using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class FollowingUI : MonoBehaviour
{
public Canvas canvas;
public GameObject target;
private Camera uiCamera;
void Start()
{
if(canvas == null || target ==null)
{
Debug.LogError("FollowingUI: No canvas!");
return;
}
if (canvas.renderMode == RenderMode.ScreenSpaceCamera
|| canvas.renderMode == RenderMode.WorldSpace)
{
uiCamera = canvas.worldCamera;
}
else if (canvas.renderMode == RenderMode.ScreenSpaceOverlay)
{
uiCamera = null;
}
}
// Update is called once per frame
void Update()
{
if (canvas == null || target == null)
{
Debug.LogError("FollowingUI: No params!");
return;
}
Vector3 uiPoint = WorldPointToUIPoint(target);
transform.position = uiPoint;
}
private Vector3 WorldPointToUIPoint(GameObject gameObject)
{
//world to screen
Vector2 screenPoint = WorldPointToScreenPoint(gameObject.transform.position);
//screen to ui
// 将屏幕坐标转换为 UI transform.position
RectTransform rt = this.gameObject.GetComponent<RectTransform>();
Vector3 uiPoint = ScreenPointToUIPoint(rt, screenPoint);
return uiPoint;
}
/// <summary>
/// 世界坐标转换为屏幕坐标
/// </summary>
/// <param name="worldPoint">屏幕坐标</param>
/// <returns></returns>
public Vector2 WorldPointToScreenPoint(Vector3 worldPoint)
{
// Camera.main 世界摄像机
Vector2 screenPoint = Camera.main.WorldToScreenPoint(worldPoint);
return screenPoint;
}
/// <summary>
/// 屏幕坐标转换为世界坐标
/// </summary>
/// <param name="screenPoint">屏幕坐标</param>
/// <param name="planeZ">距离摄像机 Z 平面的距离</param>
/// <returns></returns>
public static Vector3 ScreenPointToWorldPoint(Vector2 screenPoint, float planeZ)
{
// Camera.main 世界摄像机
Vector3 position = new Vector3(screenPoint.x, screenPoint.y, planeZ);
Vector3 worldPoint = Camera.main.ScreenToWorldPoint(position);
return worldPoint;
}
// RectTransformUtility.WorldToScreenPoint
// RectTransformUtility.ScreenPointToWorldPointInRectangle
// RectTransformUtility.ScreenPointToLocalPointInRectangle
// 上面三个坐标转换的方法使用 Camera 的地方
// 当 Canvas renderMode 为 RenderMode.ScreenSpaceCamera、RenderMode.WorldSpace 时 传递参数 canvas.worldCamera
// 当 Canvas renderMode 为 RenderMode.ScreenSpaceOverlay 时 传递参数 null
// UI 坐标转换为屏幕坐标
public Vector2 UIPointToScreenPoint(Vector3 worldPoint)
{
// RectTransform：target
// worldPoint = target.position;
Vector2 screenPoint = RectTransformUtility.WorldToScreenPoint(uiCamera, worldPoint);
return screenPoint;
}
// 屏幕坐标转换为 UGUI 坐标
public Vector3 ScreenPointToUIPoint(RectTransform rt, Vector2 screenPoint)
{
Vector3 globalMousePos;
// 当 Canvas renderMode 为 RenderMode.ScreenSpaceCamera、RenderMode.WorldSpace 时 uiCamera 不能为空
// 当 Canvas renderMode 为 RenderMode.ScreenSpaceOverlay 时 uiCamera 可以为空
RectTransformUtility.ScreenPointToWorldPointInRectangle(rt, screenPoint, uiCamera, out globalMousePos);
// 转换后的 globalMousePos 使用下面方法赋值
// target 为需要使用的 UI RectTransform
// rt 可以是 target.GetComponent<RectTransform>(), 也可以是 target.parent.GetComponent<RectTransform>()
// target.transform.position = globalMousePos;
return globalMousePos;
}
// 屏幕坐标转换为 UGUI RectTransform 的 anchoredPosition
public Vector2 ScreenPointToUILocalPoint(RectTransform parentRT, Vector2 screenPoint)
{
Vector2 localPos;
RectTransformUtility.ScreenPointToLocalPointInRectangle(parentRT, screenPoint, uiCamera, out localPos);
// 转换后的 localPos 使用下面方法赋值
// target 为需要使用的 UI RectTransform
// parentRT 是 target.parent.GetComponent<RectTransform>()
// 最后赋值 target.anchoredPosition = localPos;
return localPos;
}
}
https://blog.csdn.net/LIQIANGEASTSUN/article/details/124413387
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