98 lines
2.6 KiB
Plaintext
98 lines
2.6 KiB
Plaintext
Shader "Hidden/PostProcessing/Debug/Histogram"
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{
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HLSLINCLUDE
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#pragma exclude_renderers gles gles3 d3d11_9x
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#pragma target 4.5
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#include "Packages/com.unity.postprocessing/PostProcessing/Shaders/StdLib.hlsl"
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#if SHADER_API_GLES3
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#define HISTOGRAM_BINS 128
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#else
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#define HISTOGRAM_BINS 256
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#endif
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struct VaryingsHistogram
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{
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float4 vertex : SV_POSITION;
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float2 texcoord : TEXCOORD0;
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float maxValue : TEXCOORD1;
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};
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StructuredBuffer<uint> _HistogramBuffer;
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float2 _Params; // x: width, y: height
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float FindMaxHistogramValue()
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{
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uint maxValue = 0u;
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UNITY_UNROLL
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for (uint i = 0; i < HISTOGRAM_BINS; i++)
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{
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uint h = _HistogramBuffer[i];
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maxValue = max(maxValue, h);
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}
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return float(maxValue);
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}
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VaryingsHistogram Vert(AttributesDefault v)
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{
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VaryingsHistogram o;
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o.vertex = float4(v.vertex.xy, 0.0, 1.0);
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o.texcoord = TransformTriangleVertexToUV(v.vertex.xy);
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#if UNITY_UV_STARTS_AT_TOP
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o.texcoord = o.texcoord * float2(1.0, -1.0) + float2(0.0, 1.0);
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#endif
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#if SHADER_API_GLES3 // No texture loopup in VS on GLES3/Android
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o.maxValue = 0;
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#else
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o.maxValue = _Params.y / FindMaxHistogramValue();
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#endif
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return o;
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}
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float4 Frag(VaryingsHistogram i) : SV_Target
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{
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#if SHADER_API_GLES3
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float maxValue = _Params.y / FindMaxHistogramValue();
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#else
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float maxValue = i.maxValue;
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#endif
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const float kBinsMinusOne = HISTOGRAM_BINS - 1.0;
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float remapI = i.texcoord.x * kBinsMinusOne;
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uint index = floor(remapI);
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float delta = frac(remapI);
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float v1 = float(_HistogramBuffer[index]) * maxValue;
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float v2 = float(_HistogramBuffer[min(index + 1, kBinsMinusOne)]) * maxValue;
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float h = v1 * (1.0 - delta) + v2 * delta;
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uint y = (uint)round(i.texcoord.y * _Params.y);
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float3 color = (0.0).xxx;
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float fill = step(y, h);
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color = lerp(color, (1.0).xxx, fill);
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return float4(color, 1.0);
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}
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ENDHLSL
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SubShader
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{
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Cull Off ZWrite Off ZTest Always
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Pass
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{
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HLSLPROGRAM
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#pragma vertex Vert
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#pragma fragment Frag
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ENDHLSL
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}
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}
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}
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