CGAL users discussion list

Hi Satyajit,

just use the following function for v = the infinite vertex

template <class OutputIterator>
OutputIterator  t.incident_cells ( Vertex_handle v, OutputIterator cells)
		Copies the Cell_handles of all cells incident to v to the output 
iterator cells. If t.dimension() <3, then do nothing. Returns the 
resulting output iterator.
Precondition:   v Vertex_handle(), t.is_vertex(v).

best,
        Monique Teillaud

Satyajit Sarangi wrote:
> Hi Laurent,
>             Thanx for the answer. However, the result which I was 
> expecting didn't turn out. What I exactly wanted to do was to get the 
> convex hull of certain points in 3D by using Delaunay triangulation and 
> then only considering the cells which were infinite and extracting the 
> finite triangle from the cells. It would be great if you could give me 
> an idea about how to go about it.
> Thanx
> Satyajit
>
> On 8/7/07, *Laurent Rineau* < 
> <mailto:>> wrote:
>
>     On Wednesday 08 August 2007 01:04:56 Satyajit Sarangi wrote:
>      > Hi all,
>      >        am new to cgal and was trying to extract the finite
>     triangle from an
>      > infinite cell and was wondering how to do it. I was also
>     wondering if there
>      > was a way by which if there was an iterator for the infinite cells.
>
>     Hi,
>
>     I assume that ch is the cell handle of an infinite cell, and tr is the
>     triangulation (of type Tr).
>
>     const int index = ch->index(tr.infinite_vertex()); // here is the trick
>     Point_3 pa = ch->vertex((index+1)&3)->point();
>     Point_3 pb = ch->vertex((index+2)&3)->point();
>     Point_3 pc = ch->vertex((index+3)&3)->point();
>
>     then Triangle_3(pa, pb, pc) is the finite triangle of ch.
>
>     --
>     Laurent Rineau
>     INRIA - Sophia Antipolis
>     BP 93, 2004 Route des Lucioles
>     06902 Sophia Antipolis Cedex FRANCE
>     Tel: +33 4 92 38 78 62
>     --
>     You are currently subscribed to cgal-discuss.
>     To unsubscribe or access the archives, go to
>     https://lists-sop.inria.fr/wws/info/cgal-discuss
>     <https://lists-sop.inria.fr/wws/info/cgal-discuss>