noise

#define PI 3.14159265
float perlin(vec3 p){
	vec3 i = floor(p);
	vec4 a = dot(i, vec3(1.0, 57.0, 21.0)) + vec4(0.0, 57.0, 21.0, 78.0);
	vec3 f = cos((p - i) * PI) * (-0.5) + 0.5;
	a = mix(sin(cos(a) * a), sin(cos(1.0 + a) * (1.0 + a)), f.x);
	a.xy = mix(a.xz, a.yw, f.y);
	return mix(a.x, a.y, f.z);
}