Staging before meshlet linearization

res/shaders/BasePass.slang

@@ -12,8 +12,14 @@ struct LightCullingData
 layout(set=5)
 ParameterBlock<LightCullingData> pLightCullingData;
 
+struct FragmentOutput
+{
+    float4 color : SV_Target0;
+    uint meshletId : SV_Target1;
+};
+
 [shader("pixel")]
-float4 fragmentMain(in FragmentParameter params) : SV_Target
+FragmentOutput fragmentMain(in FragmentParameter params)
 {
     LightingParameter lightingParams = params.getLightingParameter();
     MaterialParameter materialParams = params.getMaterialParameter();
@@ -35,5 +41,8 @@ float4 fragmentMain(in FragmentParameter params) : SV_Target
     // gamma correction
     result = result / (result + float3(1.0));
     result = pow(result, float3(1.0/2.2));
-    return float4(result, 1.0f);
+    FragmentOutput output;
+    output.color = float4(result, 1.0f);
+    output.meshletId = params.meshletId;
+    return output;
 }

res/shaders/MeshletPass.slang

@@ -94,7 +94,8 @@ void meshMain(
 		uint v = min(i, m.vertexCount - 1);
 		{
 			uint vertexIndex = pScene.vertexIndices[m.vertexOffset + v];
-			VertexAttributes attr = pVertexData.getAttributes(md.indicesOffset + vertexIndex);
+			VertexAttributes attr = pVertexData.getAttributes(m.indicesOffset + vertexIndex);
+			attr.meshletId = -1;
 			vertices[v] = attr.getParameter(inst.transformMatrix);
 			//vertices[v].vertexColor = m.color;
 		}

res/shaders/StaticMeshletPass.slang

@@ -9,6 +9,12 @@ struct PrimitiveAttributes
 	uint cull: SV_CullPrimitive;
 };
 
+struct CulledMeshletList
+{
+	StructuredBuffer<uint> meshletIndices;
+};
+ParameterBlock<CulledMeshletList> pCullingList;
+
 [numthreads(MESH_GROUP_SIZE, 1, 1)]
 [outputtopology("triangle")]
 [shader("mesh")]
@@ -18,7 +24,8 @@ void meshMain(
 	out vertices FragmentParameter vertices[MAX_VERTICES], 
 	out indices uint3 indices[MAX_PRIMITIVES]
 ){
-	MeshletDescription m = pScene.meshletInfos[groupID];
+	uint meshletIndex = pCullingList.meshletIndices[groupID];
+	MeshletDescription m = pScene.meshletInfos[meshletIndex];
 	SetMeshOutputCounts(m.vertexCount, m.primitiveCount);
 	
 	for(uint i = threadID; i < MAX_PRIMITIVES; i += MESH_GROUP_SIZE)
@@ -36,7 +43,8 @@ void meshMain(
 		uint v = min(i, m.vertexCount - 1);
 		{
 			uint vertexIndex = pScene.vertexIndices[m.vertexOffset + v];
-			VertexAttributes attr = pVertexData.getAttributes(md.indicesOffset + vertexIndex);
+			VertexAttributes attr = pVertexData.getAttributes(m.indicesOffset + vertexIndex);
+			attr.meshletId = meshletIndex;
 			vertices[v] = attr.getParameter(float4x4(1.0));
 		}
 	}

res/shaders/lib/MaterialParameter.slang

@@ -25,6 +25,7 @@ struct FragmentParameter
 	float3 biTangent_WS : TANGENT1;
 	float3 position_WS : POSITION2;
 	float3 vertexColor : COLOR0;
+	uint meshletId : POSITION3;
 	float2 texCoords[MAX_TEXCOORDS] : TEXCOORD0;
 	MaterialParameter getMaterialParameter()
 	{
@@ -55,6 +56,7 @@ struct VertexAttributes
 	float3 tangent_MS;
 	float3 biTangent_MS;
 	float3 vertexColor;
+	uint meshletId;
 	float2 texCoords[MAX_TEXCOORDS];
 	FragmentParameter getParameter(float4x4 transformMatrix)
 	{
@@ -73,6 +75,7 @@ struct VertexAttributes
 		result.position_WS = worldPos.xyz;
 		result.position_CS = clipPos;
 		result.vertexColor = vertexColor;
+		result.meshletId = meshletId;
 		for(uint i = 0; i < MAX_TEXCOORDS; ++i)
 		{
 			result.texCoords[i] = texCoords[i];

res/shaders/lib/Scene.slang

@@ -8,7 +8,7 @@ struct MeshletDescription
 	uint32_t vertexOffset;
 	uint32_t primitiveOffset;
 	float3 color;
-	float pad;
+	uint32_t indicesOffset;
 };
 
 struct MeshData
@@ -18,8 +18,6 @@ struct MeshData
 	uint32_t meshletOffset;
 	uint32_t firstIndex;
 	uint32_t numIndices;
-	uint32_t indicesOffset;
-	uint32_t pad0[3];
 };
 
 static const uint MAX_VERTICES = 256;