Function refract

examples/cuda/gpu/path_tracer_gpu/src/math.rs:38–47

(v: Vec3, n: Vec3, ni_over_nt: f32)

}

pub fn refract(v: Vec3, n: Vec3, ni_over_nt: f32) -> Option<Vec3> {
    let uv = v.normalized();
    let dt = uv.dot(n);
    let discriminant = 1.0 - ni_over_nt * ni_over_nt * (1.0 - dt * dt);
    if discriminant > 0.0 {
        Some(ni_over_nt * (uv - n * dt) - discriminant.sqrt() * n)
    } else {
        None
    }
}

pub fn schlick(cos: f32, ref_idx: f32) -> f32 {
    let r0 = (1.0 - ref_idx) / (1.0 + ref_idx);