Initial Commit

Assets/Scripts/DeltaHoone/Weather_System/Grass/Compute/GrassFrustrumCuller.compute

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+#pragma kernel CSCullIndividual
+#pragma kernel CSCullCell
+
+struct GrassElement {
+    float3 position;
+    float rotation;
+    float size;
+    float colorBlend;//0-1
+    };
+
+struct grassCell {
+    uint grassElementIndexes[512];//map to grass elements
+    };
+
+//struct grassOcclusionCell {
+//    uint grassCellIndex;
+//    uint visibleCellIndexes[2048];//Map to occlusion cells
+//    };
+
+//General
+uint grassCount;
+float2 distanceBounts;//Start, end
+Texture2D<float4> ditherTex;
+int ditherTexSizeX;
+float ditherSize;
+
+//Input
+StructuredBuffer<GrassElement> grassBuffer;
+
+//Frustrum culling
+float3 cameraPos;
+float4x3 cameraFrustumNormals;
+
+//settings
+int doOcclusion;
+
+//Cells
+uint grassCellCount;
+uint grassCellSize;
+StructuredBuffer<grassCell> grassCellBuffer;
+
+//Occlusion culling
+//StructuredBuffer<grassOcclusionCell> grassOcclusionBuffer;
+
+//Output
+AppendStructuredBuffer<uint> outGrassBuffer;
+AppendStructuredBuffer<uint> outCellIndexBuffer;
+
+bool Is3DDither (float dist, float2 pos) {
+    float distAmount = 1 - (dist-distanceBounts.x)/(distanceBounts.y-distanceBounts.x);//0-1
+    float2 relativePos = pos/ditherSize;
+    float2 positivePos = float2(relativePos.x*sign(relativePos.x),relativePos.y*sign(relativePos.y));
+    float2 repeatingPos = float2(fmod(positivePos.x,ditherTexSizeX),fmod(positivePos.y,ditherTexSizeX));
+    float dit = ditherTex[repeatingPos].x;
+    return distAmount - dit > 0;
+    }
+
+[numthreads(16,16,4)]
+void CSCullIndividual (uint index : SV_GroupIndex, uint3 group : SV_GroupID) {//This only does frustrum culling
+    //1. get index
+    uint realIndex = index + 1024 * group.x;//id.x + id.y group.x + id.z group.x * group.y
+
+    //2. index valid?
+    if(realIndex < grassCount) {
+        GrassElement data = grassBuffer[realIndex];
+        float3 pos = data.position;
+
+        float3 posFromCamera = pos - cameraPos;
+        float scale = data.size;
+
+        //3. frustrum culling
+        if( (dot(cameraFrustumNormals[0], posFromCamera) > -scale) &&
+            (dot(cameraFrustumNormals[1], posFromCamera) > -scale) &&
+            (dot(cameraFrustumNormals[2], posFromCamera) > -scale) &&
+            (dot(cameraFrustumNormals[3], posFromCamera) > -scale) ){
+            //3D dither culling (includes dist culling)
+            float dist = length(posFromCamera);
+            if(Is3DDither(dist,pos.xz)) {
+                outGrassBuffer.Append(realIndex);
+                }
+            }
+        }
+    }
+
+[numthreads(8,8,1)]
+void CSCullCell (uint index : SV_GroupIndex, uint3 group : SV_GroupID) {//This does frustrum and occlusion culling on cells
+    //1. get index
+    uint realIndex = index + 8*8*group.x;
+    //2. index valid?
+
+    if(realIndex < grassCellCount) {
+        //outGrassBuffer.Append(realIndex);
+        //outCellIndexBuffer.Append(realIndex);
+        grassCell cell = grassCellBuffer[realIndex];
+        
+        //for(int i=0;i<512;i++) {
+        //    int k = cell.grassElementIndexes[i];
+        //    if(k != 0)outGrassBuffer.Append(k);
+        //    }
+        
+        //Doing frustrum check with ranodom element from cell
+        float3 pos = grassBuffer[cell.grassElementIndexes[0]].position;
+        
+        float3 posFromCamera = pos - cameraPos;
+        float scale = grassCellSize;
+        
+        //3. frustrum culling
+        if( (dot(cameraFrustumNormals[0], posFromCamera) > -scale) &&
+            (dot(cameraFrustumNormals[1], posFromCamera) > -scale) &&
+            (dot(cameraFrustumNormals[2], posFromCamera) > -scale) &&
+            (dot(cameraFrustumNormals[3], posFromCamera) > -scale) ){
+
+            if(length(posFromCamera) <= distanceBounts.y) {//Dist check
+                if(doOcclusion == 1) {
+                    //TODO see if this chunk is visible from current chunk
+                    //TODO if yes then append chunk grass indexes
+                    }
+                else {
+                    outCellIndexBuffer.Append(realIndex);
+                    }
+                }
+            }
+        }
+    }
+
+//group -> thread
+//SV_GroupThreadID = current threads num.xyz
+//SV_GroupIndex = num.x * num.y * num.z;
+//SV_GroupID = current gorup indices
+
+
+/* This works for some reason
+[numthreads(8,8,8)]
+void Converter (uint callIndex : SV_GroupIndex, uint3 groupID : SV_GroupID) {
+    uint realIndex = groupID.x + groupID.y + groupID.z;
+
+    uint cellIndex = grassCellIndexBuffer[realIndex];
+
+    grassCell cell = grassCellBuffer[ cellIndex ];
+
+    int elementIndex = callIndex;//Correct
+    uint objIndex = cell.grassElementIndexes[elementIndex];
+    if(objIndex != 0) outGrassBuffer.Append(objIndex);
+    
+    }
+*/