Unity 射线 Ray

相关定义：射线以及射线碰撞体结构

　　Ray , RaycastHit , 

ray:就是点跟方向

raycastHit:

       

发射线：1，physics   2，Camera

Ray ray = new Ray(Vector3.zero, Vector3.forward);
        RaycastHit hit = new RaycastHit();
        Physics.Raycast(ray, out hit);
        Camera.main.ScreenPointToRay(new Vector3(2, 2, 2));
        //Camera.main.ViewportPointToRay