1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
|
#include <CGAL/Simple_cartesian.h>
#include <CGAL/Linear_cell_complex_for_combinatorial_map.h>
#include <CGAL/boost/graph/graph_traits_Linear_cell_complex_for_combinatorial_map.h>
#include <CGAL/IO/polygon_mesh_io.h>
#include <CGAL/Mean_curvature_flow_skeletonization.h>
#include <fstream>
typedef CGAL::Simple_cartesian<double> Kernel;
typedef Kernel::Point_3 Point;
typedef CGAL::Linear_cell_complex_traits<3, Kernel> MyTraits;
typedef CGAL::Linear_cell_complex_for_bgl_combinatorial_map_helper
<2, 3, MyTraits>::type LCC;
typedef boost::graph_traits<LCC>::vertex_descriptor vertex_descriptor;
typedef CGAL::Mean_curvature_flow_skeletonization<LCC> Skeletonization;
typedef Skeletonization::Skeleton Skeleton;
typedef Skeleton::vertex_descriptor Skeleton_vertex;
typedef Skeleton::edge_descriptor Skeleton_edge;
int main()
{
LCC lcc;
CGAL::IO::read_polygon_mesh(CGAL::data_file_path("meshes/elephant.off"), lcc);
Skeleton skeleton;
Skeletonization mcs(lcc);
// 1. Contract the mesh by mean curvature flow.
mcs.contract_geometry();
// 2. Collapse short edges and split bad triangles.
mcs.collapse_edges();
mcs.split_faces();
// 3. Fix degenerate vertices.
mcs.detect_degeneracies();
// Perform the above three steps in one iteration.
mcs.contract();
// Iteratively apply step 1 to 3 until convergence.
mcs.contract_until_convergence();
// Convert the contracted mesh into a curve skeleton and
// get the correspondent surface points
mcs.convert_to_skeleton(skeleton);
std::cout << "Number of vertices of the skeleton: " << boost::num_vertices(skeleton) << "\n";
std::cout << "Number of edges of the skeleton: " << boost::num_edges(skeleton) << "\n";
// Output all the edges of the skeleton.
std::ofstream output("skel-lcc.polylines.txt");
for(Skeleton_edge e : CGAL::make_range(edges(skeleton)))
{
const Point& s = skeleton[source(e, skeleton)].point;
const Point& t = skeleton[target(e, skeleton)].point;
output << "2 "<< s << " " << t << "\n";
}
output.close();
// Output skeleton points and the corresponding surface points
output.open("correspondance-lcc.polylines.txt");
for(Skeleton_vertex v : CGAL::make_range(vertices(skeleton)))
for(vertex_descriptor vd : skeleton[v].vertices)
output << "2 " << skeleton[v].point << " " << get(CGAL::vertex_point, lcc, vd) << "\n";
return 0;
}
|
