public static Vector3 GetHoverPoint(Vector3 lp1, Vector3 lp2, Vector3 modelP, float attachR)
{
var _area = Geometric.GetArea(lp1, lp2, modelP); //三角形面积
var _lLength = Vector3.Distance(lp1, lp2); //lp1,lp2长度
var dis = _lLength < 1e-3 ? attachR + 1 : 2 * _area / _lLength; //modelP到lp1,lp2的距离
if (dis > attachR) //太远
{
return(default(Vector3));
}
Vector3 lDir = lp1 - lp2; //直线方向
Vector3 mDir = QuaternionUtility.Euler(0, 90, 0) * lDir; //xz平面上垂直直线方向
Vector3 __S = modelP - mDir * 999;
Vector3 __E = modelP + mDir * 999; //临时的两个线点
if (!Geometric.Meet(__S, __E, lp1, lp2)) //不相交
{
return(default(Vector3));
}
//到这里还能执行的话是相交且接近, 就要计算点
Vector3 res = Geometric.GetCorssPointOfSegment(__E, __S, lp1, lp2);
return(res);
}
/// <summary>
/// 使用向量叉乘来计算任意多边形面积
/// </summary>
/// <param name="points">顺序描述的点集</param>
/// <returns>面积</returns>
public static float GetArea(params Vector3[] points)
{
//去重
List <Vector3> toCalcualte = new List <Vector3>(points);
for (int i = 0; i < toCalcualte.Count; i++)
{
for (int j = 0; j < toCalcualte.Count; j++)
{
if (j != i && toCalcualte[i] == toCalcualte[j])
{
toCalcualte.RemoveAt(j);
j--;
}
}
}
int n = toCalcualte.Count;
for (int i = 0; i < n; i++)
{
if (Geometric.Meet(toCalcualte[i], toCalcualte[(i + 1) % n], toCalcualte[(i + 2) % n], toCalcualte[(i + 3) % n]))
{
var temp = toCalcualte[(i + 2) % n];
toCalcualte[(i + 2) % n] = toCalcualte[(i + 1) % n];
toCalcualte[(i + 1) % n] = temp;
}
}
points = toCalcualte.ToArray();
float area = 0f;
Vector3 ANXI = toCalcualte[0] + Vector3.one * 100;//要尽量远来补平舍入误差
for (int i = 0; i < points.Length; i++)
{
area += cross(ANXI, points[i], points[(i + 1) % points.Length]);
}
area /= 2f;
return(Mathf.Abs(area));
}
