CGAL 6.2 - Fast Intersection and Distance Computation (AABB Tree)

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AABB_tree/AABB_polyline_segment_2_example.cpp
#include <iostream>
#include <vector>
#include <CGAL/Simple_cartesian.h>
#include <CGAL/AABB_tree.h>
#include <CGAL/AABB_traits_2.h>
#include <CGAL/AABB_polyline_segment_primitive_2.h>
#include <CGAL/AABB_segment_primitive_2.h>
#include <CGAL/Polygon_2.h>
typedef CGAL::Simple_cartesian<double> K;
typedef K::Segment_2 Segment;
typedef K::Point_2 Point;
typedef std::vector<Point> PointRange;
typedef PointRange::const_iterator Iterator_pr;
typedef CGAL::AABB_polyline_segment_primitive_2<K, Iterator_pr, PointRange> Primitive_pr;
typedef CGAL::AABB_traits_2<K, Primitive_pr> Traits_pr;
typedef CGAL::AABB_tree<Traits_pr> Tree_pr;
typedef Tree_pr::Point_and_primitive_id Point_and_primitive_id_pr;
typedef CGAL::Polygon_2<K> Polygon_2;
typedef Polygon_2::const_iterator Iterator_poly;
typedef CGAL::AABB_polyline_segment_primitive_2<K, Iterator_poly, Polygon_2> Primitive_poly;
typedef CGAL::AABB_traits_2<K, Primitive_poly> Traits_poly;
typedef CGAL::AABB_tree<Traits_poly> Tree_poly;
typedef Tree_poly::Point_and_primitive_id Point_and_primitive_id_poly;
template<class AABBTree, class PPId>
void test(AABBTree tree) {
tree.build();
tree.accelerate_distance_queries();
// counts #intersections with a segment query
Segment segment_query(Point(1.0, 0.0), Point(0.0, 7.0));
std::cout << tree.number_of_intersected_primitives(segment_query)
<< " intersections(s) with segment" << std::endl;
// computes the closest point from a point query
Point point_query(1.5, 3.0);
Point closest = tree.closest_point(point_query);
std::cerr << "closest point is: " << closest << std::endl;
PPId id = tree.closest_point_and_primitive(point_query);
std::cout << id.first << "\n";
}
int main()
{
Point a(0.0, 0.0);
Point b(2.0, 1.0);
Point c(3.0, 4.0);
Point d(1.0, 6.0);
Point e(-1.0, 3.0);
std::vector<Point> polyline = { a, b, c, d, e };
Polygon_2 poly(polyline.begin(), polyline.end());
test<Tree_poly, Point_and_primitive_id_poly>(Tree_poly(poly.begin(), poly.end(), poly));
// For a point range, the second iterator must be of the second-last point in the range.
// If it points to the end of the range, to polyline is considered to be closed.
test<Tree_pr, Point_and_primitive_id_pr>(Tree_pr(polyline.begin(), std::prev(polyline.end()), polyline));
return EXIT_SUCCESS;
}
CGAL::AABB_polyline_segment_primitive_2
Primitive type that uses as identifier an iterator with a 2D point as value_type.
Definition: AABB_polyline_segment_primitive_2.h:117
CGAL::AABB_traits_2
This traits class handles any type of 2D geometric primitives provided that the proper intersection t...
Definition: AABB_traits_2.h:423
CGAL::AABB_tree
Static data structure for efficient intersection and distance computations in 2D and 3D.
Definition: AABB_tree.h:57
CGAL::AABB_tree::build
void build(T &&...)
triggers the (re)construction of the internal tree structure.
CGAL::Simple_cartesian