Add edge_polyline_map as NP to split_long_edges()

[yDF8EPJN8]

Issue Details

My issue is similar to Add face_patch_map as NP to split_long_edges().

I'm asking to add another property to the Named Parameters for the split_long_edges() function, which is similar to face_patch_map, but for the edges that the function will split.

I'm working with geometry from CAD. For each model I have face_patch_map for triangles and edge_polyline_map with boost::graph_traits<PolygonMesh>::edge_descriptor as key type and int as value type.

I want the edges resulting from the splitting of edges belonging to a polyline to retain that property (i.e. the index of the polyline).

At the moment I'm solving this problem by assigning patch indices to the triangles around the polylines, but I think it would be as simple as the face_patch_map_solution.

Source Code

#include <iostream>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Polygon_mesh_processing/remesh.h>
#include <CGAL/Surface_mesh.h>

typedef CGAL::Exact_predicates_inexact_constructions_kernel   Kernel;
typedef Kernel::Point_3                                       Point;
typedef Kernel::Vector_3                                      Vector;
typedef CGAL::Surface_mesh<Point>                             Mesh;
typedef Mesh::Vertex_index                                    vertex_descriptor;
typedef Mesh::Edge_index                                      edge_descriptor;
typedef Mesh::Face_index                                      face_descriptor;

int main() {
  Mesh m;
  // triangle
  vertex_descriptor v1 = m.add_vertex(Point(0, 0, 0));
  vertex_descriptor v2 = m.add_vertex(Point(1, 0, 0));
  vertex_descriptor v3 = m.add_vertex(Point(0, 1, 0));
  face_descriptor f = m.add_face(v1, v2, v3);

  // edge polyline map
  auto e2p = m.add_property_map<edge_descriptor, int>("e:polyline", -1).first;
  // mark the edges on the line between p and q
  Point p(1, 0, 0);
  Point q(0, 1, 0);
  for (auto e : m.edges()) {
    Point p1 = m.point(m.vertex(e, 0));
    Point p2 = m.point(m.vertex(e, 1));
    if (CGAL::collinear(p, q, p1) && CGAL::collinear(p, q, p2))
      e2p[e] = 1;
  }
  std::cout << "edge polyline map before splitting\n";
  for (auto e : m.edges()) {
    Point p1 = m.point(m.vertex(e, 0));
    Point p2 = m.point(m.vertex(e, 1));
    std::cout << e.idx() << '\t' << e2p[e] << "\t(" << p1 << ")\t(" << p2 << ")\n";
  }

  CGAL::Polygon_mesh_processing::split_long_edges(m.edges(), 1.0, m);

  std::cout << "edge polyline map after splitting\n";
  for (auto e : m.edges()) {
    Point p1 = m.point(m.vertex(e, 0));
    Point p2 = m.point(m.vertex(e, 1));
    std::cout << e.idx() << '\t' << e2p[e] << "\t(" << p1 << ")\t(" << p2 << ")\n";
  }

  return 0;
}

The current output:

edge polyline map before splitting
0       -1      (1 0 0) (0 0 0)
1       1       (0 1 0) (1 0 0)
2       -1      (0 0 0) (0 1 0)
edge polyline map after splitting
0       -1      (1 0 0) (0 0 0)
1       1       (0 1 0) (0.5 0.5 0)
2       -1      (0 0 0) (0 1 0)
3       -1      (1 0 0) (0.5 0.5 0)
4       -1      (0 0 0) (0.5 0.5 0)

I expect it like

edge polyline map before splitting
0       -1      (1 0 0) (0 0 0)
1       1       (0 1 0) (1 0 0)
2       -1      (0 0 0) (0 1 0)
edge polyline map after splitting
0       -1      (1 0 0) (0 0 0)
1       1       (0 1 0) (0.5 0.5 0)
2       -1      (0 0 0) (0 1 0)
3       1       (1 0 0) (0.5 0.5 0)
4       -1      (0 0 0) (0.5 0.5 0)

Environment

• Operating system (Windows/Mac/Linux, 32/64 bits): Windows 64 bits
• Compiler: visual c++
• Release or debug mode:
• Specific flags used (if any):
• CGAL version: 6.0.1
• Boost version: 1.86
• Other libraries versions if used (Eigen, TBB, etc.):