using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class UIFollow : MonoBehaviour {
    public GameObject heightFollowObj;  //UI跟随的3D物体
    public RectTransform heightUITarget;  //跟随的UI


    public RectTransform uiParenttt;  //移动UI的父物体，因为我的UI直接挂在Canvas下面，所以这里选的是Canvas


    void Start () {	
	}
	
	// Update is called once per frame
	void Update () {
       World2UI(heightFollowObj.transform.position, uiParenttt, heightUITarget);
    }

    //世界坐标转成UI中父节点的坐标, 并设置子节点的位置
    public void World2UI(Vector3 wpos, RectTransform uiParent, RectTransform uiTarget)
    {
        Vector3 spos = Camera.main.WorldToScreenPoint(wpos);  //获取屏幕坐标
        Vector2 vv = new Vector2(spos.x, spos.y);
        Vector2 retPos;
        RectTransformUtility.ScreenPointToLocalPointInRectangle(uiParent, vv, uiParent.GetComponent<Canvas>().worldCamera, out retPos);  //注意这里是UI相机
        uiTarget.anchoredPosition =new Vector2( retPos.x-80, retPos.y);
    }
}

FR：徐海涛（hunk Xu)
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