dbf-udg
view sdr/dither.p.glsl @ 2:c45c7a1f7d9d
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| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Wed, 09 Jan 2013 02:37:05 +0200 |
| parents | 2d27bfd21fc5 |
| children | 403ec1be3a1a |
line source
1 uniform sampler2D framebuf, dither_tex;
2 uniform int dither_levels, dither_size;
4 void main()
5 {
6 float levels = float(dither_levels);
8 vec4 pixel = texture2D(framebuf, gl_TexCoord[0].xy);
9 float lum = dot(pixel.xyz, vec3(0.2126, 0.7152, 0.0722));
10 // gamma correct luminance?
11 //lum = pow(lum, 1.0 / 2.2);
12 float coord_shift = floor(lum * levels) / levels;
14 vec2 dsz2 = vec2(float(dither_size), float(dither_size));
16 vec2 coord = mod(gl_FragCoord.xy, dsz2) / float(dither_size);
17 coord.y = coord.y / levels + coord_shift;
18 float val = texture2D(dither_tex, coord).x;
20 const vec3 dark_col = vec3(0.043, 0.286, 0.337);
21 const vec3 bright_col = vec3(0.965, 0.778, 0.555);
23 gl_FragColor = vec4(mix(dark_col, bright_col, val), 1.0);
24 }