【Unity学习】实现screen space模式下UI跟踪游戏物体（在 UI 中跟踪和显示任何 Gameobject 位置）

话不多说，直接上代码：

using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

[RequireComponent(typeof(CanvasGroup))]
public class UI_Tracking_Target_Pos : MonoBehaviour
{
    
    
	//目标物体
    public Transform target;
    //UI与目标物体的距离
    public Vector3 offset;
    //当物体不在视图范围内，显示的物体方向图片
    public Image targetOrientation;
    //要赋值给上面Image的上下左右sprite
    public Sprite up_Texture;
    public Sprite down_Texture;
    public Sprite left_Texture;
    public Sprite right_Texture;
	//目标物体的屏幕空间坐标
    private Vector3 targetScreenPos;

    // Update is called once per frame
    void Update()
    {
    
    
        if (!isTargetInView())
        {
    
    
            transform.GetComponent<CanvasGroup>().alpha = 0;
        }
        else
        {
    
    
            transform.GetComponent<CanvasGroup>().alpha = 1;
        }

        targetScreenPos = Camera.main.WorldToScreenPoint(target.position);
        transform.GetComponent<RectTransform>().position = targetScreenPos + offset;
    }

    private bool isTargetInView()
    {
    
    
        Vector3 vec = Camera.main.WorldToViewportPoint(target.position);
        if (vec.x > 0 && vec.x < 1 && vec.y > 0 && vec.y < 1 && vec.z > 0)
        {
    
    
            targetOrientation.transform.SetParent(transform);
            targetOrientation.transform.position = transform.position;
            targetOrientation.transform.GetComponent<CanvasGroup>().alpha = 0;
            //物体的中心的在相机内部
            return true;
        }
        else
        {
    
    
            targetOrientation.transform.SetParent(transform.parent);
            targetOrientation.transform.GetComponent<CanvasGroup>().alpha = 1;

            if (vec.x < 0)
            {
    
    
                targetOrientation.sprite = left_Texture;
                targetOrientation.transform.GetComponent<RectTransform>().pivot = new Vector2(0, 0.5f);
                targetOrientation.transform.position = new Vector3(0, transform.position.y, 0);
            }
            else if (vec.x > 1)
            {
    
    
                targetOrientation.sprite = right_Texture;
                targetOrientation.transform.GetComponent<RectTransform>().pivot = new Vector2(1, 0.5f);
                //canvas scale设置为1920*1080
                targetOrientation.transform.position = new Vector3(1920, transform.position.y, 0);
            }
            else if (vec.y < 0)
            {
    
    
                targetOrientation.sprite = down_Texture;
                targetOrientation.transform.GetComponent<RectTransform>().pivot = new Vector2(0.5f, 0);
                targetOrientation.transform.position = new Vector3(transform.position.x, 0, 0);
            }
            else if (vec.y > 1)
            {
    
    
                targetOrientation.sprite = up_Texture;
                targetOrientation.transform.GetComponent<RectTransform>().pivot = new Vector2(0.5f, 1);
                targetOrientation.transform.position = new Vector3(transform.position.x, 1080, 0);
            }
            return false;
        }
    }
}

Inspector面板配置如下：

效果如下：