简介
游戏中经常会需要实现屏幕外标记指示的功能,这样能方便玩家快速定位目标方位,尤其在多人网络游戏中出现(守望先锋,彩虹六号,Apex英雄等等):
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具体实现
现在使用Unity实现,其实要复杂可以很复杂,这里肯定用简单直接点的,核心功能是Unity的Unity - Scripting API: Camera.WorldToScreenPoint (unity3d.com)https://docs.unity3d.com/ScriptReference/Camera.WorldToScreenPoint.html
这个API可以直接将特定物体在屏幕上的相对坐标输出出来,真是非常Nice!
在Unity Canvas中加入一个Image便可,箭头的话放入子集,可能需要一个空物体做parent来当作旋转轴心,然后在Canvas组件中加入如下脚本,然后在Unity中指定每个变量。部分解析在代码注释中,不保证是最佳解决方法,但是确实能用。
using UnityEngine;
/*
* Copyright (c) [2023] [Lizhneghe.Chen https://github.com/Lizhenghe-Chen]
*/
//https://blog.csdn.net/DUYIJIU/article/details/98366918
//https://indienova.com/indie-game-development/unity-off-screen-objective-marker/
public class TargetToScreen : MonoBehaviour
{
[Header("Assign below variables in the inspector:")]
[SerializeField] Transform TargetTransform;
[SerializeField] Vector3 TargetPositionOffset = new Vector3(0, 1, 0);
[SerializeField] float screenBoundOffset = 0.1f;
[SerializeField] RectTransform TargetImage, TargetImageArrow;
[SerializeField] TMPro.TextMeshProUGUI TargetText;
[Header("Below is for Debug use:")]
[SerializeField] Vector3 screenPosition, screenBound;
[SerializeField] Vector2 Arrowdirection;
private void LateUpdate()
{
TargetToScreenPosition();
}
/// <summary>
/// This function is to convert the world position of the target to the screen position, and then update the position of the target image and the arrow image.
/// </summary>
public void TargetToScreenPosition()
{
screenPosition = Camera.main.WorldToScreenPoint(TargetTransform.position + TargetPositionOffset);// simple way to get the screen position of the target
(screenBound.x, screenBound.y) = (Screen.width, Screen.height);//get the screen size
if (screenPosition.z < 0)//if the target is behind the camera, flip the screen position
{
screenPosition = -screenPosition;
if (screenPosition.y > screenBound.y / 2)//this is to avoid small probablity that the target is behind the camera and the screen position is flipped, but the y position is still in the screen
{
screenPosition.y = screenBound.y;
}
else screenPosition.y = 0;
}
//clamp the screen position to the screen bound
TargetImage.transform.position = new Vector2(
Mathf.Clamp(screenPosition.x, screenBound.y * screenBoundOffset, screenBound.x - screenBound.y * screenBoundOffset),
Mathf.Clamp(screenPosition.y, screenBound.y * screenBoundOffset, screenBound.y - screenBound.y * screenBoundOffset)
);
//optional, rotate the arrow to point to the target:
Arrowdirection = TargetImageArrow.transform.position - screenPosition;//get the direction of the arrow by subtracting the screen position of the target from the screen position of the arrow
// Debug.Log(Arrowdirection.magnitude);
if (Mathf.Abs(Arrowdirection.x + Arrowdirection.y) < 0.1)
{
//disable the arrow when the target is too close to the center of the screen
TargetImageArrow.gameObject.SetActive(false);
//TargetImageArrow.transform.up = Vector2.zero;
}
else
{
TargetImageArrow.gameObject.SetActive(true);
TargetImageArrow.transform.up = Arrowdirection;
}
//optional, update the distance text
TargetText.text = Vector3.Distance(TargetTransform.position, Camera.main.transform.position).ToString("F1") + "m";
}
}