static function PointOnLineParameter (point : Vector3, linePoint : Vector3, lineDirection : Vector3) : float
Description描述
Returns the parameter for the projection of the point on the given line
返回给定线上投射点的参数。
The return value can be negative if the projected point is in negative lineDirection relative to the linePoint
返回值可以为负数，如果投射点相对于linePoint是负的lineDirection
参见： ProjectPointLine.
