55 lines
1.4 KiB
GLSL
55 lines
1.4 KiB
GLSL
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precision mediump float;
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varying vec2 v_texcoord;
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uniform sampler2D tex;
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uniform float noise;
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uniform float brightness;
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uniform float contrast;
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uniform float saturation;
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mat4 brightnessMatrix() {
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float b = brightness - 1.0;
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return mat4(1, 0, 0, 0,
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0, 1, 0, 0,
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0, 0, 1, 0,
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b, b, b, 1);
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}
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mat4 contrastMatrix() {
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float t = (1.0 - contrast) / 2.0;
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return mat4(contrast, 0, 0, 0,
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0, contrast, 0, 0,
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0, 0, contrast, 0,
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t, t, t, 1);
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}
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mat4 saturationMatrix() {
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vec3 luminance = vec3(0.3086, 0.6094, 0.0820);
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float oneMinusSat = 1.0 - saturation;
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vec3 red = vec3(luminance.x * oneMinusSat);
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red+= vec3(saturation, 0, 0);
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vec3 green = vec3(luminance.y * oneMinusSat);
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green += vec3(0, saturation, 0);
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vec3 blue = vec3(luminance.z * oneMinusSat);
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blue += vec3(0, 0, saturation);
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return mat4(red, 0,
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green, 0,
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blue, 0,
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0, 0, 0, 1);
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}
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// Fast generative noise function
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float hash(vec2 p) {
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return fract(sin(dot(p, vec2(12.9898, 78.233))) * 43758.5453);
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}
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void main() {
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vec4 color = texture2D(tex, v_texcoord);
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color *= brightnessMatrix() * contrastMatrix() * saturationMatrix();
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float noiseHash = hash(v_texcoord);
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float noiseAmount = (mod(noiseHash, 1.0) - 0.5);
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color.rgb += noiseAmount * noise;
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gl_FragColor = color;
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}
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