point2<T> overlap( const point2<T>& pt, const rect2<T>& rect ) {
// check if either is null
if( pt == point2<T>::null( ) || rect == rect2<T>::null( ) ) {
return point2<T>::null( );
}
// general case
else if( greater_equal( pt.x, rect.l ) &&
less_equal( pt.x, rect.r ) &&
greater_equal( pt.y, rect.t ) &&
less_equal( pt.y, rect.b ) ) {
return pt;
}
else {
return point2<T>::null( );
}
}
constexpr auto operator>=(T t, U u)
{ return greater_equal(t, u); }
