#define M_PI 3.14159265359 float randomValue(inout uint rng_state) { rng_state = rng_state * 747796405u + 2891336453u; uint result = ((rng_state >> ((rng_state >> 28u) + 4u)) ^ rng_state) * 277803737u; result = (result >> 22u) ^ result; return (float(result) * (1.0 / 4294967295.0)); } float randomValueNormalDistribution(inout uint rng_state) { float theta = 2.0 * M_PI * 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)); } vec2 randomPointInCircle(inout uint rng_state) { float angle = randomValue(rng_state) * 2 * M_PI; vec2 point_in_circle = vec2(cos(angle), sin(angle)); return (point_in_circle * sqrt(randomValue(rng_state))); } vec3 randomHemisphereDirection(vec3 normal, inout uint rng_state) { vec3 direction = randomDirection(rng_state); return (direction * sign(dot(normal, direction))); }