[Boost-bugs] [Boost C++ Libraries] #6958: boost::geometry::intersection on two triangles creates self-intersecting polygon

Subject: [Boost-bugs] [Boost C++ Libraries] #6958: boost::geometry::intersection on two triangles creates self-intersecting polygon
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-05-31 19:48:29

#6958: boost::geometry::intersection on two triangles creates self-intersecting
polygon
-------------------------------------+--------------------------------------
 Reporter:  anonymous                |       Owner:  barendgehrels
     Type:  Bugs                     |      Status:  new          
Milestone:  To Be Determined         |   Component:  geometry     
  Version:  Boost Development Trunk  |    Severity:  Problem      
 Keywords:                           |  
-------------------------------------+--------------------------------------
 This program intersects two non-self-intersecting polygons and receives a
 self-intersecting polygon as output.  The expected result was a polygon
 that does not intersect itself.  I tested this on SVN revision 78784, and
 it failed with:

 A
 B
 terminate called after throwing an instance of
 'boost::geometry::overlay_invalid_input_exception'
   what():  Boost.Geometry Overlay invalid input exception
 Aborted

 Thanks!
 Craig

 {{{
 #include <cstdio>
 #include <vector>
 #include <boost/geometry.hpp>
 #include <boost/geometry/geometries/point_xy.hpp>
 #include <boost/geometry/geometries/polygon.hpp>
 #include <boost/geometry/geometries/register/point.hpp>
 #include <boost/geometry/geometries/register/ring.hpp>
 #include <boost/geometry/io/wkt/wkt.hpp>
 #include <boost/geometry/multi/geometries/multi_polygon.hpp>

 typedef boost::geometry::model::d2::point_xy<double> pt;
 typedef boost::geometry::model::polygon<pt> polygon;
 typedef boost::geometry::model::multi_polygon<polygon> multi_polygon;

 int main()
 {
     polygon green, blue;
     multi_polygon output;

     boost::geometry::read_wkt(
         "POLYGON((0.63872330997599124913 0.25963790394761232516 ,"
         " 0.51901482278481125832 0.36860892060212790966 ,"
         " 0.24443514109589159489 0.62663296470418572426 ,"
         " 0.41175117865081167778 0.47178476291601745274 ,"
         " 0.63872330997599124913 0.25963790394761232516))", green);

     boost::geometry::read_wkt(
         "POLYGON((0.52364358028948876367 0.36823021165656988352 ,"
         " 0.7762673462275415659 0.13443113025277850237 ,"
         " 0.59446187055393329146 0.29992923303868185281 ,"
         " 0.52364358028948876367 0.36823021165656988352))",blue);

     boost::geometry::correct(green);
     boost::geometry::correct(blue);
     boost::geometry::detail::overlay::has_self_intersections(green);
     boost::geometry::detail::overlay::has_self_intersections(blue);

     printf("A\n");
     boost::geometry::intersection(green,blue,output);
     printf("B\n");
     boost::geometry::detail::overlay::has_self_intersections(output);
     printf("C\n");

     return 0;
 }
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6958>
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