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change HSV/RGB conversion to fast, branchless version

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hizzlekizzle 2016-11-11 10:15:39 -06:00 • committed by GitHub
parent 3ca09c1169
commit b421752001
1 changed files with 17 additions and 14 deletions
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31
misc/colorspace-tools.h
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@ -163,20 +163,23 @@ vec3 RGBtoHCV(vec3 RGB)
return vec3(H, C, Q.x);
}
vec3 RGBtoHSV(vec3 RGB)
{
vec3 HCV = RGBtoHCV(RGB);
float S = HCV.y / (HCV.z + 1e-10);
return vec3(HCV.x, S, HCV.z);
}
// Converting HSV to RGB
vec3 HSVtoRGB(vec3 HSV)
{
vec3 RGB = HUEtoRGB(HSV.x);
return ((RGB - 1.0) * HSV.y + 1.0) * HSV.z;
}
vec3 RGBtoHSV(vec3 c)
{
vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
vec4 p = c.g < c.b ? vec4(c.bg, K.wz) : vec4(c.gb, K.xy);
vec4 q = c.r < p.x ? vec4(p.xyw, c.r) : vec4(c.r, p.yzx);
float d = q.x - min(q.w, q.y);
float e = 1.0e-10;
return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
}
vec3 HSVtoRGB(vec3 c)
{
vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}
// conversion from NTSC RGB Reference White D65 ( color space used by NA/Japan TV's ) to XYZ
vec3 NTSC(vec3 c)