float randomValue(inout uint rng_state) { rng_state = rng_state * 747796405 + 2891336453; uint result = ((rng_state >> ((rng_state >> 28) + 4)) ^ rng_state) * 277803737; result = (result >> 22) ^ result; return (result / 4294967295.0); } float randomValueNormalDistribution(inout uint rng_state) { float theta = 2.0 * 3.14159265359 * randomValue(rng_state); float rho = sqrt(-2.0 * log(randomValue(rng_state))); return (rho * cos(theta)); } vec3 randomDirection(inout uint rng_state) { float x = randomValueNormalDistribution(rng_state); float y = randomValueNormalDistribution(rng_state); float z = randomValueNormalDistribution(rng_state); return normalize(vec3(x, y, z)); } vec3 randomHemisphereDirection(vec3 normal, inout uint rng_state) { vec3 direction = randomDirection(rng_state); return (direction * sign(dot(normal, direction))); }