以下是實現hud跟隨3D物體的腳本，只是測試用，不是開發中的代碼，腳本掛在任意游戲物體上 demo下載
using UnityEngine;
public class SceneFollowUI : MonoBehaviour
{
public RectTransform hud; //Hud
public RectTransform canvas;//UI的父節點
public Transform parent; //跟隨的3D物體
public Camera uiCamera; //UICamera
Vector3 offset; //hud偏移量
Vector3 cachePoint;
float originalDistance;
float factor = 1;
bool visiable = true;
void Start()
{
offset = hud.localPosition - WorldPointToUILocalPoint(parent.position);
cachePoint = parent.position;
originalDistance = GetCameraHudRootDistance();
UpdateVisible();
}
void LateUpdate()
{
if (cachePoint != parent.position)
{
float curDistance = GetCameraHudRootDistance();
factor = originalDistance / curDistance;
UpdatePosition(); //更新Hud位置
UpdateScale(); //更新Hud的大小
UpdateVisible(); //更新Hud是否可見，根據需求設置：factor或者根據和相機距離設置，一定范圍內可見，相機視野范圍內可見 等等
}
}
private void UpdateVisible()
{
}
private void UpdatePosition()
{
hud.localPosition = WorldPointToUILocalPoint(parent.position) + offset * factor;
cachePoint = parent.position;
}
private void UpdateScale()
{
hud.localScale = Vector3.one * factor;
}
private float GetCameraHudRootDistance()
{
return Vector3.Distance(Camera.main.transform.position, parent.position);
}
private Vector3 WorldPointToUILocalPoint(Vector3 point)
{
Vector3 screenPoint = Camera.main.WorldToScreenPoint(point);
Vector2 localPoint;
RectTransformUtility.ScreenPointToLocalPointInRectangle(canvas, screenPoint, uiCamera, out localPoint);
return localPoint;
}
}