mirror of
https://github.com/curioustorvald/Terrarum.git
synced 2026-03-14 15:46:06 +09:00
61 lines
1.7 KiB
GLSL
61 lines
1.7 KiB
GLSL
varying vec4 v_color;
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varying vec2 v_texCoords;
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uniform sampler2D u_texture;
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uniform vec3 topColor;
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uniform vec3 bottomColor;
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// "steps" of R, G and B. Must be integer && equal or greater than 2
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uniform float rcount = 64.0; // it even works on 256.0!
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uniform float gcount = 64.0; // using 128: has less banding and most monitors are internally 6-bit
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uniform float bcount = 64.0;
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int bayer[9][9] = {
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{50,71,2,23,44,56,77,17,29},
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{72,12,33,45,66,6,18,39,60},
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{22,43,55,76,16,28,49,70,1},
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{53,65,5,26,38,59,80,11,32},
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{75,15,27,48,69,0,21,42,54},
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{25,37,58,79,10,31,52,64,4},
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{47,68,8,20,41,62,74,14,35},
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{78,9,30,51,63,3,24,36,57},
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{19,40,61,73,13,34,46,67,7}
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};
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float bayerSize = 9.0;
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float bayerDivider = bayerSize * bayerSize;
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vec4 nearestColour(vec4 incolor) {
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vec4 rgbaCounts = vec4(rcount, gcount, bcount, 1.0);
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vec4 color = incolor;
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color.r = floor((rgbaCounts.r - 1.0) * color.r + 0.5) / (rgbaCounts.r - 1.0);
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color.g = floor((rgbaCounts.g - 1.0) * color.g + 0.5) / (rgbaCounts.g - 1.0);
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color.b = floor((rgbaCounts.b - 1.0) * color.b + 0.5) / (rgbaCounts.b - 1.0);
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color.a = 1.0;
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return color;
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}
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void main(void) {
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float spread = 1.0 / (0.299 * (rcount - 1.0) + 0.587 * (gcount - 1.0) + 0.114 * (bcount - 1.0)); // this spread value is optimised one -- try your own values for various effects!
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float scale = v_texCoords.y;
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float inR = mix(bottomColor.r, topColor.r, scale);
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float inG = mix(bottomColor.g, topColor.g, scale);
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float inB = mix(bottomColor.b, topColor.b, scale);
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vec4 inColor = vec4(inR, inG, inB, 1.0);
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vec2 entry = mod(gl_FragCoord.xy, vec2(bayerSize, bayerSize));
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gl_FragColor = nearestColour(inColor + spread * (bayer[int(entry.y)][int(entry.x)] / bayerDivider - 0.5));
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} |