/// <summary>
/// 求两个多边形差集
/// </summary>
/// <param name="poly1"></param>
/// <param name="poly2"></param>
/// <param name="interPoly"></param>
/// <returns></returns>
public static bool PolygonClip(List<Vector2> poly1, List<Vector2> poly2, out List<Vector2> interPoly)
{
interPoly = new List<Vector2>();
if (poly1.Count < 3 || poly2.Count < 3)
{
return false;
}
Vector2 point;
//计算多边形交点
for (int i = 0; i < poly1.Count; i++)
{
int poly1_next_idx = (i + 1) % poly1.Count;
for (int j = 0; j < poly2.Count; j++)
{
int poly2_next_idx = (j + 1) % poly2.Count;
if (ImageUtil.GetIntersection(poly1[i], poly1[poly1_next_idx],
poly2[j], poly2[poly2_next_idx],
out point))
{
interPoly.Add(point);
}
}
}
//计算多边形内部点
for (int i = 0; i < poly1.Count; i++)
{
if (ImageUtil.Contains(poly1[i], poly2))
{
interPoly.Add(poly1[i]);
}
}
for (int i = 0; i < poly2.Count; i++)
{
if (ImageUtil.Contains(poly2[i], poly1))
{
interPoly.Add(poly2[i]);
}
}
if (interPoly.Count <= 0)
return false;
//点集排序
interPoly = EdgeUtil.CreateConvexOutside(interPoly);
return true;
}
