[Boost-bugs] [Boost C++ Libraries] #7844: bug with unrolling self intersecting polygon

Subject: [Boost-bugs] [Boost C++ Libraries] #7844: bug with unrolling self intersecting polygon
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2013-01-03 09:30:01

#7844: bug with unrolling self intersecting polygon
---------------------------------------------+------------------------------
 Reporter:  rlepere <renaud.lepere@…>        |       Owner:  ljsimons
     Type:  Bugs                             |      Status:  new     
Milestone:  To Be Determined                 |   Component:  polygon 
  Version:  Boost 1.52.0                     |    Severity:  Problem 
 Keywords:                                   |  
---------------------------------------------+------------------------------
 I m tring to remove loops from self intersecting polygon but the following
 example (a triangle A, B, C with some points nearly aligned between B and
 C) fails.  IMHO it sould return a triangle.

 {{{
 #include <boost/polygon/polygon.hpp>
 #include <vector>
 #include <iostream>

 using namespace boost::polygon;
 using namespace std;

 typedef point_data< int > point;
 typedef vector< point > points;
 typedef polygon_set_data< int > polygon_set;
 typedef polygon_with_holes_data< int > polygon_with_holes;
 typedef vector< polygon_with_holes > polygons_with_holes;


 /*
   * A triangle A, B, C with some nearly aligned points between B and C.
   *
   *     A
   *      +
   *      |\
   *      | \
   *       | \
   *       |  \
   *        |  \
   *        |   \
   *        |    \
   *         |    \
   *         |   /-+ C
   *       B +---
   */
 polygon_with_holes MakeRawPolygon()
 {
      points ps;
      ps.push_back(point(-181928106,288346744));    // A
      ps.push_back(point(-15311797,-289428209));    // B
      ps.push_back(point(56093690,-270295166));
      ps.push_back(point(24502047,-278760121));
      ps.push_back(point(57745146,-269852659));
      ps.push_back(point(56791908,-270108078));
      ps.push_back(point(-14613579,-289241121));
      ps.push_back(point(82923673,-263106094));     // C
      polygon_with_holes poly;
      set_points(poly, ps.begin(), ps.end());
      return poly;
 }

 int main()
 {
      polygon_with_holes polygon(MakeRawPolygon());
      polygon_set ps;
      ps.insert(polygon);

      // first unrool
      polygons_with_holes unrolled_polygons;
      ps.get(unrolled_polygons);

      if (unrolled_polygons.size() == 0u) {
          std::cout << "error" << endl;
      }
 }


 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/7844>
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