mirror of https://github.com/CGAL/cgal
62 lines
1.8 KiB
C++
62 lines
1.8 KiB
C++
// example with random points on a sphere
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#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
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#include <CGAL/point_generators_3.h>
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#include <CGAL/algorithm.h>
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#include <CGAL/Origin.h>
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#include <CGAL/surface_neighbor_coordinates_3.h>
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typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
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typedef K::FT Coord_type;
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typedef K::Point_3 Point_3;
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typedef K::Vector_3 Vector_3;
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typedef std::vector< std::pair< Point_3, K::FT > >
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Point_coordinate_vector;
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int main()
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{
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int n=100;
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std::vector< Point_3> points;
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points.reserve(n);
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std::cout << "Generate " << n << " random points on a sphere."
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<< std::endl;
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CGAL::Random_points_on_sphere_3<Point_3> g(1);
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CGAL::copy_n( g, n, std::back_inserter(points));
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Point_3 p(1, 0,0);
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Vector_3 normal(p-CGAL::ORIGIN);
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std::cout << "Compute surface neighbor coordinates for "
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<< p << std::endl;
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Point_coordinate_vector coords;
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CGAL::Triple< std::back_insert_iterator<Point_coordinate_vector>,
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K::FT, bool> result =
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CGAL::surface_neighbor_coordinates_3(points.begin(), points.end(),
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p, normal,
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std::back_inserter(coords),
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K());
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if(!result.third){
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//Undersampling:
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std::cout << "The coordinate computation was not successful."
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<< std::endl;
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return 0;
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}
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K::FT norm = result.second;
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std::cout << "Testing the barycentric property " << std::endl;
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Point_3 b(0, 0,0);
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for(std::vector< std::pair< Point_3, Coord_type > >::const_iterator
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it = coords.begin(); it!=coords.end(); ++it)
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b = b + (it->second/norm)* (it->first - CGAL::ORIGIN);
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std::cout <<" weighted barycenter: " << b <<std::endl;
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std::cout << " squared distance: " <<
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CGAL::squared_distance(p,b) <<std::endl;
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std::cout << "done" << std::endl;
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return 0;
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}
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