turanszkij
50 lines
1.8 KiB
HLSL
50 lines
1.8 KiB
HLSL
#include "globals.hlsli"
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#include "cullingShaderHF.hlsli"
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// View space frustums for the grid cells.
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RWSTRUCTUREDBUFFER(out_Frustums, Frustum, UAVSLOT_TILEFRUSTUMS);
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[numthreads(BLOCK_SIZE, BLOCK_SIZE, 1)]
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void main(ComputeShaderInput IN)
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{
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// View space eye position is always at the origin.
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const float3 eyePos = float3(0, 0, 0);
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// Compute 4 points on the far clipping plane to use as the
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// frustum vertices.
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float4 screenSpace[4];
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// Top left point
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screenSpace[0] = float4(IN.dispatchThreadID.xy * BLOCK_SIZE, 1.0f, 1.0f);
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// Top right point
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screenSpace[1] = float4(float2(IN.dispatchThreadID.x + 1, IN.dispatchThreadID.y) * BLOCK_SIZE, 1.0f, 1.0f);
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// Bottom left point
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screenSpace[2] = float4(float2(IN.dispatchThreadID.x, IN.dispatchThreadID.y + 1) * BLOCK_SIZE, 1.0f, 1.0f);
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// Bottom right point
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screenSpace[3] = float4(float2(IN.dispatchThreadID.x + 1, IN.dispatchThreadID.y + 1) * BLOCK_SIZE, 1.0f, 1.0f);
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float3 viewSpace[4];
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// Now convert the screen space points to view space
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for (int i = 0; i < 4; i++)
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{
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viewSpace[i] = ScreenToView(screenSpace[i]).xyz;
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}
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// Now build the frustum planes from the view space points
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Frustum frustum;
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// Left plane
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frustum.planes[0] = ComputePlane(viewSpace[2], eyePos, viewSpace[0]);
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// Right plane
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frustum.planes[1] = ComputePlane(viewSpace[1], eyePos, viewSpace[3]);
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// Top plane
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frustum.planes[2] = ComputePlane(viewSpace[0], eyePos, viewSpace[1]);
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// Bottom plane
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frustum.planes[3] = ComputePlane(viewSpace[3], eyePos, viewSpace[2]);
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// Store the computed frustum in global memory (if our thread ID is in bounds of the grid).
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if (IN.dispatchThreadID.x < xDispatchParams_numThreads.x && IN.dispatchThreadID.y < xDispatchParams_numThreads.y)
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{
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uint index = IN.dispatchThreadID.x + (IN.dispatchThreadID.y * xDispatchParams_numThreads.x);
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out_Frustums[index] = frustum;
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}
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} |