#include <cassert>
#include <iostream>
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Weffc++"
#pragma GCC diagnostic ignored "-Wunused-local-typedefs"
#pragma GCC diagnostic ignored "-Wunused-variable"
#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
#pragma GCC diagnostic pop
bool IsConvex(boost::geometry::model::polygon<boost::geometry::model::d2::point_xy<double>> polygon)
{
boost::geometry::correct(polygon);
boost::geometry::model::polygon<boost::geometry::model::d2::point_xy<double>> hull;
boost::geometry::convex_hull(polygon, hull);
return boost::geometry::area(hull) == boost::geometry::area(polygon);
}
int main()
{
typedef boost::geometry::model::d2::point_xy<double> Coordinat2D;
/* Polygons used:
0123456789012 0123456789012
0+------------ 0+------------
1| 1|
2| A---------B 2| A---------B
3| E / 3| \ D /
4| \ / 4| \ / \ /
5| D----C 5| E C
| |
Convex Concave
*/
//Convex shape
{
const std::vector<Coordinat2D> points {
{ 2.0, 2.0}, //A
{12.0, 2.0}, //B
{ 9.0, 5.0}, //C
{ 4.0, 5.0}, //D
{ 2.0, 3.0} //E
};
boost::geometry::model::polygon<Coordinat2D> polygon;
boost::geometry::append(polygon, points);
assert(IsConvex(polygon));
}
//Concave shape
{
const std::vector<Coordinat2D> points {
{ 2.0, 2.0}, //A
{12.0, 2.0}, //B
{ 9.0, 5.0}, //C
{ 7.0, 3.0}, //D
{ 5.0, 5.0} //E
};
boost::geometry::model::polygon<Coordinat2D> polygon;
boost::geometry::append(polygon, points);
assert(!IsConvex(polygon));
}
}
|
