Polyhedron/polyhedron_prog_cube.cpp

#include <CGAL/Simple_cartesian.h>
#include <CGAL/Polyhedron_3.h>
#include <iostream>
 
template <class Poly>
typename Poly::Halfedge_handle make_cube_3( Poly& P) {
    // appends a cube of size [0,1]^3 to the polyhedron P.
    CGAL_precondition( P.is_valid());
    typedef typename Poly::Point_3         Point;
    typedef typename Poly::Halfedge_handle Halfedge_handle;
    Halfedge_handle h = P.make_tetrahedron( Point( 1, 0, 0),
                                            Point( 0, 0, 1),
                                            Point( 0, 0, 0),
                                            Point( 0, 1, 0));
    Halfedge_handle g = h->next()->opposite()->next();             // Fig. (a)
    P.split_edge( h->next());
    P.split_edge( g->next());
    P.split_edge( g);                                              // Fig. (b)
    h->next()->vertex()->point()     = Point( 1, 0, 1);
    g->next()->vertex()->point()     = Point( 0, 1, 1);
    g->opposite()->vertex()->point() = Point( 1, 1, 0);            // Fig. (c)
    Halfedge_handle f = P.split_facet( g->next(),
                                       g->next()->next()->next()); // Fig. (d)
    Halfedge_handle e = P.split_edge( f);
    e->vertex()->point() = Point( 1, 1, 1);                        // Fig. (e)
    P.split_facet( e, f->next()->next());                          // Fig. (f)
    CGAL_postcondition( P.is_valid());
    return h;
}
 
typedef CGAL::Simple_cartesian<double>     Kernel;
typedef CGAL::Polyhedron_3<Kernel>         Polyhedron;
typedef Polyhedron::Halfedge_handle        Halfedge_handle;
 
int main() {
    Polyhedron P;
    Halfedge_handle h = make_cube_3( P);
    return (P.is_tetrahedron(h) ? 1 : 0);
}