CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Song Lin wrote:
> Dear sebastien,
>
> Thank you for your reply.
>
> but there is another problem:
>
> the types in my codes are:
>
>
> typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
>
> typedef CGAL::Regular_triangulation_euclidean_traits_3<K> Gt;
>
> typedef CGAL::Alpha_shape_vertex_base_3<Gt>         Vb;
> typedef CGAL::Alpha_shape_cell_base_3<Gt>           Fb;
> typedef CGAL::Triangulation_data_structure_3<Vb,Fb> Tds;
> typedef CGAL::Regular_triangulation_3<Gt,Tds>       Triangulation_3;
> typedef CGAL::Alpha_shape_3<Triangulation_3>        Alpha_shape_3;
>
>
> and it's ok for this function:
>
> as.classify(vit,0) 
> (as is Alpha_shape_3 and vit is Finite_vertices_iterator)
>
> but when I replace this line
>
> typedef CGAL::Alpha_shape_vertex_base_3<Gt>         Vb;
>
> to this
>
> typedef CGAL::Triangulation_vertex_base_with_info_3<int, K> Vb;

You did not read carefully what I wrote.
you should have written:

 typedef CGAL::Alpha_shape_vertex_base_3<Gt>         Vb_as;
 typedef CGAL::Triangulation_vertex_base_with_info_3<int, K,Vb_as> Vb;


> the function "as.classify(vit,0)" doesn't work.
>
>
>
> It looks like what I need is something like
> "Alpha_shape_vertex_base_with_info_3"
>
> as what I want to do is:
>
> for (vit = as.finite_vertices_begin(); vit !=
> as.finite_vertices_end();vit++)
> {
>         if(as.classify(vit,0)==Alpha_shape_3::EXTERIOR)
>         {
>                 l++;
>                 vit->info()=0;
>         }
>         else
>         {
>                 vit->info()=1;
>         }
> }
>
> that decides which "vit" belongs to "as" and which doesn't.
>
> Do you have any suggestion about this problem? Thank you.
>
> Lin
>
> 在 2010-04-21三的 09:02 +0200，Sebastien Loriot (GeometryFactory)写道：
> > Song Lin wrote:
> > > Hello everyone,
> > >
> > > I want to mark some vertices(facets,edges...) of a triangulation, but I
> > > don't know how.
> > >
> > > part of my codes are:
> > >
> > > list<Weighted_point> lwp;
> > > Alpha_shape_3  as(lwp.begin(), lwp.end(), 0, Alpha_shape_3::GENERAL);
> > > Alpha_shape_3::Finite_vertices_iterator vit;
> > > for (vit = as.finite_vertices_begin(); vit !=
> > > as.finite_vertices_end();vit++)
> > > {
> > >         if(as.classify(vit,0)==Alpha_shape_3::REGULAR)
> > >         {
> > >                 ##### mark vit; #####
> > >         }
> > > }
> > >
> > > and then I want to do:
> > >
> > > for(all vit)
> > > {
> > >         if(vit was marked)
> > >         then(......)
> > > }
> > >
> > >
> > > Can anyone tell me how to mark a Vertex_handle(Facet,Edge...)? I read
> > > the reference of triangulation but couldn't find a solution. Thanks.
> > >
> > > Best regards,
> > > Lin
> > Have a look here
> >
> > http://www.cgal.org/Manual/last/doc_html/cgal_manual/Triangulation_3/Chapter_main.html#Subsection_37.5.2
> >
> > and here
> >
> > at the documentation of Triangulation_vertex_base_with_info_3
> > http://www.cgal.org/Manual/last/doc_html/cgal_manual/Triangulation_3_ref/Class_Triangulation_vertex_base_with_info_3.html#Cross_link_anchor_1327
> >
> > In you case if your vertex type is Vb, you should use
> > CGAL::Triangulation_vertex_base_with_info_3<YOUR_INFO,YOUR_KERNEL,Vb>
> >
> >
> > S.