Point_set_processing_3/orient_scanlines_example.cpp

#include <CGAL/Simple_cartesian.h>
#include <CGAL/IO/read_las_points.h>
#include <CGAL/IO/write_ply_points.h>
#include <CGAL/jet_estimate_normals.h>
#include <CGAL/scanline_orient_normals.h>

using Kernel = CGAL::Simple_cartesian<double>;
using Point_3 = Kernel::Point_3;
using Vector_3 = Kernel::Vector_3;
using Point_with_info = std::tuple<Point_3, Vector_3, float, unsigned char>;
using Point_map = CGAL::Nth_of_tuple_property_map<0, Point_with_info>;
using Normal_map = CGAL::Nth_of_tuple_property_map<1, Point_with_info>;
using Scan_angle_map = CGAL::Nth_of_tuple_property_map<2, Point_with_info>;
using Scanline_id_map = CGAL::Nth_of_tuple_property_map<3, Point_with_info>;

void dump (const char* filename, const std::vector<Point_with_info>& points)
{
  std::ofstream ofile (filename, std::ios::binary);
  CGAL::set_binary_mode(ofile);
  CGAL::write_ply_points
    (ofile, points,
     CGAL::parameters::point_map (Point_map()).
     normal_map (Normal_map()));

}

int main (int argc, char** argv)
{
  std::string fname (argc > 1 ? argv[1] : "data/urban.las");

  std::vector<Point_with_info> points;

  std::cerr << "Reading input file " << fname << std::endl;
  std::ifstream ifile (fname, std::ios::binary);
  if (!ifile ||
      !CGAL::read_las_points_with_properties
      (ifile, std::back_inserter (points),
       CGAL::make_las_point_reader (Point_map()),
       std::make_pair (Scan_angle_map(),
                       CGAL::LAS_property::Scan_angle()),
       std::make_pair (Scanline_id_map(),
                       CGAL::LAS_property::Scan_direction_flag())))
  {
    std::cerr << "Can't read " << fname << std::endl;
    return EXIT_FAILURE;
  }


  std::cerr << "Estimating normals" << std::endl;
  CGAL::jet_estimate_normals<CGAL::Parallel_if_available_tag>
    (points, 12,
     CGAL::parameters::point_map (Point_map()).
     normal_map (Normal_map()));

  std::cerr << "Orienting normals using scan angle and direction flag" << std::endl;
  CGAL::scanline_orient_normals
    (points,
     CGAL::parameters::point_map (Point_map()).
     normal_map (Normal_map()).
     scan_angle_map (Scan_angle_map()).
     scanline_id_map (Scanline_id_map()));
  dump("out_angle_and_flag.ply", points);

  std::cerr << "Orienting normals using scan direction flag only" << std::endl;
  CGAL::scanline_orient_normals
    (points,
     CGAL::parameters::point_map (Point_map()).
     normal_map (Normal_map()).
     scanline_id_map (Scanline_id_map()));
  dump("out_flag.ply", points);

  std::cerr << "Orienting normals using scan angle only" << std::endl;
  CGAL::scanline_orient_normals
    (points,
     CGAL::parameters::point_map (Point_map()).
     normal_map (Normal_map()).
     scan_angle_map (Scan_angle_map()));
  dump("out_angle.ply", points);

  std::cerr << "Orienting normals using no additional info" << std::endl;
  CGAL::scanline_orient_normals
    (points,
     CGAL::parameters::point_map (Point_map()).
     normal_map (Normal_map()));
  dump("out_nothing.ply", points);

  return EXIT_SUCCESS;
}