// Copyright (c) 2007-09  INRIA Sophia-Antipolis (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v5.6.1/Poisson_surface_reconstruction_3/include/CGAL/IO/output_surface_facets_to_triangle_soup.h $
// $Id: output_surface_facets_to_triangle_soup.h 47f0eb4 2022-05-26T19:06:01+02:00 albert-github
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
// Author(s) : Pierre Alliez

#ifndef CGAL_OUTPUT_SURFACE_FACETS_TO_TRIANGLE_SOUP_H
#define CGAL_OUTPUT_SURFACE_FACETS_TO_TRIANGLE_SOUP_H

#include <CGAL/license/Poisson_surface_reconstruction_3.h>


#include <CGAL/Polyhedron_3.h>
#include <CGAL/IO/Complex_2_in_triangulation_3_polyhedron_builder.h>
#include <CGAL/value_type_traits.h>

namespace CGAL {


/// Gets reconstructed surface out of a SurfaceMeshComplex_2InTriangulation_3 object.
///
/// This variant exports the surface as a triangle soup.
///
/// @tparam OutputIteratorValueType value_type of OutputIterator.
///        It is default to value_type_traits<OutputIterator>::type, and can be omitted when the default is fine.
/// @tparam SurfaceMeshComplex_2InTriangulation_3 model of the SurfaceMeshComplex_2InTriangulation_3 concept.
/// @tparam OutputIterator value_type must be convertible from Triangle_3<Kernel>.
template <typename OutputIteratorValueType,
          class SurfaceMeshComplex_2InTriangulation_3,
          typename OutputIterator>
void
output_surface_facets_to_triangle_soup(
  const SurfaceMeshComplex_2InTriangulation_3& c2t3, ///< Input surface.
  OutputIterator output_iterator) ///< Output iterator.
{
  typedef SurfaceMeshComplex_2InTriangulation_3 C2t3;
  typedef typename C2t3::Triangulation Tr;
  typedef typename Tr::Finite_facets_iterator Finite_facets_iterator;
  typedef typename Tr::Vertex_handle Vertex_handle;
  typedef typename Tr::Point Point;

  // value_type_traits is a workaround as back_insert_iterator's value_type is void
  // typedef typename value_type_traits<OutputIterator>::type Triangle;
  typedef OutputIteratorValueType Triangle;

  const Tr& tr = c2t3.triangulation();

  for(Finite_facets_iterator fit = tr.finite_facets_begin();
    fit != tr.finite_facets_end();
    ++fit)
  {
    if((*fit).first->is_facet_on_surface((*fit).second) == true)
    {
      std::vector<Point> points(3);
      unsigned int index = 0;
      for(int i=0; i<4; i++)
        if(i != (*fit).second)
          points[index++] = (*fit).first->vertex(i)->point();

      *output_iterator = Triangle(points[0],points[1],points[2]);
      output_iterator++;
    }
  }
}

template <class SurfaceMeshComplex_2InTriangulation_3,
          typename OutputIterator>
void
output_surface_facets_to_triangle_soup(
  const SurfaceMeshComplex_2InTriangulation_3& c2t3, ///< Input surface.
  OutputIterator output_iterator)
{
  output_surface_facets_to_triangle_soup
    <typename value_type_traits<OutputIterator>::type>
    (c2t3, output_iterator);
}

} //namespace CGAL

#endif // CGAL_OUTPUT_SURFACE_FACETS_TO_TRIANGLE_SOUP_H

