Boost C++ Libraries: Ticket #5103: Boost Polygon: The union of these two polygon return an empty result.

attachment set

thai@… — Thu, 20 Jan 2011 21:11:39 GMT

attachment → TestBoost.Bug.cpp

show the union of these two polygon will return an empty result

status changed; resolution set

Lucanus Simonson — Wed, 19 Sep 2012 00:35:37 GMT

status new → closed
resolution → worksforme

This was apparently fixed a very long time ago or never a problem. My result: union Polygon 1: (-92810838,3618230) (-93203268,4010660) (-94999048,2214880) (-94999302,2214626) (-94999292,2214615) (-95165164,2033778) (-95314770,1838706) (-95446850,1631442) (-95560388,1413510) (-95654368,1186434) (-95728282,951992) (-95781368,711962) (-95813626,468376) (-95824294,222758) (-95269304,222758) (-95260668,419862) (-95234760,615696) (-95192088,808228) (-95132906,996442) (-95057214,1178814) (-94966028,1354074) (-94860110,1520444) (-94739968,1676908) (-94606618,1822450) (-92810838,3618230)

status, version changed; resolution deleted

vvolosyuk@… — Mon, 29 Jul 2013 15:30:56 GMT

status closed → reopened
version Boost 1.45.0 → Boost 1.53.0
resolution worksforme

attachment set

vvolosyuk@… — Mon, 29 Jul 2013 15:38:06 GMT

attachment → Boost crash reproducer.zip

This project illustrates the problem I noticed working with BOOST:Polygon. It does two union operations: the first union should join two overlapping CCW directed polygons, but results into an empty polygons. This operation uses a polygon received after a couple of boost polygon union operations. I did some clean up work on it to remove extra segments that looks like cuts. If I use the polygon without cleaning the union results in crash (the second polygon union call)

z@… — Thu, 06 Feb 2014 20:07:05 GMT

I just want to follow up with this bug and add a simple test program (see below) that demonstrates that union of two polygons returns empty result.

Please note polygon A is a 45 degree and polygon B is an arbitrary with near 45 degree edge. I suspect that failure of polygon union has something to do with union of 45 degree polygon with a abutting arbitrary polygon that has near 45 degree edge. I also include an alternative polygon that has abutting near 45 degree edge and union of them seems to work. So the only difference between alternative and the original polygon is y-coordinate value of one of vertexes that has changed from 2214626 to 2214625.

#include <vector>
#include <boost/polygon/polygon.hpp>
using namespace boost::polygon::operators;
#define POLYGON_45
#ifdef POLYGON_45
int points_A_1[] =
{ // 45 degree polygon
               -92810838,3618230,
               -94606872,1822196,
               -94999302,2214626,
               -93203268,4010660};
int points_A_1_size =4;
#else
int points_A_1[] =
{ // arbitrary polygon
               -92810838,3618230,
               -94606872,1822196,
               -94999302,2214625, // 2214626 -> 2214625, near 45 degree edge
               -93203268,4010660};
int points_A_1_size =4;
#endif
int points_B_1[] =
{
               -94739968,1676908,
               -94606618,1822450,
               -94999048,2214880,
               -95165164,2033778};
int points_B_1_size =4;
int
main(int argc, char **argv)
{
    typedef boost::polygon::polygon_data<int>         Polygon;
    typedef boost::polygon::point_data<int>           Point;
    typedef boost::polygon::polygon_set_data<int>     PolygonSet;
    std::vector<Point> points;
    int count = points_A_1_size;
    for (int i = 0; i < count; ++i) {
        points.push_back(boost::polygon::construct<Point>(points_A_1[2 * i], points_A_1[2 * i+1]));
    }
    Polygon A;
    A.set(points.begin(), points.end());
    points.clear();
    count = points_B_1_size;
    for (int i = 0; i < count; ++i) {
        points.push_back(boost::polygon::construct<Point>(points_B_1[2 * i], points_B_1[2 * i+1]));
    }
    Polygon B;
    B.set(points.begin(), points.end());
    PolygonSet ps1, ps2, ps3;
    ps1 += A;
    ps2 += B;
    assign(ps3, ps1 + ps2);
    std::vector<Polygon> polygons;
    ps3.get(polygons);
    return 0;
}

attachment set

z@… — Thu, 06 Feb 2014 23:59:09 GMT

attachment → Poly_test.cpp

simple test program that shows union of two polygons fails to return anything

Andrii Sydorchuk — Thu, 08 May 2014 00:16:00 GMT

Thank you for your report. I was not able to reproduce the issue in neither of 3 reports.
Could you provide the compiler prompt and Boost libraries version?

owner, status changed

Andrii Sydorchuk — Thu, 08 May 2014 20:54:06 GMT

owner changed from Lucanus Simonson to Andrii Sydorchuk
status reopened → new

mhilferink@… — Thu, 02 Jul 2015 14:04:08 GMT

This issue could have a similar cause as issue 11415. Was the compiler of the Reporter also MSVC?