public static Polygon Intersection(Polygon a, Polygon b)
{
b.points.Add(b.points.First());
for (int i = 0; i < b.points.Count - 1; i++)
a = Intersection(a, b.points[i], b.points[i + 1]);
return a;
}
public static Polygon Intersection(Polygon a, Vector b1, Vector b2)
{
List<Vector> result = new List<Vector>();
a.points.Add(a.points.Last());
for (int i = 0; i < a.points.Count - 1; i++)
{
Vector start = a.points[i];
Vector end = a.points[i + 1];
bool s = Vector.PlacePoint(b1, b2, start) >= 0;
bool e = Vector.PlacePoint(b1, b2, end) >= 0;
if (s)
result.Add(start);
if (s ^ e)
result.Add(Vector.CrossingPoint(start, end, b1, b2));
}
return new Polygon(result);
}