annotate sdr/dither.p.glsl @ 11:5f99c4c7a9fe
now it looks pretty much ok
author |
John Tsiombikas <nuclear@member.fsf.org> |
date |
Wed, 20 Feb 2013 04:55:03 +0200 |
parents |
403ec1be3a1a |
children |
1abbed71e9c9 |
rev |
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1 uniform sampler2D framebuf, dither_tex;
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2 uniform int dither_levels, dither_size;
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3
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4 uniform float tfadein;
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5
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6 vec4 fetch_pixel(vec2 texcoord)
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7 {
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8 float x = step(0.5, mod(texcoord.y, 0.5) / 0.5);
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9 float offs = mix(1.0 - tfadein, tfadein - 1.0, x);
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10 vec2 tc = texcoord + vec2(offs, 0.0);
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11
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12 return (1.0 - step(1.0, tc.x)) * step(0.0, tc.x) * texture2D(framebuf, tc);
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13 }
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14
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15 void main()
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16 {
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17 float levels = float(dither_levels);
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18
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19 //vec4 pixel = texture2D(framebuf, gl_TexCoord[0].xy);
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20 vec4 pixel = fetch_pixel(gl_TexCoord[0].xy);
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21 float lum = dot(pixel.xyz, vec3(0.2126, 0.7152, 0.0722));
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22 float coord_shift = floor(lum * levels) / levels;
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23
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24 vec2 dsz2 = vec2(float(dither_size), float(dither_size));
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25
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26 vec2 coord = mod(gl_FragCoord.xy, dsz2) / float(dither_size);
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27 coord.y = coord.y / levels + coord_shift;
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28 float val = texture2D(dither_tex, coord).x;
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29
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30 const vec3 dark_col = vec3(0.043, 0.286, 0.337);
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31 const vec3 bright_col = vec3(0.965, 0.778, 0.555);
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32
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33 gl_FragColor = vec4(mix(dark_col, bright_col, val), 1.0);
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34 }
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