Warning, /plasma/kwin/src/opengl/saturation.glsl is written in an unsupported language. File is not indexed.

 uniform float saturation;
 uniform vec3 primaryBrightness;
 
 vec4 adjustSaturation(vec4 color) {
     // this calculates the Y component of the XYZ color representation for the color,
     // which roughly corresponds to the brightness of the RGB tuple
     float Y = dot(color.rgb, primaryBrightness);
     return vec4(mix(vec3(Y), color.rgb, saturation), color.a);
 }