Question

大约3小时前，我刚刚开始通过YouTube上的Brackeys开设的“如何制作2D游戏”课程开始学习Unity 2D。我在Ubuntu 18.04上使用Unity 2018.4.1f1，因为我的版本不支持JS，所以我必须改用C＃。但是我在第三个视频上遇到了这个错误：GameSetup的变量mainCam尚未分配。这是我在C＃中的代码：

GameSetup.cs

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

public class GameSetup : MonoBehaviour
{
    public Camera mainCam;

    public BoxCollider2D topWall, bottomWall, leftWall, rightWall;

    public Transform Player1, Player2;

    // Start is called before the first frame update
    void Start()
    {
        // topWall = GetComponent<BoxCollider2D>();
        // mainCam = GetComponent<Camera>();
        // If I uncomment this, there would be a new error: There is no 'Camera' attached to '_GM' game object, but a script is trying to access it.
    }

    // Update is called once per frame
    void Update()
    {
        // Move each wall to its edge location
        topWall.size = new Vector2(mainCam.ScreenToWorldPoint(new Vector3(Screen.width * 2.0f, 0f)).x, 1.0f);
        topWall.offset = new Vector2(0f, mainCam.ScreenToWorldPoint(new Vector3(0f, Screen.width, 0f)).y + 0.5f);
    }
}

在Google的帮助下，我从下面的第二个视频的脚本中的rb2d.GetComponent<Rigibody2D>()中添加了Start()，并防止了错误（视频中没有Start()）< / p>

PlayerControls.cs


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


public class PlayerControls : MonoBehaviour
{

    public KeyCode moveUp, moveDown;

    public float speed = 10;

    private Rigidbody2D rb2d = new Rigidbody2D();
    // Start is called before the first frame update
    void Start()
    {
        rb2d = GetComponent<Rigidbody2D>();
    }

    // Update is called once per frame
    void Update()
    {
        if (Input.GetKey(moveUp))
        {
            Vector3 v = rb2d.velocity;
            v.y = speed;
            rb2d.velocity = v;
            // rb2d.velocity.y = speed;
        }
        else if (Input.GetKey(moveDown))
        {
            Vector3 v = rb2d.velocity;
            v.y = speed * (-1);
            rb2d.velocity = v;
        }
        else
        {
            Vector3 v = rb2d.velocity;
            v.y = 0;
            rb2d.velocity = v;
        }
    }
}

如何修复GameSetup.cs中的错误？我完全按照视频中的内容进行了操作，但是只将语言从JS更改为C＃

Answer 1

将其分配为null：

public Camera mainCam = null;

但是您很可能会错过在Unity3D编辑器中将相机对象附加到它的功能。检查您的检查器，并确保使用此脚本（GameSetup.cs）的任何对象均已将相机对象分配给其公共变量。

应该看起来像这样。您必须将相机对象拖放到Gameobject。

Unity中未分配的变量

1 个答案: