C++ Point_set::begin方法代码示例

  void compute_normals (Point_set& points, unsigned int neighbors)
  {
    CGAL::jet_estimate_normals<Concurrency_tag>(points.begin(), points.end(),
                                                CGAL::make_normal_of_point_with_normal_pmap(Point_set::value_type()),
                                                2 * neighbors);
    
    points.erase (CGAL::mst_orient_normals (points.begin(), points.end(),
					    CGAL::make_normal_of_point_with_normal_pmap(Point_set::value_type()),
					    2 * neighbors),
		  points.end ());
  }

  void advancing_front (const Point_set& points, Scene_polyhedron_item* new_item, double size)
  {
    Polyhedron& P = * const_cast<Polyhedron*>(new_item->polyhedron());
    Radius filter(10 * size);

    CGAL::advancing_front_surface_reconstruction (points.begin (), points.end (), P, filter);
						  
  }

  void advancing_front (const Point_set& points, Scene_polyhedron_item* new_item, double size,
                        double radius_ratio_bound = 5., double beta = 0.52)
  {
    Polyhedron& P = * const_cast<Polyhedron*>(new_item->polyhedron());
    Radius filter (size);

    CGAL::advancing_front_surface_reconstruction (points.begin (), points.end (), P, filter,
                                                  radius_ratio_bound, beta);
						  
  }

void print_point_set (const Point_set& point_set)
{
  std::cerr << "Content of point set:" << std::endl;
  for (Point_set::const_iterator it = point_set.begin();
       it != point_set.end(); ++ it)
    std::cerr << "* Point " << *it
              << ": " << point_set.point(*it) // or point_set[it]
              << " with normal " << point_set.normal(*it)
              << std::endl;
}

  void compute_normals (Point_set& points, unsigned int neighbors)
  {
    CGAL::jet_estimate_normals<Concurrency_tag>(points.begin_or_selection_begin(), points.end(),
                                                points.point_map(),
                                                points.normal_map(),
                                                2 * neighbors);

    points.set_first_selected (CGAL::mst_orient_normals (points.begin(), points.end(),
                                                         points.point_map(),
                                                         points.normal_map(),
                                                         2 * neighbors));
    points.delete_selection();
  }

  void scale_space (const Point_set& points, ItemsInserter items,
		    unsigned int scale, bool generate_smooth = false,
                    bool separate_shells = false, bool force_manifold = true,
                    unsigned int samples = 300, unsigned int iterations = 4)
  {
    ScaleSpace reconstruct (scale, samples);
    reconstruct.reconstruct_surface(points.begin (), points.end (), iterations,
                                    separate_shells, force_manifold);

    for( unsigned int sh = 0; sh < reconstruct.number_of_shells(); ++sh )
      {
        Scene_polygon_soup_item* new_item
          = new Scene_polygon_soup_item ();
        new_item->setColor(Qt::magenta);
        new_item->setRenderingMode(FlatPlusEdges);
        new_item->init_polygon_soup(points.size(), reconstruct.number_of_triangles ());

        Scene_polygon_soup_item* smooth_item = NULL;
        if (generate_smooth)
          {
            smooth_item = new Scene_polygon_soup_item ();
            smooth_item->setColor(Qt::magenta);
            smooth_item->setRenderingMode(FlatPlusEdges);
            smooth_item->init_polygon_soup(points.size(), reconstruct.number_of_triangles ());
          }

        std::map<unsigned int, unsigned int> map_i2i;
        unsigned int current_index = 0;
    
        for (ScaleSpace::Triple_iterator it = reconstruct.shell_begin (sh);
             it != reconstruct.shell_end (sh); ++ it)
          {
            for (unsigned int ind = 0; ind < 3; ++ ind)
              {
                if (map_i2i.find ((*it)[ind]) == map_i2i.end ())
                  {
                    map_i2i.insert (std::make_pair ((*it)[ind], current_index ++));
                    Point p = points[(*it)[ind]].position();
                    new_item->new_vertex (p.x (), p.y (), p.z ());
                    
                    if (generate_smooth)
                      {
                        p = *(reconstruct.points_begin() + (*it)[ind]);
                        smooth_item->new_vertex (p.x (), p.y (), p.z ());
                      }
                  }
              }
            new_item->new_triangle( map_i2i[(*it)[0]],
                                    map_i2i[(*it)[1]],
                                    map_i2i[(*it)[2]] );
            if (generate_smooth)
              smooth_item->new_triangle( map_i2i[(*it)[0]],
                                         map_i2i[(*it)[1]],
                                         map_i2i[(*it)[2]] );
              
          }

        *(items ++) = new_item;
        if (generate_smooth)
          *(items ++) = smooth_item;
      }

    if (force_manifold)
      {
        std::ptrdiff_t num = std::distance( reconstruct.garbage_begin(  ),
                                            reconstruct.garbage_end(  ) );

        Scene_polygon_soup_item* new_item
          = new Scene_polygon_soup_item ();
        new_item->setColor(Qt::blue);
        new_item->setRenderingMode(FlatPlusEdges);
        new_item->init_polygon_soup(points.size(), num);

        Scene_polygon_soup_item* smooth_item = NULL;
        if (generate_smooth)
          {
            smooth_item = new Scene_polygon_soup_item ();
            smooth_item->setColor(Qt::blue);
            smooth_item->setRenderingMode(FlatPlusEdges);
            smooth_item->init_polygon_soup(points.size(), num);
          }

        std::map<unsigned int, unsigned int> map_i2i;

        unsigned int current_index = 0;
        for (ScaleSpace::Triple_iterator it=reconstruct.garbage_begin(),
               end=reconstruct.garbage_end();it!=end;++it)
          {
            for (unsigned int ind = 0; ind < 3; ++ ind)
              {
                if (map_i2i.find ((*it)[ind]) == map_i2i.end ())
                  {
                    map_i2i.insert (std::make_pair ((*it)[ind], current_index ++));
                    Point p = points[(*it)[ind]].position();
                    new_item->new_vertex (p.x (), p.y (), p.z ());
                    
                    if (generate_smooth)
                      {
                        p = *(reconstruct.points_begin() + (*it)[ind]);
                        smooth_item->new_vertex (p.x (), p.y (), p.z ());
//.........这里部分代码省略.........

 void smooth_point_set (Point_set& points, unsigned int scale)
 {
   CGAL::jet_smooth_point_set<Concurrency_tag>(points.begin(), points.end(),
                                               scale);
 }

  void simplify_point_set (Point_set& points, double size)
  {
    points.erase (CGAL::grid_simplify_point_set (points.begin (), points.end (), size),
		  points.end ());
  }

  unsigned int scale_of_noise (const Point_set& points, double& size)
  {
    Tree tree(points.begin(), points.end());
    
    double ratio_kept = (points.size() < 1000)
      ? 1. : 1000. / (points.size());
    
    std::vector<Point> subset;
    for (std::size_t i = 0; i < points.size (); ++ i)
      if (rand() / (double)RAND_MAX < ratio_kept)
    	subset.push_back (points[i]);
    
    std::vector<unsigned int> scales;
    generate_scales (std::back_inserter (scales));

    std::vector<unsigned int> chosen;
    
    for (std::size_t i = 0; i < subset.size (); ++ i)
      {
    	Neighbor_search search(tree, subset[i],scales.back());
	double current = 0.;
    	unsigned int nb = 0;
    	std::size_t index = 0;
	double minimum = (std::numeric_limits<double>::max)();
	unsigned int c = 0;
	
    	for (Search_iterator search_iterator = search.begin();
    	     search_iterator != search.end (); ++ search_iterator, ++ nb)
    	  {
	    current += search_iterator->second;

    	    if (nb + 1 == scales[index])
    	      {
		double score = std::sqrt (current / scales[index])
		  / std::pow (scales[index], 0.375); // NB ^ (5/12)

		if (score < minimum)
		  {
		    minimum = score;
		    c = scales[index];
		  }

    		++ index;
    		if (index == scales.size ())
    		  break;
    	      }
    	  }
	chosen.push_back (c);
      }

    std::sort (chosen.begin (), chosen.end());

    unsigned int noise_scale = chosen[chosen.size() / 2];
    size = 0.;
    for (std::size_t i = 0; i < subset.size (); ++ i)
      {
    	Neighbor_search search(tree, subset[i], noise_scale);
	size += std::sqrt ((-- search.end())->second);
      }
    size /= subset.size();

    
    return noise_scale;
  }

  unsigned int scale_of_anisotropy (const Point_set& points, double& size)
  {
    Tree tree(points.begin(), points.end());
    
    double ratio_kept = (points.size() < 1000)
      ? 1. : 1000. / (points.size());
    
    std::vector<Point> subset;
    for (std::size_t i = 0; i < points.size (); ++ i)
      if (rand() / (double)RAND_MAX < ratio_kept)
    	subset.push_back (points[i]);
    
    std::vector<unsigned int> scales;
    generate_scales (std::back_inserter (scales));

    std::vector<unsigned int> chosen;

    for (std::size_t i = 0; i < subset.size (); ++ i)
      {
    	Neighbor_search search(tree, subset[i],scales.back());
	double current = 0.;
    	unsigned int nb = 0;
    	std::size_t index = 0;
	double maximum = 0.;
	unsigned int c = 0;
	
    	for (Search_iterator search_iterator = search.begin();
    	     search_iterator != search.end (); ++ search_iterator, ++ nb)
    	  {
	    current += search_iterator->second;

    	    if (nb + 1 == scales[index])
    	      {
		double score = std::sqrt (current / scales[index])
		  / std::pow (scales[index], 0.75); // NB ^ (3/4)

		if (score > maximum)
		  {
		    maximum = score;
		    c = scales[index];
		  }

    		++ index;
    		if (index == scales.size ())
    		  break;
    	      }
    	  }
	chosen.push_back (c);
      }

    double mean = 0.;
    for (std::size_t i = 0; i < chosen.size(); ++ i)
      mean += chosen[i];
    mean /= chosen.size();
    unsigned int aniso_scale = static_cast<unsigned int>(mean);

    size = 0.;
    for (std::size_t i = 0; i < subset.size (); ++ i)
      {
    	Neighbor_search search(tree, subset[i], aniso_scale);
	size += std::sqrt ((-- search.end())->second);
      }
    size /= subset.size();
    
    return aniso_scale;
  }

 void simplify_point_set (Point_set& points, double size)
 {
   points.set_first_selected (CGAL::grid_simplify_point_set (points.begin (), points.end (), points.point_map(), size));
   points.delete_selection();
 }