CGAL users discussion list

[Andreas fabri <>]

You should only mark instead of deleting. 

> On 17 Sep 2019, at 12:22, malcolm 
> <>
>  wrote:
> 
> Hi,
> I am using the Constrained Delaunay triangulation and I need to create a
> hole in a triangulation using a clipping rectangle. For this, I first add
> the cliprect points to the triangulation and then find all the faces that
> have a vertex within the clipping polygon. I then call delete_face on each
> of these faces.
> 
> Here's my code:
> 
>    std::vector<Face_handle> facesToDelete;
>    for (auto& fItr = tDelaunay.all_faces_begin();
>        fItr != tDelaunay.all_faces_end();
>        fItr++)
>    {
>        for (int i = 0; i < 3; i++)
>        {
>            auto& pt = fItr->vertex(i)->point();
>            
>            // holePolygon is the closed point polygon with methods to find 
> if a
> point lies on or inside the polygon
>            if (holePolygon.isPointInside(pt) && !holePolygon.isPointOn(pt)) 
> // if
> face vertex is in the interior of the hole polygon
>            {
>                facesToDelete.push_back(fItr);
>                break;
>            }
>        }
>    }
> 
>    for (auto& face : facesToDelete)
>    {
>        tDelaunay.delete_face(face);
>    }
> 
> 
> This works fine and I get the required hole. However, if I now add a vertex
> to this triangulation, I get a crash.
> 
> I have tried using the make_hole() method too, and even with this, I run
> into problems. Is there another way to create a hole in a CDT?
> 
> 
> 
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> Sent from: http://cgal-discuss.949826.n4.nabble.com/
> 
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