CGAL 5.6.3 - 2D Triangulations

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Triangulation_2/polygon_triangulation.cpp
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Constrained_Delaunay_triangulation_2.h>
#include <CGAL/draw_triangulation_2.h>
#include <CGAL/mark_domain_in_triangulation.h>
#include <CGAL/Polygon_2.h>
#include <iostream>
#include <unordered_map>
#include <boost/property_map/property_map.hpp>
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Triangulation_vertex_base_2<K> Vb;
typedef CGAL::Constrained_triangulation_face_base_2<K> Fb;
typedef CGAL::Triangulation_data_structure_2<Vb,Fb> TDS;
typedef CGAL::Exact_predicates_tag Itag;
typedef CGAL::Constrained_Delaunay_triangulation_2<K, TDS, Itag> CDT;
typedef CDT::Face_handle Face_handle;
typedef CDT::Point Point;
typedef CGAL::Polygon_2<K> Polygon_2;
int main( )
{
//construct two non-intersecting nested polygons
Polygon_2 polygon1;
polygon1.push_back(Point(0,0));
polygon1.push_back(Point(2,0));
polygon1.push_back(Point(2,2));
polygon1.push_back(Point(1,1.75));
polygon1.push_back(Point(0,2));
Polygon_2 polygon2;
polygon2.push_back(Point(0.5,0.5));
polygon2.push_back(Point(1.5,0.5));
polygon2.push_back(Point(1.5,1.5));
polygon2.push_back(Point(0.5,1.5));
//Insert the polygons into a constrained triangulation
CDT cdt;
cdt.insert_constraint(polygon1.vertices_begin(), polygon1.vertices_end(), true);
cdt.insert_constraint(polygon2.vertices_begin(), polygon2.vertices_end(), true);
cdt.insert_constraint(Point(0.25, 0.25), Point(0.25, 1.75));
std::unordered_map<Face_handle, bool> in_domain_map;
boost::associative_property_map< std::unordered_map<Face_handle,bool> >
in_domain(in_domain_map);
//Mark facets that are inside the domain bounded by the polygon
CGAL::mark_domain_in_triangulation(cdt, in_domain);
unsigned int count=0;
for (Face_handle f : cdt.finite_face_handles())
{
if ( get(in_domain, f) ) ++count;
}
std::cout << "There are " << count << " faces in the domain." << std::endl;
assert(count > 0);
assert(count < cdt.number_of_faces());
CGAL::draw(cdt, in_domain);
return 0;
}
CGAL::Constrained_Delaunay_triangulation_2
A constrained Delaunay triangulation is a triangulation with constrained edges which tries to be as m...
Definition: Constrained_Delaunay_triangulation_2.h:96
CGAL::Constrained_triangulation_face_base_2
The class Constrained_triangulation_face_base_2 is the default model for the concept ConstrainedTrian...
Definition: Constrained_triangulation_face_base_2.h:34
CGAL::Exact_predicates_inexact_constructions_kernel
CGAL::Polygon_2
CGAL::Polygon_2::push_back
void push_back(const Point_2 &x)
CGAL::Triangulation_data_structure_2
CGAL::Triangulation_vertex_base_2
The class Triangulation_vertex_base_2 is the default model for the concept TriangulationVertexBase_2.
Definition: Triangulation_vertex_base_2.h:34
CGAL::draw
void draw(const T3 &at3)
CGAL::mark_domain_in_triangulation
void mark_domain_in_triangulation(CT &ct, InDomainPmap ipm)
marks faces connected with non constrained edges as inside of the domain based on the nesting level.
CGAL::Exact_predicates_tag
Intersection tag for constrained triangulations, if the geometric traits provides exact predicates bu...
Definition: Constrained_triangulation_2.h:51