LYGIA Shader Library

Use:

srandomX(<vec2|vec3> x)

Check it on Github

#ifndef FNC_SRANDOM
#define FNC_SRANDOM

float srandom(in float x) {
  return -1. + 2. * fract(sin(x) * 43758.5453);
}

float srandom(in vec2 st) {
  return -1. + 2. * fract(sin(dot(st.xy, vec2(12.9898, 78.233))) * 43758.5453);
}

float srandom(in vec3 pos) {
  return -1. + 2. * fract(sin(dot(pos.xyz, vec3(70.9898, 78.233, 32.4355))) * 43758.5453123);
}

float srandom(in vec4 pos) {
    float dot_product = dot(pos, vec4(12.9898,78.233,45.164,94.673));
    return -1. + 2. * fract(sin(dot_product) * 43758.5453);
}

vec2 srandom2(in vec2 st) {
    const vec2 k = vec2(.3183099, .3678794);
    st = st * k + k.yx;
    return -1. + 2. * fract(16. * k * fract(st.x * st.y * (st.x + st.y)));
}

vec3 srandom3(in vec3 p) {
    p = 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 -1. + 2. * fract(sin(p) * 43758.5453123);
}

vec2 srandom2(in vec2 p, const in float tileLength) {
    p = mod(p, vec2(tileLength));
    return srandom2(p);
}

vec3 srandom3(in vec3 p, const in float tileLength) {
    p = mod(p, vec3(tileLength));
    return srandom3(p);
}

#endif

Use:

srandomX(<float2|float3> x)

Check it on Github

#ifndef FNC_SRANDOM
#define FNC_SRANDOM

float2 srandom2(in float2 st) {
    const float2 k = float2(.3183099, .3678794);
    st = st * k + k.yx;
    return -1. + 2. * frac(16. * k * frac(st.x * st.y * (st.x + st.y)));
}

float3 srandom3(in float3 p) {
    p = float3( dot(p, float3(127.1, 311.7, 74.7)),
            dot(p, float3(269.5, 183.3, 246.1)),
            dot(p, float3(113.5, 271.9, 124.6)));
    return -1. + 2. * frac(sin(p) * 43758.5453123);
}

#endif