CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Let me rephrase to see if I got your question right:
You have an ordered sequence of points on a triangle mesh
(defining a polyline) and you would like to get the polyline
"segments" on the surface mesh between each consecutive pair of points.

Am I right?

Sebastien.


On 06/16/2017 04:54 PM, TONG FU wrote:
> Sorry for my language.
>    I have some polylines on a triangulate surface. I want to find the
> shortest path between each two point of these polylines. So I use the
> package  'triangulated surface mesh shortest path'. I set all points on
> a polyline as a set of source points S.  I have a target point t. If I
> want to find the shortest path between t and S(3), what should I do?
>
>
>
> 2017-06-16 16:32 GMT+02:00 Sebastien Loriot (GeometryFactory)
> <
>  
> <mailto:>>:
>
>     Could you rephrase your question, because it is not clear to me what you
>     want to know.
>
>     Thanks,
>
>     Sebastien.
>
>     On 06/16/2017 04:11 PM, Tong wrote:
>
>         Hello,
>
>         I'm now working on the calculation of shortest path between two
>         points. I
>         have a sequence of the source points. Is it possible to
>         calculate the
>         shortest path between my target point and one of the source
>         points (for
>         example, the third point in this sequence)?
>
>         Here is my solution. Since each time I remove a source point,
>         the sequence
>         tree rebuilds. It takes to much time to get the resultat.
>                face_iterator fit, fit_end;
>                 boost::tie(fit, fit_end) = faces(polyhedron);
>                 std::vector<face_descriptor> face_vector(fit, fit_end);
>                 const std::size_t nb_source_points = n_vertices;
>                 Traits::Barycentric_coordinate face_location = {{0.25,
>         0.5, 0.25}};
>                 std::vector<Face_location> faceLocations(nb_source_points,
>         Face_location(face_descriptor(), face_location));
>                 for (j = 0; j < nb_source_points; ++j)
>                 {
>
>         
> faceLocations[j].first=face_vector[boost::lexical_cast<int>(face_id[j])];
>                 }
>                 std::cout<<"construct a shortest path query object and
>         add a range
>         of source points..."<<std::endl;
>                 Surface_mesh_shortest_path shortest_paths(polyhedron);
>                 shortest_paths.add_source_points(faceLocations.begin(),
>         faceLocations.end());
>                 std::cout&lt;&lt;&quot;add source points for one polyline
>         finished&quot;&lt;&lt;std::endl;
>                 shortest_paths.source_points_begin();
>
>                 //calculate the shortest path bewteen two points
>                 for(j = 0;j&lt;n_vertices-1;j++){
>
>         
> shortest_paths.remove_source_point(shortest_paths.source_points_begin());
>                     face_iterator face_it = faces(polyhedron).first;
>
>         std::advance(face_it,boost::lexical_cast&lt;int>(face_id[j]));
>                     // collect the sequence of simplicies crossed by the
>         shortest
>         path
>                     Sequence_collector sequence_collector;
>
>         shortest_paths.shortest_path_sequence_to_source_points(*face_it,
>         face_location, sequence_collector);
>         }
>
>
>         Thank you.
>
>
>
>         --
>         View this message in context:
>         
> http://cgal-discuss.949826.n4.nabble.com/Triangulated-Surface-Mesh-Shortest-Paths-tp4662769.html
>         
> <http://cgal-discuss.949826.n4.nabble.com/Triangulated-Surface-Mesh-Shortest-Paths-tp4662769.html>
>         Sent from the cgal-discuss mailing list archive at Nabble.com.
>
>
>
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