lib-random.glsl

Public Functions: getBlueNoiseThreshold getBlueNoiseThresholdTemporal fibonacci1D fibonacci2D fibonacci2DDitheredTemporal

Import from library

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import lib-defines.glsl
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import lib-defines.glsl

A 2D blue noise texture containing scalar values

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//: param auto texture_blue_noise
 uniform sampler2D texture_blue_noise;
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//: param auto texture_blue_noise
 uniform sampler2D texture_blue_noise;

Blue noise texture resolution

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const ivec2 texture_blue_noise_size = ivec2(256);
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const ivec2 texture_blue_noise_size = ivec2(256);

Current frame random seed

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//: param auto random_seed
 uniform int alg_random_seed;
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//: param auto random_seed
 uniform int alg_random_seed;

Get an uniform random value based on pixel coordinates.

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float getBlueNoiseThreshold()
 {
   return texture(texture_blue_noise, gl_FragCoord.xy / vec2(texture_blue_noise_size)).x + 0.5 / 65536.0;
 }
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float getBlueNoiseThreshold()
 {
   return texture(texture_blue_noise, gl_FragCoord.xy / vec2(texture_blue_noise_size)).x + 0.5 / 65536.0;
 }

Get an uniform random value based on pixel coordinates and frame id.

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float getBlueNoiseThresholdTemporal()
 {
   return fract(getBlueNoiseThreshold() + M_GOLDEN_RATIO * alg_random_seed);
 }
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float getBlueNoiseThresholdTemporal()
 {
   return fract(getBlueNoiseThreshold() + M_GOLDEN_RATIO * alg_random_seed);
 }

Return the ith number from fibonacci sequence.

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float fibonacci1D(int i)
 {
   return fract((float(i) + 1.0) * M_GOLDEN_RATIO);
 }
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float fibonacci1D(int i)
 {
   return fract((float(i) + 1.0) * M_GOLDEN_RATIO);
 }

Return the ith couple from the fibonacci sequence. nbSample is required to get an uniform distribution.

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vec2 fibonacci2D(int i, int nbSamples)
 {
   return vec2(
     (float(i)+0.5) / float(nbSamples),
     fibonacci1D(i)
   );
 }
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vec2 fibonacci2D(int i, int nbSamples)
 {
   return vec2(
     (float(i)+0.5) / float(nbSamples),
     fibonacci1D(i)
   );
 }

Return the ith couple from the fibonacci sequence. nbSample is required to get an uniform distribution. This version has a per frame and per pixel pseudo-random rotation applied.

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vec2 fibonacci2DDitheredTemporal(int i, int nbSamples)
 {
   vec2 s = fibonacci2D(i, nbSamples);
   s.x += getBlueNoiseThresholdTemporal();
   return s;
 }
 
 
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vec2 fibonacci2DDitheredTemporal(int i, int nbSamples)
 {
   vec2 s = fibonacci2D(i, nbSamples);
   s.x += getBlueNoiseThresholdTemporal();
   return s;
 }
 
 

Last updated 10/3/2024

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