103 lines
3.2 KiB
Plaintext
103 lines
3.2 KiB
Plaintext
// Put the following line to 0 or comment it to disable vignette weighting
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#define USE_VIGNETTE_WEIGHTING 1
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#pragma warning(disable : 3568)
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#pragma exclude_renderers gles gles3 d3d11_9x
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#include "Packages/com.unity.postprocessing/PostProcessing/Shaders/StdLib.hlsl"
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#include "Packages/com.unity.postprocessing/PostProcessing/Shaders/Colors.hlsl"
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#include "Packages/com.unity.postprocessing/PostProcessing/Shaders/Builtins/ExposureHistogram.hlsl"
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RWStructuredBuffer<uint> _HistogramBuffer;
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Texture2D<float4> _Source;
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SamplerState sampler_LinearClamp;
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CBUFFER_START(Params)
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float4 _ScaleOffsetRes; // x: scale, y: offset, z: width, w: height
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CBUFFER_END
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groupshared uint gs_histogram[HISTOGRAM_BINS];
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#pragma kernel KEyeHistogram
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#ifdef DISABLE_COMPUTE_SHADERS
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TRIVIAL_COMPUTE_KERNEL(KEyeHistogram)
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TRIVIAL_COMPUTE_KERNEL(KEyeHistogramClear)
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#else
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[numthreads(HISTOGRAM_THREAD_X, HISTOGRAM_THREAD_Y, 1)]
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void KEyeHistogram(uint2 dispatchThreadId : SV_DispatchThreadID, uint2 groupThreadId : SV_GroupThreadID)
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{
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const uint localThreadId = groupThreadId.y * HISTOGRAM_THREAD_X + groupThreadId.x;
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// Clears the shared memory
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#if HISTOGRAM_REDUCTION_ALT_PATH
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uint localThreadIdOff = localThreadId << 1u;
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if (localThreadIdOff < HISTOGRAM_BINS)
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{
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gs_histogram[localThreadIdOff ] = 0u;
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gs_histogram[localThreadIdOff + 1] = 0u;
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}
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#else
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if (localThreadId < HISTOGRAM_BINS)
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{
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gs_histogram[localThreadId] = 0u;
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}
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#endif
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float2 ipos = float2(dispatchThreadId) * 2.0;
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GroupMemoryBarrierWithGroupSync();
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// Gather local group histogram
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if (ipos.x < _ScaleOffsetRes.z && ipos.y < _ScaleOffsetRes.w)
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{
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uint weight = 1u;
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float2 sspos = ipos / _ScaleOffsetRes.zw;
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// Vignette weighting to put more focus on what's in the center of the screen
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#if USE_VIGNETTE_WEIGHTING
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{
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float2 d = abs(sspos - (0.5).xx);
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float vfactor = saturate(1.0 - dot(d, d));
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vfactor *= vfactor;
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weight = (uint)(64.0 * vfactor);
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}
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#endif
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float3 color = _Source.SampleLevel(sampler_LinearClamp, sspos, 0.0).xyz; // Bilinear downsample 2x
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float luminance = Luminance(color);
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float logLuminance = GetHistogramBinFromLuminance(luminance, _ScaleOffsetRes.xy);
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uint idx = (uint)(logLuminance * (HISTOGRAM_BINS - 1u));
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InterlockedAdd(gs_histogram[idx], weight);
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}
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GroupMemoryBarrierWithGroupSync();
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// Merge everything
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#if HISTOGRAM_REDUCTION_ALT_PATH
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if (localThreadIdOff < HISTOGRAM_BINS)
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{
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InterlockedAdd(_HistogramBuffer[localThreadIdOff ], gs_histogram[localThreadIdOff ]);
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InterlockedAdd(_HistogramBuffer[localThreadIdOff + 1], gs_histogram[localThreadIdOff + 1]);
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}
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#else
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if (localThreadId < HISTOGRAM_BINS)
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{
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InterlockedAdd(_HistogramBuffer[localThreadId], gs_histogram[localThreadId]);
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}
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#endif
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}
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#pragma kernel KEyeHistogramClear
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[numthreads(HISTOGRAM_THREAD_X, 1, 1)]
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void KEyeHistogramClear(uint dispatchThreadId : SV_DispatchThreadID)
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{
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if (dispatchThreadId < HISTOGRAM_BINS)
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_HistogramBuffer[dispatchThreadId] = 0u;
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}
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#endif // DISABLE_COMPUTE_SHADERS
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