CGAL users discussion list

[Claus Volko <>]

I'm now trying this variant:

CGAL::Surface_mesh<Point_3> create_tree()
{
    using Mesh = CGAL::Surface_mesh<Point_3>;
    Mesh mesh;
    CGAL::copy_face_graph(polygon_mesh, mesh);
    Tree tree(faces(mesh).first, faces(mesh).second, mesh);
        std::vector<Point_3> points;
        for (auto x = -1000; x < +1000; x++)
            for (auto z = -1000; z < +1000; z++)
            {
                Point_3 point(x, +20, z);
                points.push_back(point);
                Point_3 point1(x, -10, z);
                Line_3 line(point, point1);
                Ray ray(point, line);
                auto intersection = tree.first_intersection(ray);
                if (intersection)
                {
                    const Point_3* p = boost::get<Point_3>(&(intersection->first));
                    if (p) points.push_back(*p);
                }
            }

        CGAL::Surface_mesh<Point_3> output_mesh;

        std::string fname = "c:\\temp\\newmesh.xyz";
        CGAL::IO::write_XYZ(fname, points);

        Point_set points1;
        std::ifstream stream(fname, std::ios_base::binary);
        stream >> points1;

        std::cout << "Reconstructing surface" << std::endl;

        typedef std::array<std::size_t, 3> Facet; // Triple of indices
        std::vector<Facet> facets;
        // The function is called using directly the points raw iterators
        CGAL::advancing_front_surface_reconstruction(points1.points().begin(),
            points1.points().end(),
            std::back_inserter(facets));
        std::cout << facets.size()
            << " facet(s) generated by reconstruction." << std::endl;
        // copy points for random access
        std::vector<Point_3> vertices;
        vertices.reserve(points1.size());
        std::copy(points1.points().begin(), points1.points().end(), std::back_inserter(vertices));
        CGAL::Polygon_mesh_processing::polygon_soup_to_polygon_mesh(vertices, facets, output_mesh);

        std::cout << "Returning output mesh" << std::endl;
    return output_mesh;
}

It seems that these two lines are not working if I compile as DLL:

auto intersection = tree.first_intersection(ray);

CGAL::advancing_front_surface_reconstruction(points1.points().begin(), points1.points().end(), std::back_inserter(facets));

Am Do., 12. Okt. 2023 um 09:14 Uhr schrieb Claus Volko <>:

I also tried this instead of Delaunay_triangulation_2, but it seems to hang (no progress for more than 20 minutes).

Polyhedron create_tree()
{
    using Mesh = CGAL::Surface_mesh<Point_3>;
    Mesh mesh;
    CGAL::copy_face_graph(polygon_mesh, mesh);
    Tree tree(faces(mesh).first, faces(mesh).second, mesh);

    std::vector<Point_3> points;
    for (double x = -1000; x < +1000; x++)
        for (double z = -1000; z < +1000; z++)
        {
            Point_3 point(x, +20, z);
            Point_3 point1(x, -10, z);
            Line_3 line(point, point1);
            Ray ray(point, line);
            auto intersection = tree.first_intersection(ray);
            if (intersection)
            {
                const Point_3* p = boost::get<Point_3>(&(intersection->first));
                if (p) points.push_back(*p);
            }
        }

    CGAL::IO::write_XYZ("c:\\temp\\newmesh.xyz", points);

    std::vector<Pwn> points1;
    CGAL::IO::read_points("c:\\temp\\newmesh.xyz", std::back_inserter(points1),
        CGAL::parameters::point_map(CGAL::First_of_pair_property_map<Pwn>())
        .normal_map(CGAL::Second_of_pair_property_map<Pwn>()));
    double average_spacing = CGAL::compute_average_spacing<CGAL::Sequential_tag>
        (points1, 6, CGAL::parameters::point_map(CGAL::First_of_pair_property_map<Pwn>()));

    std::cout << "Reconstructing poisson surface" << std::endl;

    Polyhedron output_mesh;
    CGAL::poisson_surface_reconstruction_delaunay
    (points1.begin(), points1.end(),
        CGAL::First_of_pair_property_map<Pwn>(),
        CGAL::Second_of_pair_property_map<Pwn>(),
        output_mesh, average_spacing);

    std::cout << "Returning output mesh" << std::endl;

    return output_mesh;
}

Am Do., 12. Okt. 2023 um 06:42 Uhr schrieb Claus Volko <>:

I attached the code I am trying to compile. When compiling it as EXE it works but not as DLL. The problem seems to be related to the code line where I define a TIN (using Delaunay_triangulation_2). When I include the DLL in a C# project and call region_growing_algorithm from there, I get the error message "Module not found". This does not happen when I outcomment USE_TREE. What's wrong with TIN?

--

Dipl.-Ing. Dr. Claus D. Volko, BSc
http://www.cdvolko.net/

--

Dipl.-Ing. Dr. Claus D. Volko, BSc
http://www.cdvolko.net/

--

Dipl.-Ing. Dr. Claus D. Volko, BSc
http://www.cdvolko.net/