Function reflect

tools/bloom-reference/src/main.rs:1328–1330

(incoming: Vec3, normal: Vec3)

}

fn reflect(incoming: Vec3, normal: Vec3) -> Vec3 {
    incoming - normal * (2.0 * incoming.dot(normal))
}

fn smith_g1(n_dot_x: f32, alpha: f32) -> f32 {
    let a2 = alpha * alpha;