CGAL 5.4.1 - Quadtrees, Octrees, and Orthtrees
Orthtree/octree_find_nearest_neighbor.cpp
#include <fstream>
#include <iostream>
#include <CGAL/Simple_cartesian.h>
#include <CGAL/Octree.h>
#include <CGAL/Point_set_3.h>
#include <CGAL/Point_set_3/IO.h>
#include <boost/iterator/function_output_iterator.hpp>
// Type Declarations
typedef Kernel::Point_3 Point;
typedef CGAL::Point_set_3<Point> Point_set;
typedef Point_set::Point_map Point_map;
int main(int argc, char **argv) {
// Point set will be used to hold our points
Point_set points;
// Load points from a file.
std::ifstream stream((argc > 1) ? argv[1] : CGAL::data_file_path("points_3/cube.pwn"));
stream >> points;
if (0 == points.number_of_points()) {
std::cerr << "Error: cannot read file" << std::endl;
return EXIT_FAILURE;
}
std::cout << "loaded " << points.number_of_points() << " points" << std::endl;
// Create an octree from the points
Octree octree(points, points.point_map());
// Build the octree
octree.refine(10, 20);
// Find the nearest points to a few locations
std::vector<Point> points_to_find = {
{0, 0, 0},
{1, 1, 1},
{-1, -1, -1},
{-0.46026, -0.25353, 0.32051},
{-0.460261, -0.253533, 0.320513}
};
for (const Point& p : points_to_find)
octree.nearest_neighbors
(p, 1, // k=1 to find the single closest point
boost::make_function_output_iterator
([&](const Point& nearest)
{
std::cout << "the nearest point to (" << p <<
") is (" << nearest << ")" << std::endl;
}));
return EXIT_SUCCESS;
}