/usr/share/psychtoolbox-3/PsychOpenGL/PsychGLSLShaders/RGB2GrayConversionShader.frag.txt is in psychtoolbox-3-common 3.0.11.20131230.dfsg1-1build1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | /* Shader for conversion of RGB textures into Grayscale textures.
* Uses standard formula for conversion:
* (w)2006 by Mario Kleiner. Licensed under MIT license.
*/
#extension GL_ARB_texture_rectangle : enable
const vec3 ColorToGrayWeights = vec3(0.3, 0.59, 0.11);
uniform sampler2DRect Image;
void main()
{
vec4 incolor = texture2DRect(Image, gl_TexCoord[0].st);
float luminance = dot(incolor.rgb, ColorToGrayWeights);
gl_FragColor.a = incolor.a;
gl_FragColor.rgb = vec3(luminance);
}
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