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Contents
/**
* Converts an RGB color to CIE Yxy.
* <p>The conversion is described in
* <a href="http://content.gpwiki.org/index.php/D3DBook:High-Dynamic_Range_Rendering#Luminance_Transform">Luminance Transform</a>
* </p>
*
* @name czm_RGBToXYZ
* @glslFunction
*
* @param {vec3} rgb The color in RGB.
*
* @returns {vec3} The color in CIE Yxy.
*
* @example
* vec3 xyz = czm_RGBToXYZ(rgb);
* xyz.x = max(xyz.x - luminanceThreshold, 0.0);
* rgb = czm_XYZToRGB(xyz);
*/
vec3 czm_RGBToXYZ(vec3 rgb)
{
const mat3 RGB2XYZ = mat3(0.4124, 0.2126, 0.0193,
0.3576, 0.7152, 0.1192,
0.1805, 0.0722, 0.9505);
vec3 xyz = RGB2XYZ * rgb;
vec3 Yxy;
Yxy.r = xyz.g;
float temp = dot(vec3(1.0), xyz);
Yxy.gb = xyz.rg / temp;
return Yxy;
}
Version data entries
8 entries across 8 versions & 1 rubygems