PRNG - Permuted Congruential Generator (pcg)

Based on https://www.jcgt.org/published/0009/03/02/ , PCG kind of Random Functions and by extension PCG3d, have a good balance between quality of the randomness and speed of execution, which makes a good choice Random Functions for shaders.

code:pcg3d.glsl

uvec3 pcg3d(uvec3 v) {

v = v * 1664525u + 1013904223u;

v.x += v.y * v.z;

v.y += v.z * v.x;

v.z += v.x * v.y;

v ^= v >> 16u;

v.x += v.y * v.z;

v.y += v.z * v.x;

v.z += v.x * v.y;

return v;

}

vec3 pcg3df(vec3 v) {

uvec3 r = pcg3d(floatBitsToUint(v));

return vec3(r) / float(UINT_MAX); // UINT_MAX = 0xFFFFFFFFu or -1u

}

code:other.glsl

vec3 hash3d(vec3 p){

uvec3 q= floatBitsToUint(p);

q = ((q>>16u)^q.yzx)*1111111111u;

return vec3(q)/float(-1U);

}