CGAL 5.1.4 - 2D Triangulation
Triangulation_2/low_dimensional.cpp
#include <iostream>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Triangulation_2.h>
typedef CGAL::Triangulation_2<K> Triangulation;
typedef Triangulation::Vertex_handle Vertex_handle;
typedef Triangulation::Face_handle Face_handle;
typedef Triangulation::All_faces_iterator All_faces_iterator;
typedef Triangulation::All_edges_iterator All_edges_iterator;
typedef Triangulation::Point Point;
int main() {
Point p(0,0), q(1,0);
Triangulation t;
Vertex_handle inf = t.infinite_vertex();
Face_handle fh = inf->face();
assert(fh->vertex(0) == inf);
assert(fh->vertex(1) == Vertex_handle());
assert(fh->vertex(2) == Vertex_handle());
assert(t.all_faces_begin() == t.all_faces_end());
assert(t.all_edges_begin() == t.all_edges_end());
t.insert(p);
Vertex_handle pvh = t.finite_vertices_begin();
Face_handle pfh = pvh->face();
assert(pfh->neighbor(0) == fh);
t.insert(q);
assert(t.infinite_vertex()->face() == fh);
assert( (fh->vertex(0) == inf) || (fh->vertex(1) == inf) );
std::cout << "After the insertion of the second point" <<std::endl;
std::cout << "|V| = " << t.number_of_vertices() << std::endl;
std::cout << "|F| = " << t.number_of_faces() << std::endl;
// Even now we have not really faces
assert(t.all_faces_begin() == t.all_faces_end());
for (Triangulation::All_edges_iterator it = t.all_edges_begin();
it != t.all_edges_end(); ++it) {
Face_handle fh = it->first;
Vertex_handle v0 = fh->vertex(0);
Vertex_handle v1 = fh->vertex(1);
std::cout << "Edge: ";
if (v0 == inf) {std::cout << "inf -- ";}else{ std::cout<< v0->point() << " -- ";}
if (v1 == inf) {std::cout << "inf\n";}else{ std::cout<< v1->point() << std::endl;}
}
std::cout << "Edge traversal by hand" << std::endl;
Face_handle done = fh;
do {
assert(fh->vertex(2) == Vertex_handle());
assert(fh->neighbor(2) == Face_handle());
Vertex_handle v0 = fh->vertex(0);
Vertex_handle v1 = fh->vertex(1);
std::cout << "Edge: ";
if (v0 == inf) {std::cout << "inf -- ";}else{ std::cout<< v0->point() << " -- ";}
if (v1 == inf) {std::cout << "inf\n";}else{ std::cout<< v1->point() << std::endl;}
fh = fh->neighbor(0);
} while (fh != done);
std::cout << std::endl;
return 0;
}