mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-03 23:15:23 +00:00
62 lines
1.7 KiB
GLSL
62 lines
1.7 KiB
GLSL
#ifdef GL_ES
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precision highp float;
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#endif
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uniform sampler2D u_tex0;
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uniform sampler2D u_tex1;
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uniform vec2 u_resolution;
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uniform vec2 u_mouse;
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uniform float u_time;
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// Author: Matt DesLauriers
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// https://github.com/mattdesl/glsl-lut/blob/master/index.glsl
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//
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#define LUT_NO_CLAMP
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#define LUT_FLIP_Y
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vec4 lookup(in vec4 textureColor, in sampler2D lookupTable) {
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#ifndef LUT_NO_CLAMP
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textureColor = clamp(textureColor, 0.0, 1.0);
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#endif
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float blueColor = textureColor.b * 63.0;
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vec2 quad1 = vec2(0.0);
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quad1.y = floor(floor(blueColor) / 8.0);
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quad1.x = floor(blueColor) - (quad1.y * 8.0);
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vec2 quad2 = vec2(0.0);
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quad2.y = floor(ceil(blueColor) / 8.0);
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quad2.x = ceil(blueColor) - (quad2.y * 8.0);
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vec2 texPos1 = vec2(0.0);
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texPos1.x = (quad1.x * 0.125) + 0.5/512.0 + ((0.125 - 1.0/512.0) * textureColor.r);
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texPos1.y = (quad1.y * 0.125) + 0.5/512.0 + ((0.125 - 1.0/512.0) * textureColor.g);
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#ifdef LUT_FLIP_Y
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texPos1.y = 1.0-texPos1.y;
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#endif
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vec2 texPos2 = vec2(0.0);
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texPos2.x = (quad2.x * 0.125) + 0.5/512.0 + ((0.125 - 1.0/512.0) * textureColor.r);
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texPos2.y = (quad2.y * 0.125) + 0.5/512.0 + ((0.125 - 1.0/512.0) * textureColor.g);
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#ifdef LUT_FLIP_Y
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texPos2.y = 1.0-texPos2.y;
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#endif
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vec4 newColor1 = texture2D(lookupTable, texPos1);
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vec4 newColor2 = texture2D(lookupTable, texPos2);
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vec4 newColor = mix(newColor1, newColor2, fract(blueColor));
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return newColor;
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}
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void main(){
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vec2 st = gl_FragCoord.st/u_resolution.xy;
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vec4 srcColor = texture2D(u_tex0, st);
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vec3 dstcolor = lookup(srcColor,u_tex1).rgb;
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gl_FragColor = vec4( dstcolor , 1.0);
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} |