Box_intersection_d/triangle_self_intersect_pointers.cpp

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/box_intersection_d.h>
#include <vector>
#include <fstream>

typedef CGAL::Exact_predicates_inexact_constructions_kernel   Kernel;
typedef Kernel::Point_3                                       Point_3;
typedef Kernel::Triangle_3                                    Triangle_3;
typedef std::vector<Triangle_3>                               Triangles;
typedef Triangles::iterator                                   Iterator;
typedef CGAL::Box_intersection_d::Box_with_handle_d<double,3,Iterator> Box;

struct Report {
  Triangles* triangles;

  Report(Triangles& triangles)
    : triangles(&triangles)
  {}

  // callback functor that reports all truly intersecting triangles
  void operator()(const Box* a, const Box* b) const
  {
    std::cout << "Box " << (a->handle() - triangles->begin()) << " and "
              << (b->handle() - triangles->begin()) << " intersect";
    if ( ! a->handle()->is_degenerate() && ! b->handle()->is_degenerate()
         && CGAL::do_intersect( *(a->handle()), *(b->handle()))) {
      std::cout << ", and the triangles intersect also";
    }
    std::cout << '.' << std::endl;
  }
};


int main(int argc, char*argv[])
{
  std::ifstream in((argc>1)?argv[1]:"data/triangles.xyz");
  Triangles triangles;
  Triangle_3 t;
  while(in >> t){
    triangles.push_back(t);
  }
  // Create the corresponding vector of bounding boxes
  std::vector<Box> boxes;
  for ( Iterator i = triangles.begin(); i != triangles.end(); ++i)
    boxes.push_back( Box( i->bbox(), i));
  
  // Create the corresponding vector of pointers to bounding boxes
  std::vector<Box *> ptr;
  for ( std::vector<Box>::iterator i = boxes.begin(); i != boxes.end(); ++i)
    ptr.push_back( &*i);
  
  // Run the self intersection algorithm with all defaults on the
  // indirect pointers to bounding boxes. Avoids copying the boxes.
  CGAL::box_self_intersection_d( ptr.begin(), ptr.end(), Report(triangles));
  return 0;
}