CGAL users discussion list

[Laure Guicherd <>]

Hi all,
I'm kind of stuck with this issue with Voronoi 2D. I know this topic has 
been discussed a lot in this mailing, but I could not find a solution in 
the archives.

I am getting a Voronoi diagram from successive sites insertions, then i 
want to get its faces and vertices. Since i want to bound this diagram 
with a convex hull, i need to get the intersection of the diagram edges 
with this hull, and in this purpose i want to convert each halfedge to 
Segment_2 or Ray_2 in order to test this intersection.

Here is my (simplified) code :



typedef typename CGAL::Delaunay_triangulation_2<K> DT;   
typedef typename CGAL::Delaunay_triangulation_adaptation_traits_2<DT> AT;
typedef typename 
CGAL::Delaunay_triangulation_caching_degeneracy_removal_policy_2<DT> AP;
typedef typename CGAL::Voronoi_diagram_2<DT,AT,AP> Voronoi;
typedef typename Voronoi::Face_iterator Face_iterator;
typedef typename Voronoi::Ccb_halfedge_circulator Ccb_halfedge_circulator;
typedef typename AT::Site_2 Site_2;


Voronoi VD;

// for each point [x,y] :
VD.insert( Site_2(x,y) );

for ( Face_iterator bf = VD.faces_begin() ; bf != VD.faces_end() ; ++bf )
{
   Ccb_halfedge_circulator firstEdge = (*bf).outer_ccb();
   Ccb_halfedge_circulator he = firstEdge;
   do
   {
       CGAL::Object obj = make_object(he);

       Segment_2 segment;
       Ray_2 ray;
       bool isSegment = ( CGAL::assign( segment, obj ) );
       bool isRay = ( CGAL::assign( ray, obj ) );

       // test intersection, get points, etc.
   }
   while ( ++he != firstEdge );
}


My problem is that isRay and isSegment always return false, even when 
he->is_ray() or he->is_segment() are true.

What did i do wrong ? How can i make this conversion ?
Any hint will be greatly appreciated, thank you !

Laure