CGAL - how to use CGAL::Polygon_mesh_processing::connected_components to convert one CGAL::Surface_mesh into many?

Question

I am creating a mesh utility library, and one of the functionalities that I would like to include is the ability to break apart disjoint partitions of a mesh. To that end, I am trying to write a method that takes in a CGAL::Surface_mesh and returns a std::vector<CGAL::Surface_mesh> , where each element is a connected component of the input mesh.

I see that CGAL has CGAL::Polygon_mesh_processing::connected components function, but that just seems to assign a label to each face indicating which component it's a part of. How can I use the result of that operation to construct a new CGAL::Surface_mesh from every group of faces with the same label?

Answer 1

One way of doing this is to use the result of connected_components() as input parameter for the Face_filtered_graph . You can do something like that I believe:

 FCCmap fccmap = mesh.add_property_map<face_descriptor, faces_size_type> 
                 ("f:CC").first;
 faces_size_type num = PMP::connected_components(mesh,fccmap); 
 std::vector<Mesh> meshes(num);
 for(int i=0; i< num; ++i)
 {
   Filtered_graph ffg(mesh, i, fccmap);
   CGAL::copy_face_graph(ffg, meshes[i]);
 }