Testing union function of boost::geometry

testggl.cpp

#include <iostream>
#include <string>
using namespace std;

// boost::geometry
#include <boost/geometry.hpp>
#include <boost/geometry/algorithms/intersection.hpp>
#include <boost/geometry/geometries/geometries.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
typedef boost::geometry::model::d2::point_xy<double> Point; 
typedef boost::geometry::model::linestring<Point> Linestring;
typedef boost::geometry::model::polygon<Point> Polygon;
typedef boost::geometry::model::multi_polygon<Polygon> MultiPolygon;
typedef boost::geometry::model::multi_linestring<Linestring> MultiLinestring;

namespace bg = boost::geometry;

void RandomPoly(Polygon &out)
{
	double x = rand() % 10000 / 100.0;
	double y = rand() % 10000 / 100.0;
	int n = 3 + rand() % 50;
	out.clear();
	
	for(int i=0; i<n; i++)
	{
		double ang = (double)i * (M_PI * 2.0) / (double)n;
		double dist = 10.0 + rand() % 10000 / 100.0;
		Point pt(x+dist*cos(ang), y-dist*sin(ang));
		//cout << ang << "," << pt.x() << "," << pt.y() << "," << atan2(pt.y(), pt.x()) << endl;
		bg::append(out.outer(), pt);
	}
	bg::append(out.outer(), out.outer()[0]);
}

int main()
{
	MultiPolygon mp1;
	mp1.resize(1);
	RandomPoly(mp1[0]);
	string reason;
	if(!bg::is_valid(mp1, reason))
	{
		cout << reason << endl;
		exit(0);
	}

	int64_t count = 0;
	while(true)
	{	
		MultiPolygon mp2;
		mp2.resize(1);
		RandomPoly(mp2[0]);
		if(!bg::is_valid(mp2, reason))
		{
			cout << "Error creating polygon:" << reason << endl;
			bg::correct(mp2);
			if(!bg::is_valid(mp2, reason))
			{
				cout << "Failed to correct" << endl;
				exit(0);
			}
		}

		MultiPolygon gTmp;
		bg::union_(mp1, mp2, gTmp);
		mp1 = gTmp;

		if(!bg::is_valid(mp1, reason))
		{
			cout << "Error performing union:" << reason << endl;
			bg::correct(mp1);
			if(!bg::is_valid(mp1, reason))
			{
				cout << "Failed to correct" << endl;
				exit(0);
			}
		}

		count ++;

		if(count%100==0)
		{
			//Reset current state
			mp1.resize(1);
			RandomPoly(mp1[0]);
		}
	}	

}