35 lines
915 B
Plaintext
35 lines
915 B
Plaintext
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float3 HUEtoRGB(in float H)
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{
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float R = abs(H * 6 - 3) - 1;
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float G = 2 - abs(H * 6 - 2);
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float B = 2 - abs(H * 6 - 4);
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return saturate(float3(R,G,B));
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}
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float Epsilon = 1e-10;
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float3 RGBtoHCV(in float3 RGB)
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{
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// Based on work by Sam Hocevar and Emil Persson
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float4 P = (RGB.g < RGB.b) ? float4(RGB.bg, -1.0, 2.0/3.0) : float4(RGB.gb, 0.0, -1.0/3.0);
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float4 Q = (RGB.r < P.x) ? float4(P.xyw, RGB.r) : float4(RGB.r, P.yzx);
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float C = Q.x - min(Q.w, Q.y);
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float H = abs((Q.w - Q.y) / (6 * C + Epsilon) + Q.z);
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return float3(H, C, Q.x);
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}
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float3 RGBtoHSL(float3 RGB)
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{
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float3 HCV = RGBtoHCV(RGB);
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float L = HCV.z - HCV.y * 0.5;
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float S = HCV.y / (1 - abs(L * 2 - 1) + Epsilon);
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return float3(HCV.x, S, L);
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}
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float3 HSLtoRGB(float3 HSL)
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{
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float3 RGB = HUEtoRGB(HSL.x);
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float C = (1 - abs(2 * HSL.z - 1)) * HSL.y;
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return (RGB - 0.5) * C + HSL.z;
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}
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