func (v Vec3) LenSqr() float32 {
	return v[0]*v[0] + v[1]*v[1] + v[2]*v[2]
}
func (v Vec3) LenSqr() float32 {
	return v[0]*v[0] + v[1]*v[1] + v[2]*v[2]
}
// LenSqr derives the square of the scalar length of the vector. (len * len)