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#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
#include <CGAL/Polyhedron_3.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/Nef_polyhedron_3.h>
#include <CGAL/boost/graph/convert_nef_polyhedron_to_polygon_mesh.h>
#include <iostream>
#include <sstream>
#include <fstream>
typedef CGAL::Exact_predicates_exact_constructions_kernel Exact_kernel;
typedef CGAL::Polyhedron_3<Exact_kernel> Polyhedron;
typedef CGAL::Surface_mesh<Exact_kernel::Point_3> Surface_mesh;
typedef CGAL::Nef_polyhedron_3<Exact_kernel> Nef_polyhedron;
void fill_cube_1(Polyhedron& poly)
{
std::string input =
"OFF\n\
8 12 0\n\
-1 -1 -1\n\
-1 1 -1\n\
1 1 -1\n\
1 -1 -1\n\
-1 -1 1\n\
-1 1 1\n\
1 1 1\n\
1 -1 1\n\
3 0 1 3\n\
3 3 1 2\n\
3 0 4 1\n\
3 1 4 5\n\
3 3 2 7\n\
3 7 2 6\n\
3 4 0 3\n\
3 7 4 3\n\
3 6 4 7\n\
3 6 5 4\n\
3 1 5 6\n\
3 2 1 6";
std::stringstream ss;
ss << input;
ss >> poly;
}
void fill_cube_2(Polyhedron& poly)
{
std::string input =
"OFF\n\
8 12 0\n\
-0.5 -0.5 -0.5\n\
-0.5 0.5 -0.5\n\
0.5 0.5 -0.5\n\
0.5 -0.5 -0.5\n\
-0.5 -0.5 0.5\n\
-0.5 0.5 0.5\n\
0.5 0.5 0.5\n\
0.5 -0.5 0.5\n\
3 0 1 3\n\
3 3 1 2\n\
3 0 4 1\n\
3 1 4 5\n\
3 3 2 7\n\
3 7 2 6\n\
3 4 0 3\n\
3 7 4 3\n\
3 6 4 7\n\
3 6 5 4\n\
3 1 5 6\n\
3 2 1 6";
std::stringstream ss;
ss << input;
ss >> poly;
}
int main()
{
// create two nested cubes
Polyhedron cube1, cube2;
fill_cube_1(cube1);
fill_cube_2(cube2);
Nef_polyhedron nef1(cube1);
Nef_polyhedron nef2(cube2);
// compute the difference of the nested cubes
Nef_polyhedron nef=nef1-nef2;
// output the result into a Surface_mesh
Surface_mesh output;
CGAL::convert_nef_polyhedron_to_polygon_mesh(nef, output);
std::ofstream out;
out.open("out.off");
out << output;
out.close();
}
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