CGAL users discussion list

[Gillian Ng <>]

I'm just trying to find out if two polygons intersect. However it gives this
error, which seems odd... I'm using CGAL 3.6.1 with Visual Studio .NET 2005.

----------
CGAL error: precondition violation!
Expression : ! _predP->is_valid() || comp_f(object, _predP->object) !=
SMALLER
File       : d:\libs\cgal_vc8\include\cgal\multiset.h
Line       : 2142
Explanation:
Refer to the bug-reporting instructions at
http://www.cgal.org/bug_report.html
----------

This is the code I wrote:

----------
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Polygon_2 <K> Polygon_2;

bool DoPolygonsIntersect( Polygon_2 &p1, Polygon_2 &p2 )
{
        if ( CGAL::do_overlap( p1.bbox(), p2.bbox() ) )
        {
                if ( CGAL::do_intersect( p1, p2 ) )
                {
                        return true;
                }
        }

        return false;
}
----------

Please help! Thanks a lot guys. 

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