CGAL users discussion list

["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;
> }