Add a new render state middleware

patches/net/minecraft/client/renderer/MultiBufferSource.java.patch

@@ -0,0 +1,11 @@
+--- a/net/minecraft/client/renderer/MultiBufferSource.java
++++ b/net/minecraft/client/renderer/MultiBufferSource.java
+@@ -14,7 +_,7 @@
+ import net.neoforged.api.distmarker.OnlyIn;
+
+ @OnlyIn(Dist.CLIENT)
+-public interface MultiBufferSource {
++public interface MultiBufferSource extends net.neoforged.neoforge.client.extensions.IMultiBufferSourceExtension {
+     static MultiBufferSource.BufferSource immediate(ByteBufferBuilder p_350664_) {
+         return immediateWithBuffers(Object2ObjectSortedMaps.emptyMap(), p_350664_);
+     }

patches/net/minecraft/client/renderer/RenderType.java.patch

@@ -1,9 +1,35 @@
 --- a/net/minecraft/client/renderer/RenderType.java
 +++ b/net/minecraft/client/renderer/RenderType.java
-@@ -1847,4 +_,16 @@
+@@ -1010,6 +_,15 @@
+             .createCompositeState(false)
+     );
+     public static final ImmutableList<RenderType> CHUNK_BUFFER_LAYERS = ImmutableList.of(solid(), cutoutMipped(), cutout(), translucent(), tripwire());
++    public static final ImmutableList<RenderType> NEOFORGE_CHUNK_BUFFER_LAYERS;
++    static {
++        net.neoforged.neoforge.client.buffer.chunk.ChunkBufferDefinitionManager.init();
++        ImmutableList.Builder<RenderType> builder = ImmutableList.builder();
++        builder.addAll(CHUNK_BUFFER_LAYERS);
++        builder.addAll(net.neoforged.neoforge.client.buffer.chunk.ChunkBufferDefinitionManager.getChunkBufferDefinitions().stream().map(net.neoforged.neoforge.client.buffer.VanillaBufferDefinitions::bakeVanillaRenderType).toList());
++        NEOFORGE_CHUNK_BUFFER_LAYERS = builder.build();
++    }
++
+     public final VertexFormat format;
+     public final VertexFormat.Mode mode;
+     public final int bufferSize;
+@@ -1545,7 +_,7 @@
+     }
+
+     public static List<RenderType> chunkBufferLayers() {
+-        return CHUNK_BUFFER_LAYERS;
++        return NEOFORGE_CHUNK_BUFFER_LAYERS;
+     }
+
+     public int bufferSize() {
+@@ -1846,5 +_,17 @@
+         public String toString() {
              return this.name;
          }
-     }
++    }
 +
 +    // Neo: Assign internal IDs for RenderType to be used in rendering
 +    private int chunkLayerId = -1;
@@ -15,5 +41,5 @@
 +        int i = 0;
 +        for (var layer : chunkBufferLayers())
 +            layer.chunkLayerId = i++;
-+    }
+     }
  }

patches/net/minecraft/client/renderer/chunk/SectionCompiler.java.patch

@@ -44,6 +44,16 @@
          for (Entry<RenderType, BufferBuilder> entry : map.entrySet()) {
              RenderType rendertype1 = entry.getKey();
              MeshData meshdata = entry.getValue().build();
+@@ -105,7 +_,8 @@
+         BufferBuilder bufferbuilder = p_350651_.get(p_350494_);
+         if (bufferbuilder == null) {
+             ByteBufferBuilder bytebufferbuilder = p_350965_.buffer(p_350494_);
+-            bufferbuilder = new BufferBuilder(bytebufferbuilder, VertexFormat.Mode.QUADS, DefaultVertexFormat.BLOCK);
++            //Neo: build BufferBuilder based on RenderType's format and mode
++            bufferbuilder = new BufferBuilder(bytebufferbuilder, p_350494_.mode, p_350494_.format);
+             p_350651_.put(p_350494_, bufferbuilder);
+         }
+
 @@ -115,9 +_,10 @@
      private <E extends BlockEntity> void handleBlockEntity(SectionCompiler.Results p_350754_, E p_350386_) {
          BlockEntityRenderer<E> blockentityrenderer = this.blockEntityRenderer.getRenderer(p_350386_);

src/main/java/net/neoforged/neoforge/client/ClientHooks.java

@@ -131,6 +131,10 @@
 import net.neoforged.fml.ModLoader;
 import net.neoforged.fml.common.EventBusSubscriber;
 import net.neoforged.fml.common.asm.enumextension.ExtensionInfo;
+import net.neoforged.neoforge.client.buffer.VanillaBufferDefinitions;
+import net.neoforged.neoforge.client.buffer.chunk.ChunkBufferDefinitionManager;
+import net.neoforged.neoforge.client.buffer.chunk.IChunkBufferCallback;
+import net.neoforged.neoforge.client.buffer.chunk.ISectionLayerRenderer;
 import net.neoforged.neoforge.client.entity.animation.json.AnimationTypeManager;
 import net.neoforged.neoforge.client.event.AddSectionGeometryEvent;
 import net.neoforged.neoforge.client.event.CalculateDetachedCameraDistanceEvent;
@@ -273,11 +277,32 @@ public static boolean onDrawHighlight(LevelRenderer context, Camera camera, Bloc
     public static void dispatchRenderStage(RenderLevelStageEvent.Stage stage, LevelRenderer levelRenderer, @Nullable PoseStack poseStack, Matrix4f modelViewMatrix, Matrix4f projectionMatrix, int renderTick, Camera camera, Frustum frustum) {
         var mc = Minecraft.getInstance();
         var profiler = Profiler.get();
+
         profiler.push(stage.toString());
         NeoForge.EVENT_BUS.post(new RenderLevelStageEvent(stage, levelRenderer, poseStack, modelViewMatrix, projectionMatrix, renderTick, mc.getDeltaTracker(), camera, frustum));
+        dispatchCustomChunkBuffers(stage, levelRenderer, modelViewMatrix, projectionMatrix, camera.getPosition().toVector3f());
         profiler.pop();
     }
 
+    public static void dispatchCustomChunkBuffers(RenderLevelStageEvent.Stage stage, LevelRenderer levelRenderer, Matrix4f modelViewMatrix, Matrix4f projectionMatrix, Vector3f position) {
+        ChunkBufferDefinitionManager.getChunkBufferDefinitions(stage).forEach(entry -> {
+            RenderType renderType = VanillaBufferDefinitions.bakeVanillaRenderType(entry.bufferDefinition());
+            IChunkBufferCallback callback = entry.callback();
+            ISectionLayerRenderer sectionLayerRenderer = ISectionLayerRenderer.vanilla(renderType, levelRenderer);
+
+            callback.onRenderChunkBuffer(
+                    sectionLayerRenderer,
+                    levelRenderer,
+                    entry.bufferDefinition(),
+                    position.x,
+                    position.y,
+                    position.z,
+                    modelViewMatrix,
+                    projectionMatrix);
+            levelRenderer.renderBuffers.bufferSource().endBatch(renderType);
+        });
+    }
+
     public static void dispatchRenderStage(RenderType renderType, LevelRenderer levelRenderer, Matrix4f modelViewMatrix, Matrix4f projectionMatrix, int renderTick, Camera camera, Frustum frustum) {
         RenderLevelStageEvent.Stage stage = RenderLevelStageEvent.Stage.fromRenderType(renderType);
         if (stage != null)

src/main/java/net/neoforged/neoforge/client/buffer/DefaultBufferDefinition.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforge.client.buffer;
+
+import com.google.common.collect.ImmutableMap;
+import java.util.Optional;
+import net.minecraft.resources.ResourceLocation;
+import net.neoforged.neoforge.client.buffer.param.BufferDefinitionParamTypeManager;
+import net.neoforged.neoforge.client.buffer.param.IBufferDefinitionParam;
+import net.neoforged.neoforge.client.buffer.param.IBufferDefinitionParamType;
+
+/**
+ * The default implementation of {@link IBufferDefinition}. Stores params in an {@link ImmutableMap}
+ */
+public class DefaultBufferDefinition implements IBufferDefinition {
+    private final ImmutableMap<IBufferDefinitionParamType<?, ?>, IBufferDefinitionParam<?>> params;
+
+    public DefaultBufferDefinition(ImmutableMap<IBufferDefinitionParamType<?, ?>, IBufferDefinitionParam<?>> params) {
+        this.params = params;
+    }
+
+    public DefaultBufferDefinition() {
+        this.params = ImmutableMap.of();
+    }
+
+    @Override
+    public boolean hasParam(IBufferDefinitionParamType<?, ?> param) {
+        return params.containsKey(param);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T, P extends IBufferDefinitionParam<T>> Optional<T> getParam(IBufferDefinitionParamType<T, P> paramType) {
+        return Optional.ofNullable(params.get(paramType)).map(param -> (T) param.getValue());
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T, P extends IBufferDefinitionParam<T>> T getParamOrDefault(IBufferDefinitionParamType<T, P> type) {
+        return (T) params.getOrDefault(type, type.getDefaultValue()).getValue();
+    }
+
+    @Override
+    public ImmutableMap<IBufferDefinitionParamType<?, ?>, IBufferDefinitionParam<?>> getParams() {
+        return params;
+    }
+
+    /**
+     * Create and returns the {@link IBufferDefinitionBuilder} implementation for {@link IBufferDefinition}
+     * 
+     * @return the builder created
+     */
+    public static IBufferDefinitionBuilder builder() {
+        return new Builder();
+    }
+
+    public static class Builder implements IBufferDefinitionBuilder {
+        private final ImmutableMap.Builder<IBufferDefinitionParamType<?, ?>, IBufferDefinitionParam<?>> params;
+
+        private Builder() {
+            this.params = ImmutableMap.builder();
+        }
+
+        @Override
+        public IBufferDefinitionBuilder withParam(IBufferDefinitionParamType<?, ?> type, IBufferDefinitionParam<?> param) {
+            params.put(type, param);
+            return this;
+        }
+
+        @Override
+        public IBufferDefinitionBuilder withParam(ResourceLocation resourceLocation, IBufferDefinitionParam<?> param) {
+            getParamType(resourceLocation).ifPresent(type -> params.put(type, param));
+            return this;
+        }
+
+        @Override
+        public IBufferDefinitionBuilder withParam(IBufferDefinitionParam<?> param) {
+            params.put(param.getType(), param);
+            return this;
+        }
+
+        @Override
+        public IBufferDefinition build() {
+            return new DefaultBufferDefinition(params.build());
+        }
+
+        private Optional<IBufferDefinitionParamType<?, ?>> getParamType(ResourceLocation resourceLocation) {
+            return Optional.ofNullable(BufferDefinitionParamTypeManager.getParamType(resourceLocation));
+        }
+    }
+}

src/main/java/net/neoforged/neoforge/client/buffer/IBufferDefinition.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforge.client.buffer;
+
+import com.google.common.collect.ImmutableMap;
+import java.util.Optional;
+import net.neoforged.neoforge.client.buffer.param.IBufferDefinitionParam;
+import net.neoforged.neoforge.client.buffer.param.IBufferDefinitionParamType;
+
+public interface IBufferDefinition {
+    boolean hasParam(IBufferDefinitionParamType<?, ?> param);
+
+    <T, P extends IBufferDefinitionParam<T>> Optional<T> getParam(IBufferDefinitionParamType<T, P> paramType);
+
+    <T, P extends IBufferDefinitionParam<T>> T getParamOrDefault(IBufferDefinitionParamType<T, P> type);
+
+    ImmutableMap<IBufferDefinitionParamType<?, ?>, IBufferDefinitionParam<?>> getParams();
+}

src/main/java/net/neoforged/neoforge/client/buffer/IBufferDefinitionBuilder.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforge.client.buffer;
+
+import net.minecraft.resources.ResourceLocation;
+import net.neoforged.neoforge.client.buffer.param.IBufferDefinitionParam;
+import net.neoforged.neoforge.client.buffer.param.IBufferDefinitionParamType;
+import net.neoforged.neoforge.client.buffer.param.general.IGeneralUsageParam;
+import net.neoforged.neoforge.client.event.RegisterBufferDefinitionParamTypeAliasesEvent;
+
+public interface IBufferDefinitionBuilder {
+    /**
+     * Add a {@link IBufferDefinitionParam} to the {@link IBufferDefinition} with a specified {@link IBufferDefinitionParamType}.
+     * Can be used for {@link IGeneralUsageParam}.
+     * 
+     * @param type  the param type
+     * @param param the param value
+     * @return the builder itself
+     */
+    IBufferDefinitionBuilder withParam(IBufferDefinitionParamType<?, ?> type, IBufferDefinitionParam<?> param);
+
+    /**
+     * Add a {@link IBufferDefinitionParam} to the {@link IBufferDefinition} with a param type described in a {@link ResourceLocation}.
+     * It can specify param type without accessing the {@link IBufferDefinitionParamType} instance. (e.g. provided by other mods)
+     * Generally used for {@link IGeneralUsageParam}.
+     * 
+     * @param resourceLocation the registered location of the param type
+     * @param param            the param value
+     * @return the builder itself
+     * @see RegisterBufferDefinitionParamTypeAliasesEvent
+     */
+    IBufferDefinitionBuilder withParam(ResourceLocation resourceLocation, IBufferDefinitionParam<?> param);
+
+    /**
+     * Add a {@link IBufferDefinitionParam} to the {@link IBufferDefinition} with {@link IBufferDefinitionParamType} automatically determined by {@link IBufferDefinitionParam#getType()}.
+     * <STRONG>CANNOT</STRONG> be used for {@link IGeneralUsageParam}.
+     * 
+     * @param param the param value
+     * @return the builder itself
+     * @see IGeneralUsageParam#getType()
+     */
+    IBufferDefinitionBuilder withParam(IBufferDefinitionParam<?> param);
+
+    /**
+     * Build the {@link IBufferDefinition} with params declared.
+     * 
+     * @return the built buffer definition
+     */
+    IBufferDefinition build();
+}