30 lines
970 B
GLSL
30 lines
970 B
GLSL
// Simple "dithering" effect
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// (c) moni-dz (https://github.com/moni-dz)
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// CC BY-NC-SA 4.0 (https://creativecommons.org/licenses/by-nc-sa/4.0/)
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// Packed bayer pattern using bit manipulation
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const float bayerPattern[4] = float[4](
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0x0514, // Encoding 0,8,2,10
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0xC4E6, // Encoding 12,4,14,6
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0x3B19, // Encoding 3,11,1,9
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0xF7D5 // Encoding 15,7,13,5
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);
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float getBayerFromPacked(int x, int y) {
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int idx = (x & 3) + ((y & 3) << 2);
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return float((int(bayerPattern[y & 3]) >> ((x & 3) << 2)) & 0xF) * (1.0 / 16.0);
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}
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#define LEVELS 2.0 // Available color steps per channel
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#define INV_LEVELS (1.0 / LEVELS)
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void mainImage(out vec4 fragColor, in vec2 fragCoord)
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{
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vec2 uv = fragCoord * (1.0 / iResolution.xy);
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vec3 color = texture(iChannel0, uv).rgb;
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float threshold = getBayerFromPacked(int(fragCoord.x), int(fragCoord.y));
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vec3 dithered = floor(color * LEVELS + threshold) * INV_LEVELS;
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fragColor = vec4(dithered, 1.0);
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}
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