public:
Skyline ();
Skyline (Skyline const &src);
Skyline (Direction sky);
Skyline (vector<Box> const &bldgs, Real horizon_padding, Axis a, Direction sky);
Skyline (Box const &b, Real horizon_padding, Axis a, Direction sky);
public:
Skyline ();
Skyline (Skyline const &src);
Skyline (Direction sky);
Skyline (vector<Box> const &bldgs, Real horizon_padding, Axis a, Direction sky);
Skyline (Box const &b, Real horizon_padding, Axis a, Direction sky);