Raycast 无缘无故返回 null

Question

好的，这么快的问题，我做了一个简单的：

Ray ray;

然后在update()中我做了一个简单的：

ray = Camera.current.ScreenPointToRay(Input.mousePosition);
Debug.Log(Camera.current.ScreenPointToRay(Input.mousePosition));

由于某种原因，在控制台中，debug.log 注册了一个正在投射的射线，而射线只是认为它是空的。

有什么想法吗？

这是 debug.log 输出：

原点：(-0.2, 2.5, 14.8)，方向：(-0.4, 0.5, -0.7)
Unity.engine.Debug:Log(Object)
TankController:Update()（在 Assets/Games/Chisana/Scripts/TankController.cs:136）

这是光线输出：

NullReferenceException：对象引用未设置为对象的实例
TankController.Update()（在 Assets/Games/Chisana/Scripts/TankController.cs:135）

如果我忽略了什么，这里是完整的脚本：

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

public class TankController : MonoBehaviour
{
    Vector3 targetPosition;
    Vector3 lookAtTarget;

    public Vector4 selectedColor;
    public Vector4 deselectedColor;

    Quaternion playerRot;

    public float rotSpeed = 2;
    public float speed = 3;

    bool OneExecution = false;
    int count = 0;

    public bool Moving = false;
    public bool Selected = false;
    public bool UiSelected = false;
    public bool Hovering = false;

    public GameObject UI;
    public BoxCollider HitBox;

    public DoEverything Properties;
    public GameObject childObj;

    public MeshRenderer mrHighlight;

    public PlayerMaster playerMaster;
    int playerMasterTeam;

    SkinnedMeshRenderer[] skinnedMeshRenderersScan;
    public List<SkinnedMeshRenderer> skinnedMeshRenderersList = new List<SkinnedMeshRenderer>();

    Ray ray;
    RaycastHit hit;

    void Start()
    {
        Properties = GetComponentInChildren<DoEverything>(); //Get the DoEverything script

        childObj = Properties.InstancedEntity; //Get the object it will spawn

        if (mrHighlight.enabled != false && mrHighlight != null) //Make sure the highlight isn't enabled and not null
        {
            mrHighlight.enabled = false;
        }

        skinnedMeshRenderersScan = childObj.GetComponentsInChildren<SkinnedMeshRenderer>(); //Looks for all skinned mesh renderers in child object

        foreach (SkinnedMeshRenderer element in skinnedMeshRenderersScan) //For every object it finds
        {
            if (!skinnedMeshRenderersList.Contains(element)) //If it isn't already in this list
            {
                skinnedMeshRenderersList.Add(element); //Add to the list
            }
        }

        playerMasterTeam = playerMaster.Team;
    }

    void LClickRay()
    {

    }

    void RClickRay()
    {

    }

    void OnMouseEnter()
    {
        Hovering = true;
        foreach (SkinnedMeshRenderer element in skinnedMeshRenderersScan) //For every object it finds
        {
            element.material.color = selectedColor;
        }
    }

    void OnMouseExit()
    {
        Hovering = false;
        foreach (SkinnedMeshRenderer element in skinnedMeshRenderersScan) //For every object it finds
        {
            element.material.color = deselectedColor;
        }
    }

    void OnCollisionEnter(Collision collision)
    {
        if (collision.gameObject.tag == "Player")
        {
            Physics.IgnoreCollision(collision.collider, HitBox);
        }
    }

    void Move()
    {
        transform.rotation = Quaternion.Slerp(transform.rotation,
                                                    playerRot,
                                                    rotSpeed * Time.deltaTime);
        transform.position = Vector3.MoveTowards(transform.position,
                                                targetPosition,
                                                speed * Time.deltaTime);

        if (transform.position == targetPosition)
        {
            Moving = false;
        }
    }

    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            LClickRay();
        }
        if (Input.GetMouseButtonDown(1))
        {
            RClickRay();
        }

        if (Moving == true)
        {
            Move();
        }

        ray = Camera.current.ScreenPointToRay(Input.mousePosition);
        Debug.Log(Camera.current.ScreenPointToRay(Input.mousePosition));
    }
}

Answer 1

不要使用Camera.current！

来自API

我们当前渲染的相机，仅用于低级渲染控制（只读）。

大多数情况下，您会想改用Camera.main。 仅在实现以下事件之一时使用此函数：MonoBehaviour.OnRenderImage、MonoBehaviour.OnPreRender、MonoBehaviour.OnPostRender。

---

所以改用Camera.main

第一个启用的相机标记为“MainCamera”（只读）。

另请注意

场景中的主要相机。如果场景中没有这样的相机，则返回 null。此属性在内部使用FindGameObjectsWithTag，并且不缓存结果。如果每帧使用多次，建议缓存Camera.main的返回值。

所以请确保相机被标记为MainScene, aktive 并且你应该只使用它一次来获取参考并重复使用它

private Camera _mainCamera;

private void Awake ()
{
    _mainCamera = Camera.main;

    //Maybe a check
    if(!_mainCamera)
    {
        Debug.LogError("No MainCamera in Scene!");
        enabled = false;
    }
}

void Update()
{
    // ...

    ray = _mainCamera.ScreenPointToRay(Input.mousePosition);
    Debug.Log(ray);
}