Misc. tweaks

- Drastically reduce stutter on origin shift (it's still bad)
 - GPUInstancers mark their buffers as dynamic

src/main/java/com/jozufozu/flywheel/backend/instancing/InstanceManager.java

@@ -327,12 +327,18 @@ public abstract class InstanceManager<T> implements InstancingEngine.OriginShift
 		AbstractInstance renderer = createRaw(obj);
 
 		if (renderer != null) {
+			setup(obj, renderer);
+			instances.put(obj, renderer);
+		}
+
+		return renderer;
+	}
+
+	private void setup(T obj, AbstractInstance renderer) {
 		renderer.init();
 		renderer.updateLight();
 		LightUpdater.get(renderer.level)
 				.addListener(renderer);
-			instances.put(obj, renderer);
-
 		if (renderer instanceof TickableInstance r) {
 			tickableInstances.put(obj, r);
 			r.tick();
@@ -344,14 +350,21 @@ public abstract class InstanceManager<T> implements InstancingEngine.OriginShift
 		}
 	}
 
-		return renderer;
-	}
-
 	@Override
 	public void onOriginShift() {
-		ArrayList<T> instanced = new ArrayList<>(instances.keySet());
-		invalidate();
-		instanced.forEach(this::add);
+		dynamicInstances.clear();
+		tickableInstances.clear();
+		instances.replaceAll((obj, instance) -> {
+			instance.remove();
+
+			AbstractInstance out = createRaw(obj);
+
+			if (out != null) {
+				setup(obj, out);
+			}
+
+			return out;
+		});
 	}
 
 	public void detachLightListeners() {

src/main/java/com/jozufozu/flywheel/backend/instancing/InstancedRenderDispatcher.java

@@ -3,7 +3,6 @@ package com.jozufozu.flywheel.backend.instancing;
 import java.util.List;
 
 import com.jozufozu.flywheel.backend.Backend;
-import com.jozufozu.flywheel.backend.model.MeshPool;
 import com.jozufozu.flywheel.config.FlwCommands;
 import com.jozufozu.flywheel.config.FlwConfig;
 import com.jozufozu.flywheel.core.RenderContext;
@@ -18,10 +17,7 @@ import net.minecraft.client.renderer.RenderType;
 import net.minecraft.world.entity.Entity;
 import net.minecraft.world.level.LevelAccessor;
 import net.minecraft.world.level.block.entity.BlockEntity;
-import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.event.TickEvent;
-import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.common.Mod;
 
 public class InstancedRenderDispatcher {
 

src/main/java/com/jozufozu/flywheel/backend/instancing/ParallelTaskEngine.java

@@ -268,8 +268,8 @@ public class ParallelTaskEngine implements TaskEngine {
 		}
 
 		public void oneDown() {
-			if (running.decrementAndGet() == 0) {
 			if (finalizer != null) {
+				if (running.decrementAndGet() == 0) {
 					ParallelTaskEngine.this.syncTasks.add(finalizer);
 				}
 			}

src/main/java/com/jozufozu/flywheel/backend/instancing/batching/WaitGroup.java

@@ -1,23 +1,33 @@
 package com.jozufozu.flywheel.backend.instancing.batching;
 
+import java.util.concurrent.atomic.AtomicInteger;
+
 // https://stackoverflow.com/questions/29655531
 public class WaitGroup {
 
-	private int jobs = 0;
+	private final AtomicInteger counter = new AtomicInteger(0);
 
 	public synchronized void add(int i) {
-		jobs += i;
+		if (i == 0) {
+			return;
+		}
+
+		if (i == 1) {
+			this.counter.incrementAndGet();
+		} else {
+			this.counter.addAndGet(i);
+		}
 	}
 
 	public synchronized void done() {
-		if (--jobs == 0) {
-			notifyAll();
+		if (this.counter.decrementAndGet() == 0) {
+			this.notifyAll();
 		}
 	}
 
 	public synchronized void await() throws InterruptedException {
-		while (jobs > 0) {
-			wait();
+		while (this.counter.get() > 0) {
+			this.wait();
 		}
 	}
 

src/main/java/com/jozufozu/flywheel/backend/instancing/instancing/GPUInstancer.java

@@ -10,6 +10,7 @@ import com.jozufozu.flywheel.api.struct.StructWriter;
 import com.jozufozu.flywheel.backend.gl.GlVertexArray;
 import com.jozufozu.flywheel.backend.gl.buffer.GlBuffer;
 import com.jozufozu.flywheel.backend.gl.buffer.GlBufferType;
+import com.jozufozu.flywheel.backend.gl.buffer.GlBufferUsage;
 import com.jozufozu.flywheel.backend.gl.buffer.MappedBuffer;
 import com.jozufozu.flywheel.backend.gl.buffer.MappedGlBuffer;
 import com.jozufozu.flywheel.backend.instancing.AbstractInstancer;
@@ -42,7 +43,7 @@ public class GPUInstancer<D extends InstancedPart> extends AbstractInstancer<D>
 	public void init() {
 		if (vbo != null) return;
 
-		vbo = new MappedGlBuffer(GlBufferType.ARRAY_BUFFER);
+		vbo = new MappedGlBuffer(GlBufferType.ARRAY_BUFFER, GlBufferUsage.DYNAMIC_DRAW);
 		vbo.setGrowthMargin(instanceFormat.getStride() * 16);
 	}
 
@@ -53,6 +54,14 @@ public class GPUInstancer<D extends InstancedPart> extends AbstractInstancer<D>
 	private final Set<GlVertexArray> boundTo = new HashSet<>();
 
 	void renderSetup(GlVertexArray vao) {
+		update();
+
+		if (boundTo.add(vao)) {
+			bindInstanceAttributes(vao);
+		}
+	}
+
+	private void update() {
 		if (anyToRemove) {
 			removeDeletedInstances();
 		}
@@ -68,10 +77,6 @@ public class GPUInstancer<D extends InstancedPart> extends AbstractInstancer<D>
 
 		glInstanceCount = data.size();
 
-		if (boundTo.add(vao)) {
-			bindInstanceAttributes(vao);
-		}
-
 		anyToRemove = anyToUpdate = false;
 	}
 

src/main/java/com/jozufozu/flywheel/backend/instancing/instancing/InstancingEngine.java

@@ -33,6 +33,7 @@ import com.jozufozu.flywheel.core.compile.ProgramCompiler;
 import com.jozufozu.flywheel.core.crumbling.CrumblingProgram;
 import com.jozufozu.flywheel.core.model.Mesh;
 import com.jozufozu.flywheel.core.model.ModelSupplier;
+import com.jozufozu.flywheel.core.shader.StateSnapshot;
 import com.jozufozu.flywheel.core.shader.WorldProgram;
 import com.jozufozu.flywheel.core.source.FileResolution;
 import com.jozufozu.flywheel.core.vertex.Formats;
@@ -140,6 +141,7 @@ public class InstancingEngine<P extends WorldProgram> implements Engine {
 		type.setupRenderState();
 		Textures.bindActiveTextures();
 		CoreShaderInfo coreShaderInfo = CoreShaderInfo.get();
+		StateSnapshot state = GameStateRegistry.takeSnapshot();
 
 		for (var entry : Multimaps.asMap(multimap).entrySet()) {
 			var shader = entry.getKey();
@@ -151,7 +153,7 @@ public class InstancingEngine<P extends WorldProgram> implements Engine {
 				continue;
 			}
 
-			setup(shader, coreShaderInfo, camX, camY, camZ, viewProjection, level);
+			setup(shader, coreShaderInfo, camX, camY, camZ, viewProjection, level, state);
 
 			for (var drawCall : drawCalls) {
 				drawCall.render();
@@ -162,7 +164,7 @@ public class InstancingEngine<P extends WorldProgram> implements Engine {
 		type.clearRenderState();
 	}
 
-	protected P setup(ShaderState desc, CoreShaderInfo coreShaderInfo, double camX, double camY, double camZ, Matrix4f viewProjection, ClientLevel level) {
+	protected P setup(ShaderState desc, CoreShaderInfo coreShaderInfo, double camX, double camY, double camZ, Matrix4f viewProjection, ClientLevel level, StateSnapshot ctx) {
 
 		VertexType vertexType = desc.vertex();
 		FileResolution instanceShader = desc.instance()
@@ -171,7 +173,7 @@ public class InstancingEngine<P extends WorldProgram> implements Engine {
 
 		P program = context.getProgram(new ProgramCompiler.Context(vertexType, instanceShader,
 				material.vertexShader(), material.fragmentShader(), coreShaderInfo.getAdjustedAlphaDiscard(),
-				coreShaderInfo.fogType(), GameStateRegistry.takeSnapshot()));
+				coreShaderInfo.fogType(), ctx));
 
 		program.bind();
 		program.uploadUniforms(camX, camY, camZ, viewProjection, level);