CGAL users discussion list

[Andreas Fabri <>]

Hello,

In your code I don't see how vertices make it into
the vector. If you just create a vector with 800 Vertex_handles
you have just 800 pointers to NULL.

You refer to a function incident_vertices, but you don't
show us how you use it

andreas


Kwok Jasper wrote:
> Thank you very much
> 
> and for the following for calling the incident_vertices function
> 
>  > > typedef CGAL::Exact_predicates_inexact_constructions_kernel K1;
>  > > typedef CGAL::Delaunay_triangulation_3<K1> Triangulation;
>  > > typedef Triangulation::Point Point_tr;
>  > >
>  > > Triangulation Tr;
>  > >
>  > > Vertex_handle v = Tr.insert(Point_tr(0,0,0));
>  > > Tr.insert(Point_tr(40,20,10));
>  > > //...insert some more points
>  > >
>  > > vector<Vertex_handle> con;
>  > > con.resize(800);
>  > >
>  > > vector <Vertex_handle>::iterator start_inci = con.begin();
>  > > vector<Vertex_handle>::iterator end_inci = con.end();
>  > > vector<Vertex_handle>::iterator curr_inci;
>  > >
>  > > for(curr_inci = start_inci; curr_inci != end_inci; ++curr_inci)< 
> br>> > {
>  > > //do sth with the vertex handles.
>  > > }
> 
> 
> may I ask if it is a proper way to use it.
> In the method , I use  con.resize(800);
> If I didn't use the resize() function there.
> then it have a exception telling that the iterator cannot be deferenced
> May I ask if the above code is a proper way to use the 
> incident_vertices() function ?
> 
> Thank you
> 
> 
> 
>  > Date: Thu, 22 Jan 2009 15:23:24 +0100
>  > From: 
> 
>  > To: 
> 
>  > Subject: Re: [cgal-discuss]
>  >
>  > Kwok Jasper wrote:
>  > > Excuse me, may I ask something?
>  > >
>  > > I have tried the code below
>  > > and I am not sure if I have used the function incident_vertices 
> correctly.
>  > > May I ask if anyone is willing to tell me whether I have used that
>  > > function properly?
>  > >
>  > >
>  > > typedef CGAL::Exact_predicates_inexact_constructions_kernel K1;
>  > > typedef CGAL::Delaunay_triangulation_3<K1> Triangulation;
>  > > typedef Triangulation::Point Point_tr;
>  > >
>  > > Triangulation Tr;
>  > >
>  > > Vertex_handle v = Tr.insert(Point_tr(0,0,0));
>  > > Tr.insert(Point_tr(40,20,10));
>  > > //...insert some more points
>  > >
>  > > vector<Vertex_handle> con;
>  > > con.resize(800);
>  > >
>  > > vector <Vertex_handle>::iterator start_inci = con.begin();
>  > > vector<Vertex_handle>::iterator end_inci = con.end();
>  > > vector<Vertex_handle>::iterator curr_inci;
>  > >
>  > > for(curr_inci = start_inci; curr_inci != end_inci; ++curr_inci)
>  > > {
>  > > //do sth with the vertex handles.
>  > > }
>  > >
>  > >
>  > > And may I ask one more thing?
>  > > If there is a Vertex_handle v, then is it possible to get the x, y
>  > > coordinate of the vertex represented by v?
>  > > I have looked at the manual of 2D and 3D triangulation and cannot find
>  > > any examples about it.
>  > > May I ask if there is some method for doing that?
>  > >
>  > > Thank you very much for your attention.
>  >
>  > Once you have found the reference manual page for Vertex, things will
>  > become obvious.
>  >
>  > On this page
>  > 
> http://www.cgal.org/Manual/3.4/doc_html/cgal_manual/Triangulation_2_ref/Class_Triangulation_2.html
>  >
>  > scroll down to the end, and click on
>  >
>  > TriangulationDataStructure_2::Face
>  > TriangulationDataStructure_2::Vertex
>  >
>  > to see what you can do with a vertex.
>  >
>  > andreas
>  >
>  >
>  > >
>  > >
>  > >
>  > >
>  > > 
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