In overlay matte, use the luminance as a matte instead of each individual color compo...
[movit] / input.frag
1 uniform sampler2D PREFIX(tex);
2
3 vec4 FUNCNAME(vec2 tc) {
4         // OpenGL's origin is bottom-left, but most graphics software assumes
5         // a top-left origin. Thus, for inputs that come from the user,
6         // we flip the y coordinate.
7         tc.y = 1.0f - tc.y;
8
9         return texture2D(PREFIX(tex), tc);
10 }