Added a test for snapping functions

Polygon_mesh_processing/test/Polygon_mesh_processing/CMakeLists.txt

@@ -101,6 +101,7 @@ endif()
   create_single_source_cgal_program("test_orient_cc.cpp")
   create_single_source_cgal_program("test_pmp_transform.cpp")
   create_single_source_cgal_program("extrude_test.cpp")
+  create_single_source_cgal_program("test_snap.cpp")
 
   if( TBB_FOUND )
     CGAL_target_use_TBB(test_pmp_distance)

Polygon_mesh_processing/test/Polygon_mesh_processing/test_snap.cpp

@@ -0,0 +1,110 @@
+#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
+#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
+
+#include <CGAL/Polyhedron_3.h>
+#include <CGAL/Polyhedron_items_with_id_3.h>
+#include <CGAL/Surface_mesh.h>
+
+#include <CGAL/Polygon_mesh_processing/internal/Snapping/snap.h>
+
+#include <iostream>
+#include <fstream>
+#include <set>
+
+namespace PMP = CGAL::Polygon_mesh_processing;
+namespace params = CGAL::parameters;
+
+typedef CGAL::Exact_predicates_exact_constructions_kernel             EPECK;
+typedef CGAL::Exact_predicates_inexact_constructions_kernel           EPICK;
+
+typedef CGAL::Polyhedron_3<EPECK, CGAL::Polyhedron_items_with_id_3>   Exact_polyhedron;
+typedef CGAL::Polyhedron_3<EPICK, CGAL::Polyhedron_items_with_id_3>   Polyhedron;
+typedef CGAL::Surface_mesh<EPICK::Point_3>                            Surface_mesh;
+
+template <typename Kernel, typename Mesh>
+void test()
+{
+  typedef typename Kernel::FT                                         FT;
+  typedef typename boost::graph_traits<Mesh>::vertex_descriptor       vertex_descriptor;
+
+  Mesh fg_source, fg_target;
+
+  // empty meshes
+  std::size_t res = PMP::internal::snap_border(fg_source, fg_target);
+  assert(res == 0);
+
+  std::ifstream source_input("data_snapping/border_snapping_source.off");
+  if(!source_input || !(source_input >> fg_source))
+  {
+    std::cerr << "Error: cannot open source mesh\n";
+    return;
+  }
+
+  // one empty mesh
+  res = PMP::internal::snap_border(fg_source, fg_target);
+  assert(res == 0);
+
+  res = PMP::internal::snap_border(fg_target, fg_source);
+  assert(res == 0);
+
+  std::ifstream target_input("data_snapping/border_snapping_target.off");
+  if(!target_input || !(target_input >> fg_target))
+  {
+    std::cerr << "Error: cannot open target mesh\n";
+    return;
+  }
+
+  Mesh fg_source_cpy = fg_source;
+
+  // this epsilon value is too small, nothing happens
+  std::cout << "*********************** EPS = 0.000000001 *************** " << std::endl;
+  res = PMP::internal::snap_border(fg_source_cpy, fg_target, 0.000000001);
+  std::cout << "Moved: " << res << " vertices" << std::endl;
+  assert(res == 0);
+
+  // this epsilon value is too big, and the snapping is rejected
+  std::cout << "*********************** EPS = 0.1 *************** " << std::endl;
+  fg_source_cpy = fg_source;
+  res = PMP::internal::snap_border(fg_source_cpy, fg_target,
+                                   params::geom_traits(Kernel()), params::all_default(), 0.1);
+  std::cout << "Moved: " << res << " vertices" << std::endl;
+  assert(res == 0);
+
+  // this is a good value of 'epsilon', but not all expected vertices are projected
+  // because the sampling of the border of the source mesh is not uniform
+  std::cout << "*********************** EPS = 0.001 *************** " << std::endl;
+  fg_source_cpy = fg_source;
+  CGAL::Constant_property_map<vertex_descriptor, FT> tol_map(0.001);
+  res = PMP::internal::snap_border(fg_source_cpy, fg_target,
+                                   params::tolerance_map(tol_map), params::all_default());
+  std::cout << "Moved: " << res << " vertices" << std::endl;
+  assert(res == 76);
+
+  std::ofstream partial_snap_out("partially_snapped_mesh.off");
+  partial_snap_out << std::setprecision(17) << fg_source_cpy;
+
+  // this one automatically computes an epsilon bound at each vertex
+  std::cout << "*********************** EPS = LOCALLY COMPUTED *************** " << std::endl;
+  fg_source_cpy = fg_source;
+  res = PMP::internal::snap_border(fg_source_cpy, fg_target);
+  std::cout << "Moved: " << res << " vertices" << std::endl;
+  assert(res == 77);
+
+  std::ofstream full_snap_out("snapped_mesh.off");
+  full_snap_out << std::setprecision(17) << fg_source_cpy;
+}
+
+int main(int, char**)
+{
+  std::cout << "TEST EPECK POLYHEDRON" << std::endl;
+  test<EPECK, Exact_polyhedron>();
+
+  std::cout << std::endl << "TEST EPICK POLYHEDRON" << std::endl;
+  test<EPICK, Polyhedron>();
+
+  std::cout << std::endl << "TEST EPICK SURFACE MESH" << std::endl;
+  test<EPICK, Surface_mesh>();
+
+  return EXIT_SUCCESS;
+}
+