CGAL 6.1 - Quadtrees, Octrees, and Orthtrees

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Orthtree/octree_traversal_custom.cpp
#include <fstream>
#include <iostream>
#include <CGAL/Simple_cartesian.h>
#include <CGAL/Octree.h>
#include <CGAL/Orthtree/IO.h>
#include <CGAL/Point_set_3.h>
#include <CGAL/Point_set_3/IO.h>
// Type Declarations
using Kernel = CGAL::Simple_cartesian<double>;
using Point = Kernel::Point_3;
using Point_set = CGAL::Point_set_3<Point>;
using Point_map = Point_set::Point_map;
using Octree = CGAL::Octree<Kernel, Point_set, Point_map>;
template <typename Tree>
struct First_branch_traversal {
using Node_index = typename Tree::Node_index;
const Tree& m_orthtree;
explicit First_branch_traversal(const Tree& orthtree) : m_orthtree(orthtree) {}
Node_index first_index() const {
return m_orthtree.root();
}
std::optional<Node_index> next_index(Node_index n) const {
// Stop when we reach the base of the tree
if (m_orthtree.is_leaf(n))
return {};
// Always descend the first child
return m_orthtree.child(n, 0);
}
};
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\n" << std::endl;
// Create an octree from the points
Octree octree(points, points.point_map());
// Build the octree
octree.refine();
// Print out the first branch using custom traversal
for (auto node: octree.traverse<First_branch_traversal<Octree>>()) {
std::cout << octree.to_string(node) << std::endl;
}
return EXIT_SUCCESS;
}
CGAL::Orthtree
A data structure using an axis-aligned hyperrectangle decomposition of dD space for efficient access ...
Definition: Orthtree.h:117
CGAL::Point_set_3
Kernel::Point_3
CGAL::Octree
Orthtree< Orthtree_traits_point< GeomTraits, PointRange, PointMap, cubic_nodes, 3 > > Octree
Alias that specializes the Orthtree class to a 3D octree storing 3D points.
Definition: Octree.h:38
Kernel
CGAL::Simple_cartesian