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@lhog
Last active Dec 3, 2021
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Some GLSL Random and Noise functions
const float M_PI = 3.1415926535897932384626433832795;
float rand(float p)
{
return fract(sin(p) * 43758.5453123);
}
/*
float rand(vec2 p)
{
return fract(sin(dot(p, vec2(12.9898, 4.1414))) * 43758.5453);
}
*/
//sugested replacement
float rand(vec2 co)
{
float a = 12.9898;
float b = 78.233;
float c = 43758.5453;
float dt = dot(co.xy ,vec2(a,b));
float sn = mod(dt, M_PI);
return fract(sin(sn) * c);
}
vec3 rand3(vec3 p)
{
vec3 q = vec3(
dot(p, vec3(127.1, 311.7, 74.7)),
dot(p, vec3(269.5, 183.3, 246.1)),
dot(p, vec3(113.5, 271.9, 124.6))
);
return fract(sin(q) * 43758.5453123);
}
vec3 rand3(vec2 p)
{
vec3 q = vec3(
dot(p, vec2(127.1, 311.7)),
dot(p, vec2(269.5, 183.3)),
dot(p, vec2(419.2, 371.9))
);
return fract(sin(q) * 43758.5453);
}
float noise(float p)
{
float fl = floor(p);
float fc = fract(p);
return mix(rand(fl), rand(fl + 1.0), fc);
}
float noise(vec2 n)
{
const vec2 d = vec2(0.0, 1.0);
vec2 b = floor(n), f = smoothstep(vec2(0.0), vec2(1.0), fract(n));
return mix(mix(rand(b), rand(b + d.yx), f.x), mix(rand(b + d.xy), rand(b + d.yy), f.x), f.y);
}
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