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[たまちゃん <>]

Thanks a lot Sebastien! I added two checks.

if(P.area()>0.0 && Q.area()>0.0)CGAL::intersection (P, Q, std::back_inserter(intR));

Regards,

tamachan

2017-06-22 23:12 GMT+09:00 Sebastien Loriot (GeometryFactory) <>:

If you compile with assertions ON, you'll get some clear errors:

File       : /home/sloriot/CGAL/git/integration/Boolean_set_operations_2/include/CGAL/Boolean_set_operations_2/Gps_polygon_validation.h
Line       : 262
Explanation: The polygon boundary self overlaps.

Your polygons have 0 area are not valid input.

Sebastien.

On 06/22/2017 03:39 PM, たまちゃん wrote:

Hello Everyone,

I am getting an error in CGAL::intersection sometimes. I wrote sample
code below. How do I fix this error?

Thanks in advance!

Regards,
tamachan

Sample code (alwaysdie.cpp):

#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
//#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Boolean_set_operations_2.h>
#include <list>

typedef CGAL::Exact_predicates_exact_constructions_kernel Kernel;
//typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
typedef Kernel::Point_2                                   Point_2;
typedef CGAL::Polygon_2<Kernel>                           Polygon_2;
typedef CGAL::Polygon_with_holes_2<Kernel>
 Polygon_with_holes_2;
typedef std::list<Polygon_with_holes_2>                   Pwh_list_2;

#define SWITCH_Q     2

int main ()
{
  Polygon_2 P;
  P.push_back (Point_2 (0.0, 0.0));
  P.push_back (Point_2 (3.0, 3.0));
  P.push_back (Point_2 (2.0, 2.0));

  Polygon_2 Q;
#if SWITCH_Q==0
  Q.push_back (Point_2 (1.0, 1.0));
  Q.push_back (Point_2 (3.0, 1.0));
  Q.push_back (Point_2 (2.0, 1.0));
#elif SWITCH_Q==1
  Q.push_back (Point_2 (-1.0,2.0));
  Q.push_back (Point_2 (5.0, 2.0));
  Q.push_back (Point_2 (4.0, 2.0));
#else
  Q.push_back (Point_2 (0.0, 0.0));
  Q.push_back (Point_2 (2.0, 2.0));
  Q.push_back (Point_2 (1.0, 1.0));
#endif

  Pwh_list_2                  intR;
  Pwh_list_2::const_iterator  it;

  CGAL::intersection (P, Q, std::back_inserter(intR)); // !!!!!!! <<<
Access Violation here !!!!!!!!!
  return 0;
}

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