/// <summary>
/// 判断一个点是否在一个区域内
/// </summary>
public class PolyUtil
{
//notice, in the case of point[0] == point[1] == point[2] == point[3]
//this function return false positive...
public static bool Contains(Vector3[] point, Vector3 p)
{
var dp0 = p - point[0];
var dp1 = p - point[1];
var dp2 = p - point[2];
var dp3 = p - point[3];
var cdp01 = Vector3.Cross(dp0, dp1);
var cdp12 = Vector3.Cross(dp1, dp2);
var cdp23 = Vector3.Cross(dp2, dp3);
var cdp30 = Vector3.Cross(dp3, dp0);
return Vector3.Dot(cdp01, cdp12) >= 0 &&
Vector3.Dot(cdp12, cdp23) >= 0 &&
Vector3.Dot(cdp23, cdp30) >= 0;
}
}
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