104 lines
2.5 KiB
HLSL
104 lines
2.5 KiB
HLSL
fixed4 _ChromaKeyColor;
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float _ChromaKeySimilarity;
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float _ChromaKeySmoothRange;
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float _ChromaKeySpillRange;
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// https://en.wikipedia.org/wiki/YUV
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float3 RGB2YUV(float3 rgb)
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{
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float r = rgb.x;
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float g = rgb.y;
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float b = rgb.z;
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float y = 0.2126 * r + 0.7152 * g + 0.0722 * b;
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float u = -0.09991 * r - 0.33609 * g + 0.436 * b;
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float v = 0.615 * r - 0.55861 * g - 0.05639 * b;
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return float3(y, u, v);
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}
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float3 YUV2RGB(float3 yuv)
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{
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float y = yuv.x;
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float u = yuv.y;
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float v = yuv.z;
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float r = y + 1.28033 * v;
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float g = y - 0.21482 * u - 0.38059 * v;
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float b = y + 2.12798 * u;
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return float3(r, g, b);
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}
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fixed4 GetCameraColor(float2 colorUV);
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float ColorDistance_YUV_YUV(float3 yuv1, float3 yuv2)
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{
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float dist = distance(yuv1.yz, yuv2.yz);
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// Increase the distance if the brightness of the first color is too high.
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// It fixed the error on the over exposure areas
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dist += saturate(yuv1.x - 0.9);
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return dist;
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}
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float ColorDistance_RGB_YUV(float3 rgb1, float3 yuv2)
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{
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float3 yuv1 = RGB2YUV(rgb1);
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return ColorDistance_YUV_YUV(yuv1, yuv2);
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}
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float ColorDistance_RGB_RGB(float3 rgb1, float3 rgb2)
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{
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float3 yuv1 = RGB2YUV(rgb1);
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float3 yuv2 = RGB2YUV(rgb2);
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return ColorDistance_YUV_YUV(yuv1, yuv2);
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}
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float RGB2Gray(float3 rgb)
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{
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float r = rgb.x;
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float g = rgb.y;
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float b = rgb.z;
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float y = 0.2126 * r + 0.7152 * g + 0.0722 * b;
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return y;
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}
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float GetAlphaFromDistance(float dist)
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{
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float result = smoothstep(_ChromaKeySimilarity, _ChromaKeySimilarity + _ChromaKeySmoothRange, dist);
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result = result * result;
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return result;
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}
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float GetSpillFromDistance(float dist)
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{
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float result = smoothstep(_ChromaKeySimilarity, _ChromaKeySimilarity + _ChromaKeySpillRange, dist);
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result = result * result * result;
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return result;
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}
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float4 GetColorAfterChromaKey(float2 UV, float2 deltaUV, float step)
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{
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float3 chromaColor = _ChromaKeyColor.rgb;
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float3 chromaYUV = RGB2YUV(chromaColor);
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float dist = 0.0;
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const int samples = 3;
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float offset = ((float)samples - 1.0) / 2.0;
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for (int i = 0; i < samples; ++i)
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{
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for (int j = 0; j < samples; ++j)
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{
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fixed4 color = GetCameraColor(UV + float2((float)i - offset, (float)j - offset) * deltaUV * step);
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float d = ColorDistance_RGB_YUV(color, chromaYUV);
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dist += d;
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}
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}
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dist /= (samples * samples);
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fixed4 centerColor = GetCameraColor(UV);
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float alpha = GetAlphaFromDistance(dist);
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float spill = GetSpillFromDistance(dist);
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float gray = RGB2Gray(centerColor.rgb);
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float4 outColor;
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outColor.rgb = lerp(float3(gray, gray, gray), centerColor.rgb, spill);
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outColor.a = alpha;
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return outColor;
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}
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