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November 14, 2015 09:39
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hsv rgb conversion glsl shader
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| // because http://lolengine.net/blog/2013/07/27/rgb-to-hsv-in-glsl is often down | |
| vec3 rgb2hsv(vec3 c) | |
| { | |
| vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0); | |
| vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g)); | |
| vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r)); | |
| 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 hsv2rgb(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); | |
| } | |
| /* | |
| // color shift | |
| vec3 hsv = rgb2hsv(fragColor.rgb); | |
| hsv.x = fract(hsv.x + iMouse.x / iResolution.x); | |
| fragColor.rgb = hsv2rgb(hsv); | |
| */ |
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