cgal/Operations_on_polyhedra/include/CGAL/triangulate_polyhedron.h

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// Copyright (c) 2010-2011 GeometryFactory Sarl (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
// You can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
//
//
// Author(s) : Laurent Rineau
#ifndef CGAL_TRIANGULATE_POLYHEDRON_H
#include <CGAL/Modifier_base.h>
#include <CGAL/HalfedgeDS_decorator.h>
#include <CGAL/Triangulation_vertex_base_with_info_2.h>
#include <CGAL/Triangulation_face_base_with_info_2.h>
#include <CGAL/Constrained_Delaunay_triangulation_2.h>
#include <CGAL/Constrained_triangulation_plus_2.h>
#include <CGAL/Triangulation_2_filtered_projection_traits_3.h>
#include <CGAL/internal/Operations_on_polyhedra/compute_normal.h>
#include <queue>
#include <vector>
#include <utility>
namespace CGAL {
template <class Polyhedron>
class Triangulate_modifier
: public CGAL::Modifier_base<typename Polyhedron::HalfedgeDS>
{
typedef typename Polyhedron::HalfedgeDS HDS;
typedef typename Polyhedron::Traits Traits;
typedef typename Polyhedron::Halfedge_handle Halfedge_handle;
typedef typename Polyhedron::Facet Facet;
typedef typename Polyhedron::Facet_iterator Facet_iterator;
typedef typename Polyhedron::Facet_handle Facet_handle;
typedef CGAL::Triangulation_2_filtered_projection_traits_3<Traits> P_traits;
typedef CGAL::Triangulation_vertex_base_with_info_2<Halfedge_handle,
P_traits> Vb;
struct Face_info {
typename Polyhedron::Halfedge_handle e[3];
bool is_external;
};
typedef CGAL::Triangulation_face_base_with_info_2<Face_info,
P_traits> Fb1;
typedef CGAL::Constrained_triangulation_face_base_2<P_traits, Fb1> Fb;
typedef CGAL::Triangulation_data_structure_2<Vb,Fb> TDS;
typedef CGAL::No_intersection_tag Itag;
typedef CGAL::Constrained_Delaunay_triangulation_2<P_traits,
TDS,
Itag> CDTbase;
typedef CGAL::Constrained_triangulation_plus_2<CDTbase> CDT;
public:
Triangulate_modifier()
{
}
bool is_external(typename CDT::Face_handle fh) const {
return fh->info().is_external;
}
void operator()(HDS& hds) {
CGAL::HalfedgeDS_decorator<HDS> decorator(hds);
typedef typename HDS::Halfedge Halfedge;
// One need to store facet handles into a vector, because the list of
// facets of the polyhedron will be modified during the loop, and
// that invalidates the range [facets_begin(), facets_end()[.
std::vector<Facet_handle> facets;
facets.reserve(hds.size_of_faces());
for(Facet_iterator
fit = hds.faces_begin(),
end = hds.faces_end();
fit != end; ++fit) {
facets.push_back(fit);
}
// Iterates on the vector of facet handles
for(typename std::vector<Facet_handle>::iterator
fit_it = facets.begin(),
end = facets.end();
fit_it != end; ++fit_it)
{
Facet_handle fit = *fit_it;
typename Traits::Vector_3 normal =
compute_facet_normal<Facet,Traits>(*fit);
P_traits cdt_traits(normal);
CDT cdt(cdt_traits);
typename Facet::Halfedge_around_facet_circulator
he_circ = fit->facet_begin(),
he_circ_end(he_circ);
typename CDT::Vertex_handle previous, first;
do {
typename CDT::Vertex_handle vh = cdt.insert(he_circ->vertex()->point());
if(first == 0) {
first = vh;
}
vh->info() = he_circ;
if(previous != 0 && previous != vh) {
cdt.insert_constraint(previous, vh);
}
previous = vh;
} while( ++he_circ != he_circ_end );
cdt.insert_constraint(previous, first);
// sets mark is_external
for(typename CDT::All_faces_iterator
fit = cdt.all_faces_begin(),
end = cdt.all_faces_end();
fit != end; ++fit)
{
fit->info().is_external = false;
}
std::queue<typename CDT::Face_handle> face_queue;
face_queue.push(cdt.infinite_vertex()->face());
while(! face_queue.empty() ) {
typename CDT::Face_handle fh = face_queue.front();
face_queue.pop();
if(fh->info().is_external) continue;
fh->info().is_external = true;
for(int i = 0; i <3; ++i) {
if(!cdt.is_constrained(std::make_pair(fh, i)))
{
face_queue.push(fh->neighbor(i));
}
}
}
// then modify the polyhedron
decorator.make_hole(fit->halfedge());
for(typename CDT::Finite_edges_iterator
eit = cdt.finite_edges_begin(),
end = cdt.finite_edges_end();
eit != end; ++eit)
{
typename CDT::Face_handle fh = eit->first;
const int index = eit->second;
typename CDT::Face_handle opposite_fh = fh->neighbor(eit->second);
const int opposite_index = opposite_fh->index(fh);
const typename CDT::Vertex_handle va = fh->vertex(cdt. cw(index));
const typename CDT::Vertex_handle vb = fh->vertex(cdt.ccw(index));
if( ! (is_external(fh) && is_external(opposite_fh)) &&
! cdt.is_constrained(*eit) )
{
// strictly internal edge
Halfedge_handle h = hds.edges_push_back(Halfedge(),
Halfedge());
fh->info().e[index] = h;
opposite_fh->info().e[opposite_index] = h->opposite();
decorator.set_vertex(h, va->info()->vertex());
decorator.set_vertex(h->opposite(), vb->info()->vertex());
}
if( cdt.is_constrained(*eit) )
{
if(!is_external(fh)) {
fh->info().e[index] = va->info();
}
if(!is_external(opposite_fh)) {
opposite_fh->info().e[opposite_index] = vb->info();
}
}
}
for(typename CDT::Finite_faces_iterator
fit = cdt.finite_faces_begin(),
end = cdt.finite_faces_end();
fit != end; ++fit)
{
if(!is_external(fit))
{
Halfedge_handle h0 = fit->info().e[0];
Halfedge_handle h1 = fit->info().e[1];
Halfedge_handle h2 = fit->info().e[2];
CGAL_assertion( h0 != Halfedge_handle() );
CGAL_assertion( h1 != Halfedge_handle() );
CGAL_assertion( h2 != Halfedge_handle() );
typedef typename Halfedge::Base HBase;
h0->HBase::set_next(h1);
decorator.set_prev(h1, h0);
h1->HBase::set_next(h2);
decorator.set_prev(h2, h1);
h2->HBase::set_next(h0);
decorator.set_prev(h0, h2);
decorator.fill_hole(h0);
}
}
} // end loop on facets of the input polyhedron
}
}; // end class Triangulate_modifier
template <typename Polyhedron>
void triangulate_polyhedron(Polyhedron& p)
{
CGAL::Triangulate_modifier<Polyhedron> modifier;
p.delegate(modifier);
}
} // end namespace CGAL
#endif // CGAL_TRIANGULATE_POLYHEDRON_H