Segmentation fault during drawing a 3D Nef polyhedron

[alekseYY]

Issue Details

I've tried to draw a 3D Nef polyhedron from the Section 5.6 of the User Manual for the "3D Boolean Operations on Nef Polyhedra" and got the segmentation fault. The problem is in the "draw_nef_3.h" header, function is "compute_elements". Are there any limitations on the input data for drawing?

Source Code

#include <fstream>
#include <iostream>

#define CGAL_USE_BASIC_VIEWER

#include <CGAL/Exact_integer.h>
#include <CGAL/Extended_homogeneous.h>
#include <CGAL/Nef_polyhedron_3.h>
#include <CGAL/IO/Nef_polyhedron_iostream_3.h>
#include <CGAL/draw_nef_3.h>

using Kernel = CGAL::Extended_homogeneous<CGAL::Exact_integer>;
using Nef_polyhedron = CGAL::Nef_polyhedron_3<Kernel>;

int main()
{
  Nef_polyhedron N;
  // ------ the input data correspond to the 'Nef_3/extended_kernel.cpp'
  // ------ example from the Section 5.6 of the User Manual   
  std::ifstream fs("data/extended_kernel.cin");
  if (fs >> N)
  {
    std::cout << "File loaded" << std::endl;
    CGAL::draw(N);
  }
  else
  {
     std::cout << "ERROR!!!" << std::endl;
  }
}

Environment

• Operating system (Windows/Mac/Linux, 32/64 bits): Linux 64-bit
• Compiler: G++ 10.3.0
• Release or debug mode: Debug
• Specific flags used (if any): -no-pie -ggdb -O0
• CGAL version: 5.5.2
• Boost version: 1.71.0
• Other libraries versions if used (Eigen, TBB, etc.): Qt 5.12.8

[gdamiand]

The pach above seems to solve the bug; but maybe with this code, the object is not drawn correctly.

[alekseYY]

In the CGAL 6.0 there are no segmentation fault during drawing. However the picture, corresponding to the file "extended_kernel.cin", looks weird (please see below). It seems to me that the Extended_homogeneous kernel is still a problem for the draw function.