Unity3D【脚本】把一个ui物体，对准世界坐标中的物体，可以实现例如血条等

using UnityEngine;
using System.Collections;

public class NewBehaviourScript : MonoBehaviour {

public GameObject TargetObject;		//世界坐标中，需要对准的物体
public Camera worldcamera;			//世界摄像机
public Camera guiCamera;			//ui摄像机
//public GameObject obj;

// Use this for initialization
void Start () {
//
worldcamera = NGUITools.FindCameraForLayer (TargetObject.layer);
guiCamera = NGUITools.FindCameraForLayer (this.gameObject.layer);
}
void Update () {

}
void LateUpdate() {
//世界坐标到ui坐标的转换
Vector3 pos = worldcamera.WorldToScreenPoint (TargetObject.transform.position);
pos = guiCamera.ScreenToWorldPoint (pos);
pos.z = 0;
//改变ui上坐标的时候，C#中不能直接赋值x、y、z的值，需要给一个Vector3
transform.position = pos;
}

}