/**
* Returns the reflection of a vector u on a surface with normal n. Vector u points towards the
* surface, vector r (result) points away from the surface. n is assumed to be normalized.
*
* @param u vector that will be reflected on the surface
* @param n normal of the surface
* @return reflected vector, facing away from the surface
*/
public static Vector3 reflect(Vector3 u, Vector3 n) {
double scalar = Vector3.dotProduct(u, n) * -2d;
Vector3 result = Vector3.timesScalar(n, scalar);
result = Vector3.add(result, u);
return result;
}
