LOGGER.warn(fullMessage);
-		} else {
-			LOGGER.info(fullMessage);
-		}
-	}
-
-    /**
-     * Sets up debug callbacks
-     * @return 0 for failure, 1 for success, 2 for restart required.
-     */
-    private static int setupDebugMessageCallbackImpl() {
-        if (GLStateManager.capabilities.OpenGL43 || GLStateManager.capabilities.GL_KHR_debug) {
-            LOGGER.info("[GL] Using OpenGL 4.3 for error logging.");
-            final KHRDebugCallback proc = new KHRDebugCallback((source, type, id, severity, message) -> {
-                logDebugMessage(id, getDebugSource(source), getDebugType(type), getDebugSeverity(severity), message);
-            });
-            GL43.glDebugMessageControl(GL11.GL_DONT_CARE, GL11.GL_DONT_CARE, GL43.GL_DEBUG_SEVERITY_HIGH, null, true);
-            GL43.glDebugMessageControl(GL11.GL_DONT_CARE, GL11.GL_DONT_CARE, GL43.GL_DEBUG_SEVERITY_MEDIUM, null, false);
-            GL43.glDebugMessageControl(GL11.GL_DONT_CARE, GL11.GL_DONT_CARE, GL43.GL_DEBUG_SEVERITY_LOW, null, false);
-            GL43.glDebugMessageControl(GL11.GL_DONT_CARE, GL11.GL_DONT_CARE, GL43.GL_DEBUG_SEVERITY_NOTIFICATION, null, false);
-            GL43.glDebugMessageCallback(proc);
-
-            // Enable synchronous debug output so errors are reported immediately with accurate stack traces
-            GL11.glEnable(GL43.GL_DEBUG_OUTPUT_SYNCHRONOUS);
-
-            if ((GL11.glGetInteger(GL30.GL_CONTEXT_FLAGS) & GL43.GL_CONTEXT_FLAG_DEBUG_BIT) == 0) {
-                LOGGER.warn("[GL] Warning: A non-debug context may not produce any debug output.");
-                GL11.glEnable(GL43.GL_DEBUG_OUTPUT);
-                return 2;
+    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 = "";
             }
-            return 1;
-        } else if (GLStateManager.capabilities.GL_ARB_debug_output) {
-            LOGGER.info("[GL] Using ARB_debug_output for error logging.");
-            final ARBDebugOutputCallback proc = new ARBDebugOutputCallback((source, type, id, severity, message) -> {
-                logDebugMessage(id, getSourceARB(source), getTypeARB(type), getSeverityARB(severity), message);
-            });
-            ARBDebugOutput.glDebugMessageControlARB(GL11.GL_DONT_CARE, GL11.GL_DONT_CARE, GL43.GL_DEBUG_SEVERITY_HIGH, null, true);
-            ARBDebugOutput.glDebugMessageControlARB(GL11.GL_DONT_CARE, GL11.GL_DONT_CARE, GL43.GL_DEBUG_SEVERITY_MEDIUM, null, false);
-            ARBDebugOutput.glDebugMessageControlARB(GL11.GL_DONT_CARE, GL11.GL_DONT_CARE, GL43.GL_DEBUG_SEVERITY_LOW, null, false);
-            ARBDebugOutput.glDebugMessageControlARB(GL11.GL_DONT_CARE, GL11.GL_DONT_CARE, GL43.GL_DEBUG_SEVERITY_NOTIFICATION, null, false);
-            ARBDebugOutput.glDebugMessageCallbackARB(proc);
+            filtered[j++] = elems[i];
+        }
+        final StackTraceElement[] newElems = new StackTraceElement[j];
+        System.arraycopy(filtered, 0, newElems, 0, j);
+        throwable.setStackTrace(newElems);
+        return throwable;
+    }
 
-            // Enable synchronous debug output so errors are reported immediately with accurate stack traces
-            GL11.glEnable(ARBDebugOutput.GL_DEBUG_OUTPUT_SYNCHRONOUS_ARB);
-            return 1;
-        } else if (GLStateManager.capabilities.GL_AMD_debug_output) {
-            LOGGER.info("[GL] Using AMD_debug_output for error logging.");
-            final AMDDebugOutputCallback proc = new AMDDebugOutputCallback((id, category, severity, message) -> {
-                logDebugMessageAMD(id, getCategoryAMD(category), getSeverityAMD(severity), message);
-            });
-            AMDDebugOutput.glDebugMessageEnableAMD(0, GL43.GL_DEBUG_SEVERITY_HIGH, null, true);
-            AMDDebugOutput.glDebugMessageEnableAMD(0, GL43.GL_DEBUG_SEVERITY_MEDIUM, null, false);
-            AMDDebugOutput.glDebugMessageEnableAMD(0, GL43.GL_DEBUG_SEVERITY_LOW, null, false);
-            AMDDebugOutput.glDebugMessageEnableAMD(0, GL43.GL_DEBUG_SEVERITY_NOTIFICATION, null, false);
-            AMDDebugOutput.glDebugMessageCallbackAMD(proc);
-            return 1;
+    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 {
-            LOGGER.info("[GL] No debug output implementation is available, cannot return debug info.");
-            return 0;
+            GLStateManager.LOGGER.info(fullMessage);
         }
     }
 
-	public static int disableDebugMessages() {
-		if (GLStateManager.capabilities.OpenGL43) {
-			GL43.glDebugMessageCallback(null);
-			return 1;
-		} else if (GLStateManager.capabilities.GL_KHR_debug) {
-			KHRDebug.glDebugMessageCallback(null);
-			if (GLStateManager.capabilities.OpenGL30 && (GL11.glGetInteger(GL30.GL_CONTEXT_FLAGS) & 2) == 0) {
-                GL11.glDisable(GL43.GL_DEBUG_OUTPUT);
-			}
-			return 1;
-		} else if (GLStateManager.capabilities.GL_ARB_debug_output) {
-			glDebugMessageCallbackARB(null);
-			return 1;
-		} else if (GLStateManager.capabilities.GL_AMD_debug_output) {
-			AMDDebugOutput.glDebugMessageCallbackAMD(null);
-			return 1;
-		} else {
-			LOGGER.info("[GL] No debug output implementation is available, cannot disable debug info.");
-			return 0;
-		}
-	}
+    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) {
+    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";
@@ -174,9 +88,9 @@ public final class GLDebug {
             case GL43.GL_DEBUG_SOURCE_OTHER -> "OTHER";
             default -> String.format("Unknown [0x%X]", source);
         };
-	}
+    }
 
-	private static String getDebugType(int type) {
+    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";
@@ -187,9 +101,9 @@ public final class GLDebug {
             case GL43.GL_DEBUG_TYPE_MARKER -> "MARKER";
             default -> String.format("Unknown [0x%X]", type);
         };
-	}
+    }
 
-	private static String getDebugSeverity(int severity) {
+    private static String getDebugSeverity(int severity) {
         return switch (severity) {
             case GL43.GL_DEBUG_SEVERITY_NOTIFICATION -> "NOTIFICATION";
             case GL43.GL_DEBUG_SEVERITY_HIGH -> "HIGH";
@@ -197,65 +111,9 @@ public final class GLDebug {
             case GL43.GL_DEBUG_SEVERITY_LOW -> "LOW";
             default -> String.format("Unknown [0x%X]", severity);
         };
-	}
-
-    private static String getSourceARB(int source) {
-        return switch (source) {
-            case ARBDebugOutput.GL_DEBUG_SOURCE_API_ARB -> "API";
-            case ARBDebugOutput.GL_DEBUG_SOURCE_WINDOW_SYSTEM_ARB -> "WINDOW SYSTEM";
-            case ARBDebugOutput.GL_DEBUG_SOURCE_SHADER_COMPILER_ARB -> "SHADER COMPILER";
-            case ARBDebugOutput.GL_DEBUG_SOURCE_THIRD_PARTY_ARB -> "THIRD PARTY";
-            case ARBDebugOutput.GL_DEBUG_SOURCE_APPLICATION_ARB -> "APPLICATION";
-            case ARBDebugOutput.GL_DEBUG_SOURCE_OTHER_ARB -> "OTHER";
-            default -> String.format("Unknown [0x%X]", source);
-        };
     }
 
-    private static String getTypeARB(int type) {
-        return switch (type) {
-            case ARBDebugOutput.GL_DEBUG_TYPE_ERROR_ARB -> "ERROR";
-            case ARBDebugOutput.GL_DEBUG_TYPE_DEPRECATED_BEHAVIOR_ARB -> "DEPRECATED BEHAVIOR";
-            case ARBDebugOutput.GL_DEBUG_TYPE_UNDEFINED_BEHAVIOR_ARB -> "UNDEFINED BEHAVIOR";
-            case ARBDebugOutput.GL_DEBUG_TYPE_PORTABILITY_ARB -> "PORTABILITY";
-            case ARBDebugOutput.GL_DEBUG_TYPE_PERFORMANCE_ARB -> "PERFORMANCE";
-            case ARBDebugOutput.GL_DEBUG_TYPE_OTHER_ARB -> "OTHER";
-            default -> String.format("Unknown [0x%X]", type);
-        };
-    }
-
-    private static String getSeverityARB(int severity) {
-        return switch (severity) {
-            case ARBDebugOutput.GL_DEBUG_SEVERITY_HIGH_ARB -> "HIGH";
-            case ARBDebugOutput.GL_DEBUG_SEVERITY_MEDIUM_ARB -> "MEDIUM";
-            case ARBDebugOutput.GL_DEBUG_SEVERITY_LOW_ARB -> "LOW";
-            default -> String.format("Unknown [0x%X]", severity);
-        };
-    }
-
-	private static String getCategoryAMD(int category) {
-        return switch (category) {
-            case AMDDebugOutput.GL_DEBUG_CATEGORY_API_ERROR_AMD -> "API ERROR";
-            case AMDDebugOutput.GL_DEBUG_CATEGORY_WINDOW_SYSTEM_AMD -> "WINDOW SYSTEM";
-            case AMDDebugOutput.GL_DEBUG_CATEGORY_DEPRECATION_AMD -> "DEPRECATION";
-            case AMDDebugOutput.GL_DEBUG_CATEGORY_UNDEFINED_BEHAVIOR_AMD -> "UNDEFINED BEHAVIOR";
-            case AMDDebugOutput.GL_DEBUG_CATEGORY_PERFORMANCE_AMD -> "PERFORMANCE";
-            case AMDDebugOutput.GL_DEBUG_CATEGORY_SHADER_COMPILER_AMD -> "SHADER COMPILER";
-            case AMDDebugOutput.GL_DEBUG_CATEGORY_APPLICATION_AMD -> "APPLICATION";
-            case AMDDebugOutput.GL_DEBUG_CATEGORY_OTHER_AMD -> "OTHER";
-            default -> String.format("Unknown [0x%X]", category);
-        };
-	}
-
-	private static String getSeverityAMD(int severity) {
-        return switch (severity) {
-            case AMDDebugOutput.GL_DEBUG_SEVERITY_HIGH_AMD -> "HIGH";
-            case AMDDebugOutput.GL_DEBUG_SEVERITY_MEDIUM_AMD -> "MEDIUM";
-            case AMDDebugOutput.GL_DEBUG_SEVERITY_LOW_AMD -> "LOW";
-            default -> String.format("Unknown [0x%X]", severity);
-        };
-	}
-
-	public static String getMatrixModeName(int mode) {
+    public static String getMatrixModeName(int mode) {
         return switch (mode) {
             case GL11.GL_MODELVIEW -> "MODELVIEW";
             case GL11.GL_PROJECTION -> "PROJECTION";
@@ -263,9 +121,9 @@ public final class GLDebug {
             case GL11.GL_COLOR -> "COLOR";
             default -> String.format("0x%X", mode);
         };
-	}
+    }
 
-	public static String getCapabilityName(int cap) {
+    public static String getCapabilityName(int cap) {
         return switch (cap) {
             case GL11.GL_ALPHA_TEST -> "ALPHA_TEST";
             case GL11.GL_BLEND -> "BLEND";
@@ -295,9 +153,9 @@ public final class GLDebug {
             case GL11.GL_LIGHT7 -> "LIGHT7";
             default -> String.format("0x%X", cap);
         };
-	}
+    }
 
-	public static String getComparisonFuncName(int func) {
+    public static String getComparisonFuncName(int func) {
         return switch (func) {
             case GL11.GL_NEVER -> "NEVER";
             case GL11.GL_LESS -> "LESS";
@@ -309,9 +167,9 @@ public final class GLDebug {
             case GL11.GL_ALWAYS -> "ALWAYS";
             default -> String.format("0x%X", func);
         };
-	}
+    }
 
-	public static String getBlendFactorName(int factor) {
+    public static String getBlendFactorName(int factor) {
         return switch (factor) {
             case GL11.GL_ZERO -> "ZERO";
             case GL11.GL_ONE -> "ONE";
@@ -330,17 +188,17 @@ public final class GLDebug {
             case GL11.GL_SRC_ALPHA_SATURATE -> "SRC_ALPHA_SATURATE";
             default -> String.format("0x%X", factor);
         };
-	}
+    }
 
-	public static String getShadeModelName(int mode) {
+    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) {
+    public static String getTextureTargetName(int target) {
         return switch (target) {
             case GL11.GL_TEXTURE_1D -> "TEXTURE_1D";
             case GL11.GL_TEXTURE_2D -> "TEXTURE_2D";
@@ -348,9 +206,9 @@ public final class GLDebug {
             case GL13.GL_TEXTURE_CUBE_MAP -> "TEXTURE_CUBE_MAP";
             default -> String.format("0x%X", target);
         };
-	}
+    }
 
-	public static String getTexturePnameName(int pname) {
+    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";
@@ -367,9 +225,9 @@ public final class GLDebug {
             case GL14.GL_GENERATE_MIPMAP -> "GENERATE_MIPMAP";
             default -> String.format("0x%X", pname);
         };
-	}
+    }
 
-	public static String getTextureFormatName(int format) {
+    public static String getTextureFormatName(int format) {
         return switch (format) {
             case GL11.GL_RED -> "RED";
             case GL11.GL_GREEN -> "GREEN";
@@ -392,9 +250,9 @@ public final class GLDebug {
             case GL11.GL_LUMINANCE8_ALPHA8 -> "LUMINANCE8_ALPHA8";
             default -> String.format("0x%X", format);
         };
-	}
+    }
 
-	public static String getDataTypeName(int type) {
+    public static String getDataTypeName(int type) {
         return switch (type) {
             case GL11.GL_UNSIGNED_BYTE -> "UNSIGNED_BYTE";
             case GL11.GL_BYTE -> "BYTE";
@@ -411,9 +269,9 @@ public final class GLDebug {
             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) {
+    public static String getLightName(int light) {
         return switch (light) {
             case GL11.GL_LIGHT0 -> "LIGHT0";
             case GL11.GL_LIGHT1 -> "LIGHT1";
@@ -425,9 +283,9 @@ public final class GLDebug {
             case GL11.GL_LIGHT7 -> "LIGHT7";
             default -> String.format("0x%X", light);
         };
-	}
+    }
 
-	public static String getLightPnameName(int pname) {
+    public static String getLightPnameName(int pname) {
         return switch (pname) {
             case GL11.GL_AMBIENT -> "AMBIENT";
             case GL11.GL_DIFFUSE -> "DIFFUSE";
@@ -441,9 +299,9 @@ public final class GLDebug {
             case GL11.GL_QUADRATIC_ATTENUATION -> "QUADRATIC_ATTENUATION";
             default -> String.format("0x%X", pname);
         };
-	}
+    }
 
-	public static String getMaterialPnameName(int pname) {
+    public static String getMaterialPnameName(int pname) {
         return switch (pname) {
             case GL11.GL_AMBIENT -> "AMBIENT";
             case GL11.GL_DIFFUSE -> "DIFFUSE";
@@ -454,18 +312,18 @@ public final class GLDebug {
             case GL11.GL_COLOR_INDEXES -> "COLOR_INDEXES";
             default -> String.format("0x%X", pname);
         };
-	}
+    }
 
-	public static String getFaceName(int face) {
+    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) {
+    public static String getColorMaterialModeName(int mode) {
         return switch (mode) {
             case GL11.GL_AMBIENT -> "AMBIENT";
             case GL11.GL_DIFFUSE -> "DIFFUSE";
@@ -474,9 +332,9 @@ public final class GLDebug {
             case GL11.GL_AMBIENT_AND_DIFFUSE -> "AMBIENT_AND_DIFFUSE";
             default -> String.format("0x%X", mode);
         };
-	}
+    }
 
-	public static String getFogPnameName(int pname) {
+    public static String getFogPnameName(int pname) {
         return switch (pname) {
             case GL11.GL_FOG_MODE -> "FOG_MODE";
             case GL11.GL_FOG_DENSITY -> "FOG_DENSITY";
@@ -486,9 +344,9 @@ public final class GLDebug {
             case GL11.GL_FOG_COLOR -> "FOG_COLOR";
             default -> String.format("0x%X", pname);
         };
-	}
+    }
 
-	public static String getLightModelPnameName(int 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";
@@ -496,9 +354,9 @@ public final class GLDebug {
             case GL12.GL_LIGHT_MODEL_COLOR_CONTROL -> "LIGHT_MODEL_COLOR_CONTROL";
             default -> String.format("0x%X", pname);
         };
-	}
+    }
 
-	public static String getClearMaskString(int mask) {
+    public static String getClearMaskString(int mask) {
         StringBuilder sb = new StringBuilder();
         boolean first = true;
         if ((mask & GL11.GL_COLOR_BUFFER_BIT) != 0) {
@@ -520,18 +378,18 @@ public final class GLDebug {
             sb.append("ACCUM");
         }
         return sb.toString();
-	}
+    }
 
-	public static String getCullFaceName(int mode) {
+    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) {
+    public static String getLogicOpName(int opcode) {
         return switch (opcode) {
             case GL11.GL_CLEAR -> "CLEAR";
             case GL11.GL_AND -> "AND";
@@ -551,9 +409,9 @@ public final class GLDebug {
             case GL11.GL_SET -> "SET";
             default -> String.format("0x%X", opcode);
         };
-	}
+    }
 
-	public static String getFramebufferStatusName(int status) {
+    public static String getFramebufferStatusName(int status) {
         return switch (status) {
             case GL30.GL_FRAMEBUFFER_COMPLETE -> "COMPLETE";
             case GL30.GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT -> "INCOMPLETE_ATTACHMENT";
@@ -565,9 +423,9 @@ public final class GLDebug {
             case 0 -> "NO_FRAMEBUFFER_BOUND";
             default -> String.format("UNKNOWN(0x%X)", status);
         };
-	}
+    }
 
-	public static String getInternalFormatName(int format) {
+    public static String getInternalFormatName(int format) {
         return switch (format) {
             // Basic
             case GL11.GL_RGBA -> "RGBA";
@@ -602,33 +460,37 @@ public final class GLDebug {
             case GL11.GL_RGB10_A2 -> "RGB10_A2";
             default -> String.format("0x%X", format);
         };
-	}
+    }
 
-	private static DebugState debugState;
+    private static DebugState debugState;
 
     private interface DebugState {
-		void nameObject(int id, int object, String name);
-		void pushGroup(String name);
-		void popGroup();
+
+        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 class KHRDebugState implements DebugState {
+
         private static final int ID = 0;
-		private int depth = 0;
-        private static final int maxDepth = GL11.glGetInteger(KHRDebug.GL_MAX_DEBUG_GROUP_STACK_DEPTH);
-        private static final int maxNameLength = GL11.glGetInteger(KHRDebug.GL_MAX_LABEL_LENGTH);
+        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) {
-			KHRDebug.glObjectLabel(id, object, name);
-		}
+        @Override
+        public void nameObject(int id, int object, String name) {
+            BackendManager.RENDER_BACKEND.objectLabel(id, object, name);
+        }
 
-		@Override
-		public void pushGroup(String 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");
@@ -639,46 +501,51 @@ public final class GLDebug {
                 throw new RuntimeException(sb.toString());
             }
             groupStack[depth] = name;
-			KHRDebug.glPushDebugGroup(KHRDebug.GL_DEBUG_SOURCE_APPLICATION, ID, name);
+            BackendManager.RENDER_BACKEND.pushDebugGroup(GL43.GL_DEBUG_SOURCE_APPLICATION, ID, name);
             depth++;
-		}
+        }
 
-		@Override
-		public void popGroup() {
+        @Override
+        public void popGroup() {
             if (depth - 1 < 0) {
                 throw new RuntimeException("Stack underflow");
             }
-            KHRDebug.glPopDebugGroup();
+            BackendManager.RENDER_BACKEND.popDebugGroup();
             depth--;
             groupStack[depth] = null;
-		}
+        }
 
         @Override
         public void debugMessage(String message) {
-            KHRDebug.glDebugMessageInsert(KHRDebug.GL_DEBUG_SOURCE_APPLICATION, KHRDebug.GL_DEBUG_TYPE_MARKER, ID, KHRDebug.GL_DEBUG_SEVERITY_NOTIFICATION, 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 "";
+            if (program == 0) return "";
 
-            return KHRDebug.glGetObjectLabel(glProgram, program, maxNameLength);
+            return BackendManager.RENDER_BACKEND.getObjectLabel(glProgram, program);
         }
     }
 
-	private static class UnsupportedDebugState implements DebugState {
-		@Override
-		public void nameObject(int id, int object, String name) {
-		}
+    private static class UnsupportedDebugState implements DebugState {
 
-		@Override
-		public void pushGroup(String name) {
-		}
+        @Override
+        public void nameObject(int id, int object, String name) {
+        }
 
-		@Override
-		public void popGroup() {
-		}
+        @Override
+        public void pushGroup(String name) {
+        }
+
+        @Override
+        public void popGroup() {
+        }
 
         @Override
         public void debugMessage(String name) {
@@ -691,40 +558,43 @@ public final class GLDebug {
         }
     }
 
-	public static void initDebugState() {
-		if (GLStateManager.capabilities.GL_KHR_debug || GLStateManager.capabilities.OpenGL43) {
-			debugState = new KHRDebugState();
-		} else {
-			debugState = new UnsupportedDebugState();
-		}
-	}
+    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()) {
+        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()) {
+        if (debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
             debugState.pushGroup(group);
         }
     }
+
     public static void popGroup() {
-        if(debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
+        if (debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
             debugState.popGroup();
         }
     }
+
     public static void debugMessage(String message) {
-        if(debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
+        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()) {
+        if (debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
             return debugState.getObjectLabel(glProgram, program);
         }
         return "";
     }
 
-
 }

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

@@ -36,7 +36,14 @@ public class GlslTransformUtils {
     /** 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(
-        400, List.of(new ReservedWordRename(Pattern.compile("\\bsample\\b"), RENAMED_PREFIX + "sample"))
+        // 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) {
@@ -55,7 +62,8 @@ public class GlslTransformUtils {
 
     public static String renameReservedWords(String source, int targetVersion) {
         for (var entry : VERSIONED_RESERVED_WORDS.entrySet()) {
-            if (targetVersion < entry.getKey()) {
+            // 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());
                 }
@@ -66,6 +74,7 @@ public class GlslTransformUtils {
 
     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;
     }

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

@@ -0,0 +1,380 @@
+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) {
+        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);
+    }
+
+    /**
+     * 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) {
+        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);
+        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 +1,564 @@
+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();
+            }
+        }
+
+        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) {
+        RENDER_BACKEND.bufferData(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 RENDER_BACKEND.genBuffers();
+    }
+
+    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) {
+        RENDER_BACKEND.bufferStorage(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);
+        RENDER_BACKEND.clearBufferSubData(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". Inlined from StandardMacros.getGlVersion(). */
+    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;
+    }
+}

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 +1,342 @@
+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 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 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, 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/lwjgl/AngelicaPartialDisk.java

@@ -3,7 +3,6 @@ package com.gtnewhorizons.angelica.glsm.compat.lwjgl;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import org.lwjgl.util.glu.PartialDisk;
 
-import static com.gtnewhorizons.angelica.loading.AngelicaTweaker.LOGGER;
 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;
@@ -35,7 +34,7 @@ public class AngelicaPartialDisk extends PartialDisk {
 
         if (slices >= CACHE_SIZE) slices = CACHE_SIZE - 1;
         if (slices < 2 || loops < 1 || outerRadius <= 0.0f || innerRadius < 0.0f || innerRadius > outerRadius) {
-            LOGGER.warn("PartialDisk: GLU_INVALID_VALUE (slices={}, loops={}, innerRadius={}, outerRadius={})", slices, loops, innerRadius, outerRadius);
+            GLStateManager.LOGGER.warn("PartialDisk: GLU_INVALID_VALUE (slices={}, loops={}, innerRadius={}, outerRadius={})", slices, loops, innerRadius, outerRadius);
             return;
         }
 

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

@@ -1,18 +1,18 @@
 package com.gtnewhorizons.angelica.glsm.dsa;
 
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
-import org.lwjgl.opengl.ARBDirectStateAccess;
-import org.lwjgl.opengl.GL45;
 
 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) {
-        ARBDirectStateAccess.glGenerateTextureMipmap(texture);
+        RENDER_BACKEND.generateTextureMipmap(texture);
     }
 
     @Override
@@ -30,12 +30,12 @@ public class DSAARB extends DSAUnsupported {
 
     @Override
     public void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, ByteBuffer pixels) {
-        ARBDirectStateAccess.glTextureSubImage2D(texture, level, xoffset, yoffset, width, height, format, type, 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) {
-        ARBDirectStateAccess.glTextureSubImage2D(texture, level, xoffset, yoffset, width, height, format, type, pixels);
+        RENDER_BACKEND.textureSubImage2D(texture, level, xoffset, yoffset, width, height, format, type, pixels);
     }
 
     @Override
@@ -43,7 +43,7 @@ public class DSAARB extends DSAUnsupported {
         param = GLStateManager.remapTexClamp(pname, param);
         if(!GLStateManager.updateTexParameteriCache(target, texture, pname, param)) return;
 
-        ARBDirectStateAccess.glTextureParameteri(texture, pname, param);
+        RENDER_BACKEND.textureParameteri(texture, target, pname, param);
     }
 
     @Override
@@ -51,38 +51,38 @@ public class DSAARB extends DSAUnsupported {
         param = GLStateManager.remapTexClamp(pname, param);
         if(!GLStateManager.updateTexParameterfCache(target, texture, pname, param)) return;
 
-        ARBDirectStateAccess.glTextureParameterf(texture, pname, param);
+        RENDER_BACKEND.textureParameterf(texture, target, pname, param);
     }
 
     @Override
     public void texParameteriv(int texture, int target, int pname, IntBuffer params) {
         GLStateManager.remapTexClampBuffer(pname, params);
-        ARBDirectStateAccess.glTextureParameter(texture, pname, params);
+        RENDER_BACKEND.textureParameteriv(texture, target, pname, params);
     }
 
     @Override
     public void readBuffer(int framebuffer, int buffer) {
-        ARBDirectStateAccess.glNamedFramebufferReadBuffer(framebuffer, buffer);
+        RENDER_BACKEND.namedFramebufferReadBuffer(framebuffer, buffer);
     }
 
     @Override
     public void drawBuffers(int framebuffer, IntBuffer buffers) {
-        ARBDirectStateAccess.glNamedFramebufferDrawBuffers(framebuffer, buffers);
+        RENDER_BACKEND.namedFramebufferDrawBuffers(framebuffer, buffers);
     }
 
     @Override
     public int getTexParameteri(int texture, int target, int pname) {
-        return GLStateManager.getTexParameterOrDefault(texture, pname, () -> ARBDirectStateAccess.glGetTextureParameteri(texture, pname));
+        return GLStateManager.getTexParameterOrDefault(texture, pname, () -> RENDER_BACKEND.getTextureParameteri(texture, target, pname));
     }
 
     @Override
     public int getTexLevelParameteri(int texture, int level, int pname) {
-        return ARBDirectStateAccess.glGetTextureLevelParameteri(texture, level, 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) {
-        ARBDirectStateAccess.glCopyTextureSubImage2D(destTexture, i, i1, i2, i3, i4, width, height);
+        RENDER_BACKEND.copyTextureSubImage2D(destTexture, target, i, i1, i2, i3, i4, width, height);
     }
 
     @Override
@@ -92,7 +92,7 @@ public class DSAARB extends DSAUnsupported {
         if (texture == 0) {
             super.bindTextureToUnit(unit, texture);
         } else {
-            ARBDirectStateAccess.glBindTextureUnit(unit, texture);
+            RENDER_BACKEND.bindTextureUnit(unit, texture);
             GLStateManager.getTextures().getTextureUnitBindings(unit).setBinding(texture);
         }
     }
@@ -104,44 +104,44 @@ public class DSAARB extends DSAUnsupported {
 
     @Override
     public int bufferStorage(int target, FloatBuffer data, int usage) {
-        final int buffer = GL45.glCreateBuffers();
-        GL45.glNamedBufferData(buffer, data, usage);
+        final int buffer = RENDER_BACKEND.createBuffers();
+        RENDER_BACKEND.namedBufferData(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) {
-        ARBDirectStateAccess.glBlitNamedFramebuffer(source, dest, offsetX, offsetY, width, height, offsetX2, offsetY2, width2, height2, bufferChoice, 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) {
-        ARBDirectStateAccess.glNamedFramebufferTexture(fb, attachment, texture, levels);
+        RENDER_BACKEND.namedFramebufferTexture(fb, attachment, texture, levels);
     }
 
     @Override
     public int createFramebuffer() {
-        return ARBDirectStateAccess.glCreateFramebuffers();
+        return RENDER_BACKEND.createFramebuffers();
     }
 
     @Override
     public int createTexture(int target) {
-        return ARBDirectStateAccess.glCreateTextures(target);
+        return RENDER_BACKEND.createTextures(target);
     }
 
     @Override
     public void textureStorage1D(int texture, int target, int levels, int internalFormat, int width) {
-        ARBDirectStateAccess.glTextureStorage1D(texture, levels, internalFormat, width);
+        RENDER_BACKEND.textureStorage1D(texture, levels, internalFormat, width);
     }
 
     @Override
     public void textureStorage2D(int texture, int target, int levels, int internalFormat, int width, int height) {
-        ARBDirectStateAccess.glTextureStorage2D(texture, levels, internalFormat, width, 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) {
-        ARBDirectStateAccess.glTextureStorage3D(texture, levels, internalFormat, width, height, depth);
+        RENDER_BACKEND.textureStorage3D(texture, levels, internalFormat, width, height, depth);
     }
 }

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

@@ -1,18 +1,18 @@
 package com.gtnewhorizons.angelica.glsm.dsa;
 
-import org.lwjgl.opengl.EXTDirectStateAccess;
-
 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) {
-        EXTDirectStateAccess.glTextureImage2DEXT(texture, target, level, internalformat, width, height, border, format, type, 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) {
-        EXTDirectStateAccess.glTextureImage2DEXT(texture, target, level, internalformat, width, height, border, format, type, 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

@@ -1,15 +1,13 @@
 package com.gtnewhorizons.angelica.glsm.dsa;
 
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
-import com.gtnewhorizons.angelica.glsm.RenderSystem;
 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.GL15;
-import org.lwjgl.opengl.GL20;
 import org.lwjgl.opengl.GL30;
 import org.lwjgl.opengl.GL31;
-import org.lwjgl.opengl.GL42;
 
 import java.nio.ByteBuffer;
 import java.nio.FloatBuffer;
@@ -20,40 +18,40 @@ public class DSAUnsupported implements DSAAccess {
     @Override
     public void generateMipmaps(int texture, int target) {
         GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
-        GL30.glGenerateMipmap(target);
+        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();
-        GL11.glBindTexture(target, texture);
-        GL11.glTexImage2D(target, level, internalformat, width, height, border, format, type, pixels);
-        GL11.glBindTexture(target, cachedBinding); // Restore to cache value
+        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();
-        GL11.glBindTexture(target, texture);
-        GL11.glTexImage2D(target, level, internalformat, width, height, border, format, type, pixels);
-        GL11.glBindTexture(target, cachedBinding);
+        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();
-        GL11.glBindTexture(target, texture);
-        GL11.glTexSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);
-        GL11.glBindTexture(target, cachedBinding);
+        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();
-        GL11.glBindTexture(target, texture);
-        GL11.glTexSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);
-        GL11.glBindTexture(target, cachedBinding);
+        RENDER_BACKEND.bindTexture(target, texture);
+        RENDER_BACKEND.texSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);
+        RENDER_BACKEND.bindTexture(target, cachedBinding);
     }
 
     @Override
@@ -77,13 +75,13 @@ public class DSAUnsupported implements DSAAccess {
     @Override
     public void readBuffer(int framebuffer, int buffer) {
         GLStateManager.glBindFramebuffer(GL30.GL_FRAMEBUFFER, framebuffer);
-        GL11.glReadBuffer(buffer);
+        RENDER_BACKEND.readBuffer(buffer);
     }
 
     @Override
     public void drawBuffers(int framebuffer, IntBuffer buffers) {
         GLStateManager.glBindFramebuffer(GL30.GL_FRAMEBUFFER, framebuffer);
-        GL20.glDrawBuffers(buffers);
+        RENDER_BACKEND.drawBuffers(buffers);
     }
 
     @Override
@@ -95,9 +93,9 @@ public class DSAUnsupported implements DSAAccess {
     @Override
     public int getTexLevelParameteri(int texture, int level, int pname) {
         final int previous = GLStateManager.getBoundTextureForServerState();
-        GL11.glBindTexture(GL11.GL_TEXTURE_2D, texture);
-        final int result = GL11.glGetTexLevelParameteri(GL11.GL_TEXTURE_2D, level, pname);
-        GL11.glBindTexture(GL11.GL_TEXTURE_2D, previous);
+        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;
     }
 
@@ -105,7 +103,7 @@ public class DSAUnsupported implements DSAAccess {
     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);
-        GL11.glCopyTexSubImage2D(target, i, i1, i2, i3, i4, width, height);
+        RENDER_BACKEND.copyTexSubImage2D(target, i, i1, i2, i3, i4, width, height);
         GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, previous);
     }
 
@@ -123,9 +121,9 @@ public class DSAUnsupported implements DSAAccess {
 
     @Override
     public int bufferStorage(int target, FloatBuffer data, int usage) {
-        final int buffer = GL15.glGenBuffers();
+        final int buffer = RENDER_BACKEND.genBuffers();
         GLStateManager.glBindBuffer(target, buffer);
-        RenderSystem.bufferData(target, data, usage);
+        RENDER_BACKEND.bufferData(target, data, usage);
         GLStateManager.glBindBuffer(target, 0);
 
         return buffer;
@@ -136,13 +134,13 @@ public class DSAUnsupported implements DSAAccess {
         int bufferChoice, int filter) {
         GLStateManager.glBindFramebuffer(GL30.GL_READ_FRAMEBUFFER, source);
         GLStateManager.glBindFramebuffer(GL30.GL_DRAW_FRAMEBUFFER, dest);
-        GL30.glBlitFramebuffer(offsetX, offsetY, width, height, offsetX2, offsetY2, width2, height2, bufferChoice, filter);
+        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);
-        GL30.glFramebufferTexture2D(fbtarget, attachment, target, texture, levels);
+        RENDER_BACKEND.framebufferTexture2D(fbtarget, attachment, target, texture, levels);
     }
 
     @Override
@@ -154,32 +152,32 @@ public class DSAUnsupported implements DSAAccess {
 
     @Override
     public int createTexture(int target) {
-        final int texture = GL11.glGenTextures();
+        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 = GL11.glGetInteger(GL11.GL_TEXTURE_BINDING_1D);
-        GL11.glBindTexture(target, texture);
-        GL42.glTexStorage1D(target, levels, internalFormat, width);
-        GL11.glBindTexture(target, previous);
+        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() : GL11.glGetInteger(GL31.GL_TEXTURE_BINDING_RECTANGLE);
-        GL11.glBindTexture(target, texture);
-        GL42.glTexStorage2D(target, levels, internalFormat, width, height);
-        GL11.glBindTexture(target, previous);
+        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 = GL11.glGetInteger(GL12.GL_TEXTURE_BINDING_3D);
-        GL11.glBindTexture(target, texture);
-        GL42.glTexStorage3D(target, levels, internalFormat, width, height, depth);
-        GL11.glBindTexture(target, previous);
+        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

@@ -4,8 +4,6 @@ import java.util.Arrays;
 
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.TexEnvState;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL12;
 import org.lwjgl.opengl.GL13;
@@ -14,7 +12,7 @@ import org.lwjgl.opengl.GL13;
  * Packed-long fragment shader permutation key for FFP emulation.
  *
  * Layout:
- *   long[0]: global bits (10) + unit 0 (47 bits at offset 10)
+ *   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.
  *
@@ -34,8 +32,6 @@ import org.lwjgl.opengl.GL13;
  *   42-46: arg2 Alpha
  */
 public final class FragmentKey {
-    private static final Logger LOGGER = LogManager.getLogger("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;
@@ -67,12 +63,13 @@ public final class FragmentKey {
     public static final int FOG_EXP    = 2;
     public static final int FOG_EXP2   = 3;
 
-    private static final int GLOBAL_BITS = 10;
+    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
@@ -123,6 +120,11 @@ public final class FragmentKey {
             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) {
@@ -133,7 +135,8 @@ public final class FragmentKey {
         int highestEnabled = -1;
         long unit0Bits = 0;
         for (int i = 0; i < MAX_UNITS; i++) {
-            final boolean texEnabled = GLStateManager.getTextures().getTextureUnitStates(i).isEnabled();
+            // 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);
@@ -231,6 +234,7 @@ public final class FragmentKey {
     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];
@@ -256,6 +260,28 @@ public final class FragmentKey {
         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);
     }
@@ -297,7 +323,7 @@ public final class FragmentKey {
             case GL13.GL_PRIMARY_COLOR -> SRC_PRIMARY_COLOR;
             case GL13.GL_PREVIOUS      -> SRC_PREVIOUS;
             default -> {
-                LOGGER.debug("Unknown TexEnv source 0x{}, falling back to SRC_PREVIOUS", Integer.toHexString(glSource));
+                GLStateManager.LOGGER.debug("Unknown TexEnv source 0x{}, falling back to SRC_PREVIOUS", Integer.toHexString(glSource));
                 yield SRC_PREVIOUS;
             }
         };
@@ -342,10 +368,10 @@ public final class FragmentKey {
             default -> "?";
         };
         final StringBuilder sb = new StringBuilder();
-        sb.append(String.format("FFPFragmentKey[fog=%s alpha=%b(%s) specSep=%b units=%d",
+        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(), nrEnabledUnits()));
+            separateSpecular(), overlayEnabled(), nrEnabledUnits()));
         for (int i = 0; i < nrEnabledUnits(); i++) {
             if (!unitEnabled(i)) {
                 sb.append(String.format(" u%d=OFF", i));

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

@@ -37,11 +37,11 @@ public final class FragmentShaderGenerator {
         if (key.separateSpecular()) {
             sb.append("in vec3 v_SpecularColor;\n");
         }
-        if (key.textureEnabled()) {
-            sb.append("in vec4 v_TexCoord0;\n");
-        }
-        if (key.lightmapEnabled()) {
-            sb.append("in vec4 v_TexCoord1;\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");
@@ -65,6 +65,9 @@ public final class FragmentShaderGenerator {
                 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");
@@ -75,26 +78,29 @@ public final class FragmentShaderGenerator {
     private static void emitTextureSampling(StringBuilder sb, FragmentKey key) {
         for (int i = 0; i < key.nrEnabledUnits(); i++) {
             if (!key.unitEnabled(i)) continue;
-            // Unit 1 is the lightmap — uses v_TexCoord1.
-            // Units 2-3 intentionally share unit 0's texture coordinates since
-            // the vertex shader only provides 2 tex coord varyings (unit 0 and unit 1/lightmap).
-            final String texCoord = (i == 1) ? "v_TexCoord1.st" : "v_TexCoord0.st";
-            sb.append("  vec4 tex").append(i).append("Color = texture(u_Sampler").append(i).append(", ").append(texCoord).append(");\n");
+            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("  // 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
+        // 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";
@@ -107,6 +113,16 @@ public final class FragmentShaderGenerator {
             }
             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) {
@@ -273,21 +289,27 @@ public final class FragmentShaderGenerator {
         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 (color.a >= u_AlphaRef) discard;\n");
-            case GL11.GL_EQUAL ->
-                sb.append("  if (color.a != u_AlphaRef) discard;\n");
+                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 (color.a > u_AlphaRef) discard;\n");
+                sb.append("  if (qa > u_AlphaRef * 255.0) discard;\n");
             case GL11.GL_GREATER ->
-                sb.append("  if (color.a <= u_AlphaRef) discard;\n");
-            case GL11.GL_NOTEQUAL ->
-                sb.append("  if (color.a == u_AlphaRef) discard;\n");
+                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 (color.a < u_AlphaRef) discard;\n");
+                sb.append("  if (qa < u_AlphaRef * 255.0) discard;\n");
             case GL11.GL_ALWAYS -> {}
         }
     }

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

@@ -22,12 +22,10 @@ public final class GeometryShaderGenerator {
         if (key.separateSpecular()) {
             sb.append("in vec3 v_SpecularColor_gs[];\n");
         }
-        if (key.textureEnabled() || key.hasVertexTexCoord() || key.texGenEnabled()) {
-            sb.append("in vec4 v_TexCoord0_gs[];\n");
-        }
-        if (key.lightmapEnabled()) {
-            sb.append("in vec4 v_TexCoord1_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");
         }
@@ -37,12 +35,10 @@ public final class GeometryShaderGenerator {
         if (key.separateSpecular()) {
             sb.append("out vec3 v_SpecularColor;\n");
         }
-        if (key.textureEnabled() || key.hasVertexTexCoord() || key.texGenEnabled()) {
-            sb.append("out vec4 v_TexCoord0;\n");
-        }
-        if (key.lightmapEnabled()) {
-            sb.append("out vec4 v_TexCoord1;\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");
         }
@@ -82,12 +78,10 @@ public final class GeometryShaderGenerator {
         if (key.separateSpecular()) {
             sb.append("    v_SpecularColor = v_SpecularColor_gs").append(idx).append(";\n");
         }
-        if (key.textureEnabled() || key.hasVertexTexCoord() || 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(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");
         }

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

@@ -2,10 +2,8 @@ package com.gtnewhorizons.angelica.glsm.ffp;
 
 import com.gtnewhorizons.angelica.glsm.GLDebug;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
-import com.gtnewhorizons.angelica.glsm.RenderSystem;
+import com.gtnewhorizons.angelica.glsm.backend.RenderBackend;
 import lombok.Getter;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL20;
 import org.lwjgl.opengl.GL32;
@@ -15,30 +13,41 @@ 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 Logger LOGGER = LogManager.getLogger("FFPProgram");
     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 int locTextureMatrix0 = -1;
+    public final int[] locTextureMatrix = { -1, -1, -1, -1 };
 
     // Current state defaults
     public int locCurrentNormal = -1;
     public int locCurrentColor = -1;
-    public int locCurrentTexCoord = -1;
+    public final int[] locCurrentTexCoord = { -1, -1, -1, -1 };
     public int locCurrentLightmapCoord = -1;
     public int locLightmapTextureMatrix = -1;
 
@@ -93,6 +102,7 @@ public class Program {
     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;
 
@@ -108,11 +118,13 @@ public class Program {
         locProjectionMatrix = loc("u_ProjectionMatrix");
         locMVPMatrix = loc("u_MVPMatrix");
         locNormalMatrix = loc("u_NormalMatrix");
-        locTextureMatrix0 = loc("u_TextureMatrix0");
+        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");
-        locCurrentTexCoord = loc("u_CurrentTexCoord");
         locCurrentLightmapCoord = loc("u_CurrentLightmapCoord");
         locLightmapTextureMatrix = loc("u_LightmapTextureMatrix");
 
@@ -170,22 +182,24 @@ public class Program {
         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 GL20.glGetUniformLocation(programId, name);
+        return RENDER_BACKEND.getUniformLocation(programId, name);
     }
 
     public void destroy() {
-        GL20.glDeleteProgram(programId);
+        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;
@@ -200,16 +214,16 @@ public class Program {
                 shaders[shaderCount++] = compileShader(GL32.GL_GEOMETRY_SHADER, geomSrc, "ffp_g_" + id);
             }
 
-            program = GL20.glCreateProgram();
-            for (int i = 0; i < shaderCount; i++) GL20.glAttachShader(program, shaders[i]);
-            GL20.glLinkProgram(program);
+            program = backend.createProgram();
+            for (int i = 0; i < shaderCount; i++) backend.attachShader(program, shaders[i]);
+            backend.linkProgram(program);
 
-            final String log = RenderSystem.getProgramInfoLog(program);
+            final String log = backend.getProgramInfoLog(program, backend.getProgrami(program, GL20.GL_INFO_LOG_LENGTH));
             if (!log.isEmpty()) {
-                LOGGER.warn("FFP program link log (vk=0x{}, fk={}): {}", vkHex, fk, log);
+                GLStateManager.LOGGER.warn("FFP program link log (vk=0x{}, fk={}): {}", vkHex, fk, log);
             }
 
-            if (GL20.glGetProgrami(program, GL20.GL_LINK_STATUS) != GL11.GL_TRUE) {
+            if (backend.getProgrami(program, GL20.GL_LINK_STATUS) != GL11.GL_TRUE) {
                 throw new RuntimeException("FFP shader link failed (vk=0x" + vkHex + ", fk=" + fk + "): " + log);
             }
 
@@ -218,32 +232,33 @@ public class Program {
 
             // Detach and delete individual shaders — they're linked into the program
             for (int i = 0; i < shaderCount; i++) {
-                GL20.glDetachShader(program, shaders[i]);
-                GL20.glDeleteShader(shaders[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();
-            GL20.glUseProgram(program);
+            backend.useProgram(program);
             for (int i = 0; i < 4; i++) {
-                if (ffpProgram.locSampler[i] != -1) GL20.glUniform1i(ffpProgram.locSampler[i], i);
+                if (ffpProgram.locSampler[i] != -1) backend.uniform1i(ffpProgram.locSampler[i], i);
             }
-            GL20.glUseProgram(previousProgram);
+            backend.useProgram(previousProgram);
 
             return ffpProgram;
         } catch (RuntimeException e) {
-            if (program != 0) GL20.glDeleteProgram(program);
-            for (int i = 0; i < shaderCount; i++) GL20.glDeleteShader(shaders[i]);
+            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 int shader = GL20.glCreateShader(type);
-        GL20.glShaderSource(shader, src);
-        GL20.glCompileShader(shader);
+        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";
@@ -256,15 +271,15 @@ public class Program {
         };
         GLDebug.nameObject(KHRDebug.GL_SHADER, shader, name + "(" + typeName + ")");
 
-        final String log = RenderSystem.getShaderInfoLog(shader);
+        final String log = backend.getShaderInfoLog(shader, backend.getShaderi(shader, GL20.GL_INFO_LOG_LENGTH));
         if (!log.isEmpty()) {
-            LOGGER.warn("FFP {} shader compilation log for {}: {}", typeName, name, log);
+            GLStateManager.LOGGER.warn("FFP {} shader compilation log for {}: {}", typeName, name, log);
         }
 
-        final int result = GL20.glGetShaderi(shader, GL20.GL_COMPILE_STATUS);
+        final int result = backend.getShaderi(shader, GL20.GL_COMPILE_STATUS);
         if (result != GL11.GL_TRUE) {
-            LOGGER.error("FFP {} shader source:\n{}", typeName, src);
-            GL20.glDeleteShader(shader);
+            GLStateManager.LOGGER.error("FFP {} shader source:\n{}", typeName, src);
+            backend.deleteShader(shader);
             throw new RuntimeException("FFP " + typeName + " shader compilation failed for " + name + ": " + log);
         }
 

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

@@ -2,8 +2,7 @@ package com.gtnewhorizons.angelica.glsm.ffp;
 
 import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import lombok.Setter;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -26,7 +25,6 @@ import java.util.IdentityHashMap;
  * </pre>
  */
 public class ShaderCache {
-    private static final Logger LOGGER = LogManager.getLogger("FFPShaderCache");
     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)
@@ -123,7 +121,7 @@ public class ShaderCache {
 
         setLastUsed(vkPacked, fkPacked, fkLen, program);
 
-        LOGGER.debug("FFP variant compiled: {} + {} (total: {} programs)", vk, fk, count);
+        GLStateManager.LOGGER.debug("FFP variant compiled: {} + {} (total: {} programs)", vk, fk, count);
 
         if (dumpDir != null) {
             dumpShader(Long.toHexString(vkPacked), ".vert.glsl", vertSrc);
@@ -234,7 +232,7 @@ public class ShaderCache {
                 Files.writeString(file, source, StandardCharsets.UTF_8);
             }
         } catch (IOException e) {
-            LOGGER.warn("Failed to dump FFP shader to {}: {}", dumpDir, e.getMessage());
+            GLStateManager.LOGGER.warn("Failed to dump FFP shader to {}: {}", dumpDir, e.getMessage());
         }
     }
 
@@ -256,10 +254,10 @@ public class ShaderCache {
             for (var entry : geometrySourceCache.entrySet()) {
                 dumpShader(Long.toHexString(entry.getKey()), ".geom.glsl", entry.getValue());
             }
-            LOGGER.info("Dumped {} vertex, {} geometry, and {} fragment FFP shader sources to {}",
+            GLStateManager.LOGGER.info("Dumped {} vertex, {} geometry, and {} fragment FFP shader sources to {}",
                 vertexSourceCache.size(), geometrySourceCache.size(), seen.size(), outputDir);
         } catch (IOException e) {
-            LOGGER.warn("Failed to dump FFP shaders: {}", e.getMessage());
+            GLStateManager.LOGGER.warn("Failed to dump FFP shaders: {}", e.getMessage());
         }
     }
 
@@ -279,7 +277,7 @@ public class ShaderCache {
         geometrySourceCache.clear();
         lastProgram = null;
         lastVK = Long.MIN_VALUE;
-        LOGGER.debug("FFP shader cache cleared");
+        GLStateManager.LOGGER.debug("FFP shader cache cleared");
     }
 
     public int getProgramCount() {

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

@@ -0,0 +1,174 @@
+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.stacks.Vec3fStack;
+import com.gtnewhorizons.angelica.glsm.stacks.Vec4fStack;
+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() {
+        enabled = true;
+
+        GLStateManager.LOGGER.info("FFP shader emulation enabled");
+    }
+
+    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

@@ -6,16 +6,17 @@ 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 net.minecraft.client.renderer.OpenGlHelper;
+import com.gtnewhorizons.angelica.glsm.hooks.GLSMConfig;
+import org.joml.Math;
 import org.joml.Matrix3f;
 import org.joml.Matrix4f;
 import org.joml.Vector4f;
-import org.lwjgl.opengl.GL20;
 
 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.
@@ -42,119 +43,102 @@ public class Uniforms {
     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 = Math.log(2.0);
-    private static final double SQRT_LN2 = Math.sqrt(LN2);
-
-    // Dirty tracking: last-uploaded generation per category + program ID.
-    // Program change forces full re-upload since uniform locations differ.
-    private int lastProgramId = -1;
-    private int lastMvGen = -1;
-    private int lastProjGen = -1;
-    private int lastTexMatGen = -1;
-    private int lastLightingGen = -1;
-    private int lastFragmentGen = -1;
-    private int lastColorGen = -1;
-    private int lastNormalGen = -1;
-    private int lastTexCoordGen = -1;
-    private float lastLightmapX = Float.NaN;
-    private float lastLightmapY = Float.NaN;
-    private int lastTexGenGen = -1;
-    private int lastClipPlaneGen = -1;
-    private float lastLineWidth = Float.NaN;
-    private int lastViewportWidth = -1;
-    private int lastViewportHeight = -1;
+    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 boolean programChanged = program.getProgramId() != lastProgramId;
-        lastProgramId = program.getProgramId();
+        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 = programChanged || mvGen != lastMvGen;
-        final boolean projChanged = programChanged || projGen != lastProjGen;
-        final boolean texMatChanged = programChanged || texMatGen != lastTexMatGen;
+        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, projChanged, texMatChanged);
-            lastMvGen = mvGen;
-            lastProjGen = projGen;
-            lastTexMatGen = texMatGen;
+            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 (programChanged || litGen != lastLightingGen) {
+            if (litGen != st.lightingGen) {
                 uploadLighting(program);
-                lastLightingGen = litGen;
+                st.lightingGen = litGen;
             }
         }
 
         // Current color/normal/texcoord — skip if generation unchanged
         if (!program.getVertexKey().hasVertexColor()) {
             final int colorGen = GLStateManager.colorGeneration;
-            if (programChanged || colorGen != lastColorGen) {
+            if (colorGen != st.colorGen) {
                 uploadCurrentColor(program);
-                lastColorGen = colorGen;
+                st.colorGen = colorGen;
             }
         }
 
         if (!program.getVertexKey().hasVertexNormal() && program.getVertexKey().lightingEnabled()) {
             final int normalGen = ShaderManager.getNormalGeneration();
-            if (programChanged || normalGen != lastNormalGen) {
+            if (normalGen != st.normalGen) {
                 uploadCurrentNormal(program);
-                lastNormalGen = normalGen;
+                st.normalGen = normalGen;
             }
         }
 
-        if (!program.getVertexKey().hasVertexTexCoord() && program.getVertexKey().textureEnabled()) {
+        if (program.getVertexKey().anyUnitTexCoordEnabled()) {
             final int texGen = ShaderManager.getTexCoordGeneration();
-            if (programChanged || texGen != lastTexCoordGen) {
-                uploadCurrentTexCoord(program);
-                lastTexCoordGen = texGen;
+            if (texGen != st.texCoordGen) {
+                uploadCurrentTexCoords(program);
+                st.texCoordGen = texGen;
             }
         }
 
         if (program.getVertexKey().lightmapEnabled() && !program.getVertexKey().hasVertexLightmap()) {
-            if (programChanged || OpenGlHelper.lastBrightnessX != lastLightmapX || OpenGlHelper.lastBrightnessY != lastLightmapY) {
+            if (GLSMConfig.lastBrightnessX != st.lightmapX || GLSMConfig.lastBrightnessY != st.lightmapY) {
                 uploadCurrentLightmapCoord(program);
-                lastLightmapX = OpenGlHelper.lastBrightnessX;
-                lastLightmapY = OpenGlHelper.lastBrightnessY;
+                st.lightmapX = GLSMConfig.lastBrightnessX;
+                st.lightmapY = GLSMConfig.lastBrightnessY;
             }
         }
 
         if (program.getVertexKey().texGenEnabled()) {
             final int tgGen = GLStateManager.texGenGeneration;
-            if (programChanged || tgGen != lastTexGenGen) {
+            if (tgGen != st.texGenGen) {
                 uploadTexGen(program);
-                lastTexGenGen = tgGen;
+                st.texGenGen = tgGen;
             }
         }
 
         if (program.getVertexKey().clipPlanesEnabled()) {
             final int cpGen = GLStateManager.clipPlaneGeneration;
-            if (programChanged || cpGen != lastClipPlaneGen) {
+            if (cpGen != st.clipPlaneGen) {
                 uploadClipPlanes(program);
-                lastClipPlaneGen = cpGen;
+                st.clipPlaneGen = cpGen;
             }
         }
 
         final int fragGen = GLStateManager.fragmentGeneration;
-        if (programChanged || fragGen != lastFragmentGen) {
+        if (fragGen != st.fragmentGen) {
             uploadFragmentUniforms(program);
-            lastFragmentGen = fragGen;
+            st.fragmentGen = fragGen;
         }
 
         // Wide line emulation uniforms
         if (program.locLineWidth != -1 && program.locViewportSize != -1) {
-            uploadWideLineUniforms(program, programChanged);
+            uploadWideLineUniforms(program);
         }
     }
 
-    private void uploadMatrices(Program program, boolean mvChanged, boolean projChanged, boolean texMatChanged) {
+    private void uploadMatrices(Program program, boolean mvChanged, boolean mvLinearChanged, boolean projChanged, boolean texMatChanged) {
         final Matrix4f mv = GLStateManager.getModelViewMatrix();
         final Matrix4f proj = GLStateManager.getProjectionMatrix();
 
@@ -162,23 +146,25 @@ public class Uniforms {
         if (mvChanged) {
             if (program.locModelViewMatrix != -1) {
                 mv.get(mat4Buf);
-                GL20.glUniformMatrix4(program.locModelViewMatrix, false, 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);
-                GL20.glUniformMatrix3(program.locNormalMatrix, false, 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();
-                GL20.glUniform1f(program.locNormalScale, scale);
+                RENDER_BACKEND.uniform1f(program.locNormalScale, scale);
             }
         }
 
@@ -186,7 +172,7 @@ public class Uniforms {
         if (projChanged) {
             if (program.locProjectionMatrix != -1) {
                 proj.get(mat4Buf);
-                GL20.glUniformMatrix4(program.locProjectionMatrix, false, mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(program.locProjectionMatrix, false, mat4Buf);
             }
         }
 
@@ -194,23 +180,22 @@ public class Uniforms {
         if ((mvChanged || projChanged) && program.locMVPMatrix != -1) {
             proj.mul(mv, mvpMatrix);
             mvpMatrix.get(mat4Buf);
-            GL20.glUniformMatrix4(program.locMVPMatrix, false, mat4Buf);
+            RENDER_BACKEND.uniformMatrix4(program.locMVPMatrix, false, mat4Buf);
         }
 
-        // Texture matrices
+        // Texture matrices (per-unit).
         if (texMatChanged) {
-            // Texture matrix unit 0
-            if (program.locTextureMatrix0 != -1) {
-                final Matrix4f texMat = GLStateManager.getTextures().getTextureUnitMatrix(0);
-                texMat.get(mat4Buf);
-                GL20.glUniformMatrix4(program.locTextureMatrix0, false, mat4Buf);
+            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);
+                }
             }
-
-            // Texture matrix unit 1 (lightmap)
             if (program.locLightmapTextureMatrix != -1) {
                 final Matrix4f lmTexMat = GLStateManager.getTextures().getTextureUnitMatrix(1);
                 lmTexMat.get(mat4Buf);
-                GL20.glUniformMatrix4(program.locLightmapTextureMatrix, false, mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(program.locLightmapTextureMatrix, false, mat4Buf);
             }
         }
     }
@@ -238,7 +223,7 @@ public class Uniforms {
         uploadVec4(program.locMaterialDiffuse, mat.diffuse);
         uploadVec4(program.locMaterialSpecular, mat.specular);
         if (program.locMaterialShininess != -1) {
-            GL20.glUniform1f(program.locMaterialShininess, mat.shininess);
+            RENDER_BACKEND.uniform1f(program.locMaterialShininess, mat.shininess);
         }
 
         if (vk.light0Enabled()) {
@@ -277,7 +262,7 @@ public class Uniforms {
         }
 
         if (program.locMaterialShininess != -1) {
-            GL20.glUniform1f(program.locMaterialShininess, mat.shininess);
+            RENDER_BACKEND.uniform1f(program.locMaterialShininess, mat.shininess);
         }
 
         // Per-light products
@@ -307,32 +292,35 @@ public class Uniforms {
         vec3Buf.put(lightVal.y * materialVal.y);
         vec3Buf.put(lightVal.z * materialVal.z);
         vec3Buf.flip();
-        GL20.glUniform3(loc, vec3Buf);
+        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();
-        vec4Buf.put(color.getRed());
-        vec4Buf.put(color.getGreen());
-        vec4Buf.put(color.getBlue());
-        vec4Buf.put(color.getAlpha());
-        vec4Buf.flip();
-        GL20.glUniform4(program.locCurrentColor, vec4Buf);
+        tempVec4.get(vec4Buf);
+        RENDER_BACKEND.uniform4(program.locCurrentColor, vec4Buf);
     }
 
-    private void uploadCurrentTexCoord(Program program) {
-        if (program.locCurrentTexCoord == -1) return;
-        final var tc = ShaderManager.getCurrentTexCoord();
-        uploadVec4(program.locCurrentTexCoord, tc);
+    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;
-        GL20.glUniform2f(program.locCurrentLightmapCoord,
-            OpenGlHelper.lastBrightnessX, OpenGlHelper.lastBrightnessY);
+        RENDER_BACKEND.uniform2f(program.locCurrentLightmapCoord,
+            GLSMConfig.lastBrightnessX, GLSMConfig.lastBrightnessY);
     }
 
     private void uploadCurrentNormal(Program program) {
@@ -340,11 +328,8 @@ public class Uniforms {
         // Upload current normal from FFPShaderManager's tracked normal
         final var normal = ShaderManager.getCurrentNormal();
         vec3Buf.clear();
-        vec3Buf.put(normal.x);
-        vec3Buf.put(normal.y);
-        vec3Buf.put(normal.z);
-        vec3Buf.flip();
-        GL20.glUniform3(program.locCurrentNormal, vec3Buf);
+        normal.get(vec3Buf);
+        RENDER_BACKEND.uniform3(program.locCurrentNormal, vec3Buf);
     }
 
     private void uploadTexGen(Program program) {
@@ -379,12 +364,9 @@ public class Uniforms {
     private void uploadPlane(int loc, float[] plane) {
         if (loc == -1) return;
         vec4Buf.clear();
-        vec4Buf.put(plane[0]);
-        vec4Buf.put(plane[1]);
-        vec4Buf.put(plane[2]);
-        vec4Buf.put(plane[3]);
+        vec4Buf.put(plane, 0, 4);
         vec4Buf.flip();
-        GL20.glUniform4(loc, vec4Buf);
+        RENDER_BACKEND.uniform4(loc, vec4Buf);
     }
 
     private void uploadClipPlanes(Program program) {
@@ -395,7 +377,7 @@ public class Uniforms {
             cps.putEyePlane(i, clipPlaneBuf);
         }
         clipPlaneBuf.flip();
-        GL20.glUniform4(program.locClipPlanes, clipPlaneBuf);
+        RENDER_BACKEND.uniform4(program.locClipPlanes, clipPlaneBuf);
     }
 
     private void uploadFragmentUniforms(Program program) {
@@ -403,7 +385,7 @@ public class Uniforms {
 
         // Alpha test reference
         if (fk.alphaTestEnabled() && program.locAlphaRef != -1) {
-            GL20.glUniform1f(program.locAlphaRef, GLStateManager.getAlphaState().getReference());
+            RENDER_BACKEND.uniform1f(program.locAlphaRef, GLStateManager.getAlphaState().getReference());
         }
 
         // Per-unit tex env color
@@ -416,10 +398,20 @@ public class Uniforms {
                 vec4Buf.put(envState.envColorB);
                 vec4Buf.put(envState.envColorA);
                 vec4Buf.flip();
-                GL20.glUniform4(program.locTexEnvColor[i], vec4Buf);
+                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);
@@ -444,7 +436,7 @@ public class Uniforms {
             vec4Buf.put((float)(density / LN2));        // [2]: density/ln(2)
             vec4Buf.put((float)(density / SQRT_LN2));  // [3]: density/sqrt(ln(2))
             vec4Buf.flip();
-            GL20.glUniform4(program.locFogParams, vec4Buf);
+            RENDER_BACKEND.uniform4(program.locFogParams, vec4Buf);
         }
 
         if (program.locFogColor != -1) {
@@ -454,34 +446,31 @@ public class Uniforms {
             vec4Buf.put((float) fog.getFogColor().z);
             vec4Buf.put(fog.getFogAlpha());
             vec4Buf.flip();
-            GL20.glUniform4(program.locFogColor, vec4Buf);
+            RENDER_BACKEND.uniform4(program.locFogColor, vec4Buf);
         }
     }
 
-    private void uploadWideLineUniforms(Program program, boolean programChanged) {
+    private void uploadWideLineUniforms(Program program) {
+        final Program.UploadState st = program.uploadState;
         final float lineWidth = GLStateManager.getLineState().getWidth();
-        if (programChanged || lineWidth != lastLineWidth) {
-            GL20.glUniform1f(program.locLineWidth, lineWidth);
-            lastLineWidth = lineWidth;
+        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 (programChanged || vw != lastViewportWidth || vh != lastViewportHeight) {
-            GL20.glUniform2f(program.locViewportSize, vw, vh);
-            lastViewportWidth = vw;
-            lastViewportHeight = vh;
+        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();
-        vec4Buf.put(v.x);
-        vec4Buf.put(v.y);
-        vec4Buf.put(v.z);
-        vec4Buf.put(v.w);
-        vec4Buf.flip();
-        GL20.glUniform4(loc, vec4Buf);
+        v.get(vec4Buf);
+        RENDER_BACKEND.uniform4(loc, vec4Buf);
     }
 
     public void destroy() {

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

@@ -1,8 +1,10 @@
 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;
@@ -10,9 +12,14 @@ 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;
@@ -23,26 +30,26 @@ public final class VertexKey {
     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;
+    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;
-    private static final int BIT_TEXTURE             = 12;
-    private static final int BIT_LIGHTMAP            = 13;
-    private static final int BIT_TEX_MATRIX          = 14;
-    private static final int BIT_HAS_VERTEX_COLOR    = 15;
-    private static final int BIT_HAS_VERTEX_NORMAL   = 16;
-    private static final int BIT_HAS_VERTEX_TEX      = 17;
-    private static final int BIT_HAS_VERTEX_LIGHTMAP = 18;
-    private static final int BIT_COLOR_MAT_MODE      = 19;
-    // bits 19-21: colorMaterialMode (3 bits)
-    // TexGen modes: 3 bits each (0=NONE, 1=OBJ_LINEAR, 2=EYE_LINEAR)
-    private static final int BIT_TEXGEN_S            = 22;
-    private static final int BIT_TEXGEN_T            = 25;
-    private static final int BIT_TEXGEN_R            = 28;
-    private static final int BIT_TEXGEN_Q            = 31;
-    // bits 31-33: texGenModeQ (3 bits)
-    private static final int BIT_CLIP_PLANES         = 34;
-    private static final int BIT_WIDE_LINE           = 35;
+    // 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;
@@ -71,38 +78,30 @@ public final class VertexKey {
     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 textureEnabled()        { return bit(BIT_TEXTURE); }
-    public boolean lightmapEnabled()       { return bit(BIT_LIGHTMAP); }
-    public boolean textureMatrixEnabled()  { return bit(BIT_TEX_MATRIX); }
+    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). */
+    /** 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); }
-    /** TexGen mode for T coordinate. */
     public int texGenModeT()              { return (int)((packed >> BIT_TEXGEN_T) & 0x7); }
-    /** TexGen mode for R coordinate. */
     public int texGenModeR()              { return (int)((packed >> BIT_TEXGEN_R) & 0x7); }
-    /** TexGen mode for Q coordinate. */
     public int texGenModeQ()              { return (int)((packed >> BIT_TEXGEN_Q) & 0x7); }
-    /** Whether any texgen coordinate is enabled. */
     public boolean texGenEnabled()        { return texGenModeS() != TG_NONE || texGenModeT() != TG_NONE || texGenModeR() != TG_NONE || texGenModeQ() != TG_NONE; }
-    /** Whether any clip plane is enabled. */
     public boolean clipPlanesEnabled()    { return bit(BIT_CLIP_PLANES); }
-    /** Whether wide line GS emulation is active for this variant. */
     public boolean wideLineEmulation()   { return bit(BIT_WIDE_LINE); }
 
-    /** Whether vertex color replaces material ambient in this variant. */
     public boolean cmReplacesAmbient()    { final int m = colorMaterialMode(); return m == CM_AMBIENT || m == CM_AMBIENT_AND_DIFFUSE; }
-    /** Whether vertex color replaces material diffuse in this variant. */
     public boolean cmReplacesDiffuse()    { final int m = colorMaterialMode(); return m == CM_DIFFUSE || m == CM_AMBIENT_AND_DIFFUSE; }
-    /** Whether vertex color replaces material specular in this variant. */
     public boolean cmReplacesSpecular()   { return colorMaterialMode() == CM_SPECULAR; }
-    /** Whether vertex color replaces material emission in this variant. */
     public boolean cmReplacesEmission()   { return colorMaterialMode() == CM_EMISSION; }
 
     private boolean bit(int pos) { return ((packed >> pos) & 1) != 0; }
@@ -126,7 +125,7 @@ public final class VertexKey {
         };
     }
 
-    public static long packFromState(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap) {
+    public static long packFromState(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap, int fragUnitMask) {
         long bits = 0;
 
         final boolean lighting = GLStateManager.getLightingState().isEnabled();
@@ -171,23 +170,18 @@ public final class VertexKey {
             bits |= (1L << BIT_RESCALE_NORMAL);
         }
 
-        // Texture unit 0 (base texture)
-        if (GLStateManager.getTextures().getTextureUnitStates(0).isEnabled()) {
-            bits |= (1L << BIT_TEXTURE);
-        }
-        // Texture unit 1 (lightmap)
-        if (GLStateManager.getTextures().getTextureUnitStates(1).isEnabled()) {
-            bits |= (1L << BIT_LIGHTMAP);
+        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));
+            }
         }
 
-        // Check if texture matrix unit 0 is non-identity
-        final Matrix4f texMat = GLStateManager.getTextures().getTextureUnitMatrix(0);
-        if (!DisplayListManager.isIdentity(texMat)) {
-            bits |= (1L << BIT_TEX_MATRIX);
-        }
-
-        // TexGen (unit 0 only) — encode per-coordinate mode if enabled
-        final var texUnit = GLStateManager.getTextures();
+        // 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) {
@@ -210,9 +204,9 @@ public final class VertexKey {
             bits |= ((long) m & 0x7) << BIT_TEXGEN_Q;
             if (m != TG_NONE) anyTexGen = true;
         }
-        // Force texture matrix on when texgen is active (end portal pattern always uses it)
+        // Force unit-0 texture matrix on when texgen is active (end portal pattern always uses it).
         if (anyTexGen) {
-            bits |= (1L << BIT_TEX_MATRIX);
+            bits |= (1L << BIT_UNIT_TEXMAT_BASE);
         }
 
         // Vertex format flags
@@ -221,12 +215,14 @@ public final class VertexKey {
         if (hasTexCoord) bits |= (1L << BIT_HAS_VERTEX_TEX);
         if (hasLightmap) bits |= (1L << BIT_HAS_VERTEX_LIGHTMAP);
 
-        // Clip planes
+        if (GLStateManager.consumeUnit23TexCoordSetDuringDraw() && hasTexCoord) {
+            bits |= (1L << BIT_UNIT23_UV_FROM_UNIT0);
+        }
+
         if (GLStateManager.anyClipPlaneEnabled()) {
             bits |= (1L << BIT_CLIP_PLANES);
         }
 
-        // Wide line GS emulation
         if (GLStateManager.wideLineEmulationActive) {
             bits |= (1L << BIT_WIDE_LINE);
         }
@@ -234,8 +230,8 @@ public final class VertexKey {
         return bits;
     }
 
-    public static VertexKey fromState(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap) {
-        return new VertexKey(packFromState(hasColor, hasNormal, hasTexCoord, hasLightmap));
+    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) {
@@ -256,9 +252,11 @@ public final class VertexKey {
 
     @Override
     public String toString() {
-        return String.format("FFPVertexKey[0x%09X: lit=%b l0=%b l1=%b cm=%b fog=%b tex=%b lm=%b col=%b nrm=%b vtex=%b vlm=%b tg=%d/%d/%d/%d clip=%b wline=%b]",
+        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(), textureEnabled(), lightmapEnabled(),
+            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

@@ -42,6 +42,8 @@ public final class VertexShaderGenerator {
             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");
         }
@@ -76,11 +78,14 @@ public final class VertexShaderGenerator {
             sb.append("uniform mat3 u_NormalMatrix;\n");
         }
 
-        if (key.textureMatrixEnabled()) {
-            sb.append("uniform mat4 u_TextureMatrix0;\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
+        // 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");
@@ -98,9 +103,11 @@ public final class VertexShaderGenerator {
             sb.append("uniform vec4 u_CurrentColor;\n");
         }
 
-        if (!key.hasVertexTexCoord() && key.textureEnabled()) {
-            sb.append("uniform vec4 u_CurrentTexCoord;\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");
@@ -178,12 +185,15 @@ public final class VertexShaderGenerator {
         if (key.separateSpecular()) {
             sb.append("out vec3 v_SpecularColor;\n");
         }
-        if (key.textureEnabled() || key.hasVertexTexCoord() || key.texGenEnabled()) {
+        // 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");
         }
@@ -331,22 +341,18 @@ public final class VertexShaderGenerator {
     private static void emitTexCoordPassthrough(StringBuilder sb, VertexKey key) {
         if (key.texGenEnabled()) {
             emitTexGenCoordGeneration(sb, key);
-        } else if (key.textureEnabled() || key.hasVertexTexCoord()) {
-            sb.append("  // Texture coordinates\n");
-            if (key.hasVertexTexCoord()) {
-                if (key.textureMatrixEnabled()) {
-                    sb.append("  v_TexCoord0 = u_TextureMatrix0 * vec4(a_TexCoord0, 0.0, 1.0);\n");
-                } else {
-                    sb.append("  v_TexCoord0 = vec4(a_TexCoord0, 0.0, 1.0);\n");
-                }
+        } 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 {
-                if (key.textureMatrixEnabled()) {
-                    sb.append("  v_TexCoord0 = u_TextureMatrix0 * u_CurrentTexCoord;\n");
-                } else {
-                    sb.append("  v_TexCoord0 = u_CurrentTexCoord;\n");
-                }
+                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");
@@ -354,6 +360,18 @@ public final class VertexShaderGenerator {
                 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");
+            }
+        }
     }
 
     /**
@@ -367,7 +385,7 @@ public final class VertexShaderGenerator {
 
         emitTexGenComponent(sb, key.texGenModeS(), "s", "S", key);
         emitTexGenComponent(sb, key.texGenModeT(), "t", "T", key);
-        emitTexGenComponent(sb, key.texGenModeR(), "r", "R", 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)

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

@@ -16,17 +16,13 @@ public final class AccumulatedDraw {
     public final VertexFormat format;
     public final List<ByteBuffer> drawBuffers;
     public final int drawMode;
-    public final int commandIndex; // Position in command list for state tracking
-    public final int stateGeneration; // Position in command list for state tracking
     public RestoreData restoreData;
 
-    public AccumulatedDraw(DirectTessellator tessellator, int commandIndex, int stateGeneration, boolean copyLast) {
+    public AccumulatedDraw(DirectTessellator tessellator, boolean copyLast) {
         this.format = tessellator.getVertexFormat();
         this.drawMode = tessellator.drawMode;
         this.drawBuffers = new ArrayList<>();
         this.drawBuffers.add(tessellator.allocateBufferCopy());
-        this.commandIndex = commandIndex;
-        this.stateGeneration = stateGeneration;
 
         if (copyLast) {
             this.restoreData = new RestoreData(tessellator);
@@ -36,7 +32,6 @@ public final class AccumulatedDraw {
 
     public void mergeDraw(DirectTessellator tessellator, boolean copyLast) {
         this.drawBuffers.add(tessellator.allocateBufferCopy());
-
         if (copyLast) {
             this.restoreData = new RestoreData(tessellator);
         }

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

@@ -1,12 +1,10 @@
 package com.gtnewhorizons.angelica.glsm.recording;
 
-import com.gtnewhorizon.gtnhlib.client.opengl.UniversalVAO;
 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.GL11;
 import org.lwjgl.opengl.GL15;
 
 import java.nio.ByteBuffer;
@@ -14,7 +12,10 @@ import java.nio.DoubleBuffer;
 import java.nio.FloatBuffer;
 import java.nio.IntBuffer;
 
-import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.*;
+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
@@ -39,7 +40,13 @@ public final class CommandBufferExecutor {
      * @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, Object[] complexObjects, DisplayListVBO ownedVbos) {
+    public static void execute(
+        ByteBuffer buffer,
+        DisplayListCommand[] complexObjects,
+        DisplayListVBO ownedVbos,
+        int list,
+        CompiledDisplayList compiledDisplayList
+    ) {
         long ptr = memAddress(buffer);
         final long end = ptr + buffer.limit();
 
@@ -343,50 +350,6 @@ public final class CommandBufferExecutor {
                     GLStateManager.glTexParameterf(target, pname, param);
                 }
 
-                // === Double commands ===
-                case GLCommand.TRANSLATE -> {
-                    final double x = memGetDouble(ptr);
-                    final double y = memGetDouble(ptr + 8);
-                    final double z = memGetDouble(ptr + 16);
-                    ptr += 24;
-                    GLStateManager.glTranslated(x, y, z);
-                }
-                case GLCommand.ROTATE -> {
-                    final double angle = memGetDouble(ptr);
-                    final double x = memGetDouble(ptr + 8);
-                    final double y = memGetDouble(ptr + 16);
-                    final double z = memGetDouble(ptr + 24);
-                    ptr += 32;
-                    GLStateManager.glRotated(angle, x, y, z);
-                }
-                case GLCommand.SCALE -> {
-                    final double x = memGetDouble(ptr);
-                    final double y = memGetDouble(ptr + 8);
-                    final double z = memGetDouble(ptr + 16);
-                    ptr += 24;
-                    GLStateManager.glScaled(x, y, z);
-                }
-                case GLCommand.ORTHO -> {
-                    final double left = memGetDouble(ptr);
-                    final double right = memGetDouble(ptr + 8);
-                    final double bottom = memGetDouble(ptr + 16);
-                    final double top = memGetDouble(ptr + 24);
-                    final double zNear = memGetDouble(ptr + 32);
-                    final double zFar = memGetDouble(ptr + 40);
-                    ptr += 48;
-                    GLStateManager.glOrtho(left, right, bottom, top, zNear, zFar);
-                }
-                case GLCommand.FRUSTUM -> {
-                    final double left = memGetDouble(ptr);
-                    final double right = memGetDouble(ptr + 8);
-                    final double bottom = memGetDouble(ptr + 16);
-                    final double top = memGetDouble(ptr + 24);
-                    final double zNear = memGetDouble(ptr + 32);
-                    final double zFar = memGetDouble(ptr + 40);
-                    ptr += 48;
-                    GLStateManager.glFrustum(left, right, bottom, top, zNear, zFar);
-                }
-
                 // === Matrix commands ===
                 case GLCommand.MULT_MATRIX -> {
                     // Mode-agnostic: just multiply current matrix
@@ -398,6 +361,20 @@ public final class CommandBufferExecutor {
                     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++) {
@@ -490,10 +467,10 @@ public final class CommandBufferExecutor {
                     // Restore attributes based on flags
                     if ((flags & VertexFlags.COLOR_BIT) != 0) {
                         final int color = memGetInt(ptr + 8);
-                        byte a = (byte) ((color >> 24) & 0xFF);
-                        byte r = (byte) ((color >> 16) & 0xFF);
-                        byte g = (byte) ((color >> 8) & 0xFF);
-                        byte b = (byte) ((color & 0xFF));
+                        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) {
@@ -530,14 +507,6 @@ public final class CommandBufferExecutor {
                     ptr += 4 * MAX_DRAW_BUFFERS;
                     GLStateManager.glDrawBuffers(DRAW_BUFFERS_BUFFER);
                 }
-                case GLCommand.DRAW_ARRAYS -> {
-                    GLStateManager.glDrawArrays(memGetInt(ptr), memGetInt(ptr + 4), memGetInt(ptr + 8));
-                    ptr += 12;
-                }
-                case GLCommand.DRAW_ELEMENTS -> {
-                    GLStateManager.glDrawElements(memGetInt(ptr), memGetInt(ptr + 4), memGetInt(ptr + 8), memGetLong(ptr + 12));
-                    ptr += 20;
-                }
                 case GLCommand.BIND_VBO -> {
                     GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, memGetInt(ptr));
                     ptr += 4;
@@ -551,10 +520,10 @@ public final class CommandBufferExecutor {
                 case GLCommand.COMPLEX_REF -> {
                     final int index = memGetInt(ptr);
                     ptr += 4;
-                    ((DisplayListCommand) complexObjects[index]).execute();
+                    complexObjects[index].execute();
                 }
 
-                default -> throw new IllegalStateException("Unknown command opcode: " + cmd);
+                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

@@ -1,31 +1,34 @@
 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 java.util.List;
 
 import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.*;
 
-public final class CommandBuffer {
-    private static final int DEFAULT_CAPACITY = 4096; // Guess at typical display list size
+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 List<Object> complexObjects = new ArrayList<>();
+    private final ArrayList<DisplayListCommand> complexObjects = new ArrayList<>();
+    private final IndexedDrawBatchBuilder indexedDraws = new IndexedDrawBatchBuilder();
 
-    public CommandBuffer() {
+    public CommandRecorder() {
         this(DEFAULT_CAPACITY);
     }
 
-    public CommandBuffer(int initialCapacity) {
+    public CommandRecorder(int initialCapacity) {
         this.buffer = memAlloc(initialCapacity);
-        this.basePointer = memAddress(buffer);
+        this.basePointer = memAddress0(buffer);
         this.writePointer = basePointer;
     }
 
@@ -57,11 +60,26 @@ public final class CommandBuffer {
         if (remaining < needed) {
             final int newCapacity = Math.max(buffer.capacity() * 2, buffer.capacity() + needed);
             buffer = memRealloc(buffer, newCapacity);
-            basePointer = memAddress(buffer);
+            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) {
@@ -424,53 +442,22 @@ public final class CommandBuffer {
         writeFloat(param);
     }
 
-    // === Double commands ===
+    // === Transformation commands ===
 
-    public void writeTranslate(double x, double y, double z) {
-        ensureCapacity(28);
+    public void writeTranslate(Vector3f translationVector) {
+        ensureCapacity(16);
         writeInt(GLCommand.TRANSLATE);
-        writeDouble(x);
-        writeDouble(y);
-        writeDouble(z);
+        writeFloat(translationVector.x);
+        writeFloat(translationVector.y);
+        writeFloat(translationVector.z);
     }
 
-    public void writeRotate(double angle, double x, double y, double z) {
-        ensureCapacity(36);
-        writeInt(GLCommand.ROTATE);
-        writeDouble(angle);
-        writeDouble(x);
-        writeDouble(y);
-        writeDouble(z);
-    }
-
-    public void writeScale(double x, double y, double z) {
-        ensureCapacity(28);
+    public void writeScale(Vector3f scaleVector) {
+        ensureCapacity(16);
         writeInt(GLCommand.SCALE);
-        writeDouble(x);
-        writeDouble(y);
-        writeDouble(z);
-    }
-
-    public void writeOrtho(double left, double right, double bottom, double top, double zNear, double zFar) {
-        ensureCapacity(52);
-        writeInt(GLCommand.ORTHO);
-        writeDouble(left);
-        writeDouble(right);
-        writeDouble(bottom);
-        writeDouble(top);
-        writeDouble(zNear);
-        writeDouble(zFar);
-    }
-
-    public void writeFrustum(double left, double right, double bottom, double top, double zNear, double zFar) {
-        ensureCapacity(52);
-        writeInt(GLCommand.FRUSTUM);
-        writeDouble(left);
-        writeDouble(right);
-        writeDouble(bottom);
-        writeDouble(top);
-        writeDouble(zNear);
-        writeDouble(zFar);
+        writeFloat(scaleVector.x);
+        writeFloat(scaleVector.y);
+        writeFloat(scaleVector.z);
     }
 
     // === Matrix commands ===
@@ -594,29 +581,13 @@ public final class CommandBuffer {
         writeFloat(restoreData.lastTexCoordV);
     }
 
+
     public void writeCallList(int listId) {
         ensureCapacity(8);
         writeInt(GLCommand.CALL_LIST);
         writeInt(listId);
     }
 
-    public void writeDrawArrays(int mode, int start, int count) {
-        ensureCapacity(16);
-        writeInt(GLCommand.DRAW_ARRAYS);
-        writeInt(mode);
-        writeInt(start);
-        writeInt(count);
-    }
-
-    public void writeDrawElements(int mode, int indices_count, int type, long indices_buffer_offset) {
-        ensureCapacity(24);
-        writeInt(GLCommand.DRAW_ELEMENTS);
-        writeInt(mode);
-        writeInt(indices_count);
-        writeInt(type);
-        writeLong(indices_buffer_offset);
-    }
-
     public void writeBindVBO(int vbo) {
         ensureCapacity(8);
         writeInt(GLCommand.BIND_VBO);
@@ -664,7 +635,7 @@ public final class CommandBuffer {
 
     // === Complex object reference ===
 
-    public void writeComplexRef(DisplayListCommand cmd) {
+    public void writeComplexCommand(DisplayListCommand cmd) {
         ensureCapacity(8);
         final int index = complexObjects.size();
         complexObjects.add(cmd);
@@ -672,94 +643,52 @@ public final class CommandBuffer {
         writeInt(index);
     }
 
-    // === Reading methods for optimization pass ===
-
-    private long readPointer = 0;
-
-    /**
-     * Reset read position to the beginning of the buffer.
-     */
-    public void resetRead() {
-        readPointer = basePointer;
-    }
-
-    /**
-     * Check if there's more data to read.
-     */
-    public boolean hasRemaining() {
-        return readPointer < writePointer;
-    }
-
-    /**
-     * Read an int from the current position.
-     */
-    public int readInt() {
-        final int value = memGetInt(readPointer);
-        readPointer += 4;
-        return value;
-    }
-
-    public long readLong() {
-        final long value = memGetLong(readPointer);
-        readPointer += 8;
-        return value;
-    }
-
-    /**
-     * Read a float from the current position.
-     */
-    public float readFloat() {
-        final float value = memGetFloat(readPointer);
-        readPointer += 4;
-        return value;
-    }
-
-    /**
-     * Read a double from the current position.
-     */
-    public double readDouble() {
-        final double value = memGetDouble(readPointer);
-        readPointer += 8;
-        return value;
-    }
-
-    /**
-     * Read a Matrix4f from the current position (16 floats in column-major order).
-     */
-    public Matrix4f readMatrix4f(Matrix4f dest) {
-        dest.m00(readFloat()); dest.m01(readFloat()); dest.m02(readFloat()); dest.m03(readFloat());
-        dest.m10(readFloat()); dest.m11(readFloat()); dest.m12(readFloat()); dest.m13(readFloat());
-        dest.m20(readFloat()); dest.m21(readFloat()); dest.m22(readFloat()); dest.m23(readFloat());
-        dest.m30(readFloat()); dest.m31(readFloat()); dest.m32(readFloat()); dest.m33(readFloat());
-        return dest;
-    }
-
     // === Lifecycle ===
 
     public int size() {
         return (int) (writePointer - basePointer);
     }
 
-    public long address() {
-        return 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;
+        }
     }
 
-    public ByteBuffer toBuffer() {
-        buffer.limit(size());
-        buffer.position(0);
-        return buffer;
+    /**
+     * 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 Object[] getComplexObjects() {
-        return complexObjects.toArray();
+    public DisplayListCommand[] getComplexObjects() {
+        return complexObjects.toArray(new DisplayListCommand[complexObjects.size()]);
     }
 
-    public Object getComplexObject(int index) {
+    public DisplayListCommand getComplexObject(int index) {
         return complexObjects.get(index);
     }
 
     public boolean isEmpty() {
-        return size() == 0 && complexObjects.isEmpty();
+        return size() == 0;
     }
 
     /**
@@ -769,16 +698,4 @@ public final class CommandBuffer {
         writePointer = basePointer;
         complexObjects.clear();
     }
-
-    /**
-     * Free the underlying buffer. Must be called when done.
-     */
-    public void free() {
-        if (buffer != null) {
-            memFree(buffer);
-            buffer = null;
-            basePointer = 0;
-            writePointer = 0;
-        }
-    }
 }

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

@@ -2,12 +2,15 @@ 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;
@@ -26,24 +29,30 @@ 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);
+    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 Object[] complexObjects;      // Complex commands (TexImage2D, etc.)
+    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, Object[] complexObjects, DisplayListVBO ownedVbos) {
+    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);
+            CommandBufferExecutor.execute(commandBuffer, complexObjects, ownedVbos, list, this);
         }
     }
 
@@ -51,20 +60,24 @@ public final class CompiledDisplayList {
      * Delete all resources held by this display list.
      */
     public void delete() {
-        // Delete complex objects that hold resources
         if (complexObjects != null) {
-            for (Object obj : complexObjects) {
-                if (obj instanceof DisplayListCommand cmd) {
-                    cmd.delete();
-                }
+            for (DisplayListCommand cmd : complexObjects) {
+                cmd.delete();
             }
         }
 
-        // Close VBOs
+        // 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);
@@ -81,7 +94,7 @@ public final class CompiledDisplayList {
     /**
      * Get complex objects for inlining into another display list (nested lists).
      */
-    public Object[] getComplexObjects() {
+    public DisplayListCommand[] getComplexObjects() {
         return complexObjects;
     }
 
@@ -89,6 +102,10 @@ public final class CompiledDisplayList {
         return ownedVbos;
     }
 
+    public List<IndexedDrawBatch> getIndexedBatches() {
+        return indexedBatches;
+    }
+
     // === Test inspection methods ===
 
     /**
@@ -129,8 +146,20 @@ public final class CompiledDisplayList {
         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 DisplayListManager.getCompiledDisplayListString(0, this, null);
+        return toString(0);
     }
 }

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

@@ -23,6 +23,10 @@ public final class DisplayListVBO {
         return vbos;
     }
 
+    public SubVBO getVBO(int index) {
+        return vbos[index];
+    }
+
     public void render(int index) {
         vbos[index].render();
     }
@@ -41,6 +45,18 @@ public final class DisplayListVBO {
             this.count = count;
         }
 
+        public int getStart() {
+            return start;
+        }
+
+        public int getCount() {
+            return count;
+        }
+
+        public int getDrawMode() {
+            return drawMode;
+        }
+
         public void delete() {
             vao.delete();
         }

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

@@ -68,13 +68,19 @@ public final class DisplayListVBOBuilder {
                     allBuffers.addAll(drawBuffers);
                     int size = 0;
                     for (ByteBuffer buffer : drawBuffers) {
-                        size += buffer.remaining();
+                        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);
                 }

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

@@ -74,10 +74,7 @@ public final class GLCommand {
 
     // === Double commands ===
     public static final int TRANSLATE = 70;          // [cmd:4][mode:4][x:8d][y:8d][z:8d] = 32 bytes
-    public static final int ROTATE = 71;             // [cmd:4][mode:4][angle:8d][x:8d][y:8d][z:8d] = 40 bytes
     public static final int SCALE = 72;              // [cmd:4][mode:4][x:8d][y:8d][z:8d] = 32 bytes
-    public static final int ORTHO = 73;              // [cmd:4][left:8d][right:8d][bottom:8d][top:8d][zNear:8d][zFar:8d] = 52 bytes
-    public static final int FRUSTUM = 74;            // [cmd:4][left:8d][right:8d][bottom:8d][top:8d][zNear:8d][zFar:8d] = 52 bytes
     public static final int CLEAR_DEPTH = 75;        // [cmd:4][depth:8d] = 12 bytes
 
     // === Matrix commands (72 bytes) ===
@@ -97,8 +94,6 @@ public final class GLCommand {
     public static final int CALL_LIST = 102;         // [cmd:4][listId:4] = 8 bytes
 
 
-    public static final int DRAW_ARRAYS = 110;       // [cmd:4][drawMode:4][start:4][count:4] = 20 bytes
-    public static final int DRAW_ELEMENTS = 111;     // [cmd:4][mode:4][indices_count:4][type:4][indices_buffer_offset:8] = 28 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)
     /**
@@ -169,10 +164,7 @@ public final class GLCommand {
             case MATERIALF -> "MATERIALF";
             case TEX_PARAMETERF -> "TEX_PARAMETERF";
             case TRANSLATE -> "TRANSLATE";
-            case ROTATE -> "ROTATE";
             case SCALE -> "SCALE";
-            case ORTHO -> "ORTHO";
-            case FRUSTUM -> "FRUSTUM";
             case CLEAR_DEPTH -> "CLEAR_DEPTH";
             case MULT_MATRIX -> "MULT_MATRIX";
             case LOAD_MATRIX -> "LOAD_MATRIX";
@@ -219,7 +211,7 @@ public final class GLCommand {
             // Three int commands (16 bytes)
             case GLCommand.STENCIL_FUNC, GLCommand.STENCIL_OP, GLCommand.TEX_PARAMETERI,
                  GLCommand.LIGHTF, GLCommand.LIGHTI,
-                 GLCommand.MATERIALF, GLCommand.TEX_PARAMETERF, GLCommand.DRAW_ARRAYS -> 16;
+                 GLCommand.MATERIALF, GLCommand.TEX_PARAMETERF -> 16;
 
             // Four int commands (20 bytes)
             case GLCommand.VIEWPORT, GLCommand.BLEND_FUNC, GLCommand.COLOR_MASK,
@@ -227,8 +219,6 @@ public final class GLCommand {
                  GLCommand.SCISSOR,
                  GLCommand.COLOR, GLCommand.CLEAR_COLOR, GLCommand.BLEND_COLOR -> 20;
 
-            case GLCommand.DRAW_ELEMENTS -> 24;
-
             // DRAW_RANGE_RESTORE: 28 bytes
             case GLCommand.DRAW_RANGE_RESTORE -> 28;
 
@@ -239,10 +229,8 @@ public final class GLCommand {
             case GLCommand.DRAW_BUFFERS -> 40;
 
             // Double commands
-            case GLCommand.TRANSLATE, GLCommand.SCALE -> 28;  // cmd + 3 doubles
+            case GLCommand.TRANSLATE, GLCommand.SCALE -> 16;  // cmd + 3 floats
             case GLCommand.CLEAR_DEPTH -> 12;  // cmd + 1 double
-            case GLCommand.ROTATE -> 36;  // cmd + 4 doubles
-            case GLCommand.ORTHO, GLCommand.FRUSTUM -> 52;  // cmd + 6 doubles
 
             // Matrix commands
             case GLCommand.MULT_MATRIX, GLCommand.LOAD_MATRIX -> 68;  // cmd + 16 floats

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

@@ -1,15 +1,12 @@
 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.states.VertexAttribState;
-import com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import com.gtnewhorizons.angelica.glsm.ffp.VAOManager;
 import org.lwjgl.opengl.GL11;
-import org.lwjgl.opengl.GL15;
 
 import java.nio.ByteBuffer;
 import java.util.Arrays;
@@ -19,8 +16,7 @@ import java.util.Arrays;
  * Used both during display list compilation and for live immediate mode emulation in core profile.
  */
 public final class ImmediateModeRecorder {
-    private static final Logger LOGGER = LogManager.getLogger("ImmediateModeRecorder");
-    private static final DirectTessellator tessellator = new DirectTessellator(TessellatorManager.DEFAULT_BUFFER_SIZE);
+    private static final CallbackTessellator tessellator = new CallbackTessellator(TessellatorManager.DEFAULT_BUFFER_SIZE);
 
     /** Separate tessellator for the splash thread. Nulled after splash completes. */
     private static DirectTessellator splashTessellator;
@@ -34,6 +30,7 @@ public final class ImmediateModeRecorder {
     }
 
     public static void destroySplashTessellator() {
+        splashTessellator.delete();
         splashTessellator = null;
     }
 
@@ -168,19 +165,14 @@ public final class ImmediateModeRecorder {
         .mapToInt(Usage::getAttributeLocation)
             .max().orElse(0);
 
-    private static final ByteBuffer[] scratchAttribBuffers = new ByteBuffer[NUM_ATTRIBS];
-    private static final long[] scratchAttribBaseOffsets = new long[NUM_ATTRIBS];
-    private static final int[] scratchVBOIds = new int[NUM_ATTRIBS];
-    private static final ByteBuffer[] scratchVBOBuffers = new ByteBuffer[NUM_ATTRIBS];
-    private static final long[] scratchVBOReadOffsets = new long[NUM_ATTRIBS];
-
     private static final class AttribReader {
         ByteBuffer data;
         int stride;
         int baseOffset;
         int size;
         int loc;
-        VertexAttribState.Attrib attrib;
+        int type;
+        boolean normalized;
     }
 
     private static final AttribReader[] readers = new AttribReader[NUM_ATTRIBS];
@@ -199,167 +191,32 @@ public final class ImmediateModeRecorder {
      * 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 int readVBOCount = readbackAttribVBOs(first, count);
-
+        final AttribSnapshot snap = AttribSnapshot.snapshot(first, count);
         try {
-            prepareReaders();
+            prepareReaders(snap);
             if (positionReaderIndex < 0) return null;
             return readVerticesFromBuffer(mode, first, count);
         } finally {
-            freeReadbackBuffers(readVBOCount);
+            snap.free();
         }
     }
 
-    /**
-     * Process a glDrawElements call during display list recording when a VBO is bound.
-     */
-    public static DirectTessellator processDrawElementsFromVBO(int mode, int indicesCount, int indexType, long indicesOffset, int eboId) {
-        if (eboId == 0) return null;
-
-        final int readVBOCount = readbackAttribVBOs(-1, 0);
-
-        try {
-            prepareReaders();
-            if (positionReaderIndex < 0) return null;
-
-            final int prevEBO = GLStateManager.getBoundEBO();
-            GLStateManager.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, eboId);
-            final int eboSize = GL15.glGetBufferParameteri(GL15.GL_ELEMENT_ARRAY_BUFFER, GL15.GL_BUFFER_SIZE);
-            if (eboSize <= 0) {
-                GLStateManager.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEBO);
-                return null;
-            }
-
-            final int indexSize = VertexAttribState.Attrib.glTypeSizeBytes(indexType);
-            final int eboReadOffset = (int) indicesOffset;
-            final int eboReadSize = indicesCount * indexSize;
-            if (eboReadOffset + eboReadSize > eboSize) {
-                LOGGER.warn("[EBO] Read range {}+{} exceeds buffer size {}", eboReadOffset, eboReadSize, eboSize);
-                GLStateManager.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEBO);
-                return null;
-            }
-            final ByteBuffer eboData = MemoryUtilities.memAlloc(eboReadSize);
-            GL15.glGetBufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, eboReadOffset, eboData);
-            GLStateManager.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEBO);
-
-            try {
-                return readVerticesFromBufferIndexed(mode, eboData, indexType, 0, indicesCount);
-            } finally {
-                MemoryUtilities.memFree(eboData);
-            }
-        } finally {
-            freeReadbackBuffers(readVBOCount);
-        }
-    }
-
-    /**
-     * Read data for all enabled attribs into scratchAttribBuffers.
-     * For VBO-backed attribs, reads VBO data. For client-memory attribs, uses the client pointer directly.
-     */
-    private static int readbackAttribVBOs(int firstVertex, int vertexCount) {
-        int readVBOCount = 0;
-        final int prevVBO = GLStateManager.getBoundVBO();
-        final boolean partialRead = firstVertex >= 0;
-
-        for (int i = 0; i < NUM_ATTRIBS; i++) {
-            scratchAttribBuffers[i] = null;
-            scratchAttribBaseOffsets[i] = 0;
-            final VertexAttribState.Attrib a = VertexAttribState.get(i);
-            if (!a.enabled) continue;
-
-            if (a.vboId != 0) {
-                // VBO-backed attrib — read from GPU
-                ByteBuffer existing = null;
-                int existingIdx = -1;
-                for (int j = 0; j < readVBOCount; j++) {
-                    if (scratchVBOIds[j] == a.vboId) {
-                        existing = scratchVBOBuffers[j];
-                        existingIdx = j;
-                        break;
-                    }
-                }
-
-                if (existing != null) {
-                    scratchAttribBuffers[i] = existing;
-                    scratchAttribBaseOffsets[i] = scratchVBOReadOffsets[existingIdx];
-                } else {
-                    GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, a.vboId);
-                    final int bufferSize = GL15.glGetBufferParameteri(GL15.GL_ARRAY_BUFFER, GL15.GL_BUFFER_SIZE);
-                    if (bufferSize <= 0) {
-                        LOGGER.warn("[VBO Readback] GL_BUFFER_SIZE={} for VBO {}", bufferSize, a.vboId);
-                        continue;
-                    }
-
-                    final long readOffset;
-                    final int readSize;
-                    if (partialRead) {
-                        final int stride = a.effectiveStride();
-                        long rangeStart = a.offset + (long) firstVertex * stride;
-                        long rangeEnd = a.offset + (long) (firstVertex + vertexCount - 1) * stride + (long) a.size * a.typeSizeBytes();
-
-                        for (int k = 0; k < NUM_ATTRIBS; k++) {
-                            if (k == i) continue;
-                            final VertexAttribState.Attrib ak = VertexAttribState.get(k);
-                            if (!ak.enabled || ak.vboId != a.vboId) continue;
-                            final int ks = ak.effectiveStride();
-                            rangeStart = Math.min(rangeStart, ak.offset + (long) firstVertex * ks);
-                            rangeEnd = Math.max(rangeEnd, ak.offset + (long) (firstVertex + vertexCount - 1) * ks
-                                + (long) ak.size * ak.typeSizeBytes());
-                        }
-                        rangeStart = Math.max(0, rangeStart);
-                        rangeEnd = Math.min(bufferSize, rangeEnd);
-                        readOffset = rangeStart;
-                        readSize = (int) (rangeEnd - rangeStart);
-                    } else {
-                        readOffset = 0;
-                        readSize = bufferSize;
-                    }
-
-                    if (readSize <= 0) continue;
-
-                    final ByteBuffer buf = MemoryUtilities.memAlloc(readSize);
-                    GL15.glGetBufferSubData(GL15.GL_ARRAY_BUFFER, readOffset, buf);
-                    scratchAttribBuffers[i] = buf;
-                    scratchAttribBaseOffsets[i] = readOffset;
-                    scratchVBOIds[readVBOCount] = a.vboId;
-                    scratchVBOReadOffsets[readVBOCount] = readOffset;
-                    scratchVBOBuffers[readVBOCount] = buf;
-                    readVBOCount++;
-                }
-            } else if (a.clientPointer != null) {
-                // Client-memory attrib — use pointer directly (no allocation needed)
-                scratchAttribBuffers[i] = a.clientPointer;
-            }
-        }
-
-        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, prevVBO);
-
-        return readVBOCount;
-    }
-
-    private static void freeReadbackBuffers(int readVBOCount) {
-        for (int i = 0; i < readVBOCount; i++) {
-            MemoryUtilities.memFree(scratchVBOBuffers[i]);
-            scratchVBOBuffers[i] = null;
-        }
-    }
-
-    private static void prepareReaders() {
+    private static void prepareReaders(AttribSnapshot snap) {
         nonPositionCount = 0;
         positionReaderIndex = -1;
 
         for (int i = 0; i < NUM_ATTRIBS; i++) {
-            final ByteBuffer buf = scratchAttribBuffers[i];
-            if (buf == null) continue;
-            final VertexAttribState.Attrib a = VertexAttribState.get(i);
+            final AttribSnapshot.AttribDesc d = snap.get(i);
+            if (d == null) continue;
 
             final AttribReader r = readers[i];
-            r.data = buf;
-            r.stride = a.effectiveStride();
-            r.baseOffset = (int) (a.offset - scratchAttribBaseOffsets[i]);
-            r.size = a.size;
+            r.data = d.readBuffer();
+            r.stride = d.effectiveStride();
+            r.baseOffset = (int) (d.offset() - d.readBufferBaseOffset());
+            r.size = d.size();
             r.loc = i;
-            r.attrib = a;
+            r.type = d.type();
+            r.normalized = d.normalized();
 
             if (i == LOC_POSITION) {
                 positionReaderIndex = i;
@@ -380,18 +237,6 @@ public final class ImmediateModeRecorder {
         return end();
     }
 
-    private static DirectTessellator readVerticesFromBufferIndexed(int mode, ByteBuffer eboData, int indexType, int eboOffset, int indicesCount) {
-        begin(mode);
-        final DirectTessellator t = tessellator();
-
-        for (int i = 0; i < indicesCount; i++) {
-            final int index = readIndex(eboData, indexType, eboOffset, i);
-            readVertexFromBuffer(t, index);
-        }
-
-        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;
@@ -412,39 +257,75 @@ public final class ImmediateModeRecorder {
             final AttribReader r = readers[positionReaderIndex];
             final int base = r.baseOffset + vertexIndex * r.stride;
             t.addVertex(
-                r.attrib.readComponent(r.data, base, 0),
-                r.attrib.readComponent(r.data, base, 1),
-                (r.size >= 3) ? r.attrib.readComponent(r.data, base, 2) : 0.0f);
+                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(
-                r.attrib.readComponent(r.data, base, 0),
-                r.attrib.readComponent(r.data, base, 1),
-                r.attrib.readComponent(r.data, base, 2));
+                readComponent(r, base, 0),
+                readComponent(r, base, 1),
+                readComponent(r, base, 2));
         } else if (r.loc == LOC_UV0) {
             t.setTextureUV(
-                r.attrib.readComponent(r.data, base, 0),
-                (r.size >= 2) ? r.attrib.readComponent(r.data, base, 1) : 0.0f);
+                readComponent(r, base, 0),
+                (r.size >= 2) ? readComponent(r, base, 1) : 0.0f);
         } else if (r.loc == LOC_UV1) {
-            if (r.attrib.type == GL11.GL_SHORT) {
+            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.attrib.type == GL11.GL_FLOAT) {
+            } 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 = r.attrib.readComponent(r.data, base, 0);
-            final float cg = r.attrib.readComponent(r.data, base, 1);
-            final float cb = r.attrib.readComponent(r.data, base, 2);
-            final float ca = (r.size >= 4) ? r.attrib.readComponent(r.data, base, 3) : 1.0f;
+            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/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

@@ -1,6 +1,5 @@
 package com.gtnewhorizons.angelica.glsm.recording.commands;
 
-import com.github.bsideup.jabel.Desugar;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import org.jetbrains.annotations.NotNull;
 import org.joml.Matrix4f;
@@ -12,7 +11,6 @@ import java.nio.FloatBuffer;
  * Command: glMultMatrix(matrix)
  * Multiplies the current matrix by the specified matrix.
  */
-@Desugar
 public record MultMatrixCmd(Matrix4f matrix, FloatBuffer buffer) implements DisplayListCommand {
 
     /**

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 +1,669 @@
+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";
+
+    // 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("glBufferSubData")
+            .add("glMapBuffer")
+            .add("glUnmapBuffer")
+            .add("glGetBufferSubData")
+            .add("glGetBufferParameteri")
+            .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");
+        final var gl31 = RedirectMap.newMap()
+            .add("glDrawElementsInstanced")
+            .add("glDrawArraysInstanced");
+        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");
+
+        // 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);
+
+        // 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")
+        );
+
+        // 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;
+        }
+    }
+}