Convex_decomposition_3/list_of_convex_parts.cpp

#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
#include <CGAL/Polyhedron_3.h>
#include <CGAL/Nef_polyhedron_3.h>
#include <CGAL/IO/Nef_polyhedron_iostream_3.h>
#include <CGAL/Nef_3/SNC_indexed_items.h>
#include <CGAL/convex_decomposition_3.h> 
#include <list>

typedef CGAL::Exact_predicates_exact_constructions_kernel Kernel;
typedef CGAL::Polyhedron_3<Kernel> Polyhedron_3;
typedef CGAL::Nef_polyhedron_3<Kernel, CGAL::SNC_indexed_items> Nef_polyhedron_3;
typedef Nef_polyhedron_3::Volume_const_iterator Volume_const_iterator;

int main() {
  
  Nef_polyhedron_3 N;
  std::cin >> N;

  CGAL::convex_decomposition_3(N);
  std::list<Polyhedron_3> convex_parts;
  
  // the first volume is the outer volume, which is 
  // ignored in the decomposition
  Volume_const_iterator ci = ++N.volumes_begin();
  for( ; ci != N.volumes_end(); ++ci) {
    if(ci->mark()) {
      Polyhedron_3 P;
      N.convert_inner_shell_to_polyhedron(ci->shells_begin(), P);
      convex_parts.push_back(P);
    }
  }
  std::cout << "decomposition into " << convex_parts.size() << " convex parts " << std::endl;

}