[Boost-bugs] [Boost C++ Libraries] #6560: The intersection of these two polygons returns an empty result

Subject: [Boost-bugs] [Boost C++ Libraries] #6560: The intersection of these two polygons returns an empty result
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-02-15 14:36:28

#6560: The intersection of these two polygons returns an empty result
-------------------------------------+--------------------------------------
 Reporter:  anders.jel@…             |       Owner:  ljsimons
     Type:  Bugs                     |      Status:  new     
Milestone:  To Be Determined         |   Component:  polygon 
  Version:  Boost Development Trunk  |    Severity:  Problem 
 Keywords:                           |  
-------------------------------------+--------------------------------------
 This may be related to #5103.

 The following program prints a zero area for the intersection of the two
 polygons.

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

 using namespace boost::polygon;
 using namespace boost::polygon::operators;

 int main()
 {
     typedef point_data<int64_t> point;

     std::vector<point> a;
     a.push_back(point( 50000000000,   50000000000));
     a.push_back(point( 12500000000,   50000000000));
     a.push_back(point(           0,  100000000000));
     a.push_back(point(-12500000000,   50000000000));
     a.push_back(point(-50000000000,   50000000000));
     a.push_back(point(-50000000000,  -50000000000));
     a.push_back(point(-37500000000,  -50000000000));
     a.push_back(point(-50000000000, -100000000000));
     a.push_back(point( 50000000000, -100000000000));
     a.push_back(point( 37500000000,  -50000000000));
     a.push_back(point( 50000000000,  -50000000000));
     a.push_back(point( 50000000000,   50000000000));

     polygon_data<int64_t> polygon_a;
     set_points(polygon_a, a.begin(), a.end());

     std::vector<point> b;
     b.push_back(point(-47702617860,   50000000000));
     b.push_back(point( 50000000000,   50000000000));
     b.push_back(point( 50000000000,  -88753775284));
     b.push_back(point(-47702617860,  -88753775284));

     polygon_data<int64_t> polygon_b;
     set_points(polygon_b, b.begin(), b.end());

     polygon_set_data<int64_t> intersection = polygon_a * polygon_b;
     std::cout << area(intersection) << std::endl; // Prints 0

     std::vector<polygon_data<int64_t> > polygons_in_intersection;
     intersection.get(polygons_in_intersection);
     std::cout << polygons_in_intersection.size() << std::endl; // Prints 0

     return 0;
 }
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6560>
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