1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/Polygon_mesh_processing/connected_components.h>
#include <boost/function_output_iterator.hpp>
#include <boost/property_map/property_map.hpp>
#include <boost/foreach.hpp>
#include <iostream>
#include <fstream>
#include <map>
typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
typedef Kernel::Point_3 Point;
typedef Kernel::Compare_dihedral_angle_3 Compare_dihedral_angle_3;
typedef CGAL::Surface_mesh<Point> Mesh;
namespace PMP = CGAL::Polygon_mesh_processing;
template <typename G>
struct Constraint : public boost::put_get_helper<bool,Constraint<G> >
{
typedef typename boost::graph_traits<G>::edge_descriptor edge_descriptor;
typedef boost::readable_property_map_tag category;
typedef bool value_type;
typedef bool reference;
typedef edge_descriptor key_type;
Constraint()
:g_(NULL)
{}
Constraint(G& g, double bound)
: g_(&g), bound_(bound)
{}
bool operator[](edge_descriptor e) const
{
const G& g = *g_;
return compare_(g.point(source(e, g)),
g.point(target(e, g)),
g.point(target(next(halfedge(e, g), g), g)),
g.point(target(next(opposite(halfedge(e, g), g), g), g)),
bound_) == CGAL::SMALLER;
}
const G* g_;
Compare_dihedral_angle_3 compare_;
double bound_;
};
template <typename PM>
struct Put_true
{
Put_true(const PM pm)
:pm(pm)
{}
template <typename T>
void operator()(const T& t)
{
put(pm, t, true);
}
PM pm;
};
int main(int argc, char* argv[])
{
const char* filename = (argc > 1) ? argv[1] : "data/blobby_3cc.off";
std::ifstream input(filename);
Mesh mesh;
if (!input || !(input >> mesh) || mesh.is_empty()) {
std::cerr << "Not a valid off file." << std::endl;
return 1;
}
typedef boost::graph_traits<Mesh>::face_descriptor face_descriptor;
const double bound = std::cos(0.75 * CGAL_PI);
std::vector<face_descriptor> cc;
face_descriptor fd = *faces(mesh).first;
PMP::connected_component(fd,
mesh,
std::back_inserter(cc));
std::cerr << "Connected components without edge constraints" << std::endl;
std::cerr << cc.size() << " faces in the CC of " << fd << std::endl;
// Instead of writing the faces into a container, you can set a face property to true
typedef Mesh::Property_map<face_descriptor, bool> F_select_map;
F_select_map fselect_map =
mesh.add_property_map<face_descriptor, bool>("f:select", false).first;
PMP::connected_component(fd,
mesh,
boost::make_function_output_iterator(Put_true<F_select_map>(fselect_map)));
std::cerr << "\nConnected components with edge constraints (dihedral angle < 3/4 pi)" << std::endl;
Mesh::Property_map<face_descriptor, std::size_t> fccmap =
mesh.add_property_map<face_descriptor, std::size_t>("f:CC").first;
std::size_t num = PMP::connected_components(mesh,
fccmap,
PMP::parameters::edge_is_constrained_map(Constraint<Mesh>(mesh, bound)));
std::cerr << "- The graph has " << num << " connected components (face connectivity)" << std::endl;
typedef std::map<std::size_t/*index of CC*/, unsigned int/*nb*/> Components_size;
Components_size nb_per_cc;
BOOST_FOREACH(face_descriptor f , faces(mesh)){
nb_per_cc[ fccmap[f] ]++;
}
BOOST_FOREACH(const Components_size::value_type& cc, nb_per_cc){
std::cout << "\t CC #" << cc.first
<< " is made of " << cc.second << " faces" << std::endl;
}
std::cerr << "- We keep only components which have at least 4 faces" << std::endl;
PMP::keep_large_connected_components(mesh,
4,
PMP::parameters::edge_is_constrained_map(Constraint<Mesh>(mesh, bound)));
std::cerr << "- We keep the two largest components" << std::endl;
PMP::keep_largest_connected_components(mesh,
2,
PMP::parameters::edge_is_constrained_map(Constraint<Mesh>(mesh, bound)));
return 0;
}
|
