added a region growing example with an extra paragraph in docs

Polygonal_surface_reconstruction/doc/Polygonal_surface_reconstruction/Polygonal_surface_reconstruction.txt

@@ -153,11 +153,14 @@ sharp edges in the final model.
 
 \subsection subsecExampleNoInputPlane Reconstruction from Point Clouds
 
-The method assumes that all necessary planes can be extracted from the input point set. The following example
+The method assumes that all necessary planes can be extracted from the input point set. The following examples
-first extracts planes from the input point cloud and then reconstructs the surface model.
+first extract planes from the input point cloud and then reconstruct the surface model. In the first example,
+the \ref Shape_detection_RANSAC "Efficient RANSAC approach" to extract planes is used. It is very fast,
+but not deterministic, oppose to the \ref Shape_detection_RegionGrowing "region growing approach" from the second example 
+that is slower, but more precise and always returns the same result for the same given parameters.
 
 \cgalExample{Polygonal_surface_reconstruction/polyfit_example_without_input_planes.cpp}
-
+\cgalExample{Polygonal_surface_reconstruction/polyfit_example_with_region_growing.cpp}
 
 
 
@@ -201,7 +204,7 @@ may result in an extremely large number of candidate faces, and thus a huge inte
 to be solved.
 
 The reconstruction time of a single object with moderate complexity is typically within a few seconds.
-Among the three steps, the face selection step deminates the reconstruction pipeline when the number
+Among the three steps, the face selection step dominates the reconstruction pipeline when the number
 of candidate faces is large (e.g., more than 5,000).
 
 

Polygonal_surface_reconstruction/doc/Polygonal_surface_reconstruction/dependencies

@@ -6,3 +6,4 @@ Alpha_shapes_2
 Surface_mesh
 Point_set_processing_3
 Solver_interface
+Shape_detection

Polygonal_surface_reconstruction/doc/Polygonal_surface_reconstruction/examples.txt

@@ -2,4 +2,5 @@
 \example Polygonal_surface_reconstruction/polyfit_example_without_input_planes.cpp
 \example Polygonal_surface_reconstruction/polyfit_example_user_provided_planes.cpp
 \example Polygonal_surface_reconstruction/polyfit_example_model_complexty_control.cpp
+\example Polygonal_surface_reconstruction/polyfit_example_with_region_growing.cpp
 */

Polygonal_surface_reconstruction/examples/Polygonal_surface_reconstruction/CMakeLists.txt

@@ -39,6 +39,7 @@ include( CGAL_CreateSingleSourceCGALProgram )
 create_single_source_cgal_program( "polyfit_example_without_input_planes.cpp" )
 create_single_source_cgal_program( "polyfit_example_user_provided_planes.cpp" )
 create_single_source_cgal_program( "polyfit_example_model_complexty_control.cpp" )
+create_single_source_cgal_program( "polyfit_example_with_region_growing.cpp" )
 
 find_package(Eigen3 3.1.0) #(requires 3.1.0 or greater)
 if(EIGEN3_FOUND)
@@ -63,6 +64,8 @@ if(EIGEN3_FOUND)
           target_compile_definitions(polyfit_example_user_provided_planes PRIVATE -DCGAL_USE_GLPK)
           target_link_libraries( polyfit_example_model_complexty_control PRIVATE ${GLPK_LIBRARIES} )
           target_compile_definitions(polyfit_example_model_complexty_control PRIVATE -DCGAL_USE_GLPK)
+          target_link_libraries( polyfit_example_with_region_growing PRIVATE ${GLPK_LIBRARIES} )
+          target_compile_definitions(polyfit_example_with_region_growing PRIVATE -DCGAL_USE_GLPK)
 
           message("GLPK found and used")
 
@@ -78,6 +81,8 @@ if(EIGEN3_FOUND)
       target_compile_definitions(polyfit_example_user_provided_planes PRIVATE -DCGAL_USE_SCIP)
       target_link_libraries( polyfit_example_model_complexty_control PRIVATE ${SCIP_LIBRARIES} )
       target_compile_definitions(polyfit_example_model_complexty_control PRIVATE -DCGAL_USE_SCIP)
+      target_link_libraries( polyfit_example_with_region_growing PRIVATE ${SCIP_LIBRARIES} )
+      target_compile_definitions(polyfit_example_with_region_growing PRIVATE -DCGAL_USE_SCIP)
 
       message("SCIP found and used")
 

Polygonal_surface_reconstruction/examples/Polygonal_surface_reconstruction/polyfit_example_with_region_growing.cpp

@@ -0,0 +1,199 @@
+#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
+#include <CGAL/IO/read_xyz_points.h>
+#include <CGAL/IO/Writer_OFF.h>
+#include <CGAL/property_map.h>
+#include <CGAL/Surface_mesh.h>
+#include <CGAL/Shape_detection/Region_growing/Region_growing.h>
+#include <CGAL/Shape_detection/Region_growing/Region_growing_on_point_set.h>
+#include <CGAL/Polygonal_surface_reconstruction.h>
+
+#ifdef CGAL_USE_SCIP
+
+#include <CGAL/SCIP_mixed_integer_program_traits.h>
+typedef CGAL::SCIP_mixed_integer_program_traits<double> MIP_Solver;
+
+#elif defined(CGAL_USE_GLPK)
+
+#include <CGAL/GLPK_mixed_integer_program_traits.h>
+typedef CGAL::GLPK_mixed_integer_program_traits<double>	MIP_Solver;
+
+#endif
+
+#if defined(CGAL_USE_GLPK) || defined(CGAL_USE_SCIP)
+
+#include <fstream>
+#include <CGAL/Timer.h>
+
+typedef CGAL::Exact_predicates_inexact_constructions_kernel	Kernel;
+
+typedef Kernel::FT       FT;
+typedef Kernel::Point_3	 Point;
+typedef Kernel::Vector_3 Vector;
+
+// Point with normal, and plane index.
+typedef boost::tuple<Point, Vector, int> PNI;
+typedef std::vector<PNI> Point_vector;
+
+typedef CGAL::Nth_of_tuple_property_map<0, PNI>	Point_map;
+typedef CGAL::Nth_of_tuple_property_map<1, PNI>	Normal_map;
+typedef CGAL::Nth_of_tuple_property_map<2, PNI>	Plane_index_map;
+
+typedef CGAL::Shape_detection::Point_set::
+Sphere_neighbor_query<Kernel, Point_vector, Point_map> Neighbor_query;
+typedef CGAL::Shape_detection::Point_set::
+Least_squares_plane_fit_region<Kernel, Point_vector, Point_map, Normal_map> Region_type;
+typedef CGAL::Shape_detection::
+Region_growing<Point_vector, Neighbor_query, Region_type> Region_growing;
+
+typedef CGAL::Surface_mesh<Point>	Surface_mesh;
+typedef	CGAL::Polygonal_surface_reconstruction<Kernel> Polygonal_surface_reconstruction;
+
+class Index_map {
+
+public:
+  using key_type = std::size_t;
+  using value_type = int;
+  using reference = value_type;
+  using category = boost::readable_property_map_tag;
+
+  Index_map() { }
+  template<typename PointRange>
+  Index_map(
+    const PointRange& points,
+    const std::vector< std::vector<std::size_t> >& regions) :
+  m_indices(new std::vector<int>(points.size(), -1)) {
+
+    for (std::size_t i = 0; i < regions.size(); ++i)
+      for (const std::size_t idx : regions[i])
+        (*m_indices)[idx] = static_cast<int>(i);
+  }
+
+  inline friend value_type get(
+    const Index_map& index_map,
+    const key_type key) {
+
+    const auto& indices = *(index_map.m_indices);
+    return indices[key];
+  }
+
+private:
+  std::shared_ptr< std::vector<int> > m_indices;
+};
+
+/*
+* This example first extracts planes from the input point cloud
+* (using region growing) and then reconstructs
+* the surface model from the planes.
+*/
+
+int main()
+{
+  Point_vector points;
+
+  // Load point set from a file.
+  const std::string input_file("data/cube.pwn");
+    std::ifstream input_stream(input_file.c_str());
+  if (input_stream.fail()) {
+    std::cerr << "Failed open file \'" << input_file << "\'" << std::endl;
+    return EXIT_FAILURE;
+  }
+  std::cout << "Loading point cloud: " << input_file << "...";
+
+  CGAL::Timer t;
+  t.start();
+    if (!input_stream ||
+    !CGAL::read_xyz_points(input_stream,
+      std::back_inserter(points),
+      CGAL::parameters::point_map(Point_map()).normal_map(Normal_map()))) {
+
+    std::cerr << "Error: cannot read file " << input_file << std::endl;
+    return EXIT_FAILURE;
+  }
+  else
+    std::cout << " Done. " << points.size() << " points. Time: "
+    << t.time() << " sec." << std::endl;
+
+  //////////////////////////////////////////////////////////////////////////
+
+  // Shape detection.
+
+  // Default parameter values for the data file cube.pwn.
+  const FT          search_sphere_radius  = FT(2) / FT(100);
+  const FT          max_distance_to_plane = FT(2) / FT(1000);
+  const FT          max_accepted_angle    = FT(25);
+  const std::size_t min_region_size       = 200;
+
+  // Create instances of the classes Neighbor_query and Region_type.
+  Neighbor_query neighbor_query(
+    points,
+    search_sphere_radius);
+
+  Region_type region_type(
+    points,
+    max_distance_to_plane, max_accepted_angle, min_region_size);
+
+  // Create an instance of the region growing class.
+  Region_growing region_growing(
+    points, neighbor_query, region_type);
+
+  std::cout << "Extracting planes...";
+  std::vector< std::vector<std::size_t> > regions;
+  t.reset();
+  region_growing.detect(std::back_inserter(regions));
+  std::cout << " Done. " << regions.size() << " planes extracted. Time: "
+  << t.time() << " sec." << std::endl;
+
+  // Stores the plane index of each point as the third element of the tuple.
+  Index_map index_map(points, regions);
+  for (std::size_t i = 0; i < points.size(); ++i) {
+    // Uses the get function from the property map that accesses the 3rd element of the tuple.
+    const int plane_index = get(index_map, i);
+    points[i].get<2>() = plane_index;
+  }
+
+  //////////////////////////////////////////////////////////////////////////
+
+  // Reconstruction.
+
+  std::cout << "Generating candidate faces...";
+  t.reset();
+  Polygonal_surface_reconstruction algo(
+    points,
+    Point_map(),
+    Normal_map(),
+    Plane_index_map()
+  );
+  std::cout << " Done. Time: " << t.time() << " sec." << std::endl;
+
+  Surface_mesh model;
+  std::cout << "Reconstructing...";
+  t.reset();
+  if (!algo.reconstruct<MIP_Solver>(model)) {
+    std::cerr << "Failed: " << algo.error_message() << std::endl;
+    return EXIT_FAILURE;
+  }
+  std::cout << " Done. Time: " << t.time() << " sec." << std::endl;
+
+  std::cout << "Saving...";
+  t.reset();
+  const std::string& output_file("data/cube_result.off");
+  std::ofstream output_stream(output_file.c_str());
+  if (output_stream && CGAL::write_off(output_stream, model))
+    std::cout << " Done. Saved to " << output_file << ". Time: " << t.time() << " sec." << std::endl;
+  else {
+    std::cerr << " Failed saving file." << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  return EXIT_SUCCESS;
+}
+
+#else
+
+int main(int, char**)
+{
+    std::cerr << "This test requires either GLPK or SCIP.\n";
+    return EXIT_SUCCESS;
+}
+
+#endif  // defined(CGAL_USE_GLPK) || defined(CGAL_USE_SCIP)