Less omissions in mesh emission

- Cannibalize shade separated vertex consumer to function as the mesh
  emitter for baked model buffering
- Create one MeshEmitter per chunk RenderType to allow more coherency
  during multi block buffering
- MeshEmitters own BufferBuilders, and the buffering functions call
  #begin on the mesh emitters directly
- Each time the emitter sees a quad with a different shade flag than the
  previous run of quads, it emits a mesh and begins again
- Finally, the buffering functions call #end on the mesh emitters to
  emit trailing meshes and clear transient state
- Add diffuse debug mode
- Order indirect draws by mesh index first
- Remove non-shade separated option from buffering utilities because it
  allows you to opt in to incorrect behaviour
- Remove TessellatedModel
- Document mesh ordering contract in Model

src/main/java/com/jozufozu/flywheel/api/model/Model.java

@@ -7,6 +7,16 @@ import org.joml.Vector4fc;
 import com.jozufozu.flywheel.api.material.Material;
 
 public interface Model {
+	/**
+	 * Get a list of all meshes in this model.
+	 *
+	 * <p>The contents of the returned list will be queried, but never modified.</p>
+	 *
+	 * <p>Meshes will be rendered in the order they appear in this list, though
+	 * no render order guarantees are made for meshes between different models.</p>
+	 *
+	 * @return A list of meshes.
+	 */
 	List<ConfiguredMesh> meshes();
 
 	/**

src/main/java/com/jozufozu/flywheel/backend/engine/indirect/IndirectCullingGroup.java

@@ -33,6 +33,7 @@ import com.jozufozu.flywheel.backend.gl.shader.GlProgram;
 
 public class IndirectCullingGroup<I extends Instance> {
 	private static final Comparator<IndirectDraw> DRAW_COMPARATOR = Comparator.comparing(IndirectDraw::stage)
+			.thenComparing(IndirectDraw::indexOfMeshInModel)
 			.thenComparing(IndirectDraw::material, MaterialRenderState.COMPARATOR);
 
 	private static final int DRAW_BARRIER_BITS = GL_SHADER_STORAGE_BARRIER_BIT | GL_COMMAND_BARRIER_BIT;
@@ -179,9 +180,12 @@ public class IndirectCullingGroup<I extends Instance> {
         instancer.index = instancers.size();
 		instancers.add(instancer);
 
-		for (var entry : model.meshes()) {
+        List<Model.ConfiguredMesh> meshes = model.meshes();
+        for (int i = 0; i < meshes.size(); i++) {
+            var entry = meshes.get(i);
+
             MeshPool.PooledMesh mesh = meshPool.alloc(entry.mesh());
-			var draw = new IndirectDraw(instancer, entry.material(), mesh, stage);
+            var draw = new IndirectDraw(instancer, entry.material(), mesh, stage, i);
             indirectDraws.add(draw);
             instancer.addDraw(draw);
         }

src/main/java/com/jozufozu/flywheel/backend/engine/indirect/IndirectDraw.java

@@ -13,6 +13,7 @@ public class IndirectDraw {
 	private final Material material;
 	private final MeshPool.PooledMesh mesh;
 	private final RenderStage stage;
+	private final int indexOfMeshInModel;
 
 	private final int materialVertexIndex;
 	private final int materialFragmentIndex;
@@ -20,11 +21,12 @@ public class IndirectDraw {
 	private final int packedMaterialProperties;
 	private boolean deleted;
 
-	public IndirectDraw(IndirectInstancer<?> model, Material material, MeshPool.PooledMesh mesh, RenderStage stage) {
+	public IndirectDraw(IndirectInstancer<?> model, Material material, MeshPool.PooledMesh mesh, RenderStage stage, int indexOfMeshInModel) {
 		this.model = model;
 		this.material = material;
 		this.mesh = mesh;
 		this.stage = stage;
+		this.indexOfMeshInModel = indexOfMeshInModel;
 
 		mesh.acquire();
 
@@ -50,6 +52,10 @@ public class IndirectDraw {
 		return stage;
 	}
 
+	public int indexOfMeshInModel() {
+		return indexOfMeshInModel;
+	}
+
 	public void write(long ptr) {
 		MemoryUtil.memPutInt(ptr, mesh.indexCount()); // count
 		MemoryUtil.memPutInt(ptr + 4, 0); // instanceCount - to be set by the apply shader

src/main/java/com/jozufozu/flywheel/config/DebugMode.java

@@ -7,5 +7,6 @@ public enum DebugMode {
 	LIGHT_LEVEL,
 	LIGHT_COLOR,
 	OVERLAY,
+	DIFFUSE,
 	LIGHT_VOLUME,
 }

src/main/java/com/jozufozu/flywheel/lib/model/baked/BakedModelBufferer.java

@@ -7,9 +7,7 @@ import org.jetbrains.annotations.Nullable;
 
 import com.mojang.blaze3d.vertex.BufferBuilder;
 import com.mojang.blaze3d.vertex.BufferBuilder.RenderedBuffer;
-import com.mojang.blaze3d.vertex.DefaultVertexFormat;
 import com.mojang.blaze3d.vertex.PoseStack;
-import com.mojang.blaze3d.vertex.VertexFormat;
 
 import net.minecraft.client.renderer.ItemBlockRenderTypes;
 import net.minecraft.client.renderer.RenderType;
@@ -41,7 +39,7 @@ final class BakedModelBufferer {
 			poseStack = objects.identityPoseStack;
 		}
 		RandomSource random = objects.random;
-		BufferBuilder[] buffers = objects.shadedBuffers;
+		var consumers = objects.emitters;
 
 		modelData = model.getModelData(renderWorld, BlockPos.ZERO, state, modelData);
 		random.setSeed(42L);
@@ -49,63 +47,17 @@ final class BakedModelBufferer {
 
 		for (RenderType renderType : renderTypes) {
 			int layerIndex = renderType.getChunkLayerId();
+			var consumer = consumers[layerIndex];
 
-			BufferBuilder buffer = buffers[layerIndex];
+			consumer.begin(resultConsumer);
-			buffer.begin(VertexFormat.Mode.QUADS, DefaultVertexFormat.BLOCK);
 
 			poseStack.pushPose();
-			blockRenderer.tesselateBlock(renderWorld, model, state, BlockPos.ZERO, poseStack, buffer, false, random, 42L, OverlayTexture.NO_OVERLAY, modelData, renderType);
+			blockRenderer.tesselateBlock(renderWorld, model, state, BlockPos.ZERO, poseStack, consumer, false, random, 42L, OverlayTexture.NO_OVERLAY, modelData, renderType);
 			poseStack.popPose();
 
-			RenderedBuffer data = buffer.endOrDiscardIfEmpty();
+			consumer.end();
-			if (data != null) {
-				resultConsumer.accept(renderType, data);
-				data.release();
 		}
 	}
-	}
-
-	public static void bufferSingleShadeSeparated(ModelBlockRenderer blockRenderer, BlockAndTintGetter renderWorld, BakedModel model, BlockState state, @Nullable PoseStack poseStack, ModelData modelData, ShadeSeparatedResultConsumer resultConsumer) {
-		ThreadLocalObjects objects = THREAD_LOCAL_OBJECTS.get();
-		if (poseStack == null) {
-			poseStack = objects.identityPoseStack;
-		}
-		RandomSource random = objects.random;
-		ShadeSeparatingVertexConsumer shadeSeparatingWrapper = objects.shadeSeparatingWrapper;
-		BufferBuilder[] shadedBuffers = objects.shadedBuffers;
-		BufferBuilder[] unshadedBuffers = objects.unshadedBuffers;
-
-		modelData = model.getModelData(renderWorld, BlockPos.ZERO, state, modelData);
-		random.setSeed(42L);
-		ChunkRenderTypeSet renderTypes = model.getRenderTypes(state, random, modelData);
-
-		for (RenderType renderType : renderTypes) {
-			int layerIndex = renderType.getChunkLayerId();
-
-			BufferBuilder shadedBuffer = shadedBuffers[layerIndex];
-			BufferBuilder unshadedBuffer = unshadedBuffers[layerIndex];
-			shadeSeparatingWrapper.prepare(shadedBuffer, unshadedBuffer);
-			shadedBuffer.begin(VertexFormat.Mode.QUADS, DefaultVertexFormat.BLOCK);
-			unshadedBuffer.begin(VertexFormat.Mode.QUADS, DefaultVertexFormat.BLOCK);
-
-			poseStack.pushPose();
-			blockRenderer.tesselateBlock(renderWorld, model, state, BlockPos.ZERO, poseStack, shadeSeparatingWrapper, false, random, 42L, OverlayTexture.NO_OVERLAY, modelData, renderType);
-			poseStack.popPose();
-
-			RenderedBuffer shadedData = shadedBuffer.endOrDiscardIfEmpty();
-			if (shadedData != null) {
-				resultConsumer.accept(renderType, true, shadedData);
-				shadedData.release();
-			}
-			RenderedBuffer unshadedData = unshadedBuffer.endOrDiscardIfEmpty();
-			if (unshadedData != null) {
-				resultConsumer.accept(renderType, false, unshadedData);
-				unshadedData.release();
-			}
-		}
-
-		shadeSeparatingWrapper.clear();
-	}
 
 	public static void bufferBlock(BlockRenderDispatcher renderDispatcher, BlockAndTintGetter renderWorld, BlockState state, @Nullable PoseStack poseStack, ModelData modelData, ResultConsumer resultConsumer) {
 		if (state.getRenderShape() != RenderShape.MODEL) {
@@ -115,14 +67,6 @@ final class BakedModelBufferer {
 		bufferSingle(renderDispatcher.getModelRenderer(), renderWorld, renderDispatcher.getBlockModel(state), state, poseStack, modelData, resultConsumer);
 	}
 
-	public static void bufferBlockShadeSeparated(BlockRenderDispatcher renderDispatcher, BlockAndTintGetter renderWorld, BlockState state, @Nullable PoseStack poseStack, ModelData modelData, ShadeSeparatedResultConsumer resultConsumer) {
-		if (state.getRenderShape() != RenderShape.MODEL) {
-			return;
-		}
-
-		bufferSingleShadeSeparated(renderDispatcher.getModelRenderer(), renderWorld, renderDispatcher.getBlockModel(state), state, poseStack, modelData, resultConsumer);
-	}
-
 	public static void bufferMultiBlock(BlockRenderDispatcher renderDispatcher, Iterator<BlockPos> posIterator, BlockAndTintGetter renderWorld, @Nullable PoseStack poseStack, Function<BlockPos, ModelData> modelDataLookup, boolean renderFluids, ResultConsumer resultConsumer) {
 		ThreadLocalObjects objects = THREAD_LOCAL_OBJECTS.get();
 		if (poseStack == null) {
@@ -131,9 +75,10 @@ final class BakedModelBufferer {
 		RandomSource random = objects.random;
 		TransformingVertexConsumer transformingWrapper = objects.transformingWrapper;
 
-		BufferBuilder[] buffers = objects.shadedBuffers;
+		var emitters = objects.emitters;
-		for (BufferBuilder buffer : buffers) {
+
-			buffer.begin(VertexFormat.Mode.QUADS, DefaultVertexFormat.BLOCK);
+		for (var emitter : emitters) {
+			emitter.begin(resultConsumer);
 		}
 
 		ModelBlockRenderer blockRenderer = renderDispatcher.getModelRenderer();
@@ -150,7 +95,7 @@ final class BakedModelBufferer {
 					RenderType layer = ItemBlockRenderTypes.getRenderLayer(fluidState);
 					int layerIndex = layer.getChunkLayerId();
 
-					transformingWrapper.prepare(buffers[layerIndex], poseStack);
+					transformingWrapper.prepare(emitters[layerIndex], poseStack);
 
 					poseStack.pushPose();
 					poseStack.translate(pos.getX() - (pos.getX() & 0xF), pos.getY() - (pos.getY() & 0xF), pos.getZ() - (pos.getZ() & 0xF));
@@ -170,11 +115,9 @@ final class BakedModelBufferer {
 				for (RenderType renderType : renderTypes) {
 					int layerIndex = renderType.getChunkLayerId();
 
-					BufferBuilder buffer = buffers[layerIndex];
-	
 					poseStack.pushPose();
 					poseStack.translate(pos.getX(), pos.getY(), pos.getZ());
-					blockRenderer.tesselateBlock(renderWorld, model, state, pos, poseStack, buffer, true, random, seed, OverlayTexture.NO_OVERLAY, modelData, renderType);
+					blockRenderer.tesselateBlock(renderWorld, model, state, pos, poseStack, emitters[layerIndex], true, random, seed, OverlayTexture.NO_OVERLAY, modelData, renderType);
 					poseStack.popPose();
 				}
 			}
@@ -182,108 +125,14 @@ final class BakedModelBufferer {
 
 		ModelBlockRenderer.clearCache();
 
+		for (var emitter : emitters) {
+			emitter.end();
+		}
+
 		transformingWrapper.clear();
-
-		for (int layerIndex = 0; layerIndex < CHUNK_LAYER_AMOUNT; layerIndex++) {
-			RenderType renderType = CHUNK_LAYERS[layerIndex];
-			BufferBuilder buffer = buffers[layerIndex];
-			RenderedBuffer data = buffer.endOrDiscardIfEmpty();
-			if (data != null) {
-				resultConsumer.accept(renderType, data);
-				data.release();
-			}
-		}
-	}
-
-	public static void bufferMultiBlockShadeSeparated(BlockRenderDispatcher renderDispatcher, Iterator<BlockPos> posIterator, BlockAndTintGetter renderWorld, @Nullable PoseStack poseStack, Function<BlockPos, ModelData> modelDataLookup, boolean renderFluids, ShadeSeparatedResultConsumer resultConsumer) {
-		ThreadLocalObjects objects = THREAD_LOCAL_OBJECTS.get();
-		if (poseStack == null) {
-			poseStack = objects.identityPoseStack;
-		}
-		RandomSource random = objects.random;
-		ShadeSeparatingVertexConsumer shadeSeparatingWrapper = objects.shadeSeparatingWrapper;
-		TransformingVertexConsumer transformingWrapper = objects.transformingWrapper;
-
-		BufferBuilder[] shadedBuffers = objects.shadedBuffers;
-		BufferBuilder[] unshadedBuffers = objects.unshadedBuffers;
-		for (BufferBuilder buffer : shadedBuffers) {
-			buffer.begin(VertexFormat.Mode.QUADS, DefaultVertexFormat.BLOCK);
-		}
-		for (BufferBuilder buffer : unshadedBuffers) {
-			buffer.begin(VertexFormat.Mode.QUADS, DefaultVertexFormat.BLOCK);
-		}
-
-		ModelBlockRenderer blockRenderer = renderDispatcher.getModelRenderer();
-		ModelBlockRenderer.enableCaching();
-
-		while (posIterator.hasNext()) {
-			BlockPos pos = posIterator.next();
-			BlockState state = renderWorld.getBlockState(pos);
-
-			if (renderFluids) {
-				FluidState fluidState = state.getFluidState();
-	
-				if (!fluidState.isEmpty()) {
-					RenderType layer = ItemBlockRenderTypes.getRenderLayer(fluidState);
-					int layerIndex = layer.getChunkLayerId();
-					
-					transformingWrapper.prepare(shadedBuffers[layerIndex], poseStack);
-
-					poseStack.pushPose();
-					poseStack.translate(pos.getX() - (pos.getX() & 0xF), pos.getY() - (pos.getY() & 0xF), pos.getZ() - (pos.getZ() & 0xF));
-					renderDispatcher.renderLiquid(pos, renderWorld, transformingWrapper, state, fluidState);
-					poseStack.popPose();
-				}
-			}
-
-			if (state.getRenderShape() == RenderShape.MODEL) {
-				long seed = state.getSeed(pos);
-				BakedModel model = renderDispatcher.getBlockModel(state);
-				ModelData modelData = modelDataLookup.apply(pos);
-				modelData = model.getModelData(renderWorld, pos, state, modelData);
-				random.setSeed(seed);
-				ChunkRenderTypeSet renderTypes = model.getRenderTypes(state, random, modelData);
-
-				for (RenderType renderType : renderTypes) {
-					int layerIndex = renderType.getChunkLayerId();
-
-					shadeSeparatingWrapper.prepare(shadedBuffers[layerIndex], unshadedBuffers[layerIndex]);
-
-					poseStack.pushPose();
-					poseStack.translate(pos.getX(), pos.getY(), pos.getZ());
-					blockRenderer.tesselateBlock(renderWorld, model, state, pos, poseStack, shadeSeparatingWrapper, true, random, seed, OverlayTexture.NO_OVERLAY, modelData, renderType);
-					poseStack.popPose();
-				}
-			}
-		}
-
-		ModelBlockRenderer.clearCache();
-
-		shadeSeparatingWrapper.clear();
-		transformingWrapper.clear();
-
-		for (int layerIndex = 0; layerIndex < CHUNK_LAYER_AMOUNT; layerIndex++) {
-			RenderType renderType = CHUNK_LAYERS[layerIndex];
-			BufferBuilder shadedBuffer = shadedBuffers[layerIndex];
-			BufferBuilder unshadedBuffer = unshadedBuffers[layerIndex];
-			RenderedBuffer shadedData = shadedBuffer.endOrDiscardIfEmpty();
-			if (shadedData != null) {
-				resultConsumer.accept(renderType, true, shadedData);
-				shadedData.release();
-			}
-			RenderedBuffer unshadedData = unshadedBuffer.endOrDiscardIfEmpty();
-			if (unshadedData != null) {
-				resultConsumer.accept(renderType, false, unshadedData);
-				unshadedData.release();
-			}
-		}
 	}
 
 	public interface ResultConsumer {
-		void accept(RenderType renderType, RenderedBuffer data);
-	}
-
-	public interface ShadeSeparatedResultConsumer {
 		void accept(RenderType renderType, boolean shaded, RenderedBuffer data);
 	}
 
@@ -291,17 +140,16 @@ final class BakedModelBufferer {
 		public final PoseStack identityPoseStack = new PoseStack();
 		public final RandomSource random = RandomSource.createNewThreadLocalInstance();
 
-		public final ShadeSeparatingVertexConsumer shadeSeparatingWrapper = new ShadeSeparatingVertexConsumer();
 		public final TransformingVertexConsumer transformingWrapper = new TransformingVertexConsumer();
 
-		public final BufferBuilder[] shadedBuffers = new BufferBuilder[CHUNK_LAYER_AMOUNT];
+		public final MeshEmitter[] emitters = new MeshEmitter[CHUNK_LAYER_AMOUNT];
-		public final BufferBuilder[] unshadedBuffers = new BufferBuilder[CHUNK_LAYER_AMOUNT];
 
 		{
 			for (int layerIndex = 0; layerIndex < CHUNK_LAYER_AMOUNT; layerIndex++) {
-				int initialSize = CHUNK_LAYERS[layerIndex].bufferSize();
+				var renderType = CHUNK_LAYERS[layerIndex];
-				shadedBuffers[layerIndex] = new BufferBuilder(initialSize);
+				// FIXME: We leak the memory owned by the BufferBuilder here.
-				unshadedBuffers[layerIndex] = new BufferBuilder(initialSize);
+				var buffer = new BufferBuilder(renderType.bufferSize());
+				emitters[layerIndex] = new MeshEmitter(buffer, renderType);
 			}
 		}
 	}

src/main/java/com/jozufozu/flywheel/lib/model/baked/BakedModelBuilder.java

@@ -2,6 +2,8 @@ package com.jozufozu.flywheel.lib.model.baked;
 
 import java.util.function.BiFunction;
 
+import org.jetbrains.annotations.Nullable;
+
 import com.google.common.collect.ImmutableList;
 import com.jozufozu.flywheel.api.material.Material;
 import com.jozufozu.flywheel.api.model.Model;
@@ -9,8 +11,8 @@ import com.jozufozu.flywheel.api.vertex.VertexView;
 import com.jozufozu.flywheel.lib.memory.MemoryBlock;
 import com.jozufozu.flywheel.lib.model.ModelUtil;
 import com.jozufozu.flywheel.lib.model.SimpleMesh;
+import com.jozufozu.flywheel.lib.model.SimpleModel;
 import com.jozufozu.flywheel.lib.model.baked.BakedModelBufferer.ResultConsumer;
-import com.jozufozu.flywheel.lib.model.baked.BakedModelBufferer.ShadeSeparatedResultConsumer;
 import com.jozufozu.flywheel.lib.vertex.NoOverlayVertexView;
 import com.mojang.blaze3d.vertex.PoseStack;
 
@@ -23,11 +25,15 @@ import net.minecraftforge.client.model.data.ModelData;
 
 public class BakedModelBuilder {
 	private final BakedModel bakedModel;
+	@Nullable
 	private BlockAndTintGetter renderWorld;
+	@Nullable
 	private BlockState blockState;
+	@Nullable
 	private PoseStack poseStack;
+	@Nullable
 	private ModelData modelData;
-	private boolean shadeSeparated = true;
+	@Nullable
 	private BiFunction<RenderType, Boolean, Material> materialFunc;
 
 	public BakedModelBuilder(BakedModel bakedModel) {
@@ -54,17 +60,12 @@ public class BakedModelBuilder {
 		return this;
 	}
 
-	public BakedModelBuilder disableShadeSeparation() {
-		shadeSeparated = false;
-		return this;
-	}
-
 	public BakedModelBuilder materialFunc(BiFunction<RenderType, Boolean, Material> materialFunc) {
 		this.materialFunc = materialFunc;
 		return this;
 	}
 
-	public TessellatedModel build() {
+	public SimpleModel build() {
 		if (renderWorld == null) {
 			renderWorld = VirtualEmptyBlockGetter.INSTANCE;
 		}
@@ -80,8 +81,7 @@ public class BakedModelBuilder {
 
 		var out = ImmutableList.<Model.ConfiguredMesh>builder();
 
-		if (shadeSeparated) {
+		ResultConsumer resultConsumer = (renderType, shaded, data) -> {
-			ShadeSeparatedResultConsumer resultConsumer = (renderType, shaded, data) -> {
 			Material material = materialFunc.apply(renderType, shaded);
 			if (material != null) {
 				VertexView vertexView = new NoOverlayVertexView();
@@ -90,20 +90,8 @@ public class BakedModelBuilder {
 				out.add(new Model.ConfiguredMesh(material, mesh));
 			}
 		};
-			BakedModelBufferer.bufferSingleShadeSeparated(ModelUtil.VANILLA_RENDERER.getModelRenderer(), renderWorld, bakedModel, blockState, poseStack, modelData, resultConsumer);
-		} else {
-			ResultConsumer resultConsumer = (renderType, data) -> {
-				Material material = materialFunc.apply(renderType, true);
-				if (material != null) {
-					VertexView vertexView = new NoOverlayVertexView();
-					MemoryBlock meshData = ModelUtil.convertVanillaBuffer(data, vertexView);
-					var mesh = new SimpleMesh(vertexView, meshData, "source=BakedModelBuilder," + "bakedModel=" + bakedModel + ",renderType=" + renderType);
-					out.add(new Model.ConfiguredMesh(material, mesh));
-				}
-			};
 		BakedModelBufferer.bufferSingle(ModelUtil.VANILLA_RENDERER.getModelRenderer(), renderWorld, bakedModel, blockState, poseStack, modelData, resultConsumer);
-		}
 
-		return new TessellatedModel(out.build(), shadeSeparated);
+		return new SimpleModel(out.build());
 	}
 }

src/main/java/com/jozufozu/flywheel/lib/model/baked/BlockModelBuilder.java

@@ -2,6 +2,8 @@ package com.jozufozu.flywheel.lib.model.baked;
 
 import java.util.function.BiFunction;
 
+import org.jetbrains.annotations.Nullable;
+
 import com.google.common.collect.ImmutableList;
 import com.jozufozu.flywheel.api.material.Material;
 import com.jozufozu.flywheel.api.model.Model;
@@ -9,8 +11,8 @@ import com.jozufozu.flywheel.api.vertex.VertexView;
 import com.jozufozu.flywheel.lib.memory.MemoryBlock;
 import com.jozufozu.flywheel.lib.model.ModelUtil;
 import com.jozufozu.flywheel.lib.model.SimpleMesh;
+import com.jozufozu.flywheel.lib.model.SimpleModel;
 import com.jozufozu.flywheel.lib.model.baked.BakedModelBufferer.ResultConsumer;
-import com.jozufozu.flywheel.lib.model.baked.BakedModelBufferer.ShadeSeparatedResultConsumer;
 import com.jozufozu.flywheel.lib.vertex.NoOverlayVertexView;
 import com.mojang.blaze3d.vertex.PoseStack;
 
@@ -21,10 +23,13 @@ import net.minecraftforge.client.model.data.ModelData;
 
 public class BlockModelBuilder {
 	private final BlockState state;
+	@Nullable
 	private BlockAndTintGetter renderWorld;
+	@Nullable
 	private PoseStack poseStack;
+	@Nullable
 	private ModelData modelData;
-	private boolean shadeSeparated = true;
+	@Nullable
 	private BiFunction<RenderType, Boolean, Material> materialFunc;
 
 	public BlockModelBuilder(BlockState state) {
@@ -46,17 +51,12 @@ public class BlockModelBuilder {
 		return this;
 	}
 
-	public BlockModelBuilder disableShadeSeparation() {
-		shadeSeparated = false;
-		return this;
-	}
-
 	public BlockModelBuilder materialFunc(BiFunction<RenderType, Boolean, Material> materialFunc) {
 		this.materialFunc = materialFunc;
 		return this;
 	}
 
-	public TessellatedModel build() {
+	public SimpleModel build() {
 		if (renderWorld == null) {
 			renderWorld = VirtualEmptyBlockGetter.INSTANCE;
 		}
@@ -69,8 +69,7 @@ public class BlockModelBuilder {
 
 		var out = ImmutableList.<Model.ConfiguredMesh>builder();
 
-		if (shadeSeparated) {
+		ResultConsumer resultConsumer = (renderType, shaded, data) -> {
-			ShadeSeparatedResultConsumer resultConsumer = (renderType, shaded, data) -> {
 			Material material = materialFunc.apply(renderType, shaded);
 			if (material != null) {
 				VertexView vertexView = new NoOverlayVertexView();
@@ -79,20 +78,8 @@ public class BlockModelBuilder {
 				out.add(new Model.ConfiguredMesh(material, mesh));
 			}
 		};
-			BakedModelBufferer.bufferBlockShadeSeparated(ModelUtil.VANILLA_RENDERER, renderWorld, state, poseStack, modelData, resultConsumer);
-		} else {
-			ResultConsumer resultConsumer = (renderType, data) -> {
-				Material material = materialFunc.apply(renderType, true);
-				if (material != null) {
-					VertexView vertexView = new NoOverlayVertexView();
-					MemoryBlock meshData = ModelUtil.convertVanillaBuffer(data, vertexView);
-					var mesh = new SimpleMesh(vertexView, meshData, "source=BlockModelBuilder," + "blockState=" + state + ",renderType=" + renderType);
-					out.add(new Model.ConfiguredMesh(material, mesh));
-				}
-			};
 		BakedModelBufferer.bufferBlock(ModelUtil.VANILLA_RENDERER, renderWorld, state, poseStack, modelData, resultConsumer);
-		}
 
-		return new TessellatedModel(out.build(), shadeSeparated);
+		return new SimpleModel(out.build());
 	}
 }

src/main/java/com/jozufozu/flywheel/lib/model/baked/MeshEmitter.java

@@ -0,0 +1,122 @@
+package com.jozufozu.flywheel.lib.model.baked;
+
+import org.jetbrains.annotations.Nullable;
+
+import com.mojang.blaze3d.vertex.BufferBuilder;
+import com.mojang.blaze3d.vertex.DefaultVertexFormat;
+import com.mojang.blaze3d.vertex.PoseStack;
+import com.mojang.blaze3d.vertex.VertexConsumer;
+import com.mojang.blaze3d.vertex.VertexFormat;
+
+import net.minecraft.client.renderer.RenderType;
+import net.minecraft.client.renderer.block.model.BakedQuad;
+
+class MeshEmitter implements VertexConsumer {
+	private final BufferBuilder bufferBuilder;
+	private final RenderType renderType;
+	private boolean lastQuadWasShaded;
+	private boolean seenFirstQuad;
+	@Nullable
+	private BakedModelBufferer.ResultConsumer resultConsumer;
+
+    MeshEmitter(BufferBuilder bufferBuilder, RenderType renderType) {
+        this.bufferBuilder = bufferBuilder;
+        this.renderType = renderType;
+    }
+
+	public void begin(BakedModelBufferer.ResultConsumer resultConsumer) {
+		this.resultConsumer = resultConsumer;
+
+		begin();
+	}
+
+	public void end() {
+		emit();
+		seenFirstQuad = false;
+		resultConsumer = null;
+	}
+
+	private void begin() {
+		bufferBuilder.begin(VertexFormat.Mode.QUADS, DefaultVertexFormat.BLOCK);
+	}
+
+	private void emit() {
+		var renderedBuffer = bufferBuilder.endOrDiscardIfEmpty();
+
+		if (renderedBuffer != null) {
+			if (resultConsumer != null) {
+				resultConsumer.accept(renderType, lastQuadWasShaded, renderedBuffer);
+			}
+			renderedBuffer.release();
+		}
+	}
+
+	private void observeQuadAndEmitIfNecessary(BakedQuad quad) {
+		if (seenFirstQuad && lastQuadWasShaded != quad.isShade()) {
+			emit();
+			begin();
+		}
+
+		seenFirstQuad = true;
+		lastQuadWasShaded = quad.isShade();
+	}
+
+	@Override
+	public void putBulkData(PoseStack.Pose poseEntry, BakedQuad quad, float[] colorMuls, float red, float green, float blue, int[] combinedLights, int combinedOverlay, boolean mulColor) {
+		observeQuadAndEmitIfNecessary(quad);
+
+		bufferBuilder.putBulkData(poseEntry, quad, colorMuls, red, green, blue, combinedLights, combinedOverlay, mulColor);
+	}
+
+	@Override
+	public void putBulkData(PoseStack.Pose matrixEntry, BakedQuad quad, float[] baseBrightness, float red, float green, float blue, float alpha, int[] lightmapCoords, int overlayCoords, boolean readExistingColor) {
+		observeQuadAndEmitIfNecessary(quad);
+
+		bufferBuilder.putBulkData(matrixEntry, quad, baseBrightness, red, green, blue, alpha, lightmapCoords, overlayCoords, readExistingColor);
+	}
+
+	@Override
+	public VertexConsumer vertex(double x, double y, double z) {
+		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
+	}
+
+	@Override
+	public VertexConsumer color(int red, int green, int blue, int alpha) {
+		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
+	}
+
+	@Override
+	public VertexConsumer uv(float u, float v) {
+		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
+	}
+
+	@Override
+	public VertexConsumer overlayCoords(int u, int v) {
+		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
+	}
+
+	@Override
+	public VertexConsumer uv2(int u, int v) {
+		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
+	}
+
+	@Override
+	public VertexConsumer normal(float x, float y, float z) {
+		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
+	}
+
+	@Override
+	public void endVertex() {
+		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
+	}
+
+	@Override
+	public void defaultColor(int red, int green, int blue, int alpha) {
+		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
+	}
+
+	@Override
+	public void unsetDefaultColor() {
+		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
+	}
+}

src/main/java/com/jozufozu/flywheel/lib/model/baked/MultiBlockModelBuilder.java

@@ -3,6 +3,8 @@ package com.jozufozu.flywheel.lib.model.baked;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
+import org.jetbrains.annotations.Nullable;
+
 import com.google.common.collect.ImmutableList;
 import com.jozufozu.flywheel.api.material.Material;
 import com.jozufozu.flywheel.api.model.Model;
@@ -10,8 +12,8 @@ import com.jozufozu.flywheel.api.vertex.VertexView;
 import com.jozufozu.flywheel.lib.memory.MemoryBlock;
 import com.jozufozu.flywheel.lib.model.ModelUtil;
 import com.jozufozu.flywheel.lib.model.SimpleMesh;
+import com.jozufozu.flywheel.lib.model.SimpleModel;
 import com.jozufozu.flywheel.lib.model.baked.BakedModelBufferer.ResultConsumer;
-import com.jozufozu.flywheel.lib.model.baked.BakedModelBufferer.ShadeSeparatedResultConsumer;
 import com.jozufozu.flywheel.lib.vertex.NoOverlayVertexView;
 import com.mojang.blaze3d.vertex.PoseStack;
 
@@ -23,10 +25,12 @@ import net.minecraftforge.client.model.data.ModelData;
 public class MultiBlockModelBuilder {
 	private final BlockAndTintGetter renderWorld;
 	private final Iterable<BlockPos> positions;
+	@Nullable
 	private PoseStack poseStack;
+	@Nullable
 	private Function<BlockPos, ModelData> modelDataLookup;
 	private boolean renderFluids = false;
-	private boolean shadeSeparated = true;
+	@Nullable
 	private BiFunction<RenderType, Boolean, Material> materialFunc;
 
 	public MultiBlockModelBuilder(BlockAndTintGetter renderWorld, Iterable<BlockPos> positions) {
@@ -49,17 +53,12 @@ public class MultiBlockModelBuilder {
 		return this;
 	}
 
-	public MultiBlockModelBuilder disableShadeSeparation() {
-		shadeSeparated = false;
-		return this;
-	}
-
 	public MultiBlockModelBuilder materialFunc(BiFunction<RenderType, Boolean, Material> materialFunc) {
 		this.materialFunc = materialFunc;
 		return this;
 	}
 
-	public TessellatedModel build() {
+	public SimpleModel build() {
 		if (modelDataLookup == null) {
 			modelDataLookup = pos -> ModelData.EMPTY;
 		}
@@ -69,8 +68,7 @@ public class MultiBlockModelBuilder {
 
 		var out = ImmutableList.<Model.ConfiguredMesh>builder();
 
-		if (shadeSeparated) {
+		ResultConsumer resultConsumer = (renderType, shaded, data) -> {
-			ShadeSeparatedResultConsumer resultConsumer = (renderType, shaded, data) -> {
 			Material material = materialFunc.apply(renderType, shaded);
 			if (material != null) {
 				VertexView vertexView = new NoOverlayVertexView();
@@ -79,20 +77,8 @@ public class MultiBlockModelBuilder {
 				out.add(new Model.ConfiguredMesh(material, mesh));
 			}
 		};
-			BakedModelBufferer.bufferMultiBlockShadeSeparated(ModelUtil.VANILLA_RENDERER, positions.iterator(), renderWorld, poseStack, modelDataLookup, renderFluids, resultConsumer);
-		} else {
-			ResultConsumer resultConsumer = (renderType, data) -> {
-				Material material = materialFunc.apply(renderType, true);
-				if (material != null) {
-					VertexView vertexView = new NoOverlayVertexView();
-					MemoryBlock meshData = ModelUtil.convertVanillaBuffer(data, vertexView);
-					var mesh = new SimpleMesh(vertexView, meshData, "source=MultiBlockModelBuilder," + "renderType=" + renderType);
-					out.add(new Model.ConfiguredMesh(material, mesh));
-				}
-			};
 		BakedModelBufferer.bufferMultiBlock(ModelUtil.VANILLA_RENDERER, positions.iterator(), renderWorld, poseStack, modelDataLookup, renderFluids, resultConsumer);
-		}
 
-		return new TessellatedModel(out.build(), shadeSeparated);
+		return new SimpleModel(out.build());
 	}
 }

src/main/java/com/jozufozu/flywheel/lib/model/baked/ShadeSeparatingVertexConsumer.java

@@ -1,84 +0,0 @@
-package com.jozufozu.flywheel.lib.model.baked;
-
-import com.mojang.blaze3d.vertex.PoseStack;
-import com.mojang.blaze3d.vertex.VertexConsumer;
-
-import net.minecraft.client.renderer.block.model.BakedQuad;
-
-class ShadeSeparatingVertexConsumer implements VertexConsumer {
-	private VertexConsumer shadedConsumer;
-	private VertexConsumer unshadedConsumer;
-
-	public void prepare(VertexConsumer shadedConsumer, VertexConsumer unshadedConsumer) {
-		this.shadedConsumer = shadedConsumer;
-		this.unshadedConsumer = unshadedConsumer;
-	}
-
-	public void clear() {
-		shadedConsumer = null;
-		unshadedConsumer = null;
-	}
-
-	@Override
-	public void putBulkData(PoseStack.Pose poseEntry, BakedQuad quad, float[] colorMuls, float red, float green, float blue, int[] combinedLights, int combinedOverlay, boolean mulColor) {
-		if (quad.isShade()) {
-			shadedConsumer.putBulkData(poseEntry, quad, colorMuls, red, green, blue, combinedLights, combinedOverlay, mulColor);
-		} else {
-			unshadedConsumer.putBulkData(poseEntry, quad, colorMuls, red, green, blue, combinedLights, combinedOverlay, mulColor);
-		}
-	}
-
-	@Override
-	public void putBulkData(PoseStack.Pose matrixEntry, BakedQuad bakedQuad, float[] baseBrightness, float red, float green, float blue, float alpha, int[] lightmapCoords, int overlayCoords, boolean readExistingColor) {
-		if (bakedQuad.isShade()) {
-			shadedConsumer.putBulkData(matrixEntry, bakedQuad, baseBrightness, red, green, blue, alpha, lightmapCoords, overlayCoords, readExistingColor);
-		} else {
-			unshadedConsumer.putBulkData(matrixEntry, bakedQuad, baseBrightness, red, green, blue, alpha, lightmapCoords, overlayCoords, readExistingColor);
-		}
-	}
-
-	@Override
-	public VertexConsumer vertex(double x, double y, double z) {
-		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
-	}
-
-	@Override
-	public VertexConsumer color(int red, int green, int blue, int alpha) {
-		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
-	}
-
-	@Override
-	public VertexConsumer uv(float u, float v) {
-		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
-	}
-
-	@Override
-	public VertexConsumer overlayCoords(int u, int v) {
-		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
-	}
-
-	@Override
-	public VertexConsumer uv2(int u, int v) {
-		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
-	}
-
-	@Override
-	public VertexConsumer normal(float x, float y, float z) {
-		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
-	}
-
-	@Override
-	public void endVertex() {
-		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
-	}
-
-	@Override
-	public void defaultColor(int red, int green, int blue, int alpha) {
-		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
-	}
-
-	@Override
-	public void unsetDefaultColor() {
-		throw new UnsupportedOperationException("ShadeSeparatingVertexConsumer only supports putBulkData!");
-	}
-}

src/main/java/com/jozufozu/flywheel/lib/model/baked/TessellatedModel.java

@@ -1,17 +0,0 @@
-package com.jozufozu.flywheel.lib.model.baked;
-
-import com.google.common.collect.ImmutableList;
-import com.jozufozu.flywheel.lib.model.SimpleModel;
-
-public class TessellatedModel extends SimpleModel {
-	private final boolean shadeSeparated;
-
-	public TessellatedModel(ImmutableList<ConfiguredMesh> meshes, boolean shadeSeparated) {
-		super(meshes);
-		this.shadeSeparated = shadeSeparated;
-	}
-
-	public boolean isShadeSeparated() {
-		return shadeSeparated;
-	}
-}

src/main/resources/assets/flywheel/flywheel/internal/common.frag

@@ -25,6 +25,18 @@ flat in uint _flw_instanceID;
 
 out vec4 _flw_outputColor;
 
+float _flw_diffuseFactor() {
+    if (flw_material.diffuse) {
+        if (flw_constantAmbientLight == 1u) {
+            return diffuseNether(flw_vertexNormal);
+        } else {
+            return diffuse(flw_vertexNormal);
+        }
+    } else {
+        return 1.;
+    }
+}
+
 void _flw_main() {
     flw_sampleColor = texture(flw_diffuseTex, flw_vertexTexCoord);
     flw_fragColor = flw_vertexColor * flw_sampleColor;
@@ -49,15 +61,8 @@ void _flw_main() {
 
     vec4 color = flw_fragColor;
 
-    if (flw_material.diffuse) {
+    float diffuseFactor = _flw_diffuseFactor();
-        float diffuseFactor;
-        if (flw_constantAmbientLight == 1u) {
-            diffuseFactor = diffuseNether(flw_vertexNormal);
-        } else {
-            diffuseFactor = diffuse(flw_vertexNormal);
-        }
     color.rgb *= diffuseFactor;
-    }
 
     if (flw_material.useOverlay) {
         vec4 overlayColor = texelFetch(flw_overlayTex, flw_fragOverlay, 0);
@@ -90,8 +95,11 @@ void _flw_main() {
         case 5u:
         color = vec4(flw_fragOverlay / 16., 0., 1.);
         break;
-        #ifdef _FLW_EMBEDDED
         case 6u:
+        color = vec4(vec3(diffuseFactor), 1.);
+        break;
+        #ifdef _FLW_EMBEDDED
+        case 7u:
         color = vec4(_flw_lightVolumeCoord, 1.);
         break;
         #endif