CGAL 4.8.2 - 2D Segment Delaunay Graphs
Segment_Delaunay_graph_2/sdg-fast-sp-polygon.cpp
// standard includes
#include <iostream>
#include <fstream>
#include <cassert>
// example that uses the filtered traits,
// the segment Delaunay graph and the spatial sorting
// choose the kernel
#include <CGAL/Simple_cartesian.h>
// typedefs for the traits and the algorithm
#include <CGAL/Segment_Delaunay_graph_2.h>
#include <CGAL/Segment_Delaunay_graph_filtered_traits_2.h>
int main()
{
std::ifstream ifs("data/sites.cin");
assert( ifs );
//polygon points
std::vector<Gt::Point_2> points;
//segments of the polygon as a pair of point indices
std::vector<std::pair<std::size_t,std::size_t> > indices;
SDG2::Site_2 site;
//read a close polygon given by its segments
// s x0 y0 x1 y1
// s x1 y1 x2 y2
// ...
// s xn yn x0 y0
ifs >> site;
assert( site.is_segment() );
points.push_back( site.source_of_supporting_site() );
std::size_t k=0;
while ( ifs >> site ) {
assert( site.is_segment() );
points.push_back( site.source_of_supporting_site() );
indices.push_back( std::make_pair(k, k+1) );
++k;
}
indices.push_back( std::make_pair(k, 0) );
ifs.close();
SDG2 sdg;
//insert the polygon segments all at once using spatial sorting to speed the insertion
sdg.insert_segments( points.begin(), points.end(), indices.begin(), indices.end() );
// validate the segment Delaunay graph
assert( sdg.is_valid(true, 1) );
return 0;
}