首页 > 代码库 > 判断两条线段是否相交
判断两条线段是否相交
之前一篇文章里写了一种差乘判断方法:http://www.cnblogs.com/hont/p/6105997.html
bool IsIntersection(Vector3 a, Vector3 b, Vector3 c, Vector3 d) { var crossA = Mathf.Sign(Vector3.Cross(d - c, a - c).y); var crossB = Mathf.Sign(Vector3.Cross(d - c, b - c).y); if (crossA == crossB) return false; var crossC = Mathf.Sign(Vector3.Cross(b - a, c - a).y); var crossD = Mathf.Sign(Vector3.Cross(b - a, d - a).y); if (crossC == crossD) return false; return true; }
我也找到了另一个封装好的函数,不仅可以判断相交而且能查到是否相交于虚交点,是否平行等等。
原版是java写的,但出处不详
以下是我修改的Unity版本:
public static int GetIntersection(Vector3 a, Vector3 b, Vector3 c, Vector3 d, out Vector3 contractPoint) { contractPoint = new Vector3(0, 0); if (Mathf.Abs(b.z - a.z) + Mathf.Abs(b.x - a.x) + Mathf.Abs(d.z - c.z) + Mathf.Abs(d.x - c.x) == 0) { if ((c.x - a.x) + (c.z - a.z) == 0) { //Debug.Log("ABCD是同一个点!"); } else { //Debug.Log("AB是一个点,CD是一个点,且AC不同!"); } return 0; } if (Mathf.Abs(b.z - a.z) + Mathf.Abs(b.x - a.x) == 0) { if ((a.x - d.x) * (c.z - d.z) - (a.z - d.z) * (c.x - d.x) == 0) { //Debug.Log("A、B是一个点,且在CD线段上!"); } else { //Debug.Log("A、B是一个点,且不在CD线段上!"); } return 0; } if (Mathf.Abs(d.z - c.z) + Mathf.Abs(d.x - c.x) == 0) { if ((d.x - b.x) * (a.z - b.z) - (d.z - b.z) * (a.x - b.x) == 0) { //Debug.Log("C、D是一个点,且在AB线段上!"); } else { //Debug.Log("C、D是一个点,且不在AB线段上!"); } return 0; } if ((b.z - a.z) * (c.x - d.x) - (b.x - a.x) * (c.z - d.z) == 0) { //Debug.Log("线段平行,无交点!"); return 0; } contractPoint.x = ((b.x - a.x) * (c.x - d.x) * (c.z - a.z) - c.x * (b.x - a.x) * (c.z - d.z) + a.x * (b.z - a.z) * (c.x - d.x)) / ((b.z - a.z) * (c.x - d.x) - (b.x - a.x) * (c.z - d.z)); contractPoint.z = ((b.z - a.z) * (c.z - d.z) * (c.x - a.x) - c.z * (b.z - a.z) * (c.x - d.x) + a.z * (b.x - a.x) * (c.z - d.z)) / ((b.x - a.x) * (c.z - d.z) - (b.z - a.z) * (c.x - d.x)); if ((contractPoint.x - a.x) * (contractPoint.x - b.x) <= 0 && (contractPoint.x - c.x) * (contractPoint.x - d.x) <= 0 && (contractPoint.z - a.z) * (contractPoint.z - b.z) <= 0 && (contractPoint.z - c.z) * (contractPoint.z - d.z) <= 0) { //Debug.Log("线段相交于点(" + contractPoint.x + "," + contractPoint.z + ")!"); return 1; // ‘相交 } else { //Debug.Log("线段相交于虚交点(" + contractPoint.x + "," + contractPoint.z + ")!"); return -1; // ‘相交但不在线段上 } }
判断两条线段是否相交
声明:以上内容来自用户投稿及互联网公开渠道收集整理发布,本网站不拥有所有权,未作人工编辑处理,也不承担相关法律责任,若内容有误或涉及侵权可进行投诉: 投诉/举报 工作人员会在5个工作日内联系你,一经查实,本站将立刻删除涉嫌侵权内容。