mirror of https://github.com/CGAL/cgal
75 lines
3.2 KiB
C++
75 lines
3.2 KiB
C++
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#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
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#include <CGAL/Simple_polygon_visibility_2.h>
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#include <CGAL/Arrangement_2.h>
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#include <CGAL/Arr_segment_traits_2.h>
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#include <CGAL/Arr_naive_point_location.h>
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#include <istream>
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#include <vector>
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typedef CGAL::Exact_predicates_exact_constructions_kernel Kernel;
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typedef Kernel::Point_2 Point_2;
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typedef Kernel::Segment_2 Segment_2;
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typedef CGAL::Arr_segment_traits_2<Kernel> Traits_2;
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typedef CGAL::Arrangement_2<Traits_2> Arrangement_2;
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typedef Arrangement_2::Face_handle Face_handle;
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typedef Arrangement_2::Edge_const_iterator Edge_const_iterator;
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typedef Arrangement_2::Ccb_halfedge_circulator Ccb_halfedge_circulator;
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int main() {
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//create environment
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Point_2 p1(0,4), p2(0,0), p3(3,2), p4(4,0), p5(4,4), p6(1,2);
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std::vector<Segment_2> segments;
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segments.push_back(Segment_2(p1, p2));
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segments.push_back(Segment_2(p2, p3));
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segments.push_back(Segment_2(p3, p4));
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segments.push_back(Segment_2(p4, p5));
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segments.push_back(Segment_2(p5, p6));
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segments.push_back(Segment_2(p6, p1));
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Arrangement_2 env;
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CGAL::insert_non_intersecting_curves(env,segments.begin(),segments.end());
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// find the face of the query point
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// (usually you may know that by other means)
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Point_2 q(0.5, 2);
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Arrangement_2::Face_const_handle * face;
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CGAL::Arr_naive_point_location<Arrangement_2> pl(env);
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CGAL::Arr_point_location_result<Arrangement_2>::Type obj = pl.locate(q);
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// The query point locates in the interior of a face
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face = std::get_if<Arrangement_2::Face_const_handle> (&obj);
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// compute non regularized visibility area
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// Define visibility object type that computes non-regularized visibility area
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typedef CGAL::Simple_polygon_visibility_2<Arrangement_2, CGAL::Tag_false> NSPV;
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Arrangement_2 non_regular_output;
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NSPV non_regular_visibility(env);
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non_regular_visibility.compute_visibility(q, *face, non_regular_output);
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std::cout << "Non-regularized visibility region of q has "
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<< non_regular_output.number_of_edges()
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<< " edges:" << std::endl;
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for (Edge_const_iterator eit = non_regular_output.edges_begin(); eit != non_regular_output.edges_end(); ++eit)
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std::cout << "[" << eit->source()->point() << " -> " << eit->target()->point() << "]" << std::endl;
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// compute non regularized visibility area
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// Define visibility object type that computes regularized visibility area
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typedef CGAL::Simple_polygon_visibility_2<Arrangement_2, CGAL::Tag_true> RSPV;
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Arrangement_2 regular_output;
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RSPV regular_visibility(env);
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regular_visibility.compute_visibility(q, *face, regular_output);
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std::cout << "Regularized visibility region of q has "
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<< regular_output.number_of_edges()
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<< " edges:" << std::endl;
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for (Edge_const_iterator eit = regular_output.edges_begin(); eit != regular_output.edges_end(); ++eit)
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std::cout << "[" << eit->source()->point() << " -> " << eit->target()->point() << "]" << std::endl;
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return 0;
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}
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