Add a second profiles button to Angelica

* Add missing glMapBuffer overload
* Keep track of bound pixel buffer and suspend when needed

.gitignore

@@ -4,7 +4,7 @@
 /.vs/
 /.vscode/
 /run/
-/build/
+build/
 /eclipse/
 .classpath
 .project

README.MD

@@ -12,6 +12,14 @@
    * Complementary + Euphoria Patches is the primary compatibility target
    * Sildurs, Seus, and any other shaders might work
 
+## Core Profile
+Targets GL 3.3+ core profile
+* FFP emulation via generated GLSL shaders
+* Display list emulation
+* Software matrix stacks and state management through GLSM
+* GL_QUADS → GL_TRIANGLES conversion
+* Automatic transformation of mod shaders that use compat-only GLSL builtins (`gl_ModelViewMatrix`, `texture2D`, etc.)
+
 
 # Required Dependencies
 * [UniMixins](https://github.com/LegacyModdingMC/UniMixins/releases) >= 0.1.23
@@ -56,9 +64,9 @@
   * The [Iris](https://github.com/IrisShaders/Iris) Team: coderbot, IMS212, Justsnoopy30, FoundationGames
   * Asek3 for the Iris Forge port [Oculus](https://github.com/Asek3/Oculus/tree/839ce8eca8cf0c4f6b7a1322b906e5c99125ca69)
   * Backported code under the LGPL
-* Sodium
+* Sodium / Celeritas
   * JellySquid & the CaffeineMC team, for making Sodium in the first place
-  * Embeddedt for [Embeddium](https://github.com/embeddedt/embeddium/tree/dc59ca357c25beefd6288f0d1d40b4cd8e670ab8) under the [LGPL 3.0](https://github.com/embeddedt/embeddium/blob/16.x/forge/LICENSE)
+  * Embeddedt for Celeritas used under the LGPL 3.0
 * Reese's Sodium Options
   * FlashyReese for [Reese's Sodium Options](https://github.com/FlashyReese/reeses-sodium-options/tree/aa4ea67047cf53e54976e93c6bb1ab5ba16b142b) under the [MIT license](https://github.com/FlashyReese/reeses-sodium-options/blob/aa4ea67047cf53e54976e93c6bb1ab5ba16b142b/LICENSE.txt)
 * Neodymium
@@ -85,3 +93,8 @@
   * FalsePattern for [FalseTweaks](https://github.com/falsepattern/falsetweaks) - Item Rendering Optimizations taken from FalseTweaks under the LGPL 3.0 license
 * Beddium
   * Venn and Falsepattern for [Beddium](https://github.com/vfx-dev/Beddium) - MinimapRenderer, SafeChunkTracker, and some debug commands adapted under the LGPL 3.0 License
+* [Mesa](https://gitlab.freedesktop.org/mesa/mesa) — Code ported and/or inspired from Mesa - under the MIT licensed
+  * Display list ID allocator ported from [util_idalloc](https://gitlab.freedesktop.org/mesa/mesa/-/blob/main/src/util/u_idalloc.c) (Copyright 2017 Valve Corporation)
+  * FFP vertex shader generation inspired by ffvertex_prog.c (Copyright 2007 VMware, Inc.)
+  * FFP fragment shader generation inspired by ff_fragment_shader.c (Copyright 2007, 2009 VMware, Inc. / 2010-2011 Intel Corporation)
+  * Fog parameter optimization inspired by st_nir_lower_fog.c (Copyright 2023 Google LLC) and prog_statevars.c (Copyright 1999-2007 Brian Paul)

build.gradle.kts

@@ -1,3 +1,5 @@
+import xyz.wagyourtail.jvmdg.gradle.task.files.DowngradeFiles
+
 plugins {
     id("com.gtnewhorizons.gtnhconvention")
 }
@@ -5,6 +7,9 @@ plugins {
 minecraft {
     extraRunJvmArguments.add("-Dangelica.enableTestBlocks=true")
     extraRunJvmArguments.add("-Dangelica.dumpClass=true")
+//     extraRunJvmArguments.add("-Dangelica.useVulkan=true")
+//     extraRunJvmArguments.add("-Dangelica.vulkanDebug=true")
+//    extraRunJvmArguments.add("-Dorg.lwjgl.util.Debug=true")
 //    extraRunJvmArguments.addAll("-Dlegacy.debugClassLoadingSave=true")
 //    extraRunJvmArguments.addAll("-Drfb.dumpLoadedClasses=true", "-Drfb.dumpLoadedClassesPerTransformer=true")
     //extraRunJvmArguments.add("-Dangelica.redirectorLogspam=true")
@@ -16,8 +21,7 @@ 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) {
@@ -44,10 +48,49 @@ tasks.register<Copy>("copyDependencies") {
 }
 
 val embedOnly: Configuration by configurations
+val shadowImplementation: Configuration by configurations
 
-tasks.shadowJar {
-    from(embedOnly.map(::zipTree))
-    relocate("com.mitchej123", "com.mitchej123")
-    relocate("org.embeddedt", "org.embeddedt")
+val downgradeEmbedOnlyForTest by tasks.registering(DowngradeFiles::class) {
+    inputCollection = embedOnly
+}
+
+val stripModuleInfoFromShadow by tasks.registering(Jar::class) {
+    dependsOn(shadowImplementation)
+    from(shadowImplementation.map(::zipTree))
+    exclude("module-info.class")
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+    archiveClassifier = "shadow-stripped"
+}
+
+val downgradeShadowImplForTest by tasks.registering(DowngradeFiles::class) {
+    inputCollection = files(stripModuleInfoFromShadow.map { it.archiveFile })
+    outputs.dir(temporaryDir)
+}
+
+tasks.test {
+    dependsOn(downgradeEmbedOnlyForTest, downgradeShadowImplForTest)
+    classpath = classpath
+        .minus(embedOnly)
+        .plus(files(downgradeEmbedOnlyForTest.map { it.outputCollection }))
+        .minus(shadowImplementation)
+        .plus(files({ fileTree(downgradeShadowImplForTest.get().temporaryDir) }))
+}
+
+tasks.shadowJar {
+    dependsOn(embedOnly)
+    from(embedOnly.map(::zipTree))
+
+    duplicatesStrategy = DuplicatesStrategy.INCLUDE
+    mergeServiceFiles()
+
+    minimize {
+        exclude(project(":glsm"))
+        exclude(project(":lwjgl3-backend"))
+    }
+
+    relocate("com.mitchej123", "com.mitchej123")
+    relocate("org.embeddedt", "org.embeddedt")
+    relocate("com.gtnewhorizons.angelica.glsm", "com.gtnewhorizons.angelica.glsm")
+    relocate("com.gtnewhorizons.angelica.lwjgl3", "com.gtnewhorizons.angelica.lwjgl3")
 }
 

dependencies.gradle

@@ -47,12 +47,16 @@ 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
     embedOnly.canBeResolved = true
     compileClasspath.extendsFrom(embedOnly)
     testCompileClasspath.extendsFrom(embedOnly)
+    testRuntimeClasspath.extendsFrom(embedOnly)
+
 }
 
 
@@ -65,23 +69,29 @@ dependencies {
     compileOnly("com.github.GTNewHorizons:Hodgepodge:2.7.14:dev")
 
     compileOnly("com.gtnewhorizons.retrofuturabootstrap:RetroFuturaBootstrap:1.0.7") { 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:0.9.0:dev")
+    api("com.github.GTNewHorizons:GTNHLib:0.9.36: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:0.2.0-25.g3a943bb") {
+    shadowImplementation("org.taumc:glsl-transformation-lib:0.2.0-26.g5ee7d96-GTNH") {
         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:2.5.4-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')
@@ -107,24 +117,24 @@ dependencies {
 
     compileOnly("curse.maven:minefactory-reloaded-66672:2277486")
 
-    compileOnly("com.github.GTNewHorizons:NotEnoughIds:2.1.10:dev") // Mixin Version
-    compileOnly("com.github.GTNewHorizons:NotEnoughIds-Legacy:1.4.7:dev") // ASM Version
+    compileOnly("com.github.GTNewHorizons:NotEnoughIds:2.1.10:dev")
 
-    compileOnly(rfg.deobf("curse.maven:ntm-space-1121235:6974420"))
+    compileOnly(rfg.deobf("maven.modrinth:ntmspace:X5593_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"))
 
-//    runtimeOnlyNonPublishable("com.github.GTNewHorizons:CoreTweaks:0.3.3.6-GTNH")
-    // For testing alternative splash screens, can be sourced from https://github.com/MalTeeez/ModernSplash/releases
-    //runtimeOnly(rfg.deobf(files("dependencies/modernsplash-1.7.10-1.2.2-dev.jar")))
+    // For testing alternative splash screens — https://github.com/MalTeeez/ModernSplash/releases
+    // devOnlyNonPublishable("com.github.MalTeeez:modernsplash:1.7.10-1.2.4:dev")
 
     // Hodgepodge
     transformedMod("net.industrial-craft:industrialcraft-2:2.2.828-experimental:dev")
 
     // Better Crashes
-    compileOnly("com.github.GTNewHorizons:BetterCrashes:1.4.0-GTNH:dev")
+    compileOnly("com.github.GTNewHorizons:BetterCrashes:1.4.1-GTNH:dev")
 
     afterEvaluate {
         dependencies {

glsm/build.gradle.kts

@@ -0,0 +1,192 @@
+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()
+}
+
+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:9.7")
+
+    // 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")}")
+
+    // Test
+    testImplementation(sourceSets["stubs"].output)
+    testImplementation(platform("org.junit:junit-bom:${property("junitBomVersion")}"))
+    testImplementation("org.junit.jupiter:junit-jupiter")
+    testImplementation("org.lwjgl.lwjgl:lwjgl:${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())
+}
+
+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
+    dependsOn(tasks.named("testClasses"))
+}
+
+tasks.test {
+    useJUnitPlatform()
+
+    javaLauncher = javaToolchains.launcherFor {
+        languageVersion = JavaLanguageVersion.of(8)
+    }
+
+    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 }}")
+}
+
+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 +1,14 @@
+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 = 0.9.36
+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/CommandBufferBuilder.java

@@ -0,0 +1,67 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.recording.AccumulatedDraw;
+import com.gtnewhorizons.angelica.glsm.recording.CommandBuffer;
+import com.gtnewhorizons.angelica.glsm.recording.CommandBufferProcessor;
+
+import java.util.List;
+
+/**
+ * Builds final command buffers from raw command buffers and compiled VBO data.
+ * Bridges the gap between VBO compilation (glsm types) and buffer processing (recording types).
+ */
+public final class CommandBufferBuilder {
+
+    private CommandBufferBuilder() {}
+
+    /**
+     * Build commands with transform collapsing optimization.
+     * Accumulates MODELVIEW transforms and emits MultMatrix at barriers (draws, CallList).
+     * Uses mergedRanges where consecutive same-transform draws are combined.
+     */
+    public static void buildFromRawBuffer(
+            CommandBuffer rawBuffer,
+            List<AccumulatedDraw> accumulatedDraws,
+            CommandBuffer finalBuffer) {
+
+        rawBuffer.resetRead();
+        int cmdIndex = 0;
+        int rangeIndex = 0;
+
+        AccumulatedDraw draw;
+        while (rawBuffer.hasRemaining()) {
+            // Read and process the command
+            CommandBufferProcessor.copyCommand(rawBuffer, finalBuffer);
+
+            // Emit draw ranges at this command position
+            while (rangeIndex < accumulatedDraws.size() && (draw = accumulatedDraws.get(rangeIndex)).commandIndex == cmdIndex) {
+                emitDrawRangeToBuffer(draw, finalBuffer, rangeIndex);
+                rangeIndex++;
+            }
+
+            cmdIndex++;
+        }
+
+        while (rangeIndex < accumulatedDraws.size()) {
+            emitDrawRangeToBuffer(accumulatedDraws.get(rangeIndex), finalBuffer, rangeIndex);
+            rangeIndex++;
+        }
+    }
+
+    /**
+     * Emit a draw range to the output buffer, with transform if needed.
+     */
+    private static void emitDrawRangeToBuffer(
+            AccumulatedDraw draw,
+            CommandBuffer out,
+            int vboIdx) {
+
+        if (draw.restoreData != null) {
+            out.writeDrawRangeRestore(vboIdx, draw.restoreData);
+            return;
+        }
+
+        // Write the draw range command
+        out.writeDrawRange(vboIdx);
+    }
+}

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

@@ -0,0 +1,452 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.backend.RenderBackend;
+import org.taumc.glsl.ShaderParser;
+import org.taumc.glsl.Transformer;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * Compat transformation for mod shaders running under core profile.
+ *
+ * <p>Handles:
+ * <ul>
+ *   <li>Matrix builtin replacement (gl_ModelViewMatrix, gl_ProjectionMatrix, etc.)</li>
+ *   <li>Vertex attribute replacement (gl_Vertex, gl_Color, gl_MultiTexCoord0/1, gl_Normal)</li>
+ *   <li>gl_TexCoord[N] varying array → per-index in/out declarations</li>
+ *   <li>Texture function renames (texture2D → texture, etc.)</li>
+ *   <li>Fragment output handling (gl_FragColor → layout-qualified out declarations)</li>
+ *   <li>Fog builtins (gl_Fog, gl_FogFragCoord)</li>
+ *   <li>gl_FrontColor → local variable in vertex shaders</li>
+ *   <li>shadow2D/shadow2DLod → texture/textureLod with vec4 wrapping</li>
+ *   <li>Version upgrade to 330 core minimum</li>
+ *   <li>Reserved word pre-parse renaming (texture-as-variable, sample, etc.)</li>
+ * </ul>
+ */
+public class CompatShaderTransformer {
+
+    private static final Pattern VERSION_PATTERN = Pattern.compile("#version[ \\t]+(\\d+)(?:[ \\t]+(\\w+))?");
+
+    private static final Pattern DEFINE_PATTERN = Pattern.compile("^\\s*#\\s*define\\s+.+$", Pattern.MULTILINE);
+
+    /** Compat builtins that trigger AST transformation. */
+    private static final Set<String> COMPAT_BUILTINS = Set.of(
+        "gl_ModelView", "gl_Projection", "gl_NormalMatrix", "gl_TextureMatrix",
+        "gl_FragColor", "gl_Fog", "gl_FrontColor", "gl_Color",
+        "gl_Vertex", "gl_MultiTexCoord", "gl_TexCoord", "gl_Normal", "ftransform",
+        "texture2D", "texture3D", "texelFetch2D", "texelFetch3D", "textureSize2D",
+        "shadow2D", "gl_FrontLightModelProduct",
+        "gl_LightSource", "gl_FrontMaterial"
+    );
+
+    private static final Pattern NEEDS_TRANSFORM_PATTERN = Pattern.compile(
+        String.join("|", COMPAT_BUILTINS) + "|\\b(?:attribute|varying)\\b"
+    );
+
+    private static final Map<String, String> MATRIX_RENAMES = Map.of(
+        "gl_ModelViewMatrix", "angelica_ModelViewMatrix",
+        "gl_ModelViewMatrixInverse", "angelica_ModelViewMatrixInverse",
+        "gl_ProjectionMatrix", "angelica_ProjectionMatrix",
+        "gl_ProjectionMatrixInverse", "angelica_ProjectionMatrixInverse",
+        "gl_NormalMatrix", "angelica_NormalMatrix"
+    );
+
+    private static final Path DUMP_DIR;
+    private static final AtomicInteger dumpCounter = new AtomicInteger(0);
+
+    static {
+        DUMP_DIR = Boolean.parseBoolean(System.getProperty("angelica.dumpShaders", "false")) ? Paths.get("compat_shaders") : null;
+    }
+
+    private static final int CACHE_SIZE = 32;
+    private record CacheKey(String source, boolean isFragment) {}
+    private static final Map<CacheKey, String> cache = Collections.synchronizedMap(
+        new LinkedHashMap<>(32, 0.75f, true) {
+            @Override protected boolean removeEldestEntry(Map.Entry<CacheKey, String> eldest) {
+            return size() > CACHE_SIZE;
+        }
+    });
+
+    public static void clearCache() {
+        cache.clear();
+    }
+
+    /**
+     * Transform a mod shader source for core profile compatibility.
+     */
+    public static String transform(String source, boolean isFragment) {
+        final boolean needsTransform = needsTransformation(source);
+        String result;
+        if (!needsTransform) {
+            result = fixupVersion(source);
+        } else {
+            final CacheKey key = new CacheKey(source, isFragment);
+            final String cached = cache.get(key);
+            if (cached != null) {
+                dumpShader(source, cached, isFragment, needsTransform);
+                return cached;
+            }
+
+            try {
+                result = transformInternal(source, isFragment);
+                cache.put(key, result);
+            } catch (Exception e) {
+                GLStateManager.LOGGER.warn("CompatShaderTransformer: AST transformation failed, falling back to version fixup only", e);
+                result = fixupVersion(source);
+            }
+        }
+
+        dumpShader(source, result, isFragment, needsTransform);
+        return result;
+    }
+
+    private static boolean needsTransformation(String source) {
+        // Shaders already at 330+ core don't need compat transformation
+        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 NEEDS_TRANSFORM_PATTERN.matcher(source).find();
+    }
+
+    private static String transformInternal(String source, boolean isFragment) {
+        final Matcher versionMatcher = VERSION_PATTERN.matcher(source);
+        int declaredVersion = 110;
+        if (versionMatcher.find()) {
+            declaredVersion = Integer.parseInt(versionMatcher.group(1));
+        }
+
+        final int targetVersion = Math.max(declaredVersion, RENDER_BACKEND != null ? RENDER_BACKEND.getMinGLSLVersion() : 330);
+
+        // Pre-parse reserved word renaming — prevents ANTLR parse failures
+        source = GlslTransformUtils.replaceTexture(source);
+        source = GlslTransformUtils.renameReservedWords(source, targetVersion);
+
+        final ShaderParser.ParsedShader parsedShader = ShaderParser.parseShader(source);
+        final Transformer transformer = new Transformer(parsedShader.full());
+
+        injectMatrixUniforms(transformer);
+
+        transformFog(transformer, isFragment, source);
+
+        // gl_FrontLightModelProduct.sceneColor → angelica_SceneColor uniform
+        if (source.contains("gl_FrontLightModelProduct")) {
+            transformer.injectVariable("uniform vec4 angelica_SceneColor;");
+            transformer.replaceExpression("gl_FrontLightModelProduct.sceneColor", "angelica_SceneColor");
+        }
+
+        // gl_LightSource[i] → struct + uniform array (both via injectFunction to keep struct before uniform)
+        if (source.contains("gl_LightSource")) {
+            transformer.injectFunction("struct angelica_LightSourceParameters {"
+                    + "vec4 ambient;vec4 diffuse;vec4 specular;vec4 position;vec4 halfVector;"
+                    + "vec3 spotDirection;float spotExponent;float spotCutoff;float spotCosCutoff;"
+                    + "float constantAttenuation;float linearAttenuation;float quadraticAttenuation;"
+                    + "};");
+            transformer.injectFunction("uniform angelica_LightSourceParameters angelica_LightSource[2];");
+            transformer.rename("gl_LightSource", "angelica_LightSource");
+        }
+
+        // gl_FrontMaterial → struct + uniform (both via injectFunction to keep struct before uniform)
+        if (source.contains("gl_FrontMaterial")) {
+            transformer.injectFunction("struct angelica_MaterialParameters {"
+                    + "vec4 emission;vec4 ambient;vec4 diffuse;vec4 specular;float shininess;"
+                    + "};");
+            transformer.injectFunction("uniform angelica_MaterialParameters angelica_FrontMaterial;");
+            transformer.rename("gl_FrontMaterial", "angelica_FrontMaterial");
+        }
+
+        // gl_FrontColor (vertex) → gl_Color (fragment) varying chain
+        // Vertex side is unconditional: fragment may read gl_Color without vertex writing gl_FrontColor.
+        // Uses angelica_ prefix to avoid colliding with user-declared varyings (e.g. "v_Color").
+        if (!isFragment) {
+            transformer.injectVariable("out vec4 angelica_FrontColor;");
+            transformer.rename("gl_FrontColor", "angelica_FrontColor");
+            transformer.prependMain("angelica_FrontColor = vec4(1.0);");
+
+            // Vertex attributes — replaces removed FFP vertex inputs with explicit in declarations
+            transformVertexAttributes(transformer, source);
+        } else {
+            if (source.contains("gl_Color")) {
+                transformer.injectVariable("in vec4 angelica_FrontColor;");
+                transformer.rename("gl_Color", "angelica_FrontColor");
+            }
+        }
+
+        // gl_TexCoord[N] varying array → per-index in/out declarations
+        final Set<Integer> texCoordIndices = new HashSet<>();
+        transformer.renameArray("gl_TexCoord", "angelica_TexCoord", texCoordIndices);
+        for (Integer i : texCoordIndices) {
+            final String qualifier = isFragment ? "in" : "out";
+            transformer.injectVariable(qualifier + " vec4 angelica_TexCoord" + i + ";");
+        }
+
+        // Fragment output handling + alpha test discard
+        if (isFragment) {
+            transformFragmentOutputs(transformer);
+        }
+
+        // texture-as-variable collision handling
+        if (transformer.containsCall("texture") && transformer.hasVariable("texture")) {
+            transformer.rename("texture", "gtexture");
+        }
+        if (transformer.hasVariable("angelica_renamed_texture")) {
+            transformer.rename("angelica_renamed_texture", "gtexture");
+        }
+
+        transformer.renameFunctionCall(GlslTransformUtils.TEXTURE_RENAMES);
+
+        transformer.renameAndWrapShadow("shadow2D", "texture");
+        transformer.renameAndWrapShadow("shadow2DLod", "textureLod");
+
+        final String versionDirective = "#version " + targetVersion + " core\n";
+        final String extensions = VERSION_PATTERN.matcher(GlslTransformUtils.getFormattedShader(parsedShader.pre(), "")).replaceFirst("").trim();
+
+        // Preserve #define directives
+        final StringBuilder defines = new StringBuilder();
+        final Matcher defineMatcher = DEFINE_PATTERN.matcher(source);
+        while (defineMatcher.find()) {
+            defines.append(defineMatcher.group().trim()).append('\n');
+        }
+
+        final String header = versionDirective + (extensions.isEmpty() ? "" : "\n" + extensions) + (defines.isEmpty() ? "" : "\n" + defines);
+        final StringBuilder result = new StringBuilder();
+        transformer.mutateTree(tree -> result.append(GlslTransformUtils.getFormattedShader(tree, header)));
+
+        // Restore pre-parse renames
+        String output = GlslTransformUtils.restoreReservedWords(result.toString());
+
+        // Core profile: attribute → in, varying → out (vertex) / in (fragment)
+        output = fixupQualifiers(output, isFragment);
+
+        return output;
+    }
+
+    /**
+     * Inject matrix uniforms and rename compat builtins.
+     */
+    private static void injectMatrixUniforms(Transformer transformer) {
+        transformer.injectVariable("uniform mat4 angelica_ModelViewMatrix;");
+        transformer.injectVariable("uniform mat4 angelica_ModelViewMatrixInverse;");
+        transformer.injectVariable("uniform mat4 angelica_ProjectionMatrix;");
+        transformer.injectVariable("uniform mat4 angelica_ProjectionMatrixInverse;");
+        transformer.injectVariable("uniform mat3 angelica_NormalMatrix;");
+        transformer.injectVariable("uniform mat4 angelica_LightmapTextureMatrix;");
+
+        transformer.rename(MATRIX_RENAMES);
+
+        // Expression replacements
+        transformer.replaceExpression("gl_ModelViewProjectionMatrix", "(angelica_ProjectionMatrix * angelica_ModelViewMatrix)");
+        transformer.replaceExpression("gl_TextureMatrix[0]", "mat4(1.0)");
+        transformer.replaceExpression("gl_TextureMatrix[1]", "angelica_LightmapTextureMatrix");
+        transformer.replaceExpression(
+                "gl_TextureMatrix",
+                "mat4[8](mat4(1.0), angelica_LightmapTextureMatrix, mat4(1.0), mat4(1.0), mat4(1.0), mat4(1.0), mat4(1.0), mat4(1.0))");
+    }
+
+    /**
+     * Transform fragment outputs for core profile.
+     */
+    private static void transformFragmentOutputs(Transformer transformer) {
+        if (transformer.containsCall("gl_FragColor")) {
+            transformer.replaceExpression("gl_FragColor", "gl_FragData[0]");
+        }
+
+        final Set<Integer> found = new HashSet<>();
+        transformer.renameArray("gl_FragData", "angelica_FragData", found);
+
+        for (Integer i : found) {
+            transformer.injectVariable("layout (location = " + i + ") out vec4 angelica_FragData" + i + ";");
+        }
+
+        // Core profile: GL_ALPHA_TEST is removed - inject runtime discard using GLSM-tracked alpha reference (uploaded by CompatUniformManager).
+        if (found.contains(0)) {
+            transformer.injectVariable("uniform float angelica_currentAlphaTest;");
+            transformer.appendMain("if (angelica_FragData0.a <= angelica_currentAlphaTest) discard;");
+        }
+    }
+
+    private static void transformFog(Transformer transformer, boolean isFragment, String source) {
+        // Vertex side is unconditional: fragment may read gl_FogFragCoord without vertex writing it
+        transformer.rename("gl_FogFragCoord", "angelica_FogFragCoord");
+        if (!isFragment) {
+            transformer.injectVariable("out float angelica_FogFragCoord;");
+            transformer.prependMain("angelica_FogFragCoord = 0.0;");
+        } else {
+            if (source.contains("gl_FogFragCoord")) {
+                transformer.injectVariable("in float angelica_FogFragCoord;");
+            }
+        }
+
+        transformer.rename("gl_Fog", "angelica_Fog");
+        transformer.injectVariable("uniform float angelica_FogDensity;");
+        transformer.injectVariable("uniform float angelica_FogStart;");
+        transformer.injectVariable("uniform float angelica_FogEnd;");
+        transformer.injectVariable("uniform vec4 angelica_FogColor;");
+        transformer.injectFunction("struct angelica_FogParameters {vec4 color;float density;float start;float end;float scale;};");
+        transformer.injectFunction("angelica_FogParameters angelica_Fog = angelica_FogParameters("
+                + "angelica_FogColor, angelica_FogDensity, angelica_FogStart, angelica_FogEnd, "
+                + "1.0 / (angelica_FogEnd - angelica_FogStart));");
+    }
+
+    /**
+     * Replace removed FFP vertex attributes with explicit {@code in} declarations at core profile attribute locations.
+     */
+    private static void transformVertexAttributes(Transformer transformer, String source) {
+        if (source.contains("gl_Vertex") || source.contains("ftransform")) {
+            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")) {
+            transformer.injectVariable("layout(location = 1) in vec4 angelica_Color;");
+            transformer.rename("gl_Color", "angelica_Color");
+        }
+        if (source.contains("gl_MultiTexCoord0")) {
+            transformer.injectVariable("layout(location = 2) in vec4 angelica_MultiTexCoord0;");
+            transformer.rename("gl_MultiTexCoord0", "angelica_MultiTexCoord0");
+        }
+        if (source.contains("gl_MultiTexCoord1")) {
+            transformer.injectVariable("layout(location = 3) in vec4 angelica_MultiTexCoord1;");
+            transformer.rename("gl_MultiTexCoord1", "angelica_MultiTexCoord1");
+        }
+        if (source.contains("gl_Normal")) {
+            transformer.injectVariable("layout(location = 4) in vec3 angelica_Normal;");
+            transformer.rename("gl_Normal", "angelica_Normal");
+        }
+        if (source.contains("ftransform")) {
+            transformer.replaceExpression("ftransform()", "(angelica_ProjectionMatrix * angelica_ModelViewMatrix * angelica_Vertex)");
+        }
+    }
+
+    private static void dumpShader(String original, String transformed, boolean isFragment, boolean wasTransformed) {
+        if (DUMP_DIR == null) return;
+        final int id = dumpCounter.getAndIncrement();
+        final String suffix = isFragment ? ".frag.glsl" : ".vert.glsl";
+        try {
+            Files.createDirectories(DUMP_DIR);
+            // Capture caller info for identification
+            final String caller = identifyCaller();
+            final String header = "// Compat shader dump #" + id + " (" + (isFragment ? "fragment" : "vertex") + ")"
+                + "\n// Transformed: " + wasTransformed
+                + "\n// Caller: " + caller + "\n\n";
+            Files.writeString(DUMP_DIR.resolve(id + "_original" + suffix), header + original, StandardCharsets.UTF_8);
+            Files.writeString(DUMP_DIR.resolve(id + "_transformed" + suffix), header + transformed, StandardCharsets.UTF_8);
+        } catch (IOException e) {
+            GLStateManager.LOGGER.warn("Failed to dump compat shader: {}", e.getMessage());
+        }
+    }
+
+    private static String identifyCaller() {
+        for (StackTraceElement frame : Thread.currentThread().getStackTrace()) {
+            final String cls = frame.getClassName();
+            if (!cls.startsWith("com.gtnewhorizons.angelica.glsm.")
+                && !cls.startsWith("java.")
+                && !cls.equals("org.lwjgl.opengl.GL20")) {
+                return cls + "." + frame.getMethodName() + ":" + frame.getLineNumber();
+            }
+        }
+        return "unknown";
+    }
+
+    private static final Pattern ATTRIBUTE_PATTERN = Pattern.compile("\\battribute\\b");
+    private static final Pattern VARYING_PATTERN = Pattern.compile("\\bvarying\\b");
+
+    /** Replace legacy storage qualifiers removed in core profile. Safe on AST-serialized output (no comments). */
+    public static String fixupQualifiers(String source, boolean isFragment) {
+        source = ATTRIBUTE_PATTERN.matcher(source).replaceAll("in");
+        source = VARYING_PATTERN.matcher(source).replaceAll(isFragment ? "in" : "out");
+        return source;
+    }
+
+    // Patterns for parsing fragment shader in declarations to generate passthrough vertex shaders
+    private static final Pattern FRAG_IN_COLOR = Pattern.compile("\\bin\\s+vec4\\s+angelica_FrontColor\\b");
+    private static final Pattern FRAG_IN_TEXCOORD = Pattern.compile("\\bin\\s+vec4\\s+angelica_TexCoord(\\d+)\\b");
+    private static final Pattern FRAG_IN_FOGCOORD = Pattern.compile("\\bin\\s+float\\s+angelica_FogFragCoord\\b");
+
+    /**
+     * Generate a passthrough vertex shader for a fragment-only program.
+     *
+     * @param fragmentSource the transformed fragment shader source
+     * @return a complete vertex shader source string
+     */
+    public static String generatePassthroughVertexShader(String fragmentSource) {
+        final StringBuilder sb = new StringBuilder(512);
+        sb.append("#version 330 core\n\n");
+
+        // Always have position
+        sb.append("layout(location = 0) in vec4 a_Position;\n");
+
+        // Matrix uniforms for position transform
+        sb.append("uniform mat4 angelica_ModelViewMatrix;\n");
+        sb.append("uniform mat4 angelica_ProjectionMatrix;\n");
+
+        final StringBuilder varyings = new StringBuilder();
+        final StringBuilder assignments = new StringBuilder();
+        if (FRAG_IN_COLOR.matcher(fragmentSource).find()) {
+            sb.append("layout(location = 1) in vec4 a_Color;\n");
+            varyings.append("out vec4 angelica_FrontColor;\n");
+            assignments.append("  angelica_FrontColor = a_Color;\n");
+        }
+
+        final Matcher texCoordMatcher = FRAG_IN_TEXCOORD.matcher(fragmentSource);
+        final Set<Integer> texCoordIndices = new HashSet<>();
+        while (texCoordMatcher.find()) {
+            texCoordIndices.add(Integer.parseInt(texCoordMatcher.group(1)));
+        }
+        for (int i : texCoordIndices) {
+            // PRIMARY_UV=2, SECONDARY_UV=3. Only indices 0 and 1 are supported; higher indices collide at location 3.
+            final int location = i == 0 ? 2 : 3;
+            sb.append("layout(location = ").append(location).append(") in vec4 a_TexCoord").append(i).append(";\n");
+            varyings.append("out vec4 angelica_TexCoord").append(i).append(";\n");
+            assignments.append("  angelica_TexCoord").append(i).append(" = a_TexCoord").append(i).append(";\n");
+        }
+
+        if (FRAG_IN_FOGCOORD.matcher(fragmentSource).find()) {
+            varyings.append("out float angelica_FogFragCoord;\n");
+            assignments.append("  angelica_FogFragCoord = abs((angelica_ModelViewMatrix * a_Position).z);\n");
+        }
+
+        sb.append(varyings);
+        sb.append("\nvoid main() {\n");
+        sb.append("  gl_Position = angelica_ProjectionMatrix * angelica_ModelViewMatrix * a_Position;\n");
+        sb.append(assignments);
+        sb.append("}\n");
+
+        return sb.toString();
+    }
+
+    /** Ensure #version is at least 330 core, strip 'compatibility' profile. */
+    private static String fixupVersion(String source) {
+        final Matcher m = VERSION_PATTERN.matcher(source);
+        if (!m.find()) {
+            return "#version 330 core\n" + source;
+        }
+
+        final int version = Integer.parseInt(m.group(1));
+        final String profile = m.group(2);
+
+        if (version >= 330 && !"compatibility".equals(profile)) {
+            if ("core".equals(profile)) return source;
+            return m.replaceFirst("#version " + version + " core");
+        }
+
+        final int targetVersion = Math.max(version, 330);
+        return m.replaceFirst("#version " + targetVersion + " core");
+    }
+}

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

@@ -0,0 +1,406 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.stacks.FogStateStack;
+import com.gtnewhorizons.angelica.glsm.stacks.LightStateStack;
+import com.gtnewhorizons.angelica.glsm.states.ClipPlaneState;
+import com.gtnewhorizons.angelica.glsm.states.LightModelState;
+import com.gtnewhorizons.angelica.glsm.states.LightState;
+import com.gtnewhorizons.angelica.glsm.states.MaterialState;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.joml.Matrix3f;
+import org.joml.Matrix4f;
+import org.lwjgl.BufferUtils;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL20;
+
+import java.nio.FloatBuffer;
+
+/**
+ * Per-program compat uniform location cache and upload manager.
+ *
+ * <p>Manages {@code angelica_*} uniforms injected by {@link CompatShaderTransformer} and {@code iris_*} matrix uniforms used by Iris/celeritas shader
+ * programs.
+ */
+public class CompatUniformManager {
+
+    // Uniform location indices within the cached array (package-private for tests)
+    static final int LOC_MODELVIEW = 0;
+    static final int LOC_MODELVIEW_INVERSE = 1;
+    static final int LOC_PROJECTION = 2;
+    static final int LOC_PROJECTION_INVERSE = 3;
+    static final int LOC_NORMAL = 4;
+    static final int LOC_LIGHTMAP_TEXTURE_MATRIX = 5;
+    static final int LOC_FOG_DENSITY = 6;
+    static final int LOC_FOG_START = 7;
+    static final int LOC_FOG_END = 8;
+    static final int LOC_FOG_COLOR = 9;
+    static final int LOC_IRIS_MODELVIEW = 10;
+    static final int LOC_IRIS_PROJECTION = 11;
+    static final int LOC_IRIS_NORMAL = 12;
+    static final int LOC_IRIS_LIGHTMAP_TEXTURE_MATRIX = 13;
+    static final int LOC_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;
+
+    // Light source fields: 12 per light × 2 lights = 24 locations
+    static final int LIGHT_FIELDS = 12;
+    static final int LF_AMBIENT = 0, LF_DIFFUSE = 1, LF_SPECULAR = 2, LF_POSITION = 3;
+    static final int LF_HALF_VECTOR = 4, LF_SPOT_DIRECTION = 5, LF_SPOT_EXPONENT = 6;
+    static final int LF_SPOT_CUTOFF = 7, LF_SPOT_COS_CUTOFF = 8;
+    static final int LF_CONSTANT_ATTEN = 9, LF_LINEAR_ATTEN = 10, LF_QUADRATIC_ATTEN = 11;
+    static final int LOC_LIGHT_BASE = 18;
+
+    // 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_COUNT = LOC_MAT_BASE + MAT_FIELDS; // 47
+
+    private static final String[] LIGHT_FIELD_NAMES = {
+        "ambient", "diffuse", "specular", "position", "halfVector",
+        "spotDirection", "spotExponent", "spotCutoff", "spotCosCutoff",
+        "constantAttenuation", "linearAttenuation", "quadraticAttenuation",
+    };
+    private static final String[] MAT_FIELD_NAMES = {
+        "emission", "ambient", "diffuse", "specular", "shininess",
+    };
+
+    private static final String[] UNIFORM_NAMES;
+
+    static {
+        UNIFORM_NAMES = new String[LOC_COUNT];
+        UNIFORM_NAMES[LOC_MODELVIEW] = "angelica_ModelViewMatrix";
+        UNIFORM_NAMES[LOC_MODELVIEW_INVERSE] = "angelica_ModelViewMatrixInverse";
+        UNIFORM_NAMES[LOC_PROJECTION] = "angelica_ProjectionMatrix";
+        UNIFORM_NAMES[LOC_PROJECTION_INVERSE] = "angelica_ProjectionMatrixInverse";
+        UNIFORM_NAMES[LOC_NORMAL] = "angelica_NormalMatrix";
+        UNIFORM_NAMES[LOC_LIGHTMAP_TEXTURE_MATRIX] = "angelica_LightmapTextureMatrix";
+        UNIFORM_NAMES[LOC_FOG_DENSITY] = "angelica_FogDensity";
+        UNIFORM_NAMES[LOC_FOG_START] = "angelica_FogStart";
+        UNIFORM_NAMES[LOC_FOG_END] = "angelica_FogEnd";
+        UNIFORM_NAMES[LOC_FOG_COLOR] = "angelica_FogColor";
+        UNIFORM_NAMES[LOC_IRIS_MODELVIEW] = "iris_ModelViewMatrix";
+        UNIFORM_NAMES[LOC_IRIS_PROJECTION] = "iris_ProjectionMatrix";
+        UNIFORM_NAMES[LOC_IRIS_NORMAL] = "iris_NormalMatrix";
+        UNIFORM_NAMES[LOC_IRIS_LIGHTMAP_TEXTURE_MATRIX] = "iris_LightmapTextureMatrix";
+        UNIFORM_NAMES[LOC_ALPHA_TEST_REF] = "angelica_currentAlphaTest";
+        UNIFORM_NAMES[LOC_SCENE_COLOR] = "angelica_SceneColor";
+        UNIFORM_NAMES[LOC_CLIP_PLANES] = "angelica_ClipPlane[0]";
+        UNIFORM_NAMES[LOC_CLIP_PLANES_ENABLED] = "angelica_ClipPlanesEnabled";
+        for (int li = 0; li < 2; li++) {
+            for (int fi = 0; fi < LIGHT_FIELDS; fi++) {
+                UNIFORM_NAMES[LOC_LIGHT_BASE + li * LIGHT_FIELDS + fi] = "angelica_LightSource[" + li + "]." + LIGHT_FIELD_NAMES[fi];
+            }
+        }
+        for (int fi = 0; fi < MAT_FIELDS; fi++) {
+            UNIFORM_NAMES[LOC_MAT_BASE + fi] = "angelica_FrontMaterial." + MAT_FIELD_NAMES[fi];
+        }
+    }
+
+    /** Per-program cached uniform locations. Maps program ID → int[LOC_COUNT]. */
+    private static final Int2ObjectOpenHashMap<int[]> programLocations = new Int2ObjectOpenHashMap<>();
+
+    // Reusable NIO buffers for upload
+    private static final FloatBuffer mat4Buf = BufferUtils.createFloatBuffer(16);
+    private static final FloatBuffer mat3Buf = BufferUtils.createFloatBuffer(9);
+    private static final FloatBuffer vec4Buf = BufferUtils.createFloatBuffer(4);
+    private static final FloatBuffer clipPlaneBuf = BufferUtils.createFloatBuffer(32); // 8 planes * vec4
+    private static final Matrix3f normalMatrix = new Matrix3f();
+    private static final Matrix4f scratchMatrix = new Matrix4f();
+
+    private static final 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() {}
+
+    public static void onLinkProgram(int program) {
+        int[] locs = new int[LOC_COUNT];
+        boolean hasAny = false;
+
+        for (int i = 0; i < LOC_COUNT; i++) {
+            locs[i] = RENDER_BACKEND.getUniformLocation(program, UNIFORM_NAMES[i]);
+            if (locs[i] != -1) hasAny = true;
+        }
+
+        if (hasAny) {
+            programLocations.put(program, locs);
+            GLStateManager.LOGGER.debug("CompatUniformManager: program {} has compat uniforms", program);
+        }
+    }
+
+    public static void onUseProgram(int program) {
+        if (program == 0) return;
+
+        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
+        final int mvGen = GLStateManager.mvGeneration;
+        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;
+        if (mvChanged || projChanged || texMatChanged) {
+            uploadMatrices(locs, mvChanged, projChanged, texMatChanged);
+            lastMvGen = mvGen;
+            lastProjGen = projGen;
+            lastTexMatGen = texMatGen;
+        }
+
+        // Fragment-category uniforms (fog, alpha) — skip if generation unchanged
+        final int fragGen = GLStateManager.fragmentGeneration;
+        if (programChanged || fragGen != lastFragmentGen) {
+            lastFragmentGen = fragGen;
+            uploadFragmentUniforms(locs);
+        }
+
+        // Lighting-derived uniforms (scene color, light sources, material)
+        final int litGen = GLStateManager.lightingGeneration;
+        if (programChanged || litGen != lastLightingGen) {
+            lastLightingGen = litGen;
+            if (locs[LOC_SCENE_COLOR] != -1) uploadSceneColor(locs);
+            uploadLightSources(locs);
+            uploadMaterial(locs);
+        }
+
+        // Clip plane equations + enabled bool — uploaded when enable state or equations change
+        if (locs[LOC_CLIP_PLANES] != -1 || locs[LOC_CLIP_PLANES_ENABLED] != -1) {
+            final int cpGen = GLStateManager.clipPlaneGeneration;
+            if (programChanged || cpGen != lastClipPlaneGen) {
+                lastClipPlaneGen = cpGen;
+                uploadClipPlanes(locs);
+            }
+        }
+    }
+
+    private static void uploadMatrices(int[] locs, boolean mvChanged, boolean projChanged, boolean texMatChanged) {
+        final Matrix4f mv = GLStateManager.getModelViewMatrix();
+        final Matrix4f proj = GLStateManager.getProjectionMatrix();
+
+        if (mvChanged) {
+            // ModelView
+            if (locs[LOC_MODELVIEW] != -1 || locs[LOC_IRIS_MODELVIEW] != -1) {
+                mv.get(mat4Buf);
+                if (locs[LOC_MODELVIEW] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_MODELVIEW], false, mat4Buf);
+                }
+                if (locs[LOC_IRIS_MODELVIEW] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_MODELVIEW], false, mat4Buf);
+                }
+            }
+
+            // ModelView Inverse
+            if (locs[LOC_MODELVIEW_INVERSE] != -1) {
+                mv.invert(scratchMatrix);
+                scratchMatrix.get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(locs[LOC_MODELVIEW_INVERSE], false, mat4Buf);
+            }
+
+            // 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) {
+                    RENDER_BACKEND.uniformMatrix3(locs[LOC_NORMAL], false, mat3Buf);
+                }
+                if (locs[LOC_IRIS_NORMAL] != -1) {
+                    RENDER_BACKEND.uniformMatrix3(locs[LOC_IRIS_NORMAL], false, mat3Buf);
+                }
+            }
+        }
+
+        if (projChanged) {
+            // Projection
+            if (locs[LOC_PROJECTION] != -1 || locs[LOC_IRIS_PROJECTION] != -1) {
+                proj.get(mat4Buf);
+                if (locs[LOC_PROJECTION] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_PROJECTION], false, mat4Buf);
+                }
+                if (locs[LOC_IRIS_PROJECTION] != -1) {
+                    RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_PROJECTION], false, mat4Buf);
+                }
+            }
+
+            // Projection Inverse
+            if (locs[LOC_PROJECTION_INVERSE] != -1) {
+                proj.invert(scratchMatrix);
+                scratchMatrix.get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(locs[LOC_PROJECTION_INVERSE], false, mat4Buf);
+            }
+        }
+
+        if (texMatChanged) {
+            // Iris lightmap texture matrix (constant)
+            if (locs[LOC_IRIS_LIGHTMAP_TEXTURE_MATRIX] != -1) {
+                RENDER_BACKEND.uniformMatrix4(locs[LOC_IRIS_LIGHTMAP_TEXTURE_MATRIX], false, lightmapMatrixBuf);
+            }
+
+            // angelica_LightmapTextureMatrix — actual GLSM texture unit 1 matrix (set by enableLightmap())
+            if (locs[LOC_LIGHTMAP_TEXTURE_MATRIX] != -1) {
+                GLStateManager.getTextures().getTextureUnitMatrix(1).get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(locs[LOC_LIGHTMAP_TEXTURE_MATRIX], false, mat4Buf);
+            }
+        }
+    }
+
+    private static void uploadFragmentUniforms(int[] locs) {
+        // Fog uniforms
+        FogStateStack fog = GLStateManager.getFogState();
+        if (locs[LOC_FOG_DENSITY] != -1) {
+            RENDER_BACKEND.uniform1f(locs[LOC_FOG_DENSITY], Math.max(0.0f, fog.getDensity()));
+        }
+        if (locs[LOC_FOG_START] != -1) {
+            RENDER_BACKEND.uniform1f(locs[LOC_FOG_START], fog.getStart());
+        }
+        if (locs[LOC_FOG_END] != -1) {
+            RENDER_BACKEND.uniform1f(locs[LOC_FOG_END], fog.getEnd());
+        }
+        if (locs[LOC_FOG_COLOR] != -1) {
+            vec4Buf.clear();
+            vec4Buf.put((float) fog.getFogColor().x).put((float) fog.getFogColor().y).put((float) fog.getFogColor().z).put(fog.getFogAlpha());
+            vec4Buf.flip();
+            RENDER_BACKEND.uniform4(locs[LOC_FOG_COLOR], vec4Buf);
+        }
+
+        // Alpha test reference — core profile replacement for GL_ALPHA_TEST
+        // Return -1.0f for ALWAYS or disabled so `alpha <= ref` never discards.
+        if (locs[LOC_ALPHA_TEST_REF] != -1) {
+            final float ref;
+            if (!GLStateManager.getAlphaTest().isEnabled() || GLStateManager.getAlphaState().getFunction() == GL11.GL_ALWAYS) {
+                ref = -1.0f;
+            } else {
+                ref = GLStateManager.getAlphaState().getReference();
+            }
+            RENDER_BACKEND.uniform1f(locs[LOC_ALPHA_TEST_REF], ref);
+        }
+    }
+
+    /**
+     * Scene color = emission + ambient * lightModel.ambient, alpha = diffuse.a Same computation as {@code Uniforms.uploadLightingPreComputed()}.
+     */
+    private static void uploadSceneColor(int[] locs) {
+        final MaterialState mat = GLStateManager.getFrontMaterial();
+        final LightModelState lm = GLStateManager.getLightModel();
+        vec4Buf.clear();
+        vec4Buf.put(mat.emission.x + mat.ambient.x * lm.ambient.x)
+               .put(mat.emission.y + mat.ambient.y * lm.ambient.y)
+               .put(mat.emission.z + mat.ambient.z * lm.ambient.z)
+               .put(mat.diffuse.w);
+        vec4Buf.flip();
+        RENDER_BACKEND.uniform4(locs[LOC_SCENE_COLOR], vec4Buf);
+    }
+
+    private static void uploadLightSources(int[] locs) {
+        // Early exit: if the first light field isn't present, no lighting uniforms exist
+        if (locs[LOC_LIGHT_BASE] == -1) return;
+        final LightStateStack[] lights = GLStateManager.getLightDataStates();
+        for (int li = 0; li < 2; li++) {
+            final int base = LOC_LIGHT_BASE + li * LIGHT_FIELDS;
+            final LightState light = lights[li];
+
+            if (locs[base + LF_AMBIENT] != -1)
+                RENDER_BACKEND.uniform4f(locs[base + LF_AMBIENT], light.ambient.x, light.ambient.y, light.ambient.z, light.ambient.w);
+            if (locs[base + LF_DIFFUSE] != -1)
+                RENDER_BACKEND.uniform4f(locs[base + LF_DIFFUSE], light.diffuse.x, light.diffuse.y, light.diffuse.z, light.diffuse.w);
+            if (locs[base + LF_SPECULAR] != -1)
+                RENDER_BACKEND.uniform4f(locs[base + LF_SPECULAR], light.specular.x, light.specular.y, light.specular.z, light.specular.w);
+            if (locs[base + LF_POSITION] != -1)
+                RENDER_BACKEND.uniform4f(locs[base + LF_POSITION], light.position.x, light.position.y, light.position.z, light.position.w);
+            if (locs[base + LF_HALF_VECTOR] != -1) {
+                // halfVector = normalize(normalize(position.xyz) + eye), eye=(0,0,1) for infinite viewer
+                float hx, hy, hz;
+                if (light.position.w == 0.0f) {
+                    final float len = (float) Math.sqrt(light.position.x * light.position.x
+                            + light.position.y * light.position.y
+                            + light.position.z * light.position.z);
+                    if (len > 0) {
+                        hx = light.position.x / len;
+                        hy = light.position.y / len;
+                        hz = light.position.z / len + 1.0f;
+                    } else {
+                        hx = 0; hy = 0; hz = 1;
+                    }
+                } else {
+                    hx = 0; hy = 0; hz = 1;
+                }
+                final float hlen = (float) Math.sqrt(hx * hx + hy * hy + hz * hz);
+                if (hlen > 0) { hx /= hlen; hy /= hlen; hz /= hlen; }
+                RENDER_BACKEND.uniform4f(locs[base + LF_HALF_VECTOR], hx, hy, hz, 0.0f);
+            }
+            if (locs[base + LF_SPOT_DIRECTION] != -1) RENDER_BACKEND.uniform3f(locs[base + LF_SPOT_DIRECTION], light.spotDirection.x, light.spotDirection.y, light.spotDirection.z);
+            if (locs[base + LF_SPOT_EXPONENT] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_SPOT_EXPONENT], light.spotExponent);
+            if (locs[base + LF_SPOT_CUTOFF] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_SPOT_CUTOFF], light.spotCutoff);
+            if (locs[base + LF_SPOT_COS_CUTOFF] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_SPOT_COS_CUTOFF], light.spotCosCutoff);
+            if (locs[base + LF_CONSTANT_ATTEN] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_CONSTANT_ATTEN], light.constantAttenuation);
+            if (locs[base + LF_LINEAR_ATTEN] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_LINEAR_ATTEN], light.linearAttenuation);
+            if (locs[base + LF_QUADRATIC_ATTEN] != -1) RENDER_BACKEND.uniform1f(locs[base + LF_QUADRATIC_ATTEN], light.quadraticAttenuation);
+        }
+    }
+
+    private static void uploadMaterial(int[] locs) {
+        // Early exit: if the first material field isn't present, no material uniforms exist
+        if (locs[LOC_MAT_BASE] == -1) return;
+        final MaterialState mat = GLStateManager.getFrontMaterial();
+        if (locs[LOC_MAT_BASE + MF_EMISSION] != -1)
+            RENDER_BACKEND.uniform4f(locs[LOC_MAT_BASE + MF_EMISSION], mat.emission.x, mat.emission.y, mat.emission.z, mat.emission.w);
+        if (locs[LOC_MAT_BASE + MF_AMBIENT] != -1)
+            RENDER_BACKEND.uniform4f(locs[LOC_MAT_BASE + MF_AMBIENT], mat.ambient.x, mat.ambient.y, mat.ambient.z, mat.ambient.w);
+        if (locs[LOC_MAT_BASE + MF_DIFFUSE] != -1)
+            RENDER_BACKEND.uniform4f(locs[LOC_MAT_BASE + MF_DIFFUSE], mat.diffuse.x, mat.diffuse.y, mat.diffuse.z, mat.diffuse.w);
+        if (locs[LOC_MAT_BASE + MF_SPECULAR] != -1)
+            RENDER_BACKEND.uniform4f(locs[LOC_MAT_BASE + MF_SPECULAR], mat.specular.x, mat.specular.y, mat.specular.z, mat.specular.w);
+        if (locs[LOC_MAT_BASE + MF_SHININESS] != -1)
+            RENDER_BACKEND.uniform1f(locs[LOC_MAT_BASE + MF_SHININESS], mat.shininess);
+    }
+
+    private static void uploadClipPlanes(int[] locs) {
+        if (locs[LOC_CLIP_PLANES_ENABLED] != -1) {
+            RENDER_BACKEND.uniform1i(locs[LOC_CLIP_PLANES_ENABLED], GLStateManager.anyClipPlaneEnabled() ? 1 : 0);
+        }
+        if (locs[LOC_CLIP_PLANES] != -1) {
+            final ClipPlaneState cps = GLStateManager.getClipPlaneState();
+            clipPlaneBuf.clear();
+            for (int i = 0; i < GLStateManager.MAX_CLIP_PLANES; i++) {
+                cps.putEyePlane(i, clipPlaneBuf);
+            }
+            clipPlaneBuf.flip();
+            RENDER_BACKEND.uniform4(locs[LOC_CLIP_PLANES], clipPlaneBuf);
+        }
+    }
+
+    public static void onDeleteProgram(int program) {
+        programLocations.remove(program);
+    }
+
+    public static boolean hasProgram(int program) {
+        return programLocations.containsKey(program);
+    }
+
+    public static int[] getLocations(int program) {
+        return programLocations.get(program);
+    }
+}

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

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

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

@@ -2,6 +2,7 @@ package com.gtnewhorizons.angelica.glsm;
 
 import com.google.common.collect.ImmutableSet;
 import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
+import com.gtnewhorizons.angelica.glsm.ffp.ShaderManager;
 import com.gtnewhorizons.angelica.glsm.stacks.BooleanStateStack;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
@@ -87,22 +88,20 @@ public class Feature {
               GLStateManager.alphaTest  // GL_ALPHA_TEST enable bit
             , GLStateManager.alphaState // Alpha test function and reference value
             , GLStateManager.blendMode  // GL_BLEND enable bit
-            , GLStateManager.blendState // Blending source and destination functions
-            // Constant blend color
-            // Blending equation
+            , GLStateManager.blendState // Blending source/destination functions, equation, blend color
             , GLStateManager.colorLogicOpState // GL_COLOR_LOGIC_OP enable bit
             , GLStateManager.ditherState // GL_DITHER enable bit
             , GLStateManager.drawBuffer // GL_DRAW_BUFFER setting
             , GLStateManager.indexLogicOpState // GL_INDEX_LOGIC_OP enable bit
-            // Logic op function
+            , GLStateManager.logicOpMode // Logic op function
             , GLStateManager.colorMask   // Color-mode and index-mode writemasks
             , GLStateManager.clearColor  // Color-mode and index-mode clear values
         ));
         attribToFeatures.put(GL11.GL_CURRENT_BIT, ImmutableSet.of(
               GLStateManager.color  // Current RGBA color
+            , ShaderManager.getNormalStack()    // Current normal vector
+            , ShaderManager.getTexCoordStack()  // Current texture coordinates
             // Current color index
-            // Current normal vector
-            // Current texture coordinates
             // Current raster position
             // GL_CURRENT_RASTER_POSITION_VALID flag
             // RGBA color associated with current raster position
@@ -300,6 +299,7 @@ public class Feature {
         ));
         final Set<IStateStack<?>> textureAttribs = new HashSet<>(ImmutableSet.of(
             GLStateManager.activeTextureUnit // Active texture unit
+                // GL_TEXTURE_ENV_MODE + GL_TEXTURE_ENV_COLOR — now per-unit in TexEnvState (added below)
                 // Enable bits for the four texture coordinates
 
                 // Border color for each texture image
@@ -307,17 +307,16 @@ public class Feature {
                 // Magnification function for each texture image
                 // Texture coordinates and wrap mode for each texture image
 
-                // Color and mode for each texture environment
                 // Enable bits GL_TEXTURE_GEN_x, x is S, T, R, and Q
                 // GL_TEXTURE_GEN_MODE setting for S, T, R, and Q
                 // glTexGen plane equations for S, T, R, and Q
                 // Current texture bindings (for example, GL_TEXTURE_BINDING_2D) - Below
         ));
 
-        // Current Texture Bindings - GL_TEXTURE_BINDING_2D
+        // Current Texture Bindings - GL_TEXTURE_BINDING_2D + per-unit TexEnvState
         for(int i = 0 ; i < GLStateManager.MAX_TEXTURE_UNITS; i++) {
             textureAttribs.add(GLStateManager.textures.getTextureUnitBindings(i));
-//            textureAttribs.add(GLStateManager.textures.getInfo(i))
+            textureAttribs.add(GLStateManager.textures.getTexEnvState(i));
         }
 
         // Enable bits GL_TEXTURE_GEN_x where x is S, T, R, or Q

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

@@ -0,0 +1,360 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.recording.ImmediateModeRecorder;
+import com.gtnewhorizons.angelica.glsm.states.VertexAttribState;
+import com.gtnewhorizons.angelica.glsm.states.ViewportState;
+import org.joml.Matrix4f;
+import org.joml.Vector4f;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+import java.nio.ByteOrder;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+import java.nio.ShortBuffer;
+
+/**
+ * Software emulation of GL feedback mode
+ */
+public class FeedbackManager {
+
+    private static final int FB_3D = 0x01;
+    private static final int FB_4D = 0x02;
+    private static final int FB_COLOR = 0x04;
+    private static final int FB_TEXTURE = 0x08;
+
+    private static int renderMode = GL11.GL_RENDER;
+    private static FloatBuffer feedbackBuffer;
+    private static int feedbackBufferSize;
+    private static int feedbackMask;
+    private static int feedbackCount;
+
+    private static final Matrix4f mvpMatrix = new Matrix4f();
+    private static final Vector4f clipVec = new Vector4f();
+
+    private static ByteBuffer readbackBuf = ByteBuffer.allocateDirect(256 * 1024).order(ByteOrder.nativeOrder());
+    private static ByteBuffer indexReadbackBuf = ByteBuffer.allocateDirect(4 * 1024).order(ByteOrder.nativeOrder());
+
+    @FunctionalInterface
+    private interface IndexReader {
+
+        int read(int i);
+    }
+
+    public static boolean isFeedbackMode() {
+        return renderMode == GL11.GL_FEEDBACK;
+    }
+
+    public static void glFeedbackBuffer(int type, FloatBuffer buffer) {
+        if (renderMode == GL11.GL_FEEDBACK) {
+            GLStateManager.LOGGER.error("glFeedbackBuffer called while already in feedback mode");
+            return;
+        }
+        feedbackBuffer = buffer;
+        feedbackBufferSize = buffer.remaining();
+        feedbackMask = computeMask(type);
+        feedbackCount = 0;
+    }
+
+    public static int glRenderMode(int mode) {
+        int result = switch (renderMode) {
+            case GL11.GL_FEEDBACK -> (feedbackCount > feedbackBufferSize) ? -1 : feedbackCount;
+            case GL11.GL_RENDER, GL11.GL_SELECT -> 0;
+            default -> 0;
+        };
+
+        if (mode == GL11.GL_SELECT) {
+            GLStateManager.LOGGER.warn("glRenderMode(GL_SELECT): selection mode not emulated");
+        }
+
+        feedbackCount = 0;
+        renderMode = mode;
+        return result;
+    }
+
+    public static void glPassThrough(float token) {
+        if (renderMode == GL11.GL_FEEDBACK) {
+            feedbackToken(GL11.GL_PASS_THROUGH_TOKEN);
+            feedbackToken(token);
+        }
+    }
+
+    private static void feedbackToken(float token) {
+        if (feedbackCount < feedbackBufferSize) {
+            feedbackBuffer.put(feedbackBuffer.position() + feedbackCount, token);
+        }
+        feedbackCount++;
+    }
+
+    private static void feedbackVertex(float winX, float winY, float winZ, float winW) {
+        feedbackToken(winX);
+        feedbackToken(winY);
+        if ((feedbackMask & FB_3D) != 0) feedbackToken(winZ);
+        if ((feedbackMask & FB_4D) != 0) feedbackToken(winW);
+        if ((feedbackMask & FB_COLOR) != 0) {
+            feedbackToken(1f);
+            feedbackToken(1f);
+            feedbackToken(1f);
+            feedbackToken(1f);
+        }
+        if ((feedbackMask & FB_TEXTURE) != 0) {
+            feedbackToken(0f);
+            feedbackToken(0f);
+            feedbackToken(0f);
+            feedbackToken(1f);
+        }
+    }
+
+    private static void transformAndEmitVertex(float x, float y, float z) {
+        clipVec.set(x, y, z, 1.0f);
+        mvpMatrix.transform(clipVec);
+
+        final float w = clipVec.w;
+        final float ndcX = clipVec.x / w;
+        final float ndcY = clipVec.y / w;
+        final float ndcZ = clipVec.z / w;
+
+        final ViewportState vp = GLStateManager.getViewportState();
+        final float winX = vp.x + vp.width * (ndcX + 1.0f) * 0.5f;
+        final float winY = vp.y + vp.height * (ndcY + 1.0f) * 0.5f;
+        final float winZ = (float) ((vp.depthRangeFar - vp.depthRangeNear) * ndcZ + (vp.depthRangeFar + vp.depthRangeNear)) * 0.5f;
+        final float winW = 1.0f / w;
+
+        feedbackVertex(winX, winY, winZ, winW);
+    }
+
+    private static int positionStride() {
+        final int s = VertexAttribState.get(0).effectiveStride();
+        return (s != 0) ? s : 12;
+    }
+
+    private static long positionOffset() {
+        return VertexAttribState.get(0).offset;
+    }
+
+    public static void processDrawArrays(int mode, int first, int count) {
+        computeMVP();
+        final int stride = positionStride();
+        final long posOffset = positionOffset();
+        final int byteCount = count * stride;
+        ensureReadbackCapacity(byteCount);
+        readbackBuf.clear().limit(byteCount);
+        RENDER_BACKEND.getBufferSubData(GL15.GL_ARRAY_BUFFER, (long) first * stride + posOffset, readbackBuf);
+
+        emitAllPrimitives(mode, count, i -> i, stride);
+    }
+
+    public static void processDrawElements(int mode, int indexCount, int type, long eboOffset) {
+        computeMVP();
+        final int stride = positionStride();
+
+        final int elementSize = VertexAttribState.Attrib.glTypeSizeBytes(type);
+        final int indexByteCount = indexCount * elementSize;
+        ensureIndexReadbackCapacity(indexByteCount);
+        indexReadbackBuf.clear().limit(indexByteCount);
+        RENDER_BACKEND.getBufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, eboOffset, indexReadbackBuf);
+        final ByteBuffer indexBuf = indexReadbackBuf;
+
+        int minIdx = Integer.MAX_VALUE, maxIdx = Integer.MIN_VALUE;
+        for (int i = 0; i < indexCount; i++) {
+            final int idx = ImmediateModeRecorder.readIndex(indexBuf, type, 0, i);
+            if (idx < minIdx) minIdx = idx;
+            if (idx > maxIdx) maxIdx = idx;
+        }
+
+        final long posOffset = positionOffset();
+        final int vertexCount = maxIdx - minIdx + 1;
+        final int byteCount = vertexCount * stride;
+        ensureReadbackCapacity(byteCount);
+        readbackBuf.clear().limit(byteCount);
+        RENDER_BACKEND.getBufferSubData(GL15.GL_ARRAY_BUFFER, (long) minIdx * stride + posOffset, readbackBuf);
+
+        final int base = minIdx;
+        emitAllPrimitives(mode, indexCount, i -> ImmediateModeRecorder.readIndex(indexBuf, type, 0, i) - base, stride);
+    }
+
+    public static void processDrawElements(int mode, ByteBuffer indices) {
+        final int basePos = indices.position();
+        processDrawElementsImpl(mode, indices.remaining(), i -> indices.get(basePos + i) & 0xFF);
+    }
+
+    public static void processDrawElements(int mode, ShortBuffer indices) {
+        final int basePos = indices.position();
+        processDrawElementsImpl(mode, indices.remaining(), i -> indices.get(basePos + i) & 0xFFFF);
+    }
+
+    public static void processDrawElements(int mode, IntBuffer indices) {
+        final int basePos = indices.position();
+        processDrawElementsImpl(mode, indices.remaining(), i -> indices.get(basePos + i));
+    }
+
+    public static void processDrawElements(int mode, int count, int type, ByteBuffer indices) {
+        final int pos = indices.position();
+        final IndexReader reader = switch (type) {
+            case GL11.GL_UNSIGNED_BYTE -> i -> indices.get(pos + i) & 0xFF;
+            case GL11.GL_UNSIGNED_SHORT -> i -> indices.getShort(pos + i * 2) & 0xFFFF;
+            case GL11.GL_UNSIGNED_INT -> i -> indices.getInt(pos + i * 4);
+            default -> i -> 0;
+        };
+        processDrawElementsImpl(mode, count, reader);
+    }
+
+    private static void processDrawElementsImpl(int mode, int count, IndexReader reader) {
+        computeMVP();
+        final int stride = positionStride();
+
+        int minIdx = Integer.MAX_VALUE, maxIdx = Integer.MIN_VALUE;
+        for (int i = 0; i < count; i++) {
+            final int idx = reader.read(i);
+            if (idx < minIdx) minIdx = idx;
+            if (idx > maxIdx) maxIdx = idx;
+        }
+
+        readVerticesFromVBO(minIdx, maxIdx, stride);
+        final int base = minIdx;
+        emitAllPrimitives(mode, count, i -> reader.read(i) - base, stride);
+    }
+
+    private static void computeMVP() {
+        mvpMatrix.set(GLStateManager.getProjectionMatrix()).mul(GLStateManager.getModelViewMatrix());
+    }
+
+    private static int computeMask(int type) {
+        return switch (type) {
+            case GL11.GL_2D -> 0;
+            case GL11.GL_3D -> FB_3D;
+            case GL11.GL_3D_COLOR -> FB_3D | FB_COLOR;
+            case GL11.GL_3D_COLOR_TEXTURE -> FB_3D | FB_COLOR | FB_TEXTURE;
+            case GL11.GL_4D_COLOR_TEXTURE -> FB_3D | FB_4D | FB_COLOR | FB_TEXTURE;
+            default -> 0;
+        };
+    }
+
+    private static void ensureReadbackCapacity(int bytes) {
+        if (readbackBuf.capacity() < bytes) {
+            readbackBuf = ByteBuffer.allocateDirect(bytes).order(ByteOrder.nativeOrder());
+        }
+    }
+
+    private static void ensureIndexReadbackCapacity(int bytes) {
+        if (indexReadbackBuf.capacity() < bytes) {
+            indexReadbackBuf = ByteBuffer.allocateDirect(bytes).order(ByteOrder.nativeOrder());
+        }
+    }
+
+    private static void readVerticesFromVBO(int minIdx, int maxIdx, int stride) {
+        final long posOffset = positionOffset();
+        final int vertexCount = maxIdx - minIdx + 1;
+        final int byteCount = vertexCount * stride;
+        ensureReadbackCapacity(byteCount);
+        readbackBuf.clear().limit(byteCount);
+        RENDER_BACKEND.getBufferSubData(GL15.GL_ARRAY_BUFFER, (long) minIdx * stride + posOffset, readbackBuf);
+    }
+
+    private static void emitVertex(int vertexIndex, int stride) {
+        final float x = readbackBuf.getFloat(vertexIndex * stride);
+        final float y = readbackBuf.getFloat(vertexIndex * stride + 4);
+        final float z = readbackBuf.getFloat(vertexIndex * stride + 8);
+        transformAndEmitVertex(x, y, z);
+    }
+
+    private static void emitAllPrimitives(int mode, int count, IndexReader reader, int stride) {
+        switch (mode) {
+            case GL11.GL_POINTS:
+                for (int i = 0; i < count; i++) {
+                    feedbackToken(GL11.GL_POINT_TOKEN);
+                    emitVertex(reader.read(i), stride);
+                }
+                break;
+
+            case GL11.GL_LINES:
+                for (int i = 0; i + 1 < count; i += 2) {
+                    feedbackToken(i == 0 ? GL11.GL_LINE_RESET_TOKEN : GL11.GL_LINE_TOKEN);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                }
+                break;
+
+            case GL11.GL_LINE_STRIP:
+                for (int i = 0; i + 1 < count; i++) {
+                    feedbackToken(i == 0 ? GL11.GL_LINE_RESET_TOKEN : GL11.GL_LINE_TOKEN);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                }
+                break;
+
+            case GL11.GL_LINE_LOOP:
+                for (int i = 0; i + 1 < count; i++) {
+                    feedbackToken(i == 0 ? GL11.GL_LINE_RESET_TOKEN : GL11.GL_LINE_TOKEN);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                }
+                if (count > 2) {
+                    feedbackToken(GL11.GL_LINE_TOKEN);
+                    emitVertex(reader.read(count - 1), stride);
+                    emitVertex(reader.read(0), stride);
+                }
+                break;
+
+            case GL11.GL_TRIANGLES:
+                for (int i = 0; i + 2 < count; i += 3) {
+                    feedbackToken(GL11.GL_POLYGON_TOKEN);
+                    feedbackToken(3);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                    emitVertex(reader.read(i + 2), stride);
+                }
+                break;
+
+            case GL11.GL_TRIANGLE_STRIP:
+                for (int i = 0; i + 2 < count; i++) {
+                    feedbackToken(GL11.GL_POLYGON_TOKEN);
+                    feedbackToken(3);
+                    if ((i & 1) == 0) {
+                        emitVertex(reader.read(i), stride);
+                        emitVertex(reader.read(i + 1), stride);
+                    } else {
+                        emitVertex(reader.read(i + 1), stride);
+                        emitVertex(reader.read(i), stride);
+                    }
+                    emitVertex(reader.read(i + 2), stride);
+                }
+                break;
+
+            case GL11.GL_TRIANGLE_FAN:
+                for (int i = 1; i + 1 < count; i++) {
+                    feedbackToken(GL11.GL_POLYGON_TOKEN);
+                    feedbackToken(3);
+                    emitVertex(reader.read(0), stride);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                }
+                break;
+
+            case GL11.GL_QUADS:
+                for (int i = 0; i + 3 < count; i += 4) {
+                    feedbackToken(GL11.GL_POLYGON_TOKEN);
+                    feedbackToken(4);
+                    emitVertex(reader.read(i), stride);
+                    emitVertex(reader.read(i + 1), stride);
+                    emitVertex(reader.read(i + 2), stride);
+                    emitVertex(reader.read(i + 3), stride);
+                }
+                break;
+
+            default:
+                throw new UnsupportedOperationException("Feedback mode: unsupported primitive mode 0x" + Integer.toHexString(mode));
+        }
+    }
+
+    static void reset() {
+        renderMode = GL11.GL_RENDER;
+        feedbackBuffer = null;
+        feedbackBufferSize = 0;
+        feedbackMask = 0;
+        feedbackCount = 0;
+    }
+}

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

@@ -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;
@@ -16,179 +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 java.io.PrintStream;
-import java.util.function.Consumer;
-
-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 setupDebugMessageCallback(System.err);
+        return setupDebugMessageCallbackImpl();
     }
 
-    private static void trace(Consumer<String> output) {
-		/*
-		 * We can not just use a fixed stacktrace element offset, because some methods
-		 * are intercepted and some are not. So, check the package name.
-		 */
-		StackTraceElement[] elems = filterStackTrace(new Throwable(), 4).getStackTrace();
-		for (StackTraceElement ste : elems) {
-			output.accept(ste.toString());
-		}
-	}
-
-	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;
-	}
-
-	public static void printTrace(PrintStream stream) {
-		trace(new Consumer<String>() {
-			boolean first = true;
-
-			public void accept(String str) {
-				if (first) {
-					printDetail(stream, "Stacktrace", str);
-					first = false;
-				} else {
-					printDetailLine(stream, "Stacktrace", str);
-				}
-			}
-		});
-	}
-
-    /**
-     * Sets up debug callbacks
-     * @return 0 for failure, 1 for success, 2 for restart required.
-     */
-    public static int setupDebugMessageCallback(PrintStream stream) {
-        if (GLStateManager.capabilities.OpenGL43 || GLStateManager.capabilities.GL_KHR_debug) {
-            LOGGER.info("[GL] Using OpenGL 4.3 for error logging.");
-            KHRDebugCallback proc = new KHRDebugCallback((source, type, id, severity, message) -> {
-                stream.println("[LWJGL] OpenGL debug message");
-                printDetail(stream, "ID", String.format("0x%X", id));
-                printDetail(stream, "Source", getDebugSource(source));
-                printDetail(stream, "Type", getDebugType(type));
-                printDetail(stream, "Severity", getDebugSeverity(severity));
-                printDetail(stream, "Message", message);
-                printTrace(stream);
-            });
-            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.");
-            ARBDebugOutputCallback proc = new ARBDebugOutputCallback((source, type, id, severity, message) -> {
-                stream.println("[LWJGL] ARB_debug_output message");
-                printDetail(stream, "ID", String.format("0x%X", id));
-                printDetail(stream, "Source", getSourceARB(source));
-                printDetail(stream, "Type", getTypeARB(type));
-                printDetail(stream, "Severity", getSeverityARB(severity));
-                printDetail(stream, "Message", message);
-                printTrace(stream);
-            });
-            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.");
-            AMDDebugOutputCallback proc = new AMDDebugOutputCallback((id, category, severity, message) -> {
-                stream.println("[LWJGL] AMD_debug_output message");
-                printDetail(stream, "ID", String.format("0x%X", id));
-                printDetail(stream, "Category", getCategoryAMD(category));
-                printDetail(stream, "Severity", getSeverityAMD(severity));
-                printDetail(stream, "Message", message);
-                printTrace(stream);
-            });
-            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)
+        );
+    }
 
-	private static void printDetail(PrintStream stream, String type, String message) {
-		stream.printf("\t%s: %s\n", type, message);
-	}
+    public static int disableDebugMessages() {
+        return BackendManager.RENDER_BACKEND.disableDebugOutput();
+    }
 
-	private static void printDetailLine(PrintStream stream, String type, String message) {
-		stream.append("    ");
-		for (int i = 0; i < type.length(); i++) {
-			stream.append(" ");
-		}
-		stream.append(message).append("\n");
-	}
-
-	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";
@@ -198,9 +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";
@@ -211,9 +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";
@@ -221,65 +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";
@@ -287,9 +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";
@@ -319,9 +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";
@@ -333,9 +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";
@@ -354,17 +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";
@@ -372,9 +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";
@@ -391,9 +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";
@@ -416,9 +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";
@@ -435,9 +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";
@@ -449,9 +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";
@@ -465,9 +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";
@@ -478,18 +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";
@@ -498,9 +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";
@@ -510,9 +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";
@@ -520,9 +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) {
@@ -544,18 +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";
@@ -575,74 +409,143 @@ public final class GLDebug {
             case GL11.GL_SET -> "SET";
             default -> String.format("0x%X", opcode);
         };
-	}
+    }
 
-	private static DebugState debugState;
+    public static String getFramebufferStatusName(int status) {
+        return switch (status) {
+            case GL30.GL_FRAMEBUFFER_COMPLETE -> "COMPLETE";
+            case GL30.GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT -> "INCOMPLETE_ATTACHMENT";
+            case GL30.GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT -> "INCOMPLETE_MISSING_ATTACHMENT";
+            case GL30.GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER -> "INCOMPLETE_DRAW_BUFFER";
+            case GL30.GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER -> "INCOMPLETE_READ_BUFFER";
+            case GL30.GL_FRAMEBUFFER_UNSUPPORTED -> "UNSUPPORTED";
+            case GL30.GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE -> "INCOMPLETE_MULTISAMPLE";
+            case 0 -> "NO_FRAMEBUFFER_BOUND";
+            default -> String.format("UNKNOWN(0x%X)", status);
+        };
+    }
+
+    public static String getInternalFormatName(int format) {
+        return switch (format) {
+            // Basic
+            case GL11.GL_RGBA -> "RGBA";
+            case GL11.GL_RGB -> "RGB";
+            // 8-bit normalized
+            case GL30.GL_R8 -> "R8";
+            case GL30.GL_RG8 -> "RG8";
+            case GL11.GL_RGB8 -> "RGB8";
+            case GL11.GL_RGBA8 -> "RGBA8";
+            // 8-bit signed normalized
+            case 0x8F94 -> "R8_SNORM";
+            case 0x8F95 -> "RG8_SNORM";
+            case 0x8F96 -> "RGB8_SNORM";
+            case 0x8F97 -> "RGBA8_SNORM";
+            // 16-bit normalized
+            case GL30.GL_R16 -> "R16";
+            case GL30.GL_RG16 -> "RG16";
+            case GL11.GL_RGB16 -> "RGB16";
+            case GL11.GL_RGBA16 -> "RGBA16";
+            // 16-bit float
+            case GL30.GL_R16F -> "R16F";
+            case GL30.GL_RG16F -> "RG16F";
+            case GL30.GL_RGB16F -> "RGB16F";
+            case GL30.GL_RGBA16F -> "RGBA16F";
+            // 32-bit float
+            case GL30.GL_R32F -> "R32F";
+            case GL30.GL_RG32F -> "RG32F";
+            case GL30.GL_RGB32F -> "RGB32F";
+            case GL30.GL_RGBA32F -> "RGBA32F";
+            // Packed
+            case GL30.GL_R11F_G11F_B10F -> "R11F_G11F_B10F";
+            case GL11.GL_RGB10_A2 -> "RGB10_A2";
+            default -> String.format("0x%X", format);
+        };
+    }
+
+    private static DebugState debugState;
 
     private interface DebugState {
-		void nameObject(int id, int object, String name);
-		void pushGroup(String name);
-		void popGroup();
+
+        void 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) {
-            depth++;
-            if (depth > maxDepth) {
-                throw new RuntimeException("Stack overflow");
+        @Override
+        public void pushGroup(String name) {
+            if (depth + 1 > maxDepth) {
+                final StringBuilder sb = new StringBuilder();
+                sb.append("Debug group stack overflow (maxDepth=").append(maxDepth).append("), current stack:\n");
+                for (int i = 0; i < depth; i++) {
+                    sb.append("  [").append(i).append("] ").append(groupStack[i]).append('\n');
+                }
+                sb.append("  -> ").append(name).append(" (rejected)");
+                throw new RuntimeException(sb.toString());
             }
-			KHRDebug.glPushDebugGroup(KHRDebug.GL_DEBUG_SOURCE_APPLICATION, ID, name);
-		}
+            groupStack[depth] = name;
+            BackendManager.RENDER_BACKEND.pushDebugGroup(GL43.GL_DEBUG_SOURCE_APPLICATION, ID, name);
+            depth++;
+        }
 
-		@Override
-		public void popGroup() {
-            depth--;
-            if (depth < 0) {
+        @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) {
@@ -655,40 +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

@@ -0,0 +1,116 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import org.antlr.v4.runtime.tree.ParseTree;
+import org.antlr.v4.runtime.tree.TerminalNode;
+
+import java.util.List;
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Shared GLSL shader transformation utilities.
+ */
+public class GlslTransformUtils {
+
+    private static final String RENAMED_PREFIX = "angelica_renamed_";
+
+    /** Texture function renames */
+    public static final Map<String, String> TEXTURE_RENAMES = Map.ofEntries(
+        Map.entry("texture2D", "texture"),
+        Map.entry("texture3D", "texture"),
+        Map.entry("texture2DLod", "textureLod"),
+        Map.entry("texture3DLod", "textureLod"),
+        Map.entry("texture2DProj", "textureProj"),
+        Map.entry("texture3DProj", "textureProj"),
+        Map.entry("texture2DGrad", "textureGrad"),
+        Map.entry("texture2DGradARB", "textureGrad"),
+        Map.entry("texture3DGrad", "textureGrad"),
+        Map.entry("texelFetch2D", "texelFetch"),
+        Map.entry("texelFetch3D", "texelFetch"),
+        Map.entry("textureSize2D", "textureSize")
+    );
+
+    private static final Pattern TEXTURE_PATTERN = Pattern.compile("\\btexture\\s*\\(|(\\btexture\\b)");
+
+    /** Reserved words added in later GLSL versions that may appear as identifiers in older shaders. */
+    private record ReservedWordRename(Pattern pattern, String replacement) {}
+    private static final Map<Integer, List<ReservedWordRename>> VERSIONED_RESERVED_WORDS = Map.of(
+        400, List.of(
+            new ReservedWordRename(Pattern.compile("\\bsample\\b"), RENAMED_PREFIX + "sample"),
+            new ReservedWordRename(Pattern.compile("\\bsampler\\b(?!\\d)"), RENAMED_PREFIX + "sampler")
+        )
+    );
+
+    public static String replaceTexture(String input) {
+        final Matcher matcher = TEXTURE_PATTERN.matcher(input);
+        final StringBuilder builder = new StringBuilder();
+        while (matcher.find()) {
+            if (matcher.group(1) != null) {
+                matcher.appendReplacement(builder, RENAMED_PREFIX + "texture");
+            } else {
+                matcher.appendReplacement(builder, Matcher.quoteReplacement(matcher.group(0)));
+            }
+        }
+        matcher.appendTail(builder);
+        return builder.toString();
+    }
+
+    public static String renameReservedWords(String source, int targetVersion) {
+        for (var entry : VERSIONED_RESERVED_WORDS.entrySet()) {
+            // Rename identifiers that become reserved words at or above this GLSL version
+            if (targetVersion >= entry.getKey()) {
+                for (var rename : entry.getValue()) {
+                    source = rename.pattern().matcher(source).replaceAll(rename.replacement());
+                }
+            }
+        }
+        return source;
+    }
+
+    public static String restoreReservedWords(String source) {
+        source = source.replace(RENAMED_PREFIX + "texture", "texture");
+        source = source.replace(RENAMED_PREFIX + "sampler", "sampler");
+        source = source.replace(RENAMED_PREFIX + "sample", "sample");
+        return source;
+    }
+
+    public static String getFormattedShader(ParseTree tree, String header) {
+        final StringBuilder sb = new StringBuilder(header + "\n");
+        final String[] tabHolder = {""};
+        getFormattedShader(tree, sb, tabHolder);
+        return sb.toString();
+    }
+
+    private static void getFormattedShader(ParseTree tree, StringBuilder stringBuilder, String[] tabHolder) {
+        if (tree instanceof TerminalNode) {
+            final String text = tree.getText();
+            if (text.equals("<EOF>")) {
+                return;
+            }
+            if (text.equals("#")) {
+                stringBuilder.append("\n#");
+                return;
+            }
+            stringBuilder.append(text);
+            if (text.equals("{")) {
+                stringBuilder.append(" \n\t");
+                tabHolder[0] = "\t";
+            }
+
+            if (text.equals("}")) {
+                if (stringBuilder.length() >= 2) {
+                    stringBuilder.deleteCharAt(stringBuilder.length() - 2);
+                }
+                tabHolder[0] = "";
+                stringBuilder.append(" \n");
+            } else {
+                stringBuilder.append(text.equals(";") ? " \n" + tabHolder[0] : " ");
+            }
+        } else {
+            for (int i = 0; i < tree.getChildCount(); ++i) {
+                getFormattedShader(tree.getChild(i), stringBuilder, tabHolder);
+            }
+        }
+    }
+}

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

@@ -0,0 +1,295 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.states.VertexAttribState;
+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.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+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;
+
+/**
+ * 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) {
+        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;
+        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) {
+        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);
+
+        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) {
+        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 = VertexAttribState.Attrib.glTypeSizeBytes(type);
+
+        // Read source indices from caller's EBO
+        final ByteBuffer src = memAlloc(indexCount * bytesPerIndex);
+        RENDER_BACKEND.getBufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, offset, src);
+        final long srcAddr = memAddress0(src);
+
+        // Allocate output as GL_UNSIGNED_INT
+        final ByteBuffer dst = memAlloc(triIndexCount * 4);
+        final long dstAddr = memAddress0(dst);
+
+        for (int i = 0; i < quadCount; i++) {
+            final int a, b, c, d;
+            switch (type) {
+                case GL11.GL_UNSIGNED_INT -> {
+                    final long p = srcAddr + (long) i * 16;
+                    a = memGetInt(p); b = memGetInt(p + 4); c = memGetInt(p + 8); d = memGetInt(p + 12);
+                }
+                case GL11.GL_UNSIGNED_SHORT -> {
+                    final long p = srcAddr + (long) i * 8;
+                    a = memGetShort(p) & 0xFFFF; b = memGetShort(p + 2) & 0xFFFF;
+                    c = memGetShort(p + 4) & 0xFFFF; d = memGetShort(p + 6) & 0xFFFF;
+                }
+                default /* GL_UNSIGNED_BYTE */ -> {
+                    final long p = srcAddr + (long) i * 4;
+                    a = memGetByte(p) & 0xFF; b = memGetByte(p + 1) & 0xFF;
+                    c = memGetByte(p + 2) & 0xFF; d = memGetByte(p + 3) & 0xFF;
+                }
+            }
+            // GL_LAST_VERTEX_CONVENTION: (a,b,d), (b,c,d)
+            final long o = (long) i * 24;
+            memPutInt(dstAddr + o, a);
+            memPutInt(dstAddr + o + 4, b);
+            memPutInt(dstAddr + o + 8, d);
+            memPutInt(dstAddr + o + 12, b);
+            memPutInt(dstAddr + o + 16, c);
+            memPutInt(dstAddr + o + 20, d);
+        }
+
+        memFree(src);
+        uploadAndDraw(dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4);
+    }
+
+    /**
+     * 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 dstAddr = memAddress0(dst);
+        final int basePos = indices.position();
+
+        for (int i = 0; i < quadCount; i++) {
+            final int base = basePos + i * 4;
+            final int a = indices.get(base), b = indices.get(base + 1), c = indices.get(base + 2), d = indices.get(base + 3);
+            final long o = (long) i * 24;
+            memPutInt(dstAddr + o, a);     memPutInt(dstAddr + o + 4, b);  memPutInt(dstAddr + o + 8, d);
+            memPutInt(dstAddr + o + 12, b); memPutInt(dstAddr + o + 16, c); memPutInt(dstAddr + o + 20, d);
+        }
+
+        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 dstAddr = memAddress0(dst);
+        final int basePos = indices.position();
+
+        for (int i = 0; i < quadCount; i++) {
+            final int base = basePos + i * 4;
+            final short a = indices.get(base), b = indices.get(base + 1), c = indices.get(base + 2), d = indices.get(base + 3);
+            final long o = (long) i * 12;
+            memPutShort(dstAddr + o, a);     memPutShort(dstAddr + o + 2, b);  memPutShort(dstAddr + o + 4, d);
+            memPutShort(dstAddr + o + 6, b); memPutShort(dstAddr + o + 8, c);  memPutShort(dstAddr + o + 10, d);
+        }
+
+        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);
+        final long dstAddr = memAddress0(dst);
+
+        for (int i = 0; i < quadCount; i++) {
+            final int a, b, c, d;
+            switch (type) {
+                case GL11.GL_UNSIGNED_INT -> {
+                    final long p = srcAddr + (long) i * 16;
+                    a = memGetInt(p); b = memGetInt(p + 4); c = memGetInt(p + 8); d = memGetInt(p + 12);
+                }
+                case GL11.GL_UNSIGNED_SHORT -> {
+                    final long p = srcAddr + (long) i * 8;
+                    a = memGetShort(p) & 0xFFFF; b = memGetShort(p + 2) & 0xFFFF;
+                    c = memGetShort(p + 4) & 0xFFFF; d = memGetShort(p + 6) & 0xFFFF;
+                }
+                case GL11.GL_UNSIGNED_BYTE -> {
+                    final long p = srcAddr + (long) i * 4;
+                    a = memGetByte(p) & 0xFF; b = memGetByte(p + 1) & 0xFF;
+                    c = memGetByte(p + 2) & 0xFF; d = memGetByte(p + 3) & 0xFF;
+                }
+                default -> { memFree(dst); return; }
+            }
+            final long o = (long) i * 24;
+            memPutInt(dstAddr + o, a);     memPutInt(dstAddr + o + 4, b);  memPutInt(dstAddr + o + 8, d);
+            memPutInt(dstAddr + o + 12, b); memPutInt(dstAddr + o + 16, c); memPutInt(dstAddr + o + 20, d);
+        }
+
+        uploadAndDraw(dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4);
+    }
+
+    /**
+     * Clean up the shared EBO.
+     */
+    public static void destroy() {
+        if (eboId != 0) {
+            RENDER_BACKEND.deleteBuffers(eboId);
+            eboId = 0;
+            maxQuads = 0;
+        }
+        if (scratchEboId != 0) {
+            RENDER_BACKEND.deleteBuffers(scratchEboId);
+            scratchEboId = 0;
+            scratchEboCapacity = 0;
+        }
+    }
+}

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

@@ -0,0 +1,531 @@
+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 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;
+
+    // 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.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) {
+                GLStateManager.LOGGER.info("GL 3.3 core profile detected, enabling FFP shader emulation.");
+                ShaderManager.getInstance().enable();
+            }
+        }
+    }
+
+    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);
+        RENDER_BACKEND.texImage2D(target, level, internalformat, width, height, border, format, type, pixels);
+        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) {
+        dsaState.textureImage2D(texture, target, level, internalformat, width, height, border, format, type, pixels);
+    }
+
+    public static void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, IntBuffer pixels) {
+        dsaState.textureImage2D(texture, target, level, internalformat, width, height, border, format, type, pixels);
+    }
+
+    public static void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, ByteBuffer pixels) {
+        dsaState.textureSubImage2D(texture, target, level, xoffset, yoffset, width, height, format, type, pixels);
+    }
+
+    public static void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, IntBuffer pixels) {
+        dsaState.textureSubImage2D(texture, target, level, xoffset, yoffset, width, height, format, type, pixels);
+    }
+
+    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);
+        RENDER_BACKEND.texImage1D(target, level, internalformat, width, border, format, type, pixels);
+    }
+
+    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);
+        RENDER_BACKEND.texImage3D(target, level, internalformat, width, height, depth, border, format, type, pixels);
+    }
+
+    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) {
+        RENDER_BACKEND.readPixels(x, y, width, height, format, type, pixels);
+    }
+
+    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) {
+        RENDER_BACKEND.deleteBuffers(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;
+        RENDER_BACKEND.deleteSamplers(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/TransformOptimizer.java

@@ -2,8 +2,6 @@ package com.gtnewhorizons.angelica.glsm;
 
 import com.gtnewhorizons.angelica.glsm.recording.commands.DisplayListCommand;
 import com.gtnewhorizons.angelica.glsm.recording.commands.MultMatrixCmd;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.joml.Matrix4f;
 
 import java.util.ArrayDeque;
@@ -20,8 +18,6 @@ import java.util.List;
  * </ul>
  */
 class TransformOptimizer {
-    private static final Logger LOGGER = LogManager.getLogger("TransformOptimizer");
-
     private final Matrix4f accumulated = new Matrix4f();  // Current accumulated transform
     private final Matrix4f lastEmitted = new Matrix4f();  // Last emitted transform
     private final Deque<Matrix4f> stack = new ArrayDeque<>();  // For Push/Pop
@@ -53,7 +49,7 @@ class TransformOptimizer {
             // After Pop, GL state is restored to the pushed value so lastEmitted should also reflect this
             lastEmitted.set(accumulated);
         } else {
-            LOGGER.warn("[TransformOptimizer] list={} Pop with empty stack - resetting to identity", listId);
+            GLStateManager.LOGGER.warn("[TransformOptimizer] list={} Pop with empty stack - resetting to identity", listId);
             accumulated.identity();
             lastEmitted.identity();
         }

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 +1,322 @@
+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;
+
+/**
+ * Abstract rendering backend.
+ */
+public abstract class RenderBackend {
+
+    public abstract void init();
+    public abstract void shutdown();
+    public abstract boolean isAvailable();
+    public abstract String getName();
+
+    /** Higher priority backends are preferred. */
+    public int getPriority() { return 0; }
+
+    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 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 pixelStoref(int pname, float 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 uniform3(int location, FloatBuffer value);
+    public abstract void uniform4(int location, FloatBuffer 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 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/AngelicaCylinder.java

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

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

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

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

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

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

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

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

@@ -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
@@ -30,56 +30,59 @@ 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
     public void texParameteri(int texture, int target, int pname, int param) {
+        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
     public void texParameterf(int texture, int target, int pname, float param) {
+        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) {
-        ARBDirectStateAccess.glTextureParameter(texture, pname, params);
+        GLStateManager.remapTexClampBuffer(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
@@ -89,7 +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);
         }
     }
@@ -101,44 +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

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

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

@@ -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);
     }
 
@@ -123,10 +121,10 @@ public class DSAUnsupported implements DSAAccess {
 
     @Override
     public int bufferStorage(int target, FloatBuffer data, int usage) {
-        final int buffer = GL15.glGenBuffers();
-        GL15.glBindBuffer(target, buffer);
-        RenderSystem.bufferData(target, data, usage);
-        GL15.glBindBuffer(target, 0);
+        final int buffer = RENDER_BACKEND.genBuffers();
+        GLStateManager.glBindBuffer(target, buffer);
+        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

@@ -0,0 +1,364 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import java.util.Arrays;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.states.TexEnvState;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL12;
+import org.lwjgl.opengl.GL13;
+
+/**
+ * Packed-long fragment shader permutation key for FFP emulation.
+ *
+ * Layout:
+ *   long[0]: global bits (10) + unit 0 (47 bits at offset 10)
+ *   long[1..3]: unit 1..3 (47 bits each, low-aligned)
+ * Only max(1, nrEnabledUnits) longs are significant.
+ *
+ * Per-unit packing (47 bits):
+ *   0:     enabled
+ *   1-3:   mode (MODULATE=0..COMBINE=5)
+ *   4:     needsEnvColor
+ *   5-8:   combineRgb (encoded 0-7)
+ *   9-12:  combineAlpha (encoded 0-7)
+ *   13-14: scaleShiftRgb
+ *   15-16: scaleShiftAlpha
+ *   17-21: arg0 RGB (source:3 + operand:2)
+ *   22-26: arg1 RGB
+ *   27-31: arg2 RGB
+ *   32-36: arg0 Alpha
+ *   37-41: arg1 Alpha
+ *   42-46: arg2 Alpha
+ */
+public final class FragmentKey {
+    public static final int TEX_ENV_MODULATE = 0;
+    public static final int TEX_ENV_REPLACE  = 1;
+    public static final int TEX_ENV_ADD      = 2;
+    public static final int TEX_ENV_DECAL    = 3;
+    public static final int TEX_ENV_BLEND    = 4;
+    public static final int TEX_ENV_COMBINE  = 5;
+
+    public static final int COMBINE_REPLACE      = 0;
+    public static final int COMBINE_MODULATE     = 1;
+    public static final int COMBINE_ADD          = 2;
+    public static final int COMBINE_ADD_SIGNED   = 3;
+    public static final int COMBINE_INTERPOLATE  = 4;
+    public static final int COMBINE_SUBTRACT     = 5;
+    public static final int COMBINE_DOT3_RGB     = 6;
+    public static final int COMBINE_DOT3_RGBA    = 7;
+
+    public static final int SRC_TEXTURE       = 0;
+    public static final int SRC_CONSTANT      = 1;
+    public static final int SRC_PRIMARY_COLOR = 2;
+    public static final int SRC_PREVIOUS      = 3;
+
+    public static final int OP_SRC_COLOR           = 0;
+    public static final int OP_ONE_MINUS_SRC_COLOR = 1;
+    public static final int OP_SRC_ALPHA           = 2;
+    public static final int OP_ONE_MINUS_SRC_ALPHA = 3;
+
+    public static final int FOG_NONE   = 0;
+    public static final int FOG_LINEAR = 1;
+    public static final int FOG_EXP    = 2;
+    public static final int FOG_EXP2   = 3;
+
+    private static final int GLOBAL_BITS = 10;
+    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 U_ENABLED         = 0;
+    private static final int U_MODE            = 1;   // 3 bits
+    private static final int U_NEEDS_ENV_COLOR = 4;   // 1 bit
+    private static final int U_COMBINE_RGB     = 5;   // 4 bits
+    private static final int U_COMBINE_ALPHA   = 9;   // 4 bits
+    private static final int U_SCALE_RGB       = 13;  // 2 bits
+    private static final int U_SCALE_ALPHA     = 15;  // 2 bits
+    private static final int U_ARG0_RGB        = 17;  // 5 bits (source:3 + operand:2)
+    private static final int U_ARG1_RGB        = 22;  // 5 bits
+    private static final int U_ARG2_RGB        = 27;  // 5 bits
+    private static final int U_ARG0_ALPHA      = 32;  // 5 bits
+    private static final int U_ARG1_ALPHA      = 37;  // 5 bits
+    private static final int U_ARG2_ALPHA      = 42;  // 5 bits
+
+    static final int MAX_UNITS = 4;
+
+    private final long[] packed;
+    private final int hash;
+
+    private FragmentKey(long[] packed, int hash) {
+        this.packed = packed;
+        this.hash = hash;
+    }
+
+    /**
+     * Pack current GLSM fragment state into pre-allocated output array.
+     * @param out must be at least MAX_UNITS (4) longs
+     * @return number of significant longs (1..4)
+     */
+    public static int packFromState(long[] out) {
+        long global = 0;
+
+        // Fog
+        if (GLStateManager.getFogMode().isEnabled()) {
+            final int fogMode = switch (GLStateManager.getFogState().getFogMode()) {
+                case GL11.GL_LINEAR -> FOG_LINEAR;
+                case GL11.GL_EXP    -> FOG_EXP;
+                case GL11.GL_EXP2   -> FOG_EXP2;
+                default -> FOG_NONE;
+            };
+            global |= (long) fogMode;
+        }
+
+        // Alpha test
+        if (GLStateManager.getAlphaTest().isEnabled()) {
+            global |= (1L << BIT_ALPHA_TEST);
+            global |= ((long) (encodeAlphaFunc(GLStateManager.getAlphaState().getFunction()) & 0x7)) << BIT_ALPHA_FUNC;
+        }
+
+        // Separate specular
+        if (GLStateManager.getLightingState().isEnabled()
+            && GLStateManager.getLightModel().colorControl == GL12.GL_SEPARATE_SPECULAR_COLOR) {
+            global |= (1L << BIT_SEPARATE_SPECULAR);
+        }
+
+        // Per-unit state
+        int highestEnabled = -1;
+        long unit0Bits = 0;
+        for (int i = 0; i < MAX_UNITS; i++) {
+            final boolean texEnabled = GLStateManager.getTextures().getTextureUnitStates(i).isEnabled();
+            if (texEnabled) highestEnabled = i;
+
+            final long unitBits = packUnit(i, texEnabled);
+            if (i == 0) {
+                unit0Bits = unitBits;
+            } else {
+                out[i] = unitBits;
+            }
+        }
+
+        final int nrEnabled = highestEnabled + 1;
+        global |= ((long) (nrEnabled & 0x7)) << BIT_NR_ENABLED_UNITS;
+        global |= (unit0Bits << GLOBAL_BITS);
+        out[0] = global;
+
+        return Math.max(1, nrEnabled);
+    }
+
+    private static long packUnit(int unitIndex, boolean texEnabled) {
+        if (!texEnabled) return 0;
+
+        final TexEnvState envState = GLStateManager.getTextures().getTexEnvState(unitIndex);
+        final int mode = encodeTexEnvMode(envState.mode);
+
+        long bits = 1L; // enabled
+        bits |= ((long) (mode & 0x7)) << U_MODE;
+
+        boolean needsEnvColor = (mode == TEX_ENV_BLEND);
+
+        if (mode == TEX_ENV_COMBINE) {
+            final int combRgb = encodeCombineFunc(envState.combineRgb);
+            final int combAlpha = encodeCombineFunc(envState.combineAlpha);
+            bits |= ((long) (combRgb & 0xF)) << U_COMBINE_RGB;
+            bits |= ((long) (combAlpha & 0xF)) << U_COMBINE_ALPHA;
+            bits |= ((long) (encodeScale(envState.scaleRgb) & 0x3)) << U_SCALE_RGB;
+            bits |= ((long) (encodeScale(envState.scaleAlpha) & 0x3)) << U_SCALE_ALPHA;
+
+            // Only pack args actually used by each channel's combine function.
+            // Unused arg slots stay 0, preventing TexEnvState defaults from inflating the cache.
+            final int numArgsRgb = combineNumArgs(combRgb);
+            final int numArgsAlpha = combineNumArgs(combAlpha);
+            final int maxArgs = Math.max(numArgsRgb, numArgsAlpha);
+
+            for (int a = 0; a < maxArgs; a++) {
+                if (a < numArgsRgb) {
+                    final int srcR = encodeSource(envState.sourceRgb[a]);
+                    final int opR = encodeOperand(envState.operandRgb[a]);
+                    bits |= ((long) ((srcR & 0x7) | ((opR & 0x3) << 3))) << (U_ARG0_RGB + a * 5);
+                    if (srcR == SRC_CONSTANT) needsEnvColor = true;
+                }
+                if (a < numArgsAlpha) {
+                    final int srcA = encodeSource(envState.sourceAlpha[a]);
+                    final int opA = encodeOperand(envState.operandAlpha[a]);
+                    bits |= ((long) ((srcA & 0x7) | ((opA & 0x3) << 3))) << (U_ARG0_ALPHA + a * 5);
+                    if (srcA == SRC_CONSTANT) needsEnvColor = true;
+                }
+            }
+        }
+
+        if (needsEnvColor) {
+            bits |= (1L << U_NEEDS_ENV_COLOR);
+        }
+
+        return bits;
+    }
+
+    /** Create FragmentKey from packed scratch data. Only called on cache miss. */
+    public static FragmentKey fromPacked(long[] scratch, int len) {
+        final long[] copy = Arrays.copyOf(scratch, len);
+        return new FragmentKey(copy, Arrays.hashCode(copy));
+    }
+
+    /** Convenience: pack + create. Allocates. For infrequent paths. */
+    public static FragmentKey fromState() {
+        final long[] scratch = new long[MAX_UNITS];
+        final int len = packFromState(scratch);
+        return fromPacked(scratch, len);
+    }
+
+    @Override
+    public int hashCode() {
+        return hash;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (!(obj instanceof FragmentKey other)) return false;
+        if (hash != other.hash) return false;
+        return Arrays.equals(packed, other.packed);
+    }
+
+    public int fogMode()              { return (int) (packed[0] & 0x3); }
+    public boolean alphaTestEnabled() { return ((packed[0] >> BIT_ALPHA_TEST) & 1) != 0; }
+    public int alphaTestFunc()        { return (int) ((packed[0] >> BIT_ALPHA_FUNC) & 0x7); }
+    public boolean separateSpecular() { return ((packed[0] >> BIT_SEPARATE_SPECULAR) & 1) != 0; }
+    public int nrEnabledUnits()       { return (int) ((packed[0] >> BIT_NR_ENABLED_UNITS) & 0x7); }
+
+    private long unitBits(int i) {
+        return (i == 0) ? (packed[0] >>> GLOBAL_BITS) : packed[i];
+    }
+
+    public boolean unitEnabled(int i)       { return (unitBits(i) & 1) != 0; }
+    public int unitMode(int i)              { return (int) ((unitBits(i) >> U_MODE) & 0x7); }
+    public boolean unitNeedsEnvColor(int i) { return ((unitBits(i) >> U_NEEDS_ENV_COLOR) & 1) != 0; }
+    public int unitCombineRgb(int i)        { return (int) ((unitBits(i) >> U_COMBINE_RGB) & 0xF); }
+    public int unitCombineAlpha(int i)      { return (int) ((unitBits(i) >> U_COMBINE_ALPHA) & 0xF); }
+    public int unitScaleShiftRgb(int i)     { return (int) ((unitBits(i) >> U_SCALE_RGB) & 0x3); }
+    public int unitScaleShiftAlpha(int i)   { return (int) ((unitBits(i) >> U_SCALE_ALPHA) & 0x3); }
+
+    public int unitSourceRgb(int i, int arg)    { return (int) ((unitBits(i) >> (U_ARG0_RGB + arg * 5)) & 0x7); }
+    public int unitOperandRgb(int i, int arg)   { return (int) ((unitBits(i) >> (U_ARG0_RGB + arg * 5 + 3)) & 0x3); }
+    public int unitSourceAlpha(int i, int arg)  { return (int) ((unitBits(i) >> (U_ARG0_ALPHA + arg * 5)) & 0x7); }
+    public int unitOperandAlpha(int i, int arg) { return (int) ((unitBits(i) >> (U_ARG0_ALPHA + arg * 5 + 3)) & 0x3); }
+
+    public boolean textureEnabled() {
+        for (int i = 0; i < nrEnabledUnits(); i++) {
+            if (unitEnabled(i)) return true;
+        }
+        return false;
+    }
+
+    public boolean lightmapEnabled() {
+        return nrEnabledUnits() > 1 && unitEnabled(1);
+    }
+
+    private static int encodeAlphaFunc(int glFunc) {
+        return glFunc & 0x7;
+    }
+
+    static int encodeTexEnvMode(int glMode) {
+        return switch (glMode) {
+            case GL11.GL_MODULATE -> TEX_ENV_MODULATE;
+            case GL11.GL_REPLACE  -> TEX_ENV_REPLACE;
+            case GL11.GL_ADD      -> TEX_ENV_ADD;
+            case GL11.GL_DECAL    -> TEX_ENV_DECAL;
+            case GL11.GL_BLEND    -> TEX_ENV_BLEND;
+            case GL13.GL_COMBINE -> TEX_ENV_COMBINE;
+            default -> TEX_ENV_MODULATE;
+        };
+    }
+
+    static int encodeCombineFunc(int glFunc) {
+        return switch (glFunc) {
+            case GL11.GL_REPLACE     -> COMBINE_REPLACE;
+            case GL11.GL_MODULATE    -> COMBINE_MODULATE;
+            case GL11.GL_ADD         -> COMBINE_ADD;
+            case GL13.GL_ADD_SIGNED  -> COMBINE_ADD_SIGNED;
+            case GL13.GL_INTERPOLATE -> COMBINE_INTERPOLATE;
+            case GL13.GL_SUBTRACT    -> COMBINE_SUBTRACT;
+            case GL13.GL_DOT3_RGB    -> COMBINE_DOT3_RGB;
+            case GL13.GL_DOT3_RGBA   -> COMBINE_DOT3_RGBA;
+            default -> COMBINE_REPLACE;
+        };
+    }
+
+    static int encodeSource(int glSource) {
+        return switch (glSource) {
+            case GL11.GL_TEXTURE       -> SRC_TEXTURE;
+            case GL13.GL_CONSTANT      -> SRC_CONSTANT;
+            case GL13.GL_PRIMARY_COLOR -> SRC_PRIMARY_COLOR;
+            case GL13.GL_PREVIOUS      -> SRC_PREVIOUS;
+            default -> {
+                GLStateManager.LOGGER.debug("Unknown TexEnv source 0x{}, falling back to SRC_PREVIOUS", Integer.toHexString(glSource));
+                yield SRC_PREVIOUS;
+            }
+        };
+    }
+
+    static int encodeOperand(int glOperand) {
+        return switch (glOperand) {
+            case GL11.GL_SRC_COLOR           -> OP_SRC_COLOR;
+            case GL11.GL_ONE_MINUS_SRC_COLOR -> OP_ONE_MINUS_SRC_COLOR;
+            case GL11.GL_SRC_ALPHA           -> OP_SRC_ALPHA;
+            case GL11.GL_ONE_MINUS_SRC_ALPHA -> OP_ONE_MINUS_SRC_ALPHA;
+            default -> OP_SRC_COLOR;
+        };
+    }
+
+    /** Number of source/operand args used by the given (encoded) combine function. */
+    public static int combineNumArgs(int func) {
+        return switch (func) {
+            case COMBINE_REPLACE -> 1;
+            case COMBINE_INTERPOLATE -> 3;
+            default -> 2; // MODULATE, ADD, ADD_SIGNED, SUBTRACT, DOT3_*
+        };
+    }
+
+    private static int encodeScale(float scale) {
+        if (scale >= 4.0f) return 2;
+        if (scale >= 2.0f) return 1;
+        return 0;
+    }
+
+    public static int decodeAlphaFunc(int encoded) {
+        return 0x0200 | encoded;
+    }
+
+    @Override
+    public String toString() {
+        final String fogName = switch (fogMode()) {
+            case FOG_NONE   -> "NONE";
+            case FOG_LINEAR -> "LINEAR";
+            case FOG_EXP    -> "EXP";
+            case FOG_EXP2   -> "EXP2";
+            default -> "?";
+        };
+        final StringBuilder sb = new StringBuilder();
+        sb.append(String.format("FFPFragmentKey[fog=%s alpha=%b(%s) specSep=%b units=%d",
+            fogName, alphaTestEnabled(),
+            alphaTestEnabled() ? String.format("0x%04X", decodeAlphaFunc(alphaTestFunc())) : "-",
+            separateSpecular(), nrEnabledUnits()));
+        for (int i = 0; i < nrEnabledUnits(); i++) {
+            if (!unitEnabled(i)) {
+                sb.append(String.format(" u%d=OFF", i));
+            } else {
+                final String modeName = switch (unitMode(i)) {
+                    case TEX_ENV_MODULATE -> "MOD";
+                    case TEX_ENV_REPLACE  -> "REPL";
+                    case TEX_ENV_ADD      -> "ADD";
+                    case TEX_ENV_DECAL    -> "DEC";
+                    case TEX_ENV_BLEND    -> "BL";
+                    case TEX_ENV_COMBINE  -> "COMB";
+                    default -> "?";
+                };
+                sb.append(String.format(" u%d=%s", i, modeName));
+            }
+        }
+        sb.append(']');
+        return sb.toString();
+    }
+}

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

@@ -0,0 +1,316 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import org.lwjgl.opengl.GL11;
+
+/**
+ * Generates GLSL 330 core fragment shaders for FFP emulation.
+ * Supports per-unit texenv chain including GL_COMBINE mode.
+ * Follows Mesa's ff_fragment_shader.c and st_nir_lower_fog.c.
+ */
+public final class FragmentShaderGenerator {
+
+    private FragmentShaderGenerator() {}
+
+    public static String generate(FragmentKey key) {
+        final StringBuilder sb = new StringBuilder(2048);
+        sb.append("#version 330 core\n\n");
+
+        emitInputs(sb, key);
+        emitUniforms(sb, key);
+        sb.append("out vec4 fragColor;\n\n");
+
+        sb.append("void main() {\n");
+        emitTextureSampling(sb, key);
+        emitTexEnvChain(sb, key);
+        emitSpecularAdd(sb, key);
+        emitAlphaTest(sb, key);
+        emitFog(sb, key);
+        sb.append("  fragColor = color;\n");
+        sb.append("}\n");
+
+        return sb.toString();
+    }
+
+    private static void emitInputs(StringBuilder sb, FragmentKey key) {
+        sb.append("// Inputs from vertex shader\n");
+        sb.append("in vec4 v_Color;\n");
+        if (key.separateSpecular()) {
+            sb.append("in vec3 v_SpecularColor;\n");
+        }
+        if (key.textureEnabled()) {
+            sb.append("in vec4 v_TexCoord0;\n");
+        }
+        if (key.lightmapEnabled()) {
+            sb.append("in vec4 v_TexCoord1;\n");
+        }
+        if (key.fogMode() != FragmentKey.FOG_NONE) {
+            sb.append("in float v_FogCoord;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitUniforms(StringBuilder sb, FragmentKey key) {
+        // Samplers for each enabled unit
+        for (int i = 0; i < key.nrEnabledUnits(); i++) {
+            if (key.unitEnabled(i)) {
+                sb.append("uniform sampler2D u_Sampler").append(i).append(";\n");
+            }
+        }
+        if (key.alphaTestEnabled()) {
+            sb.append("uniform float u_AlphaRef;\n");
+        }
+        // Per-unit texEnvColor uniforms
+        for (int i = 0; i < key.nrEnabledUnits(); i++) {
+            if (key.unitEnabled(i) && key.unitNeedsEnvColor(i)) {
+                sb.append("uniform vec4 u_TexEnvColor").append(i).append(";\n");
+            }
+        }
+        if (key.fogMode() != FragmentKey.FOG_NONE) {
+            sb.append("uniform vec4 u_FogParams;\n");
+            sb.append("uniform vec4 u_FogColor;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitTextureSampling(StringBuilder sb, FragmentKey key) {
+        for (int i = 0; i < key.nrEnabledUnits(); i++) {
+            if (!key.unitEnabled(i)) continue;
+            // 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");
+        }
+    }
+
+    private static void emitTexEnvChain(StringBuilder sb, FragmentKey key) {
+        if (!key.textureEnabled()) {
+            sb.append("  // No texture -- vertex color only\n");
+            sb.append("  vec4 color = v_Color;\n");
+            return;
+        }
+
+        // Process units in order; "previous" starts as vertex color
+        boolean firstUnit = true;
+        for (int i = 0; i < key.nrEnabledUnits(); i++) {
+            if (!key.unitEnabled(i)) continue;
+
+            final String texVar = "tex" + i + "Color";
+            final String envColorVar = "u_TexEnvColor" + i;
+            final String prevVar = firstUnit ? "v_Color" : "color";
+            final String assign = firstUnit ? "  vec4 color = " : "  color = ";
+
+            if (key.unitMode(i) == FragmentKey.TEX_ENV_COMBINE) {
+                emitCombineUnit(sb, key, i, texVar, envColorVar, prevVar, assign);
+            } else {
+                emitSimpleUnit(sb, key, i, texVar, envColorVar, prevVar, assign);
+            }
+            firstUnit = false;
+        }
+    }
+
+    private static void emitSimpleUnit(StringBuilder sb, FragmentKey key, int unit, String texVar, String envColorVar, String prevVar, String assign) {
+        switch (key.unitMode(unit)) {
+            case FragmentKey.TEX_ENV_REPLACE -> {
+                sb.append("  // Unit ").append(unit).append(" (REPLACE)\n");
+                sb.append(assign).append(texVar).append(";\n");
+            }
+            case FragmentKey.TEX_ENV_ADD -> {
+                sb.append("  // Unit ").append(unit).append(" (ADD)\n");
+                sb.append(assign).append("vec4(clamp(").append(prevVar).append(".rgb + ").append(texVar).append(".rgb, 0.0, 1.0), ")
+                    .append(prevVar).append(".a * ").append(texVar).append(".a);\n");
+            }
+            case FragmentKey.TEX_ENV_DECAL -> {
+                sb.append("  // Unit ").append(unit).append(" (DECAL)\n");
+                sb.append(assign).append("vec4(mix(").append(prevVar).append(".rgb, ").append(texVar).append(".rgb, ").append(texVar).append(".a), ")
+                    .append(prevVar).append(".a);\n");
+            }
+            case FragmentKey.TEX_ENV_BLEND -> {
+                sb.append("  // Unit ").append(unit).append(" (BLEND)\n");
+                sb.append(assign).append("vec4(").append(prevVar).append(".rgb * (vec3(1.0) - ").append(texVar).append(".rgb) + ")
+                    .append(envColorVar).append(".rgb * ").append(texVar).append(".rgb, ")
+                    .append(prevVar).append(".a * ").append(texVar).append(".a);\n");
+            }
+            default -> { // MODULATE
+                sb.append("  // Unit ").append(unit).append(" (MODULATE)\n");
+                sb.append(assign).append(prevVar).append(" * ").append(texVar).append(";\n");
+            }
+        }
+    }
+
+    /** Emit a GL_COMBINE texenv unit */
+    private static void emitCombineUnit(StringBuilder sb, FragmentKey key, int unit, String texVar, String envColorVar, String prevVar, String assign) {
+        sb.append("  // Unit ").append(unit).append(" (COMBINE)\n");
+
+        final String rgbResult = "combRgb" + unit;
+        final String alphaResult = "combAlpha" + unit;
+
+        if (key.unitCombineRgb(unit) == FragmentKey.COMBINE_DOT3_RGBA) {
+            sb.append("  vec3 ").append(rgbResult).append(";\n");
+            sb.append("  {\n");
+            emitCombineChannel(sb, key, unit, texVar, envColorVar, prevVar, true);
+            sb.append("  }\n");
+            sb.append(assign).append("vec4(").append(rgbResult).append(", ").append(rgbResult).append(".x);\n");
+        } else {
+            sb.append("  vec3 ").append(rgbResult).append(";\n");
+            sb.append("  float ").append(alphaResult).append(";\n");
+            sb.append("  {\n");
+            emitCombineChannel(sb, key, unit, texVar, envColorVar, prevVar, true);
+            emitCombineChannel(sb, key, unit, texVar, envColorVar, prevVar, false);
+            sb.append("  }\n");
+            sb.append(assign).append("vec4(").append(rgbResult).append(", ").append(alphaResult).append(");\n");
+        }
+    }
+
+    /**
+     * Emit one channel (RGB or Alpha) of a GL_COMBINE unit.
+     */
+    private static void emitCombineChannel(StringBuilder sb, FragmentKey key, int unit, String texVar, String envColorVar, String prevVar, boolean isRgb) {
+        final String suffix = isRgb ? "Rgb" : "Alpha";
+        final String type = isRgb ? "vec3" : "float";
+        final int combineFunc = isRgb ? key.unitCombineRgb(unit) : key.unitCombineAlpha(unit);
+        final int scaleShift = isRgb ? key.unitScaleShiftRgb(unit) : key.unitScaleShiftAlpha(unit);
+
+        // Guard: DOT3 is invalid for alpha channel — fallback to REPLACE
+        final int effectiveFunc;
+        if (!isRgb && (combineFunc == FragmentKey.COMBINE_DOT3_RGB || combineFunc == FragmentKey.COMBINE_DOT3_RGBA)) {
+            effectiveFunc = FragmentKey.COMBINE_REPLACE;
+        } else {
+            effectiveFunc = combineFunc;
+        }
+
+        // Determine how many args we need
+        final int numArgs = combineNumArgs(effectiveFunc);
+
+        // Emit argument resolution
+        for (int a = 0; a < numArgs; a++) {
+            final int source = isRgb ? key.unitSourceRgb(unit, a) : key.unitSourceAlpha(unit, a);
+            final int operand = isRgb ? key.unitOperandRgb(unit, a) : key.unitOperandAlpha(unit, a);
+            final String argName = "arg" + suffix + a + "_" + unit;
+            final String sourceExpr = resolveSource(source, texVar, envColorVar, prevVar);
+            final String operandExpr = applyOperand(sourceExpr, operand, isRgb);
+            sb.append("    ").append(type).append(" ").append(argName).append(" = ").append(operandExpr).append(";\n");
+        }
+
+        // Emit combine operation
+        final String resultName = "comb" + suffix + unit;
+        final String a0 = "arg" + suffix + "0_" + unit;
+        final String a1 = "arg" + suffix + "1_" + unit;
+        final String a2 = "arg" + suffix + "2_" + unit;
+
+        sb.append("    ").append(resultName).append(" = ");
+        switch (effectiveFunc) {
+            case FragmentKey.COMBINE_REPLACE -> sb.append(a0);
+            case FragmentKey.COMBINE_MODULATE -> sb.append(a0).append(" * ").append(a1);
+            case FragmentKey.COMBINE_ADD -> sb.append(a0).append(" + ").append(a1);
+            case FragmentKey.COMBINE_ADD_SIGNED ->
+                sb.append(a0).append(" + ").append(a1).append(" - ").append(isRgb ? "vec3(0.5)" : "0.5");
+            case FragmentKey.COMBINE_SUBTRACT -> sb.append(a0).append(" - ").append(a1);
+            case FragmentKey.COMBINE_INTERPOLATE ->
+                sb.append("mix(").append(a1).append(", ").append(a0).append(", ").append(a2).append(")");
+            case FragmentKey.COMBINE_DOT3_RGB, FragmentKey.COMBINE_DOT3_RGBA ->
+                sb.append("vec3(4.0 * dot(").append(a0).append(" - vec3(0.5), ").append(a1).append(" - vec3(0.5)))");
+            default -> sb.append(a0); // fallback to REPLACE
+        }
+        sb.append(";\n");
+
+        // Apply scale
+        if (scaleShift > 0) {
+            final String scaleFactor = scaleShift == 1 ? "2.0" : "4.0";
+            sb.append("    ").append(resultName).append(" *= ").append(scaleFactor).append(";\n");
+        }
+
+        // Clamp
+        sb.append("    ").append(resultName).append(" = clamp(").append(resultName).append(", ")
+            .append(isRgb ? "vec3(0.0), vec3(1.0)" : "0.0, 1.0").append(");\n");
+    }
+
+    private static String resolveSource(int source, String texVar, String envColorVar, String prevVar) {
+        return switch (source) {
+            case FragmentKey.SRC_TEXTURE -> texVar;
+            case FragmentKey.SRC_CONSTANT -> envColorVar;
+            case FragmentKey.SRC_PRIMARY_COLOR -> "v_Color";
+            case FragmentKey.SRC_PREVIOUS -> prevVar;
+            default -> prevVar;
+        };
+    }
+
+    private static String applyOperand(String sourceExpr, int operand, boolean isRgb) {
+        if (isRgb) {
+            return switch (operand) {
+                case FragmentKey.OP_SRC_COLOR -> sourceExpr + ".rgb";
+                case FragmentKey.OP_ONE_MINUS_SRC_COLOR -> "(vec3(1.0) - " + sourceExpr + ".rgb)";
+                case FragmentKey.OP_SRC_ALPHA -> "vec3(" + sourceExpr + ".a)";
+                case FragmentKey.OP_ONE_MINUS_SRC_ALPHA -> "vec3(1.0 - " + sourceExpr + ".a)";
+                default -> sourceExpr + ".rgb";
+            };
+        } else {
+            return switch (operand) {
+                case FragmentKey.OP_SRC_ALPHA -> sourceExpr + ".a";
+                case FragmentKey.OP_ONE_MINUS_SRC_ALPHA -> "(1.0 - " + sourceExpr + ".a)";
+                // Per GL spec, alpha channel operands are SRC_ALPHA or ONE_MINUS_SRC_ALPHA only, but handle color operands gracefully
+                case FragmentKey.OP_SRC_COLOR -> sourceExpr + ".a";
+                case FragmentKey.OP_ONE_MINUS_SRC_COLOR -> "(1.0 - " + sourceExpr + ".a)";
+                default -> sourceExpr + ".a";
+            };
+        }
+    }
+
+    private static int combineNumArgs(int func) {
+        return FragmentKey.combineNumArgs(func);
+    }
+
+    private static void emitSpecularAdd(StringBuilder sb, FragmentKey key) {
+        if (key.separateSpecular()) {
+            sb.append("  // Add separate specular\n");
+            sb.append("  color.rgb += v_SpecularColor;\n");
+        }
+    }
+
+    private static void emitAlphaTest(StringBuilder sb, FragmentKey key) {
+        if (!key.alphaTestEnabled()) return;
+
+        sb.append("  // Alpha test\n");
+        final int func = FragmentKey.decodeAlphaFunc(key.alphaTestFunc());
+
+        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");
+            case GL11.GL_LEQUAL ->
+                sb.append("  if (color.a > u_AlphaRef) 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");
+            case GL11.GL_GEQUAL ->
+                sb.append("  if (color.a < u_AlphaRef) discard;\n");
+            case GL11.GL_ALWAYS -> {}
+        }
+    }
+
+    private static void emitFog(StringBuilder sb, FragmentKey key) {
+        final int fogMode = key.fogMode();
+        if (fogMode == FragmentKey.FOG_NONE) return;
+
+        sb.append("  // Fog\n");
+        sb.append("  float f;\n");
+
+        switch (fogMode) {
+            case FragmentKey.FOG_LINEAR ->
+                sb.append("  f = v_FogCoord * u_FogParams.x + u_FogParams.y;\n");
+            case FragmentKey.FOG_EXP ->
+                sb.append("  f = exp2(-(v_FogCoord * u_FogParams.z));\n");
+            case FragmentKey.FOG_EXP2 -> {
+                sb.append("  float fogTmp = v_FogCoord * u_FogParams.w;\n");
+                sb.append("  f = exp2(-(fogTmp * fogTmp));\n");
+            }
+        }
+
+        sb.append("  f = clamp(f, 0.0, 1.0);\n");
+        sb.append("  color.rgb = mix(u_FogColor.rgb, color.rgb, f);\n");
+    }
+}

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

@@ -0,0 +1,104 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+/**
+ * Generates GLSL 330 core geometry shaders for wide line emulation.
+ */
+public final class GeometryShaderGenerator {
+
+    private GeometryShaderGenerator() {}
+
+    public static String generate(VertexKey key) {
+        final StringBuilder sb = new StringBuilder(1024);
+        sb.append("#version 330 core\n\n");
+
+        sb.append("layout(lines) in;\n");
+        sb.append("layout(triangle_strip, max_vertices = 4) out;\n\n");
+
+        sb.append("uniform vec2 u_ViewportSize;\n");
+        sb.append("uniform float u_LineWidth;\n\n");
+
+        sb.append("// Pass-through varyings\n");
+        sb.append("in vec4 v_Color_gs[];\n");
+        if (key.separateSpecular()) {
+            sb.append("in vec3 v_SpecularColor_gs[];\n");
+        }
+        if (key.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.fogEnabled()) {
+            sb.append("in float v_FogCoord_gs[];\n");
+        }
+        sb.append('\n');
+
+        sb.append("out vec4 v_Color;\n");
+        if (key.separateSpecular()) {
+            sb.append("out vec3 v_SpecularColor;\n");
+        }
+        if (key.textureEnabled() || key.hasVertexTexCoord() || key.texGenEnabled()) {
+            sb.append("out vec4 v_TexCoord0;\n");
+        }
+        if (key.lightmapEnabled()) {
+            sb.append("out vec4 v_TexCoord1;\n");
+        }
+        if (key.fogEnabled()) {
+            sb.append("out float v_FogCoord;\n");
+        }
+        sb.append('\n');
+
+        sb.append("void main() {\n");
+        sb.append("    vec4 c0 = gl_in[0].gl_Position;\n");
+        sb.append("    vec4 c1 = gl_in[1].gl_Position;\n\n");
+
+        sb.append("    // NDC positions\n");
+        sb.append("    vec2 n0 = c0.xy / c0.w;\n");
+        sb.append("    vec2 n1 = c1.xy / c1.w;\n\n");
+
+        sb.append("    // Screen-space direction and perpendicular\n");
+        sb.append("    vec2 dir = normalize((n1 - n0) * u_ViewportSize);\n");
+        sb.append("    vec2 offset = vec2(-dir.y, dir.x) * u_LineWidth / u_ViewportSize;\n\n");
+
+        emitVertex(sb, key, 0, "+offset");
+        emitVertex(sb, key, 0, "-offset");
+        emitVertex(sb, key, 1, "+offset");
+        emitVertex(sb, key, 1, "-offset");
+
+        sb.append("    EndPrimitive();\n");
+        sb.append("}\n");
+
+        return sb.toString();
+    }
+
+    private static void emitVertex(StringBuilder sb, VertexKey key, int endpointIdx, String offsetExpr) {
+        final String ci = "c" + endpointIdx;
+        final String ni = "n" + endpointIdx;
+        final String idx = "[" + endpointIdx + "]";
+
+        sb.append("    // Endpoint ").append(endpointIdx).append(' ').append(offsetExpr).append('\n');
+
+        sb.append("    v_Color = v_Color_gs").append(idx).append(";\n");
+        if (key.separateSpecular()) {
+            sb.append("    v_SpecularColor = v_SpecularColor_gs").append(idx).append(";\n");
+        }
+        if (key.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.fogEnabled()) {
+            sb.append("    v_FogCoord = v_FogCoord_gs").append(idx).append(";\n");
+        }
+
+        if (key.clipPlanesEnabled()) {
+            for (int i = 0; i < 8; i++) {
+                sb.append("    gl_ClipDistance[").append(i).append("] = gl_in").append(idx).append(".gl_ClipDistance[").append(i).append("];\n");
+            }
+        }
+
+        sb.append("    gl_Position = vec4((").append(ni).append(' ').append(offsetExpr).append(") * ").append(ci).append(".w, ").append(ci).append(".z, ").append(ci).append(".w);\n");
+        sb.append("    EmitVertex();\n\n");
+    }
+}

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

@@ -0,0 +1,274 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizons.angelica.glsm.GLDebug;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.backend.RenderBackend;
+import lombok.Getter;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL20;
+import org.lwjgl.opengl.GL32;
+import org.lwjgl.opengl.GL40;
+import org.lwjgl.opengl.GL43;
+import org.lwjgl.opengl.KHRDebug;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * A compiled and linked FFP emulation program (vertex + fragment + optional geometry shaders). Owns the GL program handle and caches uniform locations.
+ */
+public class Program {
+
+    private static final AtomicInteger PROGRAM_COUNTER = new AtomicInteger();
+
+    @Getter private final int programId;
+    @Getter private final VertexKey vertexKey;
+    @Getter private final FragmentKey fragmentKey;
+
+    // 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;
+
+    // Current state defaults
+    public int locCurrentNormal = -1;
+    public int locCurrentColor = -1;
+    public int locCurrentTexCoord = -1;
+    public int locCurrentLightmapCoord = -1;
+    public int locLightmapTextureMatrix = -1;
+
+    // Lighting - color material path (raw values)
+    public int locLightModelAmbient = -1;
+    public int locMaterialEmission = -1;
+    public int locMaterialAmbient = -1;
+    public int locMaterialDiffuse = -1;
+    public int locMaterialSpecular = -1;
+    public int locMaterialShininess = -1;
+    public int locLight0Ambient = -1;
+    public int locLight0Diffuse = -1;
+    public int locLight0Specular = -1;
+    public int locLight1Ambient = -1;
+    public int locLight1Diffuse = -1;
+    public int locLight1Specular = -1;
+
+    // Lighting - pre-computed path
+    public int locSceneColor = -1;
+    public int locLightProd0Ambient = -1;
+    public int locLightProd0Diffuse = -1;
+    public int locLightProd0Specular = -1;
+    public int locLightProd1Ambient = -1;
+    public int locLightProd1Diffuse = -1;
+    public int locLightProd1Specular = -1;
+
+    // Light positions
+    public int locLight0Position = -1;
+    public int locLight1Position = -1;
+
+    // Normal scale (for rescale normals)
+    public int locNormalScale = -1;
+
+    // TexGen plane uniforms
+    public int locTexGenObjPlaneS = -1;
+    public int locTexGenObjPlaneT = -1;
+    public int locTexGenObjPlaneR = -1;
+    public int locTexGenObjPlaneQ = -1;
+    public int locTexGenEyePlaneS = -1;
+    public int locTexGenEyePlaneT = -1;
+    public int locTexGenEyePlaneR = -1;
+    public int locTexGenEyePlaneQ = -1;
+
+    // Clip planes
+    public int locClipPlanes = -1;
+
+    // Wide line emulation (geometry shader)
+    public int locViewportSize = -1;
+    public int locLineWidth = -1;
+
+    // Fragment uniforms
+    public final int[] locSampler = { -1, -1, -1, -1 };
+    public int locAlphaRef = -1;
+    public final int[] locTexEnvColor = { -1, -1, -1, -1 };
+    public int locFogParams = -1;
+    public int locFogColor = -1;
+
+    Program(int programId, VertexKey vertexKey, FragmentKey fragmentKey) {
+        this.programId = programId;
+        this.vertexKey = vertexKey;
+        this.fragmentKey = fragmentKey;
+        resolveLocations();
+    }
+
+    private void resolveLocations() {
+        locModelViewMatrix = loc("u_ModelViewMatrix");
+        locProjectionMatrix = loc("u_ProjectionMatrix");
+        locMVPMatrix = loc("u_MVPMatrix");
+        locNormalMatrix = loc("u_NormalMatrix");
+        locTextureMatrix0 = loc("u_TextureMatrix0");
+
+        locCurrentNormal = loc("u_CurrentNormal");
+        locCurrentColor = loc("u_CurrentColor");
+        locCurrentTexCoord = loc("u_CurrentTexCoord");
+        locCurrentLightmapCoord = loc("u_CurrentLightmapCoord");
+        locLightmapTextureMatrix = loc("u_LightmapTextureMatrix");
+
+        // Color material path
+        locLightModelAmbient = loc("u_LightModelAmbient");
+        locMaterialEmission = loc("u_MaterialEmission");
+        locMaterialAmbient = loc("u_MaterialAmbient");
+        locMaterialDiffuse = loc("u_MaterialDiffuse");
+        locMaterialSpecular = loc("u_MaterialSpecular");
+        locMaterialShininess = loc("u_MaterialShininess");
+        locLight0Ambient = loc("u_Light0Ambient");
+        locLight0Diffuse = loc("u_Light0Diffuse");
+        locLight0Specular = loc("u_Light0Specular");
+        locLight1Ambient = loc("u_Light1Ambient");
+        locLight1Diffuse = loc("u_Light1Diffuse");
+        locLight1Specular = loc("u_Light1Specular");
+
+        // Pre-computed path
+        locSceneColor = loc("u_SceneColor");
+        locLightProd0Ambient = loc("u_LightProd0Ambient");
+        locLightProd0Diffuse = loc("u_LightProd0Diffuse");
+        locLightProd0Specular = loc("u_LightProd0Specular");
+        locLightProd1Ambient = loc("u_LightProd1Ambient");
+        locLightProd1Diffuse = loc("u_LightProd1Diffuse");
+        locLightProd1Specular = loc("u_LightProd1Specular");
+
+        // Light positions
+        locLight0Position = loc("u_Light0Position");
+        locLight1Position = loc("u_Light1Position");
+
+        locNormalScale = loc("u_NormalScale");
+
+        // TexGen
+        locTexGenObjPlaneS = loc("u_TexGenObjPlaneS");
+        locTexGenObjPlaneT = loc("u_TexGenObjPlaneT");
+        locTexGenObjPlaneR = loc("u_TexGenObjPlaneR");
+        locTexGenObjPlaneQ = loc("u_TexGenObjPlaneQ");
+        locTexGenEyePlaneS = loc("u_TexGenEyePlaneS");
+        locTexGenEyePlaneT = loc("u_TexGenEyePlaneT");
+        locTexGenEyePlaneR = loc("u_TexGenEyePlaneR");
+        locTexGenEyePlaneQ = loc("u_TexGenEyePlaneQ");
+
+        // Clip planes
+        locClipPlanes = loc("u_ClipPlane[0]");
+
+        // Wide line emulation
+        locViewportSize = loc("u_ViewportSize");
+        locLineWidth = loc("u_LineWidth");
+
+        // Fragment
+        for (int i = 0; i < 4; i++) {
+            locSampler[i] = loc("u_Sampler" + i);
+        }
+        locAlphaRef = loc("u_AlphaRef");
+        for (int i = 0; i < 4; i++) {
+            locTexEnvColor[i] = loc("u_TexEnvColor" + i);
+        }
+        locFogParams = loc("u_FogParams");
+        locFogColor = loc("u_FogColor");
+    }
+
+    private int loc(String name) {
+        return RENDER_BACKEND.getUniformLocation(programId, name);
+    }
+
+    public void destroy() {
+        RENDER_BACKEND.deleteProgram(programId);
+    }
+
+    /**
+     * Compile vertex + fragment + optional geometry shaders, link into a program, and return the FFPProgram.
+     */
+    static Program create(VertexKey vk, FragmentKey fk, String vertSrc, String fragSrc, String geomSrc) {
+        final RenderBackend backend = RENDER_BACKEND;
+        final int id = PROGRAM_COUNTER.getAndIncrement();
+        final String vkHex = Long.toHexString(vk.pack());
+        final boolean hasGeom = geomSrc != null;
+
+        int shaderCount = 0;
+        final int[] shaders = new int[5]; // vertex, fragment, geometry, tess control, tess evaluation
+        int program = 0;
+        try {
+            shaders[shaderCount++] = compileShader(GL20.GL_VERTEX_SHADER, vertSrc, "ffp_v_" + vkHex);
+            shaders[shaderCount++] = compileShader(GL20.GL_FRAGMENT_SHADER, fragSrc, "ffp_f_" + id);
+            if (geomSrc != null) {
+                shaders[shaderCount++] = compileShader(GL32.GL_GEOMETRY_SHADER, geomSrc, "ffp_g_" + id);
+            }
+
+            program = backend.createProgram();
+            for (int i = 0; i < shaderCount; i++) backend.attachShader(program, shaders[i]);
+            backend.linkProgram(program);
+
+            final String log = backend.getProgramInfoLog(program, backend.getProgrami(program, GL20.GL_INFO_LOG_LENGTH));
+            if (!log.isEmpty()) {
+                GLStateManager.LOGGER.warn("FFP program link log (vk=0x{}, fk={}): {}", vkHex, fk, log);
+            }
+
+            if (backend.getProgrami(program, GL20.GL_LINK_STATUS) != GL11.GL_TRUE) {
+                throw new RuntimeException("FFP shader link failed (vk=0x" + vkHex + ", fk=" + fk + "): " + log);
+            }
+
+            final String debugName = "FFP(v=0x" + vkHex + ",f=" + id + (hasGeom ? ",g" : "") + ")";
+            GLDebug.nameObject(KHRDebug.GL_PROGRAM, program, debugName);
+
+            // Detach and delete individual shaders — they're linked into the program
+            for (int i = 0; i < shaderCount; i++) {
+                backend.detachShader(program, shaders[i]);
+                backend.deleteShader(shaders[i]);
+            }
+            shaderCount = 0;
+
+            final Program ffpProgram = new Program(program, vk, fk);
+
+            final int previousProgram = GLStateManager.getActiveProgram();
+            backend.useProgram(program);
+            for (int i = 0; i < 4; i++) {
+                if (ffpProgram.locSampler[i] != -1) backend.uniform1i(ffpProgram.locSampler[i], i);
+            }
+            backend.useProgram(previousProgram);
+
+            return ffpProgram;
+        } catch (RuntimeException e) {
+            if (program != 0) backend.deleteProgram(program);
+            for (int i = 0; i < shaderCount; i++) backend.deleteShader(shaders[i]);
+            throw e;
+        }
+    }
+
+    private static int compileShader(int type, String src, String name) {
+        final RenderBackend backend = RENDER_BACKEND;
+        final int shader = backend.createShader(type);
+        backend.shaderSource(shader, src);
+        backend.compileShader(shader);
+
+        final String typeName = switch (type) {
+            case GL20.GL_VERTEX_SHADER -> "vertex";
+            case GL20.GL_FRAGMENT_SHADER -> "fragment";
+            case GL32.GL_GEOMETRY_SHADER -> "geometry";
+            case GL40.GL_TESS_CONTROL_SHADER -> "tess_control";
+            case GL40.GL_TESS_EVALUATION_SHADER -> "tess_evaluation";
+            case GL43.GL_COMPUTE_SHADER -> "compute";
+            default -> "unknown(0x" + Integer.toHexString(type) + ")";
+        };
+        GLDebug.nameObject(KHRDebug.GL_SHADER, shader, name + "(" + typeName + ")");
+
+        final String log = backend.getShaderInfoLog(shader, backend.getShaderi(shader, GL20.GL_INFO_LOG_LENGTH));
+        if (!log.isEmpty()) {
+            GLStateManager.LOGGER.warn("FFP {} shader compilation log for {}: {}", typeName, name, log);
+        }
+
+        final int result = backend.getShaderi(shader, GL20.GL_COMPILE_STATUS);
+        if (result != GL11.GL_TRUE) {
+            GLStateManager.LOGGER.error("FFP {} shader source:\n{}", typeName, src);
+            backend.deleteShader(shader);
+            throw new RuntimeException("FFP " + typeName + " shader compilation failed for " + name + ": " + log);
+        }
+
+        return shader;
+    }
+}

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

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

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

@@ -0,0 +1,198 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormat;
+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.stacks.Vec3fStack;
+import com.gtnewhorizons.angelica.glsm.stacks.Vec4fStack;
+import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
+import com.gtnewhorizons.angelica.glsm.hooks.GLSMInitConfig;
+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 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();
+    private final Int2IntOpenHashMap vaoVertexFlags = new Int2IntOpenHashMap();
+
+    @Getter
+    private boolean active = false;
+    private Program currentProgram = null;
+    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);
+    @Getter private static final Vector4f currentTexCoord = 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(currentTexCoord);
+    @Getter private static int normalGeneration;
+    @Getter private static int texCoordGeneration;
+    @Getter private boolean enabled = false;
+    private int currentVertexFlags = VertexFlags.TEXTURE_BIT | VertexFlags.COLOR_BIT | VertexFlags.NORMAL_BIT;
+
+    private ShaderManager() {
+        vaoVertexFlags.defaultReturnValue(-1);
+        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;
+
+        VertexFormat.registerSetupBufferStateOverride((format, offset) -> {
+            currentVertexFlags = format.getVertexFlags();
+            vaoVertexFlags.put(GLStateManager.getBoundVAO(), currentVertexFlags);
+            return false;
+        });
+
+        GLStateManager.LOGGER.info("FFP shader emulation enabled");
+    }
+
+    public void disable() {
+        enabled = false;
+    }
+
+    public void activate() {
+        active = true;
+        updateVariant(true, true, true, true);
+        uploadUniforms();
+    }
+
+    public void deactivate() {
+        active = false;
+        currentProgram = null;
+        currentVertexKeyPacked = Long.MIN_VALUE;
+        currentFKLen = 0;
+    }
+
+    public void preDraw(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap) {
+        GLStateManager.flushDeferredVertexAttribs();
+        final DeferredBlendHandler bh = GLSMHooks.blendHandler;
+        if (bh != null) bh.flushDeferredBlend();
+
+        if (!active) {
+            if (enabled) {
+                final int currentProgramId = GLStateManager.getActiveProgram();
+                if (currentProgramId != 0) {
+                    CompatUniformManager.onUseProgram(currentProgramId);
+                    return;
+                }
+                active = true;
+            } else {
+                return;
+            }
+        }
+
+        final long vkPacked = VertexKey.packFromState(hasColor, hasNormal, hasTexCoord, hasLightmap);
+        final int fkLen = FragmentKey.packFromState(currentFKScratch);
+
+        if (vkPacked != currentVertexKeyPacked || !Arrays.equals(currentFKScratch, 0, fkLen, currentFKPacked, 0, currentFKLen)) {
+            commitVariant(vkPacked, fkLen);
+        }
+
+        uploadUniforms();
+    }
+
+    public void preDraw(int vertexFlags) {
+        currentVertexFlags = vertexFlags;
+        preDraw(
+            (vertexFlags & VertexFlags.COLOR_BIT) != 0,
+            (vertexFlags & VertexFlags.NORMAL_BIT) != 0,
+            (vertexFlags & VertexFlags.TEXTURE_BIT) != 0,
+            (vertexFlags & VertexFlags.BRIGHTNESS_BIT) != 0
+        );
+    }
+
+    public void preDraw() {
+        preDraw(currentVertexFlags);
+    }
+
+    private void updateVariant(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap) {
+        final long vkPacked = VertexKey.packFromState(hasColor, hasNormal, hasTexCoord, hasLightmap);
+        final int fkLen = FragmentKey.packFromState(currentFKScratch);
+        commitVariant(vkPacked, fkLen);
+    }
+
+    private void commitVariant(long vkPacked, int fkLen) {
+        currentVertexKeyPacked = vkPacked;
+        System.arraycopy(currentFKScratch, 0, currentFKPacked, 0, fkLen);
+        currentFKLen = fkLen;
+        currentProgram = cache.getOrCreate(vkPacked, currentFKPacked, currentFKLen);
+        RENDER_BACKEND.useProgram(currentProgram.getProgramId());
+    }
+
+    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) {
+        currentTexCoord.set(s, t, r, q);
+        texCoordGeneration++;
+    }
+
+    public static void bumpNormalGeneration() { normalGeneration++; }
+    public static void bumpTexCoordGeneration() { texCoordGeneration++; }
+
+    public void enableClientVertexFlag(int flag) {currentVertexFlags |= flag;}
+    public void disableClientVertexFlag(int flag) {currentVertexFlags &= ~flag;}
+    public int getCurrentVertexFlags() {return currentVertexFlags;}
+    public void setCurrentVertexFlags(int flags) {currentVertexFlags = flags;}
+
+    public void onBindVertexArray(int vaoId) {
+        final int flags = vaoVertexFlags.get(vaoId);
+        if (flags != -1) {
+            currentVertexFlags = flags;
+        }
+    }
+
+    public void onDeleteVertexArray(int vaoId) {
+        vaoVertexFlags.remove(vaoId);
+    }
+
+    public void destroy() {
+        cache.destroy();
+        uniforms.destroy();
+        final GLSMInitConfig config = GLStateManager.getInitConfig();
+        if (config != null && config.getStreamingDrawerDestroy() != null) config.getStreamingDrawerDestroy().run();
+        com.gtnewhorizons.angelica.glsm.QuadConverter.destroy();
+        active = false;
+        currentProgram = null;
+    }
+
+    public String getDebugInfo() {
+        return String.format("FFP: %d programs (%d vert, %d frag variants)",
+            cache.getProgramCount(), cache.getVertexVariantCount(), cache.getFragmentVariantCount());
+    }
+}

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

@@ -0,0 +1,494 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.states.ClipPlaneState;
+import com.gtnewhorizons.angelica.glsm.states.FogState;
+import com.gtnewhorizons.angelica.glsm.states.LightState;
+import com.gtnewhorizons.angelica.glsm.states.MaterialState;
+import com.gtnewhorizons.angelica.glsm.states.TexGenState;
+import com.gtnewhorizons.angelica.glsm.hooks.GLSMConfig;
+import org.joml.Matrix3f;
+import org.joml.Matrix4f;
+import org.joml.Vector4f;
+
+import java.nio.FloatBuffer;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAllocFloat;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memFree;
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * Uploads GLSM cached state to the active FFP program's uniforms.
+ *
+ * Follows Mesa's prog_statevars.c patterns:
+ * - Pre-computed derived state (light products, scene color) when material is static
+ * - Raw light/material values when color material is active
+ * - Optimized fog params (pre-divided for single MAD in shader)
+ */
+public class Uniforms {
+    // Reusable temp buffers for uniform upload
+    private final FloatBuffer mat4Buf = memAllocFloat(16);
+    private final FloatBuffer mat3Buf = memAllocFloat(9);
+    private final FloatBuffer vec4Buf = memAllocFloat(4);
+    private final FloatBuffer vec3Buf = memAllocFloat(3);
+    private final FloatBuffer clipPlaneBuf = memAllocFloat(32); // 8 planes * vec4
+
+    // Derived matrices (computed on CPU)
+    private final Matrix4f mvpMatrix = new Matrix4f();
+    private final Matrix3f normalMatrix = new Matrix3f();
+
+    // Temp vectors for light product and normal scale computation
+    private final Vector4f tempVec4 = new Vector4f();
+    private final org.joml.Vector3f tempVec3 = new org.joml.Vector3f();
+
+    // Pre-computed constants for fog params (Mesa STATE_FOG_PARAMS_OPTIMIZED)
+    private static final double LN2 = 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;
+
+    /**
+     * 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 int mvGen = GLStateManager.mvGeneration;
+        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;
+        if (mvChanged || projChanged || texMatChanged) {
+            uploadMatrices(program, mvChanged, projChanged, texMatChanged);
+            lastMvGen = mvGen;
+            lastProjGen = projGen;
+            lastTexMatGen = texMatGen;
+        }
+
+        if (program.getVertexKey().lightingEnabled()) {
+            final int litGen = GLStateManager.lightingGeneration;
+            if (programChanged || litGen != lastLightingGen) {
+                uploadLighting(program);
+                lastLightingGen = litGen;
+            }
+        }
+
+        // Current color/normal/texcoord — skip if generation unchanged
+        if (!program.getVertexKey().hasVertexColor()) {
+            final int colorGen = GLStateManager.colorGeneration;
+            if (programChanged || colorGen != lastColorGen) {
+                uploadCurrentColor(program);
+                lastColorGen = colorGen;
+            }
+        }
+
+        if (!program.getVertexKey().hasVertexNormal() && program.getVertexKey().lightingEnabled()) {
+            final int normalGen = ShaderManager.getNormalGeneration();
+            if (programChanged || normalGen != lastNormalGen) {
+                uploadCurrentNormal(program);
+                lastNormalGen = normalGen;
+            }
+        }
+
+        if (!program.getVertexKey().hasVertexTexCoord() && program.getVertexKey().textureEnabled()) {
+            final int texGen = ShaderManager.getTexCoordGeneration();
+            if (programChanged || texGen != lastTexCoordGen) {
+                uploadCurrentTexCoord(program);
+                lastTexCoordGen = texGen;
+            }
+        }
+
+        if (program.getVertexKey().lightmapEnabled() && !program.getVertexKey().hasVertexLightmap()) {
+            if (programChanged || GLSMConfig.lastBrightnessX != lastLightmapX || GLSMConfig.lastBrightnessY != lastLightmapY) {
+                uploadCurrentLightmapCoord(program);
+                lastLightmapX = GLSMConfig.lastBrightnessX;
+                lastLightmapY = GLSMConfig.lastBrightnessY;
+            }
+        }
+
+        if (program.getVertexKey().texGenEnabled()) {
+            final int tgGen = GLStateManager.texGenGeneration;
+            if (programChanged || tgGen != lastTexGenGen) {
+                uploadTexGen(program);
+                lastTexGenGen = tgGen;
+            }
+        }
+
+        if (program.getVertexKey().clipPlanesEnabled()) {
+            final int cpGen = GLStateManager.clipPlaneGeneration;
+            if (programChanged || cpGen != lastClipPlaneGen) {
+                uploadClipPlanes(program);
+                lastClipPlaneGen = cpGen;
+            }
+        }
+
+        final int fragGen = GLStateManager.fragmentGeneration;
+        if (programChanged || fragGen != lastFragmentGen) {
+            uploadFragmentUniforms(program);
+            lastFragmentGen = fragGen;
+        }
+
+        // Wide line emulation uniforms
+        if (program.locLineWidth != -1 && program.locViewportSize != -1) {
+            uploadWideLineUniforms(program, programChanged);
+        }
+    }
+
+    private void uploadMatrices(Program program, boolean mvChanged, boolean projChanged, boolean texMatChanged) {
+        final Matrix4f mv = GLStateManager.getModelViewMatrix();
+        final Matrix4f proj = GLStateManager.getProjectionMatrix();
+
+        // ModelView + derived (normal matrix, normal scale)
+        if (mvChanged) {
+            if (program.locModelViewMatrix != -1) {
+                mv.get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(program.locModelViewMatrix, false, mat4Buf);
+            }
+
+            // Normal matrix = inverse transpose of upper-left 3x3 of ModelView
+            if (program.locNormalMatrix != -1 || program.locNormalScale != -1) {
+                mv.normal(normalMatrix);
+            }
+            if (program.locNormalMatrix != -1) {
+                normalMatrix.get(mat3Buf);
+                RENDER_BACKEND.uniformMatrix3(program.locNormalMatrix, false, mat3Buf);
+            }
+
+            // Normal scale (for GL_RESCALE_NORMAL without GL_NORMALIZE)
+            if (program.locNormalScale != -1) {
+                // Scale factor = 1/length of first column of normal matrix
+                final float scale = 1.0f / normalMatrix.getColumn(0, tempVec3).length();
+                RENDER_BACKEND.uniform1f(program.locNormalScale, scale);
+            }
+        }
+
+        // Projection
+        if (projChanged) {
+            if (program.locProjectionMatrix != -1) {
+                proj.get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(program.locProjectionMatrix, false, mat4Buf);
+            }
+        }
+
+        // MVP = Projection * ModelView — needs recompute if either input changed
+        if ((mvChanged || projChanged) && program.locMVPMatrix != -1) {
+            proj.mul(mv, mvpMatrix);
+            mvpMatrix.get(mat4Buf);
+            RENDER_BACKEND.uniformMatrix4(program.locMVPMatrix, false, mat4Buf);
+        }
+
+        // Texture matrices
+        if (texMatChanged) {
+            // Texture matrix unit 0
+            if (program.locTextureMatrix0 != -1) {
+                final Matrix4f texMat = GLStateManager.getTextures().getTextureUnitMatrix(0);
+                texMat.get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(program.locTextureMatrix0, false, mat4Buf);
+            }
+
+            // Texture matrix unit 1 (lightmap)
+            if (program.locLightmapTextureMatrix != -1) {
+                final Matrix4f lmTexMat = GLStateManager.getTextures().getTextureUnitMatrix(1);
+                lmTexMat.get(mat4Buf);
+                RENDER_BACKEND.uniformMatrix4(program.locLightmapTextureMatrix, false, mat4Buf);
+            }
+        }
+    }
+
+    private void uploadLighting(Program program) {
+        final VertexKey vk = program.getVertexKey();
+
+        if (vk.colorMaterialEnabled()) {
+            uploadLightingColorMaterial(program, vk);
+        } else {
+            uploadLightingPreComputed(program, vk);
+        }
+    }
+
+    /**
+     * Color material active: upload raw light and material values.
+     * The shader multiplies them with vertex color at runtime.
+     */
+    private void uploadLightingColorMaterial(Program program, VertexKey vk) {
+        final MaterialState mat = GLStateManager.getFrontMaterial();
+
+        uploadVec4(program.locLightModelAmbient, GLStateManager.getLightModel().ambient);
+        uploadVec4(program.locMaterialEmission, mat.emission);
+        uploadVec4(program.locMaterialAmbient, mat.ambient);
+        uploadVec4(program.locMaterialDiffuse, mat.diffuse);
+        uploadVec4(program.locMaterialSpecular, mat.specular);
+        if (program.locMaterialShininess != -1) {
+            RENDER_BACKEND.uniform1f(program.locMaterialShininess, mat.shininess);
+        }
+
+        if (vk.light0Enabled()) {
+            final LightState light0 = GLStateManager.getLightDataStates()[0];
+            uploadVec4(program.locLight0Ambient, light0.ambient);
+            uploadVec4(program.locLight0Diffuse, light0.diffuse);
+            uploadVec4(program.locLight0Specular, light0.specular);
+            uploadVec4(program.locLight0Position, light0.position);
+        }
+        if (vk.light1Enabled()) {
+            final LightState light1 = GLStateManager.getLightDataStates()[1];
+            uploadVec4(program.locLight1Ambient, light1.ambient);
+            uploadVec4(program.locLight1Diffuse, light1.diffuse);
+            uploadVec4(program.locLight1Specular, light1.specular);
+            uploadVec4(program.locLight1Position, light1.position);
+        }
+    }
+
+    /**
+     * No color material: upload pre-computed light products and scene color.
+     * Fewer shader multiplies since material is static.
+     */
+    private void uploadLightingPreComputed(Program program, VertexKey vk) {
+        final MaterialState mat = GLStateManager.getFrontMaterial();
+
+        // Scene color = emission + ambient * lightModel.ambient
+        // Alpha = material.diffuse.a
+        if (program.locSceneColor != -1) {
+            tempVec4.set(
+                mat.emission.x + mat.ambient.x * GLStateManager.getLightModel().ambient.x,
+                mat.emission.y + mat.ambient.y * GLStateManager.getLightModel().ambient.y,
+                mat.emission.z + mat.ambient.z * GLStateManager.getLightModel().ambient.z,
+                mat.diffuse.w  // alpha from diffuse
+            );
+            uploadVec4(program.locSceneColor, tempVec4);
+        }
+
+        if (program.locMaterialShininess != -1) {
+            RENDER_BACKEND.uniform1f(program.locMaterialShininess, mat.shininess);
+        }
+
+        // Per-light products
+        if (vk.light0Enabled()) {
+            final LightState light0 = GLStateManager.getLightDataStates()[0];
+            uploadVec4(program.locLight0Position, light0.position);
+            uploadLightProduct(program.locLightProd0Ambient, light0.ambient, mat.ambient);
+            uploadLightProduct(program.locLightProd0Diffuse, light0.diffuse, mat.diffuse);
+            uploadLightProduct(program.locLightProd0Specular, light0.specular, mat.specular);
+        }
+        if (vk.light1Enabled()) {
+            final LightState light1 = GLStateManager.getLightDataStates()[1];
+            uploadVec4(program.locLight1Position, light1.position);
+            uploadLightProduct(program.locLightProd1Ambient, light1.ambient, mat.ambient);
+            uploadLightProduct(program.locLightProd1Diffuse, light1.diffuse, mat.diffuse);
+            uploadLightProduct(program.locLightProd1Specular, light1.specular, mat.specular);
+        }
+    }
+
+    /**
+     * Upload pre-multiplied light product: light.X * material.X (RGB only).
+     */
+    private void uploadLightProduct(int loc, Vector4f lightVal, Vector4f materialVal) {
+        if (loc == -1) return;
+        vec3Buf.clear();
+        vec3Buf.put(lightVal.x * materialVal.x);
+        vec3Buf.put(lightVal.y * materialVal.y);
+        vec3Buf.put(lightVal.z * materialVal.z);
+        vec3Buf.flip();
+        RENDER_BACKEND.uniform3(loc, vec3Buf);
+    }
+
+    private void uploadCurrentColor(Program program) {
+        if (program.locCurrentColor == -1) return;
+        // Upload the current color from GLSM
+        final var color = GLStateManager.getColor();
+        vec4Buf.clear();
+        vec4Buf.put(color.getRed());
+        vec4Buf.put(color.getGreen());
+        vec4Buf.put(color.getBlue());
+        vec4Buf.put(color.getAlpha());
+        vec4Buf.flip();
+        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 uploadCurrentLightmapCoord(Program program) {
+        if (program.locCurrentLightmapCoord == -1) return;
+        RENDER_BACKEND.uniform2f(program.locCurrentLightmapCoord,
+            GLSMConfig.lastBrightnessX, GLSMConfig.lastBrightnessY);
+    }
+
+    private void uploadCurrentNormal(Program program) {
+        if (program.locCurrentNormal == -1) return;
+        // Upload current normal from FFPShaderManager's tracked normal
+        final var normal = ShaderManager.getCurrentNormal();
+        vec3Buf.clear();
+        vec3Buf.put(normal.x);
+        vec3Buf.put(normal.y);
+        vec3Buf.put(normal.z);
+        vec3Buf.flip();
+        RENDER_BACKEND.uniform3(program.locCurrentNormal, vec3Buf);
+    }
+
+    private void uploadTexGen(Program program) {
+        final VertexKey vk = program.getVertexKey();
+        final TexGenState tg = GLStateManager.getTextures().getTexGenState(0);
+
+        if (vk.texGenModeS() == VertexKey.TG_OBJ_LINEAR) {
+            uploadPlane(program.locTexGenObjPlaneS, tg.getObjectPlane(org.lwjgl.opengl.GL11.GL_S));
+        } else if (vk.texGenModeS() == VertexKey.TG_EYE_LINEAR) {
+            uploadPlane(program.locTexGenEyePlaneS, tg.getEyePlane(org.lwjgl.opengl.GL11.GL_S));
+        }
+
+        if (vk.texGenModeT() == VertexKey.TG_OBJ_LINEAR) {
+            uploadPlane(program.locTexGenObjPlaneT, tg.getObjectPlane(org.lwjgl.opengl.GL11.GL_T));
+        } else if (vk.texGenModeT() == VertexKey.TG_EYE_LINEAR) {
+            uploadPlane(program.locTexGenEyePlaneT, tg.getEyePlane(org.lwjgl.opengl.GL11.GL_T));
+        }
+
+        if (vk.texGenModeR() == VertexKey.TG_OBJ_LINEAR) {
+            uploadPlane(program.locTexGenObjPlaneR, tg.getObjectPlane(org.lwjgl.opengl.GL11.GL_R));
+        } else if (vk.texGenModeR() == VertexKey.TG_EYE_LINEAR) {
+            uploadPlane(program.locTexGenEyePlaneR, tg.getEyePlane(org.lwjgl.opengl.GL11.GL_R));
+        }
+
+        if (vk.texGenModeQ() == VertexKey.TG_OBJ_LINEAR) {
+            uploadPlane(program.locTexGenObjPlaneQ, tg.getObjectPlane(org.lwjgl.opengl.GL11.GL_Q));
+        } else if (vk.texGenModeQ() == VertexKey.TG_EYE_LINEAR) {
+            uploadPlane(program.locTexGenEyePlaneQ, tg.getEyePlane(org.lwjgl.opengl.GL11.GL_Q));
+        }
+    }
+
+    private void uploadPlane(int loc, float[] plane) {
+        if (loc == -1) return;
+        vec4Buf.clear();
+        vec4Buf.put(plane[0]);
+        vec4Buf.put(plane[1]);
+        vec4Buf.put(plane[2]);
+        vec4Buf.put(plane[3]);
+        vec4Buf.flip();
+        RENDER_BACKEND.uniform4(loc, vec4Buf);
+    }
+
+    private void uploadClipPlanes(Program program) {
+        if (program.locClipPlanes == -1) return;
+        final ClipPlaneState cps = GLStateManager.getClipPlaneState();
+        clipPlaneBuf.clear();
+        for (int i = 0; i < GLStateManager.MAX_CLIP_PLANES; i++) {
+            cps.putEyePlane(i, clipPlaneBuf);
+        }
+        clipPlaneBuf.flip();
+        RENDER_BACKEND.uniform4(program.locClipPlanes, clipPlaneBuf);
+    }
+
+    private void uploadFragmentUniforms(Program program) {
+        final FragmentKey fk = program.getFragmentKey();
+
+        // Alpha test reference
+        if (fk.alphaTestEnabled() && program.locAlphaRef != -1) {
+            RENDER_BACKEND.uniform1f(program.locAlphaRef, GLStateManager.getAlphaState().getReference());
+        }
+
+        // Per-unit tex env color
+        for (int i = 0; i < 4; i++) {
+            if (program.locTexEnvColor[i] != -1) {
+                final var envState = GLStateManager.getTextures().getTexEnvState(i);
+                vec4Buf.clear();
+                vec4Buf.put(envState.envColorR);
+                vec4Buf.put(envState.envColorG);
+                vec4Buf.put(envState.envColorB);
+                vec4Buf.put(envState.envColorA);
+                vec4Buf.flip();
+                RENDER_BACKEND.uniform4(program.locTexEnvColor[i], vec4Buf);
+            }
+        }
+
+        // Fog
+        if (fk.fogMode() != FragmentKey.FOG_NONE) {
+            uploadFog(program);
+        }
+    }
+
+    /**
+     * Upload optimized fog params (following Mesa's STATE_FOG_PARAMS_OPTIMIZED):
+     */
+    private void uploadFog(Program program) {
+        final FogState fog = GLStateManager.getFogState();
+
+        if (program.locFogParams != -1) {
+            final float start = fog.getStart();
+            final float end = fog.getEnd();
+            final float density = fog.getDensity();
+            final float range = end - start;
+
+            vec4Buf.clear();
+            vec4Buf.put(range != 0.0f ? -1.0f / range : 0.0f);     // [0]: -1/(end-start)
+            vec4Buf.put(range != 0.0f ? end / range : 1.0f);         // [1]: end/(end-start)
+            vec4Buf.put((float)(density / LN2));        // [2]: density/ln(2)
+            vec4Buf.put((float)(density / SQRT_LN2));  // [3]: density/sqrt(ln(2))
+            vec4Buf.flip();
+            RENDER_BACKEND.uniform4(program.locFogParams, vec4Buf);
+        }
+
+        if (program.locFogColor != -1) {
+            vec4Buf.clear();
+            vec4Buf.put((float) fog.getFogColor().x);
+            vec4Buf.put((float) fog.getFogColor().y);
+            vec4Buf.put((float) fog.getFogColor().z);
+            vec4Buf.put(fog.getFogAlpha());
+            vec4Buf.flip();
+            RENDER_BACKEND.uniform4(program.locFogColor, vec4Buf);
+        }
+    }
+
+    private void uploadWideLineUniforms(Program program, boolean programChanged) {
+        final float lineWidth = GLStateManager.getLineState().getWidth();
+        if (programChanged || lineWidth != lastLineWidth) {
+            RENDER_BACKEND.uniform1f(program.locLineWidth, lineWidth);
+            lastLineWidth = lineWidth;
+        }
+        final int vw = GLStateManager.getViewportState().width;
+        final int vh = GLStateManager.getViewportState().height;
+        if (programChanged || vw != lastViewportWidth || vh != lastViewportHeight) {
+            RENDER_BACKEND.uniform2f(program.locViewportSize, vw, vh);
+            lastViewportWidth = vw;
+            lastViewportHeight = 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();
+        RENDER_BACKEND.uniform4(loc, vec4Buf);
+    }
+
+    public void destroy() {
+        memFree(mat4Buf);
+        memFree(mat3Buf);
+        memFree(vec4Buf);
+        memFree(vec3Buf);
+        memFree(clipPlaneBuf);
+    }
+}

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

@@ -0,0 +1,265 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizons.angelica.glsm.DisplayListManager;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.states.TexGenState;
+import org.joml.Matrix4f;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL12;
+
+/**
+ * Compact key capturing the vertex shader permutation axes for FFP emulation.
+ * Packed into a single long for fast hash/compare.
+ */
+public final class VertexKey {
+
+    private final long packed;
+
+    private static final int BIT_LIGHTING            = 0;
+    private static final int BIT_LIGHT0              = 1;
+    private static final int BIT_LIGHT1              = 2;
+    private static final int BIT_LIGHT0_DIR          = 3;
+    private static final int BIT_LIGHT1_DIR          = 4;
+    private static final int BIT_COLOR_MATERIAL      = 5;
+    private static final int BIT_SEPARATE_SPECULAR   = 6;
+    private static final int BIT_FOG                 = 7;
+    private static final int BIT_FOG_DIST_MODE       = 8;
+    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;
+
+    public static final int TG_NONE                  = 0;
+    public static final int TG_OBJ_LINEAR            = 1;
+    public static final int TG_EYE_LINEAR            = 2;
+
+    public static final int CM_AMBIENT               = 0;
+    public static final int CM_DIFFUSE               = 1;
+    public static final int CM_SPECULAR              = 2;
+    public static final int CM_EMISSION              = 3;
+    public static final int CM_AMBIENT_AND_DIFFUSE   = 4;
+
+    private VertexKey(long packed) {
+        this.packed = packed;
+    }
+
+    public long pack() { return packed; }
+
+    public boolean lightingEnabled()       { return bit(BIT_LIGHTING); }
+    public boolean light0Enabled()         { return bit(BIT_LIGHT0); }
+    public boolean light1Enabled()         { return bit(BIT_LIGHT1); }
+    public boolean light0Directional()     { return bit(BIT_LIGHT0_DIR); }
+    public boolean light1Directional()     { return bit(BIT_LIGHT1_DIR); }
+    public boolean colorMaterialEnabled()  { return bit(BIT_COLOR_MATERIAL); }
+    public boolean separateSpecular()      { return bit(BIT_SEPARATE_SPECULAR); }
+    public boolean fogEnabled()            { return bit(BIT_FOG); }
+    public int fogDistanceMode()           { return (int)((packed >> BIT_FOG_DIST_MODE) & 0x3); }
+    public boolean normalizeEnabled()      { return bit(BIT_NORMALIZE); }
+    public boolean rescaleNormalsEnabled() { return bit(BIT_RESCALE_NORMAL); }
+    public boolean textureEnabled()        { return bit(BIT_TEXTURE); }
+    public boolean lightmapEnabled()       { return bit(BIT_LIGHTMAP); }
+    public boolean textureMatrixEnabled()  { return bit(BIT_TEX_MATRIX); }
+    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); }
+    /** 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). */
+    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; }
+
+    static int encodeTexGenMode(int glMode) {
+        return switch (glMode) {
+            case GL11.GL_OBJECT_LINEAR -> TG_OBJ_LINEAR;
+            case GL11.GL_EYE_LINEAR -> TG_EYE_LINEAR;
+            default -> TG_NONE;
+        };
+    }
+
+    static int encodeColorMaterialMode(int glMode) {
+        return switch (glMode) {
+            case GL11.GL_AMBIENT -> CM_AMBIENT;
+            case GL11.GL_DIFFUSE -> CM_DIFFUSE;
+            case GL11.GL_SPECULAR -> CM_SPECULAR;
+            case GL11.GL_EMISSION -> CM_EMISSION;
+            case GL11.GL_AMBIENT_AND_DIFFUSE -> CM_AMBIENT_AND_DIFFUSE;
+            default -> CM_AMBIENT_AND_DIFFUSE;
+        };
+    }
+
+    public static long packFromState(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap) {
+        long bits = 0;
+
+        final boolean lighting = GLStateManager.getLightingState().isEnabled();
+        if (lighting) {
+            bits |= (1L << BIT_LIGHTING);
+
+            if (GLStateManager.getLightStates()[0].isEnabled()) {
+                bits |= (1L << BIT_LIGHT0);
+                // position.w == 0 means directional
+                if (GLStateManager.getLightDataStates()[0].position.w == 0.0f) {
+                    bits |= (1L << BIT_LIGHT0_DIR);
+                }
+            }
+            if (GLStateManager.getLightStates()[1].isEnabled()) {
+                bits |= (1L << BIT_LIGHT1);
+                if (GLStateManager.getLightDataStates()[1].position.w == 0.0f) {
+                    bits |= (1L << BIT_LIGHT1_DIR);
+                }
+            }
+
+            if (GLStateManager.getColorMaterial().isEnabled()) {
+                bits |= (1L << BIT_COLOR_MATERIAL);
+                final int cmMode = encodeColorMaterialMode(GLStateManager.getColorMaterialParameter().getValue());
+                bits |= ((long) cmMode & 0x7) << BIT_COLOR_MAT_MODE;
+            }
+
+            if (GLStateManager.getLightModel().colorControl == GL12.GL_SEPARATE_SPECULAR_COLOR) {
+                bits |= (1L << BIT_SEPARATE_SPECULAR);
+            }
+        }
+
+        if (GLStateManager.getFogMode().isEnabled()) {
+            bits |= (1L << BIT_FOG);
+            final int fogDistMode = GLStateManager.getFogState().getFogDistanceMode();
+            bits |= ((long) fogDistMode & 0x3) << BIT_FOG_DIST_MODE;
+        }
+
+        if (GLStateManager.getNormalizeState().isEnabled()) {
+            bits |= (1L << BIT_NORMALIZE);
+        }
+        if (GLStateManager.getRescaleNormalState().isEnabled()) {
+            bits |= (1L << BIT_RESCALE_NORMAL);
+        }
+
+        // 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);
+        }
+
+        // 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();
+        final TexGenState tg = texUnit.getTexGenState(0);
+        boolean anyTexGen = false;
+        if (texUnit.getTexGenSStates(0).isEnabled() && tg.getMode(GL11.GL_S) != 0) {
+            final int m = encodeTexGenMode(tg.getMode(GL11.GL_S));
+            bits |= ((long) m & 0x7) << BIT_TEXGEN_S;
+            if (m != TG_NONE) anyTexGen = true;
+        }
+        if (texUnit.getTexGenTStates(0).isEnabled() && tg.getMode(GL11.GL_T) != 0) {
+            final int m = encodeTexGenMode(tg.getMode(GL11.GL_T));
+            bits |= ((long) m & 0x7) << BIT_TEXGEN_T;
+            if (m != TG_NONE) anyTexGen = true;
+        }
+        if (texUnit.getTexGenRStates(0).isEnabled() && tg.getMode(GL11.GL_R) != 0) {
+            final int m = encodeTexGenMode(tg.getMode(GL11.GL_R));
+            bits |= ((long) m & 0x7) << BIT_TEXGEN_R;
+            if (m != TG_NONE) anyTexGen = true;
+        }
+        if (texUnit.getTexGenQStates(0).isEnabled() && tg.getMode(GL11.GL_Q) != 0) {
+            final int m = encodeTexGenMode(tg.getMode(GL11.GL_Q));
+            bits |= ((long) m & 0x7) << BIT_TEXGEN_Q;
+            if (m != TG_NONE) anyTexGen = true;
+        }
+        // Force texture matrix on when texgen is active (end portal pattern always uses it)
+        if (anyTexGen) {
+            bits |= (1L << BIT_TEX_MATRIX);
+        }
+
+        // Vertex format flags
+        if (hasColor) bits |= (1L << BIT_HAS_VERTEX_COLOR);
+        if (hasNormal) bits |= (1L << BIT_HAS_VERTEX_NORMAL);
+        if (hasTexCoord) bits |= (1L << BIT_HAS_VERTEX_TEX);
+        if (hasLightmap) bits |= (1L << BIT_HAS_VERTEX_LIGHTMAP);
+
+        // Clip planes
+        if (GLStateManager.anyClipPlaneEnabled()) {
+            bits |= (1L << BIT_CLIP_PLANES);
+        }
+
+        // Wide line GS emulation
+        if (GLStateManager.wideLineEmulationActive) {
+            bits |= (1L << BIT_WIDE_LINE);
+        }
+
+        return bits;
+    }
+
+    public static VertexKey fromState(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap) {
+        return new VertexKey(packFromState(hasColor, hasNormal, hasTexCoord, hasLightmap));
+    }
+
+    static VertexKey fromPacked(long packed) {
+        return new VertexKey(packed);
+    }
+
+    @Override
+    public int hashCode() {
+        return Long.hashCode(packed);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (!(obj instanceof VertexKey other)) return false;
+        return packed == other.packed;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("FFPVertexKey[0x%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]",
+            packed, lightingEnabled(), light0Enabled(), light1Enabled(),
+            colorMaterialEnabled(), fogEnabled(), textureEnabled(), lightmapEnabled(),
+            hasVertexColor(), hasVertexNormal(), hasVertexTexCoord(), hasVertexLightmap(),
+            texGenModeS(), texGenModeT(), texGenModeR(), texGenModeQ(), clipPlanesEnabled(), wideLineEmulation());
+    }
+}

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

@@ -0,0 +1,416 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement;
+
+/**
+ * Generates GLSL 330 core vertex shaders for FFP emulation.
+ * Follows Mesa's ffvertex_prog.c build order.
+ *
+ * Attribute locations are sourced from {@link VertexFormatElement.Usage} to stay in sync with GTNHLib's vertex format setup.
+ */
+public final class VertexShaderGenerator {
+
+    private VertexShaderGenerator() {}
+
+    public static String generate(VertexKey key) {
+        final StringBuilder sb = new StringBuilder(2048);
+        sb.append("#version 330 core\n\n");
+
+        emitAttributes(sb, key);
+        emitUniforms(sb, key);
+        emitOutputs(sb, key);
+
+        sb.append("void main() {\n");
+        emitPositionTransform(sb, key);
+        if (key.lightingEnabled()) {
+            emitNormalTransform(sb, key);
+            emitLighting(sb, key);
+        } else {
+            emitColorPassthrough(sb, key);
+        }
+        emitTexCoordPassthrough(sb, key);
+        if (key.fogEnabled()) {
+            emitFogDistance(sb, key);
+        }
+        if (key.clipPlanesEnabled()) {
+            emitClipDistances(sb);
+        }
+        sb.append("}\n");
+
+        String source = sb.toString();
+        if (key.wideLineEmulation()) {
+            source = source.replace("v_SpecularColor", "v_SpecularColor_gs")
+                           .replace("v_TexCoord0", "v_TexCoord0_gs")
+                           .replace("v_TexCoord1", "v_TexCoord1_gs")
+                           .replace("v_FogCoord", "v_FogCoord_gs")
+                           .replace("v_Color", "v_Color_gs");
+        }
+        return source;
+    }
+
+    private static void emitAttributes(StringBuilder sb, VertexKey key) {
+        sb.append("// Vertex attributes\n");
+        sb.append("layout(location = ").append(VertexFormatElement.Usage.POSITION.getAttributeLocation()).append(") in vec3 a_Position;\n");
+        if (key.hasVertexColor()) {
+            sb.append("layout(location = ").append(VertexFormatElement.Usage.COLOR.getAttributeLocation()).append(") in vec4 a_Color;\n");
+        }
+        if (key.hasVertexTexCoord()) {
+            sb.append("layout(location = ").append(VertexFormatElement.Usage.PRIMARY_UV.getAttributeLocation()).append(") in vec2 a_TexCoord0;\n");
+        }
+        if (key.hasVertexLightmap()) {
+            sb.append("layout(location = ").append(VertexFormatElement.Usage.SECONDARY_UV.getAttributeLocation()).append(") in vec2 a_TexCoord1;\n");
+        }
+        if (key.hasVertexNormal()) {
+            sb.append("layout(location = ").append(VertexFormatElement.Usage.NORMAL.getAttributeLocation()).append(") in vec3 a_Normal;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitUniforms(StringBuilder sb, VertexKey key) {
+        sb.append("// Matrices\n");
+        sb.append("uniform mat4 u_ModelViewMatrix;\n");
+        sb.append("uniform mat4 u_ProjectionMatrix;\n");
+        sb.append("uniform mat4 u_MVPMatrix;\n");
+
+        if (key.lightingEnabled()) {
+            sb.append("uniform mat3 u_NormalMatrix;\n");
+        }
+
+        if (key.textureMatrixEnabled()) {
+            sb.append("uniform mat4 u_TextureMatrix0;\n");
+        }
+
+        // TexGen plane uniforms
+        if (key.texGenModeS() == VertexKey.TG_OBJ_LINEAR) sb.append("uniform vec4 u_TexGenObjPlaneS;\n");
+        if (key.texGenModeS() == VertexKey.TG_EYE_LINEAR) sb.append("uniform vec4 u_TexGenEyePlaneS;\n");
+        if (key.texGenModeT() == VertexKey.TG_OBJ_LINEAR) sb.append("uniform vec4 u_TexGenObjPlaneT;\n");
+        if (key.texGenModeT() == VertexKey.TG_EYE_LINEAR) sb.append("uniform vec4 u_TexGenEyePlaneT;\n");
+        if (key.texGenModeR() == VertexKey.TG_OBJ_LINEAR) sb.append("uniform vec4 u_TexGenObjPlaneR;\n");
+        if (key.texGenModeR() == VertexKey.TG_EYE_LINEAR) sb.append("uniform vec4 u_TexGenEyePlaneR;\n");
+        if (key.texGenModeQ() == VertexKey.TG_OBJ_LINEAR) sb.append("uniform vec4 u_TexGenObjPlaneQ;\n");
+        if (key.texGenModeQ() == VertexKey.TG_EYE_LINEAR) sb.append("uniform vec4 u_TexGenEyePlaneQ;\n");
+
+        if (!key.hasVertexNormal() && key.lightingEnabled()) {
+            sb.append("uniform vec3 u_CurrentNormal;\n");
+        }
+
+        if (!key.hasVertexColor()) {
+            sb.append("uniform vec4 u_CurrentColor;\n");
+        }
+
+        if (!key.hasVertexTexCoord() && key.textureEnabled()) {
+            sb.append("uniform vec4 u_CurrentTexCoord;\n");
+        }
+
+        if (key.lightmapEnabled() && !key.hasVertexLightmap()) {
+            sb.append("uniform vec2 u_CurrentLightmapCoord;\n");
+        }
+
+        if (key.lightmapEnabled()) {
+            sb.append("uniform mat4 u_LightmapTextureMatrix;\n");
+        }
+
+        if (key.lightingEnabled()) {
+            emitLightingUniforms(sb, key);
+        }
+
+        if (key.lightingEnabled() && (key.normalizeEnabled() || key.rescaleNormalsEnabled())) {
+            // normalize is done in shader; rescale uses normalScale
+            if (key.rescaleNormalsEnabled() && !key.normalizeEnabled()) {
+                sb.append("uniform float u_NormalScale;\n");
+            }
+        }
+
+        if (key.clipPlanesEnabled()) {
+            sb.append("uniform vec4 u_ClipPlane[8];\n");
+        }
+
+        sb.append('\n');
+    }
+
+    private static void emitLightingUniforms(StringBuilder sb, VertexKey key) {
+        sb.append("\n// Lighting\n");
+
+        if (key.colorMaterialEnabled()) {
+            // When color material is active, we can't pre-compute light products so we upload raw light and material values
+            sb.append("uniform vec4 u_LightModelAmbient;\n");
+            sb.append("uniform vec4 u_MaterialEmission;\n");
+            sb.append("uniform vec4 u_MaterialAmbient;\n");
+            sb.append("uniform vec4 u_MaterialDiffuse;\n");
+            sb.append("uniform vec4 u_MaterialSpecular;\n");
+            sb.append("uniform float u_MaterialShininess;\n");
+
+            if (key.light0Enabled()) {
+                sb.append("uniform vec4 u_Light0Ambient;\n");
+                sb.append("uniform vec4 u_Light0Diffuse;\n");
+                sb.append("uniform vec4 u_Light0Specular;\n");
+                sb.append("uniform vec4 u_Light0Position;\n");
+            }
+            if (key.light1Enabled()) {
+                sb.append("uniform vec4 u_Light1Ambient;\n");
+                sb.append("uniform vec4 u_Light1Diffuse;\n");
+                sb.append("uniform vec4 u_Light1Specular;\n");
+                sb.append("uniform vec4 u_Light1Position;\n");
+            }
+        } else {
+            // Pre-computed: sceneColor + lightProducts
+            sb.append("uniform vec4 u_SceneColor;\n");
+
+            if (key.light0Enabled()) {
+                sb.append("uniform vec4 u_Light0Position;\n");
+                sb.append("uniform vec3 u_LightProd0Ambient;\n");
+                sb.append("uniform vec3 u_LightProd0Diffuse;\n");
+                sb.append("uniform vec3 u_LightProd0Specular;\n");
+            }
+            if (key.light1Enabled()) {
+                sb.append("uniform vec4 u_Light1Position;\n");
+                sb.append("uniform vec3 u_LightProd1Ambient;\n");
+                sb.append("uniform vec3 u_LightProd1Diffuse;\n");
+                sb.append("uniform vec3 u_LightProd1Specular;\n");
+            }
+            sb.append("uniform float u_MaterialShininess;\n");
+        }
+    }
+
+    private static void emitOutputs(StringBuilder sb, VertexKey key) {
+        sb.append("// Outputs\n");
+        sb.append("out vec4 v_Color;\n");
+        if (key.separateSpecular()) {
+            sb.append("out vec3 v_SpecularColor;\n");
+        }
+        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.fogEnabled()) {
+            sb.append("out float v_FogCoord;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitPositionTransform(StringBuilder sb, VertexKey key) {
+        sb.append("  // Position transform\n");
+        sb.append("  vec4 pos4 = vec4(a_Position, 1.0);\n");
+        sb.append("  gl_Position = u_MVPMatrix * pos4;\n");
+
+        // Eye position needed for lighting, fog, EYE_LINEAR texgen, and clip planes
+        if (key.lightingEnabled() || key.fogEnabled() || texGenNeedsEyePos(key) || key.clipPlanesEnabled()) {
+            sb.append("  vec4 eyePos = u_ModelViewMatrix * pos4;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitNormalTransform(StringBuilder sb, VertexKey key) {
+        sb.append("  // Normal transform\n");
+        if (key.hasVertexNormal()) {
+            sb.append("  vec3 normal = u_NormalMatrix * a_Normal;\n");
+        } else {
+            sb.append("  vec3 normal = u_NormalMatrix * u_CurrentNormal;\n");
+        }
+
+        if (key.normalizeEnabled()) {
+            sb.append("  normal = normalize(normal);\n");
+        } else if (key.rescaleNormalsEnabled()) {
+            sb.append("  normal *= u_NormalScale;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitLighting(StringBuilder sb, VertexKey key) {
+        sb.append("  // Gouraud lighting\n");
+
+        if (key.colorMaterialEnabled()) {
+            // Color material: vertex color replaces specific material properties per glColorMaterial mode (Mesa ffvertex_prog.c get_material() bitmask approach)
+            sb.append("  vec4 matColor = ");
+            sb.append(key.hasVertexColor() ? "a_Color" : "u_CurrentColor");
+            sb.append(";\n");
+
+            // Emission source: vertex color for CM_EMISSION, else material uniform
+            final String emSrc = key.cmReplacesEmission() ? "matColor.rgb" : "u_MaterialEmission.rgb";
+            // Ambient source for scene color: vertex color for CM_AMBIENT / CM_AMBIENT_AND_DIFFUSE
+            final String amSrc = key.cmReplacesAmbient() ? "matColor.rgb" : "u_MaterialAmbient.rgb";
+            sb.append("  vec3 sceneColor = ").append(emSrc).append(" + ").append(amSrc).append(" * u_LightModelAmbient.rgb;\n");
+
+            // Alpha from diffuse source (per GL spec)
+            sb.append("  float outAlpha = ").append(key.cmReplacesDiffuse() ? "matColor.a" : "u_MaterialDiffuse.a").append(";\n");
+        } else {
+            // Pre-computed scene color
+            sb.append("  vec3 sceneColor = u_SceneColor.rgb;\n");
+            sb.append("  float outAlpha = u_SceneColor.a;\n");
+        }
+
+        sb.append("  vec3 color0 = sceneColor;\n");
+        if (key.separateSpecular()) {
+            sb.append("  vec3 specAccum = vec3(0.0);\n");
+        }
+
+        // Per-light accumulation
+        if (key.light0Enabled()) {
+            emitLightContribution(sb, key, 0);
+        }
+        if (key.light1Enabled()) {
+            emitLightContribution(sb, key, 1);
+        }
+
+        sb.append("  v_Color = vec4(clamp(color0, 0.0, 1.0), outAlpha);\n");
+        if (key.separateSpecular()) {
+            sb.append("  v_SpecularColor = clamp(specAccum, 0.0, 1.0);\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitLightContribution(StringBuilder sb, VertexKey key, int lightIndex) {
+        final String li = String.valueOf(lightIndex);
+        final boolean directional = (lightIndex == 0) ? key.light0Directional() : key.light1Directional();
+        final String posUniform = "u_Light" + li + "Position";
+
+        sb.append("  { // Light ").append(li).append('\n');
+
+        // Light vector
+        if (directional) {
+            // Directional: position is already normalized direction
+            sb.append("    vec3 VPpli = normalize(").append(posUniform).append(".xyz);\n");
+        } else {
+            // Positional light
+            sb.append("    vec3 VPpli = ").append(posUniform).append(".xyz - eyePos.xyz;\n");
+            sb.append("    VPpli = normalize(VPpli);\n");
+        }
+
+        // Dot products
+        sb.append("    float NdotVP = max(dot(normal, VPpli), 0.0);\n");
+
+        // Half vector for specular (infinite viewer: H = normalize(L + (0,0,1)))
+        sb.append("    vec3 halfVec = normalize(VPpli + vec3(0.0, 0.0, 1.0));\n");
+        sb.append("    float NdotHV = max(dot(normal, halfVec), 0.0);\n");
+
+        // Specular power
+        sb.append("    float spec = (NdotVP > 0.0 && u_MaterialShininess > 0.0) ? pow(NdotHV, u_MaterialShininess) : 0.0;\n");
+
+        // Accumulate — per-property source depends on color material mode
+        if (key.colorMaterialEnabled()) {
+            final String ambU = "u_Light" + li + "Ambient";
+            final String difU = "u_Light" + li + "Diffuse";
+            final String speU = "u_Light" + li + "Specular";
+            // Ambient product: light.ambient * (vertex color or material)
+            final String ambMat = key.cmReplacesAmbient() ? "matColor.rgb" : "u_MaterialAmbient.rgb";
+            sb.append("    vec3 ambient = ").append(ambU).append(".rgb * ").append(ambMat).append(";\n");
+            // Diffuse product
+            final String difMat = key.cmReplacesDiffuse() ? "matColor.rgb" : "u_MaterialDiffuse.rgb";
+            sb.append("    vec3 diffuse = ").append(difU).append(".rgb * ").append(difMat).append(";\n");
+            // Specular product
+            final String speMat = key.cmReplacesSpecular() ? "matColor.rgb" : "u_MaterialSpecular.rgb";
+            sb.append("    vec3 specular = ").append(speU).append(".rgb * ").append(speMat).append(";\n");
+        } else {
+            sb.append("    vec3 ambient = u_LightProd").append(li).append("Ambient;\n");
+            sb.append("    vec3 diffuse = u_LightProd").append(li).append("Diffuse;\n");
+            sb.append("    vec3 specular = u_LightProd").append(li).append("Specular;\n");
+        }
+
+        sb.append("    color0 += ambient + NdotVP * diffuse;\n");
+        if (key.separateSpecular()) {
+            sb.append("    specAccum += spec * specular;\n");
+        } else {
+            sb.append("    color0 += spec * specular;\n");
+        }
+
+        sb.append("  }\n");
+    }
+
+    private static void emitColorPassthrough(StringBuilder sb, VertexKey key) {
+        sb.append("  // Color passthrough (no lighting)\n");
+        if (key.hasVertexColor()) {
+            sb.append("  v_Color = a_Color;\n");
+        } else {
+            sb.append("  v_Color = u_CurrentColor;\n");
+        }
+        sb.append('\n');
+    }
+
+    private static void emitTexCoordPassthrough(StringBuilder sb, VertexKey key) {
+        if (key.texGenEnabled()) {
+            emitTexGenCoordGeneration(sb, key);
+        } else if (key.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.textureMatrixEnabled()) {
+                    sb.append("  v_TexCoord0 = u_TextureMatrix0 * u_CurrentTexCoord;\n");
+                } else {
+                    sb.append("  v_TexCoord0 = u_CurrentTexCoord;\n");
+                }
+            }
+        }
+        if (key.lightmapEnabled()) {
+            if (key.hasVertexLightmap()) {
+                sb.append("  v_TexCoord1 = u_LightmapTextureMatrix * vec4(a_TexCoord1, 0.0, 1.0);\n");
+            } else {
+                sb.append("  v_TexCoord1 = u_LightmapTextureMatrix * vec4(u_CurrentLightmapCoord, 0.0, 1.0);\n");
+            }
+        }
+    }
+
+    /**
+     * Emit per-coordinate texgen code following Mesa's ffvertex_prog.c build order.
+     * OBJ_LINEAR: dot(pos4, objPlane), EYE_LINEAR: dot(eyePos, eyePlane).
+     * Coordinates without texgen use vertex attrib or default (0,0,0,1).
+     */
+    private static void emitTexGenCoordGeneration(StringBuilder sb, VertexKey key) {
+        sb.append("  // TexGen coordinate generation\n");
+        sb.append("  vec4 texGenCoord = vec4(0.0, 0.0, 0.0, 1.0);\n");
+
+        emitTexGenComponent(sb, key.texGenModeS(), "s", "S", key);
+        emitTexGenComponent(sb, key.texGenModeT(), "t", "T", key);
+        emitTexGenComponent(sb, key.texGenModeR(), "r", "R", key);
+        emitTexGenComponent(sb, key.texGenModeQ(), "q", "Q", key);
+
+        // Always apply texture matrix when texgen is active (forced on in VertexKey)
+        sb.append("  v_TexCoord0 = u_TextureMatrix0 * texGenCoord;\n");
+    }
+
+    private static void emitTexGenComponent(StringBuilder sb, int mode, String swizzle, String coordName, VertexKey key) {
+        switch (mode) {
+            case VertexKey.TG_OBJ_LINEAR ->
+                sb.append("  texGenCoord.").append(swizzle).append(" = dot(pos4, u_TexGenObjPlane").append(coordName).append(");\n");
+            case VertexKey.TG_EYE_LINEAR ->
+                sb.append("  texGenCoord.").append(swizzle).append(" = dot(eyePos, u_TexGenEyePlane").append(coordName).append(");\n");
+            // TG_NONE: keep default (0 for s/t/r, 1 for q) — already set in texGenCoord init
+        }
+    }
+
+    private static boolean texGenNeedsEyePos(VertexKey key) {
+        return key.texGenModeS() == VertexKey.TG_EYE_LINEAR
+            || key.texGenModeT() == VertexKey.TG_EYE_LINEAR
+            || key.texGenModeR() == VertexKey.TG_EYE_LINEAR
+            || key.texGenModeQ() == VertexKey.TG_EYE_LINEAR;
+    }
+
+    private static void emitFogDistance(StringBuilder sb, VertexKey key) {
+        sb.append("  // Fog distance\n");
+        // Mesa ffvertex_prog.c build_fog(): FDM_EYE_RADIAL/EYE_PLANE/EYE_PLANE_ABS
+        final int fogDistMode = key.fogDistanceMode();
+        switch (fogDistMode) {
+            case 0 -> // FDM_EYE_RADIAL: Euclidean distance
+                sb.append("  v_FogCoord = length(eyePos.xyz);\n");
+            case 1 -> // FDM_EYE_PLANE: raw Z (can be negative, clamped by fog factor)
+                sb.append("  v_FogCoord = eyePos.z;\n");
+            case 2 -> // FDM_EYE_PLANE_ABS: absolute Z
+                sb.append("  v_FogCoord = abs(eyePos.z);\n");
+            default ->
+                sb.append("  v_FogCoord = abs(eyePos.z);\n");
+        }
+    }
+
+    private static void emitClipDistances(StringBuilder sb) {
+        sb.append("  // Clip distances\n");
+        for (int i = 0; i < 8; i++) {
+            sb.append("  gl_ClipDistance[").append(i).append("] = dot(u_ClipPlane[").append(i).append("], eyePos);\n");
+        }
+    }
+}

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

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

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

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

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

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

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

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

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

@@ -0,0 +1,37 @@
+package com.gtnewhorizons.angelica.glsm.hooks;
+
+import com.gtnewhorizons.angelica.glsm.hooks.events.BlendFuncChangeEvent;
+import com.gtnewhorizons.angelica.glsm.hooks.events.FogStateChangeEvent;
+import com.gtnewhorizons.angelica.glsm.hooks.events.LightmapCoordsEvent;
+import com.gtnewhorizons.angelica.glsm.hooks.events.ProgramChangeEvent;
+import com.gtnewhorizons.angelica.glsm.hooks.events.TextureBindEvent;
+import com.gtnewhorizons.angelica.glsm.hooks.events.TextureDeleteEvent;
+import com.gtnewhorizons.angelica.glsm.hooks.events.TextureUnitStateEvent;
+import net.minecraftforge.eventbus.api.bus.EventBus;
+
+public final class GLSMHooks {
+
+    public static DeferredBlendHandler blendHandler;
+    public static DeferredAlphaHandler alphaHandler;
+    public static DeferredDepthColorHandler depthColorHandler;
+
+    // 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);
+
+    // 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();
+
+    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 boolean framebufferSupported;
+    private final boolean fboEnabled;
+    private final Consumer<DirectTessellator> directDrawer;
+    private final Runnable streamingDrawerDestroy;
+    private final int displayWidth;
+    private final int displayHeight;
+    private final Runnable postInitCallback;
+
+    private GLSMInitConfig(Builder builder) {
+        this.lwjglDebug = builder.lwjglDebug;
+        this.streamingUploadStrategy = builder.streamingUploadStrategy;
+        this.framebufferSupported = builder.framebufferSupported;
+        this.fboEnabled = builder.fboEnabled;
+        this.directDrawer = builder.directDrawer;
+        this.streamingDrawerDestroy = builder.streamingDrawerDestroy;
+        this.displayWidth = builder.displayWidth;
+        this.displayHeight = builder.displayHeight;
+        this.postInitCallback = builder.postInitCallback;
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public boolean isLwjglDebug() { return lwjglDebug; }
+    public StreamingUploader.UploadStrategy getStreamingUploadStrategy() { return streamingUploadStrategy; }
+    public boolean isFramebufferSupported() { return framebufferSupported; }
+    public boolean isFboEnabled() { return fboEnabled; }
+    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 static final class Builder {
+        private boolean lwjglDebug = false;
+        private StreamingUploader.UploadStrategy streamingUploadStrategy = StreamingUploader.UploadStrategy.BUFFER_DATA;
+        private boolean framebufferSupported = false;
+        private boolean fboEnabled = false;
+        private Consumer<DirectTessellator> directDrawer = null;
+        private Runnable streamingDrawerDestroy = null;
+        private int displayWidth = 0;
+        private int displayHeight = 0;
+        private Runnable postInitCallback = null;
+
+        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 framebufferSupported(boolean framebufferSupported) {
+            this.framebufferSupported = framebufferSupported;
+            return this;
+        }
+
+        public Builder fboEnabled(boolean fboEnabled) {
+            this.fboEnabled = fboEnabled;
+            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 GLSMInitConfig build() {
+            return new GLSMInitConfig(this);
+        }
+    }
+}

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 +1,8 @@
+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;
+}

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/recording/AccumulatedDraw.java

@@ -0,0 +1,64 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.DirectTessellator;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormat;
+
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Represents an accumulated draw call during display list compilation.
+ * Matrix-as-Data Architecture: Stores untransformed vertices + captured matrix.
+ * The matrix will be applied at runtime, not baked into vertices.
+ */
+public final class AccumulatedDraw {
+    public final VertexFormat format;
+    public final List<ByteBuffer> drawBuffers;
+    public final int drawMode;
+    public 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) {
+        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);
+        }
+    }
+
+
+    public void mergeDraw(DirectTessellator tessellator, boolean copyLast) {
+        this.drawBuffers.add(tessellator.allocateBufferCopy());
+
+        if (copyLast) {
+            this.restoreData = new RestoreData(tessellator);
+        }
+    }
+
+    /**
+     * Holds last vertex attribute values for GL state restoration after VBO draw.
+     * Used to sync GLSM cache with actual GL state after VBO rendering.
+     */
+    public static final class RestoreData {
+        public final int lastColor;
+        public final int lastNormal;
+        public final float lastTexCoordU;
+        public final float lastTexCoordV;
+        public final int flags;
+
+        public RestoreData(DirectTessellator tessellator) {
+            this.lastColor = tessellator.getPackedColor();
+            this.lastNormal = tessellator.getPackedNormal();
+            this.lastTexCoordU = (float) tessellator.getLastTextureU();
+            this.lastTexCoordV = (float) tessellator.getLastTextureV();
+            this.flags = tessellator.getVertexFormat().getVertexFlags();
+        }
+    }
+}

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

@@ -14,12 +14,6 @@ import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.*;
 public final class CommandBuffer {
     private static final int DEFAULT_CAPACITY = 4096; // Guess at typical display list size
 
-    // Flag bits for DRAW_RANGE_RESTORE command
-    public static final int FLAG_HAS_BRIGHTNESS = 1 << 0;
-    public static final int FLAG_HAS_COLOR      = 1 << 1;
-    public static final int FLAG_HAS_NORMALS    = 1 << 2;
-    public static final int FLAG_HAS_TEXTURE    = 1 << 3;
-
     private ByteBuffer buffer;
     private long basePointer;
     private long writePointer;
@@ -42,6 +36,11 @@ public final class CommandBuffer {
         writePointer += 4;
     }
 
+    private void writeLong(long value) {
+        memPutLong(writePointer, value);
+        writePointer += 8;
+    }
+
     private void writeFloat(float value) {
         memPutFloat(writePointer, value);
         writePointer += 4;
@@ -264,6 +263,15 @@ public final class CommandBuffer {
         writeInt(height);
     }
 
+    public void writeScissor(int x, int y, int width, int height) {
+        ensureCapacity(20);
+        writeInt(GLCommand.SCISSOR);
+        writeInt(x);
+        writeInt(y);
+        writeInt(width);
+        writeInt(height);
+    }
+
     public void writeBlendFunc(int srcRgb, int dstRgb, int srcAlpha, int dstAlpha) {
         ensureCapacity(20);
         writeInt(GLCommand.BLEND_FUNC);
@@ -546,15 +554,22 @@ public final class CommandBuffer {
         }
     }
 
+    public void writeClipPlane(int plane, double a, double b, double c, double d) {
+        ensureCapacity(40);
+        writeInt(GLCommand.CLIP_PLANE);
+        writeInt(plane);
+        writeDouble(a);
+        writeDouble(b);
+        writeDouble(c);
+        writeDouble(d);
+    }
+
     // === Draw commands ===
 
-    public void writeDrawRange(int vboIndex, int startVertex, int vertexCount, boolean hasBrightness) {
-        ensureCapacity(20);
+    public void writeDrawRange(int vboIndex) {
+        ensureCapacity(8);
         writeInt(GLCommand.DRAW_RANGE);
         writeInt(vboIndex);
-        writeInt(startVertex);
-        writeInt(vertexCount);
-        writeInt(hasBrightness ? 1 : 0);
     }
 
     /**
@@ -562,51 +577,21 @@ public final class CommandBuffer {
      * Used for immediate mode VBOs to restore GL_CURRENT_COLOR, GL_CURRENT_NORMAL, GL_CURRENT_TEXTURE_COORDS.
      *
      * @param vboIndex Index into ownedVbos array
-     * @param startVertex First vertex to draw
-     * @param vertexCount Number of vertices to draw
-     * @param hasBrightness True if VBO has brightness/lightmap data
-     * @param hasColor True if color should be restored after draw
-     * @param hasNormals True if normal should be restored after draw
-     * @param hasTexture True if texcoord should be restored after draw
-     * @param lastColorR Last vertex's red color component
-     * @param lastColorG Last vertex's green color component
-     * @param lastColorB Last vertex's blue color component
-     * @param lastColorA Last vertex's alpha color component
-     * @param lastNormalX Last vertex's normal X
-     * @param lastNormalY Last vertex's normal Y
-     * @param lastNormalZ Last vertex's normal Z
-     * @param lastTexS Last vertex's texture S coordinate
-     * @param lastTexT Last vertex's texture T coordinate
      */
     public void writeDrawRangeRestore(
-        int vboIndex, int startVertex, int vertexCount,
-        boolean hasBrightness, boolean hasColor, boolean hasNormals, boolean hasTexture,
-        float lastColorR, float lastColorG, float lastColorB, float lastColorA,
-        float lastNormalX, float lastNormalY, float lastNormalZ,
-        float lastTexS, float lastTexT
+        int vboIndex, AccumulatedDraw.RestoreData restoreData
     ) {
-        ensureCapacity(56);
+        ensureCapacity(28);
         writeInt(GLCommand.DRAW_RANGE_RESTORE);
         writeInt(vboIndex);
-        writeInt(startVertex);
-        writeInt(vertexCount);
-        int flags = (hasBrightness ? FLAG_HAS_BRIGHTNESS : 0)
-                  | (hasColor ? FLAG_HAS_COLOR : 0)
-                  | (hasNormals ? FLAG_HAS_NORMALS : 0)
-                  | (hasTexture ? FLAG_HAS_TEXTURE : 0);
-        writeInt(flags);
-        // Last color (4 floats = 16 bytes)
-        writeFloat(lastColorR);
-        writeFloat(lastColorG);
-        writeFloat(lastColorB);
-        writeFloat(lastColorA);
-        // Last normal (3 floats = 12 bytes)
-        writeFloat(lastNormalX);
-        writeFloat(lastNormalY);
-        writeFloat(lastNormalZ);
+        writeInt(restoreData.flags);
+        // Last color (4 bytes)
+        writeInt(restoreData.lastColor);
+        // Last normal (4 bytes)
+        writeInt(restoreData.lastNormal);
         // Last texcoord (2 floats = 8 bytes)
-        writeFloat(lastTexS);
-        writeFloat(lastTexT);
+        writeFloat(restoreData.lastTexCoordU);
+        writeFloat(restoreData.lastTexCoordV);
     }
 
     public void writeCallList(int listId) {
@@ -615,6 +600,35 @@ public final class CommandBuffer {
         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);
+        writeInt(vbo);
+    }
+
+    public void writeBindVAO(int vao) {
+        ensureCapacity(8);
+        writeInt(GLCommand.BIND_VAO);
+        writeInt(vao);
+    }
+
     public void writeDrawBuffer(int mode) {
         ensureCapacity(8);
         writeInt(GLCommand.DRAW_BUFFER);
@@ -685,6 +699,12 @@ public final class CommandBuffer {
         return value;
     }
 
+    public long readLong() {
+        final long value = memGetLong(readPointer);
+        readPointer += 8;
+        return value;
+    }
+
     /**
      * Read a float from the current position.
      */

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

@@ -1,17 +1,20 @@
 package com.gtnewhorizons.angelica.glsm.recording;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.vbo.VertexBuffer;
+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;
+import java.nio.DoubleBuffer;
 import java.nio.FloatBuffer;
 import java.nio.IntBuffer;
 
 import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.*;
-import static com.gtnewhorizons.angelica.glsm.recording.CommandBuffer.*;
 
 /**
  * Executes commands from a CommandBuffer
@@ -23,6 +26,8 @@ public final class CommandBufferExecutor {
     private static final FloatBuffer MATRIX_BUFFER = BufferUtils.createFloatBuffer(16);
     // Static reusable buffer for fog/light/material params
     private static final FloatBuffer PARAMS_BUFFER = BufferUtils.createFloatBuffer(4);
+    // Static reusable buffer for clip plane equation
+    private static final DoubleBuffer PARAMS_DOUBLE_BUFFER = BufferUtils.createDoubleBuffer(4);
     // Static reusable buffer for draw buffers
     private static final int MAX_DRAW_BUFFERS = 8;
     private static final IntBuffer DRAW_BUFFERS_BUFFER = BufferUtils.createIntBuffer(MAX_DRAW_BUFFERS);
@@ -34,7 +39,7 @@ 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, VertexBuffer[] ownedVbos) {
+    public static void execute(ByteBuffer buffer, Object[] complexObjects, DisplayListVBO ownedVbos) {
         long ptr = memAddress(buffer);
         final long end = ptr + buffer.limit();
 
@@ -194,6 +199,14 @@ public final class CommandBufferExecutor {
                     ptr += 16;
                     GLStateManager.glViewport(x, y, width, height);
                 }
+                case GLCommand.SCISSOR -> {
+                    final int x = memGetInt(ptr);
+                    final int y = memGetInt(ptr + 4);
+                    final int width = memGetInt(ptr + 8);
+                    final int height = memGetInt(ptr + 12);
+                    ptr += 16;
+                    GLStateManager.glScissor(x, y, width, height);
+                }
                 case GLCommand.BLEND_FUNC -> {
                     final int srcRgb = memGetInt(ptr);
                     final int dstRgb = memGetInt(ptr + 4);
@@ -447,51 +460,55 @@ public final class CommandBufferExecutor {
                     GLStateManager.glMaterial(face, pname, PARAMS_BUFFER);
                 }
 
+                case GLCommand.CLIP_PLANE -> {
+                    final int plane = memGetInt(ptr);
+                    final double a = memGetDouble(ptr + 4);
+                    final double b = memGetDouble(ptr + 12);
+                    final double c = memGetDouble(ptr + 20);
+                    final double d = memGetDouble(ptr + 28);
+                    ptr += 36;
+                    PARAMS_DOUBLE_BUFFER.clear();
+                    PARAMS_DOUBLE_BUFFER.put(a).put(b).put(c).put(d);
+                    PARAMS_DOUBLE_BUFFER.flip();
+                    GLStateManager.glClipPlane(plane, PARAMS_DOUBLE_BUFFER);
+                }
+
                 // === Draw commands ===
                 case GLCommand.DRAW_RANGE -> {
                     final int vboIndex = memGetInt(ptr);
-                    final int start = memGetInt(ptr + 4);
-                    final int count = memGetInt(ptr + 8);
-                    final boolean hasBrightness = memGetInt(ptr + 12) != 0;
-                    ptr += 16;
-                    final VertexBuffer vbo = ownedVbos[vboIndex];
-                    vbo.setupState();
-                    vbo.draw(start, count);
-                    vbo.cleanupState();
+                    ptr += 4;
+                    ownedVbos.render(vboIndex);
                 }
                 case GLCommand.DRAW_RANGE_RESTORE -> {
                     // Draw VBO range then restore GL current state from last vertex attributes
                     final int vboIndex = memGetInt(ptr);
-                    final int start = memGetInt(ptr + 4);
-                    final int count = memGetInt(ptr + 8);
-                    final int flags = memGetInt(ptr + 12);
+                    final int flags = memGetInt(ptr + 4);
 
                     // Draw the VBO
-                    final VertexBuffer vbo = ownedVbos[vboIndex];
-                    vbo.setupState();
-                    vbo.draw(start, count);
-                    vbo.cleanupState();
+                    ownedVbos.render(vboIndex);
 
                     // Restore attributes based on flags
-                    if ((flags & FLAG_HAS_COLOR) != 0) {
-                        final float r = memGetFloat(ptr + 16);
-                        final float g = memGetFloat(ptr + 20);
-                        final float b = memGetFloat(ptr + 24);
-                        final float a = memGetFloat(ptr + 28);
-                        GLStateManager.glColor4f(r, g, b, a);
+                    if ((flags & VertexFlags.COLOR_BIT) != 0) {
+                        final int color = memGetInt(ptr + 8);
+                        final byte a = (byte) ((color >> 24) & 0xFF);
+                        final byte b = (byte) ((color >> 16) & 0xFF);
+                        final byte g = (byte) ((color >> 8) & 0xFF);
+                        final byte r = (byte) ((color & 0xFF));
+                        GLStateManager.glColor4ub(r, g, b, a);
                     }
-                    if ((flags & FLAG_HAS_NORMALS) != 0) {
-                        final float nx = memGetFloat(ptr + 32);
-                        final float ny = memGetFloat(ptr + 36);
-                        final float nz = memGetFloat(ptr + 40);
+                    if ((flags & VertexFlags.NORMAL_BIT) != 0) {
+                        final int normal = memGetInt(ptr + 12);
+                        float nx = (byte)(normal)       / 127.0f;
+                        float ny = (byte)(normal >> 8)  / 127.0f;
+                        float nz = (byte)(normal >> 16) / 127.0f;
                         GLStateManager.glNormal3f(nx, ny, nz);
                     }
-                    if ((flags & FLAG_HAS_TEXTURE) != 0) {
-                        final float s = memGetFloat(ptr + 44);
-                        final float t = memGetFloat(ptr + 48);
+                    if ((flags & VertexFlags.TEXTURE_BIT) != 0) {
+                        final float s = memGetFloat(ptr + 16);
+                        final float t = memGetFloat(ptr + 20);
                         GLStateManager.glTexCoord2f(s, t);
                     }
-                    ptr += 52;  // Skip full command size (56 - 4 for cmd already read)
+                    ptr += 24;  // Skip full command size (28 - 4 for cmd already read)
                 }
                 case GLCommand.CALL_LIST -> {
                     final int listId = memGetInt(ptr);
@@ -513,6 +530,22 @@ 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;
+                }
+                case GLCommand.BIND_VAO -> {
+                    GLStateManager.glBindVertexArray(memGetInt(ptr));
+                    ptr += 4;
+                }
 
                 // === Complex object reference ===
                 case GLCommand.COMPLEX_REF -> {

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

@@ -1,89 +1,16 @@
 package com.gtnewhorizons.angelica.glsm.recording;
 
-import com.gtnewhorizons.angelica.glsm.DisplayListManager;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.recording.commands.DisplayListCommand;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.joml.Matrix4f;
-import org.lwjgl.opengl.GL11;
 
 import java.nio.FloatBuffer;
-import java.util.ArrayDeque;
-import java.util.Deque;
 
 public final class CommandBufferProcessor {
-    private static final Logger LOGGER = LogManager.getLogger("CommandBufferProcessor");
     private static final Matrix4f tempMatrix = new Matrix4f();
 
     private CommandBufferProcessor() {}
 
-    public static void processCommandForOptimization(int opcode, CommandBuffer raw, BufferTransformOptimizer opt, CommandBuffer out) {
-        switch (opcode) {
-            // === MultMatrix - already collapsed transforms from flushMatrix() ===
-            case GLCommand.MULT_MATRIX -> {
-                raw.readMatrix4f(tempMatrix);
-                opt.multMatrix(tempMatrix);          // accumulated = accumulated * tempMatrix
-                out.writeMultMatrix(tempMatrix);     // Copy to output
-                opt.markLastEmittedAsAccumulated();  // lastEmitted = accumulated (what GL now has)
-            }
-
-            // === Load commands - flush pending, emit, reset accumulator ===
-            case GLCommand.LOAD_IDENTITY -> {
-                opt.emitPendingTransform(out);     // Emit any pending transforms first
-                out.writeLoadIdentity();           // Always emit LoadIdentity
-                opt.loadIdentity();                // Reset accumulated to identity
-                opt.resetLastEmitted();            // Reset lastEmitted to identity
-                opt.checkAndClearAbsoluteMatrix(); // Clear the flag if set
-            }
-            case GLCommand.LOAD_MATRIX -> {
-                raw.readMatrix4f(tempMatrix);
-                opt.emitPendingTransform(out);
-                out.writeLoadMatrix(tempMatrix);
-                opt.loadIdentity();
-                opt.resetLastEmitted();  // Reset lastEmitted to identity
-                opt.markAbsoluteMatrix();
-            }
-
-            // === Stack operations - flush/update optimizer state and copy ===
-            case GLCommand.PUSH_MATRIX -> {
-                opt.emitPendingTransform(out);
-                opt.push();
-                // Reset accumulated/lastEmitted to identity after push.
-                opt.loadIdentity();
-                opt.resetLastEmitted();
-                out.writePushMatrix();
-            }
-            case GLCommand.POP_MATRIX -> {
-                opt.pop();
-                out.writePopMatrix();
-            }
-
-            // === Barriers - emit pending transform before copying ===
-            case GLCommand.MATRIX_MODE -> {
-                final int mode = raw.readInt();
-                opt.emitPendingTransform(out);  // Pending transforms apply to OLD mode
-                out.writeMatrixMode(mode);
-                opt.loadIdentity();             // Reset accumulated for new mode
-                opt.resetLastEmitted();         // Reset lastEmitted for new mode
-            }
-            case GLCommand.CALL_LIST -> {
-                final int listId = raw.readInt();
-                opt.emitPendingTransform(out);
-                out.writeCallList(listId);
-            }
-            case GLCommand.PUSH_ATTRIB -> {
-                final int mask = raw.readInt();
-                if ((mask & GL11.GL_TRANSFORM_BIT) != 0) {
-                    opt.emitPendingTransform(out);
-                }
-                out.writePushAttrib(mask);
-            }
-
-            // === All other commands - just copy ===
-            default -> copyCommandData(opcode, raw, out);
-        }
-    }
-
     /**
      * Copy a complete command (opcode already read) from raw to final buffer.
      */
@@ -134,6 +61,7 @@ public final class CommandBufferProcessor {
 
             // Four int commands
             case GLCommand.VIEWPORT -> out.writeViewport(raw.readInt(), raw.readInt(), raw.readInt(), raw.readInt());
+            case GLCommand.SCISSOR -> out.writeScissor(raw.readInt(), raw.readInt(), raw.readInt(), raw.readInt());
             case GLCommand.BLEND_FUNC -> out.writeBlendFunc(raw.readInt(), raw.readInt(), raw.readInt(), raw.readInt());
             case GLCommand.COLOR_MASK -> out.writeColorMask(raw.readInt() != 0, raw.readInt() != 0, raw.readInt() != 0, raw.readInt() != 0);
             case GLCommand.STENCIL_FUNC_SEPARATE -> out.writeStencilFuncSeparate(raw.readInt(), raw.readInt(), raw.readInt(), raw.readInt());
@@ -209,9 +137,23 @@ public final class CommandBufferProcessor {
                 out.writeMaterial(face, pname, fb);
             }
 
+            // Clip plane command (4 doubles)
+            case GLCommand.CLIP_PLANE -> {
+                final int plane = raw.readInt();
+                final double a = raw.readDouble();
+                final double b = raw.readDouble();
+                final double c = raw.readDouble();
+                final double d = raw.readDouble();
+                out.writeClipPlane(plane, a, b, c, d);
+            }
+
             // Draw/call commands
-            case GLCommand.DRAW_RANGE -> out.writeDrawRange(raw.readInt(), raw.readInt(), raw.readInt(), raw.readInt() != 0);
+            case GLCommand.DRAW_RANGE -> out.writeDrawRange(raw.readInt());
             case GLCommand.CALL_LIST -> out.writeCallList(raw.readInt());
+            case GLCommand.DRAW_ARRAYS -> out.writeDrawArrays(raw.readInt(), raw.readInt(), raw.readInt());
+            case GLCommand.DRAW_ELEMENTS -> out.writeDrawElements(raw.readInt(), raw.readInt(), raw.readInt(), raw.readLong());
+            case GLCommand.BIND_VBO -> out.writeBindVBO(raw.readInt());
+            case GLCommand.BIND_VAO -> out.writeBindVAO(raw.readInt());
 
             // Complex object reference - transfer the object to output buffer
             case GLCommand.COMPLEX_REF -> {
@@ -220,97 +162,7 @@ public final class CommandBufferProcessor {
                 out.writeComplexRef((DisplayListCommand) obj);
             }
 
-            default -> LOGGER.warn("[CommandBufferProcessor] Unknown opcode in buffer copy: {}", opcode);
-        }
-    }
-
-    /**
-     * Lightweight transform optimizer for buffer-to-buffer processing.
-     * Tracks accumulated transform (mode-agnostic) and emits MultMatrix commands when needed.
-     *
-     * <p>This optimizer processes raw transform commands (TRANSLATE, ROTATE, SCALE) and
-     * collapses them into single MultMatrix commands at barriers. It must stay synchronized
-     * with the relativeTransform tracking in DisplayListManager - both systems must reset
-     * at the same barriers (MatrixMode, LoadIdentity, LoadMatrix, Push/Pop).</p>
-     */
-    public static class BufferTransformOptimizer {
-        private final Matrix4f accumulated = new Matrix4f();
-        private final Matrix4f lastEmitted = new Matrix4f();
-        private final Matrix4f delta = new Matrix4f();  // Reused for delta computation
-        private final Deque<Matrix4f> stack = new ArrayDeque<>();
-        private boolean absoluteMatrixFlag = false;
-
-        public BufferTransformOptimizer() {
-            accumulated.identity();
-            lastEmitted.identity();
-        }
-
-        public void multMatrix(Matrix4f m) {
-            accumulated.mul(m);
-        }
-
-        public void loadIdentity() {
-            accumulated.identity();
-        }
-
-        public void push() {
-            stack.push(new Matrix4f(accumulated));
-        }
-
-        public void pop() {
-            if (!stack.isEmpty()) {
-                accumulated.set(stack.pop());
-                lastEmitted.set(accumulated);
-            } else {
-                accumulated.identity();
-                lastEmitted.identity();
-            }
-        }
-
-        public boolean isIdentity() {
-            return DisplayListManager.isIdentity(accumulated);
-        }
-
-        public void markAbsoluteMatrix() {
-            absoluteMatrixFlag = true;
-        }
-
-        public boolean checkAndClearAbsoluteMatrix() {
-            final boolean was = absoluteMatrixFlag;
-            absoluteMatrixFlag = false;
-            return was;
-        }
-
-        public void resetLastEmitted() {
-            lastEmitted.identity();
-        }
-
-        public void setLastEmitted(Matrix4f m) {
-            lastEmitted.set(m);
-        }
-
-        public void markLastEmittedAsAccumulated() {
-            lastEmitted.set(accumulated);
-        }
-
-        public void emitPendingTransform(CommandBuffer out) {
-            if (!accumulated.equals(lastEmitted)) {
-                emitTransformTo(out, accumulated);
-            }
-        }
-
-        public void emitTransformTo(CommandBuffer out, Matrix4f target) {
-            if (target.equals(lastEmitted)) {
-                return;
-            }
-
-            if (DisplayListManager.isIdentity(lastEmitted)) {
-                out.writeMultMatrix(target);
-            } else {
-                delta.set(lastEmitted).invert().mul(target);
-                out.writeMultMatrix(delta);
-            }
-            lastEmitted.set(target);
+            default -> GLStateManager.LOGGER.warn("[CommandBufferProcessor] Unknown opcode in buffer copy: {}", opcode);
         }
     }
 }

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

@@ -9,7 +9,7 @@ import java.nio.IntBuffer;
 /**
  * Records GL commands to a CommandBuffer during display list compilation.
  */
-public class CommandRecorder {
+public final class CommandRecorder {
     private final CommandBuffer buffer;
     private int commandCount;
 
@@ -172,6 +172,11 @@ public class CommandRecorder {
         commandCount++;
     }
 
+    public void recordScissor(int x, int y, int width, int height) {
+        buffer.writeScissor(x, y, width, height);
+        commandCount++;
+    }
+
     public void recordPointSize(float size) {
         buffer.writePointSize(size);
         commandCount++;
@@ -287,6 +292,11 @@ public class CommandRecorder {
         commandCount++;
     }
 
+    public void recordClipPlane(int plane, double a, double b, double c, double d) {
+        buffer.writeClipPlane(plane, a, b, c, d);
+        commandCount++;
+    }
+
     public void recordStencilFunc(int func, int ref, int mask) {
         buffer.writeStencilFunc(func, ref, mask);
         commandCount++;
@@ -337,6 +347,26 @@ public class CommandRecorder {
         commandCount++;
     }
 
+    public void recordDrawArrays(int mode, int start, int count) {
+        buffer.writeDrawArrays(mode, start, count);
+        commandCount++;
+    }
+
+    public void recordDrawElements(int mode, int indices_count, int type, long indices_buffer_offset) {
+        buffer.writeDrawElements(mode, indices_count, type, indices_buffer_offset);
+        commandCount++;
+    }
+
+    public void recordBindVBO(int vbo) {
+        buffer.writeBindVBO(vbo);
+        commandCount++;
+    }
+
+    public void recordBindVAO(int vao) {
+        buffer.writeBindVAO(vao);
+        commandCount++;
+    }
+
     public void recordComplexCommand(DisplayListCommand cmd) {
         buffer.writeComplexRef(cmd);
         commandCount++;

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

@@ -1,6 +1,6 @@
 package com.gtnewhorizons.angelica.glsm.recording;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.vbo.VertexBuffer;
+import com.gtnewhorizons.angelica.glsm.DisplayListManager;
 import com.gtnewhorizons.angelica.glsm.recording.commands.DisplayListCommand;
 import it.unimi.dsi.fastutil.ints.Int2IntMap;
 import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
@@ -30,9 +30,9 @@ public final class CompiledDisplayList {
 
     private final ByteBuffer commandBuffer;     // Off-heap command storage, must be freed
     private final Object[] complexObjects;      // Complex commands (TexImage2D, etc.)
-    private final VertexBuffer[] ownedVbos;     // GPU resources referenced by index
+    private final DisplayListVBO ownedVbos;     // GPU resources referenced by index
 
-    public CompiledDisplayList(ByteBuffer commandBuffer, Object[] complexObjects, VertexBuffer[] ownedVbos) {
+    public CompiledDisplayList(ByteBuffer commandBuffer, Object[] complexObjects, DisplayListVBO ownedVbos) {
         this.commandBuffer = commandBuffer;
         this.complexObjects = complexObjects;
         this.ownedVbos = ownedVbos;
@@ -62,11 +62,7 @@ public final class CompiledDisplayList {
 
         // Close VBOs
         if (ownedVbos != null) {
-            for (VertexBuffer vbo : ownedVbos) {
-                if (vbo != null) {
-                    vbo.close();
-                }
-            }
+            ownedVbos.delete();
         }
 
         // Free the command buffer (off-heap memory)
@@ -89,10 +85,7 @@ public final class CompiledDisplayList {
         return complexObjects;
     }
 
-    /**
-     * Get owned VBOs for inlining into another display list.
-     */
-    public VertexBuffer[] getOwnedVbos() {
+    public DisplayListVBO getOwnedVbos() {
         return ownedVbos;
     }
 
@@ -112,7 +105,7 @@ public final class CompiledDisplayList {
         while (ptr < end) {
             final int cmd = memGetInt(ptr);
             counts.mergeInt(cmd, 1, Integer::sum);
-            ptr += getCommandSize(cmd, ptr);
+            ptr += GLCommand.getCommandSize(cmd, ptr);
         }
         return counts;
     }
@@ -131,74 +124,13 @@ public final class CompiledDisplayList {
         while (ptr < end) {
             final int cmd = memGetInt(ptr);
             opcodes.add(cmd);
-            ptr += getCommandSize(cmd, ptr);
+            ptr += GLCommand.getCommandSize(cmd, ptr);
         }
         return opcodes;
     }
 
-    /**
-     * Get size of a command in bytes (including the opcode).
-     */
-    private static int getCommandSize(int cmd, long ptr) {
-        return switch (cmd) {
-            // Opcode-only commands (4 bytes)
-            case GLCommand.LOAD_IDENTITY, GLCommand.PUSH_MATRIX, GLCommand.POP_MATRIX -> 4;
-
-            // Single int commands (8 bytes)
-            case GLCommand.ENABLE, GLCommand.DISABLE, GLCommand.CLEAR, GLCommand.CLEAR_STENCIL,
-                 GLCommand.CULL_FACE, GLCommand.DEPTH_FUNC, GLCommand.SHADE_MODEL, GLCommand.LOGIC_OP,
-                 GLCommand.MATRIX_MODE, GLCommand.ACTIVE_TEXTURE, GLCommand.USE_PROGRAM,
-                 GLCommand.PUSH_ATTRIB, GLCommand.POP_ATTRIB, GLCommand.STENCIL_MASK,
-                 GLCommand.DEPTH_MASK, GLCommand.FRONT_FACE, GLCommand.POINT_SIZE, GLCommand.LINE_WIDTH,
-                 GLCommand.CALL_LIST, GLCommand.COMPLEX_REF -> 8;
-
-            // Two int commands (12 bytes)
-            case GLCommand.BIND_TEXTURE, GLCommand.POLYGON_MODE, GLCommand.COLOR_MATERIAL,
-                 GLCommand.LINE_STIPPLE, GLCommand.STENCIL_MASK_SEPARATE, GLCommand.FOGI,
-                 GLCommand.HINT, GLCommand.POLYGON_OFFSET, GLCommand.ALPHA_FUNC, GLCommand.FOGF,
-                 GLCommand.LIGHT_MODELF, GLCommand.LIGHT_MODELI -> 12;
-
-            // Three int commands (16 bytes)
-            case GLCommand.STENCIL_FUNC, GLCommand.STENCIL_OP, GLCommand.TEX_PARAMETERI,
-                 GLCommand.LIGHTF, GLCommand.LIGHTI,
-                 GLCommand.MATERIALF, GLCommand.TEX_PARAMETERF -> 16;
-
-            // Four int commands (20 bytes)
-            case GLCommand.VIEWPORT, GLCommand.BLEND_FUNC, GLCommand.COLOR_MASK,
-                 GLCommand.STENCIL_FUNC_SEPARATE, GLCommand.STENCIL_OP_SEPARATE,
-                 GLCommand.COLOR, GLCommand.CLEAR_COLOR, GLCommand.BLEND_COLOR,
-                 GLCommand.DRAW_RANGE -> 20;
-
-            // DRAW_RANGE_RESTORE: 56 bytes
-            // [cmd:4][vboIndex:4][start:4][count:4][flags:4][color:16f][normal:12f][texcoord:8f]
-            case GLCommand.DRAW_RANGE_RESTORE -> 56;
-
-            // DRAW_BUFFER: 8 bytes [cmd:4][mode:4]
-            case GLCommand.DRAW_BUFFER -> 8;
-
-            // DRAW_BUFFERS: 40 bytes [cmd:4][count:4][bufs:4*8]
-            case GLCommand.DRAW_BUFFERS -> 40;
-
-            // Double commands
-            case GLCommand.TRANSLATE, GLCommand.SCALE -> 28;  // cmd + 3 doubles
-            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
-
-            // Buffer commands (variable, read count)
-            case GLCommand.FOG, GLCommand.LIGHT_MODEL -> {
-                final int count = memGetInt(ptr + 8);  // pname at +4, count at +8
-                yield 12 + count * 4;
-            }
-            case GLCommand.LIGHT, GLCommand.MATERIAL -> {
-                final int count = memGetInt(ptr + 12);  // light/face at +4, pname at +8, count at +12
-                yield 16 + count * 4;
-            }
-
-            default -> throw new IllegalStateException("Unknown command: " + cmd);
-        };
+    @Override
+    public String toString() {
+        return DisplayListManager.getCompiledDisplayListString(0, this, null);
     }
 }

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

@@ -0,0 +1,58 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vao.IVertexArrayObject;
+
+/**
+ * A class that stores multiple vertex formats & their corresponding buffers.
+ */
+public final class DisplayListVBO {
+
+    private final SubVBO[] vbos;
+
+    DisplayListVBO(SubVBO[] vbos) {
+        this.vbos = vbos;
+    }
+
+    public void delete() {
+        for (SubVBO vbo : vbos) {
+            vbo.delete();
+        }
+    }
+
+    public SubVBO[] getVBOs() {
+        return vbos;
+    }
+
+    public void render(int index) {
+        vbos[index].render();
+    }
+
+    public static final class SubVBO {
+
+        private final IVertexArrayObject vao;
+        private final int drawMode;
+        private final int start;
+        private final int count;
+
+        public SubVBO(IVertexArrayObject vao, int drawMode, int start, int count) {
+            this.vao = vao;
+            this.drawMode = drawMode;
+            this.start = start;
+            this.count = count;
+        }
+
+        public void delete() {
+            vao.delete();
+        }
+
+        public void render() {
+            vao.bind();
+            vao.draw(drawMode, start, count);
+            vao.unbind();
+        }
+
+        public IVertexArrayObject getVAO() {
+            return vao;
+        }
+    }
+}

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

@@ -0,0 +1,131 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vao.IVertexArrayObject;
+import com.gtnewhorizon.gtnhlib.client.renderer.vao.IndexBuffer;
+import com.gtnewhorizon.gtnhlib.client.renderer.vao.IndexedVAO;
+import com.gtnewhorizon.gtnhlib.client.renderer.vao.VAOManager;
+import com.gtnewhorizon.gtnhlib.client.renderer.vbo.IVertexBuffer;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.DefaultVertexFormat;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormat;
+import org.lwjgl.opengl.GL11;
+
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAddress0;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAlloc;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memCopy;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memFree;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.nmemFree;
+
+/**
+ * Compiles multiple ByteBuffers of the same Vertex format into a VBO. Any buffer added to the builder will be freed afterward.
+ */
+public final class DisplayListVBOBuilder {
+
+    // Removes the need for a HashMap. Since it's only an array of 16 values, this should be faster
+    private final List<FormatData>[] formats = new List[VertexFlags.BITSET_SIZE];
+    private int count;
+
+    public DisplayListVBOBuilder addDraw(VertexFormat format, int drawMode, List<ByteBuffer> buffers) {
+        List<FormatData> data = formats[format.getVertexFlags()];
+        if (data == null) {
+            data = new ArrayList<>();
+            formats[format.getVertexFlags()] = data;
+        }
+        data.add(new FormatData(buffers, drawMode, count));
+        count++;
+        return this;
+    }
+
+    public DisplayListVBOBuilder addDraws(List<AccumulatedDraw> draws) {
+        for (AccumulatedDraw draw : draws) {
+            addDraw(draw.format, draw.drawMode, draw.drawBuffers);
+        }
+        return this;
+    }
+
+    public DisplayListVBO build() {
+        final DisplayListVBO.SubVBO[] vbos = new DisplayListVBO.SubVBO[count];
+        final ArrayList<ByteBuffer> allBuffers = new ArrayList<>();
+        for (int i = 0; i < VertexFlags.BITSET_SIZE; i++) {
+            List<FormatData> formatData = formats[i];
+            if (formatData == null) continue;
+            final VertexFormat format = DefaultVertexFormat.ALL_FORMATS[i];
+            int start = 0;
+            final IVertexArrayObject vao = VAOManager.createStorageVAO(format, -1, 0); // drawMode will be ignored
+            final IVertexBuffer vbo = vao.getVBO();
+            for (FormatData data : formatData) {
+                int vertexCount;
+                final List<ByteBuffer> drawBuffers = data.buffers;
+                if (drawBuffers.size() == 1) {
+                    final ByteBuffer buffer = drawBuffers.get(0);
+                    allBuffers.add(buffer);
+                    vertexCount = format.getVertexCount(buffer);
+                } else {
+                    allBuffers.addAll(drawBuffers);
+                    int size = 0;
+                    for (ByteBuffer buffer : drawBuffers) {
+                        size += buffer.remaining();
+                    }
+                    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 {
+                    vbos[data.drawIndex] = new DisplayListVBO.SubVBO(vao, data.drawMode, start, vertexCount);
+                }
+
+
+                start += vertexCount;
+            }
+            ByteBuffer bigBuffer = mergeAndDelete(allBuffers);
+            vbo.allocate(bigBuffer, start);
+            memFree(bigBuffer);
+
+            allBuffers.clear();
+        }
+        return new DisplayListVBO(vbos);
+    }
+
+    private static ByteBuffer mergeAndDelete(List<ByteBuffer> buffers) {
+        if (buffers.size() == 1) {
+            return buffers.get(0);
+        }
+        int needed = 0;
+        for (ByteBuffer buffer : buffers) {
+            needed += buffer.remaining();
+        }
+
+        ByteBuffer out = memAlloc(needed);
+        long dst = memAddress0(out);
+
+        for (ByteBuffer buffer : buffers) {
+            final int len = buffer.limit();
+            final long address = memAddress0(buffer);
+            memCopy(address, dst, len);
+            dst += len;
+
+            nmemFree(address);
+        }
+
+        out.limit(needed);
+        return out;
+    }
+
+    private static final class FormatData {
+
+        private final List<ByteBuffer> buffers;
+        private final int drawMode;
+        private final int drawIndex;
+
+        public FormatData(List<ByteBuffer> buffers, int drawMode, int drawIndex) {
+            this.buffers = buffers;
+            this.drawMode = drawMode;
+            this.drawIndex = drawIndex;
+        }
+    }
+}

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

@@ -1,5 +1,7 @@
 package com.gtnewhorizons.angelica.glsm.recording;
 
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memGetInt;
+
 /**
  * Command opcodes for ByteBuffer-based display list serialization.
  * Each command has a fixed layout described in comments.
@@ -49,6 +51,7 @@ public final class GLCommand {
     public static final int COLOR_MASK = 42;         // [cmd:4][r:4][g:4][b:4][a:4] (0 or 1 each)
     public static final int STENCIL_FUNC_SEPARATE = 43; // [cmd:4][face:4][func:4][ref:4][mask:4]
     public static final int STENCIL_OP_SEPARATE = 44; // [cmd:4][face:4][sfail:4][dpfail:4][dppass:4]
+    public static final int SCISSOR = 45;             // [cmd:4][x:4][y:4][width:4][height:4]
 
     // === Float commands ===
     public static final int POINT_SIZE = 50;         // [cmd:4][size:4f]
@@ -86,18 +89,27 @@ public final class GLCommand {
     public static final int LIGHT = 91;              // [cmd:4][light:4][pname:4][count:4][params:16f] = 32 bytes
     public static final int LIGHT_MODEL = 92;        // [cmd:4][pname:4][count:4][params:16f] = 28 bytes
     public static final int MATERIAL = 93;           // [cmd:4][face:4][pname:4][count:4][params:16f] = 32 bytes
+    public static final int CLIP_PLANE = 94;         // [cmd:4][plane:4][a:8d][b:8d][c:8d][d:8d] = 40 bytes
 
     // === Draw commands ===
-    public static final int DRAW_RANGE = 100;        // [cmd:4][vboIndex:4][start:4][count:4][hasBrightness:4] = 20 bytes
-    public static final int CALL_LIST = 101;         // [cmd:4][listId:4] = 8 bytes
-    public static final int DRAW_BUFFER = 102;       // [cmd:4][mode:4] = 8 bytes
-    public static final int DRAW_BUFFERS = 103;      // [cmd:4][count:4][bufs:4*8] = 40 bytes (up to 8 buffers)
+    public static final int DRAW_RANGE = 100;        // [cmd:4][vboIndex:4] = 8 bytes
+    public static final int DRAW_RANGE_RESTORE = 101; // [cmd:4][vboIndex:4][flags:4][color:4][normal:4][lastTexCoord:8f] = 28 bytes
+    public static final int CALL_LIST = 102;         // [cmd:4][listId:4] = 8 bytes
+
+
+    public static final int DRAW_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)
     /**
      * Draw VBO range with attribute restoration after draw.
      * Used for immediate mode VBOs to restore GL current state (color, normal, texcoord).
      */
-    public static final int DRAW_RANGE_RESTORE = 104; // [cmd:4][vboIndex:4][start:4][count:4][flags:4]
-                                                      // [lastColor:16f][lastNormal:12f][lastTexCoord:8f] = 56 bytes
+
+
+    // === Bind commands ===
+    public static final int BIND_VBO = 120;
+    public static final int BIND_VAO = 121;
 
     // === Complex object reference ===
     public static final int COMPLEX_REF = 255;       // [cmd:4][index:4] = 8 bytes
@@ -137,6 +149,7 @@ public final class GLCommand {
             case STENCIL_OP -> "STENCIL_OP";
             case TEX_PARAMETERI -> "TEX_PARAMETERI";
             case VIEWPORT -> "VIEWPORT";
+            case SCISSOR -> "SCISSOR";
             case BLEND_FUNC -> "BLEND_FUNC";
             case COLOR_MASK -> "COLOR_MASK";
             case STENCIL_FUNC_SEPARATE -> "STENCIL_FUNC_SEPARATE";
@@ -167,13 +180,85 @@ public final class GLCommand {
             case LIGHT -> "LIGHT";
             case LIGHT_MODEL -> "LIGHT_MODEL";
             case MATERIAL -> "MATERIAL";
+            case CLIP_PLANE -> "CLIP_PLANE";
             case DRAW_RANGE -> "DRAW_RANGE";
             case CALL_LIST -> "CALL_LIST";
             case DRAW_BUFFER -> "DRAW_BUFFER";
             case DRAW_BUFFERS -> "DRAW_BUFFERS";
-            case DRAW_RANGE_RESTORE -> "DRAW_RANGE_RESTORE";
             case COMPLEX_REF -> "COMPLEX_REF";
+            case DRAW_RANGE_RESTORE -> "DRAW_RANGE_RESTORE";
+            case BIND_VAO -> "BIND_VAO";
+            case BIND_VBO -> "BIND_VBO";
             default -> "UNKNOWN(" + opcode + ")";
         };
     }
+
+    /**
+     * Get size of a command in bytes (including the opcode).
+     */
+    public static int getCommandSize(int cmd, long ptr) {
+        return switch (cmd) {
+            // Opcode-only commands (4 bytes)
+            case GLCommand.LOAD_IDENTITY, GLCommand.PUSH_MATRIX, GLCommand.POP_MATRIX -> 4;
+
+            // Single int commands (8 bytes)
+            case GLCommand.ENABLE, GLCommand.DISABLE, GLCommand.CLEAR, GLCommand.CLEAR_STENCIL,
+                 GLCommand.CULL_FACE, GLCommand.DEPTH_FUNC, GLCommand.SHADE_MODEL, GLCommand.LOGIC_OP,
+                 GLCommand.MATRIX_MODE, GLCommand.ACTIVE_TEXTURE, GLCommand.USE_PROGRAM,
+                 GLCommand.PUSH_ATTRIB, GLCommand.POP_ATTRIB, GLCommand.STENCIL_MASK,
+                 GLCommand.DEPTH_MASK, GLCommand.FRONT_FACE, GLCommand.POINT_SIZE, GLCommand.LINE_WIDTH,
+                 GLCommand.CALL_LIST, GLCommand.COMPLEX_REF, GLCommand.DRAW_RANGE, GLCommand.BIND_VBO,
+                 GLCommand.BIND_VAO -> 8;
+
+            // Two int commands (12 bytes)
+            case GLCommand.BIND_TEXTURE, GLCommand.POLYGON_MODE, GLCommand.COLOR_MATERIAL,
+                 GLCommand.LINE_STIPPLE, GLCommand.STENCIL_MASK_SEPARATE, GLCommand.FOGI,
+                 GLCommand.HINT, GLCommand.POLYGON_OFFSET, GLCommand.ALPHA_FUNC, GLCommand.FOGF,
+                 GLCommand.LIGHT_MODELF, GLCommand.LIGHT_MODELI -> 12;
+
+            // Three int commands (16 bytes)
+            case GLCommand.STENCIL_FUNC, GLCommand.STENCIL_OP, GLCommand.TEX_PARAMETERI,
+                 GLCommand.LIGHTF, GLCommand.LIGHTI,
+                 GLCommand.MATERIALF, GLCommand.TEX_PARAMETERF, GLCommand.DRAW_ARRAYS -> 16;
+
+            // Four int commands (20 bytes)
+            case GLCommand.VIEWPORT, GLCommand.BLEND_FUNC, GLCommand.COLOR_MASK,
+                 GLCommand.STENCIL_FUNC_SEPARATE, GLCommand.STENCIL_OP_SEPARATE,
+                 GLCommand.SCISSOR,
+                 GLCommand.COLOR, GLCommand.CLEAR_COLOR, GLCommand.BLEND_COLOR -> 20;
+
+            case GLCommand.DRAW_ELEMENTS -> 24;
+
+            // DRAW_RANGE_RESTORE: 28 bytes
+            case GLCommand.DRAW_RANGE_RESTORE -> 28;
+
+            // DRAW_BUFFER: 8 bytes [cmd:4][mode:4]
+            case GLCommand.DRAW_BUFFER -> 8;
+
+            // DRAW_BUFFERS: 40 bytes [cmd:4][count:4][bufs:4*8]
+            case GLCommand.DRAW_BUFFERS -> 40;
+
+            // Double commands
+            case GLCommand.TRANSLATE, GLCommand.SCALE -> 28;  // cmd + 3 doubles
+            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
+
+            // Buffer commands (variable, read count)
+            case GLCommand.FOG, GLCommand.LIGHT_MODEL -> {
+                final int count = memGetInt(ptr + 8);  // pname at +4, count at +8
+                yield 12 + count * 4;
+            }
+            case GLCommand.LIGHT, GLCommand.MATERIAL -> {
+                final int count = memGetInt(ptr + 12);  // light/face at +4, pname at +8, count at +12
+                yield 16 + count * 4;
+            }
+            case GLCommand.CLIP_PLANE -> 40;  // cmd + plane + 4 doubles
+
+            default -> throw new IllegalStateException("Unknown command: " + cmd);
+        };
+    }
 }

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

@@ -0,0 +1,449 @@
+package com.gtnewhorizons.angelica.glsm.recording;
+
+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.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * Records immediate mode GL calls (glBegin/glEnd/glVertex) via {@link DirectTessellator}.
+ * Used both during display list compilation and for live immediate mode emulation in core profile.
+ */
+public final class ImmediateModeRecorder {
+    private static final DirectTessellator tessellator = new DirectTessellator(TessellatorManager.DEFAULT_BUFFER_SIZE);
+
+    /** Separate tessellator for the splash thread. Nulled after splash completes. */
+    private static DirectTessellator splashTessellator;
+
+    private ImmediateModeRecorder() {
+
+    }
+
+    public static void initSplashTessellator() {
+        splashTessellator = new DirectTessellator(TessellatorManager.DEFAULT_BUFFER_SIZE);
+    }
+
+    public static void destroySplashTessellator() {
+        splashTessellator = null;
+    }
+
+    private static DirectTessellator tessellator() {
+        final DirectTessellator splash = splashTessellator;
+        if (splash != null && Thread.currentThread() != GLStateManager.getMainThread()) {
+            return splash;
+        }
+        return tessellator;
+    }
+
+    public static DirectTessellator getInternalTessellator() {
+        return tessellator();
+    }
+
+    public static boolean isDrawing() {
+        return tessellator().isDrawing;
+    }
+
+    /**
+     * Set the current texture coordinate.
+     * Called by GLStateManager.glTexCoord*.
+     */
+    public static void setTexCoord(float s, float t) {
+        tessellator().setTextureUV(s, t);
+    }
+
+    /**
+     * Set the current lightmap coordinate as packed brightness.
+     * Called by GLStateManager.glMultiTexCoord2f for unit 1 during recording/drawing.
+     */
+    public static void setLightmapCoord(float s, float t) {
+        tessellator().setBrightness(((int) t << 16) | ((int) s & 0xFFFF));
+    }
+
+    /**
+     * Set the current normal vector.
+     * Called by GLStateManager.glNormal*.
+     */
+    public static void setNormal(float x, float y, float z) {
+        tessellator().setNormal(x, y, z);
+    }
+
+    /**
+     * Set the current color on the internal tessellator.
+     * Called by GLStateManager.glColor* when inside a glBegin/glEnd block.
+     */
+    public static void setColor(float r, float g, float b, float a) {
+        tessellator().setColorRGBA((int) (r * 255.0f), (int) (g * 255.0f), (int) (b * 255.0f), (int) (a * 255.0f));
+    }
+
+    /**
+     * Start recording a new primitive.
+     * Resets the tessellator to clear any data from the previous draw.
+     *
+     * @param primitiveType GL primitive type (GL_QUADS, GL_TRIANGLES, etc.)
+     */
+    public static void begin(int primitiveType) {
+        final DirectTessellator t = tessellator();
+        t.reset();
+        t.startDrawing(primitiveType);
+    }
+
+    /**
+     * Start recording a new primitive with initial color sync from GLSM cache.
+     * Used for live immediate mode emulation only (not display list recording).
+     */
+    public static void beginLive(int primitiveType) {
+        final DirectTessellator t = tessellator();
+        t.reset();
+        t.startDrawing(primitiveType);
+        final var c = GLStateManager.getColor();
+        t.setColorRGBA((int) (c.getRed() * 255.0f), (int) (c.getGreen() * 255.0f), (int) (c.getBlue() * 255.0f), (int) (c.getAlpha() * 255.0f));
+    }
+
+    /**
+     * End the current primitive, convert to quads/lines, and return them immediately.
+     * This allows the caller to create AccumulatedDraw at the correct command position.
+     *
+     * @return Result containing quads, lines, and flags, or null if no geometry was produced
+     */
+    public static DirectTessellator end() {
+        final DirectTessellator t = tessellator();
+        if (!t.isDrawing) {
+            throw new IllegalStateException("glEnd called without glBegin");
+        }
+
+        t.isDrawing = false;
+
+        if (t.isEmpty()) return null;
+
+        return t;
+    }
+
+    /**
+     * Record a vertex with current attributes.
+     * Color is read from GLStateManager at call time.
+     */
+    public static void vertex(float x, float y, float z) {
+        final DirectTessellator t = tessellator();
+        if (!t.isDrawing) {
+            throw new IllegalStateException("glVertex called outside glBegin/glEnd");
+        }
+        t.addVertex(x, y, z);
+    }
+
+    /**
+     * Check if any immediate mode geometry has been captured.
+     *
+     * <p>Note: With immediate flush mode, this will typically return false as geometry
+     * is returned from end() immediately. This method is kept for edge cases
+     * where primitives might fail to convert (e.g., incomplete quads).
+     */
+    public static boolean hasGeometry() {
+        return tessellator().vertexCount != 0;
+    }
+
+    /**
+     * Reset all state including current texcoord/normal.
+     * Called when starting a new display list.
+     */
+    public static void reset() {
+        tessellator().reset();
+    }
+
+    private static final int LOC_POSITION = Usage.POSITION.getAttributeLocation();
+    private static final int LOC_COLOR = Usage.COLOR.getAttributeLocation();
+    private static final int LOC_UV0 = Usage.PRIMARY_UV.getAttributeLocation();
+    private static final int LOC_UV1 = Usage.SECONDARY_UV.getAttributeLocation();
+    private static final int LOC_NORMAL = Usage.NORMAL.getAttributeLocation();
+    private static final int NUM_ATTRIBS = 1 + Arrays.stream(Usage.values())
+        .mapToInt(Usage::getAttributeLocation)
+            .max().orElse(0);
+
+    private static final 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;
+    }
+
+    private static final AttribReader[] readers = new AttribReader[NUM_ATTRIBS];
+    private static int nonPositionCount;
+    private static final int[] nonPositionIndices = new int[NUM_ATTRIBS - 1];
+    private static int positionReaderIndex = -1;
+
+    static {
+        for (int i = 0; i < NUM_ATTRIBS; i++) {
+            readers[i] = new AttribReader();
+        }
+    }
+
+    /**
+     * Process a glDrawArrays call during display list recording.
+     * Reads vertex data from VBOs or client memory referenced by VertexAttribState and converts to immediate mode geometry.
+     */
+    public static DirectTessellator processDrawArraysFromAttribs(int mode, int first, int count) {
+        final int readVBOCount = readbackAttribVBOs(first, count);
+
+        try {
+            prepareReaders();
+            if (positionReaderIndex < 0) return null;
+            return readVerticesFromBuffer(mode, first, count);
+        } finally {
+            freeReadbackBuffers(readVBOCount);
+        }
+    }
+
+    /**
+     * 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 = RENDER_BACKEND.getBufferParameteri(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) {
+                GLStateManager.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);
+            RENDER_BACKEND.getBufferSubData(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 = RENDER_BACKEND.getBufferParameteri(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 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);
+                    RENDER_BACKEND.getBufferSubData(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() {
+        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 AttribReader r = readers[i];
+            r.data = buf;
+            r.stride = a.effectiveStride();
+            r.baseOffset = (int) (a.offset - scratchAttribBaseOffsets[i]);
+            r.size = a.size;
+            r.loc = i;
+            r.attrib = a;
+
+            if (i == LOC_POSITION) {
+                positionReaderIndex = i;
+            } else {
+                nonPositionIndices[nonPositionCount++] = i;
+            }
+        }
+    }
+
+    private static DirectTessellator readVerticesFromBuffer(int mode, int first, int count) {
+        begin(mode);
+        final DirectTessellator t = tessellator();
+
+        for (int i = first; i < first + count; i++) {
+            readVertexFromBuffer(t, i);
+        }
+
+        return end();
+    }
+
+    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;
+            case GL11.GL_UNSIGNED_SHORT -> ebo.getShort(eboOffset + i * 2) & 0xFFFF;
+            case GL11.GL_UNSIGNED_INT -> ebo.getInt(eboOffset + i * 4);
+            default -> i;
+        };
+    }
+
+    private static void readVertexFromBuffer(DirectTessellator t, int vertexIndex) {
+        for (int i = 0; i < nonPositionCount; i++) {
+            final AttribReader r = readers[nonPositionIndices[i]];
+            final int base = r.baseOffset + vertexIndex * r.stride;
+            emitAttrib(t, r, base);
+        }
+
+        if (positionReaderIndex >= 0) {
+            final AttribReader r = readers[positionReaderIndex];
+            final int base = r.baseOffset + vertexIndex * r.stride;
+            t.addVertex(
+                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);
+        }
+    }
+
+    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));
+        } 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);
+        } else if (r.loc == LOC_UV1) {
+            if (r.attrib.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) {
+                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;
+            t.setColorRGBA((int) (cr * 255.0f), (int) (cg * 255.0f), (int) (cb * 255.0f), (int) (ca * 255.0f));
+        }
+    }
+
+}

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

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

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

@@ -1,11 +1,9 @@
 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;
 import org.lwjgl.BufferUtils;
-import org.lwjgl.opengl.GL11;
 
 import java.nio.FloatBuffer;
 
@@ -13,7 +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/TexImage2DCmd.java

@@ -1,6 +1,5 @@
 package com.gtnewhorizons.angelica.glsm.recording.commands;
 
-import com.github.bsideup.jabel.Desugar;
 import com.gtnewhorizons.angelica.glsm.GLDebug;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import org.jetbrains.annotations.NotNull;
@@ -16,7 +15,6 @@ import java.nio.IntBuffer;
  * Command: glTexImage2D(target, level, internalformat, width, height, border, format, type, pixels)
  * Specifies a two-dimensional texture image during display list playback.
  */
-@Desugar
 public record TexImage2DCmd(
     int target,
     int level,

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

@@ -1,6 +1,5 @@
 package com.gtnewhorizons.angelica.glsm.recording.commands;
 
-import com.github.bsideup.jabel.Desugar;
 import com.gtnewhorizons.angelica.glsm.GLDebug;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import org.jetbrains.annotations.NotNull;
@@ -16,7 +15,6 @@ import java.nio.IntBuffer;
  * 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.
  */
-@Desugar
 public record TexSubImage2DCmd(
     int target,
     int level,

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

@@ -0,0 +1,619 @@
+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.Opcodes;
+import org.objectweb.asm.tree.AbstractInsnNode;
+import org.objectweb.asm.tree.ClassNode;
+import org.objectweb.asm.tree.IntInsnNode;
+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.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";
+
+    // 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()
+            .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("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("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("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("glBindFramebuffer")
+            .add("glDeleteFramebuffers")
+            .add("glGenFramebuffers")
+            .add("glCheckFramebufferStatus")
+            .add("glFramebufferTexture2D")
+            .add("glVertexAttribIPointer")
+            .add("glGenerateMipmap")
+            .add("glGetFramebufferAttachmentParameteri")
+            .add("glBlitFramebuffer");
+        final var gl31 = RedirectMap.newMap()
+            .add("glDrawElementsInstanced");
+        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")
+        );
+
+        // 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();
+    }
+
+    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 : 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);
+                        if (redirects != null) {
+                            final String glsmName = redirects.get(mNode.name);
+                            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;
+                        }
+                    }
+                }
+            }
+            if (ASSERT_MAIN_THREAD && redirectInMethod && !transformedName.startsWith(SplashProgress) && !(transformedName.startsWith(MinecraftClient) && ExcludedMinecraftMainThreadChecks.contains(mn.name))) {
+                mn.instructions.insert(new MethodInsnNode(Opcodes.INVOKESTATIC, GLStateManager, "assertMainThread", "()V", false));
+            }
+        }
+
+        return changed;
+    }
+
+    private static final class RedirectMap<K> extends HashMap<K, K> {
+
+        public static RedirectMap<String> newMap() {
+            return new RedirectMap<>();
+        }
+
+        public RedirectMap<K> add(K name) {
+            this.put(name, name);
+            return this;
+        }
+
+        public RedirectMap<K> add(K name, K newName) {
+            this.put(name, newName);
+            return this;
+        }
+    }
+}

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

@@ -22,8 +22,7 @@ public class BooleanStateStack extends BooleanState implements IStateStack<Boole
     protected int savedDepth;
 
     public BooleanStateStack(int glCap) {
-        // Most booleans default to false
-        this(glCap, false);
+        this(glCap, false, false);
     }
 
     /**
@@ -34,7 +33,18 @@ public class BooleanStateStack extends BooleanState implements IStateStack<Boole
      * @param initialState initial enabled state
      */
     public BooleanStateStack(int glCap, boolean initialState) {
-        super(glCap);
+        this(glCap, initialState, false);
+    }
+
+    /**
+     * Create a BooleanStateStack with custom initial state and FFP flag.
+     *
+     * @param glCap GL capability constant
+     * @param initialState initial enabled state
+     * @param ffpStateOnly when true, GL calls are skipped when FFP emulation is active
+     */
+    public BooleanStateStack(int glCap, boolean initialState, boolean ffpStateOnly) {
+        super(glCap, ffpStateOnly);
         this.enabled = initialState;
         stack = new boolean[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
     }

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

@@ -1,7 +1,7 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
-import org.lwjgl.opengl.GL11;
+import com.gtnewhorizons.angelica.glsm.backend.BackendManager;
 import org.lwjgl.opengl.GL13;
 
 /**
@@ -12,12 +12,12 @@ public class TextureUnitBooleanStateStack extends BooleanStateStack {
     private final int unitIndex;
 
     public TextureUnitBooleanStateStack(int glCap, int unitIndex) {
-        super(glCap);
+        super(glCap, false, true); // All texture enable/disable states are FFP-only
         this.unitIndex = unitIndex;
     }
 
     public TextureUnitBooleanStateStack(int glCap, int unitIndex, boolean initialState) {
-        super(glCap, initialState);
+        super(glCap, initialState, true);
         this.unitIndex = unitIndex;
     }
 
@@ -41,12 +41,14 @@ public class TextureUnitBooleanStateStack extends BooleanStateStack {
         if (bypass || enabled != this.enabled) {
             if (!bypass) this.enabled = enabled;
 
-            int currentUnit = GLStateManager.getActiveTextureUnit();
-            boolean needsSwitch = currentUnit != unitIndex;
+            if (!ffpStateOnly) {
+                final int currentUnit = GLStateManager.getActiveTextureUnit();
+                final boolean needsSwitch = currentUnit != unitIndex;
 
-            if (needsSwitch) GL13.glActiveTexture(GL13.GL_TEXTURE0 + unitIndex);
-            if (enabled) GL11.glEnable(glCap); else GL11.glDisable(glCap);
-            if (needsSwitch) GL13.glActiveTexture(GL13.GL_TEXTURE0 + currentUnit);
+                if (needsSwitch) BackendManager.RENDER_BACKEND.activeTexture(GL13.GL_TEXTURE0 + unitIndex);
+                if (enabled) BackendManager.RENDER_BACKEND.enable(glCap); else BackendManager.RENDER_BACKEND.disable(glCap);
+                if (needsSwitch) BackendManager.RENDER_BACKEND.activeTexture(GL13.GL_TEXTURE0 + currentUnit);
+            }
         }
     }
 

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/Vec3fStack.java

@@ -0,0 +1,47 @@
+package com.gtnewhorizons.angelica.glsm.stacks;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.joml.Vector3f;
+
+/**
+ * Stack for a Vector3f value (e.g. current normal).
+ */
+public class Vec3fStack implements IStateStack<Vec3fStack> {
+
+    private final Vector3f value;
+    private final float[][] stack;
+    private int pointer;
+
+    public Vec3fStack(Vector3f value) {
+        this.value = value;
+        stack = new float[GLStateManager.MAX_ATTRIB_STACK_DEPTH][3];
+    }
+
+    @Override
+    public Vec3fStack push() {
+        if (pointer == stack.length) {
+            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
+        }
+        stack[pointer][0] = value.x;
+        stack[pointer][1] = value.y;
+        stack[pointer][2] = value.z;
+        pointer++;
+        return this;
+    }
+
+    @Override
+    public Vec3fStack pop() {
+        if (pointer == 0) {
+            throw new IllegalStateException("Stack underflow");
+        }
+        pointer--;
+        value.set(stack[pointer][0], stack[pointer][1], stack[pointer][2]);
+        return this;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return pointer == 0;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/Vec4fStack.java

@@ -0,0 +1,48 @@
+package com.gtnewhorizons.angelica.glsm.stacks;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.joml.Vector4f;
+
+/**
+ * Stack for a Vector4f value (e.g. current texture coordinates).
+ */
+public class Vec4fStack implements IStateStack<Vec4fStack> {
+
+    private final Vector4f value;
+    private final float[][] stack;
+    private int pointer;
+
+    public Vec4fStack(Vector4f value) {
+        this.value = value;
+        stack = new float[GLStateManager.MAX_ATTRIB_STACK_DEPTH][4];
+    }
+
+    @Override
+    public Vec4fStack push() {
+        if (pointer == stack.length) {
+            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
+        }
+        stack[pointer][0] = value.x;
+        stack[pointer][1] = value.y;
+        stack[pointer][2] = value.z;
+        stack[pointer][3] = value.w;
+        pointer++;
+        return this;
+    }
+
+    @Override
+    public Vec4fStack pop() {
+        if (pointer == 0) {
+            throw new IllegalStateException("Stack underflow");
+        }
+        pointer--;
+        value.set(stack[pointer][0], stack[pointer][1], stack[pointer][2], stack[pointer][3]);
+        return this;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return pointer == 0;
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/states/AlphaState.java

@@ -7,7 +7,7 @@ import org.lwjgl.opengl.GL11;
 @Getter
 public class AlphaState implements ISettableState<AlphaState> {
     @Setter protected int function = GL11.GL_ALWAYS;
-    @Setter protected float reference = -1.0F;
+    @Setter protected float reference = 0.0F;
 
     @Override
     public AlphaState set(AlphaState state) {

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/states/BlendState.java

@@ -3,6 +3,7 @@ package com.gtnewhorizons.angelica.glsm.states;
 import lombok.Getter;
 import lombok.Setter;
 import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL14;
 
 
 @Getter @Setter
@@ -11,6 +12,12 @@ public class BlendState implements ISettableState<BlendState> {
     protected int dstRgb = GL11.GL_ZERO;
     protected int srcAlpha = GL11.GL_ONE;
     protected int dstAlpha = GL11.GL_ZERO;
+    protected int equationRgb = GL14.GL_FUNC_ADD;
+    protected int equationAlpha = GL14.GL_FUNC_ADD;
+    protected float blendColorR = 0.0f;
+    protected float blendColorG = 0.0f;
+    protected float blendColorB = 0.0f;
+    protected float blendColorA = 0.0f;
 
     public BlendState() {}
 
@@ -39,6 +46,12 @@ public class BlendState implements ISettableState<BlendState> {
         this.dstRgb = state.dstRgb;
         this.srcAlpha = state.srcAlpha;
         this.dstAlpha = state.dstAlpha;
+        this.equationRgb = state.equationRgb;
+        this.equationAlpha = state.equationAlpha;
+        this.blendColorR = state.blendColorR;
+        this.blendColorG = state.blendColorG;
+        this.blendColorB = state.blendColorB;
+        this.blendColorA = state.blendColorA;
         return this;
     }
 
@@ -46,7 +59,13 @@ public class BlendState implements ISettableState<BlendState> {
     public boolean sameAs(Object state) {
         if (this == state) return true;
         if (!(state instanceof BlendState blendState)) return false;
-        return srcRgb == blendState.srcRgb && dstRgb == blendState.dstRgb && srcAlpha == blendState.srcAlpha && dstAlpha == blendState.dstAlpha;
+        return srcRgb == blendState.srcRgb && dstRgb == blendState.dstRgb
+            && srcAlpha == blendState.srcAlpha && dstAlpha == blendState.dstAlpha
+            && equationRgb == blendState.equationRgb && equationAlpha == blendState.equationAlpha
+            && Float.compare(blendColorR, blendState.blendColorR) == 0
+            && Float.compare(blendColorG, blendState.blendColorG) == 0
+            && Float.compare(blendColorB, blendState.blendColorB) == 0
+            && Float.compare(blendColorA, blendState.blendColorA) == 0;
     }
 
     @Override

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/states/BooleanState.java

@@ -4,13 +4,26 @@ import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import lombok.Getter;
 import org.lwjgl.opengl.GL11;
 
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
 public class BooleanState implements ISettableState<BooleanState> {
     protected final int glCap;
+    protected final boolean ffpStateOnly;
 
     @Getter protected boolean enabled;
+    protected boolean stateUnknown;
 
     public BooleanState(int glCap) {
+        this(glCap, false);
+    }
+
+    public BooleanState(int glCap, boolean ffpStateOnly) {
         this.glCap = glCap;
+        this.ffpStateOnly = ffpStateOnly;
+    }
+
+    public void setUnknownState() {
+        stateUnknown = true;
     }
 
     public void disable() {
@@ -23,15 +36,17 @@ public class BooleanState implements ISettableState<BooleanState> {
 
     public void setEnabled(boolean enabled) {
         final boolean bypass = GLStateManager.shouldBypassCache();
-        if (bypass || enabled != this.enabled || (this.glCap == GL11.GL_BLEND && GLStateManager.vendorIsAMD() && GLStateManager.isPoppingAttributes())) {
+        if (stateUnknown || bypass || enabled != this.enabled || (this.glCap == GL11.GL_BLEND && GLStateManager.vendorIsAMD() && GLStateManager.isPoppingAttributes())) {
+            stateUnknown = false;
             if (!bypass) {
                 this.enabled = enabled;
             }
-            // Always call GL - the calling method controls whether we reach here based on recording mode
-            if (enabled) {
-                GL11.glEnable(this.glCap);
-            } else {
-                GL11.glDisable(this.glCap);
+            if (!ffpStateOnly) {
+                if (enabled) {
+                    RENDER_BACKEND.enable(this.glCap);
+                } else {
+                    RENDER_BACKEND.disable(this.glCap);
+                }
             }
         }
     }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/states/ClipPlaneState.java

@@ -0,0 +1,34 @@
+package com.gtnewhorizons.angelica.glsm.states;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.joml.Matrix4f;
+import org.joml.Vector4f;
+
+import java.nio.FloatBuffer;
+
+/**
+ * Stores eye-space clip plane equations for core profile emulation.
+ */
+public class ClipPlaneState {
+    private final float[][] eyePlanes = new float[GLStateManager.MAX_CLIP_PLANES][4];
+
+    private static final Vector4f tempPlane = new Vector4f();
+    private static final Matrix4f tempInverse = new Matrix4f();
+
+    public void setPlane(int index, double a, double b, double c, double d, Matrix4f modelView) {
+        final float[] dest = eyePlanes[index];
+        modelView.invert(tempInverse);
+        tempPlane.set((float) a, (float) b, (float) c, (float) d);
+        tempInverse.transformTranspose(tempPlane);
+        dest[0] = tempPlane.x;
+        dest[1] = tempPlane.y;
+        dest[2] = tempPlane.z;
+        dest[3] = tempPlane.w;
+    }
+
+    /** Writes the 4-component eye-space plane equation into {@code buf} at its current position. */
+    public void putEyePlane(int index, FloatBuffer buf) {
+        final float[] p = eyePlanes[index];
+        buf.put(p[0]).put(p[1]).put(p[2]).put(p[3]);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/states/DepthState.java

@@ -8,11 +8,13 @@ import org.lwjgl.opengl.GL11;
 public class DepthState implements ISettableState<DepthState> {
     protected boolean enabled = true;
     protected int func = GL11.GL_LESS;
+    protected double clearValue = 1.0;
 
     @Override
     public DepthState set(DepthState state) {
         this.enabled = state.enabled;
         this.func = state.func;
+        this.clearValue = state.clearValue;
         return this;
     }
 
@@ -20,7 +22,7 @@ public class DepthState implements ISettableState<DepthState> {
     public boolean sameAs(Object state) {
         if (this == state) return true;
         if (!(state instanceof DepthState depthState)) return false;
-        return enabled == depthState.enabled && func == depthState.func;
+        return enabled == depthState.enabled && func == depthState.func && Double.compare(clearValue, depthState.clearValue) == 0;
     }
     @Override
     public DepthState copy() {

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/states/FogState.java

@@ -16,6 +16,8 @@ public class FogState implements ISettableState<FogState> {
     protected float density = 1.0F;
     protected float start;
     protected float end = 1.0F;
+    /** Fog distance computation mode: 0=EYE_RADIAL, 1=EYE_PLANE, 2=EYE_PLANE_ABS */
+    protected int fogDistanceMode = 2;
 
     @Override
     public FogState set(FogState state) {
@@ -23,16 +25,20 @@ public class FogState implements ISettableState<FogState> {
         this.fogColor.set(state.fogColor);
         this.fogAlpha = state.fogAlpha;
         this.fogColorBuffer.put(0, state.fogColorBuffer.get(0));
+        this.fogColorBuffer.put(1, state.fogColorBuffer.get(1));
+        this.fogColorBuffer.put(2, state.fogColorBuffer.get(2));
+        this.fogColorBuffer.put(3, state.fogColorBuffer.get(3));
         this.density = state.density;
         this.start = state.start;
         this.end = state.end;
+        this.fogDistanceMode = state.fogDistanceMode;
         return this;
     }
     @Override
     public boolean sameAs(Object state) {
         if (this == state) return true;
         if (!(state instanceof FogState fogState)) return false;
-        return fogMode == fogState.fogMode && Float.compare(fogState.fogAlpha, fogAlpha) == 0 && Float.compare(fogState.density, density) == 0 && Float.compare(fogState.start, start) == 0 && Float.compare(fogState.end, end) == 0 && fogColor.equals(fogState.fogColor);
+        return fogMode == fogState.fogMode && fogDistanceMode == fogState.fogDistanceMode && Float.compare(fogState.fogAlpha, fogAlpha) == 0 && Float.compare(fogState.density, density) == 0 && Float.compare(fogState.start, start) == 0 && Float.compare(fogState.end, end) == 0 && fogColor.equals(fogState.fogColor);
     }
 
     @Override