var outHitAllInfo:Vector.<RaycastHit> = new Vector.<RaycastHit>();
point.elements[0] = MouseManager.instance.mouseX;
point.elements[1] = MouseManager.instance.mouseY;
ray.direction.x = 0;
ray.direction.y = 0;
ray.direction.z = 0;
ray.origin.x = 0;
ray.origin.y = 0;
ray.origin.z = 0;
handCamera.viewportPointToRay(point, ray);
Physics.rayCastAll(ray, outHitAllInfo);
var hit:RaycastHit = outHitAllInfo[0];
一直无法获得正确的点击对象，后来发现获得了多个碰撞对象，其中第一个是一个parent为null的sprite3D对象
