C++ Facet_iterator::facet_degree方法代码示例

//.........这里部分代码省略.........
  mwSize nrowsTri = mxGetM(inTRI->pm);
  mwSize nrowsX = mxGetM(inX->pm);

#ifdef DEBUG  
  std::cout << "Number of facets read = " << mesh.size_of_facets() << std::endl;
  std::cout << "Number of vertices read = " << mesh.size_of_vertices() << std::endl;
#endif

  if (nrowsTri != mesh.size_of_facets()) {
    mexErrMsgTxt(("Input " + inTRI->name + ": Number of triangles read into mesh different from triangles provided at the input").c_str());
  }
  if (nrowsX != mesh.size_of_vertices()) {
    mexErrMsgTxt(("Input " + inX->name + ": Number of vertices read into mesh different from vertices provided at the input").c_str());
  }

  // sort halfedges such that the non-border edges precede the
  // border edges. We need to do this before any halfedge iterator
  // operations are valid
  mesh.normalize_border();
  
#ifdef DEBUG
  std::cout << "Number of border halfedges = " << mesh.size_of_border_halfedges() << std::endl;
#endif
  
  // number of holes we have filled
  mwIndex n = 0;

  // a closed mesh with no holes will have no border edges. What we do
  // is grab a border halfedge and close the associated hole. This
  // makes the rest of the iterators invalid, so we have to normalize
  // the mesh again. Then we iterate, looking for a new border
  // halfedge, filling the hole, etc.
  //
  // Note that confusingly, mesh.border_halfedges_begin() gives a
  // pointer to the halfedge that is NOT a border in a border
  // edge. The border halfedge is instead
  // mesh.border_halfedges_begin()->opposite()
  while (!mesh.is_closed()) {
    
    // exit if user pressed Ctrl+C
    ctrlcCheckPoint(__FILE__, __LINE__);

    // get the first hole we can find, and close it
    mesh.fill_hole(mesh.border_halfedges_begin()->opposite());

    // increase the counter of number of holes we have filled
    n++;

    // renormalize mesh so that halfedge iterators are again valid
    mesh.normalize_border();

  }

  // split all facets to triangles
  CGAL::triangulate_polyhedron<Polyhedron>(mesh);

  // copy output with number of holes filled
  std::vector<double> nout(1, n);
  matlabExport->CopyVectorOfScalarsToMatlab<double, std::vector<double> >(outN, nout, 1);

  // allocate memory for Matlab outputs
  double *tri = matlabExport->AllocateMatrixInMatlab<double>(outTRI, mesh.size_of_facets(), 3);

   // extract the triangles of the solution
  // snippet adapted from CgalMeshSegmentation.cpp

  // vertices coordinates. Assign indices to the vertices by defining
  // a map between their handles and the index
  std::map<Vertex_handle, int> V;
  int inum = 0;
  for(Vertex_iterator vit = mesh.vertices_begin(); vit != mesh.vertices_end(); ++vit) {

    // save to internal list of vertices
    V[vit] = inum++;

  }  

  // triangles given as (i,j,k), where each index corresponds to a vertex in x
  mwIndex row = 0;
  for (Facet_iterator fit = mesh.facets_begin(); fit != mesh.facets_end(); ++fit, ++row) {

    if (fit->facet_degree() != 3) {
      std::cerr << "Facet has " << fit->facet_degree() << " edges" << std::endl;
      mexErrMsgTxt("Facet does not have 3 edges");
    }

    // go around the half-edges of the facet, to extract the vertices
    Halfedge_around_facet_circulator heit = fit->facet_begin();
    int idx = 0;
    do {
      
      // extract triangle indices and save to Matlab output
      // note that Matlab indices go like 1, 2, 3..., while C++ indices go like 0, 1, 2...
      tri[row + idx * mesh.size_of_facets()] = 1 + V[heit->vertex()];
      idx++;

    } while (++heit != fit->facet_begin());
    
  }
}