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[Thomas Recouvreux <>]

Hi again,

In fact I would like to export my partition, for my export I need for example a list of indexed faces with the index of their neighbors.

I tried to put an "index" variable in FaceInfo, that works well when I iterate other faces (it->infos().index), but it->neighbor(i).info().index fails at compilation ( [...] Face_handle’ has no member named ‘info’).

Is their an easy way to export triangulation to halfedge structure ?

2012/2/6 Sebastien Loriot (GeometryFactory) <>

On 02/06/2012 05:23 PM, Thomas Recouvreux wrote:

2012/2/6 Sebastien Loriot (GeometryFactory) <

<mailto:>>

   On 02/06/2012 05:11 PM, Thomas Recouvreux wrote:

       Hi,

       Thanks the Delaunay triangulation works well.
       Do you have a piece of code to remove edges ?

   Do you mean removing constrained edges?

No I mean remove some edges to fusion triangle into convex polygons.

A triangulation is by definition triangulated, so you can't do that
with a Triangulation as underlying data structure.
To do that you need to export your triangulated polygon into another
data structure such as the Halfedge data structure for example
(http://www.cgal.org/Manual/latest/doc_html/cgal_manual/HalfedgeDS/Chapter_main.html)

       And is there an index for each faces or shall I put it in FaceInfo
       structure ?

   You need to use Face_with_info.
   Note that a Face_handle can be use as a key in a map for example.

How can I use Face_handle as a key ??

Face_handle object are comparable so you can use for example:

typedef std::set<Face_handle> Face_handle_set;

Sebastien.

   Sebastien.



       Thomas


       2012/1/18 Mariette Yvinec <
       <mailto:>

       <mailto:__fr

       <mailto:>>>


           Starting from the constrained triangulation of your polygons
           you can appraoch a minimal convex subdivision
           (I think at most twice the number of parts of the optimal)
           by pulling out as much as you can
           of non constrained triangulation edges
           without forming angles greater than 90 degrees.

           Le 18/01/12 09:27, Sebastien Loriot (GeometryFactory) a écrit :

               The input polygon should be simple and without holes.
               In you case you might want to try to use a constrained
           (Delaunay)
               triangulation (edges of your polygon are constraints).
               The decomposition would be minimal at all but it will be
           convex.


               See:

           http://www.cgal.org/Manual/__latest/doc_html/cgal_manual/__Triangulation_2/Chapter_main.__html#Section_36.7

           <http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Triangulation_2/Chapter_main.html#Section_36.7>


               Sebastien.

               Thomas Recouvreux wrote:

                   Hi,

                   I've have found some examples about partitionning a
               Polygon_2,
                   but I didn't see functions for partitionning a
               Poly_2 with holes.
                   Is there any function to do so or shall I decompose
               first my
                   polygon with holes in polygons without holes and
               apply the
                   partitionning function ?

                   An other question, I tried to use partition function
               on a polygon
                   with tangente edges (see below), and the function
               return the
                   whole polygon without partionning it, did I miss
               something ?

                   +-----------------------------__----------+
                   |                                       / |
                   |                                     /   |
                   |                        +----------+   |
                   |                         |           |    |
                   |                        +----------+   |
                   |                                         |
                   |                                         |
                   +-----------------------------__----------+

                   polygon.push_back(Point_2(0, 0));
                   polygon.push_back(Point_2(10, 0));
                   polygon.push_back(Point_2(6, 2));
                   polygon.push_back(Point_2(2, 2));
                   polygon.push_back(Point_2(2, 6));
                   polygon.push_back(Point_2(6, 6));
                   polygon.push_back(Point_2(6, 2));
                   polygon.push_back(Point_2(10, 0));
                   polygon.push_back(Point_2(10, 10));

                   polygon.push_back(Point_2(0,__10));

                   Best
                   Thomas




           --
           Mariette Yvinec
           Geometrica project team
           INRIA  Sophia-Antipolis






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