public Matrix4f InitRotation(Vector4f forward, Vector4f up)
        {
            Vector4f f = forward.Normalized();

            Vector4f r = up.Normalized();

            r = r.Cross(f);

            Vector4f u = f.Cross(r);


            return(InitRotation(f, u, r));
        }
        public Matrix4f InitRotation(Vector4f forward, Vector4f up)
        {
            Vector4f f = forward.Normalized();

             		    Vector4f r = up.Normalized();
             		    r = r.Cross(f);

             		    Vector4f u = f.Cross(r);

             		    return InitRotation(f, u, r);
        }