CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

The vertex is not removed if the placement returns an
an "empty" optional.

Sebastien.

On 03/15/2014 03:38 AM, Zohar wrote:
> Hi,
>
> I'm using the placement strategy below that leaves the surviving vertex v1
> (no border) in place (v0 is deleted). I was wondering what cost scheme would
> make sense here (and why). For example, when I used LindstromTurk_cost, I
> tend to get nasty slivers.
>
> BTW, the following sentence in the doc is confusing:
>
> http://doc.cgal.org/latest/Surface_mesh_simplification/index.html#title3
>
> "The GetPlacement policy is called to compute the new position for the
> remaining vertex after the halfedge-collapse. It returns an optional value,
> which can be absent, in which case the remaining vertex is kept in its
> place."
>
> It says that the placement of v1 would be the same, while actually it means
> that the edge won't be collapsed and both v1 and v0 would stay in place.
>
> ---------------
>
> template<class ECM_>
> struct MyPlacement {
>         typedef ECM_ ECM;
>         typedef SMS::Edge_profile<ECM> Profile;
>         typedef typename CGAL::halfedge_graph_traits<ECM>::Point Point;
>         typedef SMS::optional<Point> result_type;
>
>         MyPlacement(vector<bool> &supp_) : supp(supp_) {}
>
>         result_type operator()(Profile const& ap) const  {
>                 int i = ap.v0()->id(), j = ap.v1()->id();
>                 result_type r = ap.p1(); // optional - if left unassigned, 
> then vertex
> isn't removed?
>                 return r;
>         }
>
>         vector<bool> &supp;
> };
>
>
>
> --
> View this message in context: 
> http://cgal-discuss.949826.n4.nabble.com/Simplification-stay-in-place-cost-strategy-tp4658964.html
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