CGAL users discussion list

Manuel Caroli wrote:
> Thomas Zangl wrote:
>
> > Hi!
> >
> > I want to add some stati to a facet of a Triangulation_3. I found 
> > vertex_base_with_info and cell_base_with_info. So, what would you 
> > recommend to use to add some information on a per facet base? (best 
> > practice) I would need some structure (the info/statis) to be easly 
> > and fast accessable when iterating over the facets of the 
> > triangulation with a facet iterator.
>
> A facet is represented by a (Cell_handle,int) pair. Thus I would store 
> the information in a four-tuple in the cell (each entry of the 
> four-tuple corresponds to one facet). Then you can access it like:
> facet->first->info()->get_entry(facet->second)

I guess you mean facet.second

> The only drawback is that you have to store the info twice per facet.

If you store only a reference to the info, it is not so expensive, and 
it allows to easily share the same information between the two cells 
sharing the facet.

best
        Monique Teillaud
> But right now I don't see a 
> possibility to overcome this.
> If you store it in the vertex, then it is much more complicated to 
> "find" the corresponding facet. And also you don't know how many facets 
> are incident to a vertex.
>
> best
>
> Manuel