cgal/Triangulation_2/include/CGAL/mark_domain_in_triangulation.h

116 lines
3.0 KiB
C++

// Copyright (c) 2022 GeometryFactory (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL$
// $Id$
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
// Author(s) : Andreas Fabri
#ifndef CGAL_MARK_DOMAIN_IN_TRIANGULATION_H
#define CGAL_MARK_DOMAIN_IN_TRIANGULATION_H
#include <CGAL/license/Triangulation_2.h>
#include <CGAL/assertions.h>
#include <CGAL/Triangulation_2/internal/In_domain.h>
#include <CGAL/Unique_hash_map.h>
#include <boost/property_map/property_map.hpp>
#include <deque>
#include <list>
namespace CGAL {
namespace internal {
template <typename CT, typename InDomainPmap>
void
mark_domain_in_triangulation(CT& ct,
Unique_hash_map<typename CT::Face_handle,int>& nesting_level,
typename CT::Face_handle start,
int index,
std::list<typename CT::Edge>& border,
InDomainPmap ipm)
{
typedef typename CT::Face_handle Face_handle;
typedef typename CT::Edge Edge;
CGAL_precondition(ct.dimension() == 2);
if(nesting_level[start] != -1){
return;
}
std::list<Face_handle> queue;
queue.push_back(start);
while(! queue.empty()){
Face_handle fh = queue.front();
queue.pop_front();
if(nesting_level[fh] == -1){
nesting_level[fh] = index;
if(index %2 == 1){
put(ipm, fh, true);
}
for(int i = 0; i < 3; i++){
Edge e(fh,i);
Face_handle n = fh->neighbor(i);
if(nesting_level[n] == -1){
if(ct.is_constrained(e)) border.push_back(e);
else queue.push_back(n);
}
}
}
}
}
} // namespace internal
//explore set of facets connected with non constrained edges,
//and attribute to each such set a nesting level.
//We start from facets incident to the infinite vertex, with a nesting
//level of 0. Then we recursively consider the non-explored facets incident
//to constrained edges bounding the former set and increase the nesting level by 1.
//Facets in the domain are those with an odd nesting level.
template <typename CT, typename InDomainPmap>
void
mark_domain_in_triangulation(CT& cdt, InDomainPmap ipm)
{
typedef typename CT::Face_handle Face_handle;
typedef typename CT::Edge Edge;
Unique_hash_map<Face_handle,int> nesting_level(-1, cdt.number_of_faces());
for(Face_handle f : cdt.all_face_handles()){
put(ipm, f, false);
}
std::list<Edge> border;
internal::mark_domain_in_triangulation(cdt, nesting_level, cdt.infinite_face(), 0, border, ipm);
while(! border.empty()){
Edge e = border.front();
border.pop_front();
Face_handle n = e.first->neighbor(e.second);
if(nesting_level[n] == -1){
internal::mark_domain_in_triangulation(cdt, nesting_level, n, nesting_level[e.first]+1, border, ipm);
}
}
}
template <typename CT>
void
mark_domain_in_triangulation(CT& cdt)
{
internal::In_domain<CT> in_domain;
mark_domain_in_triangulation(cdt, in_domain);
}
} // namespace CGAL
#endif // CGAL_MARK_DOMAIN_IN_TRIANGULATION_H