void trisect_border_halfedge( Polyhedron& P, Halfedge_handle e) {
CGAL_precondition( e->is_border());
// Create two new vertices on e.
e = e->prev();
P.split_vertex( e, e->next()->opposite());
P.split_vertex( e, e->next()->opposite());
e = e->next();
// We use later for the smoothing step that e->next()->next()
// is our original halfedge we started with, i.e., its vertex is
// from the unrefined mesh. Split the face twice.
Halfedge_handle h = e->opposite()->next();
P.split_facet( e->next()->next()->opposite(), h);
P.split_facet( e->next()->opposite(), h);
}
void flip_edge( Polyhedron& P, Halfedge_handle e) {
if ( e->is_border_edge())
return;
Halfedge_handle h = e->next();
P.join_facet( e);
P.split_facet( h, h->next()->next());
}
void geometryUtils::subdivide_flip_edge(Polyhedron& P, Halfedge_handle e) {
Halfedge_handle h = e->next();
P.join_facet(e);
P.split_facet(h, h->next()->next());
}
