/** @brief rotate in the given direction
* @tparam VEC point type including POINT::Scalar as coord type
* @param _direction vector which points in the desired direction
*/
template<class VEC> void glRotate(const VEC& _direction)
{
// get coordinate type from vector type
typedef typename VEC::scalar_type Scalar;
// pre-calculate vector length
Scalar length = _direction.length();
// calculate phi and theta (@link http://de.wikipedia.org/wiki/Kugelkoordinaten#.C3.9Cbliche_Konvention)
Scalar phi = tomo::rad2deg( atan2(_direction.y(), _direction.x()) );
Scalar theta = (0.0 != length) ? tomo::rad2deg(acos( (_direction.z() / length) )) : 0.0;
// rotate GL world
glRotate(phi,theta);
}
