Give each GL drawable its own GLSM context (#2142)

* initial commit for enchant-glint-optimizations

* Fix spacing issues and remove GlintCompatibility.java

README.MD

@@ -101,3 +101,5 @@ Targets GL 3.3+ core profile
   * 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)
+* RGSS Terrain Texture Filtering
+  * Indiesoft for [defold-sharp-sprite](https://github.com/indiesoftby/defold-sharp-sprite), used as the reference implementation under the MIT license

dependencies.gradle.kts

@@ -93,6 +93,7 @@ DependencyHandlerScope.of(dependencies).apply {
     shadowImplementation(project(":lwjgl3-backend")) { isTransitive = false }
     shadowImplementation(project(":sdl-gpu")) { isTransitive = false }
     runtimeOnlyNonPublishable(project(":tracy-client")) { isTransitive = false }
+    devOnlyNonPublishable(libs.async.profiler)
     shadowImplementation(libs.eventbus)
 
     shadowImplementation(libs.jcpp) // Apache 2.0

glsm/build.gradle.kts

@@ -103,6 +103,11 @@ repositories {
     mavenLocal()
 }
 
+val spirvTestRuntime by configurations.creating {
+    isCanBeConsumed = false
+    isCanBeResolved = true
+}
+
 dependencies {
     // MC compile stubs
     compileOnly(sourceSets["stubs"].output)
@@ -133,6 +138,7 @@ dependencies {
     testRuntimeOnly(libs.lwjgl3.spvc) { artifact { classifier = lwjglNatives } }
     testRuntimeOnly(libs.lwjgl3)
     testRuntimeOnly(libs.lwjgl3) { artifact { classifier = lwjglNatives } }
+    spirvTestRuntime(libs.lwjgl3.opengl)
     // @Lwjgl3Aware annotation
     compileOnly(libs.lwjgl3ify) { artifact { classifier = "dev" }; isTransitive = false }
     compileOnly(libs.retrofuturabootstrap) { isTransitive = false }
@@ -309,7 +315,7 @@ val spirvTest by tasks.registering(Test::class) {
     classpath = sourceSets["test"].runtimeClasspath.filter { file ->
         // Strip the LWJGL2 jars - they collide with LWJGL3's sealed org.lwjgl package.
         !file.name.startsWith("lwjgl-2.") && !file.name.startsWith("lwjgl_util-") && !file.name.startsWith("lwjgl-platform-")
-    }
+    }.plus(spirvTestRuntime)
 
     filter {
         includeTestsMatching("com.gtnewhorizons.angelica.glsm.shader.SpirvShaderTranslator*Test")

glsm/src/main/java/com/gtnewhorizons/angelica/config/SystemProperties.java

@@ -37,6 +37,7 @@ public final class SystemProperties {
     public static final boolean SDL_VERIFY_PER_FRAME_UNIFORM_BLOCK = Boolean.getBoolean("angelica.sdlgpu.verifyPerFrameUniformBlock");
     public static final int SDL_FRAMES_IN_FLIGHT = Integer.getInteger("angelica.sdlgpu.framesInFlight", 2);
     public static final boolean DISABLE_SDL_PRESENTER_THREAD = Boolean.getBoolean("angelica.sdlgpu.disablePresenterThread");
+    public static final boolean SDL_DISABLE_IN_PASS_CLEAR = Boolean.getBoolean("angelica.sdlgpu.disableInPassClear");
 
     // Tracy
     public static final boolean TRACY = Boolean.getBoolean("angelica.tracy");
@@ -44,6 +45,11 @@ public final class SystemProperties {
     public static final String TRACY_DIR = System.getProperty("angelica.tracy.dir", "angelica" + File.separator + "natives" + File.separator + "tracy");
     public static final int TRACY_MAX_SRC_LOCS = Math.max(16, Integer.getInteger("angelica.tracy.maxSrcLocs", 4096));
 
+    // Profiling
+    public static final String PROFILE_OPTS = System.getProperty("angelica.profile.opts", "event=wall,interval=5ms,alloc=512k,lock=10ms");
+    public static final String PROFILE_DIR = System.getProperty("angelica.profile.dir", "angelica" + File.separator + "profiles");
+    public static final String PROFILE_OUTPUT = System.getProperty("angelica.profile.output", "");
+
     // Flyby
     public static final String FLYBY_ROUTE = System.getProperty("angelica.flyby.route", "");
     public static final boolean FLYBY_WAIT_FOR_TRACY = Boolean.getBoolean("angelica.flyby.waitForTracy");
@@ -54,7 +60,10 @@ public final class SystemProperties {
     public static final boolean FLYBY_EXIT_WHEN_DONE = Boolean.getBoolean("angelica.flyby.exitWhenDone");
     public static final long FLYBY_TIME_OF_DAY = Math.floorMod(Long.getLong("angelica.flyby.timeOfDay", 6000L), 24000L);
     public static final String FLYBY_COMMANDS = System.getProperty("angelica.flyby.commands", "");
+    public static final String FLYBY_ORIGIN = System.getProperty("angelica.flyby.origin", "");
     public static final FlybyPacing FLYBY_PACING = parseEnum("angelica.flyby.pacing", FlybyPacing.UNCAPPED, FlybyPacing.UNCAPPED, FlybyPacing.class);
+    public static final FlybyWeather FLYBY_WEATHER = parseEnum("angelica.flyby.weather", FlybyWeather.CLEAR, FlybyWeather.CLEAR, FlybyWeather.class);
+    public static final boolean FLYBY_JFR = Boolean.getBoolean("angelica.flyby.jfr");
 
     // Debug
     public static final boolean LWJGL_DEBUG = Boolean.getBoolean("org.lwjgl.util.Debug");
@@ -69,6 +78,7 @@ public final class SystemProperties {
     public static final boolean FFP_TRACE = Boolean.getBoolean("angelica.debug.ffpTrace");
     public static final boolean LOG_DISPLAY_LIST_COMPILATION = Boolean.getBoolean("angelica.debug.displayLists.compilation");
     public static final boolean FORCE_ORPHAN_STREAMING = Boolean.getBoolean("angelica.debug.forceOrphanStreaming");
+    public static final boolean WEATHER_REBUILD_ALWAYS = Boolean.getBoolean("angelica.debug.weatherRebuildAlways");
     public static final String SHADER_DUMP_ROOT = "angelica_dumps";
 
     // Set by us, read by celeritas
@@ -117,6 +127,20 @@ public final class SystemProperties {
         CONFIGURED
     }
 
+    public enum FlybyWeather {
+        CLEAR,
+        RAIN,
+        THUNDER;
+
+        public boolean isRaining() {
+            return this != CLEAR;
+        }
+
+        public boolean isThundering() {
+            return this == THUNDER;
+        }
+    }
+
     private static <E extends Enum<E>> E parseEnum(String key, E whenAbsent, E whenInvalid, Class<E> type) {
         final String raw = System.getProperty(key);
         if (raw == null || raw.isEmpty()) return whenAbsent;

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

@@ -0,0 +1,24 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.stacks.BooleanStateStack;
+
+public final class ClipPlaneBooleanState extends BooleanStateStack {
+
+    private final GLContextState owner;
+    private final int index;
+
+    ClipPlaneBooleanState(GLContextState owner, int index, int glCap) {
+        super(glCap);
+        this.owner = owner;
+        this.index = index;
+    }
+
+    @Override
+    protected void onEnabledChanged() {
+        if (isEnabled()) {
+            owner.clipPlaneEnabledMask |= (1 << index);
+        } else {
+            owner.clipPlaneEnabledMask &= ~(1 << index);
+        }
+    }
+}

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

@@ -117,6 +117,7 @@ public class CompatUniformManager {
 
     private static final class ProgramUniforms {
         final int[] locs;
+        GLContextState owner;
         int lastMvGen = -1, lastMvLinearGen = -1, lastProjGen = -1, lastTexMatGen = -1;
         int lastFragmentGen = -1, lastLightingGen = -1, lastClipPlaneGen = -1;
         ProgramUniforms(int[] locs) { this.locs = locs; }
@@ -161,7 +162,13 @@ public class CompatUniformManager {
         }
 
         if (hasAny) {
-            programUniforms.put(program, new ProgramUniforms(locs));
+            final ProgramUniforms uniforms = new ProgramUniforms(locs);
+            final boolean locked = GLStateManager.acquireDrawLock();
+            try {
+                programUniforms.put(program, uniforms);
+            } finally {
+                if (locked) GLStateManager.releaseDrawLock();
+            }
             GLStateManager.LOGGER.debug("CompatUniformManager: program {} has compat uniforms", program);
         }
     }
@@ -171,16 +178,21 @@ public class CompatUniformManager {
      *
      * @return Whether the program needs emulation (FFP or Iris Program)
      */
-    public static boolean refreshCompatUniforms(int program) {
+    public static boolean refreshCompatUniforms(int program, GLContextState glCtx) {
         final ProgramUniforms pu = programUniforms.get(program);
         if (pu == null) return false;
         final int[] locs = pu.locs;
+        if (pu.owner != glCtx) {
+            pu.owner = glCtx;
+            pu.lastMvGen = pu.lastMvLinearGen = pu.lastProjGen = pu.lastTexMatGen = -1;
+            pu.lastFragmentGen = pu.lastLightingGen = pu.lastClipPlaneGen = -1;
+        }
 
         // Matrix uniforms — skip if this program's storage already holds the current generation
-        final int mvGen = GLStateManager.getMvGeneration();
-        final int mvLinearGen = GLStateManager.getMvLinearGeneration();
-        final int projGen = GLStateManager.getProjGeneration();
-        final int texMatGen = GLStateManager.getTexMatrixGeneration();
+        final int mvGen = glCtx.mvGeneration;
+        final int mvLinearGen = glCtx.mvLinearGeneration;
+        final int projGen = glCtx.projGeneration;
+        final int texMatGen = glCtx.texMatrixGeneration;
         final boolean mvChanged = mvGen != pu.lastMvGen;
         final boolean mvLinearChanged = mvLinearGen != pu.lastMvLinearGen;
         final boolean projChanged = projGen != pu.lastProjGen;
@@ -194,14 +206,14 @@ public class CompatUniformManager {
         }
 
         // Fragment-category uniforms (fog, alpha) — skip if generation unchanged
-        final int fragGen = GLStateManager.getFragmentGeneration();
+        final int fragGen = glCtx.fragmentGeneration;
         if (fragGen != pu.lastFragmentGen) {
             pu.lastFragmentGen = fragGen;
             uploadFragmentUniforms(locs);
         }
 
         // Lighting-derived uniforms (scene color, light sources, material)
-        final int litGen = GLStateManager.getLightingGeneration();
+        final int litGen = glCtx.lightingGeneration;
         if (litGen != pu.lastLightingGen) {
             pu.lastLightingGen = litGen;
             if (locs[LOC_SCENE_COLOR] != -1) uploadSceneColor(locs);
@@ -211,7 +223,7 @@ public class CompatUniformManager {
 
         // Clip plane equations + enabled bool — uploaded when enable state or equations change
         if (locs[LOC_CLIP_PLANES] != -1 || locs[LOC_CLIP_PLANES_ENABLED] != -1) {
-            final int cpGen = GLStateManager.getClipPlaneGeneration();
+            final int cpGen = glCtx.clipPlaneGeneration;
             if (cpGen != pu.lastClipPlaneGen) {
                 pu.lastClipPlaneGen = cpGen;
                 uploadClipPlanes(locs);
@@ -438,7 +450,12 @@ public class CompatUniformManager {
     }
 
     public static void onDeleteProgram(int program) {
-        programUniforms.remove(program);
+        final boolean locked = GLStateManager.acquireDrawLock();
+        try {
+            programUniforms.remove(program);
+        } finally {
+            if (locked) GLStateManager.releaseDrawLock();
+        }
     }
 
     public static boolean hasProgram(int program) {

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

@@ -59,7 +59,7 @@ public class DisplayListIDAllocator {
         numSetElements = 1;
     }
 
-    public int allocRange(int count) {
+    public synchronized int allocRange(int count) {
         if (count <= 0) throw new IllegalArgumentException("count must be > 0");
         if (count == 1) return allocSingle();
         return allocMultiple(count);
@@ -132,7 +132,7 @@ public class DisplayListIDAllocator {
         return numElements;
     }
 
-    public void free(int id) {
+    public synchronized void free(int id) {
         if (id <= 0) return; // ID 0 is reserved
         int idx = id / 32;
         if (idx >= numElements) return;
@@ -147,7 +147,7 @@ public class DisplayListIDAllocator {
         }
     }
 
-    public void freeRange(int base, int count) {
+    public synchronized void freeRange(int base, int count) {
         if (count <= 0 || base <= 0) return;
 
         int startIdx = base / 32;
@@ -166,7 +166,7 @@ public class DisplayListIDAllocator {
         }
     }
 
-    public boolean isAllocated(int id) {
+    public synchronized boolean isAllocated(int id) {
         if (id <= 0) return false;
         int idx = id / 32;
         if (idx >= numSetElements) return false;

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

@@ -79,6 +79,8 @@ public class DisplayListManager {
     // Display list compilation state (current/active context)
     private static int glListMode = 0;
     private static int glListId = -1;
+    private static int recordedStatePushes;
+    private static final DisplayListCommand POP_STATE = GLStateManager::popState;
     private static CommandRecorder currentRecorder = null;  // Command recorder (null when not recording)
     private static volatile Thread recordingThread = null;  // Thread that started recording (for thread-safety)
     private static List<AccumulatedDraw> accumulatedDraws = null;  // Accumulates quad draws for batching
@@ -114,6 +116,7 @@ public class DisplayListManager {
         List<AccumulatedDraw> draws,
         DisplayListCallback callback,
         StackTraceElement[] stackTrace,
+        int recordedStatePushes,
 
         // Debug logging fields (only used when LOG_DISPLAY_LIST_COMPILATION)
         List<String> pendingOps,
@@ -141,7 +144,7 @@ public class DisplayListManager {
     }
 
     public static String describeCurrentCompilation() {
-        if (currentRecorder == null) {
+        if (!isRecording()) {
             return "(not compiling)";
         }
         final String mode = glListMode == GL11.GL_COMPILE_AND_EXECUTE ? "GL_COMPILE_AND_EXECUTE" : "GL_COMPILE";
@@ -150,16 +153,20 @@ public class DisplayListManager {
     }
 
     public static boolean isCompileAndExecute() {
-        return glListMode == GL11.GL_COMPILE_AND_EXECUTE;
+        return isRecording() && glListMode == GL11.GL_COMPILE_AND_EXECUTE;
     }
 
     public static CommandRecorder pauseRecording() {
+        if (Thread.currentThread() != recordingThread) return null;
         final CommandRecorder r = currentRecorder;
         currentRecorder = null;
         return r;
     }
 
     public static void resumeRecording(CommandRecorder r) {
+        if (Thread.currentThread() != recordingThread) {
+            throw new IllegalStateException("Cannot resume another thread's display list compilation");
+        }
         currentRecorder = r;
     }
 
@@ -226,15 +233,15 @@ public class DisplayListManager {
     }
 
     public static int getRecordingListId() {
-        return glListId;
+        return Thread.currentThread() == recordingThread ? glListId : -1;
     }
 
     public static int getListMode() {
-        return glListMode;
+        return Thread.currentThread() == recordingThread ? glListMode : 0;
     }
 
     public static void trackDrawRangeSource(String source) {
-        if (drawRangeSources != null) {
+        if (Thread.currentThread() == recordingThread && drawRangeSources != null) {
             drawRangeSources.add(source);
         }
     }
@@ -451,6 +458,25 @@ public class DisplayListManager {
         currentRecorder.writePopAttrib();
     }
 
+    public static int virtualStateDepth(RecordMode mode) {
+        return mode == RecordMode.COMPILE ? recordedStatePushes : 0;
+    }
+
+    public static void recordPushState(StateSet set) {
+        currentRecorder.writeComplexCommand(set.pushCommand);
+        recordedStatePushes++;
+    }
+
+    public static boolean recordPopStateIfPending() {
+        if (recordedStatePushes > 0) {
+            drawBarrier();
+            currentRecorder.writeComplexCommand(POP_STATE);
+            recordedStatePushes--;
+            return true;
+        }
+        return false;
+    }
+
     public static void recordFogf(int pname, float param) {
         drawBarrier();
         currentRecorder.writeFogf(pname, param);
@@ -739,8 +765,11 @@ public class DisplayListManager {
      * @return true if the display list exists, false otherwise
      */
     public static boolean displayListExists(int list) {
-        if (displayListCache.containsKey(list)) {
-            return true;
+        final boolean locked = GLStateManager.acquireDrawLock();
+        try {
+            if (displayListCache.containsKey(list)) return true;
+        } finally {
+            if (locked) GLStateManager.releaseDrawLock();
         }
         // Check VBOManager for GTNHLib compatibility (negative IDs)
         if (list < -1) {
@@ -756,7 +785,12 @@ public class DisplayListManager {
      * @return The CompiledDisplayList, or null if not found
      */
     public static CompiledDisplayList getDisplayList(int list) {
-        return displayListCache.get(list);
+        final boolean locked = GLStateManager.acquireDrawLock();
+        try {
+            return displayListCache.get(list);
+        } finally {
+            if (locked) GLStateManager.releaseDrawLock();
+        }
     }
 
     /**
@@ -765,71 +799,105 @@ public class DisplayListManager {
      *   GL_COMPILE: Commands are recorded only (not executed), GLSM cache unchanged
      *   GL_COMPILE_AND_EXECUTE: Commands are recorded AND executed (GLSM cache updated)
      */
-    public static void glNewList(int list, int mode) {
-        // Handle nested compilation - push current context onto stack
+    public static synchronized void glNewList(int list, int mode) {
+        final Thread recorder = recordingThread;
+        if (recorder != null && recorder != Thread.currentThread()) {
+            throw new IllegalStateException("glNewList(" + list + ") on " + Thread.currentThread().getName() + " while " + recorder.getName() + " is compiling a display list");
+        }
         final boolean isNested = glListMode > 0;
+        final int captureDepth = TessellatorManager.getDirectCaptureDepth();
+        boolean pushed = false;
+        if (!isNested) recordingThread = Thread.currentThread();
+        try {
+            if (isNested) {
+                flushAll();
+                final CompilationContext parentContext = new CompilationContext(
+                    glListId, glListMode, currentRecorder, accumulatedDraws, transformCallback,
+                    compilationStackTrace, recordedStatePushes, pendingTransformOps, multMatrixSources, drawRangeSources
+                );
+                compilationStack.push(parentContext);
+                pushed = true;
+            }
 
-        if (isNested) {
-            flushAll();
-            // Nested display list compilation violates OpenGL spec, but some of our optimizations require it
-            // Save current compilation context and start fresh for nested list
-            final CompilationContext parentContext = new CompilationContext(
-                glListId, glListMode, currentRecorder, accumulatedDraws, transformCallback,
-                compilationStackTrace, pendingTransformOps, multMatrixSources, drawRangeSources
-            );
-            compilationStack.push(parentContext);
+            glListId = list;
+            glListMode = mode;
+            currentRecorder = new CommandRecorder();
+            accumulatedDraws = new ArrayList<>(8);
+            transformCallback = new DisplayListCallback();
+            recordedStatePushes = 0;
+            compilationStackTrace = SystemProperties.LOG_DISPLAY_LIST_COMPILATION ? Thread.currentThread().getStackTrace() : null;
+
+            if (SystemProperties.LOG_DISPLAY_LIST_COMPILATION) {
+                pendingTransformOps = new ArrayList<>();
+                multMatrixSources = new ArrayList<>();
+                drawRangeSources = new ArrayList<>();
+            } else {
+                pendingTransformOps = null;
+                multMatrixSources = null;
+                drawRangeSources = null;
+            }
+
+            TessellatorManager.startCapturingDirect(transformCallback);
+        } catch (RuntimeException | Error failure) {
+            try {
+                if (TessellatorManager.getDirectCaptureDepth() > captureDepth) TessellatorManager.stopCapturingDirect();
+            } catch (RuntimeException | Error cleanup) {
+                failure.addSuppressed(cleanup);
+            }
+            try {
+                if (pushed) {
+                    final CommandRecorder parent = compilationStack.peek().recorder();
+                    try {
+                        if (currentRecorder != null && currentRecorder != parent) currentRecorder.delete();
+                    } finally {
+                        popCompilationContext();
+                    }
+                } else if (!isNested) {
+                    try {
+                        if (currentRecorder != null) currentRecorder.delete();
+                    } finally {
+                        resetCompilationState();
+                    }
+                }
+            } catch (RuntimeException | Error cleanup) {
+                failure.addSuppressed(cleanup);
+            }
+            throw failure;
         }
-
-        // Initialize fresh context for this (possibly nested) list
-        glListId = list;
-        glListMode = mode;
-        recordingThread = Thread.currentThread();  // Track which thread is recording
-        currentRecorder = new CommandRecorder();  // Create command recorder
-        accumulatedDraws = new ArrayList<>(8);   // Fewer draws than commands typically
-        transformCallback = new DisplayListCallback();
-        compilationStackTrace = SystemProperties.LOG_DISPLAY_LIST_COMPILATION ? Thread.currentThread().getStackTrace() : null;
-
-        // Initialize debug logging fields (only when logging enabled)
-        if (SystemProperties.LOG_DISPLAY_LIST_COMPILATION) {
-            pendingTransformOps = new ArrayList<>();
-            multMatrixSources = new ArrayList<>();
-            drawRangeSources = new ArrayList<>();
-        } else {
-            pendingTransformOps = null;
-            multMatrixSources = null;
-            drawRangeSources = null;
-        }
-
-        TessellatorManager.startCapturingDirect(transformCallback);
     }
 
     /**
      * End display list compilation and build optimized/unoptimized versions.
      */
-    public static void glEndList() {
+    public static synchronized void glEndList() {
+        final Thread recorder = recordingThread;
+        if (recorder != null && recorder != Thread.currentThread()) {
+            throw new IllegalStateException("glEndList on " + Thread.currentThread().getName() + " while " + recorder.getName() + " is compiling a display list");
+        }
         if (glListMode == 0) {
             GLStateManager.warnOnce("endlist-outside", "glEndList called outside of a display list!");
             return;
         }
         if (Tracy.ENABLED) Tracy.beginZone(Z_GL_LIST_COMPILE);
         try {
+            TessellatorManager.stopCapturingDirect();
             finishCurrentList();
         } finally {
             if (Tracy.ENABLED) Tracy.endZone();
-            // Non-null here means finishCurrentList threw before transferring or releasing
-            // ownership of the recorder.
-            if (currentRecorder != null) {
-                currentRecorder.delete();
+            try {
+                if (currentRecorder != null) currentRecorder.delete();
+            } finally {
+                popCompilationContext();
             }
-            // Must always run, even when compilation fails - a leaked context leaves
-            // isRecording() true forever and every guarded GL call throws afterward.
-            popCompilationContext();
         }
     }
 
     private static void finishCurrentList() {
-        // Stop compiling mode (works for both root and nested lists now)
-        TessellatorManager.stopCapturingDirect();
+        boolean unbalancedStatePush = false;
+        while (recordPopStateIfPending()) unbalancedStatePush = true;
+        if (unbalancedStatePush) {
+            GLStateManager.warnOnce("unbalanced-state-push", "Display list {} ended with unpopped internal state pushes - closing them", glListId);
+        }
 
         flushAll();
 
@@ -921,6 +989,7 @@ public class DisplayListManager {
             accumulatedDraws = parentContext.draws;
             transformCallback = parentContext.callback;
             compilationStackTrace = parentContext.stackTrace;
+            recordedStatePushes = parentContext.recordedStatePushes;
             pendingTransformOps = parentContext.pendingOps;
             multMatrixSources = parentContext.matrixSources;
             drawRangeSources = parentContext.drawSources;
@@ -936,7 +1005,6 @@ public class DisplayListManager {
     /** Clear all root-level compilation state back to "not recording". */
     private static void resetCompilationState() {
         currentRecorder = null;
-        recordingThread = null;
         accumulatedDraws = null;
         pendingDraw = null;
         transformCallback = null;
@@ -946,9 +1014,14 @@ public class DisplayListManager {
         drawRangeSources = null;
         glListId = -1;
         glListMode = 0;
+        recordedStatePushes = 0;
+        recordingThread = null;
     }
 
-    public static void abortCompilation() {
+    public static synchronized void abortCompilation() {
+        if (recordingThread != null && recordingThread != Thread.currentThread()) {
+            throw new IllegalStateException("Cannot abort another thread's display list compilation");
+        }
         if (glListMode == 0 && compilationStack.isEmpty()) {
             return;
         }
@@ -976,7 +1049,7 @@ public class DisplayListManager {
     }
 
     public static void abortIfLeaked() {
-        if (glListMode != 0 || !compilationStack.isEmpty()) {
+        if (Thread.currentThread() == recordingThread && (glListMode != 0 || !compilationStack.isEmpty())) {
             GLStateManager.warnOnce("frame-leak", "Display list {} left open across a frame boundary - aborting to recover", glListId);
             abortCompilation();
         }
@@ -1012,7 +1085,7 @@ public class DisplayListManager {
      * Execute a compiled display list.
      */
     public static void glCallList(int list) {
-        if (currentRecorder != null) {
+        if (isRecording()) {
             recordCallList(list);
 
             if (getListMode() != GL11.GL_COMPILE) {

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

@@ -3,18 +3,13 @@ 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 com.gtnewhorizons.angelica.glsm.stacks.CowStateStack;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL13;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashMap;
 import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
 import java.util.Set;
 
 public class Feature {
@@ -23,52 +18,49 @@ public class Feature {
         GL13.GL_MULTISAMPLE_BIT, GL11.GL_PIXEL_MODE_BIT, GL11.GL_POINT_BIT, GL11.GL_POLYGON_BIT, GL11.GL_POLYGON_STIPPLE_BIT, GL11.GL_SCISSOR_BIT,
         GL11.GL_STENCIL_BUFFER_BIT, GL11.GL_TEXTURE_BIT, GL11.GL_TRANSFORM_BIT, GL11.GL_VIEWPORT_BIT };
 
-    static final Int2ObjectMap<List<IStateStack<?>>> maskToFeaturesMap = new Int2ObjectOpenHashMap<>();
-    static final Int2ObjectMap<IStateStack<?>[]> maskToNonBooleanStacksMap = new Int2ObjectOpenHashMap<>();
+    private static final long[] NO_MEMBERS = new long[0];
 
-    static List<IStateStack<?>> maskToFeatures(int mask) {
-        if(maskToFeaturesMap.containsKey(mask)) {
-            return maskToFeaturesMap.get(mask);
-        }
+    private static final Int2ObjectMap<long[]> maskToMembersMap = new Int2ObjectOpenHashMap<>();
 
-        final Set<IStateStack<?>> features = new HashSet<>();
-
-        for(int attrib : Feature.supportedAttribs) {
-            if((mask & attrib) == attrib) {
-                features.addAll(getFeatures(attrib));
-            }
-        }
-
-        final List<IStateStack<?>> asList = new ArrayList<>(features);
-
-        maskToFeaturesMap.put(mask, asList);
-        return asList;
-    }
-
-    /**
-     * Returns only non-BooleanStateStack instances for the given mask.
-     * These use traditional push/pop without global depth tracking.
-     */
-    static IStateStack<?>[] maskToNonBooleanStacks(int mask) {
-        IStateStack<?>[] cached = maskToNonBooleanStacksMap.get(mask);
+    static long[] maskToMembers(int mask) {
+        final long[] cached = maskToMembersMap.get(mask);
         if (cached != null) {
             return cached;
         }
 
-        final List<IStateStack<?>> all = maskToFeatures(mask);
-        final List<IStateStack<?>> nonBooleans = new ArrayList<>();
-        for (int i = 0; i < all.size(); i++) {
-            final IStateStack<?> stack = all.get(i);
-            if (!(stack instanceof BooleanStateStack)) {
-                nonBooleans.add(stack);
+        long[] result = NO_MEMBERS;
+        for (int attrib : Feature.supportedAttribs) {
+            if ((mask & attrib) == attrib) {
+                result = union(result, attribToMembers.get(attrib));
             }
         }
-        cached = nonBooleans.toArray(new IStateStack<?>[0]);
-        maskToNonBooleanStacksMap.put(mask, cached);
-        return cached;
+
+        maskToMembersMap.put(mask, result);
+        return result;
     }
 
-    private static final Map<Integer, Set<IStateStack<?>>> attribToFeatures = new HashMap<>();
+    private static long[] union(long[] a, long[] b) {
+        if (b == null || b.length == 0) return a;
+        if (a.length == 0) return b.clone();
+        final long[] result = new long[Math.max(a.length, b.length)];
+        System.arraycopy(a, 0, result, 0, a.length);
+        for (int i = 0; i < b.length; i++) result[i] |= b[i];
+        return result;
+    }
+
+    private static long[] toMembers(Set<IStateStack<?>> stacks) {
+        if (stacks.isEmpty()) return NO_MEMBERS;
+        int max = 0;
+        for (IStateStack<?> s : stacks) max = Math.max(max, ((CowStateStack<?>) s).stackId());
+        final long[] bits = new long[(max >> 6) + 1];
+        for (IStateStack<?> s : stacks) {
+            final int id = ((CowStateStack<?>) s).stackId();
+            bits[id >> 6] |= 1L << id;
+        }
+        return bits;
+    }
+
+    private static final Int2ObjectMap<long[]> attribToMembers = new Int2ObjectOpenHashMap<>();
 
     /**
      * Helper method to add all texture gen states (S, T, R, Q) for all texture units to a collection.
@@ -84,6 +76,8 @@ public class Feature {
     }
 
     static {
+        final Int2ObjectMap<Set<IStateStack<?>>> attribToFeatures = new Int2ObjectOpenHashMap<>();
+
         attribToFeatures.put(GL11.GL_COLOR_BUFFER_BIT, ImmutableSet.of(
               GLStateManager.getAlphaTest()
             , GLStateManager.getAlphaState()
@@ -191,11 +185,25 @@ public class Feature {
 
         attribToFeatures.put(GL11.GL_ENABLE_BIT, enableBits);
         attribToFeatures.put(GL11.GL_EVAL_BIT, ImmutableSet.of(
-            // GL_MAP1_x enable bits, where x is a map type
-            // GL_MAP2_x enable bits, where x is a map type
-            // 1D grid endpoints and divisions
-            // 2D grid endpoints and divisions
-            // GL_AUTO_NORMAL enable bit
+              GLStateManager.getAutoNormalState()
+            , GLStateManager.getMap1Color4State()
+            , GLStateManager.getMap1IndexState()
+            , GLStateManager.getMap1NormalState()
+            , GLStateManager.getMap1TextureCoord1State()
+            , GLStateManager.getMap1TextureCoord2State()
+            , GLStateManager.getMap1TextureCoord3State()
+            , GLStateManager.getMap1TextureCoord4State()
+            , GLStateManager.getMap1Vertex3State()
+            , GLStateManager.getMap1Vertex4State()
+            , GLStateManager.getMap2Color4State()
+            , GLStateManager.getMap2IndexState()
+            , GLStateManager.getMap2NormalState()
+            , GLStateManager.getMap2TextureCoord1State()
+            , GLStateManager.getMap2TextureCoord2State()
+            , GLStateManager.getMap2TextureCoord3State()
+            , GLStateManager.getMap2TextureCoord4State()
+            , GLStateManager.getMap2Vertex3State()
+            , GLStateManager.getMap2Vertex4State()
         ));
         attribToFeatures.put(GL11.GL_FOG_BIT, ImmutableSet.of(
               GLStateManager.getFogMode()
@@ -258,10 +266,10 @@ public class Feature {
             // GL_LIST_BASE setting
         ));
         attribToFeatures.put(GL13.GL_MULTISAMPLE_BIT, ImmutableSet.of(
-            // GL_MULTISAMPLE enable bit
-            // GL_SAMPLE_ALPHA_TO_COVERAGE flag
-            // GL_SAMPLE_ALPHA_TO_ONE flag
-            // GL_SAMPLE_COVERAGE flag
+              GLStateManager.getMultisampleState()
+            , GLStateManager.getSampleAlphaToCoverageState()
+            , GLStateManager.getSampleAlphaToOneState()
+            , GLStateManager.getSampleCoverageState()
             // GL_SAMPLE_COVERAGE_VALUE value
             // GL_SAMPLE_COVERAGE_INVERT value
         ));
@@ -294,7 +302,7 @@ public class Feature {
         ));
         attribToFeatures.put(GL11.GL_SCISSOR_BIT, ImmutableSet.of(
               GLStateManager.getScissorTest()
-            // Scissor box
+            , GLStateManager.getScissorState()
         ));
         attribToFeatures.put(GL11.GL_STENCIL_BUFFER_BIT, ImmutableSet.of(
               GLStateManager.getStencilTest()
@@ -327,22 +335,24 @@ public class Feature {
 
         attribToFeatures.put(GL11.GL_TEXTURE_BIT, textureAttribs);
 
-        attribToFeatures.put(GL11.GL_TRANSFORM_BIT, ImmutableSet.of(
+        final Set<IStateStack<?>> transformAttribs = new HashSet<>(ImmutableSet.of(
             // Coefficients of the six clipping planes
-            
+
               GLStateManager.getMatrixMode()
             , GLStateManager.getNormalizeState()
             , GLStateManager.getRescaleNormalState()
         ));
+        for(int i = 0; i < GLStateManager.getClipPlaneStates().length; i++) {
+            transformAttribs.add(GLStateManager.getClipPlaneStates()[i]);
+        }
+        attribToFeatures.put(GL11.GL_TRANSFORM_BIT, transformAttribs);
         attribToFeatures.put(GL11.GL_VIEWPORT_BIT, ImmutableSet.of(
-            
+
             GLStateManager.getViewportState()
         ));
+
+        for (Int2ObjectMap.Entry<Set<IStateStack<?>>> entry : attribToFeatures.int2ObjectEntrySet()) {
+            attribToMembers.put(entry.getIntKey(), toMembers(entry.getValue()));
+        }
     }
-
-    public static Set<IStateStack<?>> getFeatures(int attrib) {
-        return attribToFeatures.getOrDefault(attrib, Collections.emptySet());
-    }
-
-
 }

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

@@ -1,6 +1,5 @@
 package com.gtnewhorizons.angelica.glsm;
 
-import com.gtnewhorizons.angelica.glsm.ffp.VAOManager;
 import com.gtnewhorizons.angelica.glsm.recording.ImmediateModeRecorder;
 import com.gtnewhorizons.angelica.glsm.states.ViewportState;
 import org.joml.Matrix4f;
@@ -48,6 +47,10 @@ public class FeedbackManager {
         return renderMode == GL11.GL_FEEDBACK;
     }
 
+    public static int getRenderMode() {
+        return renderMode;
+    }
+
     public static void glFeedbackBuffer(int type, FloatBuffer buffer) {
         if (renderMode == GL11.GL_FEEDBACK) {
             GLStateManager.LOGGER.error("glFeedbackBuffer called while already in feedback mode");
@@ -126,30 +129,32 @@ public class FeedbackManager {
         feedbackVertex(winX, winY, winZ, winW);
     }
 
-    private static int positionStride() {
-        final int s = VAOManager.getAttribEffectiveStride(0);
+    private static int positionStride(GLContextState glCtx) {
+        final int s = glCtx.vaos.attribEffectiveStride(0);
         return (s != 0) ? s : 12;
     }
 
-    private static long positionOffset() {
-        return VAOManager.getAttribOffset(0);
+    private static long positionOffset(GLContextState glCtx) {
+        return glCtx.vaos.attribOffset(0);
     }
 
     public static void processDrawArrays(int mode, int first, int count) {
         computeMVP();
-        final int stride = positionStride();
-        final long posOffset = positionOffset();
+        final GLContextState glCtx = GLStateManager.ctx();
+        final int stride = positionStride(glCtx);
+        final long posOffset = positionOffset(glCtx);
         final int byteCount = count * stride;
         ensureReadbackCapacity(byteCount);
         readbackBuf.clear().limit(byteCount);
-        readPositionBuffer((long) first * stride + posOffset, readbackBuf);
+        readPositionBuffer((long) first * stride + posOffset, readbackBuf, glCtx);
 
         emitAllPrimitives(mode, count, i -> i, stride);
     }
 
     public static void processDrawElements(int mode, int indexCount, int type, long eboOffset) {
         computeMVP();
-        final int stride = positionStride();
+        final GLContextState glCtx = GLStateManager.ctx();
+        final int stride = positionStride(glCtx);
 
         final int elementSize = GLTypes.sizeBytes(type);
         final int indexByteCount = indexCount * elementSize;
@@ -165,12 +170,12 @@ public class FeedbackManager {
             if (idx > maxIdx) maxIdx = idx;
         }
 
-        final long posOffset = positionOffset();
+        final long posOffset = positionOffset(glCtx);
         final int vertexCount = maxIdx - minIdx + 1;
         final int byteCount = vertexCount * stride;
         ensureReadbackCapacity(byteCount);
         readbackBuf.clear().limit(byteCount);
-        readPositionBuffer((long) minIdx * stride + posOffset, readbackBuf);
+        readPositionBuffer((long) minIdx * stride + posOffset, readbackBuf, glCtx);
 
         final int base = minIdx;
         emitAllPrimitives(mode, indexCount, i -> ImmediateModeRecorder.readIndex(indexBuf, type, 0, i) - base, stride);
@@ -204,7 +209,8 @@ public class FeedbackManager {
 
     private static void processDrawElementsImpl(int mode, int count, IndexReader reader) {
         computeMVP();
-        final int stride = positionStride();
+        final GLContextState glCtx = GLStateManager.ctx();
+        final int stride = positionStride(glCtx);
 
         int minIdx = Integer.MAX_VALUE, maxIdx = Integer.MIN_VALUE;
         for (int i = 0; i < count; i++) {
@@ -213,7 +219,7 @@ public class FeedbackManager {
             if (idx > maxIdx) maxIdx = idx;
         }
 
-        readVerticesFromVBO(minIdx, maxIdx, stride);
+        readVerticesFromVBO(minIdx, maxIdx, stride, glCtx);
         final int base = minIdx;
         emitAllPrimitives(mode, count, i -> reader.read(i) - base, stride);
     }
@@ -245,18 +251,18 @@ public class FeedbackManager {
         }
     }
 
-    private static void readVerticesFromVBO(int minIdx, int maxIdx, int stride) {
-        final long posOffset = positionOffset();
+    private static void readVerticesFromVBO(int minIdx, int maxIdx, int stride, GLContextState glCtx) {
+        final long posOffset = positionOffset(glCtx);
         final int vertexCount = maxIdx - minIdx + 1;
         final int byteCount = vertexCount * stride;
         ensureReadbackCapacity(byteCount);
         readbackBuf.clear().limit(byteCount);
-        readPositionBuffer((long) minIdx * stride + posOffset, readbackBuf);
+        readPositionBuffer((long) minIdx * stride + posOffset, readbackBuf, glCtx);
     }
 
-    private static void readPositionBuffer(long offset, ByteBuffer destination) {
-        final int positionVbo = VAOManager.getAttribVBO(0);
-        final int previousVbo = GLStateManager.getBoundVBO();
+    private static void readPositionBuffer(long offset, ByteBuffer destination, GLContextState glCtx) {
+        final int positionVbo = glCtx.vaos.attribVBO(0);
+        final int previousVbo = glCtx.boundVBO;
 
         if (positionVbo != 0 && positionVbo != previousVbo) {
             GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, positionVbo);

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

@@ -3,13 +3,14 @@ package com.gtnewhorizons.angelica.glsm;
 import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import it.unimi.dsi.fastutil.ints.Int2IntMap;
 import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
-import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
-import it.unimi.dsi.fastutil.ints.IntSet;
 import com.gtnewhorizons.angelica.glsm.stacks.AlphaStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.BlendStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.BooleanStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.Color4Stack;
 import com.gtnewhorizons.angelica.glsm.stacks.ColorMaskStack;
+import com.gtnewhorizons.angelica.glsm.stacks.CowDepths;
+import com.gtnewhorizons.angelica.glsm.stacks.CowDispatch;
+import com.gtnewhorizons.angelica.glsm.stacks.CowStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.DepthStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.FogStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.IntegerStateStack;
@@ -20,8 +21,11 @@ import com.gtnewhorizons.angelica.glsm.stacks.MaterialStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.MatrixModeStack;
 import com.gtnewhorizons.angelica.glsm.stacks.PointStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.PolygonStateStack;
+import com.gtnewhorizons.angelica.glsm.stacks.ScissorStateStack;
+import com.gtnewhorizons.angelica.glsm.stacks.StackIdAllocator;
 import com.gtnewhorizons.angelica.glsm.stacks.StencilStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.ViewPortStateStack;
+import com.gtnewhorizons.angelica.glsm.states.AlphaState;
 import com.gtnewhorizons.angelica.glsm.states.BlendState;
 import com.gtnewhorizons.angelica.glsm.states.ClipPlaneState;
 import com.gtnewhorizons.angelica.glsm.states.Color4;
@@ -29,25 +33,41 @@ import com.gtnewhorizons.angelica.glsm.states.PixelUnpackState;
 import com.gtnewhorizons.angelica.glsm.states.ImageUnitArray;
 import com.gtnewhorizons.angelica.glsm.states.SamplerUnitArray;
 import com.gtnewhorizons.angelica.glsm.states.TextureUnitArray;
-import it.unimi.dsi.fastutil.ints.IntArrayList;
-import it.unimi.dsi.fastutil.ints.IntStack;
+import com.gtnewhorizons.angelica.glsm.ffp.Instancing;
+import com.gtnewhorizons.angelica.glsm.ffp.ShaderManager;
+import com.gtnewhorizons.angelica.glsm.ffp.VAOManager;
+import com.gtnewhorizons.angelica.glsm.streaming.StreamingVaos;
+import org.joml.Matrix4d;
+import org.joml.Matrix4f;
 import org.joml.Matrix4fStack;
+import org.joml.Vector4f;
 import org.lwjgl.BufferUtils;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL12;
 import org.lwjgl.opengl.GL13;
 import org.lwjgl.opengl.GL14;
+import org.lwjgl.opengl.GL30;
 
 import java.nio.DoubleBuffer;
 import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
 import java.util.ArrayList;
 import java.util.List;
 
-class GLContextState {
+public class GLContextState {
+    private final List<IStateStack<?>> allStacksBuilder = new ArrayList<>();
+    public IStateStack<?>[] allStacks;
     final List<BooleanStateStack> allBooleanStates = new ArrayList<>();
 
     private BooleanStateStack track(BooleanStateStack s) {
+        s.setStackId(StackIdAllocator.nextId());
         allBooleanStates.add(s);
+        allStacksBuilder.add(s);
+        return s;
+    }
+
+    private <T extends IStateStack<?>> T member(T s) {
+        allStacksBuilder.add(s);
         return s;
     }
 
@@ -68,6 +88,7 @@ class GLContextState {
     public int colorGeneration;
     // clip plane equation changes
     public int clipPlaneGeneration;
+    public int clipPlaneEnabledMask;
     public float overlayR = 0.0f;
     public float overlayG = 0.0f;
     public float overlayB = 0.0f;
@@ -84,10 +105,15 @@ class GLContextState {
     public boolean unit23TexCoordSetDuringDraw = false;
     public int maxBoundTextureUnit = 0;
     public int maxBoundImageUnit = 0;
-    public final IntStack attribs = new IntArrayList(GLStateManager.MAX_ATTRIB_STACK_DEPTH);
+    public final StateSet[] attribSets = new StateSet[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
     public int attribDepth = 0;
-    @SuppressWarnings("unchecked")
-    public final List<IStateStack<?>>[] modifiedAtDepth = new List[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
+    public CowStateStack<?>[] stackById;
+    public CowDepths[] depthsById;
+    public int[] restoreBitById;
+    public int[] restoreUnitById;
+    public byte[] kindById;
+    public int[][] modifiedIds;
+    public int[] modifiedCount;
     public final int[] savedMvGen = new int[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
     public final int[] savedMvLinearGen = new int[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
     public final int[] savedProjGen = new int[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
@@ -97,29 +123,31 @@ class GLContextState {
     public final int[] savedColorGen = new int[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
     public final int[] savedNormalGen = new int[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
     public final int[] savedTexCoordGen = new int[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-    public final IntegerStateStack activeTextureUnit = new IntegerStateStack(0);
+    public final IntegerStateStack activeTextureUnit = member(new IntegerStateStack(0, StackIdAllocator.nextId()).restoreBit(StateSet.R_ACTIVE_UNIT));
     public int clientActiveTextureUnit = 0;
-    public final IntegerStateStack shadeModelState = new IntegerStateStack(GL11.GL_SMOOTH);
+    public final IntegerStateStack shadeModelState = member(new IntegerStateStack(GL11.GL_SMOOTH, StackIdAllocator.nextId()));
     public final TextureUnitArray textures = new TextureUnitArray();
     public final ImageUnitArray imageUnits = new ImageUnitArray();
     public final SamplerUnitArray samplerUnits = new SamplerUnitArray();
-    public final BlendStateStack blendState = new BlendStateStack();
+    public final BlendStateStack blendState = member(new BlendStateStack(StackIdAllocator.nextId()));
     public final BooleanStateStack blendMode = track(new BooleanStateStack(GL11.GL_BLEND));
     public final BooleanStateStack scissorTest = track(new BooleanStateStack(GL11.GL_SCISSOR_TEST));
-    public final DepthStateStack depthState = new DepthStateStack();
+    public final BooleanStateStack rasterizerDiscard = track(new BooleanStateStack(GL30.GL_RASTERIZER_DISCARD));
+    public final DepthStateStack depthState = member(new DepthStateStack(StackIdAllocator.nextId()));
     public final BooleanStateStack depthTest = track(new BooleanStateStack(GL11.GL_DEPTH_TEST));
-    public final FogStateStack fogState = new FogStateStack();
+    public final FogStateStack fogState = member(new FogStateStack(StackIdAllocator.nextId()));
     public final BooleanStateStack fogMode = track(new BooleanStateStack(GL11.GL_FOG, false, true));
-    public final Color4Stack color = new Color4Stack();
+    public final Color4Stack color = member(new Color4Stack(StackIdAllocator.nextId()));
     // GL_CURRENT_SECONDARY_COLOR - alpha is always 1 and unused, the color sum only adds RGB
-    public final Color4Stack secondaryColor = new Color4Stack(new Color4(0.0F, 0.0F, 0.0F, 1.0F));
+    public final Color4Stack secondaryColor = member(new Color4Stack(StackIdAllocator.nextId(), new Color4(0.0F, 0.0F, 0.0F, 1.0F)).restoreBit(StateSet.R_SECONDARY_COLOR));
     public final BooleanStateStack colorSumState = track(new BooleanStateStack(GL14.GL_COLOR_SUM, false, true));
-    public final Color4Stack clearColor = new Color4Stack(new Color4(0.0F, 0.0F, 0.0F, 0.0F));
-    public final ColorMaskStack colorMask = new ColorMaskStack();
-    public final IntegerStateStack drawBuffer = new IntegerStateStack(GLStateManager.DEFAULT_DRAW_BUFFER);
-    public final IntegerStateStack logicOpMode = new IntegerStateStack(GL11.GL_COPY);
+    public final Color4Stack clearColor = member(new Color4Stack(StackIdAllocator.nextId(), new Color4(0.0F, 0.0F, 0.0F, 0.0F)).restoreBit(StateSet.R_CLEAR_COLOR));
+    public final ColorMaskStack colorMask = member(new ColorMaskStack(StackIdAllocator.nextId()));
+    public final IntegerStateStack drawBuffer = member(new IntegerStateStack(GLStateManager.DEFAULT_DRAW_BUFFER, StackIdAllocator.nextId()).restoreBit(StateSet.R_DRAW_BUFFER));
+    public final IntegerStateStack logicOpMode = member(new IntegerStateStack(GL11.GL_COPY, StackIdAllocator.nextId()).restoreBit(StateSet.R_LOGIC_OP));
     public final BooleanStateStack cullState = track(new BooleanStateStack(GL11.GL_CULL_FACE));
-    public final AlphaStateStack alphaState = new AlphaStateStack();
+    public final AlphaState restoredAlphaScratch = new AlphaState();
+    public final AlphaStateStack alphaState = member(new AlphaStateStack(StackIdAllocator.nextId()));
     public final BooleanStateStack alphaTest = track(new BooleanStateStack(GL11.GL_ALPHA_TEST, false, true));
     public final BooleanStateStack lightingState = track(new BooleanStateStack(GL11.GL_LIGHTING, false, true));
     public final BooleanStateStack rescaleNormalState = track(new BooleanStateStack(GL12.GL_RESCALE_NORMAL, false, true));
@@ -140,10 +168,10 @@ class GLContextState {
     public final BooleanStateStack polygonOffsetPointState = track(new BooleanStateStack(GL11.GL_POLYGON_OFFSET_POINT));
     public final BooleanStateStack polygonOffsetLineState = track(new BooleanStateStack(GL11.GL_POLYGON_OFFSET_LINE));
     public final BooleanStateStack polygonOffsetFillState = track(new BooleanStateStack(GL11.GL_POLYGON_OFFSET_FILL));
-    public final LineStateStack lineState = new LineStateStack();
-    public final PointStateStack pointState = new PointStateStack();
-    public final PolygonStateStack polygonState = new PolygonStateStack();
-    public final StencilStateStack stencilState = new StencilStateStack();
+    public final LineStateStack lineState = member(new LineStateStack(StackIdAllocator.nextId()));
+    public final PointStateStack pointState = member(new PointStateStack(StackIdAllocator.nextId()));
+    public final PolygonStateStack polygonState = member(new PolygonStateStack(StackIdAllocator.nextId()));
+    public final StencilStateStack stencilState = member(new StencilStateStack(StackIdAllocator.nextId()));
     public int stencilBitMask = 0xFFFFFFFF;
     public final BooleanStateStack autoNormalState = track(new BooleanStateStack(GL11.GL_AUTO_NORMAL, false, true));
     public final BooleanStateStack map1Color4State = track(new BooleanStateStack(GL11.GL_MAP1_COLOR_4, false, true));
@@ -168,19 +196,21 @@ class GLContextState {
     public final ClipPlaneState clipPlaneState = new ClipPlaneState();
     public final FloatBuffer queryScratch = BufferUtils.createFloatBuffer(16);
     public final DoubleBuffer queryScratchDouble = BufferUtils.createDoubleBuffer(16);
-    public final MatrixModeStack matrixMode = new MatrixModeStack();
+    public final MatrixModeStack matrixMode = member(new MatrixModeStack(StackIdAllocator.nextId()));
     public final Matrix4fStack modelViewMatrix = new Matrix4fStack(GLStateManager.MAX_MODELVIEW_STACK_DEPTH);
     public final Matrix4fStack projectionMatrix = new Matrix4fStack(GLStateManager.MAX_PROJECTION_STACK_DEPTH);
     public final BooleanStateStack[] lightStates = new BooleanStateStack[8];
     public final LightStateStack[] lightDataStates = new LightStateStack[8];
     public final BooleanStateStack colorMaterial = track(new BooleanStateStack(GL11.GL_COLOR_MATERIAL, false, true));
-    public final IntegerStateStack colorMaterialFace = new IntegerStateStack(GL11.GL_FRONT_AND_BACK);
-    public final IntegerStateStack colorMaterialParameter = new IntegerStateStack(GL11.GL_AMBIENT_AND_DIFFUSE);
-    public final LightModelStateStack lightModel = new LightModelStateStack();
-    public final MaterialStateStack frontMaterial = new MaterialStateStack(GL11.GL_FRONT);
-    public final MaterialStateStack backMaterial = new MaterialStateStack(GL11.GL_BACK);
-    public final ViewPortStateStack viewportState = new ViewPortStateStack();
+    public final IntegerStateStack colorMaterialFace = member(new IntegerStateStack(GL11.GL_FRONT_AND_BACK, StackIdAllocator.nextId()));
+    public final IntegerStateStack colorMaterialParameter = member(new IntegerStateStack(GL11.GL_AMBIENT_AND_DIFFUSE, StackIdAllocator.nextId()));
+    public final LightModelStateStack lightModel = member(new LightModelStateStack(StackIdAllocator.nextId()));
+    public final MaterialStateStack frontMaterial = member(new MaterialStateStack(GL11.GL_FRONT, StackIdAllocator.nextId()));
+    public final MaterialStateStack backMaterial = member(new MaterialStateStack(GL11.GL_BACK, StackIdAllocator.nextId()));
+    public final ViewPortStateStack viewportState = member(new ViewPortStateStack(StackIdAllocator.nextId()));
+    public final ScissorStateStack scissorState = member(new ScissorStateStack(StackIdAllocator.nextId()));
     public int activeProgram = 0;
+    public final IntegerStateStack programStack = member(new IntegerStateStack(0, StackIdAllocator.nextId()));
     public int listBase = 0;
     public int boundVBO;
     public int boundVAO;
@@ -189,33 +219,80 @@ class GLContextState {
     public int boundCopyReadBuffer;
     public int boundCopyWriteBuffer;
     public final Int2IntMap boundOtherBuffers = new Int2IntOpenHashMap();
-    public final IntSet writeMappedBuffers = new IntOpenHashSet();
     public PixelUnpackState pixelUnpackState = PixelUnpackState.DEFAULT;
     public final int[] clientAttribSavedTextureUnit = new int[GLStateManager.CLIENT_ATTRIB_STACK_DEPTH];
     public final int[] clientAttribSavedVertexFlags = new int[GLStateManager.CLIENT_ATTRIB_STACK_DEPTH];
     public int clientAttribStackPointer = 0;
-    public final boolean[] restoreUnitChanged = new boolean[GLStateManager.MAX_TEXTURE_UNITS];
-    public boolean restoreDepthChanged, restoreBlendChanged, restoreColorMaskChanged, restoreClearColorChanged, restoreDrawBufferChanged, restoreLogicOpChanged, restoreStencilChanged, restoreViewportChanged, restoreLineChanged, restorePointChanged, restorePolygonChanged, restoreActiveUnitChanged, restoreSecondaryColorChanged;
+    public int restoreChangedMask;
+    public long restoreUnitChangedMask;
     public final BlendState vanillaBlendBefore = new BlendState();
     public final BlendState vanillaBlendAfter = new BlendState();
     public boolean vanillaBlendEnabledBefore;
     public int drawFramebuffer = 0;
     public int readFramebuffer = 0;
     public int texGenGeneration;
+    public int defaultVAO;
+    public final VAOManager vaos = new VAOManager();
+    public final StreamingVaos streamingVaos = new StreamingVaos();
+    public int fontVao;
+    public boolean lockBindCallback;
+    public int foreignDrawDepth;
+    public int internalGlDepth;
+    public int internalDrawDepth;
+    public int savedFilterTextureId;
+    public boolean wideLineEmulationActive = false;
+    public boolean lineStippleActive = false;
+    public Instancing ffpInstancing = Instancing.NONE;
+    public float lastBrightnessX;
+    public float lastBrightnessY;
+    public final Matrix4f multMatrix = new Matrix4f();
+    public final Matrix4d conversionMatrix4d = new Matrix4d();
+    public final Matrix4f conversionMatrix4f = new Matrix4f();
+    public final Matrix4f gluMatrix = new Matrix4f();
+    public final Matrix4f gluMatrix2 = new Matrix4f();
+    public final Vector4f gluVec4 = new Vector4f();
+    public final FloatBuffer gluBuffer = BufferUtils.createFloatBuffer(16);
+    public final float[] texGenTempPlane = new float[4];
+    public final IntBuffer shaderBuf = BufferUtils.createIntBuffer(8);
+    public final FloatBuffer projectionMatrixBuffer = BufferUtils.createFloatBuffer(16);
+    public final ShaderManager ffp = new ShaderManager();
 
     GLContextState() {
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) modifiedAtDepth[i] = new ArrayList<>();
+        allStacksBuilder.addAll(textures.idStacks());
         for (int i = 0; i < lightStates.length; i++) {
             lightStates[i] = track(new BooleanStateStack(GL11.GL_LIGHT0 + i, false, true));
         }
         for (int i = 0; i < GLStateManager.MAX_CLIP_PLANES; i++) {
-            clipPlaneStates[i] = track(new BooleanStateStack(GL11.GL_CLIP_PLANE0 + i));
+            clipPlaneStates[i] = track(new ClipPlaneBooleanState(this, i, GL11.GL_CLIP_PLANE0 + i));
         }
     }
 
     void init() {
         for (int i = 0; i < lightDataStates.length; i++) {
-            lightDataStates[i] = new LightStateStack(GL11.GL_LIGHT0 + i);
+            lightDataStates[i] = member(new LightStateStack(GL11.GL_LIGHT0 + i, StackIdAllocator.nextId()));
         }
+        allStacksBuilder.add(ffp.normalStack);
+        allStacksBuilder.add(ffp.texCoordStack);
+        allStacks = allStacksBuilder.toArray(new IStateStack<?>[0]);
+
+        final int capacity = StackIdAllocator.allocated();
+        stackById = new CowStateStack<?>[capacity];
+        depthsById = new CowDepths[capacity];
+        restoreBitById = new int[capacity];
+        restoreUnitById = new int[capacity];
+        kindById = new byte[capacity];
+        for (final IStateStack<?> stack : allStacks) {
+            final CowStateStack<?> s = (CowStateStack<?>) stack;
+            final int id = s.stackId();
+            stackById[id] = s;
+            depthsById[id] = s.cowDepths();
+            depthsById[id].owner = this;
+            restoreBitById[id] = s.restoreBit();
+            restoreUnitById[id] = s.restoreUnit();
+            kindById[id] = CowDispatch.kindOf(s);
+        }
+
+        modifiedIds = new int[GLStateManager.MAX_ATTRIB_STACK_DEPTH][allStacks.length];
+        modifiedCount = new int[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
     }
 }

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

@@ -19,6 +19,7 @@ import org.lwjgl.opengl.GL43;
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
+import java.util.Arrays;
 
 public final class GLDebug {
 
@@ -586,6 +587,13 @@ public final class GLDebug {
         }
     }
 
+    public static void resetGroupStack() {
+        if (debugState instanceof KHRDebugState khr) {
+            khr.depth = 0;
+            Arrays.fill(khr.groupStack, null);
+        }
+    }
+
     public static void debugMessage(String message) {
         if (debugState != null && Thread.currentThread() == GLStateManager.getMainThread()) {
             debugState.debugMessage(message);

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

@@ -0,0 +1,12 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import org.lwjgl.opengl.OpenGLException;
+
+final class GLErrorReporter {
+
+    private GLErrorReporter() {}
+
+    static void reportError(int error) {
+        throw new OpenGLException(error);
+    }
+}

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

@@ -82,17 +82,17 @@ public final class QuadConverter {
      * @param first       first vertex index (must be aligned to quad boundary, i.e. multiple of 4)
      * @param vertexCount number of vertices (must be multiple of 4)
      */
-    public static void drawQuadsAsTriangles(int first, int vertexCount) {
-        drawSharedQuadEbo(first, vertexCount, 1, false);
+    public static void drawQuadsAsTriangles(GLContextState glCtx, int first, int vertexCount) {
+        drawSharedQuadEbo(glCtx, first, vertexCount, 1, false);
     }
 
-    public static void drawQuadsAsTrianglesInstanced(int first, int vertexCount, int primcount) {
-        drawSharedQuadEbo(first, vertexCount, primcount, true);
+    public static void drawQuadsAsTrianglesInstanced(GLContextState glCtx, int first, int vertexCount, int primcount) {
+        drawSharedQuadEbo(glCtx, first, vertexCount, primcount, true);
     }
 
     private static int misalignedDraws;
 
-    private static void drawSharedQuadEbo(int first, int vertexCount, int primcount, boolean instanced) {
+    private static void drawSharedQuadEbo(GLContextState glCtx, int first, int vertexCount, int primcount, boolean instanced) {
         final int quadCount = vertexCount / 4;
         if ((first & 3) != 0) {
             misalignedDraws++;
@@ -111,26 +111,21 @@ public final class QuadConverter {
                 memPutInt(ptr + 20, base + 3);
                 ptr += 24;
             }
-            uploadAndDraw(dst, quadCount * 6, GL11.GL_UNSIGNED_INT, 4, primcount, instanced);
+            uploadAndDraw(glCtx, dst, quadCount * 6, GL11.GL_UNSIGNED_INT, 4, primcount, instanced);
             return;
         }
-        final boolean locked = GLStateManager.acquireDrawLock();
-        try {
-            GLStateManager.preDraw();
-            final int prevEbo = GLStateManager.getBoundEBO();
-            ensureCapacity(first / 4 + quadCount);
-            RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, eboId);
-            // Index offset: first vertex / 4 quads * 6 indices * 4 bytes per int
-            final long indexOffset = (long) (first / 4) * 6 * 4;
-            if (instanced) {
-                RENDER_BACKEND.drawElementsInstanced(GL11.GL_TRIANGLES, quadCount * 6, INDEX_TYPE, indexOffset, primcount);
-            } else {
-                RENDER_BACKEND.drawElements(GL11.GL_TRIANGLES, quadCount * 6, INDEX_TYPE, indexOffset);
-            }
-            RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEbo);
-        } finally {
-            if (locked) GLStateManager.releaseDrawLock();
+        GLStateManager.preDraw(glCtx, GL11.GL_TRIANGLES);
+        final int prevEbo = glCtx.vaos.boundEBO;
+        ensureCapacity(first / 4 + quadCount);
+        RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, eboId);
+        // Index offset: first vertex / 4 quads * 6 indices * 4 bytes per int
+        final long indexOffset = (long) (first / 4) * 6 * 4;
+        if (instanced) {
+            RENDER_BACKEND.drawElementsInstanced(GL11.GL_TRIANGLES, quadCount * 6, INDEX_TYPE, indexOffset, primcount);
+        } else {
+            RENDER_BACKEND.drawElements(GL11.GL_TRIANGLES, quadCount * 6, INDEX_TYPE, indexOffset);
         }
+        RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEbo);
     }
 
     /**
@@ -143,42 +138,37 @@ public final class QuadConverter {
      * @param indexType       GL_UNSIGNED_INT or GL_UNSIGNED_SHORT
      * @param bytesPerIndex  bytes per index element
      */
-    private static void uploadAndDraw(ByteBuffer dst, int triIndexCount, int indexType, int bytesPerIndex) {
-        uploadAndDraw(dst, triIndexCount, indexType, bytesPerIndex, 1, false);
+    private static void uploadAndDraw(GLContextState glCtx, ByteBuffer dst, int triIndexCount, int indexType, int bytesPerIndex) {
+        uploadAndDraw(glCtx, dst, triIndexCount, indexType, bytesPerIndex, 1, false);
     }
 
-    private static void uploadAndDraw(ByteBuffer dst, int triIndexCount, int indexType, int bytesPerIndex, int primcount, boolean instanced) {
-        final boolean locked = GLStateManager.acquireDrawLock();
-        try {
-            GLStateManager.preDraw();
-            final int needed = triIndexCount * bytesPerIndex;
-            final int prevEbo = GLStateManager.getBoundEBO();
+    private static void uploadAndDraw(GLContextState glCtx, ByteBuffer dst, int triIndexCount, int indexType, int bytesPerIndex, int primcount, boolean instanced) {
+        GLStateManager.preDraw(glCtx, GL11.GL_TRIANGLES);
+        final int needed = triIndexCount * bytesPerIndex;
+        final int prevEbo = glCtx.vaos.boundEBO;
 
-            if (scratchEboId == 0) {
-                scratchEboId = RENDER_BACKEND.genBuffers();
-            }
-
-            RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, scratchEboId);
-
-            if (needed > scratchEboCapacity) {
-                // Power-of-2 growth -- allocate full capacity, upload actual data
-                int newCap = Math.max(4096, scratchEboCapacity);
-                while (newCap < needed) newCap *= 2;
-                RENDER_BACKEND.bufferData(GL15.GL_ELEMENT_ARRAY_BUFFER, newCap, GL15.GL_STREAM_DRAW);
-                scratchEboCapacity = newCap;
-            }
-            RENDER_BACKEND.bufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, 0, dst);
-
-            if (instanced) {
-                RENDER_BACKEND.drawElementsInstanced(GL11.GL_TRIANGLES, triIndexCount, indexType, 0L, primcount);
-            } else {
-                RENDER_BACKEND.drawElements(GL11.GL_TRIANGLES, triIndexCount, indexType, 0L);
-            }
-
-            RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEbo);
-        } finally {
-            if (locked) GLStateManager.releaseDrawLock();
+        if (scratchEboId == 0) {
+            scratchEboId = RENDER_BACKEND.genBuffers();
         }
+
+        RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, scratchEboId);
+
+        if (needed > scratchEboCapacity) {
+            // Power-of-2 growth -- allocate full capacity, upload actual data
+            int newCap = Math.max(4096, scratchEboCapacity);
+            while (newCap < needed) newCap *= 2;
+            RENDER_BACKEND.bufferData(GL15.GL_ELEMENT_ARRAY_BUFFER, newCap, GL15.GL_STREAM_DRAW);
+            scratchEboCapacity = newCap;
+        }
+        RENDER_BACKEND.bufferSubData(GL15.GL_ELEMENT_ARRAY_BUFFER, 0, dst);
+
+        if (instanced) {
+            RENDER_BACKEND.drawElementsInstanced(GL11.GL_TRIANGLES, triIndexCount, indexType, 0L, primcount);
+        } else {
+            RENDER_BACKEND.drawElements(GL11.GL_TRIANGLES, triIndexCount, indexType, 0L);
+        }
+
+        RENDER_BACKEND.bindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, prevEbo);
         memFree(dst);
     }
 
@@ -190,15 +180,15 @@ public final class QuadConverter {
      * @param type       GL_UNSIGNED_INT, GL_UNSIGNED_SHORT, or GL_UNSIGNED_BYTE
      * @param offset     byte offset into the currently bound EBO
      */
-    public static void drawQuadElementsAsTriangles(int indexCount, int type, long offset) {
-        drawQuadElementsFromEbo(indexCount, type, offset, 1, false);
+    public static void drawQuadElementsAsTriangles(GLContextState glCtx, int indexCount, int type, long offset) {
+        drawQuadElementsFromEbo(glCtx, indexCount, type, offset, 1, false);
     }
 
-    public static void drawQuadElementsAsTrianglesInstanced(int indexCount, int type, long offset, int primcount) {
-        drawQuadElementsFromEbo(indexCount, type, offset, primcount, true);
+    public static void drawQuadElementsAsTrianglesInstanced(GLContextState glCtx, int indexCount, int type, long offset, int primcount) {
+        drawQuadElementsFromEbo(glCtx, indexCount, type, offset, primcount, true);
     }
 
-    private static void drawQuadElementsFromEbo(int indexCount, int type, long offset, int primcount, boolean instanced) {
+    private static void drawQuadElementsFromEbo(GLContextState glCtx, int indexCount, int type, long offset, int primcount, boolean instanced) {
         if (indexCount == 0) return;
         assert indexCount % 4 == 0 : "QuadConverter: indexCount must be multiple of 4";
         final int quadCount = indexCount / 4;
@@ -213,13 +203,13 @@ public final class QuadConverter {
         triangulateQuads(memAddress0(src), type, memAddress0(dst), GL11.GL_UNSIGNED_INT, quadCount);
 
         memFree(src);
-        uploadAndDraw(dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4, primcount, instanced);
+        uploadAndDraw(glCtx, dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4, primcount, instanced);
     }
 
     /**
      * Convert a client-side IntBuffer of quad indices to triangles.
      */
-    public static void drawQuadElementsAsTriangles(IntBuffer indices) {
+    public static void drawQuadElementsAsTriangles(GLContextState glCtx, IntBuffer indices) {
         final int indexCount = indices.remaining();
         if (indexCount == 0) return;
         assert indexCount % 4 == 0;
@@ -230,13 +220,13 @@ public final class QuadConverter {
         final long srcAddr = memAddress0(indices) + (long) indices.position() * 4;
         triangulateQuads(srcAddr, GL11.GL_UNSIGNED_INT, memAddress0(dst), GL11.GL_UNSIGNED_INT, quadCount);
 
-        uploadAndDraw(dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4);
+        uploadAndDraw(glCtx, dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4);
     }
 
     /**
      * Convert a client-side ShortBuffer of quad indices to triangles.
      */
-    public static void drawQuadElementsAsTriangles(ShortBuffer indices) {
+    public static void drawQuadElementsAsTriangles(GLContextState glCtx, ShortBuffer indices) {
         final int indexCount = indices.remaining();
         if (indexCount == 0) return;
         assert indexCount % 4 == 0;
@@ -247,13 +237,13 @@ public final class QuadConverter {
         final long srcAddr = memAddress0(indices) + (long) indices.position() * 2;
         triangulateQuads(srcAddr, GL11.GL_UNSIGNED_SHORT, memAddress0(dst), GL11.GL_UNSIGNED_SHORT, quadCount);
 
-        uploadAndDraw(dst, triIndexCount, GL11.GL_UNSIGNED_SHORT, 2);
+        uploadAndDraw(glCtx, 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) {
+    public static void drawQuadElementsAsTriangles(GLContextState glCtx, int count, int type, ByteBuffer indices) {
         if (count == 0) return;
         assert count % 4 == 0;
         final int quadCount = count / 4;
@@ -263,23 +253,7 @@ public final class QuadConverter {
         final ByteBuffer dst = memAlloc(triIndexCount * 4);
         triangulateQuads(srcAddr, type, memAddress0(dst), GL11.GL_UNSIGNED_INT, quadCount);
 
-        uploadAndDraw(dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4);
-    }
-
-    /**
-     * Clean up the shared EBO.
-     */
-    public static void destroy() {
-        if (eboId != 0) {
-            GLStateManager.glDeleteBuffers(eboId);
-            eboId = 0;
-            maxQuads = 0;
-        }
-        if (scratchEboId != 0) {
-            GLStateManager.glDeleteBuffers(scratchEboId);
-            scratchEboId = 0;
-            scratchEboCapacity = 0;
-        }
+        uploadAndDraw(glCtx, dst, triIndexCount, GL11.GL_UNSIGNED_INT, 4);
     }
 
     /**

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

@@ -169,13 +169,13 @@ public class RenderSystem {
 
         if (isGLES) {
             GLStateManager.LOGGER.info("GL ES context detected, enabling shader transformer.");
-            ShaderManager.getInstance().enable();
+            ShaderManager.enable();
         } else if (GLStateManager.capabilities.OpenGL32) {
             final int profileMask = RENDER_BACKEND.getInteger(GL32.GL_CONTEXT_PROFILE_MASK);
             if ((profileMask & GL32.GL_CONTEXT_CORE_PROFILE_BIT) != 0) {
                 coreProfile = true;
                 GLStateManager.LOGGER.info("GL 3.3 core profile detected, enabling FFP shader emulation.");
-                ShaderManager.getInstance().enable();
+                ShaderManager.enable();
             } else {
                 throw new IllegalStateException("Non-core GL context (profile mask 0x" + Integer.toHexString(profileMask)
                     + "); FFP emulation requires a core profile and nothing would render. Context creation should have rejected this.");
@@ -503,13 +503,12 @@ public class RenderSystem {
         dsaState.bindTextureToUnit(target, unit, texture);
     }
 
-    public static final FloatBuffer PROJECTION_MATRIX_BUFFER = BufferUtils.createFloatBuffer(16);
-
     public static void setupProjectionMatrix(Matrix4f matrix) {
+        final FloatBuffer projectionMatrixBuffer = GLStateManager.ctx().projectionMatrixBuffer;
         GLStateManager.glMatrixMode(GL11.GL_PROJECTION);
         GLStateManager.glPushMatrix();
-        matrix.get(0, PROJECTION_MATRIX_BUFFER);
-        GLStateManager.glLoadMatrix(PROJECTION_MATRIX_BUFFER);
+        matrix.get(0, projectionMatrixBuffer);
+        GLStateManager.glLoadMatrix(projectionMatrixBuffer);
         GLStateManager.glMatrixMode(GL11.GL_MODELVIEW);
     }
 
@@ -637,6 +636,11 @@ public class RenderSystem {
         GLStateManager.glSamplerParameteri(sampler, pname, param);
     }
 
+    public static void samplerParameterf(int sampler, int pname, float param) {
+        if (!supportsSamplerObjects || sampler == 0) return;
+        GLStateManager.glSamplerParameterf(sampler, pname, param);
+    }
+
     public static void bindSamplerToUnit(int unit, int sampler) {
         if (!supportsSamplerObjects) return;
         GLStateManager.glBindSampler(unit, sampler);

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

@@ -0,0 +1,239 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.recording.commands.DisplayListCommand;
+import com.gtnewhorizons.angelica.glsm.stacks.CowStateStack;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import org.lwjgl.opengl.GL11;
+
+public final class StateSet {
+
+    public static final int R_DEPTH = 1;
+    public static final int R_BLEND = 1 << 1;
+    public static final int R_COLOR_MASK = 1 << 2;
+    public static final int R_CLEAR_COLOR = 1 << 3;
+    public static final int R_DRAW_BUFFER = 1 << 4;
+    public static final int R_LOGIC_OP = 1 << 5;
+    public static final int R_SECONDARY_COLOR = 1 << 6;
+    public static final int R_STENCIL = 1 << 7;
+    public static final int R_VIEWPORT = 1 << 8;
+    public static final int R_LINE = 1 << 9;
+    public static final int R_POINT = 1 << 10;
+    public static final int R_POLYGON = 1 << 11;
+    public static final int R_TEXTURE = 1 << 12;
+    public static final int R_ACTIVE_UNIT = 1 << 13;
+    public static final int R_PROGRAM = 1 << 14;
+    public static final int R_SCISSOR = 1 << 15;
+
+    public static final int B_FRAG_COLORBUF = 1;
+    public static final int B_FRAG_TEXTURE = 1 << 1;
+    public static final int B_FRAG_FOG = 1 << 2;
+    public static final int B_CURRENT = 1 << 3;
+    public static final int B_LIGHTING = 1 << 4;
+    public static final int B_TRANSFORM = 1 << 5;
+
+    private static final long[] NO_MEMBERS = new long[0];
+    private static final Int2ObjectMap<StateSet> maskToStateSetMap = new Int2ObjectOpenHashMap<>();
+
+    public final int glMask;
+    public final long[] members;
+    public final int restore;
+    public final int bump;
+    public final boolean blendSnapshot;
+    public final DisplayListCommand pushCommand;
+
+    StateSet(int glMask, long[] members, int restore, int bump, boolean blendSnapshot) {
+        this.glMask = glMask;
+        this.members = members;
+        this.restore = restore;
+        this.bump = bump;
+        this.blendSnapshot = blendSnapshot;
+        this.pushCommand = () -> GLStateManager.pushStateLive(this);
+    }
+
+    public boolean contains(int id) {
+        if (id < 0) return false;
+        final int word = id >> 6;
+        return word < members.length && (members[word] & (1L << id)) != 0;
+    }
+
+    private static long[] ids(CowStateStack<?>... stacks) {
+        if (stacks.length == 0) return NO_MEMBERS;
+        int max = 0;
+        for (CowStateStack<?> s : stacks) max = Math.max(max, s.stackId());
+        final long[] bits = new long[(max >> 6) + 1];
+        for (CowStateStack<?> s : stacks) {
+            final int id = s.stackId();
+            bits[id >> 6] |= 1L << id;
+        }
+        return bits;
+    }
+
+    public static final StateSet BATCH = buildBatch();
+    public static final StateSet FONT = buildFont();
+    public static final StateSet FONT_PIPELINE = buildFontPipeline();
+    public static final StateSet HAND = buildHand();
+    public static final StateSet BLEND = buildBlend();
+    public static final StateSet ALPHA = buildAlpha();
+    public static final StateSet CUTOUT = buildCutout();
+    public static final StateSet MASKS = buildMasks();
+    public static final StateSet CULL = buildCull();
+
+    private static StateSet buildBatch() {
+        return new StateSet(0,
+            ids(
+                GLStateManager.getBlendState(), GLStateManager.getAlphaState(), GLStateManager.getDepthState(),
+                GLStateManager.getColorMask(), GLStateManager.getPolygonState(),
+                GLStateManager.getTextures().getTextureUnitBindings(0), GLStateManager.getTextures().getTextureUnitBindings(1),
+                GLStateManager.getActiveTextureUnitStack(),
+                GLStateManager.getBlendMode(), GLStateManager.getAlphaTest(), GLStateManager.getDepthTest(),
+                GLStateManager.getLightingState(), GLStateManager.getCullState(), GLStateManager.getPolygonOffsetFillState(),
+                GLStateManager.getTextures().getTextureUnitStates(0)
+            ),
+            R_BLEND | R_DEPTH | R_COLOR_MASK | R_POLYGON | R_TEXTURE | R_ACTIVE_UNIT,
+            B_FRAG_COLORBUF,
+            true);
+    }
+
+    private static StateSet buildFont() {
+        return new StateSet(0,
+            ids(
+                GLStateManager.getBlendState(), GLStateManager.getDepthState(), GLStateManager.getShadeModelState(),
+                GLStateManager.getTextures().getTextureUnitBindings(0), GLStateManager.getTextures().getTextureUnitBindings(1),
+                GLStateManager.getActiveTextureUnitStack(), GLStateManager.getProgramStack(),
+                GLStateManager.getBlendMode(), GLStateManager.getAlphaTest(), GLStateManager.getDepthTest(),
+                GLStateManager.getTextures().getTextureUnitStates(0)
+            ),
+            R_BLEND | R_DEPTH | R_TEXTURE | R_ACTIVE_UNIT | R_PROGRAM,
+            0,
+            true);
+    }
+
+    private static StateSet buildFontPipeline() {
+        return new StateSet(0,
+            ids(
+                GLStateManager.getBlendState(), GLStateManager.getDepthState(),
+                GLStateManager.getTextures().getTextureUnitBindings(0), GLStateManager.getTextures().getTextureUnitBindings(1),
+                GLStateManager.getActiveTextureUnitStack(),
+                GLStateManager.getBlendMode(), GLStateManager.getAlphaTest(), GLStateManager.getDepthTest(),
+                GLStateManager.getTextures().getTextureUnitStates(0)
+            ),
+            R_BLEND | R_DEPTH | R_TEXTURE | R_ACTIVE_UNIT,
+            0,
+            true);
+    }
+
+    private static StateSet buildHand() {
+        return new StateSet(0,
+            ids(
+                GLStateManager.getBlendState(), GLStateManager.getAlphaState(), GLStateManager.getDepthState(),
+                GLStateManager.getBlendMode(), GLStateManager.getAlphaTest(), GLStateManager.getTextures().getTextureUnitStates(1)
+            ),
+            R_BLEND | R_DEPTH,
+            B_FRAG_COLORBUF,
+            true);
+    }
+
+    private static StateSet buildBlend() {
+        return new StateSet(0,
+            ids(GLStateManager.getBlendState(), GLStateManager.getBlendMode()),
+            R_BLEND,
+            0,
+            true);
+    }
+
+    private static StateSet buildAlpha() {
+        return new StateSet(0,
+            ids(GLStateManager.getAlphaState(), GLStateManager.getAlphaTest()),
+            0,
+            B_FRAG_COLORBUF,
+            false);
+    }
+
+    private static StateSet buildCutout() {
+        return new StateSet(0,
+            ids(GLStateManager.getAlphaState(), GLStateManager.getAlphaTest(), GLStateManager.getTextures().getTextureUnitStates(1)),
+            0,
+            B_FRAG_COLORBUF,
+            false);
+    }
+
+    private static StateSet buildMasks() {
+        return new StateSet(0,
+            ids(GLStateManager.getDepthState(), GLStateManager.getColorMask()),
+            R_DEPTH | R_COLOR_MASK,
+            0,
+            false);
+    }
+
+    private static StateSet buildCull() {
+        return new StateSet(0,
+            ids(GLStateManager.getPolygonState(), GLStateManager.getCullState()),
+            R_POLYGON,
+            0,
+            false);
+    }
+
+    public static StateSet forMask(int mask) {
+        StateSet cached = maskToStateSetMap.get(mask);
+        if (cached != null) {
+            return cached;
+        }
+        cached = buildForMask(mask);
+        maskToStateSetMap.put(mask, cached);
+        return cached;
+    }
+
+    private static StateSet buildForMask(int mask) {
+        int restore = 0;
+        int bump = 0;
+        final boolean blendSnapshot = (mask & (GL11.GL_COLOR_BUFFER_BIT | GL11.GL_ENABLE_BIT)) != 0;
+
+        if ((mask & GL11.GL_DEPTH_BUFFER_BIT) != 0) {
+            restore |= R_DEPTH;
+        }
+        if ((mask & GL11.GL_COLOR_BUFFER_BIT) != 0) {
+            restore |= R_BLEND | R_COLOR_MASK | R_CLEAR_COLOR | R_DRAW_BUFFER | R_LOGIC_OP;
+            bump |= B_FRAG_COLORBUF;
+        }
+        if ((mask & GL11.GL_CURRENT_BIT) != 0) {
+            restore |= R_SECONDARY_COLOR;
+            bump |= B_CURRENT;
+        }
+        if ((mask & GL11.GL_STENCIL_BUFFER_BIT) != 0) {
+            restore |= R_STENCIL;
+        }
+        if ((mask & GL11.GL_VIEWPORT_BIT) != 0) {
+            restore |= R_VIEWPORT;
+        }
+        if ((mask & GL11.GL_SCISSOR_BIT) != 0) {
+            restore |= R_SCISSOR;
+        }
+        if ((mask & GL11.GL_LINE_BIT) != 0) {
+            restore |= R_LINE;
+        }
+        if ((mask & GL11.GL_POINT_BIT) != 0) {
+            restore |= R_POINT;
+        }
+        if ((mask & GL11.GL_POLYGON_BIT) != 0) {
+            restore |= R_POLYGON;
+        }
+        if ((mask & GL11.GL_TEXTURE_BIT) != 0) {
+            restore |= R_TEXTURE | R_ACTIVE_UNIT;
+            bump |= B_FRAG_TEXTURE;
+        }
+        if ((mask & GL11.GL_LIGHTING_BIT) != 0) {
+            bump |= B_LIGHTING;
+        }
+        if ((mask & GL11.GL_FOG_BIT) != 0) {
+            bump |= B_FRAG_FOG;
+        }
+        if ((mask & GL11.GL_TRANSFORM_BIT) != 0) {
+            bump |= B_TRANSFORM;
+        }
+
+        final long[] members = Feature.maskToMembers(mask);
+
+        return new StateSet(mask, members, restore, bump, blendSnapshot);
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/backend/Lwjgl2GLRenderBackend.java

@@ -134,6 +134,12 @@ public final class Lwjgl2GLRenderBackend extends RenderBackend {
         return caps != null && caps.GL_EXT_texture_filter_anisotropic;
     }
 
+    @Override
+    public void updateDisplayFromWorkerThread(boolean processMessages) {
+        if (processMessages) pumpDisplayMessages();
+        Display.update(false);
+    }
+
     @Override
     public void flush() {GL11.glFlush();}
 

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

@@ -3,6 +3,7 @@ package com.gtnewhorizons.angelica.glsm.backend;
 import com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.RenderSystem;
+import org.lwjgl.LWJGLException;
 import org.lwjgl.opengl.Display;
 import org.lwjgl.opengl.GL20;
 
@@ -241,6 +242,8 @@ public abstract class RenderBackend {
         }
     }
 
+    public void invalidateStateMirror() {}
+
     public void onFrameEnd() {}
 
     /** Fired by lwjgl3ify Display before a mutation that recreates the swapchain. */
@@ -251,6 +254,13 @@ public abstract class RenderBackend {
     public boolean handleSwapBuffers() { return false; }
     public void onRenderThreadReleased(Thread thread) {}
 
+    public void updateDisplayFromWorkerThread(boolean processMessages) throws LWJGLException {
+        GLStateManager.swapBuffers();
+        if (processMessages) {
+            pumpDisplayMessages();
+        }
+    }
+
     public String getTransferDebugInfo() { return null; }
 
     public boolean bindVoxelizationRegion(int ssboBinding, long openPass, float x, float y, float z) { return false; }

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

@@ -104,7 +104,9 @@ public class DSAARB extends DSAUnsupported {
             super.bindTextureToUnit(target != 0 ? target : GL11.GL_TEXTURE_2D, unit, texture);
         } else {
             RENDER_BACKEND.bindTextureUnit(unit, texture);
-            GLStateManager.getTextures().getTextureUnitBindings(unit).setBinding(texture, target);
+            final var binding = GLStateManager.getTextures().getTextureUnitBindings(unit);
+            binding.beforeModify();
+            binding.setBinding(texture, target);
             GLStateManager.trackMaxBoundTextureUnit(unit);
         }
     }

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

@@ -0,0 +1,55 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.joml.Matrix4f;
+import org.joml.Matrix4fc;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL14;
+
+public final class CombinedGlint {
+    private static final Matrix4f savedMatrix = new Matrix4f();
+    private static final Matrix4f inverse = new Matrix4f();
+    private static final Matrix4f relative = new Matrix4f();
+    private static boolean active;
+    private static boolean replaceAlpha;
+
+    private CombinedGlint() {}
+
+    public static boolean isActive() {
+        return active;
+    }
+
+    public static boolean replacesAlpha() {
+        return active && replaceAlpha;
+    }
+
+    public static boolean begin(Matrix4fc secondTextureMatrix) {
+        if (active || GLStateManager.getActiveProgram() != 0 || GLStateManager.getLightingState().isEnabled() || GLStateManager.getColorSumState().isEnabled() || !GLStateManager.glIsEnabled(GL11.GL_BLEND)) return false;
+        final var blend = GLStateManager.getBlendState();
+        final boolean lastAlpha = blend.getSrcAlpha() == GL11.GL_ONE && blend.getDstAlpha() == GL11.GL_ZERO && blend.getEquationAlpha() == GL14.GL_FUNC_ADD;
+        final boolean preserveAlpha = blend.getSrcAlpha() == GL11.GL_ZERO && blend.getDstAlpha() == GL11.GL_ONE && (blend.getEquationAlpha() == GL14.GL_FUNC_ADD || blend.getEquationAlpha() == GL14.GL_FUNC_REVERSE_SUBTRACT);
+        if (blend.getSrcRgb() != GL11.GL_SRC_COLOR || blend.getDstRgb() != GL11.GL_ONE
+            || (!lastAlpha && !preserveAlpha && (blend.getSrcAlpha() != GL11.GL_SRC_COLOR || blend.getDstAlpha() != GL11.GL_ONE || blend.getEquationAlpha() != blend.getEquationRgb()))
+            || (blend.getEquationRgb() != GL14.GL_FUNC_ADD && blend.getEquationRgb() != GL14.GL_FUNC_REVERSE_SUBTRACT)) return false;
+        final var textures = GLStateManager.getTextures();
+        if (!textures.getTextureUnitStates(0).isEnabled() || textures.getTextureUnitBindings(0).getBinding() == 0 || textures.getTexEnvState(0).mode != GL11.GL_MODULATE) return false;
+        if (textures.getTextureUnitStates(1).isEnabled() && textures.getTextureUnitBindings(1).getBinding() != 0 && textures.getTexEnvState(1).mode != GL11.GL_MODULATE) return false;
+        for (int unit = 2; unit < 4; unit++) {
+            if (textures.getTextureUnitStates(unit).isEnabled() && textures.getTextureUnitBindings(unit).getBinding() != 0) return false;
+        }
+        inverse.set(textures.getTextureUnitMatrix(0)).invert();
+        relative.set(secondTextureMatrix).mul(inverse);
+        if (!relative.isFinite()) return false;
+        savedMatrix.set(textures.getTextureUnitMatrix(3));
+        GLStateManager.setTextureMatrix(3, relative);
+        replaceAlpha = lastAlpha;
+        active = true;
+        return true;
+    }
+
+    public static void end() {
+        if (!active) return;
+        active = false;
+        GLStateManager.setTextureMatrix(3, savedMatrix);
+    }
+}

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

@@ -0,0 +1,27 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.lwjgl.opengl.GL11;
+
+public final class CubeInstancedAttribs {
+
+    public static final int LOC_LIGHTMAP_SCALE = InstancedAttribs.LOC_LIGHTMAP;
+    public static final int LOC_CUBE_TEX = 15;
+
+    public static final int OFFSET_LIGHTMAP_SCALE = InstancedAttribs.HEAD_SIZE;
+    public static final int OFFSET_CUBE_TEX = OFFSET_LIGHTMAP_SCALE + 16;
+    public static final int STRIDE = OFFSET_CUBE_TEX + 16;
+
+    public static void pointInstanceAttribs(long base) {
+        InstancedAttribs.pointHead(base, STRIDE);
+        GLStateManager.glVertexAttribPointer(LOC_LIGHTMAP_SCALE, 4, GL11.GL_FLOAT, false, STRIDE, base + OFFSET_LIGHTMAP_SCALE);
+        GLStateManager.glVertexAttribPointer(LOC_CUBE_TEX, 4, GL11.GL_FLOAT, false, STRIDE, base + OFFSET_CUBE_TEX);
+    }
+
+    static void enableInstanceArrays() {
+        InstancedAttribs.enableHeadArrays();
+        InstancedAttribs.enableInstanced(LOC_CUBE_TEX);
+    }
+
+    private CubeInstancedAttribs() {}
+}

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

@@ -0,0 +1,54 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutFloat;
+
+public record CubeParams(float minX, float minY, float minZ, float spanX, float spanY, float spanZ, float u0, float v0, float uScaleX, float vScaleY, float uScaleZ, float vScaleZ) {
+
+    private static final float MIN_SPAN = 1.0e-4f;
+
+    public CubeParams {
+        if (!(spanX > MIN_SPAN && spanY > MIN_SPAN && spanZ > MIN_SPAN)) throw new IllegalArgumentException("degenerate cube span");
+    }
+
+    public static CubeParams of(float texWidth, float texHeight, boolean mirror, int texU, int texV, float x, float y, float z, int sizeX, int sizeY, int sizeZ, float inflate) {
+        if (texWidth <= 0.0f || texHeight <= 0.0f) return null;
+        if (sizeX < 0 || sizeY < 0 || sizeZ < 0) return null;
+        if (mirror && sizeX == 0) return null;
+        final float minX = x - inflate;
+        final float minY = y - inflate;
+        final float minZ = z - inflate;
+        final float spanX = ((x + sizeX) + inflate) - minX;
+        final float spanY = ((y + sizeY) + inflate) - minY;
+        final float spanZ = ((z + sizeZ) + inflate) - minZ;
+        if (spanX <= MIN_SPAN || spanY <= MIN_SPAN || spanZ <= MIN_SPAN) return null;
+        return new CubeParams(minX, minY, minZ, spanX, spanY, spanZ, texU / texWidth, texV / texHeight, (mirror ? -sizeX : sizeX) / texWidth, sizeY / texHeight, sizeZ / texWidth, sizeZ / texHeight);
+    }
+
+    public void writeRows(long ptr, float[] mv, int off, float scale) {
+        final float tx = minX * scale;
+        final float ty = minY * scale;
+        final float tz = minZ * scale;
+        final float sx = spanX * scale;
+        final float sy = spanY * scale;
+        final float sz = spanZ * scale;
+        for (int r = 0; r < 3; r++) {
+            final float c0 = mv[off + r];
+            final float c1 = mv[off + 4 + r];
+            final float c2 = mv[off + 8 + r];
+            final long row = ptr + InstancedAttribs.OFFSET_ROWS + r * 16L;
+            memPutFloat(row, c0 * sx);
+            memPutFloat(row + 4, c1 * sy);
+            memPutFloat(row + 8, c2 * sz);
+            memPutFloat(row + 12, mv[off + 12 + r] + c0 * tx + c1 * ty + c2 * tz);
+        }
+    }
+
+    public void writeTexture(long ptr) {
+        memPutFloat(ptr + CubeInstancedAttribs.OFFSET_LIGHTMAP_SCALE + 8, uScaleZ);
+        memPutFloat(ptr + CubeInstancedAttribs.OFFSET_LIGHTMAP_SCALE + 12, vScaleZ);
+        memPutFloat(ptr + CubeInstancedAttribs.OFFSET_CUBE_TEX, u0);
+        memPutFloat(ptr + CubeInstancedAttribs.OFFSET_CUBE_TEX + 4, v0);
+        memPutFloat(ptr + CubeInstancedAttribs.OFFSET_CUBE_TEX + 8, uScaleX);
+        memPutFloat(ptr + CubeInstancedAttribs.OFFSET_CUBE_TEX + 12, vScaleY);
+    }
+}

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

@@ -107,6 +107,12 @@ public final class FFPUniformBlock {
     public static final int FOG_PARAMS = vec4("u_FogParams");
     public static final int FOG_COLOR = vec4("u_FogColor");
 
+    // Rain and snow, for Instancing.WEATHER. 0 = (translate.xyz, 1/radius),
+    // 1 = (cameraFrac.xy, partialTicks, age), 2 = (rainScroll, snowScroll, rainStrength, unused).
+    public static final int WEATHER_PARAMS_0 = vec4("u_WeatherParams0");
+    public static final int WEATHER_PARAMS_1 = vec4("u_WeatherParams1");
+    public static final int WEATHER_PARAMS_2 = vec4("u_WeatherParams2");
+
     public static final int SIZE;
     public static final String GLSL_DECL;
 

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

@@ -2,6 +2,7 @@ package com.gtnewhorizons.angelica.glsm.ffp;
 
 import com.gtnewhorizon.gtnhlib.client.renderer.cel.api.util.NormI8;
 import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement.Usage;
+import com.gtnewhorizons.angelica.glsm.GLContextState;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.hooks.GLSMHooks;
 import com.gtnewhorizons.angelica.glsm.hooks.ImmediateExtendedAttribHandler;
@@ -59,7 +60,6 @@ public final class FfpExtendedAttribs {
 
     private static final HashMap<Key, ExtBuffer> cache = new HashMap<>();
     private static final Key lookup = new Key();
-    private static int internalGlDepth = 0;
 
     private static final HashMap<EboKey, Boolean> eboPatternCache = new HashMap<>();
     private static final EboKey eboLookup = new EboKey();
@@ -79,15 +79,19 @@ public final class FfpExtendedAttribs {
         return cache.isEmpty() && eboPatternCache.isEmpty();
     }
 
-    private static int internalDrawDepth = 0;
+    public static void beginInternalDraw() { GLStateManager.ctx().internalDrawDepth++; }
 
-    public static void beginInternalDraw() { internalDrawDepth++; }
+    public static void endInternalDraw() {
+        final GLContextState glCtx = GLStateManager.ctx();
+        if (glCtx.internalDrawDepth > 0) glCtx.internalDrawDepth--;
+    }
 
-    public static void endInternalDraw() { if (internalDrawDepth > 0) internalDrawDepth--; }
+    private static void beginInternalGl() { GLStateManager.ctx().internalGlDepth++; }
 
-    private static void beginInternalGl() { internalGlDepth++; }
-
-    private static void endInternalGl() { if (internalGlDepth > 0) internalGlDepth--; }
+    private static void endInternalGl() {
+        final GLContextState glCtx = GLStateManager.ctx();
+        if (glCtx.internalGlDepth > 0) glCtx.internalGlDepth--;
+    }
 
     private static boolean isNotConventionalTexturedArray(VAOManager.Attrib a) {
         return a == null || !a.enabled || a.genericPointer || a.vboId == 0 || a.size < 2;
@@ -104,20 +108,20 @@ public final class FfpExtendedAttribs {
         return true;
     }
 
-    public static boolean maybeBind(int mode, int first, int count) {
+    public static boolean maybeBind(GLContextState glCtx, int mode, int first, int count) {
         final ImmediateExtendedAttribHandler h = GLSMHooks.immediateExtendedHandler;
         if (h == null) return false;
-        if (internalDrawDepth > 0) return false;
+        if (glCtx.internalDrawDepth > 0) return false;
         final int extPrim = ImmediateExtendedAttribHandler.extPrimVerts(mode, count);
         if (extPrim == 0 || first < 0) return false;
         if (!h.wantsExtended()) return false;
 
-        final VAOManager.Attrib pos = VAOManager.get(POSITION_LOC);
-        final VAOManager.Attrib uv = VAOManager.get(UV_LOC);
+        final VAOManager.Attrib pos = glCtx.vaos.attrib(POSITION_LOC);
+        final VAOManager.Attrib uv = glCtx.vaos.attrib(UV_LOC);
         if (isNotConventionalTexturedArray(pos) || isNotConventionalTexturedArray(uv)) return false;
         if (isStreaming(pos.vboId) || isStreaming(uv.vboId)) return false;
 
-        VAOManager.Attrib normal = extPrim == 3 ? VAOManager.get(NORMAL_LOC) : null;
+        VAOManager.Attrib normal = extPrim == 3 ? glCtx.vaos.attrib(NORMAL_LOC) : null;
         if (normal != null && (!normal.enabled || normal.genericPointer || normal.vboId == 0 || normal.size < 3
             || isStreaming(normal.vboId))) {
             normal = null;
@@ -126,17 +130,17 @@ public final class FfpExtendedAttribs {
         return bindExt(h, mode, first, count, extPrim, pos, uv, normal);
     }
 
-    public static boolean maybeBindIndexed(int mode, int indexCount, int indexType, long indicesOffset) {
+    public static boolean maybeBindIndexed(GLContextState glCtx, int mode, int indexCount, int indexType, long indicesOffset) {
         final ImmediateExtendedAttribHandler h = GLSMHooks.immediateExtendedHandler;
         if (h == null) return false;
-        if (internalDrawDepth > 0) return false;
+        if (glCtx.internalDrawDepth > 0) return false;
         if (mode != GL11.GL_TRIANGLES || indexCount <= 0 || indexCount % 6 != 0) return false;
         if (!h.wantsExtended()) return false;
 
-        final VAOManager.Attrib pos = VAOManager.get(POSITION_LOC);
-        final VAOManager.Attrib uv = VAOManager.get(UV_LOC);
+        final VAOManager.Attrib pos = glCtx.vaos.attrib(POSITION_LOC);
+        final VAOManager.Attrib uv = glCtx.vaos.attrib(UV_LOC);
         if (isNotConventionalTexturedArray(pos) || isNotConventionalTexturedArray(uv)) return false;
-        if (isStreaming(pos.vboId) || isStreaming(uv.vboId) || isStreaming(VAOManager.boundEBO)) return false;
+        if (isStreaming(pos.vboId) || isStreaming(uv.vboId) || isStreaming(glCtx.vaos.boundEBO)) return false;
 
         final int indexSize = indexTypeBytes(indexType);
         if (indexSize == 0) return false;
@@ -144,7 +148,7 @@ public final class FfpExtendedAttribs {
         final int first = (int) (indicesOffset / indexSize) / 6 * 4;
         final int count = indexCount / 6 * 4;
 
-        if (!isQuadPatternEbo(VAOManager.boundEBO, indicesOffset, indexCount, indexType, indexSize, first)) return false;
+        if (!isQuadPatternEbo(glCtx.vaos.boundEBO, indicesOffset, indexCount, indexType, indexSize, first)) return false;
 
         // Build/bind as GL_QUADS (the real primitive): face-normal tangents, 4-vertex tiles, no per-vertex normal.
         return bindExt(h, GL11.GL_QUADS, first, count, 4, pos, uv, null);
@@ -226,8 +230,8 @@ public final class FfpExtendedAttribs {
         GLStateManager.glVertexAttrib4f(ImmediateExtendedAttribHandler.LOC_TANGENT, 1.0f, 0.0f, 0.0f, 1.0f);
     }
 
-    public static void onDeleteBuffer(int vboId) {
-        if (internalGlDepth > 0 || vboId == 0) return;
+    public static void onDeleteBuffer(GLContextState glCtx, int vboId) {
+        if (glCtx.internalGlDepth > 0 || vboId == 0) return;
         dropDerivedFrom(vboId);
         respecCounts.remove(vboId);
         respecFrames.remove(vboId);
@@ -236,8 +240,8 @@ public final class FfpExtendedAttribs {
         persistentSources.remove(vboId);
     }
 
-    public static void onBufferRespecified(int vboId) {
-        if (internalGlDepth > 0 || vboId == 0) return;
+    public static void onBufferRespecified(GLContextState glCtx, int vboId) {
+        if (glCtx.internalGlDepth > 0 || vboId == 0) return;
         if (streamingSources.contains(vboId)) {
             respecFrames.put(vboId, frame);
             return;
@@ -268,16 +272,15 @@ public final class FfpExtendedAttribs {
         respecFrames.put(vboId, frame);
     }
 
-    public static void markStreaming(int vboId) {
-        if (internalGlDepth > 0 || vboId == 0) return;
+    private static void markStreaming(int vboId) {
         respecCounts.remove(vboId);
         respecRunStart.remove(vboId);
         respecFrames.put(vboId, frame);
         if (streamingSources.add(vboId)) dropDerivedFrom(vboId);
     }
 
-    public static void markPersistent(int vboId) {
-        if (internalGlDepth > 0 || vboId == 0) return;
+    public static void markPersistent(GLContextState glCtx, int vboId) {
+        if (glCtx.internalGlDepth > 0 || vboId == 0) return;
         markStreaming(vboId);
         persistentSources.add(vboId);
     }

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

@@ -2,8 +2,10 @@ package com.gtnewhorizons.angelica.glsm.ffp;
 
 import java.util.Arrays;
 
+import com.gtnewhorizons.angelica.glsm.GLContextState;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.TexEnvState;
+import com.gtnewhorizons.angelica.glsm.states.TextureUnitArray;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL12;
 import org.lwjgl.opengl.GL13;
@@ -12,7 +14,7 @@ import org.lwjgl.opengl.GL13;
  * Packed-long fragment shader permutation key for FFP emulation.
  *
  * Layout:
- *   long[0]: global bits (13) + unit 0 (47 bits at offset 13)
+ *   long[0]: global bits (14) + unit 0 (47 bits at offset 14)
  *   long[1..3]: unit 1..3 (47 bits each, low-aligned)
  * Only max(1, nrEnabledUnits) longs are significant.
  *
@@ -63,7 +65,9 @@ public final class FragmentKey {
     public static final int FOG_EXP    = 2;
     public static final int FOG_EXP2   = 3;
 
-    private static final int GLOBAL_BITS = 13;
+    private static final int GLOBAL_BITS = 14;
+    private static final int BIT_COMBINED_GLINT = 61;
+    private static final int BIT_GLINT_REPLACE_ALPHA = 62;
     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
@@ -72,6 +76,7 @@ public final class FragmentKey {
     private static final int BIT_OVERLAY_ENABLED   = 10; // 1 bit
     private static final int BIT_LINE_STIPPLE      = 11; // 1 bit
     private static final int BIT_COLOR_SUM         = 12; // 1 bit
+    private static final int BIT_OVERLAY_INSTANCED = 13;
 
     private static final int U_ENABLED         = 0;
     private static final int U_MODE            = 1;   // 3 bits
@@ -103,11 +108,17 @@ public final class FragmentKey {
      * @return number of significant longs (1..4)
      */
     public static int packFromState(long[] out) {
+        return packFromState(out, GLStateManager.ctx());
+    }
+
+    public static int packFromState(long[] out, GLContextState glCtx) {
         long global = 0;
+        if (CombinedGlint.isActive()) global |= 1L << BIT_COMBINED_GLINT;
+        if (CombinedGlint.replacesAlpha()) global |= 1L << BIT_GLINT_REPLACE_ALPHA;
 
         // Fog
-        if (GLStateManager.getFogMode().isEnabled()) {
-            final int fogMode = switch (GLStateManager.getFogState().getFogMode()) {
+        if (glCtx.fogMode.isEnabled()) {
+            final int fogMode = switch (glCtx.fogState.getFogMode()) {
                 case GL11.GL_LINEAR -> FOG_LINEAR;
                 case GL11.GL_EXP    -> FOG_EXP;
                 case GL11.GL_EXP2   -> FOG_EXP2;
@@ -117,37 +128,40 @@ public final class FragmentKey {
         }
 
         // Alpha test
-        if (GLStateManager.getAlphaTest().isEnabled()) {
+        if (glCtx.alphaTest.isEnabled()) {
             global |= (1L << BIT_ALPHA_TEST);
-            global |= ((long) (encodeAlphaFunc(GLStateManager.getAlphaState().getFunction()) & 0x7)) << BIT_ALPHA_FUNC;
+            global |= ((long) (encodeAlphaFunc(glCtx.alphaState.getFunction()) & 0x7)) << BIT_ALPHA_FUNC;
         }
 
         // Damage overlay
-        if (GLStateManager.getOverlayA() != 0.0f) {
+        if (glCtx.ffpInstancing.hasInstanceHead()) {
+            global |= (1L << BIT_OVERLAY_INSTANCED);
+        } else if (glCtx.overlayA != 0.0f) {
             global |= (1L << BIT_OVERLAY_ENABLED);
         }
 
-        if (GLStateManager.lineStippleActive) {
+        if (glCtx.lineStippleActive) {
             global |= (1L << BIT_LINE_STIPPLE);
         }
 
         // Separate specular / color sum
-        if (GLStateManager.getLightingState().isEnabled()
-            && GLStateManager.getLightModel().colorControl == GL12.GL_SEPARATE_SPECULAR_COLOR) {
+        if (glCtx.lightingState.isEnabled()
+            && glCtx.lightModel.colorControl == GL12.GL_SEPARATE_SPECULAR_COLOR) {
             global |= (1L << BIT_SEPARATE_SPECULAR);
-        } else if (GLStateManager.getColorSumState().isEnabled()) {
+        } else if (glCtx.colorSumState.isEnabled()) {
             global |= (1L << BIT_COLOR_SUM);
         }
 
         // Per-unit state
+        final TextureUnitArray textures = glCtx.textures;
         int highestEnabled = -1;
         long unit0Bits = 0;
         for (int i = 0; i < MAX_UNITS; i++) {
             // Per Mesa - an enabled unit with no complete texture bound counts as disabled.
-            final boolean texEnabled = GLStateManager.getTextures().getTextureUnitStates(i).isEnabled() && GLStateManager.getTextures().getTextureUnitBindings(i).getBinding() != 0;
+            final boolean texEnabled = textures.getTextureUnitStates(i).isEnabled() && textures.getTextureUnitBindings(i).getBinding() != 0;
             if (texEnabled) highestEnabled = i;
 
-            final long unitBits = packUnit(i, texEnabled);
+            final long unitBits = packUnit(i, texEnabled, textures);
             if (i == 0) {
                 unit0Bits = unitBits;
             } else {
@@ -163,10 +177,10 @@ public final class FragmentKey {
         return Math.max(1, nrEnabled);
     }
 
-    private static long packUnit(int unitIndex, boolean texEnabled) {
+    private static long packUnit(int unitIndex, boolean texEnabled, TextureUnitArray textures) {
         if (!texEnabled) return 0;
 
-        final TexEnvState envState = GLStateManager.getTextures().getTexEnvState(unitIndex);
+        final TexEnvState envState = textures.getTexEnvState(unitIndex);
         final int mode = encodeTexEnvMode(envState.mode);
 
         long bits = 1L; // enabled
@@ -238,6 +252,8 @@ public final class FragmentKey {
     }
 
     public int fogMode()              { return (int) (packed[0] & 0x3); }
+    public boolean combinedGlint()    { return (packed[0] & (1L << BIT_COMBINED_GLINT)) != 0; }
+    public boolean glintReplaceAlpha() { return (packed[0] & (1L << BIT_GLINT_REPLACE_ALPHA)) != 0; }
     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; }
@@ -245,6 +261,7 @@ public final class FragmentKey {
     public boolean lineStipple()      { return ((packed[0] >> BIT_LINE_STIPPLE) & 1) != 0; }
     public int nrEnabledUnits()       { return (int) ((packed[0] >> BIT_NR_ENABLED_UNITS) & 0x7); }
     public boolean overlayEnabled()   { return ((packed[0] >> BIT_OVERLAY_ENABLED) & 1) != 0; }
+    public boolean overlayInstanced() { return ((packed[0] >> BIT_OVERLAY_INSTANCED) & 1) != 0; }
 
     private long unitBits(int i) {
         return (i == 0) ? (packed[0] >>> GLOBAL_BITS) : packed[i];
@@ -378,10 +395,9 @@ public final class FragmentKey {
             default -> "?";
         };
         final StringBuilder sb = new StringBuilder();
-        sb.append(String.format("FFPFragmentKey[fog=%s alpha=%b(%s) specSep=%b colorSum=%b overlay=%b units=%d",
-            fogName, alphaTestEnabled(),
-            alphaTestEnabled() ? String.format("0x%04X", decodeAlphaFunc(alphaTestFunc())) : "-",
-            separateSpecular(), colorSum(), overlayEnabled(), nrEnabledUnits()));
+        sb.append(String.format("FFPFragmentKey[fog=%s alpha=%b(%s) specSep=%b colorSum=%b overlay=%b units=%d", fogName, alphaTestEnabled(),
+            alphaTestEnabled() ? String.format("0x%04X", decodeAlphaFunc(alphaTestFunc())) : "-", separateSpecular(), colorSum(),
+            overlayEnabled() || overlayInstanced(), nrEnabledUnits()));
         for (int i = 0; i < nrEnabledUnits(); i++) {
             if (!unitEnabled(i)) {
                 sb.append(String.format(" u%d=OFF", i));

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

@@ -1,6 +1,7 @@
 package com.gtnewhorizons.angelica.glsm.ffp;
 
 import org.lwjgl.opengl.GL11;
+import org.embeddedt.embeddium.impl.render.shader.ShaderLoader;
 
 /**
  * Generates GLSL 330 core fragment shaders for FFP emulation.
@@ -17,6 +18,15 @@ public final class FragmentShaderGenerator {
 
         emitInputs(sb, key);
         emitUniforms(sb, key);
+        if (key.combinedGlint()) {
+            sb.append("#define GLINT_REPLACE_ALPHA ").append(key.glintReplaceAlpha() ? 1 : 0).append('\n');
+            sb.append("#define GLINT_FOG_MODE ").append(key.fogMode()).append('\n');
+            sb.append("#define GLINT_ALPHA_FUNC ").append(key.alphaTestEnabled() ? key.alphaTestFunc() : 7).append('\n');
+            sb.append("#define GLINT_OVERLAY ").append(key.overlayInstanced() ? 2 : key.overlayEnabled() ? 1 : 0).append('\n');
+            sb.append("#define GLINT_LIGHTMAP ").append(key.nrEnabledUnits() > 1 && key.unitEnabled(1) ? 1 : 0).append('\n');
+            sb.append(ShaderLoader.getShaderSource("angelica:combined_glint.frag.glsl"));
+            return sb.toString();
+        }
         sb.append("out vec4 fragColor;\n\n");
 
         sb.append("void main() {\n");
@@ -35,6 +45,9 @@ public final class FragmentShaderGenerator {
     private static void emitInputs(StringBuilder sb, FragmentKey key) {
         sb.append("// Inputs from vertex shader\n");
         sb.append("in vec4 v_Color;\n");
+        if (key.overlayInstanced()) {
+            sb.append("in vec4 v_Overlay;\n");
+        }
         if (key.separateSpecular()) {
             sb.append("in vec3 v_SpecularColor;\n");
         }
@@ -116,8 +129,11 @@ public final class FragmentShaderGenerator {
      * Emit the modern-style damage overlay mix.
      */
     private static void emitOverlay(StringBuilder sb, FragmentKey key) {
-        if (!key.overlayEnabled()) return;
-        sb.append("  color.rgb = mix(color.rgb, u_OverlayColor.rgb, u_OverlayColor.a);\n");
+        if (key.overlayInstanced()) {
+            sb.append("  color.rgb = mix(color.rgb, v_Overlay.rgb, v_Overlay.a);\n");
+        } else if (key.overlayEnabled()) {
+            sb.append("  color.rgb = mix(color.rgb, u_OverlayColor.rgb, u_OverlayColor.a);\n");
+        }
     }
 
     private static void emitSimpleUnit(StringBuilder sb, FragmentKey key, int unit, String texVar, String envColorVar, String prevVar, String assign) {

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

@@ -1,18 +1,84 @@
 package com.gtnewhorizons.angelica.glsm.ffp;
 
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.lwjgl.opengl.GL11;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutFloat;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutInt;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutLong;
+
 public final class InstancedAttribs {
 
-    public static final int LOC_MATRIX_COL0 = 5;
-    public static final int LOC_MATRIX_COL1 = 6;
-    public static final int LOC_MATRIX_COL2 = 7;
-    public static final int LOC_MATRIX_COL3 = 8;
-    public static final int LOC_COLOR = 9;
+    public static final int LOC_ROW0 = 5;
+    public static final int LOC_ROW1 = 6;
+    public static final int LOC_ROW2 = 7;
+    public static final int LOC_COLOR = 8;
+    public static final int LOC_OVERLAY = 9;
     public static final int LOC_LIGHTMAP = 10;
+    public static final int LOC_ENTITY = 11;
 
-    public static final int OFFSET_MATRIX = 0;
-    public static final int OFFSET_COLOR = 64;
-    public static final int OFFSET_LIGHTMAP = 68;
-    public static final int STRIDE = 80;
+    public static final int OFFSET_ROWS = 0;
+    public static final int OFFSET_COLOR = 48;
+    public static final int OFFSET_OVERLAY = 52;
+    public static final int OFFSET_ENTITY = 56;
+    public static final int HEAD_SIZE = 64;
+    public static final int OFFSET_LIGHTMAP = HEAD_SIZE;
+    public static final int STRIDE = 72;
+
+    public static void writeHead(long ptr, float[] colMajor, int off, int colorABGR, int overlayABGR, long entityInfo) {
+        writeRows(ptr, colMajor, off);
+        writeTail(ptr, colorABGR, overlayABGR, entityInfo);
+    }
+
+    private static void writeRows(long ptr, float[] colMajor, int off) {
+        for (int r = 0; r < 3; r++) {
+            final long row = ptr + OFFSET_ROWS + r * 16L;
+            memPutFloat(row, colMajor[off + r]);
+            memPutFloat(row + 4, colMajor[off + 4 + r]);
+            memPutFloat(row + 8, colMajor[off + 8 + r]);
+            memPutFloat(row + 12, colMajor[off + 12 + r]);
+        }
+    }
+
+    public static void writeTail(long ptr, int colorABGR, int overlayABGR, long entityInfo) {
+        memPutInt(ptr + OFFSET_COLOR, colorABGR);
+        memPutInt(ptr + OFFSET_OVERLAY, overlayABGR);
+        memPutLong(ptr + OFFSET_ENTITY, entityInfo);
+    }
+
+    public static void writeLightmap(long ptr, int packedLight) {
+        memPutFloat(ptr, packedLight & 0xFFFF);
+        memPutFloat(ptr + 4, (packedLight >>> 16) & 0xFFFF);
+    }
+
+    public static long packEntityInfo(int entity, int blockEntity, int item) {
+        return (entity & 0xFFFFL) | ((blockEntity & 0xFFFFL) << 16) | ((item & 0xFFFFL) << 32);
+    }
+
+    public static void pointHead(long base, int stride) {
+        for (int r = 0; r < 3; r++) {
+            GLStateManager.glVertexAttribPointer(LOC_ROW0 + r, 4, GL11.GL_FLOAT, false, stride, base + OFFSET_ROWS + r * 16L);
+        }
+        GLStateManager.glVertexAttribPointer(LOC_COLOR, 4, GL11.GL_UNSIGNED_BYTE, true, stride, base + OFFSET_COLOR);
+        GLStateManager.glVertexAttribPointer(LOC_OVERLAY, 4, GL11.GL_UNSIGNED_BYTE, true, stride, base + OFFSET_OVERLAY);
+        GLStateManager.glVertexAttribIPointer(LOC_ENTITY, 4, GL11.GL_SHORT, stride, base + OFFSET_ENTITY);
+    }
+
+    public static void pointTemplate(long base) {
+        pointHead(base, STRIDE);
+        GLStateManager.glVertexAttribPointer(LOC_LIGHTMAP, 2, GL11.GL_FLOAT, false, STRIDE, base + OFFSET_LIGHTMAP);
+    }
+
+    public static void enableHeadArrays() {
+        for (int loc = LOC_ROW0; loc <= LOC_ENTITY; loc++) {
+            enableInstanced(loc);
+        }
+    }
+
+    static void enableInstanced(int loc) {
+        GLStateManager.glEnableVertexAttribArray(loc);
+        GLStateManager.glVertexAttribDivisor(loc, 1);
+    }
 
     private InstancedAttribs() {}
 }

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

@@ -0,0 +1,145 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement;
+
+import java.util.ArrayList;
+
+public final class InstancedGlslHelpers {
+
+    private InstancedGlslHelpers() {}
+
+    public static String mat4FromRows(String row0, String row1, String row2) {
+        return "mat4("
+            + "vec4(" + row0 + ".x, " + row1 + ".x, " + row2 + ".x, 0.0), "
+            + "vec4(" + row0 + ".y, " + row1 + ".y, " + row2 + ".y, 0.0), "
+            + "vec4(" + row0 + ".z, " + row1 + ".z, " + row2 + ".z, 0.0), "
+            + "vec4(" + row0 + ".w, " + row1 + ".w, " + row2 + ".w, 1.0))";
+    }
+
+    public static String mat3FromRows(String row0, String row1, String row2) {
+        return "mat3("
+            + "normalize(vec3(" + row0 + ".x, " + row1 + ".x, " + row2 + ".x)), "
+            + "normalize(vec3(" + row0 + ".y, " + row1 + ".y, " + row2 + ".y)), "
+            + "normalize(vec3(" + row0 + ".z, " + row1 + ".z, " + row2 + ".z)))";
+    }
+
+    public static String particlePos(String centerHalf, String offset) {
+        return "vec4(" + centerHalf + ".xyz + " + offset + " * " + centerHalf + ".w, 1.0)";
+    }
+
+    public static String particleUv(String uv, String corner) {
+        return "vec4("
+            + "mix(" + uv + ".x, " + uv + ".z, " + corner + ".x), "
+            + "mix(" + uv + ".y, " + uv + ".w, " + corner + ".y), "
+            + "0.0, 1.0)";
+    }
+
+    // wHalfWidth is vanilla's rainXCoords table.
+    private static final String WEATHER_PROLOGUE = """
+        vec2 {p}wColumn = {span}.xy;
+        float {p}wBottom = {span}.z;
+        float {p}wTop = {span}.w;
+        vec2 {p}wLightmap = {params}.xy;
+        float {p}wHash = {params}.z;
+        bool {p}wSnow = {params}.w > 0.5;
+        vec3 {p}wTranslate = {p}WeatherParams0.xyz;
+        float {p}wInvRadius = {p}WeatherParams0.w;
+        vec2 {p}wCameraFrac = {p}WeatherParams1.xy;
+        float {p}wPartialTicks = {p}WeatherParams1.z;
+        float {p}wAge = {p}WeatherParams1.w;
+        float {p}wRainScroll = {p}WeatherParams2.x;
+        float {p}wSnowScroll = {p}WeatherParams2.y;
+        float {p}wStrength = {p}WeatherParams2.z;
+
+        vec2 {p}wHalfWidth = vec2(-{p}wColumn.y, {p}wColumn.x) * (0.5 / sqrt(dot({p}wColumn, {p}wColumn)));
+        vec2 {p}wCornerXZ = {p}wColumn + vec2(0.5) + ({corner}.x * 2.0 - 1.0) * {p}wHalfWidth;
+        float {p}wCornerY = mix({p}wBottom, {p}wTop, {corner}.y);
+        {vertex} = vec4(vec3({p}wCornerXZ.x, {p}wCornerY, {p}wCornerXZ.y) + {p}wTranslate, 1.0);
+
+        float {p}wDistance = length({p}wColumn + vec2(0.5) - {p}wCameraFrac) * {p}wInvRadius;
+        float {p}wFade = 1.0 - {p}wDistance * {p}wDistance;
+        float {p}wScroll;
+        vec2 {p}wDrift;
+        float {p}wAlpha;
+        if ({p}wSnow) {
+            {p}wScroll = ({p}wSnowScroll + {p}wPartialTicks) / 512.0;
+            {p}wDrift = vec2({jitter}.x + {p}wAge * 0.01 * {jitter}.y, {jitter}.z + {p}wAge * {jitter}.w * 0.001);
+            {p}wAlpha = {p}wFade * 0.3 + 0.5;
+        } else {
+            {p}wScroll = (mod({p}wRainScroll + {p}wHash, 32.0) + {p}wPartialTicks) / 32.0 * (3.0 + {jitter}.x);
+            {p}wDrift = vec2(0.0);
+            {p}wAlpha = {p}wFade * 0.5 + 0.5;
+        }
+
+        {tex0} = vec4({corner}.x + {p}wDrift.x, {p}wCornerY * 0.25 + {p}wScroll + {p}wDrift.y, 0.0, 1.0);
+        {tex1} = vec4({p}wLightmap, 0.0, 1.0);
+        {color} = vec4(1.0, 1.0, 1.0, {p}wAlpha * {p}wStrength);""";
+
+    public static String weatherPrologue(String uniformPrefix, String attribPrefix, String corner,
+        String vertex, String color, String tex0, String tex1, String sep) {
+        return WEATHER_PROLOGUE
+            .replace("{p}", uniformPrefix)
+            .replace("{span}", attribPrefix + "InstColumnSpan")
+            .replace("{jitter}", attribPrefix + "InstJitter")
+            .replace("{params}", attribPrefix + "InstWeatherParams")
+            .replace("{corner}", corner)
+            .replace("{vertex}", vertex)
+            .replace("{color}", color)
+            .replace("{tex0}", tex0)
+            .replace("{tex1}", tex1)
+            .replace("\n", sep);
+    }
+
+    public static String cubePrelude(String prefix, String mid, String delta, String normal, String tex, String sep) {
+        return "float " + prefix + "cubeMirror = " + tex + ".z < 0.0 ? 1.0 : 0.0;" + sep
+            + "vec2 " + prefix + "cubeMidU = " + mid + ".xy - " + prefix + "cubeMirror * " + normal + ".x;" + sep
+            + "vec2 " + prefix + "cubeU = " + prefix + "cubeMidU + (1.0 - 2.0 * " + prefix + "cubeMirror) * " + delta + ".xy;" + sep
+            + "vec2 " + prefix + "cubeV = " + mid + ".zw + " + delta + ".zw;";
+    }
+
+    public static String cubeUv(String tex, String lightScale, String uA, String uZ, String vA, String vZ) {
+        return "vec4("
+            + tex + ".x + " + uA + " * abs(" + tex + ".z) + " + uZ + " * " + lightScale + ".z, "
+            + tex + ".y + " + vA + " * " + tex + ".w + " + vZ + " * " + lightScale + ".w, "
+            + "0.0, 1.0)";
+    }
+
+    public static String[] attributeDecls(String prefix, Instancing kind) {
+        final ArrayList<String> decls = new ArrayList<>(9);
+        switch (kind) {
+            case NONE -> {}
+            case TEMPLATE -> addHead(decls, prefix, "vec2", "InstLightmap");
+            case CUBE -> {
+                decls.add(decl(VertexFormatElement.Usage.PRIMARY_UV.getAttributeLocation(), "vec4", prefix + "CubeMid"));
+                decls.add(decl(VertexFormatElement.Usage.SECONDARY_UV.getAttributeLocation(), "vec4", prefix + "CubeDelta"));
+                addHead(decls, prefix, "vec4", "InstLightmapScale");
+                decls.add(decl(CubeInstancedAttribs.LOC_CUBE_TEX, "vec4", prefix + "CubeTex"));
+            }
+            case PARTICLE -> {
+                decls.add(decl(ParticleInstancedAttribs.LOC_CENTER_HALF, "vec4", prefix + "InstCenterHalf"));
+                decls.add(decl(ParticleInstancedAttribs.LOC_UV, "vec4", prefix + "InstUv"));
+                decls.add(decl(ParticleInstancedAttribs.LOC_COLOR, "vec4", prefix + "InstColor"));
+                decls.add(decl(ParticleInstancedAttribs.LOC_LIGHTMAP, "vec2", prefix + "InstLightmap"));
+            }
+            case WEATHER -> {
+                decls.add(decl(WeatherInstancedAttribs.LOC_COLUMN_SPAN, "vec4", prefix + "InstColumnSpan"));
+                decls.add(decl(WeatherInstancedAttribs.LOC_JITTER, "vec4", prefix + "InstJitter"));
+                decls.add(decl(WeatherInstancedAttribs.LOC_PARAMS, "vec4", prefix + "InstWeatherParams"));
+            }
+        }
+        return decls.toArray(String[]::new);
+    }
+
+    private static void addHead(ArrayList<String> decls, String prefix, String lightmapType, String lightmapName) {
+        decls.add(decl(InstancedAttribs.LOC_ROW0, "vec4", prefix + "InstRow0"));
+        decls.add(decl(InstancedAttribs.LOC_ROW1, "vec4", prefix + "InstRow1"));
+        decls.add(decl(InstancedAttribs.LOC_ROW2, "vec4", prefix + "InstRow2"));
+        decls.add(decl(InstancedAttribs.LOC_COLOR, "vec4", prefix + "InstColor"));
+        decls.add(decl(InstancedAttribs.LOC_OVERLAY, "vec4", prefix + "InstOverlay"));
+        decls.add(decl(InstancedAttribs.LOC_LIGHTMAP, lightmapType, prefix + lightmapName));
+    }
+
+    private static String decl(int loc, String type, String name) {
+        return "layout(location = " + loc + ") in " + type + " " + name + ";";
+    }
+}

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

@@ -0,0 +1,21 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+public enum Instancing {
+    NONE(""),
+    TEMPLATE("_instanced"),
+    CUBE("_cubeinstanced"),
+    PARTICLE("_particleinstanced"),
+    WEATHER("_weatherinstanced");
+
+    public static final Instancing[] VALUES = values();
+
+    public final String variantSuffix;
+
+    Instancing(String variantSuffix) {
+        this.variantSuffix = variantSuffix;
+    }
+
+    public boolean hasInstanceHead() {
+        return this == TEMPLATE || this == CUBE;
+    }
+}

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

@@ -0,0 +1,50 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.lwjgl.opengl.GL11;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutFloat;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutInt;
+
+public final class ParticleInstancedAttribs {
+
+    public static final int LOC_CENTER_HALF = 5;
+    public static final int LOC_UV = 6;
+    public static final int LOC_COLOR = InstancedAttribs.LOC_COLOR;
+    public static final int LOC_LIGHTMAP = InstancedAttribs.LOC_LIGHTMAP;
+
+    public static final int OFFSET_CENTER_HALF = 0;
+    public static final int OFFSET_UV = 16;
+    public static final int OFFSET_COLOR = 32;
+    public static final int OFFSET_LIGHTMAP = 36;
+    public static final int STRIDE = 48;
+
+    public static void pointInstanceAttribs(long base) {
+        GLStateManager.glVertexAttribPointer(LOC_CENTER_HALF, 4, GL11.GL_FLOAT, false, STRIDE, base + OFFSET_CENTER_HALF);
+        GLStateManager.glVertexAttribPointer(LOC_UV, 4, GL11.GL_FLOAT, false, STRIDE, base + OFFSET_UV);
+        GLStateManager.glVertexAttribPointer(LOC_COLOR, 4, GL11.GL_UNSIGNED_BYTE, true, STRIDE, base + OFFSET_COLOR);
+        GLStateManager.glVertexAttribPointer(LOC_LIGHTMAP, 2, GL11.GL_FLOAT, false, STRIDE, base + OFFSET_LIGHTMAP);
+    }
+
+    static void enableInstanceArrays() {
+        InstancedAttribs.enableInstanced(LOC_CENTER_HALF);
+        InstancedAttribs.enableInstanced(LOC_UV);
+        InstancedAttribs.enableInstanced(LOC_COLOR);
+        InstancedAttribs.enableInstanced(LOC_LIGHTMAP);
+    }
+
+    public static void writeInstance(long ptr, float cx, float cy, float cz, float half, float u0, float v0, float u1, float v1, int colorABGR, int packedLight) {
+        memPutFloat(ptr + OFFSET_CENTER_HALF, cx);
+        memPutFloat(ptr + OFFSET_CENTER_HALF + 4, cy);
+        memPutFloat(ptr + OFFSET_CENTER_HALF + 8, cz);
+        memPutFloat(ptr + OFFSET_CENTER_HALF + 12, half);
+        memPutFloat(ptr + OFFSET_UV, u0);
+        memPutFloat(ptr + OFFSET_UV + 4, v0);
+        memPutFloat(ptr + OFFSET_UV + 8, u1);
+        memPutFloat(ptr + OFFSET_UV + 12, v1);
+        memPutInt(ptr + OFFSET_COLOR, colorABGR);
+        InstancedAttribs.writeLightmap(ptr + OFFSET_LIGHTMAP, packedLight);
+    }
+
+    private ParticleInstancedAttribs() {}
+}

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

@@ -0,0 +1,160 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.cel.api.util.NormI8;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.hooks.ImmediateExtendedAttribHandler;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAddress0;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAlloc;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memFree;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutFloat;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutInt;
+
+public final class ParticleQuadMesh {
+
+    public static final int VERTEX_FLAGS = VertexFlags.TEXTURE_BIT;
+
+    public static final int VERTEX_COUNT = 4;
+    private static final int VERTEX_STRIDE = 24;
+
+    private static final int OFFSET_OFFSET = 0;
+    private static final int OFFSET_CORNER = 12;
+    private static final int OFFSET_TANGENT = 20;
+
+    private static final float[] CORNER_A = { -1.0f, -1.0f, 1.0f, 1.0f };
+    private static final float[] CORNER_B = { -1.0f, 1.0f, 1.0f, -1.0f };
+
+    private static int vao;
+    private static int vbo;
+    private static ByteBuffer staging;
+    private static boolean written;
+    private static float lastRotX, lastRotXZ, lastRotZ, lastRotYZ, lastRotXY;
+
+    private ParticleQuadMesh() {}
+
+    public static float cornerA(int corner) {
+        return CORNER_A[corner];
+    }
+
+    public static float cornerB(int corner) {
+        return CORNER_B[corner];
+    }
+
+    public static float offsetX(float a, float b, float rotX, float rotYZ) {
+        return a * rotX + b * rotYZ;
+    }
+
+    public static float offsetY(float b, float rotXZ) {
+        return b * rotXZ;
+    }
+
+    public static float offsetZ(float a, float b, float rotZ, float rotXY) {
+        return a * rotZ + b * rotXY;
+    }
+
+    public static int vao() {
+        if (vao == 0) build();
+        return vao;
+    }
+
+    public static void update(float rotX, float rotXZ, float rotZ, float rotYZ, float rotXY) {
+        if (vao == 0) build();
+        if (written && rotX == lastRotX && rotXZ == lastRotXZ && rotZ == lastRotZ && rotYZ == lastRotYZ && rotXY == lastRotXY) {
+            return;
+        }
+        lastRotX = rotX;
+        lastRotXZ = rotXZ;
+        lastRotZ = rotZ;
+        lastRotYZ = rotYZ;
+        lastRotXY = rotXY;
+        written = true;
+
+        write(memAddress0(staging), rotX, rotXZ, rotZ, rotYZ, rotXY);
+        final int savedVBO = GLStateManager.getBoundVBO();
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, vbo);
+        staging.position(0).limit(VERTEX_COUNT * VERTEX_STRIDE);
+        GLStateManager.glBufferSubData(GL15.GL_ARRAY_BUFFER, 0L, staging);
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, savedVBO);
+    }
+
+    private static void write(long dst, float rotX, float rotXZ, float rotZ, float rotYZ, float rotXY) {
+        final int tangent = packTangent(rotX, 0.0f, rotZ);
+        long ptr = dst;
+        for (int i = 0; i < VERTEX_COUNT; i++) {
+            final float a = cornerA(i);
+            final float b = cornerB(i);
+            memPutFloat(ptr + OFFSET_OFFSET, offsetX(a, b, rotX, rotYZ));
+            memPutFloat(ptr + OFFSET_OFFSET + 4, offsetY(b, rotXZ));
+            memPutFloat(ptr + OFFSET_OFFSET + 8, offsetZ(a, b, rotZ, rotXY));
+            memPutFloat(ptr + OFFSET_CORNER, (a + 1.0f) * 0.5f);
+            memPutFloat(ptr + OFFSET_CORNER + 4, (b + 1.0f) * 0.5f);
+            memPutInt(ptr + OFFSET_TANGENT, tangent);
+            ptr += VERTEX_STRIDE;
+        }
+    }
+
+    private static int packTangent(float x, float y, float z) {
+        final float lenSq = x * x + y * y + z * z;
+        final float nx, ny, nz;
+        if (lenSq < 1.0e-12f) {
+            nx = 1.0f;
+            ny = 0.0f;
+            nz = 0.0f;
+        } else {
+            final float inv = (float) (1.0 / Math.sqrt(lenSq));
+            nx = x * inv;
+            ny = y * inv;
+            nz = z * inv;
+        }
+        return NormI8.pack(nx, ny, nz) | (127 << 24);
+    }
+
+    private static void build() {
+        final int savedVAO = GLStateManager.getBoundVAO();
+        final int savedVBO = GLStateManager.getBoundVBO();
+        vao = GLStateManager.glGenVertexArrays();
+        GLStateManager.glBindVertexArray(vao);
+        vbo = GLStateManager.glGenBuffers();
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, vbo);
+        GLStateManager.glBufferData(GL15.GL_ARRAY_BUFFER, (long) VERTEX_COUNT * VERTEX_STRIDE, GL15.GL_DYNAMIC_DRAW);
+
+        attrib(VertexFormatElement.Usage.POSITION.getAttributeLocation(), 3, GL11.GL_FLOAT, false, OFFSET_OFFSET);
+        attrib(VertexFormatElement.Usage.PRIMARY_UV.getAttributeLocation(), 2, GL11.GL_FLOAT, false, OFFSET_CORNER);
+        attrib(ImmediateExtendedAttribHandler.LOC_TANGENT, 4, GL11.GL_BYTE, true, OFFSET_TANGENT);
+
+        ParticleInstancedAttribs.enableInstanceArrays();
+
+        GLStateManager.glBindVertexArray(savedVAO);
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, savedVBO);
+
+        if (staging == null) staging = memAlloc(VERTEX_COUNT * VERTEX_STRIDE);
+        written = false;
+    }
+
+    private static void attrib(int loc, int size, int type, boolean normalized, int offset) {
+        GLStateManager.glEnableVertexAttribArray(loc);
+        GLStateManager.glVertexAttribPointer(loc, size, type, normalized, VERTEX_STRIDE, offset);
+    }
+
+    public static void delete() {
+        if (vbo != 0) {
+            GLStateManager.glDeleteBuffers(vbo);
+            vbo = 0;
+        }
+        if (vao != 0) {
+            GLStateManager.glDeleteVertexArrays(vao);
+            vao = 0;
+        }
+        if (staging != null) {
+            memFree(staging);
+            staging = null;
+        }
+        written = false;
+    }
+}

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

@@ -9,7 +9,6 @@ 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;
 
 
@@ -271,25 +270,6 @@ public class ShaderCache {
         }
     }
 
-    /** 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;
     }

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

@@ -4,12 +4,13 @@ import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
 import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormat;
 import com.gtnewhorizons.angelica.config.SystemProperties;
 import com.gtnewhorizons.angelica.glsm.CompatUniformManager;
+import com.gtnewhorizons.angelica.glsm.GLContextState;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.hooks.DeferredBlendHandler;
 import com.gtnewhorizons.angelica.glsm.hooks.GLSMHooks;
-import com.gtnewhorizons.angelica.glsm.hooks.GLSMInitConfig;
 import com.gtnewhorizons.angelica.glsm.QuadConverter;
 import com.gtnewhorizons.angelica.glsm.profiling.Tracy;
+import com.gtnewhorizons.angelica.glsm.stacks.StackIdAllocator;
 import com.gtnewhorizons.angelica.glsm.stacks.Vec3fStack;
 import com.gtnewhorizons.angelica.glsm.stacks.Vec4fStack;
 import com.gtnewhorizons.angelica.glsm.streaming.TessellatorStreamingDrawer;
@@ -26,45 +27,42 @@ import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACK
  */
 public final class ShaderManager {
 
-    private static final class Holder {
-
-        static final ShaderManager INSTANCE = new ShaderManager();
-    }
-
-    private final ShaderCache cache = new ShaderCache();
+    private static final ShaderCache cache = new ShaderCache();
     private final Uniforms uniforms = new Uniforms();
 
     @Getter
-    private boolean active = false;
+    private boolean active;
     private Program currentProgram = null;
-    private int lastBoundProgramId = -1;
+    private int lastBoundProgramId;
     private long currentVertexKeyPacked = Long.MIN_VALUE;
     private final long[] currentFKScratch = new long[FragmentKey.MAX_UNITS];
     private final long[] currentFKPacked = new long[FragmentKey.MAX_UNITS];
     private int currentFKLen = 0;
 
-    @Getter private static final Vector3f currentNormal = new Vector3f(0.0f, 0.0f, 1.0f);
-    private static final Vector4f[] currentTexCoords = {
+    public final Vector3f currentNormal = new Vector3f(0.0f, 0.0f, 1.0f);
+    public final Vector4f[] currentTexCoords = {
         new Vector4f(0.0f, 0.0f, 0.0f, 1.0f),
         new Vector4f(0.0f, 0.0f, 0.0f, 1.0f),
         new Vector4f(0.0f, 0.0f, 0.0f, 1.0f),
         new Vector4f(0.0f, 0.0f, 0.0f, 1.0f),
     };
-    @Getter private static final Vec3fStack normalStack = new Vec3fStack(currentNormal);
-    @Getter private static final Vec4fStack texCoordStack = new Vec4fStack(currentTexCoords[0]);
-    @Getter private static int normalGeneration;
-    @Getter private static int texCoordGeneration;
+    public final Vec3fStack normalStack = new Vec3fStack(currentNormal, StackIdAllocator.nextId());
+    public final Vec4fStack texCoordStack = new Vec4fStack(currentTexCoords[0], StackIdAllocator.nextId());
+    public int normalGeneration;
+    public int texCoordGeneration;
 
     private int preDrawCalls;
     private int lastFramePreDrawCalls;
 
     public static long variantSwitches;
 
-    public static Vector4f getCurrentTexCoord() { return currentTexCoords[0]; }
-    public static Vector4f getCurrentTexCoord(int unit) { return currentTexCoords[unit]; }
-    @Getter private boolean enabled = false;
+    public static Vector3f getCurrentNormal() { return GLStateManager.ctx().ffp.currentNormal; }
+    public static Vector4f getCurrentTexCoord() { return GLStateManager.ctx().ffp.currentTexCoords[0]; }
+    public static Vec3fStack getNormalStack() { return GLStateManager.ctx().ffp.normalStack; }
+    public static Vec4fStack getTexCoordStack() { return GLStateManager.ctx().ffp.texCoordStack; }
+    @Getter private static boolean enabled = false;
 
-    private ShaderManager() {
+    static {
         cache.setDumpDir(SystemProperties.shaderDumpDir("ffp"));
         VertexFormat.registerSetupBufferStateOverride((format, offset) -> {
             VAOManager.setCurrentVertexFlags(format.getVertexFlags());
@@ -72,18 +70,20 @@ public final class ShaderManager {
         });
     }
 
-    public static ShaderManager getInstance() {
-        return Holder.INSTANCE;
+    public ShaderManager() {
+        active = enabled;
+        lastBoundProgramId = enabled ? 0 : -1;
     }
 
-    public void enable() {
+    public static ShaderManager getInstance() {
+        return GLStateManager.ctx().ffp;
+    }
+
+    public static void enable() {
         warmUp();
         enabled = true;
-
-        if (GLStateManager.getActiveProgram() == 0) {
-            activate();
-        }
-
+        final GLContextState glCtx = GLStateManager.ctx();
+        if (glCtx.activeProgram == 0) glCtx.ffp.activate();
         GLStateManager.LOGGER.info("FFP shader emulation enabled");
     }
 
@@ -97,6 +97,8 @@ public final class ShaderManager {
             final long vkPacked = VertexKey.packFromState(true, true, true, true, fragMask);
             final VertexKey vk = VertexKey.fromPacked(vkPacked);
             VertexShaderGenerator.generate(vk);
+            VertexShaderGenerator.generate(VertexKey.fromPacked(VertexKey.withInstancing(vkPacked, Instancing.CUBE)));
+            VertexShaderGenerator.generate(VertexKey.fromPacked(VertexKey.withInstancing(vkPacked, Instancing.PARTICLE)));
             FragmentShaderGenerator.generate(FragmentKey.fromPacked(fkScratch, fkLen));
             GeometryShaderGenerator.generate(vk);
             final Class<?>[] touched = { Program.class, ShaderCache.class, TessellatorStreamingDrawer.class, QuadConverter.class };
@@ -108,7 +110,7 @@ public final class ShaderManager {
         }
     }
 
-    public void disable() {
+    public static void disable() {
         enabled = false;
     }
 
@@ -117,6 +119,13 @@ public final class ShaderManager {
         lastBoundProgramId = GLStateManager.getActiveProgram();
     }
 
+    public void invalidateProgram() {
+        lastBoundProgramId = -1;
+        currentProgram = null;
+        currentVertexKeyPacked = Long.MIN_VALUE;
+        uniforms.invalidateBinding();
+    }
+
     public void deactivate() {
         active = false;
         currentProgram = null;
@@ -126,37 +135,38 @@ public final class ShaderManager {
         GLStateManager.forceAttribDefaultsDirty();
     }
 
-    public void preDraw() {
+    public void preDraw(GLContextState glCtx) {
+        GLSMHooks.resolvePendingProgram();
         final DeferredBlendHandler bh = GLSMHooks.blendHandler;
         if (bh != null) bh.flushDeferredBlend();
 
         // Handle FFP & Iris uniforms
-        final int currentProgramId = GLStateManager.getActiveProgram();
+        final int currentProgramId = glCtx.activeProgram;
         if (currentProgramId != 0) {
-            if (!CompatUniformManager.refreshCompatUniforms(currentProgramId)) {
+            if (!CompatUniformManager.refreshCompatUniforms(currentProgramId, glCtx)) {
                 return; // Don't emulate FFP on non-iris core shaders
             }
         }
 
-        final int vertexFlags = VAOManager.getCurrentVertexFlags();
+        final int vertexFlags = glCtx.vaos.getVertexFlags();
         final boolean hasColor = (vertexFlags & VertexFlags.COLOR_BIT) != 0;
         final boolean hasNormal =   (vertexFlags & VertexFlags.NORMAL_BIT) != 0;
         final boolean hasTexCoord = (vertexFlags & VertexFlags.TEXTURE_BIT) != 0;
         final boolean hasLightmap = (vertexFlags & VertexFlags.BRIGHTNESS_BIT) != 0;
-        GLStateManager.flushDeferredVertexAttribs(hasColor, hasNormal, hasTexCoord, hasLightmap);
+        GLStateManager.flushDeferredVertexAttribs(glCtx, hasColor, hasNormal, hasTexCoord, hasLightmap);
 
         if (!active) return;
 
         preDrawCalls++;
-        final int fkLen = FragmentKey.packFromState(currentFKScratch);
+        final int fkLen = FragmentKey.packFromState(currentFKScratch, glCtx);
         final int fragMask = FragmentKey.unitMaskFromPacked(currentFKScratch, fkLen);
-        final long vkPacked = VertexKey.packFromState(hasColor, hasNormal, hasTexCoord, hasLightmap, fragMask);
+        final long vkPacked = VertexKey.packFromState(hasColor, hasNormal, hasTexCoord, hasLightmap, fragMask, glCtx);
 
         if (vkPacked != currentVertexKeyPacked || !Arrays.equals(currentFKScratch, 0, fkLen, currentFKPacked, 0, currentFKLen)) {
             commitVariant(vkPacked, fkLen);
         }
 
-        uploadUniforms();
+        uploadUniforms(glCtx);
     }
 
     private void commitVariant(long vkPacked, int fkLen) {
@@ -172,48 +182,38 @@ public final class ShaderManager {
         }
     }
 
-    private void uploadUniforms() {
+    private void uploadUniforms(GLContextState glCtx) {
         if (currentProgram != null) {
-            uniforms.upload();
+            uniforms.upload(glCtx);
         }
     }
 
     public static void endFrame() {
-        final ShaderManager sm = Holder.INSTANCE;
+        final ShaderManager sm = GLStateManager.ctx().ffp;
         sm.lastFramePreDrawCalls = sm.preDrawCalls;
         sm.preDrawCalls = 0;
         sm.uniforms.endFrame();
         FfpExtendedAttribs.endFrame();
     }
 
-    public static void setCurrentNormal(float x, float y, float z) {
+    public void setNormal(float x, float y, float z) {
+        normalStack.beforeModify();
         currentNormal.set(x, y, z);
         normalGeneration++;
     }
 
-    public static void setCurrentTexCoord(float s, float t, float r, float q) {
+    public void setTexCoord(float s, float t, float r, float q) {
+        texCoordStack.beforeModify();
         currentTexCoords[0].set(s, t, r, q);
         texCoordGeneration++;
     }
 
-    public static void setCurrentTexCoord(int unit, float s, float t, float r, float q) {
+    public void setTexCoord(int unit, float s, float t, float r, float q) {
+        if (unit == 0) texCoordStack.beforeModify();
         currentTexCoords[unit].set(s, t, r, q);
         texCoordGeneration++;
     }
 
-    public static void bumpNormalGeneration() { normalGeneration++; }
-    public static void bumpTexCoordGeneration() { texCoordGeneration++; }
-
-    public void destroy() {
-        cache.destroy();
-        uniforms.destroy();
-        final GLSMInitConfig config = GLStateManager.getInitConfig();
-        if (config != null && config.getStreamingDrawerDestroy() != null) config.getStreamingDrawerDestroy().run();
-        QuadConverter.destroy();
-        active = false;
-        currentProgram = null;
-    }
-
     public String getDebugInfo() {
         return String.format("FFP: %d programs (%d vert, %d frag variants) | UBO: %d/%d draws wrote (mat %d, light %d, frag %d, misc %d)",
             cache.getProgramCount(), cache.getVertexVariantCount(), cache.getFragmentVariantCount(),

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

@@ -1,5 +1,6 @@
 package com.gtnewhorizons.angelica.glsm.ffp;
 
+import com.gtnewhorizons.angelica.glsm.GLContextState;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.ClipPlaneState;
 import com.gtnewhorizons.angelica.glsm.states.FogState;
@@ -7,9 +8,9 @@ import com.gtnewhorizons.angelica.glsm.states.LightState;
 import com.gtnewhorizons.angelica.glsm.states.LineState;
 import com.gtnewhorizons.angelica.glsm.states.MaterialState;
 import com.gtnewhorizons.angelica.glsm.states.TexGenState;
+import com.gtnewhorizons.angelica.glsm.states.TextureUnitArray;
 import com.gtnewhorizons.angelica.glsm.states.ViewportState;
 import com.gtnewhorizons.angelica.glsm.streaming.UniformRingBuffer;
-import com.gtnewhorizons.angelica.glsm.hooks.GLSMConfig;
 import org.joml.Math;
 import org.joml.Matrix3f;
 import org.joml.Matrix4f;
@@ -47,6 +48,7 @@ public class Uniforms {
     private float lightmapX = Float.NaN, lightmapY = Float.NaN, lineWidth = Float.NaN;
     private int viewportX = Integer.MIN_VALUE, viewportY = Integer.MIN_VALUE, viewportWidth = -1, viewportHeight = -1;
     private int lineStipple = -1;
+    private int weatherGen = -1;
 
     int blockWrites;
     int blockSkips;
@@ -81,66 +83,67 @@ public class Uniforms {
     private static final double LN2 = java.lang.Math.log(2.0);
     private static final double SQRT_LN2 = java.lang.Math.sqrt(LN2);
 
-    public void upload() {
+    public void upload(GLContextState glCtx) {
         boolean dirty = false;
         contentChanged = false;
 
-        final int mvG = GLStateManager.getMvGeneration();
-        final int projG = GLStateManager.getProjGeneration();
+        final int mvG = glCtx.mvGeneration;
+        final int projG = glCtx.projGeneration;
         final boolean mvChanged = mvG != mvGen;
         final boolean projChanged = projG != projGen;
         if (mvChanged || projChanged) {
-            stageMatrices(mvChanged, projChanged);
+            stageMatrices(mvChanged, projChanged, glCtx);
             mvGen = mvG;
             projGen = projG;
             stagedMatrices++;
             dirty = true;
         }
-        final int mvLinG = GLStateManager.getMvLinearGeneration();
+        final int mvLinG = glCtx.mvLinearGeneration;
         if (mvLinG != mvLinearGen) {
-            stageNormalMatrix();
+            stageNormalMatrix(glCtx);
             mvLinearGen = mvLinG;
             dirty = true;
         }
-        final int texMatG = GLStateManager.getTexMatrixGeneration();
+        final int texMatG = glCtx.texMatrixGeneration;
         if (texMatG != texMatGen) {
-            stageTextureMatrices();
+            stageTextureMatrices(glCtx);
             texMatGen = texMatG;
             dirty = true;
         }
-        final int litG = GLStateManager.getLightingGeneration();
+        final int litG = glCtx.lightingGeneration;
         if (litG != lightingGen) {
-            stageLighting();
+            stageLighting(glCtx);
             lightingGen = litG;
             stagedLighting++;
             dirty = true;
         }
-        final int colG = GLStateManager.getColorGeneration();
+        final int colG = glCtx.colorGeneration;
         if (colG != colorGen) {
-            stageCurrentColor();
+            stageCurrentColor(glCtx);
             colorGen = colG;
             stagedColor++;
             dirty = true;
         }
-        final int normG = ShaderManager.getNormalGeneration();
+        final ShaderManager ffp = glCtx.ffp;
+        final int normG = ffp.normalGeneration;
         if (normG != normalGen) {
-            final Vector3f normal = ShaderManager.getCurrentNormal();
+            final Vector3f normal = ffp.currentNormal;
             putVec3(FFPUniformBlock.CURRENT_NORMAL, normal.x, normal.y, normal.z);
             normalGen = normG;
             stagedNormal++;
             dirty = true;
         }
-        final int tcG = ShaderManager.getTexCoordGeneration();
+        final int tcG = ffp.texCoordGeneration;
         if (tcG != texCoordGen) {
-            putVec4(FFPUniformBlock.CURRENT_TEX_COORD_0, ShaderManager.getCurrentTexCoord(0));
-            putVec4(FFPUniformBlock.CURRENT_TEX_COORD_2, ShaderManager.getCurrentTexCoord(2));
-            putVec4(FFPUniformBlock.CURRENT_TEX_COORD_3, ShaderManager.getCurrentTexCoord(3));
+            putVec4(FFPUniformBlock.CURRENT_TEX_COORD_0, ffp.currentTexCoords[0]);
+            putVec4(FFPUniformBlock.CURRENT_TEX_COORD_2, ffp.currentTexCoords[2]);
+            putVec4(FFPUniformBlock.CURRENT_TEX_COORD_3, ffp.currentTexCoords[3]);
             texCoordGen = tcG;
             stagedTexCoord++;
             dirty = true;
         }
-        final float brightX = GLSMConfig.lastBrightnessX;
-        final float brightY = GLSMConfig.lastBrightnessY;
+        final float brightX = glCtx.lastBrightnessX;
+        final float brightY = glCtx.lastBrightnessY;
         if (brightX != lightmapX || brightY != lightmapY) {
             putFloat(FFPUniformBlock.CURRENT_LIGHTMAP_COORD, brightX);
             putFloat(FFPUniformBlock.CURRENT_LIGHTMAP_COORD + 4, brightY);
@@ -149,35 +152,36 @@ public class Uniforms {
             stagedLightmap++;
             dirty = true;
         }
-        final int tgG = GLStateManager.getTexGenGeneration();
+        final int tgG = glCtx.texGenGeneration;
         if (tgG != texGenGen) {
-            stageTexGen();
+            stageTexGen(glCtx);
             texGenGen = tgG;
             stagedTexGen++;
             dirty = true;
         }
-        final int cpG = GLStateManager.getClipPlaneGeneration();
+        final int cpG = glCtx.clipPlaneGeneration;
         if (cpG != clipPlaneGen) {
-            stageClipPlanes();
+            stageClipPlanes(glCtx);
             clipPlaneGen = cpG;
             stagedClipPlanes++;
             dirty = true;
         }
-        final int fragG = GLStateManager.getFragmentGeneration();
+        final int fragG = glCtx.fragmentGeneration;
         if (fragG != fragmentGen) {
-            stageFragment();
+            stageFragment(glCtx);
             fragmentGen = fragG;
             stagedFragment++;
             dirty = true;
         }
-        final float lw = GLStateManager.getLineState().getWidth();
+        final LineState line = glCtx.lineState;
+        final float lw = line.getWidth();
         if (lw != lineWidth) {
             putFloat(FFPUniformBlock.LINE_WIDTH, lw);
             lineWidth = lw;
             stagedMisc++;
             dirty = true;
         }
-        final ViewportState vp = GLStateManager.getViewportState();
+        final ViewportState vp = glCtx.viewportState;
         if (vp.x != viewportX || vp.y != viewportY || vp.width != viewportWidth || vp.height != viewportHeight) {
             putFloat(FFPUniformBlock.VIEWPORT_SIZE, vp.width);
             putFloat(FFPUniformBlock.VIEWPORT_SIZE + 4, vp.height);
@@ -189,8 +193,13 @@ public class Uniforms {
             stagedMisc++;
             dirty = true;
         }
-        final LineState line = GLStateManager.getLineState();
-        final int stippleFactor = line.getStippleFactor() < 1 ? 1 : line.getStippleFactor();
+        if (WeatherParams.generation != weatherGen) {
+            stageWeatherParams();
+            weatherGen = WeatherParams.generation;
+            stagedMisc++;
+            dirty = true;
+        }
+        final int stippleFactor = Math.max(line.getStippleFactor(), 1);
         final int stipplePacked = (line.getStipplePattern() & 0xFFFF) | (stippleFactor << 16);
         if (stipplePacked != lineStipple) {
             putInt(FFPUniformBlock.LINE_STIPPLE, stipplePacked);
@@ -215,9 +224,9 @@ public class Uniforms {
         }
     }
 
-    private void stageMatrices(boolean mvChanged, boolean projChanged) {
-        final Matrix4f mv = GLStateManager.getModelViewMatrix();
-        final Matrix4f proj = GLStateManager.getProjectionMatrix();
+    private void stageMatrices(boolean mvChanged, boolean projChanged, GLContextState glCtx) {
+        final Matrix4f mv = glCtx.modelViewMatrix;
+        final Matrix4f proj = glCtx.projectionMatrix;
         if (mvChanged) {
             putMat4(FFPUniformBlock.MODEL_VIEW_MATRIX, mv);
         }
@@ -228,8 +237,8 @@ public class Uniforms {
         putMat4(FFPUniformBlock.MVP_MATRIX, mvpMatrix);
     }
 
-    private void stageNormalMatrix() {
-        GLStateManager.getModelViewMatrix().normal(normalMatrix);
+    private void stageNormalMatrix(GLContextState glCtx) {
+        glCtx.modelViewMatrix.normal(normalMatrix);
         putMat3(FFPUniformBlock.NORMAL_MATRIX, normalMatrix);
         putFloat(FFPUniformBlock.NORMAL_SCALE, rescaleFactor(normalMatrix, tempVec3));
     }
@@ -239,18 +248,19 @@ public class Uniforms {
         return f > 1.0e-12f ? 1.0f / (float) Math.sqrt(f) : 1.0f;
     }
 
-    private void stageTextureMatrices() {
-        putMat4(FFPUniformBlock.TEXTURE_MATRIX_0, GLStateManager.getTextures().getTextureUnitMatrix(0));
-        putMat4(FFPUniformBlock.TEXTURE_MATRIX_2, GLStateManager.getTextures().getTextureUnitMatrix(2));
-        putMat4(FFPUniformBlock.TEXTURE_MATRIX_3, GLStateManager.getTextures().getTextureUnitMatrix(3));
-        putMat4(FFPUniformBlock.LIGHTMAP_TEXTURE_MATRIX, GLStateManager.getTextures().getTextureUnitMatrix(1));
+    private void stageTextureMatrices(GLContextState glCtx) {
+        final TextureUnitArray textures = glCtx.textures;
+        putMat4(FFPUniformBlock.TEXTURE_MATRIX_0, textures.getTextureUnitMatrix(0));
+        putMat4(FFPUniformBlock.TEXTURE_MATRIX_2, textures.getTextureUnitMatrix(2));
+        putMat4(FFPUniformBlock.TEXTURE_MATRIX_3, textures.getTextureUnitMatrix(3));
+        putMat4(FFPUniformBlock.LIGHTMAP_TEXTURE_MATRIX, textures.getTextureUnitMatrix(1));
     }
 
-    private void stageLighting() {
-        final MaterialState mat = GLStateManager.getFrontMaterial();
-        final Vector4f lmAmbient = GLStateManager.getLightModel().ambient;
-        final LightState light0 = GLStateManager.getLightDataStates()[0];
-        final LightState light1 = GLStateManager.getLightDataStates()[1];
+    private void stageLighting(GLContextState glCtx) {
+        final MaterialState mat = glCtx.frontMaterial;
+        final Vector4f lmAmbient = glCtx.lightModel.ambient;
+        final LightState light0 = glCtx.lightDataStates[0];
+        final LightState light1 = glCtx.lightDataStates[1];
 
         putVec4(FFPUniformBlock.LIGHT_MODEL_AMBIENT, lmAmbient);
         putVec4(FFPUniformBlock.MATERIAL_EMISSION, mat.emission);
@@ -284,8 +294,8 @@ public class Uniforms {
         putVec3(offset, lightVal.x * materialVal.x, lightVal.y * materialVal.y, lightVal.z * materialVal.z);
     }
 
-    private void stageCurrentColor() {
-        final var color = GLStateManager.getColor();
+    private void stageCurrentColor(GLContextState glCtx) {
+        final var color = glCtx.color;
         putVec4(FFPUniformBlock.CURRENT_COLOR,
             Math.clamp(0f, 1f, color.getRed()),
             Math.clamp(0f, 1f, color.getGreen()),
@@ -293,8 +303,8 @@ public class Uniforms {
             Math.clamp(0f, 1f, color.getAlpha()));
     }
 
-    private void stageTexGen() {
-        final TexGenState tg = GLStateManager.getTextures().getTexGenState(0);
+    private void stageTexGen(GLContextState glCtx) {
+        final TexGenState tg = glCtx.textures.getTexGenState(0);
         putPlane(FFPUniformBlock.TEX_GEN_OBJ_PLANE_S, tg.getObjectPlane(GL11.GL_S));
         putPlane(FFPUniformBlock.TEX_GEN_OBJ_PLANE_T, tg.getObjectPlane(GL11.GL_T));
         putPlane(FFPUniformBlock.TEX_GEN_OBJ_PLANE_R, tg.getObjectPlane(GL11.GL_R));
@@ -305,8 +315,8 @@ public class Uniforms {
         putPlane(FFPUniformBlock.TEX_GEN_EYE_PLANE_Q, tg.getEyePlane(GL11.GL_Q));
     }
 
-    private void stageClipPlanes() {
-        final ClipPlaneState cps = GLStateManager.getClipPlaneState();
+    private void stageClipPlanes(GLContextState glCtx) {
+        final ClipPlaneState cps = glCtx.clipPlaneState;
         clipPlaneBuf.clear();
         for (int i = 0; i < GLStateManager.MAX_CLIP_PLANES; i++) {
             cps.putEyePlane(i, clipPlaneBuf);
@@ -317,24 +327,24 @@ public class Uniforms {
         }
     }
 
-    private void stageFragment() {
-        putFloat(FFPUniformBlock.ALPHA_REF, GLStateManager.getAlphaState().getReference());
+    private void stageFragment(GLContextState glCtx) {
+        putFloat(FFPUniformBlock.ALPHA_REF, glCtx.alphaState.getReference());
 
         for (int i = 0; i < 4; i++) {
-            final var envState = GLStateManager.getTextures().getTexEnvState(i);
+            final var envState = glCtx.textures.getTexEnvState(i);
             putVec4(FFPUniformBlock.TEX_ENV_COLOR_0 + i * 16,
                 envState.envColorR, envState.envColorG, envState.envColorB, envState.envColorA);
         }
 
         putVec4(FFPUniformBlock.OVERLAY_COLOR,
-            GLStateManager.getOverlayR(), GLStateManager.getOverlayG(),
-            GLStateManager.getOverlayB(), GLStateManager.getOverlayA());
+            glCtx.overlayR, glCtx.overlayG,
+            glCtx.overlayB, glCtx.overlayA);
 
-        final var secondary = GLStateManager.getSecondaryColor();
+        final var secondary = glCtx.secondaryColor;
         putVec3(FFPUniformBlock.SECONDARY_COLOR, secondary.getRed(), secondary.getGreen(), secondary.getBlue());
 
         // Mesa STATE_FOG_PARAMS_OPTIMIZED
-        final FogState fog = GLStateManager.getFogState();
+        final FogState fog = glCtx.fogState;
         final float start = fog.getStart();
         final float end = fog.getEnd();
         final float density = fog.getDensity();
@@ -376,6 +386,15 @@ public class Uniforms {
         putVec3(offset + 32, m.m20(), m.m21(), m.m22());
     }
 
+    private void stageWeatherParams() {
+        putVec4(FFPUniformBlock.WEATHER_PARAMS_0, WeatherParams.translateX, WeatherParams.translateY,
+            WeatherParams.translateZ, WeatherParams.invRadius);
+        putVec4(FFPUniformBlock.WEATHER_PARAMS_1, WeatherParams.cameraFracX, WeatherParams.cameraFracZ,
+            WeatherParams.partialTicks, WeatherParams.age);
+        putVec4(FFPUniformBlock.WEATHER_PARAMS_2, WeatherParams.rainScroll, WeatherParams.snowScroll,
+            WeatherParams.rainStrength, 0.0f);
+    }
+
     private void putVec4(int offset, Vector4f v) {
         putVec4(offset, v.x, v.y, v.z, v.w);
     }
@@ -427,6 +446,10 @@ public class Uniforms {
         stagedMisc = 0;
     }
 
+    void invalidateBinding() {
+        bound = false;
+    }
+
     UniformRingBuffer getRing() {
         return ring;
     }

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

@@ -0,0 +1,161 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.cel.api.util.NormI8;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.hooks.ImmediateExtendedAttribHandler;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAddress0;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memAlloc;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memFree;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutFloat;
+import static com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities.memPutInt;
+
+public final class UnitCubeMesh {
+
+    public static final int VERTEX_FLAGS = VertexFlags.COLOR_BIT | VertexFlags.TEXTURE_BIT | VertexFlags.NORMAL_BIT;
+
+    public static final int FACE_COUNT = 6;
+    public static final int VERTEX_COUNT = 24;
+    public static final int VERTEX_STRIDE = 64;
+
+    public static final int OFFSET_POSITION = 0;
+    private static final int OFFSET_COLOR = 12;
+    public static final int OFFSET_MID = 16;
+    public static final int OFFSET_DELTA = 32;
+    public static final int OFFSET_NORMAL = 48;
+    public static final int OFFSET_TANGENT = 60;
+
+    public static final float[][] CORNERS = {
+        { 0, 0, 0 }, { 1, 0, 0 }, { 1, 1, 0 }, { 0, 1, 0 },
+        { 0, 0, 1 }, { 1, 0, 1 }, { 1, 1, 1 }, { 0, 1, 1 },
+    };
+
+    public record Span(int a, int z) {
+        public int texels(int sizeA, int sizeZ) {
+            return a * sizeA + z * sizeZ;
+        }
+    }
+
+    public record Net(Span uLow, Span uHigh, Span vLow, Span vHigh) {
+        public Span u(int vertex) {
+            return vertex == 0 || vertex == 3 ? uHigh : uLow;
+        }
+
+        public Span v(int vertex) {
+            return vertex >= 2 ? vHigh : vLow;
+        }
+    }
+
+    public record Face(int[] corners, float[] normal, float[] tangent, Net net) {}
+
+    public static final Face[] FACES = {
+        new Face(new int[] { 5, 1, 2, 6 }, new float[] { 1, 0, 0 }, new float[] { 0, 0, 1, 1 }, new Net(new Span(1, 1), new Span(1, 2), new Span(0, 1), new Span(1, 1))),
+        new Face(new int[] { 0, 4, 7, 3 }, new float[] { -1, 0, 0 }, new float[] { 0, 0, -1, 1 }, new Net(new Span(0, 0), new Span(0, 1), new Span(0, 1), new Span(1, 1))),
+        new Face(new int[] { 5, 4, 0, 1 }, new float[] { 0, -1, 0 }, new float[] { 1, 0, 0, 1 }, new Net(new Span(0, 1), new Span(1, 1), new Span(0, 0), new Span(0, 1))),
+        new Face(new int[] { 2, 3, 7, 6 }, new float[] { 0, 1, 0 }, new float[] { 1, 0, 0, -1 }, new Net(new Span(1, 1), new Span(2, 1), new Span(0, 1), new Span(0, 0))),
+        new Face(new int[] { 1, 0, 3, 2 }, new float[] { 0, 0, -1 }, new float[] { 1, 0, 0, 1 }, new Net(new Span(0, 1), new Span(1, 1), new Span(0, 1), new Span(1, 1))),
+        new Face(new int[] { 4, 5, 6, 7 }, new float[] { 0, 0, 1 }, new float[] { -1, 0, 0, 1 }, new Net(new Span(1, 2), new Span(2, 2), new Span(0, 1), new Span(1, 1))),
+    };
+
+    private static int vao;
+    private static int vbo;
+
+    private UnitCubeMesh() {}
+
+    public static void write(long dst) {
+        long ptr = dst;
+        for (int f = 0; f < FACE_COUNT; f++) {
+            final Face face = FACES[f];
+            final Net net = face.net();
+            final float midUA = (net.uLow().a() + net.uHigh().a()) * 0.5f;
+            final float midUZ = (net.uLow().z() + net.uHigh().z()) * 0.5f;
+            final float midVA = (net.vLow().a() + net.vHigh().a()) * 0.5f;
+            final float midVZ = (net.vLow().z() + net.vHigh().z()) * 0.5f;
+            for (int c = 0; c < 4; c++) {
+                final float[] corner = CORNERS[face.corners()[c]];
+                final Span u = net.u(c);
+                final Span v = net.v(c);
+                memPutFloat(ptr + OFFSET_POSITION, corner[0]);
+                memPutFloat(ptr + OFFSET_POSITION + 4, corner[1]);
+                memPutFloat(ptr + OFFSET_POSITION + 8, corner[2]);
+                memPutInt(ptr + OFFSET_COLOR, 0xFFFFFFFF);
+                memPutFloat(ptr + OFFSET_MID, midUA);
+                memPutFloat(ptr + OFFSET_MID + 4, midUZ);
+                memPutFloat(ptr + OFFSET_MID + 8, midVA);
+                memPutFloat(ptr + OFFSET_MID + 12, midVZ);
+                memPutFloat(ptr + OFFSET_DELTA, u.a() - midUA);
+                memPutFloat(ptr + OFFSET_DELTA + 4, u.z() - midUZ);
+                memPutFloat(ptr + OFFSET_DELTA + 8, v.a() - midVA);
+                memPutFloat(ptr + OFFSET_DELTA + 12, v.z() - midVZ);
+                memPutFloat(ptr + OFFSET_NORMAL, face.normal()[0]);
+                memPutFloat(ptr + OFFSET_NORMAL + 4, face.normal()[1]);
+                memPutFloat(ptr + OFFSET_NORMAL + 8, face.normal()[2]);
+                final float[] tangent = face.tangent();
+                memPutInt(ptr + OFFSET_TANGENT, packTangent(tangent[0], tangent[1], tangent[2], tangent[3]));
+                ptr += VERTEX_STRIDE;
+            }
+        }
+    }
+
+    private static int packTangent(float x, float y, float z, float w) {
+        return NormI8.pack(x, y, z) | (((int) (w * 127.0f) & 0xFF) << 24);
+    }
+
+    public static int vao() {
+        if (vao == 0) build();
+        return vao;
+    }
+
+    private static void build() {
+        final int savedVAO = GLStateManager.getBoundVAO();
+        final int savedVBO = GLStateManager.getBoundVBO();
+        vao = GLStateManager.glGenVertexArrays();
+        GLStateManager.glBindVertexArray(vao);
+        vbo = GLStateManager.glGenBuffers();
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, vbo);
+
+        final int bytes = VERTEX_COUNT * VERTEX_STRIDE;
+        final ByteBuffer data = memAlloc(bytes);
+        try {
+            write(memAddress0(data));
+            data.position(0).limit(bytes);
+            GLStateManager.glBufferData(GL15.GL_ARRAY_BUFFER, data, GL15.GL_STATIC_DRAW);
+        } finally {
+            memFree(data);
+        }
+
+        attrib(VertexFormatElement.Usage.POSITION.getAttributeLocation(), 3, GL11.GL_FLOAT, false, OFFSET_POSITION);
+        attrib(VertexFormatElement.Usage.COLOR.getAttributeLocation(), 4, GL11.GL_UNSIGNED_BYTE, true, OFFSET_COLOR);
+        attrib(VertexFormatElement.Usage.PRIMARY_UV.getAttributeLocation(), 4, GL11.GL_FLOAT, false, OFFSET_MID);
+        attrib(VertexFormatElement.Usage.SECONDARY_UV.getAttributeLocation(), 4, GL11.GL_FLOAT, false, OFFSET_DELTA);
+        attrib(VertexFormatElement.Usage.NORMAL.getAttributeLocation(), 3, GL11.GL_FLOAT, false, OFFSET_NORMAL);
+        attrib(ImmediateExtendedAttribHandler.LOC_TANGENT, 4, GL11.GL_BYTE, true, OFFSET_TANGENT);
+
+        CubeInstancedAttribs.enableInstanceArrays();
+
+        GLStateManager.glBindVertexArray(savedVAO);
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, savedVBO);
+    }
+
+    private static void attrib(int loc, int size, int type, boolean normalized, int offset) {
+        GLStateManager.glEnableVertexAttribArray(loc);
+        GLStateManager.glVertexAttribPointer(loc, size, type, normalized, VERTEX_STRIDE, offset);
+    }
+
+    public static void delete() {
+        if (vbo != 0) {
+            GLStateManager.glDeleteBuffers(vbo);
+            vbo = 0;
+        }
+        if (vao != 0) {
+            GLStateManager.glDeleteVertexArrays(vao);
+            vao = 0;
+        }
+    }
+}

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

@@ -14,30 +14,34 @@ import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACK
 public final class VAOManager {
     public static final int MAX_ATTRIBS = 16;
 
-    public static final Int2ObjectOpenHashMap<VAOData> vaoMap = new Int2ObjectOpenHashMap<>();
+    public final Int2ObjectOpenHashMap<VAOData> vaoMap = new Int2ObjectOpenHashMap<>();
 
-    static final Int2ObjectOpenHashMap<VAOData> eboOwners = new Int2ObjectOpenHashMap<>();
+    final Int2ObjectOpenHashMap<VAOData> eboOwners = new Int2ObjectOpenHashMap<>();
 
-    private static VAOData current = null;
-    private static int currentVertexFlags = 0;
-    private static Attrib[] currentAttribs = null;
-    public static int boundEBO = 0;
+    private VAOData current = null;
+    private int currentVertexFlags = 0;
+    private Attrib[] currentAttribs = null;
+    public int boundEBO = 0;
 
-    private static int clientSideEnabledCount = 0;
+    private int clientSideEnabledCount = 0;
 
 
-    public static void init(int defaultVAO) {
+    public void init(int defaultVAO) {
         final VAOData data = new VAOData();
         current = data;
         currentAttribs = data.attribs;
         vaoMap.put(defaultVAO, data);
     }
 
-    public static void onBindEBO(int ebo) {
+    public boolean isInitialized() {
+        return current != null;
+    }
+
+    public void onBindEBO(int ebo) {
         boundEBO = ebo;
     }
 
-    public static void onBindVertexArrayPre(int vaoId) {
+    public void onBindVertexArrayPre(int vaoId) {
         // Save old VAO data
         if (current != null) {
             current.vertexFlags = currentVertexFlags;
@@ -62,14 +66,14 @@ public final class VAOManager {
         clientSideEnabledCount = data.clientSideEnabledCount;
     }
 
-    public static void onDeleteVertexArray(int vaoId) {
+    public void onDeleteVertexArray(int vaoId) {
         final VAOData data = vaoMap.remove(vaoId);
         if (data == null) return;
         removeEboOwner(data.ebo, data);
         if (data == current) current = null;
     }
 
-    public static void onDeleteBuffer(int buffer) {
+    public void onDeleteBuffer(int buffer) {
         if (buffer == 0) return;
         VAOData owner = eboOwners.remove(buffer);
         while (owner != null) {
@@ -80,12 +84,12 @@ public final class VAOManager {
         }
     }
 
-    private static void addEboOwner(int ebo, VAOData data) {
+    private void addEboOwner(int ebo, VAOData data) {
         if (ebo == 0) return;
         data.nextEboOwner = eboOwners.put(ebo, data);
     }
 
-    private static void removeEboOwner(int ebo, VAOData data) {
+    private void removeEboOwner(int ebo, VAOData data) {
         if (ebo == 0) return;
         VAOData node = eboOwners.get(ebo);
         if (node == data) {
@@ -105,10 +109,11 @@ public final class VAOManager {
         }
     }
 
-    public static void enableClientVertexFlag(int flag) { currentVertexFlags |= flag; }
-    public static void disableClientVertexFlag(int flag) { currentVertexFlags &= ~flag; }
-    public static int getCurrentVertexFlags() { return currentVertexFlags; }
-    public static void setCurrentVertexFlags(int flags) { currentVertexFlags = flags; }
+    public void enableClientVertexFlag(int flag) { currentVertexFlags |= flag; }
+    public void disableClientVertexFlag(int flag) { currentVertexFlags &= ~flag; }
+    public int getVertexFlags() { return currentVertexFlags; }
+    public void setVertexFlags(int flags) { currentVertexFlags = flags; }
+    public static void setCurrentVertexFlags(int flags) { GLStateManager.ctx().vaos.currentVertexFlags = flags; }
 
     public static final class VAOData {
         public Attrib[] attribs;
@@ -122,7 +127,7 @@ public final class VAOManager {
         }
     }
 
-    public static void setAttribute(int index, int size, int type, boolean normalized, int stride, long offset, int vboId) {
+    public void setAttribute(int index, int size, int type, boolean normalized, int stride, long offset, int vboId) {
         if (index < 0 || index >= MAX_ATTRIBS) return;
         final Attrib a = getAttrib(index);
         final boolean wasClient = a.clientPointer != null;
@@ -139,7 +144,7 @@ public final class VAOManager {
         }
     }
 
-    public static void setAttribute(int index, int size, int type, boolean normalized, int stride, ByteBuffer pointer) {
+    public void setAttribute(int index, int size, int type, boolean normalized, int stride, ByteBuffer pointer) {
         if (index < 0 || index >= MAX_ATTRIBS) return;
         final Attrib a = getAttrib(index);
         final boolean wasClient = a.clientPointer != null;
@@ -156,19 +161,19 @@ public final class VAOManager {
         }
     }
 
-    public static boolean isGenericPointerEnabled(int index) {
+    public boolean isGenericPointerEnabled(int index) {
         if (index < 0 || index >= MAX_ATTRIBS) return false;
         final Attrib a = currentAttribs[index];
         return a != null && a.genericPointer && a.enabled;
     }
 
-    public static void markConventional(int index) {
+    public void markConventional(int index) {
         if (index < 0 || index >= MAX_ATTRIBS) return;
         final Attrib a = currentAttribs[index];
         if (a != null) a.genericPointer = false;
     }
 
-    public static void setEnabled(int index, boolean enabled) {
+    public void setEnabled(int index, boolean enabled) {
         if (index < 0 || index >= MAX_ATTRIBS) return;
         final Attrib a = getAttrib(index);
         if (a.clientPointer != null && a.enabled != enabled) {
@@ -177,7 +182,7 @@ public final class VAOManager {
         a.enabled = enabled;
     }
 
-    public static void enableAttribute(int index) {
+    public void enableAttribute(int index) {
         if (index < 0 || index >= MAX_ATTRIBS) return;
         final Attrib a = getAttrib(index);
         if (a.clientPointer != null && !a.enabled) {
@@ -186,7 +191,7 @@ public final class VAOManager {
         a.enabled = true;
     }
 
-    public static void disableAttribute(int index) {
+    public void disableAttribute(int index) {
         if (index < 0 || index >= MAX_ATTRIBS) return;
         final Attrib a = getAttrib(index);
         if (a.clientPointer != null && a.enabled) {
@@ -196,7 +201,7 @@ public final class VAOManager {
     }
 
     // Lazily allocate each attrib. Most VAOs don't even have 4 attribs, let alone 16.
-    private static Attrib getAttrib(int index) {
+    private Attrib getAttrib(int index) {
         Attrib a = currentAttribs[index];
         if (a == null) {
             a = new Attrib();
@@ -205,28 +210,32 @@ public final class VAOManager {
         return a;
     }
 
-    public static boolean isClientSideAttrib(int index) {
+    public boolean isClientSideAttrib(int index) {
         final Attrib attrib = currentAttribs[index];
         return attrib != null && attrib.isClientSide();
     }
 
-    public static int getAttribEffectiveStride(int index) {
+    public Attrib attrib(int index) {
+        return currentAttribs[index];
+    }
+
+    public int attribEffectiveStride(int index) {
         final Attrib attrib = currentAttribs[index];
         return attrib != null ? attrib.effectiveStride() : 0;
     }
 
-    public static long getAttribOffset(int index) {
+    public long attribOffset(int index) {
         final Attrib attrib = currentAttribs[index];
         return attrib != null ? attrib.offset : 0;
     }
 
-    public static int getAttribVBO(int index) {
+    public int attribVBO(int index) {
         final Attrib attrib = currentAttribs[index];
         return attrib != null ? attrib.vboId : 0;
     }
 
     public static @Nullable Attrib get(int index) {
-        return currentAttribs[index];
+        return GLStateManager.ctx().vaos.attrib(index);
     }
 
 
@@ -236,7 +245,7 @@ public final class VAOManager {
      * (i.e. as a client-side pointer). In core profile, such attribs are treated as null
      * offsets into a non-existent buffer, causing a native crash at draw time.
      */
-    public static boolean hasAnyClientSideEnabledAttrib() {
+    public boolean hasAnyClientSideEnabledAttrib() {
         return clientSideEnabledCount > 0;
     }
 
@@ -244,15 +253,15 @@ public final class VAOManager {
      * If any enabled vertex attribute uses a client-side pointer (no VBO), upload all such
      * attribs into a shared stream VBO so the draw succeeds under core profile.
      */
-    private static int clientArraysVBO = 0;
-    private static int clientArraysVBOCapacity = 0;
-    private static final int[] clientArraysVBOOffsets = new int[VAOManager.MAX_ATTRIBS];
+    private int clientArraysVBO = 0;
+    private int clientArraysVBOCapacity = 0;
+    private final int[] clientArraysVBOOffsets = new int[VAOManager.MAX_ATTRIBS];
 
-    public static void uploadClientArraysToVBO() {
+    public void uploadClientArraysToVBO() {
         int totalBytes = 0;
         for (int i = 0; i < VAOManager.MAX_ATTRIBS; i++) {
             clientArraysVBOOffsets[i] = -1;
-            final VAOManager.Attrib a = VAOManager.get(i);
+            final VAOManager.Attrib a = currentAttribs[i];
             if (a == null || !a.enabled || a.clientPointer == null) continue;
             clientArraysVBOOffsets[i] = totalBytes;
             totalBytes += a.clientPointer.remaining();
@@ -275,7 +284,7 @@ public final class VAOManager {
 
         for (int i = 0; i < VAOManager.MAX_ATTRIBS; i++) {
             if (clientArraysVBOOffsets[i] < 0) continue;
-            final VAOManager.Attrib a = VAOManager.get(i);
+            final VAOManager.Attrib a = currentAttribs[i];
             RENDER_BACKEND.bufferSubData(GL15.GL_ARRAY_BUFFER, clientArraysVBOOffsets[i], a.clientPointer.duplicate());
             RENDER_BACKEND.vertexAttribPointer(i, a.size, a.type, a.normalized, a.stride, (long) clientArraysVBOOffsets[i]);
         }

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

@@ -2,6 +2,7 @@ package com.gtnewhorizons.angelica.glsm.ffp;
 
 import com.gtnewhorizon.gtnhlib.client.renderer.MatrixHelper;
 import com.gtnewhorizons.angelica.glsm.DisplayListManager;
+import com.gtnewhorizons.angelica.glsm.GLContextState;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.TexGenState;
 import com.gtnewhorizons.angelica.glsm.states.TextureUnitArray;
@@ -49,7 +50,14 @@ public final class VertexKey {
     private static final int BIT_UNIT_TEXMAT_BASE    = BIT_WIDE_LINE + 1;
     private static final int BIT_UNIT23_UV_FROM_UNIT0 = BIT_UNIT_TEXMAT_BASE + MAX_UNITS;
     private static final int BIT_LINE_STIPPLE        = BIT_UNIT23_UV_FROM_UNIT0 + 1;
-    private static final int BIT_INSTANCED           = BIT_LINE_STIPPLE + 1;
+    private static final int BIT_INSTANCING          = BIT_LINE_STIPPLE + 1;
+    private static final long INSTANCING_MASK        = 0x7L;
+
+    static {
+        if (Instancing.VALUES.length > INSTANCING_MASK + 1) {
+            throw new IllegalStateException("Instancing has outgrown the VertexKey field; widen INSTANCING_MASK");
+        }
+    }
 
     public static final int TG_NONE                  = 0;
     public static final int TG_OBJ_LINEAR            = 1;
@@ -97,7 +105,7 @@ public final class VertexKey {
     public boolean clipPlanesEnabled()    { return bit(BIT_CLIP_PLANES); }
     public boolean wideLineEmulation()   { return bit(BIT_WIDE_LINE); }
     public boolean lineStipple()          { return bit(BIT_LINE_STIPPLE); }
-    public boolean instancedDraw()       { return bit(BIT_INSTANCED); }
+    public Instancing instancing()         { return Instancing.VALUES[(int) ((packed >> BIT_INSTANCING) & INSTANCING_MASK)]; }
 
     public boolean cmReplacesAmbient()    { final int m = colorMaterialMode(); return m == CM_AMBIENT || m == CM_AMBIENT_AND_DIFFUSE; }
     public boolean cmReplacesDiffuse()    { final int m = colorMaterialMode(); return m == CM_DIFFUSE || m == CM_AMBIENT_AND_DIFFUSE; }
@@ -126,54 +134,66 @@ public final class VertexKey {
     }
 
     public static long packFromState(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap, int fragUnitMask) {
+        return packFromState(hasColor, hasNormal, hasTexCoord, hasLightmap, fragUnitMask, GLStateManager.ctx());
+    }
+
+    public static long packFromState(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap, int fragUnitMask, GLContextState glCtx) {
         long bits = 0;
 
-        final boolean lighting = GLStateManager.getLightingState().isEnabled();
+        final boolean lighting = glCtx.lightingState.isEnabled();
         if (lighting) {
             bits |= (1L << BIT_LIGHTING);
 
             for (int i = 0; i < FFP_LIGHT_COUNT; i++) {
-                if (!GLStateManager.getLightStates()[i].isEnabled()) continue;
+                if (!glCtx.lightStates[i].isEnabled()) continue;
                 bits |= (1L << (BIT_LIGHT_BASE + i));
                 // position.w == 0 means directional
-                if (GLStateManager.getLightDataStates()[i].position.w == 0.0f) {
+                if (glCtx.lightDataStates[i].position.w == 0.0f) {
                     bits |= (1L << (BIT_LIGHT_DIR_BASE + i));
                 }
             }
 
-            if (GLStateManager.getColorMaterial().isEnabled()) {
+            if (glCtx.colorMaterial.isEnabled()) {
                 bits |= (1L << BIT_COLOR_MATERIAL);
-                final int cmMode = encodeColorMaterialMode(GLStateManager.getColorMaterialParameter().getValue());
+                final int cmMode = encodeColorMaterialMode(glCtx.colorMaterialParameter.getValue());
                 bits |= ((long) cmMode & 0x7) << BIT_COLOR_MAT_MODE;
             }
 
-            if (GLStateManager.getLightModel().colorControl == GL12.GL_SEPARATE_SPECULAR_COLOR) {
+            if (glCtx.lightModel.colorControl == GL12.GL_SEPARATE_SPECULAR_COLOR) {
                 bits |= (1L << BIT_SEPARATE_SPECULAR);
             }
         }
 
-        if (GLStateManager.getFogMode().isEnabled()) {
+        if (glCtx.fogMode.isEnabled()) {
             bits |= (1L << BIT_FOG);
-            final int fogDistMode = GLStateManager.getFogState().getFogDistanceMode();
+            final int fogDistMode = glCtx.fogState.getFogDistanceMode();
             bits |= ((long) fogDistMode & 0x3) << BIT_FOG_DIST_MODE;
         }
 
-        if (GLStateManager.getNormalizeState().isEnabled()) {
+        if (glCtx.normalizeState.isEnabled()) {
             bits |= (1L << BIT_NORMALIZE);
         }
-        if (GLStateManager.getRescaleNormalState().isEnabled()) {
+        if (glCtx.rescaleNormalState.isEnabled()) {
             bits |= (1L << BIT_RESCALE_NORMAL);
         }
 
-        final TextureUnitArray texUnit = GLStateManager.getTextures();
+        final TextureUnitArray texUnit = glCtx.textures;
         for (int i = 0; i < MAX_UNITS; i++) {
             if ((fragUnitMask & (1 << i)) != 0) {
                 bits |= (1L << (BIT_UNIT_TEX_BASE + i));
             }
-            if (!MatrixHelper.isIdentity(texUnit.getTextureUnitMatrix(i))) {
-                bits |= (1L << (BIT_UNIT_TEXMAT_BASE + i));
-            }
         }
+        if (texUnit.texMatIdentityGen != glCtx.texMatrixGeneration) {
+            int mask = 0;
+            for (int i = 0; i < MAX_UNITS; i++) {
+                if (!MatrixHelper.isIdentity(texUnit.getTextureUnitMatrix(i))) {
+                    mask |= 1 << i;
+                }
+            }
+            texUnit.texMatIdentityMask = mask;
+            texUnit.texMatIdentityGen = glCtx.texMatrixGeneration;
+        }
+        bits |= ((long) texUnit.texMatIdentityMask) << BIT_UNIT_TEXMAT_BASE;
 
         // TexGen (unit 0 only) - per-coordinate mode if enabled.
         // TODO: per-unit texgen for units 2/3. Deferred - no MC code path uses glTexGen on those.
@@ -210,29 +230,31 @@ public final class VertexKey {
         if (hasTexCoord) bits |= (1L << BIT_HAS_VERTEX_TEX);
         if (hasLightmap) bits |= (1L << BIT_HAS_VERTEX_LIGHTMAP);
 
-        if (GLStateManager.consumeUnit23TexCoordSetDuringDraw() && hasTexCoord) {
+        if (GLStateManager.consumeUnit23TexCoordSetDuringDraw(glCtx) && hasTexCoord) {
             bits |= (1L << BIT_UNIT23_UV_FROM_UNIT0);
         }
 
-        if (GLStateManager.anyClipPlaneEnabled()) {
+        if (GLStateManager.anyClipPlaneEnabled(glCtx)) {
             bits |= (1L << BIT_CLIP_PLANES);
         }
 
-        if (GLStateManager.wideLineEmulationActive) {
+        if (glCtx.wideLineEmulationActive) {
             bits |= (1L << BIT_WIDE_LINE);
         }
 
-        if (GLStateManager.lineStippleActive) {
+        if (glCtx.lineStippleActive) {
             bits |= (1L << BIT_LINE_STIPPLE);
         }
 
-        if (GLStateManager.instancedFfpDrawActive) {
-            bits |= (1L << BIT_INSTANCED);
-        }
+        bits |= (long) glCtx.ffpInstancing.ordinal() << BIT_INSTANCING;
 
         return bits;
     }
 
+    static long withInstancing(long packed, Instancing kind) {
+        return (packed & ~(INSTANCING_MASK << BIT_INSTANCING)) | ((long) kind.ordinal() << BIT_INSTANCING);
+    }
+
     public static VertexKey fromState(boolean hasColor, boolean hasNormal, boolean hasTexCoord, boolean hasLightmap, int fragUnitMask) {
         return new VertexKey(packFromState(hasColor, hasNormal, hasTexCoord, hasLightmap, fragUnitMask));
     }
@@ -255,12 +277,6 @@ public final class VertexKey {
 
     @Override
     public String toString() {
-        return String.format("FFPVertexKey[0x%011X: lit=%b l0=%b l1=%b cm=%b fog=%b tex=%d%d%d%d texmat=%d%d%d%d col=%b nrm=%b vtex=%b vlm=%b tg=%d/%d/%d/%d clip=%b wline=%b inst=%b]",
-            packed, lightingEnabled(), lightEnabled(0), lightEnabled(1),
-            colorMaterialEnabled(), fogEnabled(),
-            unitTexCoordEnabled(0)?1:0, unitTexCoordEnabled(1)?1:0, unitTexCoordEnabled(2)?1:0, unitTexCoordEnabled(3)?1:0,
-            unitTexMatEnabled(0)?1:0, unitTexMatEnabled(1)?1:0, unitTexMatEnabled(2)?1:0, unitTexMatEnabled(3)?1:0,
-            hasVertexColor(), hasVertexNormal(), hasVertexTexCoord(), hasVertexLightmap(),
-            texGenModeS(), texGenModeT(), texGenModeR(), texGenModeQ(), clipPlanesEnabled(), wideLineEmulation(), instancedDraw());
+        return String.format("FFPVertexKey[0x%011X: lit=%b l0=%b l1=%b cm=%b fog=%b tex=%d%d%d%d texmat=%d%d%d%d col=%b nrm=%b vtex=%b vlm=%b tg=%d/%d/%d/%d clip=%b wline=%b inst=%s]", packed,lightingEnabled(), lightEnabled(0), lightEnabled(1), colorMaterialEnabled(), fogEnabled(), unitTexCoordEnabled(0)?1:0, unitTexCoordEnabled(1)?1:0, unitTexCoordEnabled(2)?1:0, unitTexCoordEnabled(3)?1:0, unitTexMatEnabled(0)?1:0, unitTexMatEnabled(1)?1:0, unitTexMatEnabled(2)?1:0, unitTexMatEnabled(3)?1:0, hasVertexColor(), hasVertexNormal(), hasVertexTexCoord(), hasVertexLightmap(), texGenModeS(), texGenModeT(), texGenModeR(), texGenModeQ(), clipPlanesEnabled(), wideLineEmulation(), instancing());
     }
 }

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

@@ -21,6 +21,10 @@ public final class VertexShaderGenerator {
         emitOutputs(sb, key);
 
         sb.append("void main() {\n");
+        if (key.instancing() == Instancing.WEATHER) {
+            sb.append("  ").append(InstancedGlslHelpers.weatherPrologue("u_", "a_", "a_TexCoord0",
+                "vec4 weatherVertex", "vec4 weatherColor", "vec4 weatherTex0", "vec4 weatherTex1", "\n  ")).append('\n');
+        }
         emitPositionTransform(sb, key);
         if (key.lightingEnabled()) {
             emitNormalTransform(sb, key);
@@ -55,31 +59,44 @@ public final class VertexShaderGenerator {
     }
 
     private static void emitAttributes(StringBuilder sb, VertexKey key) {
+        final Instancing kind = key.instancing();
         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()) {
+        if (kind == Instancing.PARTICLE || kind == Instancing.WEATHER) {
             sb.append("layout(location = ").append(VertexFormatElement.Usage.PRIMARY_UV.getAttributeLocation()).append(") in vec2 a_TexCoord0;\n");
+        } else {
+            if (key.hasVertexColor()) {
+                sb.append("layout(location = ").append(VertexFormatElement.Usage.COLOR.getAttributeLocation()).append(") in vec4 a_Color;\n");
+            }
+            if (kind != Instancing.CUBE) {
+                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() || kind == Instancing.CUBE) {
+                sb.append("layout(location = ").append(VertexFormatElement.Usage.NORMAL.getAttributeLocation()).append(") in vec3 a_Normal;\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");
-        }
-        if (key.instancedDraw()) {
-            sb.append("layout(location = ").append(InstancedAttribs.LOC_MATRIX_COL0).append(") in vec4 a_InstCol0;\n");
-            sb.append("layout(location = ").append(InstancedAttribs.LOC_MATRIX_COL1).append(") in vec4 a_InstCol1;\n");
-            sb.append("layout(location = ").append(InstancedAttribs.LOC_MATRIX_COL2).append(") in vec4 a_InstCol2;\n");
-            sb.append("layout(location = ").append(InstancedAttribs.LOC_MATRIX_COL3).append(") in vec4 a_InstCol3;\n");
-            sb.append("layout(location = ").append(InstancedAttribs.LOC_COLOR).append(") in vec4 a_InstColor;\n");
-            sb.append("layout(location = ").append(InstancedAttribs.LOC_LIGHTMAP).append(") in vec2 a_InstLightmap;\n");
+        for (String d : InstancedGlslHelpers.attributeDecls("a_", kind)) {
+            sb.append(d).append('\n');
         }
         sb.append('\n');
     }
 
+    private static final String PARTICLE_UV = InstancedGlslHelpers.particleUv("a_InstUv", "a_TexCoord0");
+
+    private static String unit0Source(VertexKey key) {
+        return switch (key.instancing()) {
+            case CUBE -> "cubeUv";
+            case PARTICLE -> PARTICLE_UV;
+            case WEATHER -> "weatherTex0";
+            case NONE, TEMPLATE -> key.hasVertexTexCoord() ? "vec4(a_TexCoord0, 0.0, 1.0)" : "u_CurrentTexCoord0";
+        };
+    }
+
     private static void emitLineStart(StringBuilder sb) {
         sb.append("  vec2 ndc = gl_Position.xy / gl_Position.w;\n");
         sb.append("  v_LineStart = u_Viewport.xy + (ndc * 0.5 + 0.5) * u_Viewport.zw;\n\n");
@@ -93,6 +110,10 @@ public final class VertexShaderGenerator {
     private static void emitOutputs(StringBuilder sb, VertexKey key) {
         sb.append("// Outputs\n");
         sb.append("out vec4 v_Color;\n");
+        if (key.instancing().hasInstanceHead()) {
+            sb.append("out vec4 v_Overlay;\n");
+            sb.append("invariant gl_Position;\n");
+        }
         if (key.lineStipple()) {
             sb.append("flat out vec2 v_LineStart;\n");
         }
@@ -116,11 +137,18 @@ public final class VertexShaderGenerator {
 
     private static void emitPositionTransform(StringBuilder sb, VertexKey key) {
         sb.append("  // Position transform\n");
-        sb.append("  vec4 pos4 = vec4(a_Position, 1.0);\n");
-        if (key.instancedDraw()) {
-            sb.append("  mat4 instMV = mat4(a_InstCol0, a_InstCol1, a_InstCol2, a_InstCol3);\n");
+        if (key.instancing() == Instancing.PARTICLE) {
+            sb.append("  vec4 pos4 = ").append(InstancedGlslHelpers.particlePos("a_InstCenterHalf", "a_Position")).append(";\n");
+        } else if (key.instancing() == Instancing.WEATHER) {
+            sb.append("  vec4 pos4 = weatherVertex;\n");
+        } else {
+            sb.append("  vec4 pos4 = vec4(a_Position, 1.0);\n");
+        }
+        if (key.instancing().hasInstanceHead()) {
+            sb.append("  mat4 instMV = ").append(InstancedGlslHelpers.mat4FromRows("a_InstRow0", "a_InstRow1", "a_InstRow2")).append(";\n");
             sb.append("  vec4 eyePos = instMV * pos4;\n");
             sb.append("  gl_Position = u_ProjectionMatrix * eyePos;\n");
+            sb.append("  v_Overlay = a_InstOverlay;\n");
         } else {
             sb.append("  gl_Position = u_MVPMatrix * pos4;\n");
 
@@ -134,8 +162,8 @@ public final class VertexShaderGenerator {
 
     private static void emitNormalTransform(StringBuilder sb, VertexKey key) {
         sb.append("  // Normal transform\n");
-        final String srcNormal = key.hasVertexNormal() ? "a_Normal" : "u_CurrentNormal";
-        if (key.instancedDraw()) {
+        final String srcNormal = key.hasVertexNormal() && key.instancing() != Instancing.PARTICLE ? "a_Normal" : "u_CurrentNormal";
+        if (key.instancing().hasInstanceHead()) {
             sb.append("  vec3 normal = normalize(mat3(instMV) * ").append(srcNormal).append(");\n");
             sb.append('\n');
             return;
@@ -156,9 +184,13 @@ public final class VertexShaderGenerator {
         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");
-            if (key.instancedDraw()) {
-                sb.append(" * a_InstColor");
+            if (key.instancing() == Instancing.PARTICLE) {
+                sb.append("a_InstColor");
+            } else {
+                sb.append(key.hasVertexColor() ? "a_Color" : "u_CurrentColor");
+                if (key.instancing().hasInstanceHead()) {
+                    sb.append(" * a_InstColor");
+                }
             }
             sb.append(";\n");
 
@@ -255,22 +287,28 @@ public final class VertexShaderGenerator {
     private static void emitColorPassthrough(StringBuilder sb, VertexKey key) {
         sb.append("  // Color passthrough (no lighting)\n");
         final String src = key.hasVertexColor() ? "a_Color" : "u_CurrentColor";
-        if (key.instancedDraw()) {
-            sb.append("  v_Color = ").append(src).append(" * a_InstColor;\n");
-        } else {
-            sb.append("  v_Color = ").append(src).append(";\n");
+        switch (key.instancing()) {
+            case PARTICLE -> sb.append("  v_Color = a_InstColor;\n");
+            case WEATHER -> sb.append("  v_Color = weatherColor;\n");
+            case TEMPLATE, CUBE -> sb.append("  v_Color = ").append(src).append(" * a_InstColor;\n");
+            case NONE -> sb.append("  v_Color = ").append(src).append(";\n");
         }
         sb.append('\n');
     }
 
     private static void emitTexCoordPassthrough(StringBuilder sb, VertexKey key) {
+        final boolean cube = key.instancing() == Instancing.CUBE;
+        final boolean unit0FromCube = cube && key.unitTexCoordEnabled(0) && !key.texGenEnabled();
+        final boolean unit23FromCube = cube && key.unit23UvFromUnit0() && (key.unitTexCoordEnabled(2) || key.unitTexCoordEnabled(3));
+        if (unit0FromCube || unit23FromCube) {
+            emitCubeTexCoord(sb);
+        }
+
         if (key.texGenEnabled()) {
             emitTexGenCoordGeneration(sb, key);
         } else if (key.unitTexCoordEnabled(0)) {
             sb.append("  // Texture coordinates - unit 0\n");
-            final String src = key.hasVertexTexCoord()
-                ? "vec4(a_TexCoord0, 0.0, 1.0)"
-                : "u_CurrentTexCoord0";
+            final String src = unit0Source(key);
             if (key.unitTexMatEnabled(0)) {
                 sb.append("  v_TexCoord0 = u_TextureMatrix0 * ").append(src).append(";\n");
             } else {
@@ -279,20 +317,18 @@ public final class VertexShaderGenerator {
         }
 
         if (key.lightmapEnabled()) {
-            if (key.instancedDraw()) {
-                sb.append("  v_TexCoord1 = u_LightmapTextureMatrix * vec4(a_InstLightmap, 0.0, 1.0);\n");
-            } else 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");
-            }
+            final String lightmap = switch (key.instancing()) {
+                case PARTICLE, TEMPLATE -> "a_InstLightmap";
+                case CUBE -> "a_InstLightmapScale.xy";
+                case WEATHER -> "weatherTex1.xy";
+                case NONE -> key.hasVertexLightmap() ? "a_TexCoord1" : "u_CurrentLightmapCoord";
+            };
+            sb.append("  v_TexCoord1 = u_LightmapTextureMatrix * vec4(").append(lightmap).append(", 0.0, 1.0);\n");
         }
 
         for (int i = 2; i < VertexKey.MAX_UNITS; i++) {
             if (!key.unitTexCoordEnabled(i)) continue;
-            final String src = key.unit23UvFromUnit0()
-                ? "vec4(a_TexCoord0, 0.0, 1.0)"
-                : "u_CurrentTexCoord" + i;
+            final String src = key.unit23UvFromUnit0() ? unit0Source(key) : "u_CurrentTexCoord" + i;
             if (!key.unit23UvFromUnit0() && key.unitTexMatEnabled(i)) {
                 sb.append("  v_TexCoord").append(i).append(" = u_TextureMatrix").append(i).append(" * ").append(src).append(";\n");
             } else {
@@ -301,6 +337,12 @@ public final class VertexShaderGenerator {
         }
     }
 
+    private static void emitCubeTexCoord(StringBuilder sb) {
+        sb.append("  // Cube texture net\n");
+        sb.append("  ").append(InstancedGlslHelpers.cubePrelude("", "a_CubeMid", "a_CubeDelta", "a_Normal", "a_CubeTex", "\n  ")).append('\n');
+        sb.append("  vec4 cubeUv = ").append(InstancedGlslHelpers.cubeUv("a_CubeTex", "a_InstLightmapScale", "cubeU.x", "cubeU.y", "cubeV.x", "cubeV.y")).append(";\n\n");
+    }
+
     /**
      * Emit per-coordinate texgen code following Mesa's ffvertex_prog.c build order.
      * OBJ_LINEAR: dot(pos4, objPlane), EYE_LINEAR: dot(eyePos, eyePlane).

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

@@ -0,0 +1,34 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.lwjgl.opengl.GL11;
+
+
+/**
+ * One rain or snow column per instance.
+ */
+public final class WeatherInstancedAttribs {
+
+    public static final int LOC_COLUMN_SPAN = ParticleInstancedAttribs.LOC_CENTER_HALF;
+    public static final int LOC_JITTER = ParticleInstancedAttribs.LOC_UV;
+    public static final int LOC_PARAMS = InstancedAttribs.LOC_COLOR;
+
+    public static final int OFFSET_COLUMN_SPAN = 0;
+    public static final int OFFSET_JITTER = 16;
+    public static final int OFFSET_PARAMS = 32;
+    public static final int STRIDE = 48;
+
+    public static void pointInstanceAttribs(long base) {
+        GLStateManager.glVertexAttribPointer(LOC_COLUMN_SPAN, 4, GL11.GL_FLOAT, false, STRIDE, base + OFFSET_COLUMN_SPAN);
+        GLStateManager.glVertexAttribPointer(LOC_JITTER, 4, GL11.GL_FLOAT, false, STRIDE, base + OFFSET_JITTER);
+        GLStateManager.glVertexAttribPointer(LOC_PARAMS, 4, GL11.GL_FLOAT, false, STRIDE, base + OFFSET_PARAMS);
+    }
+
+    static void enableInstanceArrays() {
+        InstancedAttribs.enableInstanced(LOC_COLUMN_SPAN);
+        InstancedAttribs.enableInstanced(LOC_JITTER);
+        InstancedAttribs.enableInstanced(LOC_PARAMS);
+    }
+
+    private WeatherInstancedAttribs() {}
+}

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

@@ -0,0 +1,42 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+/**
+ * The per-frame half of the rain and snow instancing, set once per weather draw.
+ */
+public final class WeatherParams {
+
+    public static float translateX;
+    public static float translateY;
+    public static float translateZ;
+    public static float invRadius;
+
+    public static float cameraFracX;
+    public static float cameraFracZ;
+    public static float partialTicks;
+    public static float age;
+
+    public static float rainScroll;
+    public static float snowScroll;
+    public static float rainStrength;
+
+    public static int generation;
+
+    private WeatherParams() {}
+
+    public static void set(float translateX, float translateY, float translateZ, float invRadius,
+        float cameraFracX, float cameraFracZ, float partialTicks, float age,
+        float rainScroll, float snowScroll, float rainStrength) {
+        WeatherParams.translateX = translateX;
+        WeatherParams.translateY = translateY;
+        WeatherParams.translateZ = translateZ;
+        WeatherParams.invRadius = invRadius;
+        WeatherParams.cameraFracX = cameraFracX;
+        WeatherParams.cameraFracZ = cameraFracZ;
+        WeatherParams.partialTicks = partialTicks;
+        WeatherParams.age = age;
+        WeatherParams.rainScroll = rainScroll;
+        WeatherParams.snowScroll = snowScroll;
+        WeatherParams.rainStrength = rainStrength;
+        generation++;
+    }
+}

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

@@ -0,0 +1,69 @@
+package com.gtnewhorizons.angelica.glsm.ffp;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+
+/**
+ * The four corners every rain and snow column is expanded from. x picks the end of the billboard, y picks
+ * the bottom or top edge.
+ */
+public final class WeatherQuadMesh {
+
+    public static final int VERTEX_FLAGS = VertexFlags.TEXTURE_BIT;
+    public static final int VERTEX_COUNT = 4;
+
+    private static final float[] CORNERS = { 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f };
+
+    private static int vao;
+    private static int vbo;
+
+    private WeatherQuadMesh() {}
+
+    public static int vao() {
+        if (vao != 0) return vao;
+
+        final ByteBuffer data = ByteBuffer.allocateDirect(CORNERS.length * Float.BYTES).order(ByteOrder.nativeOrder());
+        for (float corner : CORNERS) data.putFloat(corner);
+        data.flip();
+
+        vao = GLStateManager.glGenVertexArrays();
+        GLStateManager.glBindVertexArray(vao);
+        vbo = GLStateManager.glGenBuffers();
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, vbo);
+        GLStateManager.glBufferData(GL15.GL_ARRAY_BUFFER, data, GL15.GL_STATIC_DRAW);
+
+        final int corner = VertexFormatElement.Usage.PRIMARY_UV.getAttributeLocation();
+        GLStateManager.glEnableVertexAttribArray(corner);
+        GLStateManager.glVertexAttribPointer(corner, 2, GL11.GL_FLOAT, false, 2 * Float.BYTES, 0L);
+        WeatherInstancedAttribs.enableInstanceArrays();
+
+        GLStateManager.glBindVertexArray(0);
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);
+        return vao;
+    }
+
+    public static void bindInstanceBuffer(int bufferId) {
+        GLStateManager.glBindVertexArray(vao());
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, bufferId);
+        WeatherInstancedAttribs.pointInstanceAttribs(0L);
+        GLStateManager.glBindVertexArray(0);
+        GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);
+    }
+
+    public static void delete() {
+        if (vbo != 0) {
+            GLStateManager.glDeleteBuffers(vbo);
+            vbo = 0;
+        }
+        if (vao != 0) {
+            GLStateManager.glDeleteVertexArrays(vao);
+            vao = 0;
+        }
+    }
+}

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

@@ -2,6 +2,6 @@ package com.gtnewhorizons.angelica.glsm.hooks;
 
 public interface DeferredAlphaHandler {
     boolean isAlphaTestLocked();
-    void deferAlphaTestToggle(boolean enabled);
-    void deferAlphaFunc(int function, float reference);
+    boolean deferAlphaTestToggle(boolean enabled);
+    boolean deferAlphaFunc(int function, float reference);
 }

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

@@ -41,10 +41,6 @@ public final class FrameHooks {
         BackendManager.shutdown();
     }
 
-    public static void bindSplashVao() {
-        GLStateManager.glBindVertexArray(GLStateManager.glGenVertexArrays());
-    }
-
     public static void splashFinished() {
         GLStateManager.markSplashComplete("SplashProgress.finish");
     }

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

@@ -1,17 +1,17 @@
 package com.gtnewhorizons.angelica.glsm.hooks;
 
-public final class GLSMConfig {
+import com.gtnewhorizons.angelica.glsm.GLContextState;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
 
-    // Lightmap (replaces OpenGlHelper.lastBrightnessX/Y)
-    public static float lastBrightnessX;
-    public static float lastBrightnessY;
+public final class GLSMConfig {
 
     public static int packBrightness(float x, float y) {
         return ((int) y << 16) | ((int) x & 0xFFFF);
     }
 
     public static int packedLastBrightness() {
-        return packBrightness(lastBrightnessX, lastBrightnessY);
+        final GLContextState glCtx = GLStateManager.ctx();
+        return packBrightness(glCtx.lastBrightnessX, glCtx.lastBrightnessY);
     }
 
     public static boolean hudCacheOverride;

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

@@ -1,5 +1,6 @@
 package com.gtnewhorizons.angelica.glsm.hooks;
 
+import com.gtnewhorizons.angelica.glsm.DisplayListManager;
 import com.gtnewhorizons.angelica.glsm.hooks.events.*;
 import net.minecraftforge.eventbus.api.bus.EventBus;
 
@@ -14,6 +15,12 @@ public final class GLSMHooks {
     public static ShaderTransformPostProcessor postTransformProcessor;
     public static PerFrameUniformBlock perFrameUniformBlock;
     public static PerFrameUniformBlock perPassUniformBlock;
+    public static PendingProgramSelection pendingProgramSelection;
+
+    public static void resolvePendingProgram() {
+        final PendingProgramSelection p = pendingProgramSelection;
+        if (p != null && !DisplayListManager.isRecording()) p.resolvePendingProgram();
+    }
 
     // EventBus instances
     public static final EventBus<TextureBindEvent> TEXTURE_BIND = EventBus.create(TextureBindEvent.class);

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

@@ -12,7 +12,6 @@ public final class GLSMInitConfig {
     @Getter private final boolean lwjglDebug;
     @Getter private final StreamingUploader.UploadStrategy streamingUploadStrategy;
     @Getter private final Consumer<DirectTessellator> directDrawer;
-    @Getter private final Runnable streamingDrawerDestroy;
     @Getter private final int displayWidth;
     @Getter private final int displayHeight;
     @Getter private final Runnable postInitCallback;
@@ -24,7 +23,6 @@ public final class GLSMInitConfig {
         this.streamingUploadStrategy = builder.streamingUploadStrategy;
         this.noErrorChecks = builder.noErrorChecks;
         this.directDrawer = builder.directDrawer;
-        this.streamingDrawerDestroy = builder.streamingDrawerDestroy;
         this.displayWidth = builder.displayWidth;
         this.displayHeight = builder.displayHeight;
         this.postInitCallback = builder.postInitCallback;
@@ -43,7 +41,6 @@ public final class GLSMInitConfig {
         private boolean lwjglDebug = SystemProperties.LWJGL_DEBUG;
         private StreamingUploader.UploadStrategy streamingUploadStrategy = StreamingUploader.UploadStrategy.BUFFER_DATA;
         private Consumer<DirectTessellator> directDrawer = TessellatorStreamingDrawer::drawDirect;
-        private Runnable streamingDrawerDestroy = TessellatorStreamingDrawer::destroy;
         private int displayWidth = 0;
         private int displayHeight = 0;
         private Runnable postInitCallback = null;
@@ -72,11 +69,6 @@ public final class GLSMInitConfig {
             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;

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

@@ -0,0 +1,5 @@
+package com.gtnewhorizons.angelica.glsm.hooks;
+
+public interface PendingProgramSelection {
+    void resolvePendingProgram();
+}

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

@@ -11,22 +11,20 @@ public final class TextureUtilHooks {
 
     private TextureUtilHooks() {}
 
-    private static int savedFilterTextureId;
-
     public static void setMaxLevel(int mipmapLevels) {
         GLStateManager.glTexParameteri(GL11.GL_TEXTURE_2D, GL12.GL_TEXTURE_MAX_LEVEL, mipmapLevels);
     }
 
     public static void captureBoundFilterTexture() {
-        savedFilterTextureId = GLStateManager.getBoundTextureForServerState();
+        GLStateManager.ctx().savedFilterTextureId = GLStateManager.getBoundTextureForServerState();
     }
 
     public static void clearSavedFilterTexture() {
-        savedFilterTextureId = 0;
+        GLStateManager.ctx().savedFilterTextureId = 0;
     }
 
     public static void restoreFilter(int min, int mag) {
-        final int id = savedFilterTextureId;
+        final int id = GLStateManager.ctx().savedFilterTextureId;
         if (id != 0 && DisplayListManager.getRecordMode() == DisplayListManager.RecordMode.NONE) {
             RenderSystem.texParameteri(id, GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, min);
             RenderSystem.texParameteri(id, GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, mag);
@@ -37,7 +35,7 @@ public final class TextureUtilHooks {
     }
 
     public static void restoreAniso(float aniso) {
-        final int id = savedFilterTextureId;
+        final int id = GLStateManager.ctx().savedFilterTextureId;
         if (id != 0 && DisplayListManager.getRecordMode() == DisplayListManager.RecordMode.NONE) {
             RenderSystem.texParameterf(id, GL11.GL_TEXTURE_2D, EXTTextureFilterAnisotropic.GL_TEXTURE_MAX_ANISOTROPY_EXT, aniso);
         } else {

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

@@ -21,6 +21,7 @@ public final class ClassDump {
 
     public void dumpRFBClass(String className, ClassNodeHandle classNode, Object transformer) {
         if (!enabled) return;
+        classNode.markDirty();
         dumpClass(className, classNode.getOriginalBytes(), classNode.computeBytes(), transformer);
     }
 }

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

@@ -30,11 +30,20 @@ public final class DependencyVerifier {
      * @param checks  Dependency checks to run
      */
     public static void verify(Class<?> anchor, List<Check> checks) {
+        final Check missing = firstMissing(anchor, checks);
+        if (missing != null) {
+            throw new RuntimeException(missing.errorMessage());
+        }
+    }
+
+    /** @return the first check whose resource is absent, or null when all pass. */
+    public static Check firstMissing(Class<?> anchor, List<Check> checks) {
         for (Check check : checks) {
             if (anchor.getResource(check.resourcePath()) == null) {
-                throw new RuntimeException(check.errorMessage());
+                return check;
             }
         }
+        return null;
     }
 
     public static List<Check> gtnhLibChecks(String productName) {

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

@@ -68,6 +68,7 @@ public final class AttribSnapshot {
         final AttribDesc[] out = new AttribDesc[VAOManager.MAX_ATTRIBS];
         final List<ByteBuffer> allocated = new ArrayList<>();
         final int prevVBO = GLStateManager.getBoundVBO();
+        final VAOManager vaos = GLStateManager.ctx().vaos;
         boolean success = false;
 
         // Pass 1 — unioned [start,end] per vboId. Hot path: one source VBO, zero allocations.
@@ -78,7 +79,7 @@ public final class AttribSnapshot {
 
         final long lastVtx = (long) firstVertex + vertexCount - 1;
         for (int i = 0; i < VAOManager.MAX_ATTRIBS; i++) {
-            final VAOManager.Attrib a = VAOManager.get(i);
+            final VAOManager.Attrib a = vaos.attrib(i);
             if (a == null || !a.enabled || a.vboId == 0) continue;
             final int stride = a.effectiveStride();
             final long typeBytes = (long) a.size * GLTypes.sizeBytes(a.type);
@@ -114,7 +115,7 @@ public final class AttribSnapshot {
 
         try {
             for (int i = 0; i < VAOManager.MAX_ATTRIBS; i++) {
-                final VAOManager.Attrib a = VAOManager.get(i);
+                final VAOManager.Attrib a = vaos.attrib(i);
                 if (a == null || !a.enabled) continue;
 
                 if (a.vboId != 0) {

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

@@ -810,6 +810,8 @@ public class GLSMRedirector {
             .add("gluBuild2DMipmaps")
             .add("gluErrorString")
         );
+        // Must honor disableErrorChecks like glGetError, or it throws on errors those checks left latched
+        methodRedirects.put("org/lwjgl/opengl/Util", RedirectMap.newMap().add("checkGLError"));
 
         // Quadric type replacements
         typeRedirects.put("org/lwjgl/util/glu/Sphere", "com/gtnewhorizons/angelica/glsm/compat/lwjgl/AngelicaSphere");

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

@@ -1,45 +1,46 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.hooks.VanillaStateLayer;
 import com.gtnewhorizons.angelica.glsm.states.AlphaState;
 import lombok.Setter;
 
-public class AlphaStateStack extends AlphaState implements IStateStack<AlphaState> {
+public final class AlphaStateStack extends AlphaState implements CowStateStack<AlphaStateStack> {
 
     protected final AlphaState[] stack;
-
-    protected int pointer;
+    private final CowDepths cow = new CowDepths();
 
     @Setter private VanillaStateLayer<AlphaState> vanillaLayer;
 
-    public AlphaStateStack() {
+    public AlphaStateStack(int id) {
+        cow.id = id;
         stack = new AlphaState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new AlphaState();
         }
     }
 
-    public AlphaStateStack push() {
-        if(pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        VanillaStateLayer.capture(vanillaLayer, stack[pointer++].set(this));
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public AlphaStateStack pop() {
-        if(pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
+    @Override
+    public void captureSlot(int s) {
+        VanillaStateLayer.capture(vanillaLayer, stack[s].set(this));
+    }
 
-        final AlphaState saved = stack[--pointer];
+    @Override
+    public void restoreSlot(int s) {
+        final AlphaState saved = stack[s];
         if (!VanillaStateLayer.restore(vanillaLayer, saved)) {
             set(saved);
         }
-        return this;
+    }
+
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
     }
 
     public AlphaState readEffective(AlphaState out) {
@@ -48,7 +49,8 @@ public class AlphaStateStack extends AlphaState implements IStateStack<AlphaStat
         return out;
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,49 +1,51 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.StateSet;
 import com.gtnewhorizons.angelica.glsm.hooks.VanillaStateLayer;
 import com.gtnewhorizons.angelica.glsm.states.BlendState;
 import lombok.Setter;
 
-public class BlendStateStack extends BlendState implements IStateStack<BlendStateStack> {
+public final class BlendStateStack extends BlendState implements CowStateStack<BlendStateStack> {
 
     protected final BlendState[] stack;
-
-    protected int pointer;
+    private final CowDepths cow = new CowDepths(StateSet.R_BLEND);
 
     private boolean funcUnknown;
 
     @Setter private VanillaStateLayer<BlendState> vanillaLayer;
 
-    public BlendStateStack() {
+    public BlendStateStack(int id) {
+        cow.id = id;
         stack = new BlendState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new BlendState();
         }
     }
 
-    public BlendStateStack push() {
-        if(pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        VanillaStateLayer.capture(vanillaLayer, stack[pointer++].set(this));
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public BlendStateStack pop() {
-        if(pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
+    @Override
+    public void captureSlot(int s) {
+        VanillaStateLayer.capture(vanillaLayer, stack[s].set(this));
+    }
 
-        final BlendState saved = stack[--pointer];
+    @Override
+    public void restoreSlot(int s) {
+        final BlendState saved = stack[s];
         if (VanillaStateLayer.restore(vanillaLayer, saved)) {
             setExceptFunc(saved);
         } else {
             set(saved);
         }
-        return this;
+    }
+
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
     }
 
     public void setFuncUnknownState() {
@@ -64,11 +66,8 @@ public class BlendStateStack extends BlendState implements IStateStack<BlendStat
         return out;
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
-    }
-
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,6 +1,6 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
+import com.gtnewhorizons.angelica.glsm.GLContextState;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.hooks.VanillaBooleanLayer;
 import com.gtnewhorizons.angelica.glsm.states.BooleanState;
@@ -13,17 +13,12 @@ import lombok.Setter;
  * saved when actually modified, dramatically reducing overhead when most states
  * don't change (e.g., GL_ENABLE_BIT saves ~270 states but typically only 3-4 change).
  */
-public class BooleanStateStack extends BooleanState implements IStateStack<BooleanStateStack> {
+public class BooleanStateStack extends BooleanState implements CowStateStack<BooleanStateStack> {
 
     protected final boolean[] stack;
+    private final CowDepths cow = new CowDepths();
     @Setter private VanillaBooleanLayer vanillaLayer;
 
-    /**
-     * The depth at which state has been saved. Compared against GLStateManager.getAttribDepth()
-     * to determine if we need to save before modification or restore on pop.
-     */
-    protected int savedDepth;
-
     public BooleanStateStack(int glCap) {
         this(glCap, false, false);
     }
@@ -52,24 +47,24 @@ public class BooleanStateStack extends BooleanState implements IStateStack<Boole
         stack = new boolean[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
     }
 
-    // ==================== Traditional Stack Operations ====================
-
     @Override
-    public BooleanStateStack push() {
-        if (savedDepth >= stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (savedDepth + 1) + " reached");
-        }
-        stack[savedDepth++] = vanillaValue();
-        return this;
+    public CowDepths cowDepths() {
+        return cow;
     }
 
     @Override
-    public BooleanStateStack pop() {
-        if (savedDepth == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-        restore(stack[--savedDepth]);
-        return this;
+    public void captureSlot(int slot) {
+        stack[slot] = vanillaValue();
+    }
+
+    @Override
+    public void restoreSlot(int slot) {
+        restore(stack[slot]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 
     public boolean isEffectivelyEnabled() {
@@ -88,45 +83,6 @@ public class BooleanStateStack extends BooleanState implements IStateStack<Boole
         }
     }
 
-    @Override
-    public boolean isEmpty() {
-        return savedDepth == 0;
-    }
-
-    // ==================== Lazy Copy-on-Write Operations ====================
-
-    @Override
-    public int pushDepth() {
-        // No-op: global depth is managed by GLStateManager
-        return GLStateManager.getAttribDepth();
-    }
-
-    /**
-     * Restore state if it was modified at the current depth.
-     * Only called by GLStateManager.popState() for states that registered as modified.
-     */
-    @Override
-    public BooleanStateStack popDepth() {
-        // We're only called if we were modified, so savedDepth should match
-        if (savedDepth > 0) {
-            restore(stack[--savedDepth]);
-        }
-        return this;
-    }
-
-    /**
-     * Called before modifying state. If we haven't saved at the current depth yet,
-     * save the current value and register with GLStateManager for restoration.
-     */
-    @Override
-    public void beforeModify() {
-        final int globalDepth = GLStateManager.getAttribDepth();
-        if (savedDepth < globalDepth) {
-            stack[savedDepth++] = vanillaValue();
-            GLStateManager.registerModifiedState(this);
-        }
-    }
-
     @Override
     public int getDepth() {
         return GLStateManager.getAttribDepth();
@@ -134,7 +90,11 @@ public class BooleanStateStack extends BooleanState implements IStateStack<Boole
 
     @Override
     public void setEnabled(boolean enabled) {
-        beforeModify();
+        final GLContextState o = cow.owner;
+        if (o != null && o.attribDepth > 0
+            && (stateUnknown || !GLStateManager.isCachingEnabled() || enabled != vanillaValue())) {
+            beforeModify();
+        }
         super.setEnabled(enabled);
     }
 

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/Color4Stack.java

@@ -1,50 +1,55 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.Color4;
 
-public class Color4Stack extends Color4 implements IStateStack<Color4Stack> {
+public final class Color4Stack extends Color4 implements CowStateStack<Color4Stack> {
 
     protected final Color4[] stack;
+    private CowDepths cow = new CowDepths();
 
-    protected int pointer;
-
-    public Color4Stack() {
+    public Color4Stack(int id) {
+        cow.id = id;
         stack = new Color4[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new Color4();
         }
     }
 
-    public Color4Stack(Color4 color4) {
-        this();
+    public Color4Stack(int id, Color4 color4) {
+        this(id);
         set(color4);
     }
 
-    public Color4Stack push() {
-        if(pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        stack[pointer++].set(this);
+    public Color4Stack restoreBit(int bit) {
+        final int id = cow.id;
+        cow = new CowDepths(bit);
+        cow.id = id;
         return this;
     }
 
-    public Color4Stack pop() {
-        if(pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
+    }
+
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,52 +1,51 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.StateSet;
 import com.gtnewhorizons.angelica.glsm.hooks.VanillaStateLayer;
 import com.gtnewhorizons.angelica.glsm.states.ColorMask;
 import lombok.Setter;
 
-public class ColorMaskStack extends ColorMask implements IStateStack<ColorMaskStack> {
+public final class ColorMaskStack extends ColorMask implements CowStateStack<ColorMaskStack> {
 
     protected final ColorMask[] stack;
-
-    protected int pointer;
+    private final CowDepths cow = new CowDepths(StateSet.R_COLOR_MASK);
 
     @Setter private VanillaStateLayer<ColorMask> vanillaLayer;
 
-    public ColorMaskStack() {
+    public ColorMaskStack(int id) {
+        cow.id = id;
         stack = new ColorMask[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new ColorMask();
         }
     }
 
-    public ColorMaskStack push() {
-        if(pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        VanillaStateLayer.capture(vanillaLayer, stack[pointer++].set(this));
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public ColorMaskStack pop() {
-        if(pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
+    @Override
+    public void captureSlot(int s) {
+        VanillaStateLayer.capture(vanillaLayer, stack[s].set(this));
+    }
 
-        final ColorMask saved = stack[--pointer];
+    @Override
+    public void restoreSlot(int s) {
+        final ColorMask saved = stack[s];
         if (!VanillaStateLayer.restore(vanillaLayer, saved)) {
             set(saved);
         }
-        return this;
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
     }
 
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -0,0 +1,71 @@
+package com.gtnewhorizons.angelica.glsm.stacks;
+
+import com.gtnewhorizons.angelica.glsm.GLContextState;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+
+/**
+ *            __n__n__
+ *     .------`-\00/-'
+ *    /  ##  ## (oo)
+ *   / \## __   ./
+ *      |//YY \|/
+ *      |||   |||
+ *    Copy On Write Depths
+ */
+
+public final class CowDepths {
+    public int id = -1;
+    public GLContextState owner;
+    public final int restoreBit;
+    public final int restoreUnit;
+    private final int[] slotDepth = new int[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
+    private int pointer;
+
+    public CowDepths() {
+        this(0, -1);
+    }
+
+    public CowDepths(int restoreBit) {
+        this(restoreBit, -1);
+    }
+
+    public CowDepths(int restoreBit, int restoreUnit) {
+        this.restoreBit = restoreBit;
+        this.restoreUnit = restoreUnit;
+    }
+
+    public int claim(int depth) {
+        if (depth <= 0) return -1;
+        if (pointer > 0 && slotDepth[pointer - 1] == depth) return -1;
+        slotDepth[pointer] = depth;
+        return pointer++;
+    }
+
+    public int claimUnconditional() {
+        slotDepth[pointer] = -1;
+        return pointer++;
+    }
+
+    public int pop() {
+        return pointer > 0 ? --pointer : -1;
+    }
+
+    public int discard(int poppedDepth) {
+        if (pointer == 0) return -1;
+        final int parent = poppedDepth - 1;
+        if (parent > 0 && (pointer < 2 || slotDepth[pointer - 2] != parent)) {
+            slotDepth[pointer - 1] = parent;
+            return pointer - 1;
+        }
+        pointer--;
+        return -1;
+    }
+
+    public int top() {
+        return pointer - 1;
+    }
+
+    public boolean isEmpty() {
+        return pointer == 0;
+    }
+}

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

@@ -0,0 +1,133 @@
+package com.gtnewhorizons.angelica.glsm.stacks;
+
+import com.gtnewhorizons.angelica.glsm.ClipPlaneBooleanState;
+import com.gtnewhorizons.angelica.glsm.states.TexEnvState;
+
+/**
+ *            __n__n__
+ *     .------`-\00/-'
+ *    /  ##  ## (oo)    Casts look redundant, they aren't. Casting to the
+ *   / \## __   ./      final class avoids an interface lookup on every
+ *      |//YY \|/       call. 74-85% faster push/pops in JMH testing.
+ *      |||   |||
+ *    Copy On Write Dispatch
+ */
+@SuppressWarnings("RedundantCast")
+public final class CowDispatch {
+
+    private CowDispatch() {}
+
+    public static final byte BLEND = 0;
+    public static final byte BOOLEAN = 1;
+    public static final byte CLIP_PLANE_BOOLEAN = 2;
+    public static final byte TEXTURE_UNIT_BOOLEAN = 3;
+    public static final byte COLOR_MASK = 4;
+    public static final byte LIGHT_STATE = 5;
+    public static final byte MATERIAL = 6;
+    public static final byte STENCIL = 7;
+    public static final byte MATRIX_MODE = 8;
+    public static final byte LIGHT_MODEL = 9;
+    public static final byte ALPHA = 10;
+    public static final byte POINT = 11;
+    public static final byte FOG = 12;
+    public static final byte VEC4F = 13;
+    public static final byte VEC3F = 14;
+    public static final byte INTEGER = 15;
+    public static final byte DEPTH = 16;
+    public static final byte VIEWPORT = 17;
+    public static final byte POLYGON = 18;
+    public static final byte COLOR4 = 19;
+    public static final byte LINE = 20;
+    public static final byte TEXTURE_BINDING = 21;
+    public static final byte TEX_ENV = 22;
+    public static final byte SCISSOR = 23;
+
+    public static byte kindOf(CowStateStack<?> s) {
+        final Class<?> c = s.getClass();
+        if (c == TextureUnitBooleanStateStack.class) return TEXTURE_UNIT_BOOLEAN;
+        if (c == ClipPlaneBooleanState.class) return CLIP_PLANE_BOOLEAN;
+        if (c == BooleanStateStack.class) return BOOLEAN;
+        if (c == BlendStateStack.class) return BLEND;
+        if (c == ColorMaskStack.class) return COLOR_MASK;
+        if (c == LightStateStack.class) return LIGHT_STATE;
+        if (c == MaterialStateStack.class) return MATERIAL;
+        if (c == StencilStateStack.class) return STENCIL;
+        if (c == MatrixModeStack.class) return MATRIX_MODE;
+        if (c == LightModelStateStack.class) return LIGHT_MODEL;
+        if (c == AlphaStateStack.class) return ALPHA;
+        if (c == PointStateStack.class) return POINT;
+        if (c == FogStateStack.class) return FOG;
+        if (c == Vec4fStack.class) return VEC4F;
+        if (c == Vec3fStack.class) return VEC3F;
+        if (c == IntegerStateStack.class) return INTEGER;
+        if (c == DepthStateStack.class) return DEPTH;
+        if (c == ViewPortStateStack.class) return VIEWPORT;
+        if (c == PolygonStateStack.class) return POLYGON;
+        if (c == Color4Stack.class) return COLOR4;
+        if (c == LineStateStack.class) return LINE;
+        if (c == TextureBindingStack.class) return TEXTURE_BINDING;
+        if (c == TexEnvState.class) return TEX_ENV;
+        if (c == ScissorStateStack.class) return SCISSOR;
+        throw new IllegalStateException("Unknown CowStateStack class: " + c.getName());
+    }
+
+    public static boolean topSlotChanged(byte kind, CowStateStack<?> s) {
+        return switch (kind) {
+            case BLEND -> ((BlendStateStack) s).topSlotChanged();
+            case BOOLEAN -> ((BooleanStateStack) s).topSlotChanged();
+            case CLIP_PLANE_BOOLEAN -> ((ClipPlaneBooleanState) s).topSlotChanged();
+            case TEXTURE_UNIT_BOOLEAN -> ((TextureUnitBooleanStateStack) s).topSlotChanged();
+            case COLOR_MASK -> ((ColorMaskStack) s).topSlotChanged();
+            case LIGHT_STATE -> ((LightStateStack) s).topSlotChanged();
+            case MATERIAL -> ((MaterialStateStack) s).topSlotChanged();
+            case STENCIL -> ((StencilStateStack) s).topSlotChanged();
+            case MATRIX_MODE -> ((MatrixModeStack) s).topSlotChanged();
+            case LIGHT_MODEL -> ((LightModelStateStack) s).topSlotChanged();
+            case ALPHA -> ((AlphaStateStack) s).topSlotChanged();
+            case POINT -> ((PointStateStack) s).topSlotChanged();
+            case FOG -> ((FogStateStack) s).topSlotChanged();
+            case VEC4F -> ((Vec4fStack) s).topSlotChanged();
+            case VEC3F -> ((Vec3fStack) s).topSlotChanged();
+            case INTEGER -> ((IntegerStateStack) s).topSlotChanged();
+            case DEPTH -> ((DepthStateStack) s).topSlotChanged();
+            case VIEWPORT -> ((ViewPortStateStack) s).topSlotChanged();
+            case POLYGON -> ((PolygonStateStack) s).topSlotChanged();
+            case COLOR4 -> ((Color4Stack) s).topSlotChanged();
+            case LINE -> ((LineStateStack) s).topSlotChanged();
+            case TEXTURE_BINDING -> ((TextureBindingStack) s).topSlotChanged();
+            case TEX_ENV -> ((TexEnvState) s).topSlotChanged();
+            case SCISSOR -> ((ScissorStateStack) s).topSlotChanged();
+            default -> throw new IllegalStateException("Unknown kind: " + kind);
+        };
+    }
+
+    public static void restoreSlot(byte kind, CowStateStack<?> s, int slot) {
+        switch (kind) {
+            case BLEND -> ((BlendStateStack) s).restoreSlot(slot);
+            case BOOLEAN -> ((BooleanStateStack) s).restoreSlot(slot);
+            case CLIP_PLANE_BOOLEAN -> ((ClipPlaneBooleanState) s).restoreSlot(slot);
+            case TEXTURE_UNIT_BOOLEAN -> ((TextureUnitBooleanStateStack) s).restoreSlot(slot);
+            case COLOR_MASK -> ((ColorMaskStack) s).restoreSlot(slot);
+            case LIGHT_STATE -> ((LightStateStack) s).restoreSlot(slot);
+            case MATERIAL -> ((MaterialStateStack) s).restoreSlot(slot);
+            case STENCIL -> ((StencilStateStack) s).restoreSlot(slot);
+            case MATRIX_MODE -> ((MatrixModeStack) s).restoreSlot(slot);
+            case LIGHT_MODEL -> ((LightModelStateStack) s).restoreSlot(slot);
+            case ALPHA -> ((AlphaStateStack) s).restoreSlot(slot);
+            case POINT -> ((PointStateStack) s).restoreSlot(slot);
+            case FOG -> ((FogStateStack) s).restoreSlot(slot);
+            case VEC4F -> ((Vec4fStack) s).restoreSlot(slot);
+            case VEC3F -> ((Vec3fStack) s).restoreSlot(slot);
+            case INTEGER -> ((IntegerStateStack) s).restoreSlot(slot);
+            case DEPTH -> ((DepthStateStack) s).restoreSlot(slot);
+            case VIEWPORT -> ((ViewPortStateStack) s).restoreSlot(slot);
+            case POLYGON -> ((PolygonStateStack) s).restoreSlot(slot);
+            case COLOR4 -> ((Color4Stack) s).restoreSlot(slot);
+            case LINE -> ((LineStateStack) s).restoreSlot(slot);
+            case TEXTURE_BINDING -> ((TextureBindingStack) s).restoreSlot(slot);
+            case TEX_ENV -> ((TexEnvState) s).restoreSlot(slot);
+            case SCISSOR -> ((ScissorStateStack) s).restoreSlot(slot);
+            default -> throw new IllegalStateException("Unknown kind: " + kind);
+        }
+    }
+}

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

@@ -0,0 +1,88 @@
+package com.gtnewhorizons.angelica.glsm.stacks;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
+import com.gtnewhorizons.angelica.glsm.GLContextState;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+
+/**
+ *            __n__n__
+ *     .------`-\00/-'
+ *    /  ##  ## (oo)
+ *   / \## __   ./
+ *      |//YY \|/
+ *      |||   |||
+ *    Copy On Write State Stack
+ */
+public interface CowStateStack<T> extends IStateStack<T> {
+    CowDepths cowDepths();
+
+    void captureSlot(int slot);
+
+    void restoreSlot(int slot);
+
+    default int stackId() {
+        return cowDepths().id;
+    }
+
+    default void setStackId(int id) {
+        cowDepths().id = id;
+    }
+
+    default int restoreBit() {
+        return cowDepths().restoreBit;
+    }
+
+    default int restoreUnit() {
+        return cowDepths().restoreUnit;
+    }
+
+    default boolean topSlotChanged() {
+        return false;
+    }
+
+    @Override
+    default int pushDepth() {
+        final GLContextState o = cowDepths().owner;
+        return o == null ? 0 : o.attribDepth;
+    }
+
+    @Override
+    default void beforeModify() {
+        final CowDepths d = cowDepths();
+        final GLContextState o = d.owner;
+        if (o == null) return;
+        final int s = d.claim(o.attribDepth);
+        if (s >= 0) {
+            captureSlot(s);
+            GLStateManager.registerModifiedState(o, d.id);
+        }
+    }
+
+    @Override
+    default boolean isEmpty() {
+        return cowDepths().isEmpty();
+    }
+
+    default void drain() {
+        int s;
+        while ((s = cowDepths().pop()) >= 0) restoreSlot(s);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    default T push() {
+        captureSlot(cowDepths().claimUnconditional());
+        return (T) this;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    default T pop() {
+        final int s = cowDepths().pop();
+        if (s < 0) {
+            throw new IllegalStateException("Stack underflow");
+        }
+        restoreSlot(s);
+        return (T) this;
+    }
+}

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

@@ -1,49 +1,51 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.StateSet;
 import com.gtnewhorizons.angelica.glsm.hooks.VanillaStateLayer;
 import com.gtnewhorizons.angelica.glsm.states.DepthState;
 import lombok.Setter;
 
-public class DepthStateStack extends DepthState implements IStateStack<DepthStateStack> {
+public final class DepthStateStack extends DepthState implements CowStateStack<DepthStateStack> {
 
     protected final DepthState[] stack;
-
-    protected int pointer;
+    private final CowDepths cow = new CowDepths(StateSet.R_DEPTH);
 
     @Setter private VanillaStateLayer<DepthState> vanillaLayer;
 
     private final DepthState effective = new DepthState();
 
-    public DepthStateStack() {
+    public DepthStateStack(int id) {
+        cow.id = id;
         stack = new DepthState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new DepthState();
         }
     }
 
-    public DepthStateStack push() {
-        if(pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        VanillaStateLayer.capture(vanillaLayer, stack[pointer++].set(this));
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public DepthStateStack pop() {
-        if(pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
+    @Override
+    public void captureSlot(int s) {
+        VanillaStateLayer.capture(vanillaLayer, stack[s].set(this));
+    }
 
-        final DepthState saved = stack[--pointer];
+    @Override
+    public void restoreSlot(int s) {
+        final DepthState saved = stack[s];
         if (VanillaStateLayer.restore(vanillaLayer, saved)) {
             setExceptMask(saved);
         } else {
             set(saved);
         }
-        return this;
+    }
+
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
     }
 
     public boolean isEffectiveMaskEnabled() {
@@ -52,11 +54,8 @@ public class DepthStateStack extends DepthState implements IStateStack<DepthStat
         return effective.isEnabled();
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
-    }
-
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,41 +1,38 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.FogState;
 
-public class FogStateStack extends FogState implements IStateStack<FogStateStack> {
+public final class FogStateStack extends FogState implements CowStateStack<FogStateStack> {
 
     protected final FogState[] stack;
+    private final CowDepths cow = new CowDepths();
 
-    protected int pointer;
-
-    public FogStateStack() {
+    public FogStateStack(int id) {
+        cow.id = id;
         stack = new FogState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new FogState();
         }
     }
 
-    public FogStateStack push() {
-        if(pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public FogStateStack pop() {
-        if(pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,16 +1,15 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.IntegerState;
 
-public class IntegerStateStack extends IntegerState implements IStateStack<IntegerStateStack> {
+public final class IntegerStateStack extends IntegerState implements CowStateStack<IntegerStateStack> {
 
     protected final IntegerState[] stack;
+    private CowDepths cow = new CowDepths();
 
-    protected int pointer;
-
-    public IntegerStateStack(int val) {
+    public IntegerStateStack(int val, int id) {
+        cow.id = id;
         setValue(val);
         stack = new IntegerState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
@@ -19,34 +18,40 @@ public class IntegerStateStack extends IntegerState implements IStateStack<Integ
         }
     }
 
-    public IntegerStateStack push() {
-        if(pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        stack[pointer++].set(this);
+    public IntegerStateStack restoreBit(int bit) {
+        final int id = cow.id;
+        cow = new CowDepths(bit);
+        cow.id = id;
         return this;
     }
 
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
+    }
+
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
+    }
+
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
+    }
+
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
+    }
+
     public IntegerStateStack push(int value) {
         push().setValue(value);
         return this;
     }
 
-    public IntegerStateStack pop() {
-        if(pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-
-        set(stack[--pointer]);
-        return this;
-    }
-
-    public boolean isEmpty() {
-        return pointer == 0;
-    }
-
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,40 +1,39 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.LightModelState;
 
-public class LightModelStateStack extends LightModelState implements IStateStack<LightModelStateStack> {
+public final class LightModelStateStack extends LightModelState implements CowStateStack<LightModelStateStack> {
 
     protected final LightModelState[] stack;
+    private final CowDepths cow = new CowDepths();
 
-    protected int pointer;
-
-    public LightModelStateStack() {
+    public LightModelStateStack(int id) {
         super();
+        cow.id = id;
         stack = new LightModelState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new LightModelState();
         }
     }
 
-    public LightModelStateStack push() {
-        if (pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public LightModelStateStack pop() {
-        if (pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean isEmpty() { return pointer == 0; }
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
+    }
 }

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

@@ -1,40 +1,39 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.LightState;
 
-public class LightStateStack extends LightState implements IStateStack<LightStateStack> {
+public final class LightStateStack extends LightState implements CowStateStack<LightStateStack> {
 
     protected final LightState[] stack;
+    private final CowDepths cow = new CowDepths();
 
-    protected int pointer;
-
-    public LightStateStack(int light) {
+    public LightStateStack(int light, int id) {
         super(light);
+        cow.id = id;
         stack = new LightState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new LightState(light);
         }
     }
 
-    public LightStateStack push() {
-        if (pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public LightStateStack pop() {
-        if (pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean isEmpty() { return pointer == 0; }
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
+    }
 }

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

@@ -1,46 +1,44 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.StateSet;
 import com.gtnewhorizons.angelica.glsm.states.LineState;
 
-/**
- * Stack for GL line state (width, stipple factor, stipple pattern).
- * Used by GL_LINE_BIT push/pop attrib.
- */
-public class LineStateStack extends LineState implements IStateStack<LineStateStack> {
+public final class LineStateStack extends LineState implements CowStateStack<LineStateStack> {
 
     protected final LineState[] stack;
-    protected int pointer;
+    private final CowDepths cow = new CowDepths(StateSet.R_LINE);
 
-    public LineStateStack() {
+    public LineStateStack(int id) {
+        cow.id = id;
         stack = new LineState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new LineState();
         }
     }
 
-    public LineStateStack push() {
-        if (pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public LineStateStack pop() {
-        if (pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
     }
 
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,42 +1,39 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.MaterialState;
 
-public class MaterialStateStack extends MaterialState implements IStateStack<MaterialStateStack> {
+public final class MaterialStateStack extends MaterialState implements CowStateStack<MaterialStateStack> {
 
     protected final MaterialState[] stack;
+    private final CowDepths cow = new CowDepths();
 
-    protected int pointer;
-
-    public MaterialStateStack(int face) {
+    public MaterialStateStack(int face, int id) {
         super(face);
+        cow.id = id;
         stack = new MaterialState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new MaterialState(face);
         }
     }
 
-    public MaterialStateStack push() {
-        if (pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public MaterialStateStack pop() {
-        if (pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean isEmpty() { return pointer == 0; }
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
+    }
 
+    @Override
+    public int stackId() {
+        return cow.id;
+    }
 }
-

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

@@ -1,41 +1,38 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.states.MatrixMode;
 
-public class MatrixModeStack extends MatrixMode implements IStateStack<MatrixModeStack> {
+public final class MatrixModeStack extends MatrixMode implements CowStateStack<MatrixModeStack> {
 
     protected final MatrixMode[] stack;
+    private final CowDepths cow = new CowDepths();
 
-    protected int pointer;
-
-    public MatrixModeStack() {
+    public MatrixModeStack(int id) {
+        cow.id = id;
         stack = new MatrixMode[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new MatrixMode();
         }
     }
 
-    public MatrixModeStack push() {
-        if(pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public MatrixModeStack pop() {
-        if(pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,46 +1,44 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.StateSet;
 import com.gtnewhorizons.angelica.glsm.states.PointState;
 
-/**
- * Stack for GL point state (size).
- * Used by GL_POINT_BIT push/pop attrib.
- */
-public class PointStateStack extends PointState implements IStateStack<PointStateStack> {
+public final class PointStateStack extends PointState implements CowStateStack<PointStateStack> {
 
     protected final PointState[] stack;
-    protected int pointer;
+    private final CowDepths cow = new CowDepths(StateSet.R_POINT);
 
-    public PointStateStack() {
+    public PointStateStack(int id) {
+        cow.id = id;
         stack = new PointState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new PointState();
         }
     }
 
-    public PointStateStack push() {
-        if (pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public PointStateStack pop() {
-        if (pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
     }
 
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,46 +1,44 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.StateSet;
 import com.gtnewhorizons.angelica.glsm.states.PolygonState;
 
-/**
- * Stack for GL polygon state (mode, offset, cull face mode, front face).
- * Used by GL_POLYGON_BIT push/pop attrib.
- */
-public class PolygonStateStack extends PolygonState implements IStateStack<PolygonStateStack> {
+public final class PolygonStateStack extends PolygonState implements CowStateStack<PolygonStateStack> {
 
     protected final PolygonState[] stack;
-    protected int pointer;
+    private final CowDepths cow = new CowDepths(StateSet.R_POLYGON);
 
-    public PolygonStateStack() {
+    public PolygonStateStack(int id) {
+        cow.id = id;
         stack = new PolygonState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new PolygonState();
         }
     }
 
-    public PolygonStateStack push() {
-        if (pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public PolygonStateStack pop() {
-        if (pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
     }
 
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -0,0 +1,44 @@
+package com.gtnewhorizons.angelica.glsm.stacks;
+
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.StateSet;
+import com.gtnewhorizons.angelica.glsm.states.ScissorState;
+
+public final class ScissorStateStack extends ScissorState implements CowStateStack<ScissorStateStack> {
+
+    protected final ScissorState[] stack;
+    private final CowDepths cow = new CowDepths(StateSet.R_SCISSOR);
+
+    public ScissorStateStack(int id) {
+        cow.id = id;
+        stack = new ScissorState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
+        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+            stack[i] = new ScissorState();
+        }
+    }
+
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
+    }
+
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
+    }
+
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
+    }
+
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
+    }
+}

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

@@ -0,0 +1,30 @@
+package com.gtnewhorizons.angelica.glsm.stacks;
+
+public final class StackIdAllocator {
+
+    private StackIdAllocator() {}
+
+    private static int next = -1;
+    private static int perContext = -1;
+
+    public static void beginContext() {
+        next = 0;
+    }
+
+    public static void endContext() {
+        if (perContext == -1) {
+            perContext = next;
+        } else if (next != perContext) {
+            throw new IllegalStateException("stack id count changed across contexts: " + perContext + " -> " + next);
+        }
+        next = -1;
+    }
+
+    public static int nextId() {
+        return next >= 0 ? next++ : -1;
+    }
+
+    public static int allocated() {
+        return next;
+    }
+}

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

@@ -1,46 +1,44 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.StateSet;
 import com.gtnewhorizons.angelica.glsm.states.StencilState;
 
-/**
- * Stack for GL stencil buffer state.
- * Used by GL_STENCIL_BUFFER_BIT push/pop attrib.
- */
-public class StencilStateStack extends StencilState implements IStateStack<StencilStateStack> {
+public final class StencilStateStack extends StencilState implements CowStateStack<StencilStateStack> {
 
     protected final StencilState[] stack;
-    protected int pointer;
+    private final CowDepths cow = new CowDepths(StateSet.R_STENCIL);
 
-    public StencilStateStack() {
+    public StencilStateStack(int id) {
+        cow.id = id;
         stack = new StencilState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new StencilState();
         }
     }
 
-    public StencilStateStack push() {
-        if (pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public StencilStateStack pop() {
-        if (pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
     }
 
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,49 +1,45 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.StateSet;
 import com.gtnewhorizons.angelica.glsm.states.TextureBinding;
 
-public class TextureBindingStack extends TextureBinding implements IStateStack<TextureBindingStack> {
+public final class TextureBindingStack extends TextureBinding implements CowStateStack<TextureBindingStack> {
 
     protected final TextureBinding[] stack;
+    private final CowDepths cow;
 
-    protected int pointer;
-
-    public TextureBindingStack() {
+    public TextureBindingStack(int id, int unit) {
+        cow = new CowDepths(StateSet.R_TEXTURE, unit);
+        cow.id = id;
         stack = new TextureBinding[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new TextureBinding();
         }
     }
 
-    public TextureBindingStack push() {
-        if(pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public TextureBindingStack pop() {
-        if(pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public TextureBinding peek() {
-        return stack[pointer];
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
     }
 
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -9,7 +9,7 @@ import org.lwjgl.opengl.GL13;
  * BooleanStateStack for per-texture-unit state.
  * Switches to correct unit (raw GL) before enable/disable calls.
  */
-public class TextureUnitBooleanStateStack extends BooleanStateStack {
+public final class TextureUnitBooleanStateStack extends BooleanStateStack {
     private final int unitIndex;
 
     public TextureUnitBooleanStateStack(int glCap, int unitIndex) {
@@ -29,12 +29,8 @@ public class TextureUnitBooleanStateStack extends BooleanStateStack {
     }
 
     @Override
-    public TextureUnitBooleanStateStack popDepth() {
-        if (savedDepth > 0) {
-            final boolean oldValue = stack[--savedDepth];
-            setEnabledWithUnitSwitch(oldValue);
-        }
-        return this;
+    public void restoreSlot(int slot) {
+        setEnabledWithUnitSwitch(stack[slot]);
     }
 
     private void setEnabledWithUnitSwitch(boolean enabled) {

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

@@ -1,47 +1,42 @@
 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> {
+public final class Vec3fStack implements CowStateStack<Vec3fStack> {
 
     private final Vector3f value;
     private final float[][] stack;
-    private int pointer;
+    private final CowDepths cow = new CowDepths();
 
-    public Vec3fStack(Vector3f value) {
+    public Vec3fStack(Vector3f value, int id) {
         this.value = value;
+        cow.id = id;
         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;
+    public CowDepths cowDepths() {
+        return cow;
     }
 
     @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;
+    public void captureSlot(int s) {
+        stack[s][0] = value.x;
+        stack[s][1] = value.y;
+        stack[s][2] = value.z;
     }
 
     @Override
-    public boolean isEmpty() {
-        return pointer == 0;
+    public void restoreSlot(int s) {
+        value.set(stack[s][0], stack[s][1], stack[s][2]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,48 +1,43 @@
 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> {
+public final class Vec4fStack implements CowStateStack<Vec4fStack> {
 
     private final Vector4f value;
     private final float[][] stack;
-    private int pointer;
+    private final CowDepths cow = new CowDepths();
 
-    public Vec4fStack(Vector4f value) {
+    public Vec4fStack(Vector4f value, int id) {
         this.value = value;
+        cow.id = id;
         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;
+    public CowDepths cowDepths() {
+        return cow;
     }
 
     @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;
+    public void captureSlot(int s) {
+        stack[s][0] = value.x;
+        stack[s][1] = value.y;
+        stack[s][2] = value.z;
+        stack[s][3] = value.w;
     }
 
     @Override
-    public boolean isEmpty() {
-        return pointer == 0;
+    public void restoreSlot(int s) {
+        value.set(stack[s][0], stack[s][1], stack[s][2], stack[s][3]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -1,45 +1,44 @@
 package com.gtnewhorizons.angelica.glsm.stacks;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.StateSet;
 import com.gtnewhorizons.angelica.glsm.states.ViewportState;
 
-public class ViewPortStateStack extends ViewportState implements IStateStack<ViewPortStateStack> {
+public final class ViewPortStateStack extends ViewportState implements CowStateStack<ViewPortStateStack> {
 
     protected final ViewportState[] stack;
+    private final CowDepths cow = new CowDepths(StateSet.R_VIEWPORT);
 
-    protected int pointer;
-
-    public ViewPortStateStack() {
+    public ViewPortStateStack(int id) {
+        cow.id = id;
         stack = new ViewportState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
         for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
             stack[i] = new ViewportState();
         }
     }
 
-    public ViewPortStateStack push() {
-        if(pointer == stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-
-        stack[pointer++].set(this);
-        return this;
+    @Override
+    public CowDepths cowDepths() {
+        return cow;
     }
 
-    public ViewPortStateStack pop() {
-        if(pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-
-        set(stack[--pointer]);
-        return this;
+    @Override
+    public void captureSlot(int s) {
+        stack[s].set(this);
     }
 
-    public boolean isEmpty() {
-        return pointer == 0;
+    @Override
+    public void restoreSlot(int s) {
+        set(stack[s]);
     }
 
-    public boolean topChanged() {
-        return pointer > 0 && !sameAs(stack[pointer - 1]);
+    @Override
+    public boolean topSlotChanged() {
+        return !cow.isEmpty() && !sameAs(stack[cow.top()]);
+    }
+
+    @Override
+    public int stackId() {
+        return cow.id;
     }
 }

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

@@ -48,6 +48,7 @@ public class BooleanState implements ISettableState<BooleanState> {
         if (stateUnknown || bypass || enabled != this.enabled || (this.glCap == GL11.GL_BLEND && GLStateManager.vendorIsAMD() && GLStateManager.isPoppingAttributes())) {
             stateUnknown = false;
             this.enabled = enabled;
+            onEnabledChanged();
             if (!ffpStateOnly) {
                 if (enabled) {
                     RENDER_BACKEND.enable(this.glCap);
@@ -58,6 +59,8 @@ public class BooleanState implements ISettableState<BooleanState> {
         }
     }
 
+    protected void onEnabledChanged() {}
+
     @Override
     public BooleanState set(BooleanState state) {
         this.enabled = state.enabled;

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

@@ -0,0 +1,54 @@
+package com.gtnewhorizons.angelica.glsm.states;
+
+import java.nio.IntBuffer;
+
+public class ScissorState implements ISettableState<ScissorState> {
+    public int x;
+    public int y;
+    public int width;
+    public int height;
+
+    public void setScissor(int x, int y, int width, int height) {
+        this.x = x;
+        this.y = y;
+        this.width = width;
+        this.height = height;
+    }
+
+    public void get(IntBuffer params) {
+        params.put(0, x);
+        params.put(1, y);
+        params.put(2, width);
+        params.put(3, height);
+    }
+
+    public void get(int[] params) {
+        params[0] = x;
+        params[1] = y;
+        params[2] = width;
+        params[3] = height;
+    }
+
+    @Override
+    public ScissorState set(ScissorState state) {
+        this.x = state.x;
+        this.y = state.y;
+        this.width = state.width;
+        this.height = state.height;
+
+        return this;
+    }
+
+    @Override
+    public boolean sameAs(Object state) {
+        if (this == state) return true;
+        if (!(state instanceof ScissorState scissorState)) return false;
+        return x == scissorState.x && y == scissorState.y && width == scissorState.width && height == scissorState.height;
+    }
+
+    @Override
+    public ScissorState copy() {
+        return new ScissorState().set(this);
+    }
+
+}

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

@@ -1,14 +1,15 @@
 package com.gtnewhorizons.angelica.glsm.states;
 
-import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.stacks.CowDepths;
+import com.gtnewhorizons.angelica.glsm.stacks.CowStateStack;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL13;
 
 /**
  * Per-texture-unit GL_TEXTURE_ENV state for FFP emulation. Tracks the simple texenv mode and all GL_COMBINE sub-parameters.
  */
-public class TexEnvState implements IStateStack<TexEnvState> {
+public final class TexEnvState implements CowStateStack<TexEnvState> {
 
     public int mode;
 
@@ -30,22 +31,25 @@ public class TexEnvState implements IStateStack<TexEnvState> {
     public float envColorA;
 
     private final TexEnvState[] stack;
-    private int pointer;
+    private final CowDepths cow;
     private final boolean isStackEntry;
 
-    public TexEnvState() {
+    public TexEnvState(int id) {
         this(false);
+        cow.id = id;
     }
 
     private TexEnvState(boolean isStackEntry) {
         this.isStackEntry = isStackEntry;
         if (isStackEntry) {
             stack = null;
+            cow = null;
         } else {
             stack = new TexEnvState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
             for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
                 stack[i] = new TexEnvState(true);
             }
+            cow = new CowDepths();
         }
         reset();
     }
@@ -80,31 +84,27 @@ public class TexEnvState implements IStateStack<TexEnvState> {
     }
 
     @Override
-    public TexEnvState push() {
-        if (stack == null) throw new IllegalStateException("Cannot push stack entry");
-        if (pointer >= stack.length) {
-            throw new IllegalStateException("Stack overflow size " + (pointer + 1) + " reached");
-        }
-        stack[pointer++].copyFrom(this);
-        return this;
+    public CowDepths cowDepths() {
+        if (cow == null) throw new IllegalStateException("Cannot push/pop a stack entry");
+        return cow;
     }
 
     @Override
-    public TexEnvState pop() {
-        if (stack == null) throw new IllegalStateException("Cannot pop stack entry");
-        if (pointer == 0) {
-            throw new IllegalStateException("Stack underflow");
-        }
-        copyFrom(stack[--pointer]);
-        return this;
+    public void captureSlot(int s) {
+        stack[s].copyFrom(this);
     }
 
     @Override
-    public boolean isEmpty() {
-        return pointer == 0;
+    public void restoreSlot(int s) {
+        copyFrom(stack[s]);
     }
 
     public boolean isCombineMode() {
         return mode == GL13.GL_COMBINE;
     }
+
+    @Override
+    public int stackId() {
+        return cow == null ? -1 : cow.id;
+    }
 }

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

@@ -1,6 +1,8 @@
 package com.gtnewhorizons.angelica.glsm.states;
 
+import com.gtnewhorizon.gtnhlib.client.renderer.stacks.IStateStack;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.stacks.StackIdAllocator;
 import com.gtnewhorizons.angelica.glsm.stacks.TextureBindingStack;
 import com.gtnewhorizons.angelica.glsm.stacks.TextureUnitBooleanStateStack;
 import lombok.Getter;
@@ -8,7 +10,11 @@ import org.joml.Matrix4fStack;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL12;
 
+import java.util.ArrayList;
+import java.util.List;
+
 public class TextureUnitArray {
+    private final List<IStateStack<?>> idStacks = new ArrayList<>();
     private final TextureBindingStack[] bindings;
     private final TextureUnitBooleanStateStack[] states;
     private final TextureUnitBooleanStateStack[] texture1DStates;
@@ -22,6 +28,9 @@ public class TextureUnitArray {
     @Getter
     public final Matrix4fStack[] textureMatricies;
 
+    public int texMatIdentityMask;
+    public int texMatIdentityGen;
+
     public TextureUnitArray() {
         bindings = new TextureBindingStack[GLStateManager.MAX_TEXTURE_UNITS];
         states = new TextureUnitBooleanStateStack[GLStateManager.MAX_TEXTURE_UNITS];
@@ -36,20 +45,35 @@ public class TextureUnitArray {
         textureMatricies = new Matrix4fStack[GLStateManager.MAX_TEXTURE_UNITS];
 
         for (int i = 0; i < GLStateManager.MAX_TEXTURE_UNITS; i++) {
-            bindings[i] = new TextureBindingStack();
-            states[i] = new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_2D, i);
-            texture1DStates[i] = new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_1D, i);
-            texture3DStates[i] = new TextureUnitBooleanStateStack(GL12.GL_TEXTURE_3D, i);
-            texGenSStates[i] = new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_GEN_S, i);
-            texGenTStates[i] = new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_GEN_T, i);
-            texGenRStates[i] = new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_GEN_R, i);
-            texGenQStates[i] = new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_GEN_Q, i);
+            bindings[i] = member(new TextureBindingStack(StackIdAllocator.nextId(), i));
+            states[i] = track(new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_2D, i));
+            texture1DStates[i] = track(new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_1D, i));
+            texture3DStates[i] = track(new TextureUnitBooleanStateStack(GL12.GL_TEXTURE_3D, i));
+            texGenSStates[i] = track(new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_GEN_S, i));
+            texGenTStates[i] = track(new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_GEN_T, i));
+            texGenRStates[i] = track(new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_GEN_R, i));
+            texGenQStates[i] = track(new TextureUnitBooleanStateStack(GL11.GL_TEXTURE_GEN_Q, i));
             texGenStates[i] = new TexGenState();
-            texEnvStates[i] = new TexEnvState();
+            texEnvStates[i] = member(new TexEnvState(StackIdAllocator.nextId()));
             textureMatricies[i] = new Matrix4fStack(GLStateManager.MAX_TEXTURE_STACK_DEPTH);
         }
     }
 
+    private <T extends TextureUnitBooleanStateStack> T track(T s) {
+        s.setStackId(StackIdAllocator.nextId());
+        idStacks.add(s);
+        return s;
+    }
+
+    private <T extends IStateStack<?>> T member(T s) {
+        idStacks.add(s);
+        return s;
+    }
+
+    public List<IStateStack<?>> idStacks() {
+        return idStacks;
+    }
+
     public TextureBindingStack getTextureUnitBindings(int index) {
         return bindings[index];
     }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/streaming/StreamingVaos.java

@@ -0,0 +1,13 @@
+package com.gtnewhorizons.angelica.glsm.streaming;
+
+import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
+
+public final class StreamingVaos {
+    private static final int FORMAT_COUNT = VertexFlags.BITSET_SIZE;
+
+    final int[] persistentVAOs = new int[FORMAT_COUNT];
+    final int[] orphanVAOs = new int[FORMAT_COUNT];
+
+    final int[] extendedPersistentVAOs = new int[FORMAT_COUNT];
+    final int[] extendedOrphanVAOs = new int[FORMAT_COUNT];
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/streaming/TessellatorStreamingDrawer.java

@@ -6,6 +6,7 @@ import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFlags;
 import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormat;
 import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement;
 import com.gtnewhorizons.angelica.config.SystemProperties;
+import com.gtnewhorizons.angelica.glsm.GLContextState;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.QuadConverter;
 import com.gtnewhorizons.angelica.glsm.RenderSystem;
@@ -47,11 +48,6 @@ public class TessellatorStreamingDrawer {
     private static PersistentStreamingBuffer persistentBuffer;
     private static final OrphanStreamingBuffer[] orphanBuffers = new OrphanStreamingBuffer[FORMAT_COUNT];
 
-    private static final int[] persistentVAOs = new int[FORMAT_COUNT];
-    private static final int[] orphanVAOs = new int[FORMAT_COUNT];
-
-    private static final int[] extendedPersistentVAOs = new int[FORMAT_COUNT];
-    private static final int[] extendedOrphanVAOs = new int[FORMAT_COUNT];
     private static ByteBuffer extScratch;
     private static long extScratchAddress;
     private static int extScratchCapacity;
@@ -243,13 +239,18 @@ public class TessellatorStreamingDrawer {
         final int normalOffset = ImmediateExtendedAttribHandler.normalOffset(format);
         final int combinedStride = vertexSize + ImmediateExtendedAttribHandler.EXT_STRIDE;
         final int combinedBytes = vertexCount * combinedStride;
-        ensureExtScratch(combinedBytes);
-        interleaveBase(srcBase, extScratchAddress, vertexCount, vertexSize, combinedStride);
-        extHandler.buildPacked(srcBase, vertexSize, 0, texOffset, normalOffset, vertexCount, extPrim, extScratchAddress + vertexSize, combinedStride);
-        extScratch.position(0);
-        extScratch.limit(combinedBytes);
-        uploadAndDrawExtended(extScratch, flags, format, combinedStride, drawMode, vertexCount);
-        shrinkExtScratchIfOversized(combinedBytes);
+        final boolean locked = GLStateManager.acquireDrawLock();
+        try {
+            ensureExtScratch(combinedBytes);
+            interleaveBase(srcBase, extScratchAddress, vertexCount, vertexSize, combinedStride);
+            extHandler.buildPacked(srcBase, vertexSize, 0, texOffset, normalOffset, vertexCount, extPrim, extScratchAddress + vertexSize, combinedStride);
+            extScratch.position(0);
+            extScratch.limit(combinedBytes);
+            uploadAndDrawExtended(extScratch, flags, format, combinedStride, drawMode, vertexCount);
+            shrinkExtScratchIfOversized(combinedBytes);
+        } finally {
+            if (locked) GLStateManager.releaseDrawLock();
+        }
         return true;
     }
 
@@ -311,7 +312,9 @@ public class TessellatorStreamingDrawer {
         Tracy.beginZone(Z_SDL_STREAM_DRAW);
         final boolean locked = GLStateManager.acquireDrawLock();
         try {
-            ensureVAO(flags, format);
+            final GLContextState glCtx = GLStateManager.ctx();
+            final StreamingVaos vaos = glCtx.streamingVaos;
+            ensureVAO(vaos, flags, format);
 
             if (Tracy.ENABLED) {
                 streamedBytes += packed.remaining();
@@ -326,10 +329,10 @@ public class TessellatorStreamingDrawer {
 
             final boolean fromRing = firstVertex >= 0;
             if (fromRing) {
-                GLStateManager.glBindVertexArray(persistentVAOs[flags]);
+                GLStateManager.glBindVertexArray(vaos.persistentVAOs[flags]);
             } else {
                 if (Tracy.ENABLED && persistentBuffer != null) orphanFallbacks++;
-                GLStateManager.glBindVertexArray(orphanVAOs[flags]);
+                GLStateManager.glBindVertexArray(vaos.orphanVAOs[flags]);
                 orphanBuffers[flags].upload(packed);
                 firstVertex = 0;
             }
@@ -340,7 +343,7 @@ public class TessellatorStreamingDrawer {
                 lastStreamDrawMode = drawMode;
             }
 
-            drawWithQuadConversion(drawMode, firstVertex, vertexCount);
+            drawWithQuadConversion(glCtx, drawMode, firstVertex, vertexCount);
             GLStateManager.glBindVertexArray(0);
         } finally {
             if (locked) GLStateManager.releaseDrawLock();
@@ -352,11 +355,11 @@ public class TessellatorStreamingDrawer {
         return persistentBuffer == null ? 0L : persistentBuffer.getWraps();
     }
 
-    private static void drawWithQuadConversion(int drawMode, int firstVertex, int vertexCount) {
+    private static void drawWithQuadConversion(GLContextState glCtx, int drawMode, int firstVertex, int vertexCount) {
         FfpExtendedAttribs.beginInternalDraw();
         try {
             if (drawMode == GL11.GL_QUADS) {
-                QuadConverter.drawQuadsAsTriangles(firstVertex, vertexCount);
+                QuadConverter.drawQuadsAsTriangles(glCtx, firstVertex, vertexCount);
             } else {
                 GLStateManager.glDrawArrays(drawMode, firstVertex, vertexCount);
             }
@@ -366,8 +369,10 @@ public class TessellatorStreamingDrawer {
     }
 
     private static void uploadAndDrawExtended(ByteBuffer combined, int flags, VertexFormat format, int combinedStride, int drawMode, int vertexCount) {
-        ensureVAO(flags, format);
-        ensureExtendedVAOs(flags, format);
+        final GLContextState glCtx = GLStateManager.ctx();
+        final StreamingVaos vaos = glCtx.streamingVaos;
+        ensureVAO(vaos, flags, format);
+        ensureExtendedVAOs(vaos, flags, format);
 
         int firstVertex = -1;
 
@@ -376,18 +381,20 @@ public class TessellatorStreamingDrawer {
         }
 
         if (firstVertex >= 0) {
-            GLStateManager.glBindVertexArray(extendedPersistentVAOs[flags]);
+            GLStateManager.glBindVertexArray(vaos.extendedPersistentVAOs[flags]);
         } else {
-            GLStateManager.glBindVertexArray(extendedOrphanVAOs[flags]);
+            GLStateManager.glBindVertexArray(vaos.extendedOrphanVAOs[flags]);
             orphanBuffers[flags].upload(combined);
             firstVertex = 0;
         }
 
-        drawWithQuadConversion(drawMode, firstVertex, vertexCount);
+        drawWithQuadConversion(glCtx, drawMode, firstVertex, vertexCount);
         GLStateManager.glBindVertexArray(0);
     }
 
-    private static void ensureExtendedVAOs(int flags, VertexFormat format) {
+    private static void ensureExtendedVAOs(StreamingVaos vaos, int flags, VertexFormat format) {
+        final int[] extendedOrphanVAOs = vaos.extendedOrphanVAOs;
+        final int[] extendedPersistentVAOs = vaos.extendedPersistentVAOs;
         if (extendedOrphanVAOs[flags] == 0) {
             extendedOrphanVAOs[flags] = GLStateManager.glGenVertexArrays();
             GLStateManager.glBindVertexArray(extendedOrphanVAOs[flags]);
@@ -467,12 +474,13 @@ public class TessellatorStreamingDrawer {
         return repackBuffer;
     }
 
-    private static void ensureVAO(int flags, VertexFormat format) {
+    private static void ensureVAO(StreamingVaos vaos, int flags, VertexFormat format) {
         init();
+        if (orphanBuffers[flags] == null) orphanBuffers[flags] = new OrphanStreamingBuffer();
+        final int[] orphanVAOs = vaos.orphanVAOs;
+        final int[] persistentVAOs = vaos.persistentVAOs;
 
         if (orphanVAOs[flags] == 0) {
-            orphanBuffers[flags] = new OrphanStreamingBuffer();
-
             orphanVAOs[flags] = GLStateManager.glGenVertexArrays();
             GLStateManager.glBindVertexArray(orphanVAOs[flags]);
             GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, orphanBuffers[flags].getBufferId());
@@ -489,33 +497,4 @@ public class TessellatorStreamingDrawer {
         }
     }
 
-    /**
-     * Clean up all VAOs, streaming buffers, and the repack buffer.
-     */
-    public static void destroy() {
-        for (int i = 0; i < FORMAT_COUNT; i++) {
-            if (persistentVAOs[i] != 0) { GLStateManager.glDeleteVertexArrays(persistentVAOs[i]); persistentVAOs[i] = 0; }
-            if (orphanVAOs[i] != 0) { GLStateManager.glDeleteVertexArrays(orphanVAOs[i]); orphanVAOs[i] = 0; }
-            if (extendedPersistentVAOs[i] != 0) { GLStateManager.glDeleteVertexArrays(extendedPersistentVAOs[i]); extendedPersistentVAOs[i] = 0; }
-            if (extendedOrphanVAOs[i] != 0) { GLStateManager.glDeleteVertexArrays(extendedOrphanVAOs[i]); extendedOrphanVAOs[i] = 0; }
-            if (orphanBuffers[i] != null) { orphanBuffers[i].destroy(); orphanBuffers[i] = null; }
-        }
-        if (extScratch != null) {
-            memFree(extScratch);
-            extScratch = null;
-            extScratchAddress = 0;
-            extScratchCapacity = 0;
-        }
-        if (persistentBuffer != null) {
-            persistentBuffer.destroy();
-            persistentBuffer = null;
-        }
-        if (repackBuffer != null) {
-            memFree(repackBuffer);
-            repackBuffer = null;
-            repackAddress = 0;
-            repackCapacity = 0;
-        }
-        initialized = false;
-    }
 }

glsm/src/main/resources/assets/angelica/shaders/combined_glint.frag.glsl

@@ -0,0 +1,56 @@
+out vec4 fragColor;
+
+vec4 glintLayer(vec4 coord, out bool visible) {
+    vec4 color = textureProj(u_Sampler0, coord) * v_Color;
+#if GLINT_OVERLAY == 2
+    color.rgb = mix(color.rgb, v_Overlay.rgb, v_Overlay.a);
+#elif GLINT_OVERLAY == 1
+    color.rgb = mix(color.rgb, u_OverlayColor.rgb, u_OverlayColor.a);
+#endif
+#if GLINT_LIGHTMAP
+    color *= textureProj(u_Sampler1, v_TexCoord1);
+#endif
+    float qa = round(color.a * 255.0);
+    float ref = u_AlphaRef * 255.0;
+#if GLINT_ALPHA_FUNC == 0
+    visible = false;
+#elif GLINT_ALPHA_FUNC == 1
+    visible = qa < ref;
+#elif GLINT_ALPHA_FUNC == 2
+    visible = qa == round(ref);
+#elif GLINT_ALPHA_FUNC == 3
+    visible = qa <= ref;
+#elif GLINT_ALPHA_FUNC == 4
+    visible = qa > ref;
+#elif GLINT_ALPHA_FUNC == 5
+    visible = qa != round(ref);
+#elif GLINT_ALPHA_FUNC == 6
+    visible = qa >= ref;
+#else
+    visible = true;
+#endif
+    if (!visible) return vec4(0.0);
+#if GLINT_FOG_MODE == 1
+    float fog = v_FogCoord * u_FogParams.x + u_FogParams.y;
+#elif GLINT_FOG_MODE == 2
+    float fog = exp2(-(v_FogCoord * u_FogParams.z));
+#elif GLINT_FOG_MODE == 3
+    float fogDistance = v_FogCoord * u_FogParams.w;
+    float fog = exp2(-(fogDistance * fogDistance));
+#endif
+#if GLINT_FOG_MODE != 0
+    color.rgb = mix(u_FogColor.rgb, color.rgb, clamp(fog, 0.0, 1.0));
+#endif
+    return color;
+}
+
+void main() {
+    bool visible0, visible1;
+    vec4 a = glintLayer(v_TexCoord0, visible0);
+    vec4 b = glintLayer(u_TextureMatrix3 * v_TexCoord0, visible1);
+    if (!visible0 && !visible1) discard;
+    fragColor = sqrt(a * a + b * b);
+#if GLINT_REPLACE_ALPHA
+    fragColor.a = visible1 ? b.a : a.a;
+#endif
+}

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/CompatUniformManagerTest.java

@@ -68,7 +68,7 @@ class CompatUniformManagerTest {
 
         // Use program and upload — should not error
         GL20.glUseProgram(program);
-        CompatUniformManager.refreshCompatUniforms(program);
+        CompatUniformManager.refreshCompatUniforms(program, GLStateManager.ctx());
 
         // Verify no GL errors
         assertEquals(0, GL11.glGetError(), "GL error after uniform upload");
@@ -146,7 +146,7 @@ class CompatUniformManagerTest {
 
         // Use program and upload — should not error
         GL20.glUseProgram(program);
-        CompatUniformManager.refreshCompatUniforms(program);
+        CompatUniformManager.refreshCompatUniforms(program, GLStateManager.ctx());
 
         assertEquals(0, GL11.glGetError(), "GL error after fog uniform upload");
     }

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/DisplayListIdAllocatorTest.java

@@ -1,7 +1,11 @@
 package com.gtnewhorizons.angelica.glsm;
 
+import com.gtnewhorizons.angelica.glsm.testutil.TestThreads;
+
 import java.util.HashSet;
 import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -12,6 +16,28 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class DisplayListIdAllocatorTest {
 
+    @Test
+    void concurrentAllocationsRemainUnique() throws Exception {
+        final DisplayListIDAllocator alloc = new DisplayListIDAllocator();
+        final int[][] ids = new int[2][500];
+        final CountDownLatch start = new CountDownLatch(1);
+        final TestThreads.Worker[] workers = new TestThreads.Worker[2];
+        for (int t = 0; t < workers.length; t++) {
+            final int[] lane = ids[t];
+            workers[t] = TestThreads.start("DisplayListIdAllocator-" + t, () -> {
+                if (!start.await(5, TimeUnit.SECONDS)) throw new AssertionError("start timed out");
+                for (int i = 0; i < lane.length; i++) lane[i] = alloc.allocRange(1);
+            });
+        }
+        start.countDown();
+        for (TestThreads.Worker worker : workers) worker.join();
+        final Set<Integer> unique = new HashSet<>();
+        for (int[] lane : ids) {
+            for (int id : lane) assertTrue(unique.add(id));
+        }
+        assertEquals(1000, unique.size());
+    }
+
     @Test
     void zeroNeverReturned() {
         DisplayListIDAllocator alloc = new DisplayListIDAllocator(1);

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/DrawableContexts.java

@@ -0,0 +1,38 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.testutil.Reflect;
+import com.gtnewhorizons.angelica.glsm.testutil.TestThreads;
+import org.lwjgl.opengl.SharedDrawable;
+
+import java.util.Arrays;
+import java.util.Map;
+
+final class DrawableContexts {
+
+    private DrawableContexts() {}
+
+    static TestThreads.Worker start(SharedDrawable drawable, String name, TestThreads.Body body) {
+        return TestThreads.start(name, () -> {
+            GLStateManager.makeCurrent(drawable);
+            try {
+                body.run();
+            } finally {
+                GLStateManager.releaseContext(drawable);
+            }
+        });
+    }
+
+    static void run(SharedDrawable drawable, String name, TestThreads.Body body) throws InterruptedException {
+        start(drawable, name, body).join();
+    }
+
+    static void destroy(SharedDrawable drawable) {
+        final Map<Object, GLContextState> contexts = Reflect.getStatic(GLStateManager.class, "drawableContexts");
+        final GLContextState ctx = contexts.remove(drawable);
+        if (ctx != null) {
+            final GLContextState[] states = Reflect.getStatic(GLStateManager.class, "drawableContextStates");
+            Reflect.setStatic(GLStateManager.class, "drawableContextStates", Arrays.stream(states).filter(s -> s != ctx).toArray(GLContextState[]::new));
+        }
+        drawable.destroy();
+    }
+}

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/GLSM_DisplayList_StateSet_GLTest.java

@@ -0,0 +1,305 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.recording.CompiledDisplayList;
+import com.gtnewhorizons.angelica.glsm.recording.GLCommand;
+import it.unimi.dsi.fastutil.ints.Int2IntMap;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL13;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static com.gtnewhorizons.angelica.util.GLSMUtil.verifyIsEnabled;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+@GLCoreTest
+public class GLSM_DisplayList_StateSet_GLTest {
+
+    private final List<Integer> listsToDelete = new ArrayList<>();
+
+    @AfterEach
+    void cleanup() {
+        DisplayListManager.abortCompilation();
+        while (GLStateManager.getAttribDepth() > 0) {
+            GLStateManager.popState();
+        }
+        for (int id : listsToDelete) {
+            GLStateManager.glDeleteLists(id, 1);
+        }
+        listsToDelete.clear();
+        GLStateManager.disableBlend();
+        GLStateManager.disableCull();
+        GLStateManager.glCullFace(GL11.GL_BACK);
+        GLStateManager.disableAlphaTest();
+        GLStateManager.glAlphaFunc(GL11.GL_ALWAYS, 0.0f);
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+        GLStateManager.disableTexture();
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+    }
+
+    private int newList() {
+        final int id = GLStateManager.glGenLists(1);
+        listsToDelete.add(id);
+        return id;
+    }
+
+    private static Int2IntMap commandCounts(int listId) {
+        final CompiledDisplayList compiled = DisplayListManager.getDisplayList(listId);
+        assertNotNull(compiled, "compiled display list must exist for id " + listId);
+        return compiled.getCommandCounts();
+    }
+
+    @Test
+    void compileBracketDoesNotThrowAndLeavesLiveStateUntouched() {
+        GLStateManager.enableAlphaTest();
+        GLStateManager.glAlphaFunc(GL11.GL_GREATER, 0.5f);
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+
+        final int func0 = GLStateManager.getAlphaState().getFunction();
+        final float ref0 = GLStateManager.getAlphaState().getReference();
+        final int unit0 = GLStateManager.getActiveTextureUnit();
+        final int depth0 = GLStateManager.getAttribDepth();
+
+        final int list = newList();
+        GLStateManager.glNewList(list, GL11.GL_COMPILE);
+        final int d = GLStateManager.pushState(StateSet.CUTOUT);
+        GLStateManager.enableAlphaTest();
+        GLStateManager.glAlphaFunc(GL11.GL_GREATER, 0.1f);
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+        GLStateManager.enableTexture();
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+        GLStateManager.popStateTo(d);
+        GLStateManager.glEndList();
+
+        verifyIsEnabled(GL11.GL_ALPHA_TEST, true, "cache alpha test enable unchanged after COMPILE-only bracket");
+        assertEquals(func0, GLStateManager.getAlphaState().getFunction(), "cache alpha func unchanged after COMPILE-only bracket");
+        assertEquals(ref0, GLStateManager.getAlphaState().getReference(), 0.0001f, "cache alpha ref unchanged after COMPILE-only bracket");
+        assertEquals(unit0, GLStateManager.getActiveTextureUnit(), "cache active unit unchanged after COMPILE-only bracket");
+        assertEquals(depth0, GLStateManager.getAttribDepth(), "live attrib depth unchanged after COMPILE-only bracket");
+        assertEquals(2, commandCounts(list).getOrDefault(GLCommand.COMPLEX_REF, 0), "push and pop each record one COMPLEX_REF");
+    }
+
+    @Test
+    void compiledBracketReplayRestoresState() {
+        final int list = newList();
+        GLStateManager.glNewList(list, GL11.GL_COMPILE);
+        final int d = GLStateManager.pushState(StateSet.CUTOUT);
+        GLStateManager.enableAlphaTest();
+        GLStateManager.glAlphaFunc(GL11.GL_GREATER, 0.1f);
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+        GLStateManager.enableTexture();
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+        GLStateManager.popStateTo(d);
+        GLStateManager.glEndList();
+
+        GLStateManager.glAlphaFunc(GL11.GL_LESS, 0.9f);
+        GLStateManager.disableAlphaTest();
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+        final int depth0 = GLStateManager.getAttribDepth();
+
+        GLStateManager.glCallList(list);
+
+        assertEquals(GL11.GL_LESS, GLStateManager.getAlphaState().getFunction(), "cache alpha func restored by replay");
+        assertEquals(0.9f, GLStateManager.getAlphaState().getReference(), 0.0001f, "cache alpha ref restored by replay");
+        verifyIsEnabled(GL11.GL_ALPHA_TEST, false, "cache alpha test restored disabled by replay");
+        assertEquals(0, GLStateManager.getActiveTextureUnit(), "cache active unit restored by replay");
+        assertEquals(GL13.GL_TEXTURE0, GL11.glGetInteger(GL13.GL_ACTIVE_TEXTURE), "driver active unit restored by replay");
+        assertEquals(depth0, GLStateManager.getAttribDepth(), "live attrib depth unchanged by balanced replay");
+    }
+
+    @Test
+    void compileAndExecuteBracketIsBalanced() {
+        GLStateManager.glAlphaFunc(GL11.GL_LESS, 0.9f);
+        GLStateManager.disableAlphaTest();
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+        final int depth0 = GLStateManager.getAttribDepth();
+
+        final int list = newList();
+        GLStateManager.glNewList(list, GL11.GL_COMPILE_AND_EXECUTE);
+        final int d = GLStateManager.pushState(StateSet.CUTOUT);
+        GLStateManager.enableAlphaTest();
+        GLStateManager.glAlphaFunc(GL11.GL_GREATER, 0.1f);
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+        GLStateManager.enableTexture();
+        GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+        GLStateManager.popStateTo(d);
+        GLStateManager.glEndList();
+
+        assertEquals(GL11.GL_LESS, GLStateManager.getAlphaState().getFunction(), "cache alpha func restored after GL_COMPILE_AND_EXECUTE bracket");
+        assertEquals(0.9f, GLStateManager.getAlphaState().getReference(), 0.0001f, "cache alpha ref restored after GL_COMPILE_AND_EXECUTE bracket");
+        verifyIsEnabled(GL11.GL_ALPHA_TEST, false, "cache alpha test restored disabled after GL_COMPILE_AND_EXECUTE bracket");
+        assertEquals(0, GLStateManager.getActiveTextureUnit(), "cache active unit restored after GL_COMPILE_AND_EXECUTE bracket");
+        assertEquals(depth0, GLStateManager.getAttribDepth(), "live attrib depth unchanged after balanced GL_COMPILE_AND_EXECUTE bracket");
+
+        GLStateManager.glCallList(list);
+        GLStateManager.glCallList(list);
+
+        assertEquals(GL11.GL_LESS, GLStateManager.getAlphaState().getFunction(), "cache alpha func restored after replay");
+        assertEquals(0.9f, GLStateManager.getAlphaState().getReference(), 0.0001f, "cache alpha ref restored after replay");
+        verifyIsEnabled(GL11.GL_ALPHA_TEST, false, "cache alpha test restored disabled after replay");
+        assertEquals(0, GLStateManager.getActiveTextureUnit(), "cache active unit restored after replay");
+        assertEquals(depth0, GLStateManager.getAttribDepth(), "live attrib depth unchanged after replay");
+    }
+
+    @Test
+    void nestedListsPushInBothLevels() {
+        GLStateManager.enableBlend();
+        GLStateManager.enableCull();
+        GLStateManager.glCullFace(GL11.GL_BACK);
+        final boolean cull0 = GLStateManager.glIsEnabled(GL11.GL_CULL_FACE);
+        final int depth0 = GLStateManager.getAttribDepth();
+
+        final int parent = newList();
+        final int child = newList();
+
+        GLStateManager.glNewList(parent, GL11.GL_COMPILE);
+        final int dParent = GLStateManager.pushState(StateSet.BLEND);
+        GLStateManager.glNewList(child, GL11.GL_COMPILE);
+        final int dChild = GLStateManager.pushState(StateSet.CULL);
+        if (cull0) {
+            GLStateManager.disableCull();
+        } else {
+            GLStateManager.enableCull();
+        }
+        GLStateManager.popStateTo(dChild);
+        GLStateManager.glEndList();
+        GLStateManager.disableBlend();
+        GLStateManager.popStateTo(dParent);
+        GLStateManager.glEndList();
+
+        assertEquals(depth0, GLStateManager.getAttribDepth(), "live attrib depth unchanged by nested COMPILE-only bracket");
+
+        GLStateManager.glCallList(parent);
+        verifyIsEnabled(GL11.GL_BLEND, true, "blend enable restored by the parent BLEND bracket after parent replay");
+        verifyIsEnabled(GL11.GL_CULL_FACE, cull0, "cull enable restored after parent replay");
+
+        GLStateManager.glCallList(child);
+        verifyIsEnabled(GL11.GL_CULL_FACE, cull0, "cull enable restored after child replay");
+    }
+
+    @Test
+    void nestedCompileAndExecuteChildInsideCompileParent() {
+        GLStateManager.enableCull();
+        GLStateManager.glCullFace(GL11.GL_BACK);
+        final boolean cull0 = GLStateManager.glIsEnabled(GL11.GL_CULL_FACE);
+        final int depth0 = GLStateManager.getAttribDepth();
+
+        final int parent = newList();
+        final int child = newList();
+
+        GLStateManager.glNewList(parent, GL11.GL_COMPILE);
+        final int dParent = GLStateManager.pushState(StateSet.BLEND);
+
+        GLStateManager.glNewList(child, GL11.GL_COMPILE_AND_EXECUTE);
+        final int dChild = GLStateManager.pushState(StateSet.CULL);
+        if (cull0) {
+            GLStateManager.disableCull();
+        } else {
+            GLStateManager.enableCull();
+        }
+        GLStateManager.popStateTo(dChild);
+        GLStateManager.glEndList();
+
+        verifyIsEnabled(GL11.GL_CULL_FACE, cull0, "cull enable restored live immediately after the COMPILE_AND_EXECUTE child bracket closes");
+
+        GLStateManager.popStateTo(dParent);
+        GLStateManager.glEndList();
+
+        assertEquals(depth0, GLStateManager.getAttribDepth(), "live attrib depth unchanged after balanced nested bracket");
+        assertEquals(2, commandCounts(parent).getOrDefault(GLCommand.COMPLEX_REF, 0), "parent list records exactly the BLEND push and pop");
+        assertEquals(2, commandCounts(child).getOrDefault(GLCommand.COMPLEX_REF, 0), "child list records exactly the CULL push and pop");
+    }
+
+    @Test
+    void unbalancedBracketIsClosedAtEndList() {
+        GLStateManager.enableBlend();
+        final boolean blend0 = GLStateManager.glIsEnabled(GL11.GL_BLEND);
+        final int depth0 = GLStateManager.getAttribDepth();
+
+        final int list = newList();
+        GLStateManager.glNewList(list, GL11.GL_COMPILE);
+        GLStateManager.pushState(StateSet.BATCH);
+        GLStateManager.disableBlend();
+        GLStateManager.glEndList();
+
+        assertEquals(2, commandCounts(list).getOrDefault(GLCommand.COMPLEX_REF, 0), "glEndList closes the unbalanced push, recording a matching pop");
+
+        GLStateManager.glCallList(list);
+        assertEquals(depth0, GLStateManager.getAttribDepth(), "live attrib depth unchanged after replaying an auto-closed bracket");
+        verifyIsEnabled(GL11.GL_BLEND, blend0, "blend enable unchanged after replaying an auto-closed bracket");
+
+        final int other = newList();
+        assertDoesNotThrow(() -> {
+            GLStateManager.glNewList(other, GL11.GL_COMPILE);
+            GLStateManager.glEndList();
+        }, "an unrelated list must compile normally after an auto-closed bracket");
+    }
+
+    @Test
+    void glPushAttribRecordsExactlyOnce() {
+        final int list = newList();
+        GLStateManager.glNewList(list, GL11.GL_COMPILE);
+        GLStateManager.glPushAttrib(GL11.GL_ENABLE_BIT);
+        GLStateManager.glPopAttrib();
+        GLStateManager.glEndList();
+
+        final Int2IntMap counts = commandCounts(list);
+        assertEquals(1, counts.getOrDefault(GLCommand.PUSH_ATTRIB, 0), "glPushAttrib records exactly one PUSH_ATTRIB opcode");
+        assertEquals(1, counts.getOrDefault(GLCommand.POP_ATTRIB, 0), "glPopAttrib records exactly one POP_ATTRIB opcode");
+        assertEquals(0, counts.getOrDefault(GLCommand.COMPLEX_REF, 0), "glPushAttrib/glPopAttrib never record a COMPLEX_REF");
+    }
+
+    @Test
+    void livePushStraddlesOpenList() {
+        GLStateManager.enableBlend();
+        final int d = GLStateManager.pushState(StateSet.BLEND);
+        GLStateManager.disableBlend();
+
+        final int list = newList();
+        GLStateManager.glNewList(list, GL11.GL_COMPILE);
+        GLStateManager.glEndList();
+
+        GLStateManager.popStateTo(d);
+
+        assertEquals(d, GLStateManager.getAttribDepth(), "live attrib depth restored to the pre-bracket value");
+        verifyIsEnabled(GL11.GL_BLEND, true, "blend enable restored by the live pop that straddled the open-then-closed list");
+    }
+
+    @Test
+    void livePopInsideOpenListPopsLiveAndRecordsNothing() {
+        GLStateManager.enableBlend();
+        final int d = GLStateManager.pushState(StateSet.BLEND);
+        GLStateManager.disableBlend();
+
+        final int list = newList();
+        GLStateManager.glNewList(list, GL11.GL_COMPILE);
+        GLStateManager.popStateTo(d);
+        GLStateManager.glEndList();
+
+        assertEquals(d, GLStateManager.getAttribDepth(), "live attrib depth restored by the live pop performed inside the open list");
+        verifyIsEnabled(GL11.GL_BLEND, true, "blend enable restored live by the pop of a pre-list push");
+        assertEquals(0, commandCounts(list).getOrDefault(GLCommand.COMPLEX_REF, 0), "popping a pre-existing live push records nothing into the list");
+    }
+
+    @Test
+    void virtualDepthOverflowThrowsAtRecordTime() {
+        final int startDepth = GLStateManager.getAttribDepth();
+        final int list = newList();
+        GLStateManager.glNewList(list, GL11.GL_COMPILE);
+
+        final int pushes = GLStateManager.MAX_ATTRIB_STACK_DEPTH - startDepth;
+        for (int i = 0; i < pushes; i++) {
+            GLStateManager.pushState(StateSet.CUTOUT);
+        }
+        assertThrows(IllegalStateException.class, () -> GLStateManager.pushState(StateSet.CUTOUT), "virtual depth overflow beyond MAX_ATTRIB_STACK_DEPTH must throw at record time");
+
+        DisplayListManager.abortCompilation();
+
+        assertEquals(startDepth, GLStateManager.getAttribDepth(), "aborting the overflowed compilation leaves live attrib depth untouched");
+    }
+}

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/GLSM_PopAttribMaskFidelity_GLTest.java

@@ -0,0 +1,252 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.stacks.BooleanStateStack;
+import org.junit.jupiter.api.Test;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL30;
+
+import static com.gtnewhorizons.angelica.util.GLSMUtil.verifyIsEnabled;
+import static com.gtnewhorizons.angelica.util.GLSMUtil.verifyState;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+@GLCoreTest
+public class GLSM_PopAttribMaskFidelity_GLTest {
+
+    private static int scanClipPlaneMask() {
+        final BooleanStateStack[] planes = GLStateManager.getClipPlaneStates();
+        int mask = 0;
+        for (int i = 0; i < planes.length; i++) {
+            if (planes[i].isEnabled()) mask |= (1 << i);
+        }
+        return mask;
+    }
+
+    private static void verifyClipPlaneMask(String message) {
+        final int scanned = scanClipPlaneMask();
+        assertEquals(scanned, GLStateManager.ctx().clipPlaneEnabledMask, message + " - mask mismatch");
+        assertEquals(scanned != 0, GLStateManager.anyClipPlaneEnabled(), message + " - anyClipPlaneEnabled mismatch");
+    }
+
+    @Test
+    void colorBufferBitDoesNotRestoreCull() {
+        try {
+            verifyIsEnabled(GL11.GL_CULL_FACE, false, "Cull - Initial");
+
+            GLStateManager.glPushAttrib(GL11.GL_COLOR_BUFFER_BIT);
+            GLStateManager.glEnable(GL11.GL_CULL_FACE);
+            GLStateManager.glPopAttrib();
+
+            verifyIsEnabled(GL11.GL_CULL_FACE, true, "Cull - Not a GL_COLOR_BUFFER_BIT member, must stay toggled");
+        } finally {
+            GLStateManager.glDisable(GL11.GL_CULL_FACE);
+        }
+    }
+
+    @Test
+    void enableBitRestoresCull() {
+        try {
+            verifyIsEnabled(GL11.GL_CULL_FACE, false, "Cull - Initial");
+
+            GLStateManager.glPushAttrib(GL11.GL_ENABLE_BIT);
+            GLStateManager.glEnable(GL11.GL_CULL_FACE);
+            verifyIsEnabled(GL11.GL_CULL_FACE, true, "Cull - After enable");
+            GLStateManager.glPopAttrib();
+
+            verifyIsEnabled(GL11.GL_CULL_FACE, false, "Cull - GL_ENABLE_BIT member, must restore");
+        } finally {
+            GLStateManager.glDisable(GL11.GL_CULL_FACE);
+        }
+    }
+
+    @Test
+    void innerNonMemberPopKeepsChange_OuterMemberPopRestores() {
+        try {
+            verifyIsEnabled(GL11.GL_CULL_FACE, false, "Cull - Initial");
+
+            GLStateManager.glPushAttrib(GL11.GL_ENABLE_BIT);
+            GLStateManager.glPushAttrib(GL11.GL_COLOR_BUFFER_BIT);
+            GLStateManager.glEnable(GL11.GL_CULL_FACE);
+            verifyIsEnabled(GL11.GL_CULL_FACE, true, "Cull - After enable inside inner bracket");
+
+            GLStateManager.glPopAttrib();
+            verifyIsEnabled(GL11.GL_CULL_FACE, true, "Cull - Inner pop is not a member, must stay toggled");
+
+            GLStateManager.glPopAttrib();
+            verifyIsEnabled(GL11.GL_CULL_FACE, false, "Cull - Outer pop is a member, must restore to pre-inner value");
+        } finally {
+            GLStateManager.glDisable(GL11.GL_CULL_FACE);
+        }
+    }
+
+    @Test
+    void modifyBeforeInnerPush_SurvivesInnerNonMemberPop() {
+        try {
+            verifyIsEnabled(GL11.GL_CULL_FACE, false, "Cull - Initial");
+
+            GLStateManager.glPushAttrib(GL11.GL_ENABLE_BIT);
+            GLStateManager.glEnable(GL11.GL_CULL_FACE);
+            verifyIsEnabled(GL11.GL_CULL_FACE, true, "Cull - After enable at outer depth");
+
+            GLStateManager.glPushAttrib(GL11.GL_COLOR_BUFFER_BIT);
+            GLStateManager.glPopAttrib();
+            verifyIsEnabled(GL11.GL_CULL_FACE, true, "Cull - Inner pop is not a member, must stay toggled");
+
+            GLStateManager.glPopAttrib();
+            verifyIsEnabled(GL11.GL_CULL_FACE, false, "Cull - Outer pop is a member, must restore");
+        } finally {
+            GLStateManager.glDisable(GL11.GL_CULL_FACE);
+        }
+    }
+
+    @Test
+    void twoModifiesAtOneDepthRestoreOnce() {
+        try {
+            verifyIsEnabled(GL11.GL_BLEND, false, "Blend - Initial");
+
+            GLStateManager.glPushAttrib(GL11.GL_COLOR_BUFFER_BIT);
+            GLStateManager.glEnable(GL11.GL_BLEND);
+            GLStateManager.glDisable(GL11.GL_BLEND);
+            GLStateManager.glEnable(GL11.GL_BLEND);
+            verifyIsEnabled(GL11.GL_BLEND, true, "Blend - After multiple toggles at one depth");
+
+            GLStateManager.glPopAttrib();
+            verifyIsEnabled(GL11.GL_BLEND, false, "Blend - GL_COLOR_BUFFER_BIT member, must restore original");
+        } finally {
+            GLStateManager.glDisable(GL11.GL_BLEND);
+        }
+    }
+
+    @Test
+    void lightingBitRestoresLightingAndLightEnables() {
+        try {
+            verifyIsEnabled(GL11.GL_LIGHTING, false, "Lighting - Initial");
+            verifyIsEnabled(GL11.GL_LIGHT0, false, "Light0 - Initial");
+
+            GLStateManager.glPushAttrib(GL11.GL_LIGHTING_BIT);
+            GLStateManager.glEnable(GL11.GL_LIGHTING);
+            GLStateManager.glEnable(GL11.GL_LIGHT0);
+            verifyIsEnabled(GL11.GL_LIGHTING, true, "Lighting - After enable");
+            verifyIsEnabled(GL11.GL_LIGHT0, true, "Light0 - After enable");
+
+            GLStateManager.glPopAttrib();
+            verifyIsEnabled(GL11.GL_LIGHTING, false, "Lighting - GL_LIGHTING_BIT member, must restore");
+            verifyIsEnabled(GL11.GL_LIGHT0, false, "Light0 - GL_LIGHTING_BIT member, must restore");
+        } finally {
+            GLStateManager.glDisable(GL11.GL_LIGHTING);
+            GLStateManager.glDisable(GL11.GL_LIGHT0);
+        }
+    }
+
+    @Test
+    void enableDisableTracksClipPlaneMask() {
+        try {
+            verifyClipPlaneMask("Initial");
+
+            GLStateManager.glEnable(GL11.GL_CLIP_PLANE0);
+            verifyIsEnabled(GL11.GL_CLIP_PLANE0, true, "Clip0 - After enable");
+            verifyClipPlaneMask("After enable");
+
+            GLStateManager.glDisable(GL11.GL_CLIP_PLANE0);
+            verifyIsEnabled(GL11.GL_CLIP_PLANE0, false, "Clip0 - After disable");
+            verifyClipPlaneMask("After disable");
+        } finally {
+            GLStateManager.glDisable(GL11.GL_CLIP_PLANE0);
+        }
+    }
+
+    @Test
+    void transformBitPopRestoresClipPlaneAndMask() {
+        try {
+            verifyClipPlaneMask("Initial");
+
+            GLStateManager.glPushAttrib(GL11.GL_TRANSFORM_BIT);
+            GLStateManager.glEnable(GL11.GL_CLIP_PLANE1);
+            verifyIsEnabled(GL11.GL_CLIP_PLANE1, true, "Clip1 - After enable inside GL_TRANSFORM_BIT");
+            verifyClipPlaneMask("After enable inside GL_TRANSFORM_BIT");
+
+            GLStateManager.glPopAttrib();
+            verifyIsEnabled(GL11.GL_CLIP_PLANE1, false, "Clip1 - GL_TRANSFORM_BIT member, must restore");
+            verifyClipPlaneMask("After GL_TRANSFORM_BIT pop");
+        } finally {
+            GLStateManager.glDisable(GL11.GL_CLIP_PLANE1);
+        }
+    }
+
+    @Test
+    void scissorBoxFollowsScissorBitOnly() {
+        final int[] boxA = { 10, 20, 100, 200 };
+        final int[] boxB = { 30, 40, 50, 60 };
+        try {
+            GLStateManager.glScissor(boxA[0], boxA[1], boxA[2], boxA[3]);
+            GLStateManager.disableScissorTest();
+            verifyState(GL11.GL_SCISSOR_BOX, boxA, "Scissor box - Initial");
+            verifyIsEnabled(GL11.GL_SCISSOR_TEST, false, "Scissor - Initial");
+
+            GLStateManager.glPushAttrib(GL11.GL_SCISSOR_BIT);
+            GLStateManager.enableScissorTest();
+            GLStateManager.glScissor(boxB[0], boxB[1], boxB[2], boxB[3]);
+            GLStateManager.glPopAttrib();
+
+            verifyState(GL11.GL_SCISSOR_BOX, boxA, "Scissor box - GL_SCISSOR_BIT member, must restore");
+            verifyIsEnabled(GL11.GL_SCISSOR_TEST, false, "Scissor - GL_SCISSOR_BIT member, must restore");
+
+            GLStateManager.glPushAttrib(GL11.GL_ENABLE_BIT);
+            GLStateManager.enableScissorTest();
+            GLStateManager.glScissor(boxB[0], boxB[1], boxB[2], boxB[3]);
+            GLStateManager.glPopAttrib();
+
+            verifyState(GL11.GL_SCISSOR_BOX, boxB, "Scissor box - Not a GL_ENABLE_BIT member, must stay changed");
+            verifyIsEnabled(GL11.GL_SCISSOR_TEST, false, "Scissor - GL_ENABLE_BIT member, must restore");
+        } finally {
+            GLStateManager.disableScissorTest();
+            GLStateManager.glScissor(0, 0, 800, 600);
+        }
+    }
+
+    @Test
+    void rasterizerDiscardIsNotAnEnableBitMember() {
+        try {
+            verifyIsEnabled(GL30.GL_RASTERIZER_DISCARD, false, "RasterizerDiscard - Initial");
+
+            GLStateManager.glEnable(GL30.GL_RASTERIZER_DISCARD);
+            verifyIsEnabled(GL30.GL_RASTERIZER_DISCARD, true, "RasterizerDiscard - After enable");
+
+            GLStateManager.glPushAttrib(GL11.GL_ENABLE_BIT);
+            GLStateManager.glDisable(GL30.GL_RASTERIZER_DISCARD);
+            verifyIsEnabled(GL30.GL_RASTERIZER_DISCARD, false, "RasterizerDiscard - After disable inside GL_ENABLE_BIT");
+            GLStateManager.glPopAttrib();
+
+            verifyIsEnabled(GL30.GL_RASTERIZER_DISCARD, false, "RasterizerDiscard - Not a GL_ENABLE_BIT member, must stay disabled");
+        } finally {
+            GLStateManager.glDisable(GL30.GL_RASTERIZER_DISCARD);
+        }
+    }
+
+    @Test
+    void clearDepthIsClamped() {
+        try {
+            GLStateManager.glClearDepth(2.0);
+            verifyState(GL11.GL_DEPTH_CLEAR_VALUE, 1.0f, "Depth clear value - glClearDepth(2.0) must clamp to 1.0");
+        } finally {
+            GLStateManager.glClearDepth(1.0);
+        }
+    }
+
+    @Test
+    void colorBufferBitPopDoesNotRestoreClipPlaneButMaskStaysFaithful() {
+        try {
+            verifyClipPlaneMask("Initial");
+
+            GLStateManager.glPushAttrib(GL11.GL_COLOR_BUFFER_BIT);
+            GLStateManager.glEnable(GL11.GL_CLIP_PLANE2);
+            verifyIsEnabled(GL11.GL_CLIP_PLANE2, true, "Clip2 - After enable inside GL_COLOR_BUFFER_BIT");
+            verifyClipPlaneMask("After enable inside GL_COLOR_BUFFER_BIT");
+
+            GLStateManager.glPopAttrib();
+            verifyIsEnabled(GL11.GL_CLIP_PLANE2, true, "Clip2 - Not a GL_COLOR_BUFFER_BIT member, must stay toggled");
+            verifyClipPlaneMask("After GL_COLOR_BUFFER_BIT pop");
+        } finally {
+            GLStateManager.glDisable(GL11.GL_CLIP_PLANE2);
+        }
+    }
+}

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/GLSM_ServerSideState_UnitTest.java

@@ -15,6 +15,7 @@ import java.util.concurrent.TimeUnit;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
@@ -37,7 +38,10 @@ public class GLSM_ServerSideState_UnitTest {
     private Runnable pendingCommand;
     private Throwable backgroundError;
     private volatile boolean shutdownRequested;
+    private volatile GLContextState workerContext;
+    private volatile boolean workerCaching;
     private boolean originalSplashComplete;
+    private Thread originalDrawableGLHolder;
 
     private static void setSplashComplete(boolean value) {
         SplashWindow.setSplashComplete(value);
@@ -50,6 +54,7 @@ public class GLSM_ServerSideState_UnitTest {
     @BeforeEach
     void setupSharedDrawable() throws Exception {
         originalSplashComplete = getSplashComplete();
+        originalDrawableGLHolder = GLStateManager.getDrawableGLHolder();
 
         // Reset splash state to simulate splash screen scenario
         setSplashComplete(false);
@@ -67,6 +72,8 @@ public class GLSM_ServerSideState_UnitTest {
 
         shutdownRequested = false;
         backgroundError = null;
+        workerContext = null;
+        workerCaching = false;
         initLatch = new CountDownLatch(1);
         commandLatch = new CountDownLatch(1);
         completeLatch = new CountDownLatch(1);
@@ -75,10 +82,8 @@ public class GLSM_ServerSideState_UnitTest {
         backgroundThread = new Thread(() -> {
             try {
                 GLStateManager.makeCurrent(sharedDrawable);
-
-                if (GLStateManager.isCachingEnabled()) {
-                    throw new AssertionError("SharedDrawable thread should have caching DISABLED");
-                }
+                workerContext = GLStateManager.ctx();
+                workerCaching = GLStateManager.isCachingEnabled();
 
                 // Signal that initialization is complete
                 initLatch.countDown();
@@ -102,11 +107,12 @@ public class GLSM_ServerSideState_UnitTest {
                 }
             } catch (InterruptedException e) {
                 // Normal shutdown
-            } catch (LWJGLException e) {
-                backgroundError = e;
+            } catch (Throwable t) {
+                backgroundError = t;
+                initLatch.countDown();
             } finally {
                 try {
-                    sharedDrawable.releaseContext();
+                    GLStateManager.releaseContext(sharedDrawable);
                 } catch (LWJGLException e) {
                     // Ignore on cleanup
                 }
@@ -116,6 +122,11 @@ public class GLSM_ServerSideState_UnitTest {
 
         // Wait for background thread to complete initialization
         assertTrue(initLatch.await(5, TimeUnit.SECONDS), "Background thread failed to initialize");
+        if (backgroundError != null) {
+            fail("Background thread failed to make SharedDrawable current", backgroundError);
+        }
+        assertTrue(workerCaching, "SharedDrawable thread should cache into its own context");
+        assertNotSame(GLStateManager.ctx(), workerContext, "SharedDrawable thread must not share the main thread's context");
     }
 
     @AfterEach
@@ -132,11 +143,12 @@ public class GLSM_ServerSideState_UnitTest {
         }
 
         if (sharedDrawable != null) {
-            sharedDrawable.destroy();
+            DrawableContexts.destroy(sharedDrawable);
         }
 
         // Restore original state
         GLStateManager.setDrawableGL(null);
+        GLStateManager.setDrawableGLHolder(originalDrawableGLHolder);
         setSplashComplete(originalSplashComplete);
         if (originalSplashComplete) {
             GLStateManager.markSplashComplete("test");
@@ -328,7 +340,11 @@ public class GLSM_ServerSideState_UnitTest {
             GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texId1);
             assertEquals(texId1, GLStateManager.getBoundTextureForServerState(), "Main thread cache should show texId1 bound");
 
-            executeOnSharedDrawable(() -> GL11.glBindTexture(GL11.GL_TEXTURE_2D, texId2));
+            executeOnSharedDrawable(() -> {
+                GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texId2);
+                assertEquals(texId2, GLStateManager.getBoundTextureForServerState(), "SharedDrawable cache should show texId2 bound");
+                assertEquals(texId2, GL11.glGetInteger(GL11.GL_TEXTURE_BINDING_2D), "SharedDrawable actual GL binding should be texId2");
+            });
 
             assertEquals(texId1, GLStateManager.getBoundTextureForServerState(), "Main thread cache should still show texId1 (client-side state is per-context)");
 
@@ -436,38 +452,40 @@ public class GLSM_ServerSideState_UnitTest {
         }
     }
 
-    /**
-     * Test glDeleteTextures: SharedDrawable deletes texture, verify cache cleared.
-     */
     @Test
     void testDeleteTexturesFromSharedDrawable() throws InterruptedException {
-        int texId = GL11.glGenTextures();
+        final int texId = GLStateManager.glGenTextures();
+        int flushGen = 0;
 
         try {
             GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texId);
             GLStateManager.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_LINEAR);
             GLStateManager.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGBA, 32, 32, 0, GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, (ByteBuffer) null);
 
-            int cachedFilter = GLStateManager.glGetTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER);
-            assertEquals(GL11.GL_LINEAR, cachedFilter, "Cache should have LINEAR before delete");
-
+            assertEquals(GL11.GL_LINEAR, GLStateManager.glGetTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER), "Cache should have LINEAR before delete");
             assertTrue(GL11.glIsTexture(texId), "Texture should exist before delete");
 
-            // SharedDrawable: delete the texture (deferred — name stays valid)
             executeOnSharedDrawable(() -> {
+                GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texId);
                 GLStateManager.glDeleteTextures(texId);
+                assertEquals(0, GLStateManager.getBoundTextureForServerState(), "Delete should unbind from the deleting context");
                 assertTrue(GL11.glIsTexture(texId), "Texture name should still be valid (deferred delete)");
             });
 
-            assertTrue(GL11.glIsTexture(texId), "Texture name should still be valid on main thread (deferred delete)");
+            assertEquals(texId, GLStateManager.getBoundTextureForServerState(), "Main thread binding should survive until the flush");
 
-            // glGenTextures flushes deferred deletes
-            int newTexId = GLStateManager.glGenTextures();
-            assertFalse(GL11.glIsTexture(texId), "Texture should be gone after flush via glGenTextures");
-            GL11.glDeleteTextures(newTexId);
+            final int deferredGen = GLStateManager.glGenTextures();
+            GL11.glDeleteTextures(deferredGen);
+            assertTrue(GL11.glIsTexture(texId), "Delete should stay deferred while the splash is not complete");
+
+            setSplashComplete(true);
+            flushGen = GLStateManager.glGenTextures();
+            assertFalse(GL11.glIsTexture(texId), "Texture should be gone after the post-splash flush");
+            assertEquals(0, GLStateManager.getBoundTextureForServerState(), "Flush should scrub the main thread binding");
 
         } finally {
             GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, 0);
+            if (flushGen != 0) GL11.glDeleteTextures(flushGen);
             if (GL11.glIsTexture(texId)) {
                 GL11.glDeleteTextures(texId);
             }

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/GLSM_SharedDrawableContext_GLTest.java

@@ -0,0 +1,302 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.ffp.FfpFixture;
+import com.gtnewhorizons.angelica.glsm.ffp.ShaderManager;
+import com.gtnewhorizons.angelica.glsm.ffp.VAOManager;
+import com.gtnewhorizons.angelica.glsm.testutil.TestThreads;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.lwjgl.BufferUtils;
+import org.lwjgl.opengl.Display;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+import org.lwjgl.opengl.GL20;
+import org.lwjgl.opengl.GL30;
+import org.lwjgl.opengl.SharedDrawable;
+
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@GLCoreTest
+public class GLSM_SharedDrawableContext_GLTest {
+
+    private SharedDrawable sharedDrawable;
+
+    @AfterEach
+    void cleanup() {
+        if (sharedDrawable != null) {
+            DrawableContexts.destroy(sharedDrawable);
+            sharedDrawable = null;
+        }
+    }
+
+    @Test
+    void sharedDrawableBindsItsOwnContext() throws Exception {
+        final GLContextState primary = GLStateManager.ctx();
+        sharedDrawable = new SharedDrawable(Display.getDrawable());
+
+        TestThreads.run("SharedDrawableContext-Bind-Thread", () -> {
+            GLStateManager.makeCurrent(sharedDrawable);
+            try {
+                final GLContextState workerCtx = GLStateManager.ctx();
+                assertNotSame(primary, workerCtx);
+                assertNotEquals(0, workerCtx.defaultVAO);
+                assertEquals(workerCtx.defaultVAO, GL11.glGetInteger(GL30.GL_VERTEX_ARRAY_BINDING));
+
+                final IntBuffer viewport = BufferUtils.createIntBuffer(16);
+                GL11.glGetInteger(GL11.GL_VIEWPORT, viewport);
+                assertEquals(0, viewport.get(0));
+                assertEquals(0, viewport.get(1));
+                assertEquals(Display.getWidth(), viewport.get(2));
+                assertEquals(Display.getHeight(), viewport.get(3));
+            } finally {
+                GLStateManager.releaseContext(sharedDrawable);
+            }
+            assertSame(primary, GLStateManager.ctx());
+        });
+    }
+
+    @Test
+    void failedContextSwitchRestoresPreviousBinding() throws Exception {
+        final GLContextState primary = GLStateManager.ctx();
+        sharedDrawable = new SharedDrawable(Display.getDrawable());
+        final CountDownLatch acquired = new CountDownLatch(1);
+        final CountDownLatch release = new CountDownLatch(1);
+        final TestThreads.Worker worker = DrawableContexts.start(sharedDrawable, "SharedDrawableContext-Owner-Thread", () -> {
+            acquired.countDown();
+            if (!release.await(5, TimeUnit.SECONDS)) throw new AssertionError("release timed out");
+        });
+        try {
+            assertTrue(acquired.await(5, TimeUnit.SECONDS));
+            assertThrows(IllegalStateException.class, () -> GLStateManager.makeCurrent(sharedDrawable));
+            assertSame(primary, GLStateManager.ctx());
+            assertEquals(primary.defaultVAO, GL11.glGetInteger(GL30.GL_VERTEX_ARRAY_BINDING));
+        } finally {
+            release.countDown();
+            worker.join();
+        }
+        GLStateManager.makeCurrent(sharedDrawable);
+        assertNotSame(primary, GLStateManager.ctx());
+        GLStateManager.releaseContext(sharedDrawable);
+        GLStateManager.makeCurrent(Display.getDrawable());
+        assertSame(primary, GLStateManager.ctx());
+    }
+
+    @Test
+    void foreignThreadCannotFinishOrRecordIntoActiveList() throws Exception {
+        sharedDrawable = new SharedDrawable(Display.getDrawable());
+        final int existing = GLStateManager.glGenLists(1);
+        final int active = GLStateManager.glGenLists(1);
+        final int rejected = GLStateManager.glGenLists(1);
+        GLStateManager.glNewList(existing, GL11.GL_COMPILE);
+        GLStateManager.enableBlend();
+        GLStateManager.glEndList();
+        GLStateManager.disableBlend();
+
+        final CountDownLatch started = new CountDownLatch(1);
+        final CountDownLatch finish = new CountDownLatch(1);
+        final TestThreads.Worker worker = DrawableContexts.start(sharedDrawable, "SharedDrawableContext-List-Thread", () -> {
+            GLStateManager.glNewList(active, GL11.GL_COMPILE);
+            started.countDown();
+            if (!finish.await(5, TimeUnit.SECONDS)) throw new AssertionError("finish timed out");
+            GLStateManager.glEndList();
+        });
+        try {
+            try {
+                assertTrue(started.await(5, TimeUnit.SECONDS));
+                assertThrows(IllegalStateException.class, () -> GLStateManager.glNewList(rejected, GL11.GL_COMPILE));
+                assertThrows(IllegalStateException.class, GLStateManager::glEndList);
+                assertEquals(0, GLStateManager.getListMode());
+                DisplayListManager.abortIfLeaked();
+                assertThrows(IllegalStateException.class, DisplayListManager::abortCompilation);
+                GLStateManager.glCallList(existing);
+                assertTrue(GLStateManager.glIsEnabled(GL11.GL_BLEND));
+                assertEquals(0, GLStateManager.getListMode());
+            } finally {
+                finish.countDown();
+                worker.join();
+            }
+            assertTrue(DisplayListManager.displayListExists(active));
+            GLStateManager.glCallList(active);
+        } finally {
+            GLStateManager.glDeleteLists(existing, 1);
+            GLStateManager.glDeleteLists(active, 1);
+            GLStateManager.glDeleteLists(rejected, 1);
+            GLStateManager.disableBlend();
+        }
+    }
+
+    @Test
+    void simultaneousListStartsClaimOneOwner() throws Exception {
+        sharedDrawable = new SharedDrawable(Display.getDrawable());
+        final int first = GLStateManager.glGenLists(1);
+        final int second = GLStateManager.glGenLists(1);
+        final CyclicBarrier start = new CyclicBarrier(2);
+        final CountDownLatch attempted = new CountDownLatch(2);
+        final AtomicInteger completed = new AtomicInteger();
+        final AtomicInteger rejected = new AtomicInteger();
+        final TestThreads.Worker worker = DrawableContexts.start(sharedDrawable, "SharedDrawableContext-List-Race-Thread", () -> {
+            start.await();
+            try {
+                GLStateManager.glNewList(second, GL11.GL_COMPILE);
+            } catch (IllegalStateException expected) {
+                rejected.incrementAndGet();
+                attempted.countDown();
+                return;
+            }
+            attempted.countDown();
+            if (!attempted.await(5, TimeUnit.SECONDS)) throw new AssertionError("attempts timed out");
+            GLStateManager.glEndList();
+            completed.incrementAndGet();
+        });
+        try {
+            start.await();
+            try {
+                GLStateManager.glNewList(first, GL11.GL_COMPILE);
+            } catch (IllegalStateException expected) {
+                rejected.incrementAndGet();
+                attempted.countDown();
+            }
+            if (GLStateManager.getListMode() != 0) {
+                attempted.countDown();
+                assertTrue(attempted.await(5, TimeUnit.SECONDS));
+                GLStateManager.glEndList();
+                completed.incrementAndGet();
+            }
+            worker.join();
+        } finally {
+            GLStateManager.glDeleteLists(first, 1);
+            GLStateManager.glDeleteLists(second, 1);
+        }
+        assertEquals(1, completed.get());
+        assertEquals(1, rejected.get());
+    }
+
+    @Test
+    void reenteredContextRebindsFfpProgram() throws Exception {
+        sharedDrawable = new SharedDrawable(Display.getDrawable());
+
+        DrawableContexts.run(sharedDrawable, "SharedDrawableContext-Reentry-Thread", () -> {
+            final ShaderManager sm = ShaderManager.getInstance();
+            final boolean wasEnabled = ShaderManager.isEnabled();
+            ShaderManager.enable();
+            sm.activate();
+            try {
+                final FloatBuffer vertices = BufferUtils.createFloatBuffer(9);
+                vertices.put(new float[] { -0.5f, -0.5f, 0f, 0.5f, -0.5f, 0f, 0f, 0.5f, 0f });
+                vertices.flip();
+                final int vbo = GLStateManager.glGenBuffers();
+                GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, vbo);
+                GLStateManager.glBufferData(GL15.GL_ARRAY_BUFFER, vertices, GL15.GL_STATIC_DRAW);
+                FfpFixture.attrib(0, 3, GL11.GL_FLOAT, false, 12, 0);
+                VAOManager.setCurrentVertexFlags(0);
+
+                GLStateManager.glDrawArrays(GL11.GL_TRIANGLES, 0, 3);
+
+                GLStateManager.releaseContext(sharedDrawable);
+                GLStateManager.makeCurrent(sharedDrawable);
+
+                GLStateManager.glDrawArrays(GL11.GL_TRIANGLES, 0, 3);
+
+                assertNotEquals(0, GL11.glGetInteger(GL20.GL_CURRENT_PROGRAM), "invalidateProgram must force a rebind after replay clears the program to 0");
+
+                GLStateManager.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);
+                GLStateManager.glDeleteBuffers(vbo);
+            } finally {
+                sm.deactivate();
+                if (!wasEnabled) ShaderManager.disable();
+            }
+        });
+    }
+
+    @Test
+    void deferredTextureDeletesWaitForSplashAndScrubDrawableContexts() throws Exception {
+        sharedDrawable = new SharedDrawable(Display.getDrawable());
+        final int t = GLStateManager.glGenTextures();
+
+        final AtomicReference<GLContextState> workerCtxRef = new AtomicReference<>();
+        DrawableContexts.run(sharedDrawable, "SharedDrawableContext-DeferredDelete-Thread", () -> {
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, t);
+            workerCtxRef.set(GLStateManager.ctx());
+        });
+
+        final GLContextState workerCtx = workerCtxRef.get();
+        int deferredGen = 0;
+        int flushGen = 0;
+
+        try {
+            SplashWindow.setSplashComplete(false);
+            GLStateManager.glDeleteTextures(t);
+            deferredGen = GLStateManager.glGenTextures();
+
+            assertTrue(GL11.glIsTexture(t), "delete must stay deferred while the splash is not complete");
+            assertEquals(t, workerCtx.textures.getTextureUnitBindings(0).getBinding(), "worker ctx binding must survive until the flush");
+
+            SplashWindow.setSplashComplete(true);
+            flushGen = GLStateManager.glGenTextures();
+
+            assertFalse(GL11.glIsTexture(t), "the flush must delete the texture once the splash is complete");
+            assertEquals(0, workerCtx.textures.getTextureUnitBindings(0).getBinding(), "the flush must scrub the drawable context's binding");
+        } finally {
+            SplashWindow.setSplashComplete(true);
+            if (deferredGen != 0) GL11.glDeleteTextures(deferredGen);
+            if (flushGen != 0) GL11.glDeleteTextures(flushGen);
+        }
+    }
+
+    @Test
+    void concurrentContextsDoNotShareAttribOrCurrentState() throws Exception {
+        final GLContextState primary = GLStateManager.ctx();
+        sharedDrawable = new SharedDrawable(Display.getDrawable());
+
+        final CyclicBarrier barrier = new CyclicBarrier(2);
+        final AtomicReference<GLContextState> workerCtxRef = new AtomicReference<>();
+        final TestThreads.Worker worker = DrawableContexts.start(sharedDrawable, "SharedDrawableContext-Concurrent-Thread", () -> {
+            workerCtxRef.set(GLStateManager.ctx());
+            barrier.await();
+            for (int i = 0; i < 20000; i++) {
+                final int t = GLStateManager.pushState(StateSet.FONT);
+                GLStateManager.glNormal3f(0.1f, 0.2f, 0.3f);
+                GLStateManager.popStateTo(t);
+            }
+            GLStateManager.glNormal3f(0.1f, 0.2f, 0.3f);
+        });
+
+        try {
+            barrier.await();
+            for (int i = 0; i < 20000; i++) {
+                final int t = GLStateManager.pushState(StateSet.FONT);
+                GLStateManager.glNormal3f(0.25f, 0.5f, 0.75f);
+                GLStateManager.popStateTo(t);
+            }
+            GLStateManager.glNormal3f(0.25f, 0.5f, 0.75f);
+            worker.join();
+
+            final GLContextState workerCtx = workerCtxRef.get();
+            assertNotSame(primary, workerCtx);
+            assertEquals(0, primary.attribDepth);
+            assertEquals(0, workerCtx.attribDepth);
+            assertEquals(0.25f, primary.ffp.currentNormal.x, 0.0f);
+            assertEquals(0.5f, primary.ffp.currentNormal.y, 0.0f);
+            assertEquals(0.75f, primary.ffp.currentNormal.z, 0.0f);
+            assertEquals(0.1f, workerCtx.ffp.currentNormal.x, 0.0f);
+            assertEquals(0.2f, workerCtx.ffp.currentNormal.y, 0.0f);
+            assertEquals(0.3f, workerCtx.ffp.currentNormal.z, 0.0f);
+        } finally {
+            GLStateManager.glNormal3f(0.0f, 0.0f, 1.0f);
+        }
+    }
+}

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/GLSM_SplashCompleteLatch_UnitTest.java

@@ -1,9 +1,14 @@
 package com.gtnewhorizons.angelica.glsm;
 
+import com.gtnewhorizons.angelica.glsm.testutil.Reflect;
+import com.gtnewhorizons.angelica.glsm.testutil.TestThreads;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.lwjgl.opengl.Display;
 
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.junit.jupiter.api.Assertions.assertFalse;
@@ -63,4 +68,37 @@ public class GLSM_SplashCompleteLatch_UnitTest {
         t.join();
         assertTrue(cachingOffThread.get(), "after the latch caching is global - this is what the latch buys");
     }
+
+    @Test
+    void pausedSplashThreadDoesNotCompleteUntilItExits() throws Exception {
+        final CountDownLatch released = new CountDownLatch(1);
+        final CountDownLatch resume = new CountDownLatch(1);
+
+        GLStateManager.releaseContext(Display.getDrawable());
+
+        try {
+            final TestThreads.Worker worker = TestThreads.start("SplashPause-Worker-Thread", () -> {
+                GLStateManager.makeCurrent(Display.getDrawable());
+                GLStateManager.releaseContext(Display.getDrawable());
+                released.countDown();
+                resume.await();
+            });
+            assertTrue(released.await(10, TimeUnit.SECONDS), "worker did not release the Display drawable in time");
+
+            GLStateManager.makeCurrent(Display.getDrawable());
+            assertFalse(GLStateManager.isSplashComplete());
+
+            resume.countDown();
+            worker.join();
+
+            GLStateManager.releaseContext(Display.getDrawable());
+            GLStateManager.makeCurrent(Display.getDrawable());
+            assertTrue(GLStateManager.isSplashComplete());
+        } finally {
+            resume.countDown();
+            Reflect.setStatic(GLStateManager.class, "stateSeedPending", false);
+            Reflect.setStatic(GLStateManager.class, "splashDisplayReleaser", null);
+            GLStateManager.makeCurrent(Display.getDrawable());
+        }
+    }
 }

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/GLSM_StateSet_GLTest.java

@@ -0,0 +1,709 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.ffp.ShaderManager;
+import org.junit.jupiter.api.Test;
+import org.lwjgl.BufferUtils;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL13;
+import org.lwjgl.opengl.GL14;
+import org.lwjgl.opengl.GL20;
+
+import java.nio.ByteBuffer;
+import java.nio.FloatBuffer;
+
+import static com.gtnewhorizons.angelica.util.GLSMUtil.verifyIsEnabled;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@GLCoreTest
+public class GLSM_StateSet_GLTest {
+
+    private static int driverTextureBinding(int unit) {
+        final int saved = GL11.glGetInteger(GL13.GL_ACTIVE_TEXTURE);
+        GL13.glActiveTexture(GL13.GL_TEXTURE0 + unit);
+        final int binding = GL11.glGetInteger(GL11.GL_TEXTURE_BINDING_2D);
+        GL13.glActiveTexture(saved);
+        return binding;
+    }
+
+    private static boolean[] driverColorWriteMask() {
+        final ByteBuffer buf = BufferUtils.createByteBuffer(16);
+        GL11.glGetBoolean(GL11.GL_COLOR_WRITEMASK, buf);
+        return new boolean[] { buf.get(0) != 0, buf.get(1) != 0, buf.get(2) != 0, buf.get(3) != 0 };
+    }
+
+    private static int compileShader(int type, String src) {
+        final int s = GL20.glCreateShader(type);
+        GL20.glShaderSource(s, src);
+        GL20.glCompileShader(s);
+        assertEquals(GL11.GL_TRUE, GL20.glGetShaderi(s, GL20.GL_COMPILE_STATUS), () -> "shader compile failed: " + GL20.glGetShaderInfoLog(s, 4096));
+        return s;
+    }
+
+    private static final String TRIVIAL_VS = "#version 330 core\nvoid main(){ gl_Position = vec4(0.0); }\n";
+    private static final String TRIVIAL_FS = "#version 330 core\nout vec4 o;\nvoid main(){ o = vec4(1.0); }\n";
+
+    private static int linkTrivialProgram() {
+        final int v = compileShader(GL20.GL_VERTEX_SHADER, TRIVIAL_VS);
+        final int f = compileShader(GL20.GL_FRAGMENT_SHADER, TRIVIAL_FS);
+        final int p = GL20.glCreateProgram();
+        GL20.glAttachShader(p, v);
+        GL20.glAttachShader(p, f);
+        GL20.glLinkProgram(p);
+        assertEquals(GL11.GL_TRUE, GL20.glGetProgrami(p, GL20.GL_LINK_STATUS), () -> "link failed: " + GL20.glGetProgramInfoLog(p, 4096));
+        GL20.glDeleteShader(v);
+        GL20.glDeleteShader(f);
+        return p;
+    }
+
+    @Test
+    void batchRestoresBlendAxisAndLightingBooleanButNotStencil() {
+        try {
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.disableLighting();
+            GLStateManager.glDisable(GL11.GL_STENCIL_TEST);
+
+            final int d = GLStateManager.pushState(StateSet.BATCH);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_DST_COLOR, GL11.GL_ZERO, GL11.GL_DST_COLOR, GL11.GL_ZERO);
+            GLStateManager.enableLighting();
+            GLStateManager.glEnable(GL11.GL_STENCIL_TEST);
+            GLStateManager.popStateTo(d);
+
+            verifyIsEnabled(GL11.GL_BLEND, true, "Blend enable - restored by BATCH pop");
+            assertEquals(GL11.GL_SRC_ALPHA, GL11.glGetInteger(GL14.GL_BLEND_SRC_RGB), "driver blend src rgb");
+            assertEquals(GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.glGetInteger(GL14.GL_BLEND_DST_RGB), "driver blend dst rgb");
+            assertEquals(GL11.GL_SRC_ALPHA, GLStateManager.getBlendState().getSrcRgb(), "cache blend src rgb");
+            assertEquals(GL11.GL_ONE_MINUS_SRC_ALPHA, GLStateManager.getBlendState().getDstRgb(), "cache blend dst rgb");
+            verifyIsEnabled(GL11.GL_LIGHTING, false, "Lighting enable - restored by BATCH pop");
+            verifyIsEnabled(GL11.GL_STENCIL_TEST, true, "Stencil test - not a BATCH member, must stay toggled");
+        } finally {
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.disableLighting();
+            GLStateManager.glDisable(GL11.GL_STENCIL_TEST);
+        }
+    }
+
+    @Test
+    void fontRestoresDepthAxisAndShadeModelButNotCull() {
+        try {
+            GLStateManager.enableDepthTest();
+            GLStateManager.glDepthFunc(GL11.GL_LEQUAL);
+            GLStateManager.glShadeModel(GL11.GL_SMOOTH);
+            GLStateManager.enableCull();
+            GLStateManager.glCullFace(GL11.GL_BACK);
+
+            final int d = GLStateManager.pushState(StateSet.FONT);
+            GLStateManager.disableDepthTest();
+            GLStateManager.glDepthFunc(GL11.GL_ALWAYS);
+            GLStateManager.glShadeModel(GL11.GL_FLAT);
+            GLStateManager.glCullFace(GL11.GL_FRONT);
+            GLStateManager.popStateTo(d);
+
+            verifyIsEnabled(GL11.GL_DEPTH_TEST, true, "Depth test enable - restored by FONT pop");
+            assertEquals(GL11.GL_LEQUAL, GLStateManager.getDepthState().getFunc(), "cache depth func");
+            assertEquals(GL11.GL_LEQUAL, GL11.glGetInteger(GL11.GL_DEPTH_FUNC), "driver depth func");
+            assertEquals(GL11.GL_SMOOTH, GLStateManager.getShadeModelState().getValue(), "cache shade model");
+            assertEquals(GL11.GL_FRONT, GLStateManager.getPolygonState().getCullFaceMode(), "cache cull face mode - not a FONT member, must stay toggled");
+            assertEquals(GL11.GL_FRONT, GL11.glGetInteger(GL11.GL_CULL_FACE_MODE), "driver cull face mode - not a FONT member, must stay toggled");
+        } finally {
+            GLStateManager.disableDepthTest();
+            GLStateManager.glDepthFunc(GL11.GL_LESS);
+            GLStateManager.glShadeModel(GL11.GL_SMOOTH);
+            GLStateManager.disableCull();
+            GLStateManager.glCullFace(GL11.GL_BACK);
+        }
+    }
+
+    @Test
+    void fontPipelineRestoresBlendAndDepthFuncButNotProgram() {
+        final int p0 = linkTrivialProgram();
+        final int p1 = linkTrivialProgram();
+        try {
+            GLStateManager.glUseProgram(p0);
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.glDepthFunc(GL11.GL_LEQUAL);
+
+            final int d = GLStateManager.pushState(StateSet.FONT_PIPELINE);
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_DST_COLOR, GL11.GL_ZERO, GL11.GL_DST_COLOR, GL11.GL_ZERO);
+            GLStateManager.glDepthFunc(GL11.GL_ALWAYS);
+            GLStateManager.glUseProgram(p1);
+            GLStateManager.popStateTo(d);
+
+            assertEquals(GL11.GL_SRC_ALPHA, GLStateManager.getBlendState().getSrcRgb(), "cache blend src rgb - restored by FONT_PIPELINE pop");
+            assertEquals(GL11.GL_SRC_ALPHA, GL11.glGetInteger(GL14.GL_BLEND_SRC_RGB), "driver blend src rgb - restored by FONT_PIPELINE pop");
+            assertEquals(GL11.GL_LEQUAL, GLStateManager.getDepthState().getFunc(), "cache depth func - restored by FONT_PIPELINE pop");
+            assertEquals(GL11.GL_LEQUAL, GL11.glGetInteger(GL11.GL_DEPTH_FUNC), "driver depth func - restored by FONT_PIPELINE pop");
+            assertEquals(p1, GLStateManager.getActiveProgram(), "program - not a FONT_PIPELINE member, must stay toggled");
+
+            GLStateManager.glUseProgram(p0);
+        } finally {
+            GLStateManager.glUseProgram(0);
+            GLStateManager.glDeleteProgram(p0);
+            GLStateManager.glDeleteProgram(p1);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.glDepthFunc(GL11.GL_LESS);
+        }
+    }
+
+    @Test
+    void handRestoresBlendAxisAndUnit1TexturingButNotColorMask() {
+        try {
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.glColorMask(true, true, true, true);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.enableTexture();
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+
+            final int d = GLStateManager.pushState(StateSet.HAND);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_DST_COLOR, GL11.GL_ZERO, GL11.GL_DST_COLOR, GL11.GL_ZERO);
+            GLStateManager.glColorMask(false, false, false, false);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.disableTexture();
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            GLStateManager.popStateTo(d);
+
+            verifyIsEnabled(GL11.GL_BLEND, true, "Blend enable - restored by HAND pop");
+            assertEquals(GL11.GL_SRC_ALPHA, GLStateManager.getBlendState().getSrcRgb(), "cache blend src rgb");
+            assertEquals(GL11.GL_SRC_ALPHA, GL11.glGetInteger(GL14.GL_BLEND_SRC_RGB), "driver blend src rgb");
+            assertTrue(GLStateManager.getTextures().getTextureUnitStates(1).isEnabled(), "unit 1 texturing - restored by HAND pop");
+
+            final boolean[] driverMask = driverColorWriteMask();
+            assertFalse(driverMask[0] || driverMask[1] || driverMask[2] || driverMask[3], "driver color mask - not a HAND member, must stay toggled");
+            assertFalse(GLStateManager.getColorMask().red || GLStateManager.getColorMask().green
+                || GLStateManager.getColorMask().blue || GLStateManager.getColorMask().alpha, "cache color mask - not a HAND member, must stay toggled");
+        } finally {
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.glColorMask(true, true, true, true);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.disableTexture();
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+        }
+    }
+
+    @Test
+    void masksRestoresDepthMaskAndColorMaskButNotDepthTestEnable() {
+        try {
+            GLStateManager.glDepthMask(true);
+            GLStateManager.glDepthFunc(GL11.GL_LEQUAL);
+            GLStateManager.glColorMask(true, false, true, false);
+            GLStateManager.disableDepthTest();
+
+            final int d = GLStateManager.pushState(StateSet.MASKS);
+            GLStateManager.glDepthMask(false);
+            GLStateManager.glDepthFunc(GL11.GL_ALWAYS);
+            GLStateManager.glColorMask(false, true, false, true);
+            GLStateManager.enableDepthTest();
+            GLStateManager.popStateTo(d);
+
+            assertTrue(GL11.glGetBoolean(GL11.GL_DEPTH_WRITEMASK), "driver depth write mask - restored by MASKS pop");
+            assertTrue(GLStateManager.getDepthState().isEnabled(), "cache depth write mask - restored by MASKS pop");
+            assertEquals(GL11.GL_LEQUAL, GLStateManager.getDepthState().getFunc(), "cache depth func");
+            assertEquals(GL11.GL_LEQUAL, GL11.glGetInteger(GL11.GL_DEPTH_FUNC), "driver depth func");
+
+            final boolean[] driverMask = driverColorWriteMask();
+            assertTrue(driverMask[0] && !driverMask[1] && driverMask[2] && !driverMask[3], "driver color mask - restored by MASKS pop");
+            assertTrue(GLStateManager.getColorMask().red && !GLStateManager.getColorMask().green
+                && GLStateManager.getColorMask().blue && !GLStateManager.getColorMask().alpha, "cache color mask - restored by MASKS pop");
+
+            verifyIsEnabled(GL11.GL_DEPTH_TEST, true, "Depth test enable - not a MASKS member, must stay toggled");
+        } finally {
+            GLStateManager.glDepthMask(true);
+            GLStateManager.glDepthFunc(GL11.GL_LESS);
+            GLStateManager.glColorMask(true, true, true, true);
+            GLStateManager.disableDepthTest();
+        }
+    }
+
+    @Test
+    void cullRestoresPolygonAxisAndCullEnableButNotBlendFunc() {
+        try {
+            GLStateManager.enableCull();
+            GLStateManager.glCullFace(GL11.GL_BACK);
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+
+            final int d = GLStateManager.pushState(StateSet.CULL);
+            GLStateManager.disableCull();
+            GLStateManager.glCullFace(GL11.GL_FRONT);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_DST_COLOR, GL11.GL_ZERO, GL11.GL_DST_COLOR, GL11.GL_ZERO);
+            GLStateManager.popStateTo(d);
+
+            verifyIsEnabled(GL11.GL_CULL_FACE, true, "Cull enable - restored by CULL pop");
+            assertEquals(GL11.GL_BACK, GLStateManager.getPolygonState().getCullFaceMode(), "cache cull face mode");
+            assertEquals(GL11.GL_BACK, GL11.glGetInteger(GL11.GL_CULL_FACE_MODE), "driver cull face mode");
+
+            verifyIsEnabled(GL11.GL_BLEND, false, "Blend enable - not a CULL member, must stay toggled");
+            assertEquals(GL11.GL_DST_COLOR, GLStateManager.getBlendState().getSrcRgb(), "cache blend src rgb - not a CULL member, must stay toggled");
+            assertEquals(GL11.GL_DST_COLOR, GL11.glGetInteger(GL14.GL_BLEND_SRC_RGB), "driver blend src rgb - not a CULL member, must stay toggled");
+        } finally {
+            GLStateManager.disableCull();
+            GLStateManager.glCullFace(GL11.GL_BACK);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+        }
+    }
+
+    @Test
+    void blendRestoresBlendAxisButNotCull() {
+        try {
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.enableCull();
+            GLStateManager.glCullFace(GL11.GL_BACK);
+
+            final int d = GLStateManager.pushState(StateSet.BLEND);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_DST_COLOR, GL11.GL_ZERO, GL11.GL_DST_COLOR, GL11.GL_ZERO);
+            GLStateManager.disableCull();
+            GLStateManager.glCullFace(GL11.GL_FRONT);
+            GLStateManager.popStateTo(d);
+
+            verifyIsEnabled(GL11.GL_BLEND, true, "Blend enable - restored by BLEND pop");
+            assertEquals(GL11.GL_SRC_ALPHA, GLStateManager.getBlendState().getSrcRgb(), "cache blend src rgb");
+            assertEquals(GL11.GL_SRC_ALPHA, GL11.glGetInteger(GL14.GL_BLEND_SRC_RGB), "driver blend src rgb");
+
+            verifyIsEnabled(GL11.GL_CULL_FACE, false, "Cull enable - not a BLEND member, must stay toggled");
+            assertEquals(GL11.GL_FRONT, GLStateManager.getPolygonState().getCullFaceMode(), "cache cull face mode - not a BLEND member, must stay toggled");
+            assertEquals(GL11.GL_FRONT, GL11.glGetInteger(GL11.GL_CULL_FACE_MODE), "driver cull face mode - not a BLEND member, must stay toggled");
+        } finally {
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.disableCull();
+            GLStateManager.glCullFace(GL11.GL_BACK);
+        }
+    }
+
+    @Test
+    void alphaRestoresAlphaAxisButNotBlend() {
+        try {
+            GLStateManager.enableAlphaTest();
+            GLStateManager.glAlphaFunc(GL11.GL_GREATER, 0.5f);
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+
+            final int d = GLStateManager.pushState(StateSet.ALPHA);
+            GLStateManager.disableAlphaTest();
+            GLStateManager.glAlphaFunc(GL11.GL_LESS, 0.1f);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_DST_COLOR, GL11.GL_ZERO, GL11.GL_DST_COLOR, GL11.GL_ZERO);
+            GLStateManager.popStateTo(d);
+
+            verifyIsEnabled(GL11.GL_ALPHA_TEST, true, "Alpha test enable - restored by ALPHA pop");
+            assertEquals(GL11.GL_GREATER, GLStateManager.getAlphaState().getFunction(), "cache alpha func");
+            assertEquals(0.5f, GLStateManager.getAlphaState().getReference(), 0.0001f, "cache alpha ref");
+
+            verifyIsEnabled(GL11.GL_BLEND, false, "Blend enable - not an ALPHA member, must stay toggled");
+            assertEquals(GL11.GL_DST_COLOR, GLStateManager.getBlendState().getSrcRgb(), "cache blend src rgb - not an ALPHA member, must stay toggled");
+            assertEquals(GL11.GL_DST_COLOR, GL11.glGetInteger(GL14.GL_BLEND_SRC_RGB), "driver blend src rgb - not an ALPHA member, must stay toggled");
+        } finally {
+            GLStateManager.disableAlphaTest();
+            GLStateManager.glAlphaFunc(GL11.GL_ALWAYS, 0.0f);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+        }
+    }
+
+    @Test
+    void cutoutRestoresAlphaAxisAndUnit1TexturingButNotBlend() {
+        try {
+            GLStateManager.enableAlphaTest();
+            GLStateManager.glAlphaFunc(GL11.GL_GREATER, 0.5f);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.enableTexture();
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+
+            final int d = GLStateManager.pushState(StateSet.CUTOUT);
+            GLStateManager.disableAlphaTest();
+            GLStateManager.glAlphaFunc(GL11.GL_LESS, 0.1f);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.disableTexture();
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_DST_COLOR, GL11.GL_ZERO, GL11.GL_DST_COLOR, GL11.GL_ZERO);
+
+            final int fragBefore = GLStateManager.ctx().fragmentGeneration;
+            GLStateManager.popStateTo(d);
+
+            assertEquals(fragBefore + 1, GLStateManager.ctx().fragmentGeneration, "CUTOUT pop must bump fragment generation once when the value changed inside the bracket");
+
+            verifyIsEnabled(GL11.GL_ALPHA_TEST, true, "Alpha test enable - restored by CUTOUT pop");
+            assertEquals(GL11.GL_GREATER, GLStateManager.getAlphaState().getFunction(), "cache alpha func");
+            assertEquals(0.5f, GLStateManager.getAlphaState().getReference(), 0.0001f, "cache alpha ref");
+            assertTrue(GLStateManager.getTextures().getTextureUnitStates(1).isEnabled(), "unit 1 texturing - restored by CUTOUT pop");
+
+            verifyIsEnabled(GL11.GL_BLEND, false, "Blend enable - not a CUTOUT member, must stay toggled");
+            assertEquals(GL11.GL_DST_COLOR, GLStateManager.getBlendState().getSrcRgb(), "cache blend src rgb - not a CUTOUT member, must stay toggled");
+            assertEquals(GL11.GL_DST_COLOR, GL11.glGetInteger(GL14.GL_BLEND_SRC_RGB), "driver blend src rgb - not a CUTOUT member, must stay toggled");
+        } finally {
+            GLStateManager.disableAlphaTest();
+            GLStateManager.glAlphaFunc(GL11.GL_ALWAYS, 0.0f);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.disableTexture();
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+        }
+    }
+
+    @Test
+    void cullFaceModeRestoredThroughCullBracket() {
+        try {
+            GLStateManager.glCullFace(GL11.GL_BACK);
+            final int d = GLStateManager.pushState(StateSet.CULL);
+            GLStateManager.glCullFace(GL11.GL_FRONT);
+            GLStateManager.popStateTo(d);
+
+            assertEquals(GL11.GL_BACK, GLStateManager.getPolygonState().getCullFaceMode(), "cache cull face mode");
+            assertEquals(GL11.GL_BACK, GL11.glGetInteger(GL11.GL_CULL_FACE_MODE), "driver cull face mode");
+        } finally {
+            GLStateManager.glCullFace(GL11.GL_BACK);
+        }
+    }
+
+    @Test
+    void cullFaceModeRestoredThroughBatchBracketRegression2117() {
+        try {
+            GLStateManager.glCullFace(GL11.GL_BACK);
+            final int d = GLStateManager.pushState(StateSet.BATCH);
+            GLStateManager.glCullFace(GL11.GL_FRONT);
+            GLStateManager.popStateTo(d);
+
+            assertEquals(GL11.GL_BACK, GLStateManager.getPolygonState().getCullFaceMode(), "cache cull face mode");
+            assertEquals(GL11.GL_BACK, GL11.glGetInteger(GL11.GL_CULL_FACE_MODE), "driver cull face mode");
+        } finally {
+            GLStateManager.glCullFace(GL11.GL_BACK);
+        }
+    }
+
+    @Test
+    void batchRestoresUnit0And1BindingsAndActiveUnitButNotUnit2() {
+        if (GLStateManager.MAX_TEXTURE_UNITS < 3) return;
+        final int tex0Base = GLStateManager.glGenTextures();
+        final int tex1Base = GLStateManager.glGenTextures();
+        final int tex2Base = GLStateManager.glGenTextures();
+        final int tex0Dirty = GLStateManager.glGenTextures();
+        final int tex1Dirty = GLStateManager.glGenTextures();
+        final int tex2Dirty = GLStateManager.glGenTextures();
+        try {
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, tex0Base);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, tex1Base);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0 + 2);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, tex2Base);
+
+            final int d = GLStateManager.pushState(StateSet.BATCH);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, tex0Dirty);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, tex1Dirty);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0 + 2);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, tex2Dirty);
+            GLStateManager.popStateTo(d);
+
+            assertEquals(2, GLStateManager.getActiveTextureUnit(), "cache active unit - restored by BATCH pop");
+            assertEquals(GL13.GL_TEXTURE0 + 2, GL11.glGetInteger(GL13.GL_ACTIVE_TEXTURE), "driver active unit - restored by BATCH pop");
+
+            assertEquals(tex0Base, GLStateManager.getTextures().getTextureUnitBindings(0).getBinding(), "cache unit 0 binding - restored by BATCH pop");
+            assertEquals(tex0Base, driverTextureBinding(0), "driver unit 0 binding - restored by BATCH pop");
+            assertEquals(tex1Base, GLStateManager.getTextures().getTextureUnitBindings(1).getBinding(), "cache unit 1 binding - restored by BATCH pop");
+            assertEquals(tex1Base, driverTextureBinding(1), "driver unit 1 binding - restored by BATCH pop");
+
+            assertEquals(tex2Dirty, GLStateManager.getTextures().getTextureUnitBindings(2).getBinding(), "cache unit 2 binding - not a BATCH member, must stay toggled");
+            assertEquals(tex2Dirty, driverTextureBinding(2), "driver unit 2 binding - not a BATCH member, must stay toggled");
+        } finally {
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, 0);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, 0);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0 + 2);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, 0);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            GLStateManager.glDeleteTextures(tex0Base);
+            GLStateManager.glDeleteTextures(tex1Base);
+            GLStateManager.glDeleteTextures(tex2Base);
+            GLStateManager.glDeleteTextures(tex0Dirty);
+            GLStateManager.glDeleteTextures(tex1Dirty);
+            GLStateManager.glDeleteTextures(tex2Dirty);
+        }
+    }
+
+    @Test
+    void popStateToRepairsUnbalancedInnerPush() {
+        try {
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+            final int d = GLStateManager.pushState(StateSet.BLEND);
+            GLStateManager.pushState(StateSet.CULL);
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.popStateTo(d);
+            assertEquals(d, GLStateManager.getAttribDepth());
+            assertEquals(GL11.GL_ONE, GLStateManager.getBlendState().getSrcRgb(), "popStateTo repairs the unbalanced non-member push and carries the change through to the BLEND member pop, restoring the pre-bracket baseline");
+        } finally {
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+        }
+    }
+
+    @Test
+    void popStateToToleratesUnbalancedInnerPop() {
+        final int d = GLStateManager.pushState(StateSet.BLEND);
+        GLStateManager.popState();
+        assertEquals(d, GLStateManager.getAttribDepth());
+        GLStateManager.popStateTo(d);
+        assertEquals(d, GLStateManager.getAttribDepth());
+    }
+
+    @Test
+    void exceptionMidBracketLeavesDepthAndStateCorrectViaFinally() {
+        try {
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+            final int depthBefore = GLStateManager.getAttribDepth();
+
+            final RuntimeException thrown = assertThrows(RuntimeException.class, () -> {
+                final int d = GLStateManager.pushState(StateSet.BLEND);
+                try {
+                    GLStateManager.disableBlend();
+                    GLStateManager.tryBlendFuncSeparate(GL11.GL_DST_COLOR, GL11.GL_ZERO, GL11.GL_DST_COLOR, GL11.GL_ZERO);
+                    throw new RuntimeException("boom");
+                } finally {
+                    GLStateManager.popStateTo(d);
+                }
+            });
+
+            assertEquals("boom", thrown.getMessage());
+            assertEquals(depthBefore, GLStateManager.getAttribDepth());
+            verifyIsEnabled(GL11.GL_BLEND, true, "Blend enable - restored despite exception");
+            assertEquals(GL11.GL_SRC_ALPHA, GLStateManager.getBlendState().getSrcRgb(), "cache blend src rgb - restored despite exception");
+        } finally {
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+        }
+    }
+
+    @Test
+    void allAttribBitsNestedInsideInternalBracketRestoresBothLevels() {
+        try {
+            GLStateManager.enableCull();
+            GLStateManager.glCullFace(GL11.GL_BACK);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+
+            final int d = GLStateManager.pushState(StateSet.BLEND);
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+
+            GLStateManager.glPushAttrib(GL11.GL_ALL_ATTRIB_BITS);
+            GLStateManager.glCullFace(GL11.GL_FRONT);
+            GLStateManager.glPopAttrib();
+
+            verifyIsEnabled(GL11.GL_CULL_FACE, true, "Cull enable - restored by inner GL_ALL_ATTRIB_BITS pop");
+            assertEquals(GL11.GL_BACK, GLStateManager.getPolygonState().getCullFaceMode(), "cache cull face mode - restored by inner GL_ALL_ATTRIB_BITS pop");
+            assertEquals(GL11.GL_BACK, GL11.glGetInteger(GL11.GL_CULL_FACE_MODE), "driver cull face mode - restored by inner GL_ALL_ATTRIB_BITS pop");
+
+            GLStateManager.popStateTo(d);
+
+            verifyIsEnabled(GL11.GL_BLEND, false, "Blend enable - restored by outer BLEND pop");
+            assertEquals(GL11.GL_ONE, GLStateManager.getBlendState().getSrcRgb(), "cache blend src rgb - restored by outer BLEND pop");
+        } finally {
+            GLStateManager.disableCull();
+            GLStateManager.glCullFace(GL11.GL_BACK);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+        }
+    }
+
+    @Test
+    void internalBracketNestedInsideAllAttribBitsRestoresBothLevels() {
+        try {
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.enableCull();
+            GLStateManager.glCullFace(GL11.GL_BACK);
+
+            GLStateManager.glPushAttrib(GL11.GL_ALL_ATTRIB_BITS);
+            try {
+                GLStateManager.glCullFace(GL11.GL_FRONT);
+
+                final int d = GLStateManager.pushState(StateSet.BLEND);
+                GLStateManager.enableBlend();
+                GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+                GLStateManager.popStateTo(d);
+
+                verifyIsEnabled(GL11.GL_BLEND, false, "Blend enable - restored by inner BLEND pop");
+                assertEquals(GL11.GL_ONE, GLStateManager.getBlendState().getSrcRgb(), "cache blend src rgb - restored by inner BLEND pop");
+                assertEquals(GL11.GL_FRONT, GLStateManager.getPolygonState().getCullFaceMode(), "cache cull face mode - change survives, not a BLEND member");
+                assertEquals(GL11.GL_FRONT, GL11.glGetInteger(GL11.GL_CULL_FACE_MODE), "driver cull face mode - change survives, not a BLEND member");
+            } finally {
+                GLStateManager.glPopAttrib();
+            }
+
+            assertEquals(GL11.GL_BACK, GLStateManager.getPolygonState().getCullFaceMode(), "cache cull face mode - restored by outer GL_ALL_ATTRIB_BITS pop");
+            assertEquals(GL11.GL_BACK, GL11.glGetInteger(GL11.GL_CULL_FACE_MODE), "driver cull face mode - restored by outer GL_ALL_ATTRIB_BITS pop");
+        } finally {
+            GLStateManager.disableCull();
+            GLStateManager.glCullFace(GL11.GL_BACK);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+        }
+    }
+
+    @Test
+    void rProgramFontRestoresRealProgramToDriverAndCache() {
+        final int p0 = linkTrivialProgram();
+        final int p1 = linkTrivialProgram();
+        try {
+            GLStateManager.glUseProgram(p0);
+
+            final int d = GLStateManager.pushState(StateSet.FONT);
+            GLStateManager.glUseProgram(p1);
+            GLStateManager.popStateTo(d);
+
+            assertEquals(p0, GLStateManager.getActiveProgram(), "cache active program restored");
+            assertEquals(p0, GL11.glGetInteger(GL20.GL_CURRENT_PROGRAM), "driver current program restored");
+            assertFalse(ShaderManager.getInstance().isActive(), "FFP must stay inactive when a real program was bound before the bracket");
+        } finally {
+            GLStateManager.glUseProgram(0);
+            GLStateManager.glDeleteProgram(p0);
+            GLStateManager.glDeleteProgram(p1);
+        }
+    }
+
+    @Test
+    void rProgramFontReactivatesFfpAfterBracket() {
+        final int p1 = linkTrivialProgram();
+        try {
+            GLStateManager.glUseProgram(0);
+            assertTrue(ShaderManager.getInstance().isActive(), "FFP must be active before the bracket");
+
+            final int d = GLStateManager.pushState(StateSet.FONT);
+            GLStateManager.glUseProgram(p1);
+            assertFalse(ShaderManager.getInstance().isActive(), "FFP must deactivate once a real program binds");
+            GLStateManager.popStateTo(d);
+
+            assertEquals(0, GLStateManager.getActiveProgram(), "cache active program restored to the FFP sentinel");
+            assertTrue(ShaderManager.getInstance().isActive(), "FFP must be active again after the pop");
+        } finally {
+            GLStateManager.glUseProgram(0);
+            GLStateManager.glDeleteProgram(p1);
+        }
+    }
+
+    @Test
+    void blendPopDoesNotBumpFragmentOrLightingGeneration() {
+        try {
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+
+            final int d = GLStateManager.pushState(StateSet.BLEND);
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_DST_COLOR, GL11.GL_ZERO, GL11.GL_DST_COLOR, GL11.GL_ZERO);
+
+            final int fragBefore = GLStateManager.ctx().fragmentGeneration;
+            final int lightBefore = GLStateManager.ctx().lightingGeneration;
+            GLStateManager.popStateTo(d);
+
+            assertEquals(fragBefore, GLStateManager.ctx().fragmentGeneration, "BLEND pop must not bump fragment generation");
+            assertEquals(lightBefore, GLStateManager.ctx().lightingGeneration, "BLEND pop must not bump lighting generation");
+        } finally {
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+        }
+    }
+
+    @Test
+    void alphaPopBumpsFragmentGenerationWhenChanged() {
+        try {
+            GLStateManager.enableAlphaTest();
+            GLStateManager.glAlphaFunc(GL11.GL_GREATER, 0.5f);
+
+            final int d = GLStateManager.pushState(StateSet.ALPHA);
+            GLStateManager.glAlphaFunc(GL11.GL_LESS, 0.1f);
+
+            final int fragBefore = GLStateManager.ctx().fragmentGeneration;
+            GLStateManager.popStateTo(d);
+
+            assertEquals(fragBefore + 1, GLStateManager.ctx().fragmentGeneration, "ALPHA pop must bump fragment generation once when the value changed inside the bracket");
+        } finally {
+            GLStateManager.disableAlphaTest();
+            GLStateManager.glAlphaFunc(GL11.GL_ALWAYS, 0.0f);
+        }
+    }
+
+    @Test
+    void textureBitBracketRestoresUnit1BindingAndActiveUnit() {
+        final int texBase = GLStateManager.glGenTextures();
+        final int texDirty = GLStateManager.glGenTextures();
+        try {
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texBase);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            final int d = GLStateManager.pushState(StateSet.forMask(GL11.GL_TEXTURE_BIT));
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texDirty);
+            GLStateManager.popStateTo(d);
+            assertEquals(0, GLStateManager.getActiveTextureUnit(), "cache active unit restored by GL_TEXTURE_BIT pop");
+            assertEquals(GL13.GL_TEXTURE0, GL11.glGetInteger(GL13.GL_ACTIVE_TEXTURE), "driver active unit restored by GL_TEXTURE_BIT pop");
+            assertEquals(texBase, GLStateManager.getTextures().getTextureUnitBindings(1).getBinding(), "cache unit 1 binding restored by GL_TEXTURE_BIT pop");
+            assertEquals(texBase, driverTextureBinding(1), "driver unit 1 binding restored by GL_TEXTURE_BIT pop");
+        } finally {
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, 0);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            GLStateManager.glDeleteTextures(texBase);
+            GLStateManager.glDeleteTextures(texDirty);
+        }
+    }
+
+    @Test
+    void textureBitBracketRestoresTexEnvModeAndColor() {
+        GLStateManager.glTexEnvi(GL11.GL_TEXTURE_ENV, GL11.GL_TEXTURE_ENV_MODE, GL11.GL_MODULATE);
+        final FloatBuffer zero = BufferUtils.createFloatBuffer(4);
+        zero.put(0.0f).put(0.0f).put(0.0f).put(0.0f).flip();
+        GLStateManager.glTexEnv(GL11.GL_TEXTURE_ENV, GL11.GL_TEXTURE_ENV_COLOR, zero);
+        try {
+            final int d = GLStateManager.pushState(StateSet.forMask(GL11.GL_TEXTURE_BIT));
+            GLStateManager.glTexEnvi(GL11.GL_TEXTURE_ENV, GL11.GL_TEXTURE_ENV_MODE, GL11.GL_DECAL);
+            final FloatBuffer dirty = BufferUtils.createFloatBuffer(4);
+            dirty.put(0.1f).put(0.2f).put(0.3f).put(0.4f).flip();
+            GLStateManager.glTexEnv(GL11.GL_TEXTURE_ENV, GL11.GL_TEXTURE_ENV_COLOR, dirty);
+            GLStateManager.popStateTo(d);
+            assertEquals(GL11.GL_MODULATE, GLStateManager.getTextures().getTexEnvState(0).mode, "cache tex env mode restored by GL_TEXTURE_BIT pop");
+            assertEquals(0.0f, GLStateManager.getTextures().getTexEnvState(0).envColorR, 0.0001f, "cache tex env color restored by GL_TEXTURE_BIT pop");
+        } finally {
+            GLStateManager.glTexEnvi(GL11.GL_TEXTURE_ENV, GL11.GL_TEXTURE_ENV_MODE, GL11.GL_MODULATE);
+        }
+    }
+
+    @Test
+    void lightingBitBracketRestoresBakedFrontMaterialAfterColorMaterialToggle() {
+        try {
+            GLStateManager.glColor4f(0.9f, 0.9f, 0.9f, 0.9f);
+            GLStateManager.enableColorMaterial();
+            GLStateManager.disableColorMaterial();
+            final int d = GLStateManager.pushState(StateSet.forMask(GL11.GL_LIGHTING_BIT));
+            GLStateManager.glColor4f(0.1f, 0.2f, 0.3f, 0.4f);
+            GLStateManager.enableColorMaterial();
+            GLStateManager.popStateTo(d);
+            assertEquals(0.9f, GLStateManager.getFrontMaterial().ambient.x, 0.0001f, "cache front material ambient restored by GL_LIGHTING_BIT pop");
+            assertEquals(0.9f, GLStateManager.getFrontMaterial().diffuse.x, 0.0001f, "cache front material diffuse restored by GL_LIGHTING_BIT pop");
+        } finally {
+            GLStateManager.disableColorMaterial();
+            GLStateManager.glColorMaterial(GL11.GL_FRONT_AND_BACK, GL11.GL_AMBIENT_AND_DIFFUSE);
+        }
+    }
+}

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/GLSM_VAO_UnitTest.java

@@ -17,7 +17,7 @@ public class GLSM_VAO_UnitTest {
 
     @Test
     void testDefaultStates() {
-        verifyState(GL30.GL_VERTEX_ARRAY_BINDING, GLStateManager.getDefaultVAO(), "GL_VERTEX_ARRAY_BINDING Initial State");
+        verifyState(GL30.GL_VERTEX_ARRAY_BINDING, GLStateManager.ctx().defaultVAO, "GL_VERTEX_ARRAY_BINDING Initial State");
         verifyState(GL13.GL_CLIENT_ACTIVE_TEXTURE, GL13.GL_TEXTURE0, "GL_CLIENT_ACTIVE_TEXTURE Initial State");
         testClientStates();
     }
@@ -84,7 +84,7 @@ public class GLSM_VAO_UnitTest {
 
         // Check if everything got reset to default
         glBindVertexArray(0);
-        verifyState(GL30.GL_VERTEX_ARRAY_BINDING, GLStateManager.getDefaultVAO(), "GL_VERTEX_ARRAY_BINDING - Unbound");
+        verifyState(GL30.GL_VERTEX_ARRAY_BINDING, GLStateManager.ctx().defaultVAO, "GL_VERTEX_ARRAY_BINDING - Unbound");
         verifyState(GL15.GL_ARRAY_BUFFER_BINDING, 0, "GL_ARRAY_BUFFER_BINDING - Unbound");
 
         verifyState(GL11.GL_VERTEX_ARRAY, defaultVertexEnabled, "GL_VERTEX_ARRAY - Reset");
@@ -192,9 +192,10 @@ public class GLSM_VAO_UnitTest {
     }
 
     private static void glBindVertexArray(int array) {
-        if (array == 0) array = GLStateManager.getDefaultVAO();
-        GLStateManager.ctx().boundVAO = array;
-        VAOManager.onBindVertexArrayPre(array);
+        final GLContextState glCtx = GLStateManager.ctx();
+        if (array == 0) array = glCtx.defaultVAO;
+        glCtx.boundVAO = array;
+        glCtx.vaos.onBindVertexArrayPre(array);
         UniversalVAO.bindVertexArray(array);
     }
 }

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/GLSM_ValueStackCow_GLTest.java

@@ -0,0 +1,152 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.Test;
+import org.lwjgl.BufferUtils;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL12;
+import org.lwjgl.opengl.GL13;
+import org.lwjgl.opengl.GL14;
+
+import java.nio.FloatBuffer;
+
+import com.gtnewhorizons.angelica.glsm.dsa.DSAARB;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
+
+@GLCoreTest
+public class GLSM_ValueStackCow_GLTest {
+
+    private static int fixtureTexA = -1;
+    private static int fixtureTexB = -1;
+
+    private static FloatBuffer buf4(float a, float b, float c, float d) {
+        final FloatBuffer buf = BufferUtils.createFloatBuffer(4);
+        buf.put(a).put(b).put(c).put(d).flip();
+        return buf;
+    }
+
+    private static void ensureFixtureTextures() {
+        if (fixtureTexA == -1) {
+            fixtureTexA = GLStateManager.glGenTextures();
+            fixtureTexB = GLStateManager.glGenTextures();
+        }
+    }
+
+    @AfterAll
+    static void deleteFixtureTextures() {
+        if (fixtureTexA > 0) GLStateManager.glDeleteTextures(fixtureTexA);
+        if (fixtureTexB > 0) GLStateManager.glDeleteTextures(fixtureTexB);
+        fixtureTexA = fixtureTexB = -1;
+    }
+
+    private static final String[] NAMES = {
+        "glAlphaFunc", "glBlendFunc", "tryBlendFuncSeparate", "glBlendEquation", "glBlendEquationSeparate",
+        "glBlendColor", "glColorMask", "glClearColor", "glDrawBuffer", "glLogicOp",
+        "glDepthFunc", "glDepthMask", "glClearDepth", "glStencilFunc", "glStencilOp",
+        "glStencilMask", "glClearStencil", "glViewport", "glScissor", "glDepthRange", "glLineWidth",
+        "glLineStipple", "glPointSize", "glPolygonMode", "glCullFace", "glFrontFace",
+        "glPolygonOffset", "fogColor", "glFogf", "glFogi", "glLightf",
+        "glLighti", "glLight", "glLightModelf", "glLightModeli", "glLightModel",
+        "glMaterialf", "glMateriali", "glMaterial", "glShadeModel", "glColorMaterial",
+        "glMatrixMode", "glActiveTexture", "glBindTexture", "glTexEnvi", "glTexEnv",
+        "glSecondaryColor3ub", "enableBlend/disableBlend", "enableAlphaTest/disableAlphaTest",
+        "glEnable(GL_CULL_FACE)", "dsaBindTextureToUnit"
+    };
+
+    private static final Runnable[] MUTATIONS = {
+        () -> GLStateManager.glAlphaFunc(GL11.GL_LESS, 0.1f),
+        () -> GLStateManager.glBlendFunc(GL11.GL_DST_COLOR, GL11.GL_ZERO),
+        () -> GLStateManager.tryBlendFuncSeparate(GL11.GL_DST_COLOR, GL11.GL_ZERO, GL11.GL_DST_COLOR, GL11.GL_ZERO),
+        () -> GLStateManager.glBlendEquation(GL14.GL_FUNC_SUBTRACT),
+        () -> GLStateManager.glBlendEquationSeparate(GL14.GL_FUNC_SUBTRACT, GL14.GL_FUNC_REVERSE_SUBTRACT),
+        () -> GLStateManager.glBlendColor(0.5f, 0.6f, 0.7f, 0.8f),
+        () -> GLStateManager.glColorMask(false, true, false, true),
+        () -> GLStateManager.glClearColor(1.0f, 0.5f, 0.25f, 0.75f),
+        () -> GLStateManager.glDrawBuffer(GL11.GL_NONE),
+        () -> GLStateManager.glLogicOp(GL11.GL_XOR),
+        () -> GLStateManager.glDepthFunc(GL11.GL_ALWAYS),
+        () -> GLStateManager.glDepthMask(false),
+        () -> GLStateManager.glClearDepth(0.25),
+        () -> GLStateManager.glStencilFunc(GL11.GL_NOTEQUAL, 3, 0x0F),
+        () -> GLStateManager.glStencilOp(GL11.GL_REPLACE, GL11.GL_INCR, GL11.GL_DECR),
+        () -> GLStateManager.glStencilMask(0x0F),
+        () -> GLStateManager.glClearStencil(9),
+        () -> GLStateManager.glViewport(1, 2, 3, 4),
+        () -> GLStateManager.glScissor(1, 2, 3, 4),
+        () -> GLStateManager.glDepthRange(0.2, 0.8),
+        () -> GLStateManager.glLineWidth(3.0f),
+        () -> GLStateManager.glLineStipple(3, (short) 0x00FF),
+        () -> GLStateManager.glPointSize(4.0f),
+        () -> GLStateManager.glPolygonMode(GL11.GL_FRONT_AND_BACK, GL11.GL_LINE),
+        () -> GLStateManager.glCullFace(GL11.GL_FRONT),
+        () -> GLStateManager.glFrontFace(GL11.GL_CW),
+        () -> GLStateManager.glPolygonOffset(3.0f, 4.0f),
+        () -> GLStateManager.fogColor(0.5f, 0.6f, 0.7f, 0.8f),
+        () -> GLStateManager.glFogf(GL11.GL_FOG_DENSITY, 0.5f),
+        () -> GLStateManager.glFogi(GL11.GL_FOG_MODE, GL11.GL_LINEAR),
+        () -> GLStateManager.glLightf(GL11.GL_LIGHT0, GL11.GL_SPOT_EXPONENT, 12.0f),
+        () -> GLStateManager.glLighti(GL11.GL_LIGHT0, GL11.GL_SPOT_CUTOFF, 45),
+        () -> GLStateManager.glLight(GL11.GL_LIGHT0, GL11.GL_POSITION, buf4(1.0f, 2.0f, 3.0f, 1.0f)),
+        () -> GLStateManager.glLightModelf(GL11.GL_LIGHT_MODEL_LOCAL_VIEWER, 1.0f),
+        () -> GLStateManager.glLightModeli(GL12.GL_LIGHT_MODEL_COLOR_CONTROL, GL12.GL_SEPARATE_SPECULAR_COLOR),
+        () -> GLStateManager.glLightModel(GL11.GL_LIGHT_MODEL_AMBIENT, buf4(0.5f, 0.6f, 0.7f, 0.8f)),
+        () -> GLStateManager.glMaterialf(GL11.GL_FRONT_AND_BACK, GL11.GL_SHININESS, 32.0f),
+        () -> GLStateManager.glMateriali(GL11.GL_FRONT_AND_BACK, GL11.GL_SHININESS, 32),
+        () -> GLStateManager.glMaterial(GL11.GL_FRONT, GL11.GL_DIFFUSE, buf4(0.1f, 0.2f, 0.3f, 0.4f)),
+        () -> GLStateManager.glShadeModel(GL11.GL_FLAT),
+        () -> GLStateManager.glColorMaterial(GL11.GL_FRONT, GL11.GL_SPECULAR),
+        () -> GLStateManager.glMatrixMode(GL11.GL_PROJECTION),
+        () -> GLStateManager.glActiveTexture(GL13.GL_TEXTURE0 + 2),
+        () -> {
+            ensureFixtureTextures();
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, 0);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, fixtureTexA);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+        },
+        () -> GLStateManager.glTexEnvi(GL11.GL_TEXTURE_ENV, GL11.GL_TEXTURE_ENV_MODE, GL11.GL_DECAL),
+        () -> GLStateManager.glTexEnv(GL11.GL_TEXTURE_ENV, GL11.GL_TEXTURE_ENV_COLOR, buf4(0.1f, 0.2f, 0.3f, 0.4f)),
+        () -> GLStateManager.glSecondaryColor3ub((byte) 255, (byte) 128, (byte) 64),
+        () -> {
+            GLStateManager.disableBlend();
+            GLStateManager.enableBlend();
+        },
+        () -> {
+            GLStateManager.disableAlphaTest();
+            GLStateManager.enableAlphaTest();
+        },
+        () -> {
+            GLStateManager.glDisable(GL11.GL_CULL_FACE);
+            GLStateManager.glEnable(GL11.GL_CULL_FACE);
+        },
+        () -> {
+            assumeTrue(GLStateManager.capabilities.GL_ARB_direct_state_access, "test requires GL_ARB_direct_state_access");
+            ensureFixtureTextures();
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE1);
+            GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, fixtureTexA);
+            GLStateManager.glActiveTexture(GL13.GL_TEXTURE0);
+            new DSAARB().bindTextureToUnit(1, fixtureTexB);
+        }
+    };
+
+    @Test
+    void everyMutationSiteReachesTheSaveHook() {
+        final int entryDepth = GLStateManager.getAttribDepth();
+        try {
+            for (int i = 0; i < MUTATIONS.length; i++) {
+                final int d = GLStateManager.pushState(StateSet.forMask(GL11.GL_ALL_ATTRIB_BITS));
+                try {
+                    final long before = GLStateManager.attribSlotsSaved;
+                    MUTATIONS[i].run();
+                    assertTrue(GLStateManager.attribSlotsSaved - before >= 1, NAMES[i] + ": mutation site did not reach the save hook");
+                } finally {
+                    GLStateManager.popStateTo(d);
+                }
+            }
+        } finally {
+            GLStateManager.popStateTo(entryDepth);
+        }
+    }
+}

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/GLSM_WorkerContextStacks_GLTest.java

@@ -0,0 +1,100 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.testutil.Reflect;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+import org.lwjgl.opengl.GL11;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+@GLCoreTest
+public class GLSM_WorkerContextStacks_GLTest {
+
+    @Test
+    void enableBitBracketRestoresOnWorkerContext() {
+        GLStateManager.enterWorkerContext();
+        try {
+            GLStateManager.glDisable(GL11.GL_CULL_FACE);
+
+            final int d = GLStateManager.pushState(StateSet.forMask(GL11.GL_ENABLE_BIT));
+            GLStateManager.glEnable(GL11.GL_CULL_FACE);
+            GLStateManager.popStateTo(d);
+
+            assertFalse(GLStateManager.glIsEnabled(GL11.GL_CULL_FACE), "cull face restored on the worker context");
+        } finally {
+            GLStateManager.glDisable(GL11.GL_CULL_FACE);
+            GLStateManager.exitWorkerContext();
+        }
+    }
+
+    @Test
+    void colorBufferBitBracketRestoresOnWorkerContext() {
+        GLStateManager.enterWorkerContext();
+        try {
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+
+            final int d = GLStateManager.pushState(StateSet.forMask(GL11.GL_COLOR_BUFFER_BIT));
+            GLStateManager.enableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.popStateTo(d);
+
+            assertFalse(GLStateManager.glIsEnabled(GL11.GL_BLEND), "blend enable restored on the worker context");
+            assertEquals(GL11.GL_ONE, GLStateManager.getBlendState().getSrcRgb(), "blend src rgb restored on the worker context");
+        } finally {
+            GLStateManager.disableBlend();
+            GLStateManager.tryBlendFuncSeparate(GL11.GL_ONE, GL11.GL_ZERO, GL11.GL_ONE, GL11.GL_ZERO);
+            GLStateManager.exitWorkerContext();
+        }
+    }
+
+    @Test
+    void workerResetLeavesPrimaryContextUntouched() {
+        GLStateManager.glDisable(GL11.GL_CULL_FACE);
+        final int primaryDepthBefore = GLStateManager.getAttribDepth();
+
+        GLStateManager.enterWorkerContext();
+        try {
+            GLStateManager.pushState(StateSet.forMask(GL11.GL_ENABLE_BIT));
+            GLStateManager.glEnable(GL11.GL_CULL_FACE);
+
+            GLStateManager.reset();
+
+            assertEquals(0, GLStateManager.getAttribDepth(), "worker attrib depth drained by its own reset");
+        } finally {
+            GLStateManager.exitWorkerContext();
+        }
+
+        assertEquals(primaryDepthBefore, GLStateManager.getAttribDepth(), "primary context depth untouched by the worker reset");
+        assertFalse(GLStateManager.glIsEnabled(GL11.GL_CULL_FACE), "primary context cull face untouched by the worker reset");
+    }
+
+    @Test
+    void stackIdsEqualAcrossContexts() {
+        final GLContextState primary = GLStateManager.ctx();
+        final GLContextState worker = GLStateManager.enterWorkerContext();
+        try {
+            final Object[] primaryStacks = {
+                primary.blendState, primary.depthState, primary.colorMask, primary.blendMode,
+                primary.cullState, primary.textures.getTextureUnitBindings(1), primary.polygonState
+            };
+            final Object[] workerStacks = {
+                worker.blendState, worker.depthState, worker.colorMask, worker.blendMode,
+                worker.cullState, worker.textures.getTextureUnitBindings(1), worker.polygonState
+            };
+
+            final int[] primaryIds = new int[primaryStacks.length];
+            final int[] workerIds = new int[workerStacks.length];
+            for (int i = 0; i < primaryStacks.length; i++) {
+                primaryIds[i] = Reflect.invoke(primaryStacks[i], "stackId", new Class[0]);
+                workerIds[i] = Reflect.invoke(workerStacks[i], "stackId", new Class[0]);
+            }
+
+            assertArrayEquals(primaryIds, workerIds, "stack ids must match between the primary and worker contexts for identically-constructed stacks");
+        } finally {
+            GLStateManager.exitWorkerContext();
+        }
+    }
+}

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/VertexAttribDefaultBridgeTest.java

@@ -28,7 +28,7 @@ class VertexAttribDefaultBridgeTest {
     @Test
     void testGlColor4fSetsVertexAttrib() {
         GLStateManager.glColor4f(0.5f, 0.25f, 0.75f, 0.8f);
-        GLStateManager.flushDeferredVertexAttribs(false, false, false, false);
+        GLStateManager.flushDeferredVertexAttribs(GLStateManager.ctx(), false, false, false, false);
 
         float[] color = getVertexAttrib4f(COLOR_ATTRIB);
         assertEquals(0.5f, color[0], EPSILON, "color.r");
@@ -40,7 +40,7 @@ class VertexAttribDefaultBridgeTest {
     @Test
     void testGlNormal3fSetsVertexAttrib() {
         GLStateManager.glNormal3f(0.0f, 1.0f, 0.0f);
-        GLStateManager.flushDeferredVertexAttribs(false, false, false, false);
+        GLStateManager.flushDeferredVertexAttribs(GLStateManager.ctx(), false, false, false, false);
 
         float[] normal = getVertexAttrib4f(NORMAL_ATTRIB);
         assertEquals(0.0f, normal[0], EPSILON, "normal.x");
@@ -51,7 +51,7 @@ class VertexAttribDefaultBridgeTest {
     @Test
     void testSetLightmapTextureCoordsOnUnit1SetsVertexAttrib() {
         GLStateManager.setLightmapTextureCoords(GL13.GL_TEXTURE1, 240.0f, 128.0f);
-        GLStateManager.flushDeferredVertexAttribs(false, false, false, false);
+        GLStateManager.flushDeferredVertexAttribs(GLStateManager.ctx(), false, false, false, false);
 
         float[] lm = getVertexAttrib4f(SECONDARY_UV_ATTRIB);
         assertEquals(240.0f, lm[0], EPSILON, "lightmap.s");
@@ -64,7 +64,7 @@ class VertexAttribDefaultBridgeTest {
     void testGlTexCoord2fSetsVertexAttrib() {
         // glTexCoord2f outside recording → sets default vertex attrib 2 (PRIMARY_UV)
         GLStateManager.glTexCoord2f(0.5f, 0.75f);
-        GLStateManager.flushDeferredVertexAttribs(false, false, false, false);
+        GLStateManager.flushDeferredVertexAttribs(GLStateManager.ctx(), false, false, false, false);
 
         float[] uv = getVertexAttrib4f(PRIMARY_UV_ATTRIB);
         assertEquals(0.5f, uv[0], EPSILON, "texcoord.s");
@@ -77,7 +77,7 @@ class VertexAttribDefaultBridgeTest {
         // Second call is a cache hit — changeColor not called.
         // Vertex attrib should still hold the correct value from the first call.
         GLStateManager.glColor4f(0.3f, 0.6f, 0.9f, 1.0f);
-        GLStateManager.flushDeferredVertexAttribs(false, false, false, false);
+        GLStateManager.flushDeferredVertexAttribs(GLStateManager.ctx(), false, false, false, false);
 
         float[] color = getVertexAttrib4f(COLOR_ATTRIB);
         assertEquals(0.3f, color[0], EPSILON, "color.r after dedup");
@@ -89,7 +89,7 @@ class VertexAttribDefaultBridgeTest {
     @Test
     void testCompileMode_DoesNotSetVertexAttrib() {
         GLStateManager.glColor4f(0.1f, 0.2f, 0.3f, 1.0f);
-        GLStateManager.flushDeferredVertexAttribs(false, false, false, false);
+        GLStateManager.flushDeferredVertexAttribs(GLStateManager.ctx(), false, false, false, false);
 
         int listId = GLStateManager.glGenLists(1);
         GLStateManager.glNewList(listId, GL11.GL_COMPILE);

glsm/src/test/java/com/gtnewhorizons/angelica/glsm/ffp/FFPCombineShaderTest.java

@@ -245,7 +245,7 @@ class FFPCombineShaderTest {
     @Test
     void testMultiTexCoordRoutesToShaderManager() {
         // Not in immediate mode or display list recording, so should go to ShaderManager.currentTexCoord
-        ShaderManager.setCurrentTexCoord(0.0f, 0.0f, 0.0f, 1.0f); // reset
+        GLStateManager.ctx().ffp.setTexCoord(0.0f, 0.0f, 0.0f, 1.0f); // reset
         GLStateManager.glMultiTexCoord2f(GL13.GL_TEXTURE0, 0.5f, 0.75f);
 
         var texCoord = ShaderManager.getCurrentTexCoord();
@@ -255,7 +255,7 @@ class FFPCombineShaderTest {
 
     @Test
     void testMultiTexCoord2dDelegatesToFloat() {
-        ShaderManager.setCurrentTexCoord(0.0f, 0.0f, 0.0f, 1.0f);
+        GLStateManager.ctx().ffp.setTexCoord(0.0f, 0.0f, 0.0f, 1.0f);
         GLStateManager.glMultiTexCoord2d(GL13.GL_TEXTURE0, 0.5, 0.75);
 
         var texCoord = ShaderManager.getCurrentTexCoord();