CGAL users discussion list

[Peter Hachenberger <>]

Sorry, I must ask more precisely. What kind of triangulation do you use?
Is it from CGAL? If yes, which triangulation?

On Wed, 2007-07-18 at 16:51 +0200, Thomas Zangl - Home wrote:
>  Am Wed, 18 Jul 2007 16:15:05 +0200, schrieb "Peter Hachenberger" 
> <>:
> 
> Hi!
> 
> >How do you extract the vertices from a triangle? I'm not completely sure
> >how our triangulation works, but I would assume that the vertices of a
> >facet should be oriented consistently if you triangulate an orientable
> >surface.
> 
> I extract them like this:
> 
>   Rt_Facet_iterator fIt = t.facets_begin();
>   Rt_Facet_iterator fEnd = t.facets_end();
>   if ( fIt == fEnd ) { std::cout << "no faces found" << std::endl ;}
>   else {
>     while(fIt != fEnd) {
>       Rt_Cell_handle cell = fIt->first;
>       // this is the index of the facet's opposite vertex
>       int faceIndex = fIt->second;
>       // "info" is a simple int which holds an index, assigned
>       // upon insertion into the triangulation.
>       // bascially its just 0, 1, 2, 3, 4, 5 ... 
>       int a = cell->vertex((faceIndex+1) % 4)->info();
>       int b = cell->vertex((faceIndex+2) % 4)->info();
>       int c = cell->vertex((faceIndex+3) % 4)->info();
>       
>       // I then test here if the triangle is useful for later
>       // processing..
>       if (isUseFull) {
>         intTriple faceOfIndices(a,b,c);
>         complex.push_back(faceOfIndices);
>       }  
>   }
>   
> So I end up with a vector of intTriple (which hold the indices of the
> points forming each facet in the vector). And I have another vector
> where I have a mapping index -> point which I need later for building
> the Polyhedron. 
> Nothing special :-)
> 
> Best regards,
> -- 
> ----------------------------------------------------------------
> ,yours Thomas Zangl, Bakk.rer.soc.oec. - 
> 
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