public static float valuenoise(vec2 v)
{
ivec2 i = (ivec2)v;
vec2 f = fract(v);
float a = rand(i),
b = rand(i + ivec2.unitx),
c = rand(i + ivec2.unity),
d = rand(i + ivec2.one);
vec2 u = f * f * (3f - f * 2f);
return(lerp(a, b, u.x) +
(c - a) * u.y * (1f - u.x) +
(d - b) * u.x * u.y);
}
public static float rand(ivec2 seed) => rand(seed.x, seed.y);
