mirror of https://github.com/CGAL/cgal
71 lines
2.5 KiB
C++
71 lines
2.5 KiB
C++
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
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#include <CGAL/boost/graph/graph_traits_Triangulation_2.h>
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#include <boost/graph/dijkstra_shortest_paths.hpp>
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#include <fstream>
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typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
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typedef K::Point_2 Point;
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typedef CGAL::Triangulation_2<K> Triangulation;
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typedef boost::graph_traits<Triangulation>::vertex_descriptor vertex_descriptor;
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typedef boost::graph_traits<Triangulation>::vertex_iterator vertex_iterator;
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typedef std::map<vertex_descriptor, int> VertexIndexMap;
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typedef boost::associative_property_map<VertexIndexMap> VertexIdPropertyMap;
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int main(int argc,char* argv[])
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{
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const char* filename = (argc > 1) ? argv[1] : "data/points.xy";
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std::ifstream input(filename);
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Triangulation tr;
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Point p ;
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while(input >> p)
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tr.insert(p);
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vertex_iterator vit, ve;
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// Associate indices to the vertices
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VertexIndexMap vertex_id_map;
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VertexIdPropertyMap vertex_index_pmap(vertex_id_map);
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int index = 0;
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for(vertex_descriptor vd : vertices(tr))
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vertex_id_map[vd] = index++;
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// Dijkstra's shortest path needs property maps for the predecessor and distance
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// We first declare a vector
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std::vector<vertex_descriptor> predecessor(num_vertices(tr));
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// and then turn it into a property map
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boost::iterator_property_map<std::vector<vertex_descriptor>::iterator, VertexIdPropertyMap>
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predecessor_pmap(predecessor.begin(), vertex_index_pmap);
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std::vector<double> distance(num_vertices(tr));
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boost::iterator_property_map<std::vector<double>::iterator, VertexIdPropertyMap>
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distance_pmap(distance.begin(), vertex_index_pmap);
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// start at an arbitrary vertex
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vertex_descriptor source = *vertices(tr).first;
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std::cout << "\nStart dijkstra_shortest_paths at " << source->point() <<"\n";
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boost::dijkstra_shortest_paths(tr, source,
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distance_map(distance_pmap)
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.predecessor_map(predecessor_pmap)
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.vertex_index_map(vertex_index_pmap));
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for(vertex_descriptor vd : vertices(tr))
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{
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std::cout << vd->point() << " [" << vertex_id_map[vd] << "] ";
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std::cout << " has distance = " << get(distance_pmap,vd)
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<< " and predecessor ";
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vd = get(predecessor_pmap,vd);
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std::cout << vd->point() << " [" << vertex_id_map[vd] << "]\n ";
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}
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return EXIT_SUCCESS;
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}
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