55 lines
2.0 KiB
Plaintext
55 lines
2.0 KiB
Plaintext
static const float LUT_SIZE = 33.0;
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static const float LUT_LAST_INDEX = 32.0;
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float3 sampleLutCell(float3 index)
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{
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float r = floor(index.r + 0.5);
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float g = floor(index.g + 0.5);
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float b = floor(index.b + 0.5);
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float atlasWidth = LUT_SIZE * LUT_SIZE;
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float2 lutUv;
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lutUv.x = (r + b * LUT_SIZE + 0.5) / atlasWidth;
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lutUv.y = (g + 0.5) / LUT_SIZE;
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return lutTexture.Sample(lutUv).rgb;
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}
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float3 applyLut33(float3 color)
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{
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float3 lutCoord = saturate(color) * LUT_LAST_INDEX;
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float3 baseIndex = floor(lutCoord);
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float3 nextIndex = min(baseIndex + 1.0, LUT_LAST_INDEX);
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float3 blend = lutCoord - baseIndex;
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float3 c000 = sampleLutCell(float3(baseIndex.r, baseIndex.g, baseIndex.b));
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float3 c100 = sampleLutCell(float3(nextIndex.r, baseIndex.g, baseIndex.b));
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float3 c010 = sampleLutCell(float3(baseIndex.r, nextIndex.g, baseIndex.b));
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float3 c110 = sampleLutCell(float3(nextIndex.r, nextIndex.g, baseIndex.b));
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float3 c001 = sampleLutCell(float3(baseIndex.r, baseIndex.g, nextIndex.b));
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float3 c101 = sampleLutCell(float3(nextIndex.r, baseIndex.g, nextIndex.b));
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float3 c011 = sampleLutCell(float3(baseIndex.r, nextIndex.g, nextIndex.b));
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float3 c111 = sampleLutCell(float3(nextIndex.r, nextIndex.g, nextIndex.b));
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float3 c00 = lerp(c000, c100, blend.r);
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float3 c10 = lerp(c010, c110, blend.r);
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float3 c01 = lerp(c001, c101, blend.r);
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float3 c11 = lerp(c011, c111, blend.r);
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float3 c0 = lerp(c00, c10, blend.g);
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float3 c1 = lerp(c01, c11, blend.g);
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return lerp(c0, c1, blend.b);
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}
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float4 shadeVideo(ShaderContext context)
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{
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float4 source = context.sourceColor;
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float3 inputColor = source.rgb * pow(2.0, preExposure);
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if (clampInput)
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inputColor = saturate(inputColor);
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float3 lutColor = applyLut33(inputColor);
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float3 graded = lerp(inputColor, lutColor, lutStrength);
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graded = (graded - 0.5) * postContrast + 0.5;
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return float4(saturate(graded), source.a);
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}
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