CGAL users discussion list

["J. Scheurich" <>]

Hi,

I am a programmer working on white_dune.
White_dune can now read colored .OFF files, but only if the color are on
vertices, not on Faces.

How to read the face information of .OFF files with CGAL ?

I have the following  test program, but i prints "color do not exist" 8-(

// compile:   g++ -g -O0 readoff.cpp -lCGAL
// test data: http://wdune.ourproject.org/examples/facecube.off
// copy of https://people.sc.fsu.edu/~jburkardt/data/off/facecube.off
without comments
// output:
// $ ./a.out
// facecube.off: Success
// color do not exist

#include <CGAL/Simple_cartesian.h>
typedef CGAL::Simple_cartesian<double> Kernel;
#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/Polygon_mesh_processing/corefinement.h>
#include <CGAL/Polygon_mesh_processing/self_intersections.h>
#include <CGAL/Polygon_mesh_processing/triangulate_faces.h>
#include <CGAL/boost/graph/dijkstra_shortest_paths.h>
#include <CGAL/exceptions.h>
#include <CGAL/IO/Color.h>
#include <boost/graph/prim_minimum_spanning_tree.hpp>
#include <boost/foreach.hpp>
typedef Kernel::Point_3 Point;
typedef CGAL::Surface_mesh<Point> Surface;
typedef CGAL::Surface_mesh<Point> SurfaceMesh;
typedef CGAL::Color Color;
typedef Surface::Vertex_index vertex_index;
typedef boost::graph_traits<Surface>::vertex_descriptor vertex_descriptor;
typedef boost::graph_traits<Surface>::face_descriptor face_descriptor;
typedef boost::graph_traits<Surface>::halfedge_descriptor
halfedge_descriptor;
std::vector<Point> verts;
std::vector<Color> cols;

int main(int argc, char **argv)
{
    const char *filename = "facecube.off";
    std::ifstream input(filename);
    SurfaceMesh *mesh = new SurfaceMesh();

    if (!input || !(input >> *mesh)) {
        perror(filename);
    }

    SurfaceMesh::Property_map<SurfaceMesh::Face_index, CGAL::Color>
vcolors =
        mesh->property_map<SurfaceMesh::Face_index, CGAL::Color >
        ("f:color").first;

    bool colorExists = mesh->property_map
        <SurfaceMesh::Face_index, CGAL::Color>("f:color").second;

    if (colorExists )
        printf("color exists\n");
    else
        printf("color do not exist\n");
}

The amazing thing is the execution of "perror(filename)" even if the
file exists.
It looks like the curŕent OFF reader (CGAL 4.11-2 on Ubuntu 18.04) can
not handle face colors 8-(

so long
MUFFTI