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cgal/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/repair.h

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// Copyright (c) 2015 GeometryFactory (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) : Sebastien Loriot
#ifndef CGAL_POLYGON_MESH_PROCESSING_REPAIR_H
#define CGAL_POLYGON_MESH_PROCESSING_REPAIR_H
#include <CGAL/license/Polygon_mesh_processing/repair.h>
#include <set>
#include <vector>
#include <boost/algorithm/minmax_element.hpp>
#include <CGAL/boost/graph/Euler_operations.h>
#include <CGAL/Union_find.h>
#include <CGAL/algorithm.h>
// headers for self-intersection removal
#include <CGAL/Polygon_mesh_processing/self_intersections.h>
#include <CGAL/Polygon_mesh_processing/triangulate_hole.h>
#include <CGAL/boost/graph/selection.h>
#include <CGAL/Polygon_mesh_processing/internal/named_function_params.h>
#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
#ifdef CGAL_PMP_REMOVE_DEGENERATE_FACES_DEBUG
#include <CGAL/Polygon_mesh_processing/polygon_soup_to_polygon_mesh.h>
#include <CGAL/IO/OFF_reader.h>
#include <iostream>
#include <fstream>
#endif
namespace CGAL{
namespace Polygon_mesh_processing {
namespace debug{
template <class TriangleMesh, class VertexPointMap>
std::ostream& dump_edge_neighborhood(
typename boost::graph_traits<TriangleMesh>::edge_descriptor ed,
TriangleMesh& tmesh,
const VertexPointMap& vpmap,
std::ostream& out)
{
typedef boost::graph_traits<TriangleMesh> GT;
typedef typename GT::halfedge_descriptor halfedge_descriptor;
typedef typename GT::vertex_descriptor vertex_descriptor;
typedef typename GT::face_descriptor face_descriptor;
halfedge_descriptor h = halfedge(ed, tmesh);
std::map<vertex_descriptor, int> vertices;
std::set<face_descriptor> faces;
int vindex=0;
BOOST_FOREACH(halfedge_descriptor hd, halfedges_around_target(h, tmesh))
{
if ( vertices.insert(std::make_pair(source(hd, tmesh), vindex)).second )
++vindex;
if (!is_border(hd, tmesh))
faces.insert( face(hd, tmesh) );
}
h=opposite(h, tmesh);
BOOST_FOREACH(halfedge_descriptor hd, halfedges_around_target(h, tmesh))
{
if ( vertices.insert(std::make_pair(source(hd, tmesh), vindex)).second )
++vindex;
if (!is_border(hd, tmesh))
faces.insert( face(hd, tmesh) );
}
std::vector<vertex_descriptor> ordered_vertices(vertices.size());
typedef std::pair<const vertex_descriptor, int> Pair_type;
BOOST_FOREACH(const Pair_type& p, vertices)
ordered_vertices[p.second]=p.first;
out << "OFF\n" << ordered_vertices.size() << " " << faces.size() << " 0\n";
BOOST_FOREACH(vertex_descriptor vd, ordered_vertices)
out << get(vpmap, vd) << "\n";
BOOST_FOREACH(face_descriptor fd, faces)
{
out << "3";
h=halfedge(fd,tmesh);
BOOST_FOREACH(halfedge_descriptor hd, halfedges_around_face(h, tmesh))
out << " " << vertices[target(hd, tmesh)];
out << "\n";
}
return out;
}
} //end of namespace debug
template <class HalfedgeGraph, class VertexPointMap, class Traits>
struct Less_vertex_point{
typedef typename boost::graph_traits<HalfedgeGraph>::vertex_descriptor vertex_descriptor;
const Traits& m_traits;
const VertexPointMap& m_vpmap;
Less_vertex_point(const Traits& traits, const VertexPointMap& vpmap)
: m_traits(traits)
, m_vpmap(vpmap) {}
bool operator()(vertex_descriptor v1, vertex_descriptor v2) const{
return m_traits.less_xyz_3_object()(get(m_vpmap, v1), get(m_vpmap, v2));
}
};
template <class Traits>
struct Less_along_ray{
const Traits& m_traits;
typename Traits::Point_3 m_source;
Less_along_ray(const Traits& traits,
const typename Traits::Point_3& s)
: m_traits(traits)
, m_source(s)
{};
bool operator()( const typename Traits::Point_3& p1,
const typename Traits::Point_3& p2) const
{
return m_traits.collinear_are_ordered_along_line_3_object()(m_source, p1, p2);
}
};
///\cond SKIP_IN_MANUAL
template <class Traits, class TriangleMesh, class VertexPointMap, class OutputIterator>
OutputIterator
degenerate_faces(const TriangleMesh& tm,
const VertexPointMap& vpmap,
const Traits& traits,
OutputIterator out)
{
typedef typename boost::graph_traits<TriangleMesh>::face_descriptor face_descriptor;
BOOST_FOREACH(face_descriptor fd, faces(tm))
{
if ( is_degenerate_triangle_face(fd, tm, vpmap, traits) )
*out++=fd;
}
return out;
}
template <class TriangleMesh, class OutputIterator>
OutputIterator
degenerate_faces(const TriangleMesh& tm, OutputIterator out)
{
typedef typename boost::property_map<TriangleMesh, CGAL::vertex_point_t>::type Vpm;
typedef typename boost::property_traits<Vpm>::value_type Point;
typedef typename Kernel_traits<Point>::Kernel Kernel;
return degenerate_faces(tm, get(vertex_point, tm), Kernel(), out);
}
// this function remove a border edge even if it does not satisfy the link condition.
// The only limitation is that the length connected component of the boundary this edge
// is strictly greater than 3
template <class TriangleMesh>
typename boost::graph_traits<TriangleMesh>::vertex_descriptor
remove_a_border_edge(typename boost::graph_traits<TriangleMesh>::edge_descriptor ed,
TriangleMesh& tm)
{
typedef boost::graph_traits<TriangleMesh> GT;
typedef typename GT::edge_descriptor edge_descriptor;
typedef typename GT::halfedge_descriptor halfedge_descriptor;
typedef typename GT::face_descriptor face_descriptor;
typedef typename GT::vertex_descriptor vertex_descriptor;
halfedge_descriptor h=halfedge(ed,tm);
if ( is_border(h,tm) )
h=opposite(h,tm);
halfedge_descriptor opp_h = opposite(h,tm);
CGAL_assertion(is_border(opp_h,tm));
CGAL_assertion(!is_border(h,tm));
CGAL_assertion(next(next(opp_h, tm), tm) !=opp_h); // not working for a hole made of 2 edges
CGAL_assertion(next(next(next(opp_h, tm), tm), tm) !=opp_h); // not working for a hole make of 3 edges
if (CGAL::Euler::does_satisfy_link_condition(edge(h,tm),tm))
return CGAL::Euler::collapse_edge(ed, tm);
// collect edges that have one vertex in the link of
// the vertices of h and one of the vertex of h as other vertex
std::set<edge_descriptor> common_incident_edges;
BOOST_FOREACH(halfedge_descriptor hos, halfedges_around_source(h, tm))
BOOST_FOREACH(halfedge_descriptor hot, halfedges_around_target(h, tm))
{
if( target(hos, tm) == source(hot, tm) )
{
common_incident_edges.insert( edge(hot, tm) );
common_incident_edges.insert( edge(hos, tm) );
}
}
// in the following loop, we visit define a connected component of
// faces bounded by edges in common_incident_edges and h. We look
// for the maximal one. This set of faces is the one that will
// disappear while collapsing ed
std::set<face_descriptor> marked_faces;
std::vector<halfedge_descriptor> queue;
queue.push_back( opposite(next(h,tm), tm) );
queue.push_back( opposite(prev(h,tm), tm) );
marked_faces.insert( face(h, tm) );
do{
std::vector<halfedge_descriptor> boundary;
while(!queue.empty())
{
halfedge_descriptor back=queue.back();
queue.pop_back();
face_descriptor fback=face(back,tm);
if (common_incident_edges.count(edge(back,tm)))
{
boundary.push_back(back);
continue;
}
if ( !marked_faces.insert(fback).second )
continue;
queue.push_back( opposite(next(back,tm), tm) );
queue.push_back( opposite(prev(back,tm), tm) );
}
CGAL_assertion( boundary.size() == 2 );
common_incident_edges.erase( edge(boundary[0], tm) );
common_incident_edges.erase( edge(boundary[1], tm) );
queue.push_back(boundary[0]);
queue.push_back(boundary[1]);
}
while(!common_incident_edges.empty());
// hk1 and hk2 are bounding the region that will be removed.
// The edge of hk2 will be removed and hk2 will be replaced
// by the opposite edge of hk1
halfedge_descriptor hk1=queue.front();
halfedge_descriptor hk2=queue.back();
if ( target(hk1,tm)!=source(hk2,tm) )
std::swap(hk1, hk2);
CGAL_assertion( target(hk1,tm)==source(hk2,tm) );
CGAL_assertion( source(hk1,tm)==source(h,tm) );
CGAL_assertion( target(hk2,tm)==target(h,tm) );
// collect vertices and edges to remove and do remove faces
std::set<edge_descriptor> edges_to_remove;
std::set<vertex_descriptor> vertices_to_remove;
BOOST_FOREACH(face_descriptor fd, marked_faces)
{
halfedge_descriptor hd=halfedge(fd, tm);
for(int i=0; i<3; ++i)
{
edges_to_remove.insert( edge(hd, tm) );
vertices_to_remove.insert( target(hd,tm) );
hd=next(hd, tm);
}
}
vertex_descriptor vkept=source(hk1,tm);
//back-up next, prev halfedge to be restore pointers after removal
halfedge_descriptor hp=prev(opp_h, tm);
halfedge_descriptor hn=next(opp_h, tm);
halfedge_descriptor hk1_opp_next = next(hk2, tm);
halfedge_descriptor hk1_opp_prev = prev(hk2, tm);
face_descriptor hk1_opp_face = face(hk2,tm);
// we will remove the target of hk2, update vertex pointers
BOOST_FOREACH(halfedge_descriptor hot,
halfedges_around_target(hk2, tm))
{
set_target(hot, vkept, tm);
}
// update halfedge pointers since hk2 will be removed
set_halfedge(vkept, opposite(hk1, tm), tm);
set_halfedge(target(hk1,tm), hk1, tm);
// do not remove hk1 and its vertices
vertices_to_remove.erase( vkept );
vertices_to_remove.erase( target(hk1, tm) );
edges_to_remove.erase( edge(hk1,tm) );
bool hk2_equals_hp = hk2==hp;
CGAL_assertion( is_border(hk2, tm) == hk2_equals_hp );
/*
- case hk2!=hp
/\ /
hk1/ \hk2 /
/ \ /
____/______\/____
hn h_opp hp
- case hk2==hp
/\
hk1/ \hk2 == hp
/ \
____/______\
hn h_opp
*/
// remove vertices
BOOST_FOREACH(vertex_descriptor vd, vertices_to_remove)
remove_vertex(vd, tm);
// remove edges
BOOST_FOREACH(edge_descriptor ed, edges_to_remove)
remove_edge(ed, tm);
// remove faces
BOOST_FOREACH(face_descriptor fd, marked_faces)
remove_face(fd, tm);
// now update pointers
set_face(opposite(hk1, tm), hk1_opp_face, tm);
if (!hk2_equals_hp)
{
set_next(hp, hn, tm);
set_next(opposite(hk1, tm), hk1_opp_next, tm);
set_next(hk1_opp_prev, opposite(hk1, tm), tm);
set_halfedge(hk1_opp_face, opposite(hk1, tm), tm);
}
else
{
set_next(hk1_opp_prev, opposite(hk1, tm), tm);
set_next(opposite(hk1, tm), hn, tm);
}
return vkept;
}
template <class EdgeRange, class TriangleMesh, class NamedParameters>
std::size_t remove_null_edges(
const EdgeRange& edge_range,
TriangleMesh& tmesh,
const NamedParameters& np)
{
CGAL_assertion(CGAL::is_triangle_mesh(tmesh));
using boost::get_param;
using boost::choose_param;
typedef TriangleMesh TM;
typedef typename boost::graph_traits<TriangleMesh> GT;
typedef typename GT::edge_descriptor edge_descriptor;
typedef typename GT::halfedge_descriptor halfedge_descriptor;
typedef typename GT::face_descriptor face_descriptor;
typedef typename GT::vertex_descriptor vertex_descriptor;
typedef typename GetVertexPointMap<TM, NamedParameters>::type VertexPointMap;
VertexPointMap vpmap = choose_param(get_param(np, internal_np::vertex_point),
get_property_map(vertex_point, tmesh));
typedef typename GetGeomTraits<TM, NamedParameters>::type Traits;
Traits traits = choose_param(get_param(np, internal_np::geom_traits), Traits());
std::size_t nb_deg_faces = 0;
// collect edges of length 0
std::set<edge_descriptor> null_edges_to_remove;
BOOST_FOREACH(edge_descriptor ed, edge_range)
{
if ( traits.equal_3_object()(get(vpmap, target(ed, tmesh)), get(vpmap, source(ed, tmesh))) )
null_edges_to_remove.insert(ed);
}
#ifdef CGAL_PMP_REMOVE_DEGENERATE_FACES_DEBUG
std::cout << "Found " << null_edges_to_remove.size() << " null edges.\n";
#endif
while (!null_edges_to_remove.empty())
{
edge_descriptor ed = *null_edges_to_remove.begin();
null_edges_to_remove.erase(null_edges_to_remove.begin());
halfedge_descriptor h = halfedge(ed, tmesh);
if (CGAL::Euler::does_satisfy_link_condition(ed,tmesh))
{
// remove edges that could also be set for removal
if ( face(h, tmesh)!=GT::null_face() )
{
++nb_deg_faces;
null_edges_to_remove.erase(edge(prev(h, tmesh), tmesh));
}
if (face(opposite(h, tmesh), tmesh)!=GT::null_face())
{
++nb_deg_faces;
null_edges_to_remove.erase(edge(prev(opposite(h, tmesh), tmesh), tmesh));
}
//now remove the edge
CGAL::Euler::collapse_edge(ed, tmesh);
}
else{
//handle the case when the edge is incident to a triangle hole
//we first fill the hole and try again
if ( is_border(ed, tmesh) )
{
halfedge_descriptor hd = halfedge(ed,tmesh);
if (!is_border(hd,tmesh)) hd=opposite(hd,tmesh);
if (is_triangle(hd, tmesh))
{
Euler::fill_hole(hd, tmesh);
null_edges_to_remove.insert(ed);
continue;
}
}
// When the edge does not satisfy the link condition, it means that it cannot be
// collapsed as is. In the following we assume that there is no topological issue
// with contracting the edge (no volume will disappear).
// We start by marking the faces that are incident to an edge endpoint.
// If the set of marked faces is a topologically disk, then we simply remove all the simplicies
// inside the disk and star the hole with the edge vertex kept.
// If the set of marked faces is not a topological disk, it has some non-manifold vertices
// on its boundary. We need to mark additional faces to make it a topological disk.
// We can then apply the star hole procedure.
// Right now we additionally mark the smallest connected components of non-marked faces
// (using the numnber of faces)
//backup central point
typename Traits::Point_3 pt = get(vpmap, source(ed, tmesh));
// mark faces of the link of each endpoints of the edge which collapse is not topologically valid
std::set<face_descriptor> marked_faces;
// first endpoint
BOOST_FOREACH( halfedge_descriptor hd, CGAL::halfedges_around_target(halfedge(ed,tmesh), tmesh) )
if (!is_border(hd,tmesh)) marked_faces.insert( face(hd, tmesh) );
// second endpoint
BOOST_FOREACH( halfedge_descriptor hd, CGAL::halfedges_around_target(opposite(halfedge(ed, tmesh), tmesh), tmesh) )
if (!is_border(hd,tmesh)) marked_faces.insert( face(hd, tmesh) );
// extract the halfedges on the boundary of the marked region
std::vector<halfedge_descriptor> border;
BOOST_FOREACH(face_descriptor fd, marked_faces)
BOOST_FOREACH(halfedge_descriptor hd, CGAL::halfedges_around_face(halfedge(fd,tmesh), tmesh))
{
halfedge_descriptor hd_opp = opposite(hd, tmesh);
if ( is_border(hd_opp, tmesh) ||
marked_faces.count( face(hd, tmesh) )!=
marked_faces.count( face(hd_opp, tmesh) ) )
{
border.push_back( hd );
}
}
CGAL_assertion( !border.empty() ); // a whole connected component got selected and will disappear (not handled for now)
// define cc of border halfedges: two halfedges are in the same cc
// if they are on the border of the cc of non-marked faces.
typedef CGAL::Union_find<halfedge_descriptor> UF_ds;
UF_ds uf;
std::map<halfedge_descriptor, typename UF_ds::handle> handles;
// one cc per border halfedge
BOOST_FOREACH(halfedge_descriptor hd, border)
handles.insert( std::make_pair(hd, uf.make_set(hd)) );
// join cc's
BOOST_FOREACH(halfedge_descriptor hd, border)
{
CGAL_assertion( marked_faces.count( face( hd, tmesh) ) > 0);
CGAL_assertion( marked_faces.count( face( opposite(hd, tmesh), tmesh) ) == 0 );
halfedge_descriptor candidate = hd;
do{
candidate = prev( opposite(candidate, tmesh), tmesh );
} while( !marked_faces.count( face( opposite(candidate, tmesh), tmesh) ) );
uf.unify_sets( handles[hd], handles[opposite(candidate, tmesh)] );
}
std::size_t nb_cc = uf.number_of_sets();
if ( nb_cc != 1 )
{
// if more than one connected component is found then the patch
// made of marked faces contains "non-manifold" vertices.
// The smallest components need to be marked so that the patch
// made of marked faces is a topological disk
// we will explore in parallel the connected components and will stop
// when all but one connected component have been entirely explored.
// We add one face at a time for each cc in order to not explore a
// potentially very large cc.
std::vector< std::vector<halfedge_descriptor> > stacks_per_cc(nb_cc);
std::vector< std::set<face_descriptor> > faces_per_cc(nb_cc);
std::vector< bool > exploration_finished(nb_cc, false);
// init the stacks of halfedges using the cc of the boundary
std::size_t index=0;
std::map< halfedge_descriptor, std::size_t > ccs;
typedef std::pair<const halfedge_descriptor, typename UF_ds::handle> Pair_type;
BOOST_FOREACH(Pair_type p, handles)
{
halfedge_descriptor opp_hedge = opposite(p.first, tmesh);
if (is_border(opp_hedge, tmesh)) continue; // nothing to do on the boundary
typedef typename std::map< halfedge_descriptor, std::size_t >::iterator Map_it;
std::pair<Map_it, bool> insert_res=
ccs.insert( std::make_pair(*uf.find( p.second ), index) );
if (insert_res.second) ++index;
stacks_per_cc[ insert_res.first->second ].push_back( prev(opp_hedge, tmesh) );
stacks_per_cc[ insert_res.first->second ].push_back( next(opp_hedge, tmesh) );
faces_per_cc[ insert_res.first->second ].insert( face(opp_hedge, tmesh) );
}
std::size_t nb_ccs_to_be_explored = nb_cc;
index=0;
//explore the cc's
do{
// try to extract one more face for a given cc
do{
CGAL_assertion( !exploration_finished[index] );
halfedge_descriptor hd = stacks_per_cc[index].back();
stacks_per_cc[index].pop_back();
hd = opposite(hd, tmesh);
if ( !is_border(hd,tmesh) && !marked_faces.count(face(hd, tmesh) ) )
{
if ( faces_per_cc[index].insert( face(hd, tmesh) ).second )
{
stacks_per_cc[index].push_back( next(hd, tmesh) );
stacks_per_cc[index].push_back( prev(hd, tmesh) );
break;
}
}
if (stacks_per_cc[index].empty()) break;
}
while(true);
// the exploration of a cc is finished when its stack is empty
exploration_finished[index]=stacks_per_cc[index].empty();
if ( exploration_finished[index] ) --nb_ccs_to_be_explored;
if ( nb_ccs_to_be_explored==1 ) break;
while ( exploration_finished[(++index)%nb_cc] );
index=index%nb_cc;
}while(true);
/// \todo use the area criteria? this means maybe continue exploration of larger cc
// mark faces of completetly explored cc
for (index=0; index< nb_cc; ++index)
if( exploration_finished[index] )
{
BOOST_FOREACH(face_descriptor fd, faces_per_cc[index])
marked_faces.insert(fd);
}
}
// collect simplices to be removed
std::set<vertex_descriptor> vertices_to_keep;
std::set<halfedge_descriptor> halfedges_to_keep;
BOOST_FOREACH(halfedge_descriptor hd, border)
if ( !marked_faces.count(face(opposite(hd, tmesh), tmesh)) )
{
halfedges_to_keep.insert( hd );
vertices_to_keep.insert( target(hd, tmesh) );
}
// backup next,prev relationships to set after patch removal
std::vector< std::pair<halfedge_descriptor, halfedge_descriptor> > next_prev_halfedge_pairs;
halfedge_descriptor first_border_hd=*( halfedges_to_keep.begin() );
halfedge_descriptor current_border_hd=first_border_hd;
do{
halfedge_descriptor prev_border_hd=current_border_hd;
current_border_hd=next(current_border_hd, tmesh);
while( marked_faces.count( face( opposite(current_border_hd, tmesh), tmesh) ) )
current_border_hd=next(opposite(current_border_hd, tmesh), tmesh);
next_prev_halfedge_pairs.push_back( std::make_pair(prev_border_hd, current_border_hd) );
}while(current_border_hd!=first_border_hd);
// collect vertices and edges to remove and do remove faces
std::set<edge_descriptor> edges_to_remove;
std::set<vertex_descriptor> vertices_to_remove;
BOOST_FOREACH(face_descriptor fd, marked_faces)
{
halfedge_descriptor hd=halfedge(fd, tmesh);
for(int i=0; i<3; ++i)
{
if ( !halfedges_to_keep.count(hd) )
edges_to_remove.insert( edge(hd, tmesh) );
if ( !vertices_to_keep.count(target(hd,tmesh)) )
vertices_to_remove.insert( target(hd,tmesh) );
hd=next(hd, tmesh);
}
remove_face(fd, tmesh);
}
// remove vertices
BOOST_FOREACH(vertex_descriptor vd, vertices_to_remove)
remove_vertex(vd, tmesh);
// remove edges
BOOST_FOREACH(edge_descriptor ed, edges_to_remove)
{
null_edges_to_remove.erase(ed);
remove_edge(ed, tmesh);
}
// add a new face, set all border edges pointing to it
// and update halfedge vertex of patch boundary vertices
face_descriptor new_face = add_face(tmesh);
typedef std::pair<halfedge_descriptor, halfedge_descriptor> Pair_type;
BOOST_FOREACH(const Pair_type& p, next_prev_halfedge_pairs)
{
set_face(p.first, new_face, tmesh);
set_next(p.first, p.second, tmesh);
set_halfedge(target(p.first, tmesh), p.first, tmesh);
}
set_halfedge(new_face, first_border_hd, tmesh);
// triangulate the new face and update the coordinate of the central vertex
halfedge_descriptor new_hd=Euler::add_center_vertex(first_border_hd, tmesh);
put(vpmap, target(new_hd, tmesh), pt);
BOOST_FOREACH(halfedge_descriptor hd, halfedges_around_target(new_hd, tmesh))
if ( traits.equal_3_object()(get(vpmap, target(hd, tmesh)), get(vpmap, source(hd, tmesh))) )
null_edges_to_remove.insert(edge(hd, tmesh));
CGAL_assertion( is_valid(tmesh) );
}
}
return nb_deg_faces;
}
template <class EdgeRange, class TriangleMesh>
std::size_t remove_null_edges(
const EdgeRange& edge_range,
TriangleMesh& tmesh)
{
return remove_null_edges(edge_range, tmesh,
parameters::all_default());
}
/// \ingroup PMP_repairing_grp
/// removes the degenerate faces from a triangulated surface mesh.
/// A face is considered degenerate if two of its vertices share the same location,
/// or more generally if all its vertices are collinear.
///
/// @pre `CGAL::is_triangle_mesh(tmesh)`
///
/// @tparam TriangleMesh a model of `FaceListGraph` and `MutableFaceGraph`
/// @tparam NamedParameters a sequence of \ref namedparameters
///
/// @param tmesh the triangulated surface mesh to be repaired
/// @param np optional \ref namedparameters described below
///
/// \cgalNamedParamsBegin
/// \cgalParamBegin{vertex_point_map} the property map with the points associated to the vertices of `pmesh`. The type of this map is model of `ReadWritePropertyMap`.
/// If this parameter is omitted, an internal property map for
/// `CGAL::vertex_point_t` should be available in `TriangleMesh`
/// \cgalParamEnd
/// \cgalParamBegin{geom_traits} a geometric traits class instance.
/// The traits class must provide the nested type `Point_3`,
/// and the nested functors :
/// - `Compare_distance_3` to compute the distance between 2 points
/// - `Collinear_are_ordered_along_line_3` to check whether 3 collinear points are ordered
/// - `Collinear_3` to check whether 3 points are collinear
/// - `Less_xyz_3` to compare lexicographically two points
/// - `Equal_3` to check whether 2 points are identical
/// - for each functor Foo, a function `Foo foo_object()`
/// \cgalParamEnd
/// \cgalNamedParamsEnd
///
/// \todo the function might not be able to remove all degenerate faces.
/// We should probably do something with the return type.
/// \return number of removed degenerate faces
template <class TriangleMesh, class NamedParameters>
std::size_t remove_degenerate_faces(TriangleMesh& tmesh,
const NamedParameters& np)
{
CGAL_assertion(CGAL::is_triangle_mesh(tmesh));
using boost::get_param;
using boost::choose_param;
typedef TriangleMesh TM;
typedef typename boost::graph_traits<TriangleMesh> GT;
typedef typename GT::edge_descriptor edge_descriptor;
typedef typename GT::halfedge_descriptor halfedge_descriptor;
typedef typename GT::face_descriptor face_descriptor;
typedef typename GT::vertex_descriptor vertex_descriptor;
typedef typename GetVertexPointMap<TM, NamedParameters>::type VertexPointMap;
VertexPointMap vpmap = choose_param(get_param(np, internal_np::vertex_point),
get_property_map(vertex_point, tmesh));
typedef typename GetGeomTraits<TM, NamedParameters>::type Traits;
Traits traits = choose_param(get_param(np, internal_np::geom_traits), Traits());
// First remove edges of length 0
std::size_t nb_deg_faces = remove_null_edges(edges(tmesh), tmesh, np);
#ifdef CGAL_PMP_REMOVE_DEGENERATE_FACES_DEBUG
{
std::cout <<"Done with null edges.\n";
std::ofstream output("/tmp/no_null_edges.off");
output << std::setprecision(17) << tmesh << "\n";
output.close();
}
#endif
// Then, remove triangles made of 3 collinear points
std::set<face_descriptor> degenerate_face_set;
BOOST_FOREACH(face_descriptor fd, faces(tmesh))
if ( is_degenerate_triangle_face(fd, tmesh, vpmap, traits) )
degenerate_face_set.insert(fd);
nb_deg_faces+=degenerate_face_set.size();
// first remove degree 3 vertices that are part of a cap
// (only the vertex in the middle of the opposite edge)
// This removal does not change the shape of the mesh.
if (!degenerate_face_set.empty())
{
std::set<vertex_descriptor> vertices_to_remove;
typename std::set<face_descriptor>::iterator fit=degenerate_face_set.begin();
while(fit!=degenerate_face_set.end())
{
halfedge_descriptor hd=halfedge(*fit, tmesh);
const typename Traits::Point_3& p1 = get(vpmap, target(hd, tmesh) );
const typename Traits::Point_3& p2 = get(vpmap, target(next(hd, tmesh), tmesh) );
const typename Traits::Point_3& p3 = get(vpmap, source(hd, tmesh) );
CGAL_assertion(p1!=p2 && p1!=p3 && p2!=p3);
typename Traits::Compare_distance_3 compare_distance = traits.compare_distance_3_object();
vertex_descriptor vd = boost::graph_traits<TriangleMesh>::null_vertex();
if (compare_distance(p1,p2, p1,p3) != CGAL::SMALLER) // p1p2 > p1p3
{
if (compare_distance(p1,p2, p2,p3) != CGAL::SMALLER) // p1p2 > p2p3
// p1p2 is the longest edge, pick p3
vd = source(hd, tmesh);
else
// p2p3 is the longest edge, pick p1
vd = target(hd, tmesh);
}
else
if (compare_distance(p1,p3, p2,p3) != CGAL::SMALLER) // p1p3>p2p3
// p1p3 is the longest edge, pick p2
vd = target(next(hd, tmesh), tmesh);
else
// p2p3 is the longest edge, pick p1
vd = target(hd, tmesh);
if (degree(vd, tmesh) == 3)
vertices_to_remove.insert(vd);
++fit;
}
BOOST_FOREACH(vertex_descriptor vd, vertices_to_remove)
{
halfedge_descriptor hd=halfedge(vd, tmesh);
BOOST_FOREACH(halfedge_descriptor hd2, halfedges_around_target(hd, tmesh))
if (!is_border(hd2, tmesh))
degenerate_face_set.erase( face(hd2, tmesh) );
// remove the central vertex and check if the new face is degenerated
hd=CGAL::Euler::remove_center_vertex(hd, tmesh);
if (is_degenerate_triangle_face(face(hd, tmesh), tmesh, vpmap, traits))
{
degenerate_face_set.insert( face(hd, tmesh) );
/// \todo shall we retest the degree of these vertices?
}
}
}
while (!degenerate_face_set.empty())
{
#ifdef CGAL_PMP_REMOVE_DEGENERATE_FACES_DEBUG
std::cout << "Loop on removing deg faces\n";
// ensure the mesh is not broken
{
std::ofstream out("/tmp/out.off");
out << tmesh;
out.close();
std::vector<typename Traits::Point_3> points;
std::vector<std::vector<std::size_t> > triangles;
std::ifstream in("/tmp/out.off");
CGAL::read_OFF(in, points, triangles);
if (!CGAL::Polygon_mesh_processing::is_polygon_soup_a_polygon_mesh(triangles))
{
std::cerr << "ERROR: got a polygon soup!\n";
exit(EXIT_FAILURE);
}
}
#endif
face_descriptor fd = *degenerate_face_set.begin();
// look whether an incident triangle is also degenerated
bool detect_cc_of_degenerate_triangles = false;
BOOST_FOREACH(halfedge_descriptor hd,
halfedges_around_face(halfedge(fd, tmesh), tmesh) )
{
face_descriptor adjacent_face = face( opposite(hd, tmesh), tmesh );
if ( adjacent_face!=GT::null_face() &&
degenerate_face_set.count(adjacent_face) )
{
detect_cc_of_degenerate_triangles = true;
break;
}
}
if (!detect_cc_of_degenerate_triangles)
{
#ifdef CGAL_PMP_REMOVE_DEGENERATE_FACES_DEBUG
std::cout << " no degenerate neighbors, using a flip.\n";
#endif
degenerate_face_set.erase(degenerate_face_set.begin());
// flip the longest edge of the triangle
const typename Traits::Point_3& p1 = get(vpmap, target( halfedge(fd, tmesh), tmesh) );
const typename Traits::Point_3& p2 = get(vpmap, target(next(halfedge(fd, tmesh), tmesh), tmesh) );
const typename Traits::Point_3& p3 = get(vpmap, source( halfedge(fd, tmesh), tmesh) );
CGAL_assertion(p1!=p2 && p1!=p3 && p2!=p3);
typename Traits::Compare_distance_3 compare_distance = traits.compare_distance_3_object();
halfedge_descriptor edge_to_flip;
if (compare_distance(p1,p2, p1,p3) != CGAL::SMALLER) // p1p2 > p1p3
{
if (compare_distance(p1,p2, p2,p3) != CGAL::SMALLER) // p1p2 > p2p3
// flip p1p2
edge_to_flip = next( halfedge(fd, tmesh), tmesh );
else
// flip p2p3
edge_to_flip = prev( halfedge(fd, tmesh), tmesh );
}
else
if (compare_distance(p1,p3, p2,p3) != CGAL::SMALLER) // p1p3>p2p3
//flip p3p1
edge_to_flip = halfedge(fd, tmesh);
else
//flip p2p3
edge_to_flip = prev( halfedge(fd, tmesh), tmesh );
face_descriptor opposite_face=face( opposite(edge_to_flip, tmesh), tmesh);
if ( opposite_face == GT::null_face() )
// simply remove the face
Euler::remove_face(edge_to_flip, tmesh);
else
{
// condition for the flip to be valid (the edge to be created do not already exists)
if ( !halfedge(target(next(edge_to_flip, tmesh), tmesh),
target(next(opposite(edge_to_flip, tmesh), tmesh), tmesh),
tmesh).second )
{
Euler::flip_edge(edge_to_flip, tmesh);
}
#ifdef CGAL_PMP_REMOVE_DEGENERATE_FACES_DEBUG
else
std::cout << " WARNING: flip is not possible\n";
#endif
}
}
else
{
// Process a connected component of degenerate faces
// get all the faces from the connected component
// and the boundary edges
/// \todo the code below is only working if the set of degenerate faces is a topological disk!
std::set<face_descriptor> cc_faces;
std::vector<face_descriptor> queue;
std::vector<halfedge_descriptor> boundary_hedges;
std::vector<halfedge_descriptor> inside_hedges;
queue.push_back(fd);
cc_faces.insert(fd);
while(!queue.empty())
{
face_descriptor top=queue.back();
queue.pop_back();
BOOST_FOREACH(halfedge_descriptor hd,
halfedges_around_face(halfedge(top, tmesh), tmesh) )
{
face_descriptor adjacent_face = face( opposite(hd, tmesh), tmesh );
if ( adjacent_face==GT::null_face() ||
degenerate_face_set.count(adjacent_face)==0 )
boundary_hedges.push_back(hd);
else
{
if (cc_faces.insert(adjacent_face).second)
queue.push_back(adjacent_face);
if ( hd < opposite(hd, tmesh) )
inside_hedges.push_back(hd);
}
}
}
#ifdef CGAL_PMP_REMOVE_DEGENERATE_FACES_DEBUG
std::cout << " Deal with a cc of " << cc_faces.size() << " degenerate faces.\n";
/// dump cc_faces
{
int id=0;
std::map<vertex_descriptor, int> vids;
BOOST_FOREACH(face_descriptor f, cc_faces)
{
if ( vids.insert( std::make_pair( target(halfedge(f, tmesh), tmesh), id) ).second ) ++id;
if ( vids.insert( std::make_pair( target(next(halfedge(f, tmesh), tmesh), tmesh), id) ).second ) ++id;
if ( vids.insert( std::make_pair( target(next(next(halfedge(f, tmesh), tmesh), tmesh), tmesh), id) ).second ) ++id;
}
std::ofstream output("/tmp/cc_faces.off");
output << std::setprecision(44);
output << "OFF\n" << vids.size() << " " << cc_faces.size() << " 0\n";
std::vector<typename Traits::Point_3> points(vids.size());
typedef std::pair<const vertex_descriptor, int> Pair_type;
BOOST_FOREACH(Pair_type p, vids)
points[p.second]=get(vpmap, p.first);
BOOST_FOREACH(typename Traits::Point_3 p, points)
output << p << "\n";
BOOST_FOREACH(face_descriptor f, cc_faces)
{
output << "3 "
<< vids[ target(halfedge(f, tmesh), tmesh) ] << " "
<< vids[ target(next(halfedge(f, tmesh), tmesh), tmesh) ] << " "
<< vids[ target(next(next(halfedge(f, tmesh), tmesh), tmesh), tmesh) ] << "\n";
}
for (std::size_t pid=2; pid!=points.size(); ++pid)
{
CGAL_assertion(collinear(points[0], points[1], points[pid]));
}
}
#endif
// find vertices strictly inside the cc
std::set<vertex_descriptor> boundary_vertices;
BOOST_FOREACH(halfedge_descriptor hd, boundary_hedges)
boundary_vertices.insert( target(hd, tmesh) );
std::set<vertex_descriptor> inside_vertices;
BOOST_FOREACH(halfedge_descriptor hd, inside_hedges)
{
if (!boundary_vertices.count( target(hd, tmesh) ))
inside_vertices.insert( target(hd, tmesh) );
if (!boundary_vertices.count( source(hd, tmesh) ))
inside_vertices.insert( source(hd, tmesh) );
}
// preliminary step to check if the operation is possible
// sort the boundary points along the common supporting line
// we first need a reference point
typedef Less_vertex_point<TriangleMesh, VertexPointMap, Traits> Less_vertex;
std::pair<
typename std::set<vertex_descriptor>::iterator,
typename std::set<vertex_descriptor>::iterator > ref_vertices =
boost::minmax_element( boundary_vertices.begin(),
boundary_vertices.end(),
Less_vertex(traits, vpmap) );
// and then we sort the vertices using this reference point
typedef Less_along_ray<Traits> Less_point;
typedef std::set<typename Traits::Point_3, Less_point> Sorted_point_set;
Sorted_point_set sorted_points( Less_point( traits, get(vpmap, *ref_vertices.first) ) );
BOOST_FOREACH(vertex_descriptor v, boundary_vertices)
sorted_points.insert( get(vpmap,v) );
CGAL_assertion( get( vpmap, *ref_vertices.first)==*sorted_points.begin() );
CGAL_assertion( get( vpmap, *ref_vertices.second)==*cpp11::prev(sorted_points.end()) );
const typename Traits::Point_3& xtrm1 = *sorted_points.begin();
const typename Traits::Point_3& xtrm2 = *cpp11::prev(sorted_points.end());
// recover halfedges on the hole, bounded by the reference vertices
std::vector<halfedge_descriptor> side_one, side_two;
// look for the outgoing border halfedge of the first extreme point
BOOST_FOREACH(halfedge_descriptor hd, boundary_hedges)
if ( get(vpmap, source(hd, tmesh)) == xtrm1 )
{
side_one.push_back(hd);
break;
}
CGAL_assertion(side_one.size()==1);
while( get(vpmap, target(side_one.back(), tmesh)) != xtrm2 )
{
vertex_descriptor prev_vertex = target(side_one.back(), tmesh);
BOOST_FOREACH(halfedge_descriptor hd, boundary_hedges)
if ( source(hd, tmesh) == prev_vertex )
{
side_one.push_back(hd);
break;
}
}
// look for the outgoing border halfedge of the first extreme point
BOOST_FOREACH(halfedge_descriptor hd, boundary_hedges)
if ( get(vpmap, source(hd, tmesh)) == xtrm2 )
{
side_two.push_back(hd);
break;
}
CGAL_assertion(side_two.size()==1);
while( get(vpmap, target(side_two.back(), tmesh)) != xtrm1 )
{
vertex_descriptor prev_vertex = target(side_two.back(), tmesh);
BOOST_FOREACH(halfedge_descriptor hd, boundary_hedges)
if ( source(hd, tmesh) == prev_vertex )
{
side_two.push_back(hd);
break;
}
}
CGAL_assertion( side_one.size()+side_two.size()==boundary_hedges.size() );
// reverse the order of the second side so as to follow
// the same order than side one
std::reverse(side_two.begin(), side_two.end());
BOOST_FOREACH(halfedge_descriptor& h, side_two)
h=opposite(h, tmesh);
CGAL_assertion( source(side_one.front(), tmesh) == *ref_vertices.first );
CGAL_assertion( source(side_two.front(), tmesh) == *ref_vertices.first );
CGAL_assertion( target(side_one.back(), tmesh) == *ref_vertices.second );
CGAL_assertion( target(side_two.back(), tmesh) == *ref_vertices.second );
// sort halfedges to make binary_search calls in the container
std::sort(boundary_hedges.begin(), boundary_hedges.end());
typename Sorted_point_set::iterator it_pt = cpp11::next(sorted_points.begin()),
it_pt_end = cpp11::prev(sorted_points.begin());
bool non_collapsable = false;
typename std::vector<halfedge_descriptor>::iterator side_one_it = side_one.begin();
typename std::vector<halfedge_descriptor>::iterator side_two_it = side_two.begin();
for(;it_pt!=it_pt_end;++it_pt)
{
vertex_descriptor v2 = target(next(opposite(*side_two_it, tmesh), tmesh), tmesh);
halfedge_descriptor h1 = next(*side_one_it, tmesh);
while( !std::binary_search(boundary_hedges.begin(), boundary_hedges.end(), h1) )
{
BOOST_FOREACH(halfedge_descriptor h2, halfedges_around_face(h1, tmesh))
{
CGAL_assertion (!std::binary_search(boundary_hedges.begin(), boundary_hedges.end(), h2));
if (source(h2, tmesh) == v2)
{
non_collapsable = true;
break;
}
}
if (non_collapsable) break;
h1=next(opposite(h1, tmesh), tmesh);
}
if (non_collapsable) break;
CGAL_assertion( get(vpmap, target(*side_one_it, tmesh)) == *it_pt ||
get(vpmap, target(*side_two_it, tmesh)) == *it_pt );
if ( get(vpmap, target(*side_one_it, tmesh)) == *it_pt )
++side_one_it;
if ( get(vpmap, target(*side_two_it, tmesh)) == *it_pt )
++side_two_it;
}
if (non_collapsable){
BOOST_FOREACH(face_descriptor f, cc_faces)
degenerate_face_set.erase(f);
#ifdef CGAL_PMP_REMOVE_DEGENERATE_FACES_DEBUG
std::cout << " WARNING: cannot remove a connected components of degenerate faces.\n";
#endif
continue;
}
// now proceed to the fix
// update the face and halfedge vertex pointers on the boundary
BOOST_FOREACH(halfedge_descriptor h, boundary_hedges)
{
set_face(h, GT::null_face(), tmesh);
set_halfedge(target(h,tmesh), h, tmesh);
}
// update next/prev pointers of boundary_hedges
BOOST_FOREACH(halfedge_descriptor h, boundary_hedges)
{
halfedge_descriptor next_candidate = next( h, tmesh);
while (face(next_candidate, tmesh)!=GT::null_face())
next_candidate = next( opposite( next_candidate, tmesh), tmesh);
set_next(h, next_candidate, tmesh);
}
// remove degenerate faces
BOOST_FOREACH(face_descriptor f, cc_faces)
{
degenerate_face_set.erase(f);
remove_face(f, tmesh);
}
// remove interior edges
BOOST_FOREACH(halfedge_descriptor h, inside_hedges)
remove_edge(edge(h, tmesh), tmesh);
// remove interior vertices
BOOST_FOREACH(vertex_descriptor v, inside_vertices)
remove_vertex(v, tmesh);
#ifdef CGAL_PMP_REMOVE_DEGENERATE_FACES_DEBUG
std::cout << " side_one.size() " << side_one.size() << "\n";
std::cout << " side_two.size() " << side_two.size() << "\n";
#endif
CGAL_assertion( source(side_one.front(), tmesh) == *ref_vertices.first );
CGAL_assertion( source(side_two.front(), tmesh) == *ref_vertices.first );
CGAL_assertion( target(side_one.back(), tmesh) == *ref_vertices.second );
CGAL_assertion( target(side_two.back(), tmesh) == *ref_vertices.second );
// now split each side to contains the same sequence of points
// first side
int hi=0;
for (typename Sorted_point_set::iterator it=cpp11::next(sorted_points.begin()),
it_end=sorted_points.end(); it!=it_end; ++it)
{
CGAL_assertion( *cpp11::prev(it) == get(vpmap, source(side_one[hi], tmesh) ) );
if( *it != get(vpmap, target(side_one[hi], tmesh) ) ){
// split the edge and update the point
halfedge_descriptor h1 = next(opposite(side_one[hi], tmesh), tmesh);
put(vpmap,
target(Euler::split_edge(side_one[hi], tmesh), tmesh),
*it);
// split_edge updates the halfedge of the source vertex of h,
// since we reuse later the halfedge of the first refernce vertex
// we must set it as we need.
if ( source(h1,tmesh) == *ref_vertices.first)
set_halfedge(*ref_vertices.first, prev( prev(side_one[hi], tmesh), tmesh), tmesh );
// retriangulate the opposite face
if ( face(h1, tmesh) != GT::null_face())
Euler::split_face(h1, opposite(side_one[hi], tmesh), tmesh);
}
else
++hi;
}
// second side
hi=0;
for (typename Sorted_point_set::iterator it=cpp11::next(sorted_points.begin()),
it_end=sorted_points.end(); it!=it_end; ++it)
{
CGAL_assertion( *cpp11::prev(it) == get(vpmap, source(side_two[hi], tmesh) ) );
if( *it != get(vpmap, target(side_two[hi], tmesh) ) ){
// split the edge and update the point
halfedge_descriptor h2 = Euler::split_edge(side_two[hi], tmesh);
put(vpmap, target(h2, tmesh), *it);
// split_edge updates the halfedge of the source vertex of h,
// since we reuse later the halfedge of the first refernce vertex
// we must set it as we need.
if ( source(h2,tmesh) == *ref_vertices.first)
set_halfedge(*ref_vertices.first, opposite( h2, tmesh), tmesh );
// retriangulate the face
if ( face(h2, tmesh) != GT::null_face())
Euler::split_face(h2, next(side_two[hi], tmesh), tmesh);
}
else
++hi;
}
CGAL_assertion( target(halfedge(*ref_vertices.first, tmesh), tmesh) == *ref_vertices.first );
CGAL_assertion( face(halfedge(*ref_vertices.first, tmesh), tmesh) == GT::null_face() );
#ifdef CGAL_PMP_REMOVE_DEGENERATE_FACES_DEBUG
{
halfedge_descriptor h_side2 = halfedge(*ref_vertices.first, tmesh);
halfedge_descriptor h_side1 = next(h_side2, tmesh);
do
{
CGAL_assertion( get(vpmap, source(h_side1, tmesh)) == get(vpmap, target(h_side2, tmesh)) );
CGAL_assertion( get(vpmap, target(h_side1, tmesh)) == get(vpmap, source(h_side2, tmesh)) );
if ( target(next(opposite(h_side1, tmesh), tmesh), tmesh) ==
target(next(opposite(h_side2, tmesh), tmesh), tmesh) )
{
CGAL_assertion(!"Forbidden simplification");
}
h_side2 = prev(h_side2, tmesh);
h_side1 = next(h_side1, tmesh);
}
while( target(h_side1, tmesh) != *ref_vertices.second );
}
#endif
// remove side1 and replace its opposite hedges by those of side2
halfedge_descriptor h_side2 = halfedge(*ref_vertices.first, tmesh);
halfedge_descriptor h_side1 = next(h_side2, tmesh);
while(true)
{
CGAL_assertion( get(vpmap, source(h_side1, tmesh)) == get(vpmap, target(h_side2, tmesh)) );
CGAL_assertion( get(vpmap, target(h_side1, tmesh)) == get(vpmap, source(h_side2, tmesh)) );
// backup target vertex
vertex_descriptor vertex_to_remove = target(h_side1, tmesh);
if (vertex_to_remove!=*ref_vertices.second){
vertex_descriptor replacement_vertex = source(h_side2, tmesh);
// replace the incident vertex
BOOST_FOREACH(halfedge_descriptor hd, halfedges_around_target(h_side1, tmesh))
set_target(hd, replacement_vertex, tmesh);
}
// prev side2 hedge for next loop
halfedge_descriptor h_side2_for_next_turn = prev(h_side2, tmesh);
// replace the opposite of h_side1 by h_side2
halfedge_descriptor opposite_h_side1 = opposite( h_side1, tmesh);
face_descriptor the_face = face(opposite_h_side1, tmesh);
set_face(h_side2, the_face, tmesh);
if (the_face!=GT::null_face()) set_halfedge(the_face, h_side2, tmesh);
set_next(h_side2, next(opposite_h_side1, tmesh), tmesh);
set_next(prev(opposite_h_side1, tmesh), h_side2, tmesh);
// take the next hedges
edge_descriptor edge_to_remove = edge(h_side1, tmesh);
h_side1 = next(h_side1, tmesh);
// now remove the extra edge
remove_edge(edge_to_remove, tmesh);
// ... and the extra vertex if it's not the second reference
if (vertex_to_remove==*ref_vertices.second)
{
// update the halfedge pointer of the last vertex (others were already from side 2)
CGAL_assertion( target(opposite(h_side2, tmesh), tmesh) == vertex_to_remove );
set_halfedge(vertex_to_remove, opposite(h_side2, tmesh), tmesh);
break;
}
else
remove_vertex(vertex_to_remove , tmesh);
h_side2 = h_side2_for_next_turn;
}
}
}
return nb_deg_faces;
}
template<class TriangleMesh>
std::size_t remove_degenerate_faces(TriangleMesh& tmesh)
{
return remove_degenerate_faces(tmesh,
CGAL::Polygon_mesh_processing::parameters::all_default());
}
/// \endcond
/// \ingroup PMP_repairing_grp
/// removes the isolated vertices from any polygon mesh.
/// A vertex is considered isolated if it is not incident to any simplex
/// of higher dimension.
///
/// @tparam PolygonMesh a model of `FaceListGraph` and `MutableFaceGraph`
///
/// @param pmesh the polygon mesh to be repaired
///
/// @return number of removed isolated vertices
///
template <class PolygonMesh>
std::size_t remove_isolated_vertices(PolygonMesh& pmesh)
{
typedef typename boost::graph_traits<PolygonMesh>::vertex_descriptor vertex_descriptor;
std::vector<vertex_descriptor> to_be_removed;
BOOST_FOREACH(vertex_descriptor v, vertices(pmesh))
{
if (CGAL::halfedges_around_target(v, pmesh).first
== CGAL::halfedges_around_target(v, pmesh).second)
to_be_removed.push_back(v);
}
std::size_t nb_removed = to_be_removed.size();
BOOST_FOREACH(vertex_descriptor v, to_be_removed)
{
remove_vertex(v, pmesh);
}
return nb_removed;
}
/// \cond SKIP_IN_MANUAL
namespace internal{
template <class Descriptor>
struct Is_selected{
std::set<Descriptor>& selection;
Is_selected(std::set<Descriptor>& sel)
:selection(sel)
{}
friend bool get(Is_selected is, Descriptor d){
return is.selection.count(d);
}
friend void put(Is_selected is, Descriptor d, bool b){
if (b)
is.selection.insert(d);
else
is.selection.erase(d);
}
};
} // end of namespace internal
template <class TriangleMesh, class halfedge_descriptor, class face_descriptor>
bool remove_self_intersections_one_step(TriangleMesh& tm,
std::set<face_descriptor>& faces_to_remove,
std::vector<halfedge_descriptor>& non_filled_hole,
int step,
bool verbose)
{
typedef boost::graph_traits<TriangleMesh> graph_traits;
typedef typename graph_traits::vertex_descriptor vertex_descriptor;
typedef typename graph_traits::edge_descriptor edge_descriptor;
bool no_hole_was_filled=true; // indicates if the filling of all previously
// created holes failed.
if (verbose)
std::cout << "DEBUG: is_valid(tm)? " << is_valid(tm) << "\n";
std::vector<halfedge_descriptor> one_halfedge_per_border;
if(!faces_to_remove.empty() || !non_filled_hole.empty()){
// expand the region to be filled
internal::Is_selected<face_descriptor> is_selected(faces_to_remove);
expand_face_selection(faces_to_remove, tm, step+1, is_selected, Emptyset_iterator());
// try to avoid non-manifold vertices (morpho-math)
reduce_face_selection(faces_to_remove, tm, 1, is_selected, Emptyset_iterator());
// now expand holes than were not filled
std::vector<halfedge_descriptor> boundary_hedges; // this container will contain the halfedges of
// all created holes
std::set<halfedge_descriptor> border_created; // track border halfedges that were previously created
// to avoid considering them as original mesh border
// edges that should be kept
BOOST_FOREACH(halfedge_descriptor h, non_filled_hole)
{
select_incident_faces(halfedges_around_face(h,tm), tm,
std::inserter(faces_to_remove, faces_to_remove.begin()) );
BOOST_FOREACH(halfedge_descriptor h2, halfedges_around_face(h,tm))
{
CGAL_assertion(is_border(h2, tm));
border_created.insert(h2);
if ( is_border(opposite(h2, tm), tm) )
boundary_hedges.push_back(h2); // mesh border halfedges should be re-added
}
}
non_filled_hole.clear();
/// save the halfedges that will get on the boundary
bool border_edges_found=false; // indicates at least one face incident to
// the mesh border will be removed. In that
// case, border halfedges should not be removed.
// extract the set of halfedges that is on the boundary of the holes to be
// made. In addition, we make sure no hole to be created contains a vertex
// visited more than once along a hole border (pinched surface)
// We save the size of boundary_hedges to make sur halfedges added
// from non_filled_hole are not removed.
bool non_manifold_vertex_removed; //here non-manifold is for the 1D polyline
std::size_t boundary_hedges_initial_size=boundary_hedges.size();
do{
non_manifold_vertex_removed=false;
boundary_hedges.resize(boundary_hedges_initial_size);
BOOST_FOREACH(face_descriptor fh, faces_to_remove)
{
halfedge_descriptor h = halfedge(fh,tm);
for (int i=0;i<3; ++i)
{
if ( is_border( opposite(h, tm), tm) ){
if (!border_created.count(opposite(h, tm))){
// only border halfedges that were not created by a previous face
// removal should be considered as hole boundary
boundary_hedges.push_back(h);
border_edges_found=true;
}
}
else
if ( !faces_to_remove.count( face( opposite(h, tm), tm) ) )
boundary_hedges.push_back(h);
h=next(h, tm);
}
}
// detect vertices visited more than once along
// a hole border. We then remove all faces incident
// to such a vertex to force the removal of the vertex.
// Actually even if two holes are sharing a vertex, this
// vertex will be removed. It is not needed but since
// we do not yet have one halfedge per hole it is simpler
// and does not harm
std::set<vertex_descriptor> border_vertices;
BOOST_FOREACH(halfedge_descriptor h, boundary_hedges)
{
if (!border_vertices.insert(target(h,tm)).second){
BOOST_FOREACH(halfedge_descriptor hh, halfedges_around_target(h,tm)){
if (!is_border(hh, tm))
faces_to_remove.insert(face(hh, tm));
}
non_manifold_vertex_removed=true;
}
}
}
while(non_manifold_vertex_removed);
/// remove the selection
if (border_edges_found){
// When at least one face incident to the mesh border is set
// to be removed, we should pay attention not to remove
// the border halfedge that is part of the mesh.
// first collect all vertices and edges incident to the faces to remove
std::set<vertex_descriptor> vertices_to_remove;
std::set<edge_descriptor> edges_to_remove;
BOOST_FOREACH(face_descriptor fh, faces_to_remove)
{
BOOST_FOREACH(halfedge_descriptor h, halfedges_around_face(halfedge(fh,tm),tm))
{
if (halfedge(target(h, tm), tm)==h) // limit the number of insertions
vertices_to_remove.insert(target(h, tm));
edges_to_remove.insert(edge(h,tm));
}
}
// detect cycles of input border halfedges:
// if such a cycle is found input border halfedges are removed to
// remove small border cycle that are imposing a self-intersection
// that could not be fixed if kept. (This also prevent small island
// if a small hole is incident to the faces to be removed).
if (border_edges_found){
std::set<halfedge_descriptor> cycles;
std::set<halfedge_descriptor> boundary_set;
BOOST_FOREACH(halfedge_descriptor h, boundary_hedges)
{
if ( is_border(opposite(h, tm), tm) )
boundary_set.insert(opposite(h, tm));
}
BOOST_FOREACH(halfedge_descriptor hd, boundary_set)
{
CGAL_assertion(is_border(hd,tm));
if(cycles.count(hd)) continue;
halfedge_descriptor nhd=next(hd,tm);
bool remove_it=true;
do{
if (!boundary_set.count(nhd))
{
remove_it=false;
break;
}
nhd=next(nhd,tm);
}
while(nhd!=hd);
if (remove_it){
BOOST_FOREACH(halfedge_descriptor h, halfedges_around_face(hd,tm))
cycles.insert(h);
}
}
//remove cycle edges
if (!cycles.empty())
{
std::vector<halfedge_descriptor> tmp;
tmp.reserve(boundary_hedges.size()-cycles.size());
BOOST_FOREACH(halfedge_descriptor h, boundary_hedges)
{
if (!cycles.count(opposite(h, tm)))
tmp.push_back(h);
}
tmp.swap(boundary_hedges);
}
}
// do not remove edges on the boundary of the selection of faces,
// nor its vertices
BOOST_FOREACH(halfedge_descriptor h, boundary_hedges)
{
vertices_to_remove.erase(target(h, tm));
edges_to_remove.erase(edge(h,tm));
}
// now remove edges,
BOOST_FOREACH(edge_descriptor e, edges_to_remove)
remove_edge(e, tm);
// and vertices,
BOOST_FOREACH(vertex_descriptor vh, vertices_to_remove)
remove_vertex(vh, tm);
// and finally facets
BOOST_FOREACH(face_descriptor f, faces_to_remove)
remove_face(f, tm);
// set new border_vertices to the boundary and update
// the halfedge pointer of the border vertices
BOOST_FOREACH(halfedge_descriptor h, boundary_hedges)
{
set_face(h,graph_traits::null_face(), tm);
set_halfedge(target(h, tm), h, tm);
set_next(h,h,tm); // set himself as next to track edges of the holes
}
// update next/prev relationships of the hole
BOOST_FOREACH(halfedge_descriptor h, boundary_hedges)
{
halfedge_descriptor nh=next(opposite(h, tm), tm);
while( !is_border(opposite(nh, tm), tm) ||
next(opposite(nh, tm), tm) != opposite(nh, tm)) //this part makes sure we consider halfedges of the hole
{
nh=next(opposite(nh, tm), tm);
CGAL_assertion(nh!=h);
}
CGAL_assertion(next(opposite(nh, tm), tm)==opposite(nh,tm));
set_next(opposite(nh, tm), h, tm);
}
}
else
/// \todo check whether this is more expensive than the previous code above
BOOST_FOREACH(face_descriptor f, faces_to_remove)
Euler::remove_face(halfedge(f, tm), tm);
if (verbose)
std::cout << " DEBUG: " << faces_to_remove.size() << " triangles removed" << std::endl;
/// now get one halfedge per hole
std::set<halfedge_descriptor> visited;
BOOST_FOREACH(halfedge_descriptor h, boundary_hedges)
{
if (visited.insert(h).second)
{
one_halfedge_per_border.push_back(h);
BOOST_FOREACH(halfedge_descriptor hh, halfedges_around_face(h, tm))
{
CGAL_assertion_code(bool insert_ok =)
visited.insert(hh)
CGAL_assertion_code(.second);
CGAL_assertion(insert_ok || h==hh);
}
}
}
}
if (!one_halfedge_per_border.empty()){
BOOST_FOREACH(halfedge_descriptor h, one_halfedge_per_border)
{
std::size_t nb_new_triangles = 0;
Counting_output_iterator out(&nb_new_triangles);
triangulate_hole(tm, h, out);
if (!nb_new_triangles)
{
if (verbose)
std::cout << " DEBUG: Failed to fill a hole!!!" << std::endl;
non_filled_hole.push_back(h);
}
else
no_hole_was_filled=false;
}
if (verbose)
std::cout << " DEBUG: Number of holes " << one_halfedge_per_border.size() << std::endl;
}
else{
if (verbose)
std::cout << "INFO: Nothing to correct\n";
}
return no_hole_was_filled;
}
template <class TriangleMesh>
bool remove_self_intersections(TriangleMesh& tm, const int max_steps = 7, bool verbose=false)
{
typedef boost::graph_traits<TriangleMesh> graph_traits;
typedef typename graph_traits::halfedge_descriptor halfedge_descriptor;
typedef typename graph_traits::face_descriptor face_descriptor;
std::vector<halfedge_descriptor> non_filled_hole;
// first handle the removal of degenerate faces
std::set<face_descriptor> deg_faces;
degenerate_faces(tm, std::inserter(deg_faces, deg_faces.begin()));
remove_self_intersections_one_step(tm, deg_faces, non_filled_hole, 2, verbose);
// Look for self-intersections in the polyhedron and remove them
int step=-1;
bool no_hole_was_filled=false; // indicates if the filling of all previously
// created holes failed. If true then no new
// self-intersection have been created and
// checking for it is useless.
while( ++step<max_steps )
{
if (verbose)
std::cout << "DEBUG: is_valid(tm)? " << is_valid(tm) << "\n";
typedef std::pair<face_descriptor, face_descriptor> Face_pair;
std::vector<Face_pair> self_inter;
std::vector<halfedge_descriptor> one_halfedge_per_border;
if (!no_hole_was_filled)
self_intersections(tm, std::back_inserter(self_inter));
std::set<face_descriptor> faces_to_remove;
BOOST_FOREACH(Face_pair fp, self_inter)
{
faces_to_remove.insert(fp.first);
faces_to_remove.insert(fp.second);
}
if (verbose)
std::cout << "DEBUG: Iterative self-intersection removal step " << step
<< " - non_filled_hole.size() = " << non_filled_hole.size() << std::endl;
if ( faces_to_remove.empty() && non_filled_hole.empty() )
break;
no_hole_was_filled =
remove_self_intersections_one_step(tm, faces_to_remove, non_filled_hole,step, verbose);
}
return step<max_steps;
}
/// \endcond
} } // end of CGAL::Polygon_mesh_processing
#endif // CGAL_POLYGON_MESH_PROCESSING_REPAIR_H
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