抛光简单蛇游戏

Question

在本教程之后，我一直在联合(C#)创建一个简单的蛇游戏，我发现：

https://www.youtube.com/watch?v=U8gUnpeaMbQ&t=1s&ab_channel=Zigurous

我发现这是一个非常好的教程，到最后我有了一个完美的蛇游戏，然而，我想更进一步，使运动更愉快，添加一个尾巴，游戏，等等。

现在我的问题是，如果玩家连续按两个可以接受的方向，试图获取一些食物，蛇的头就会跳过食物，完全错过了。

发生这种情况的原因是以下代码：

private void Update() //Gets Key Inputs and execute Commands
{   
    if (Input.GetKeyDown(KeyCode.UpArrow) )
    {
        while(tempPosition == _segments[0].position)
        {
            for (int i = _segments.Count - 1; i > 0; i--)
            {
                _segments[i].position = _segments[i - 1].position;
            }
            this.transform.position = new Vector3(
                Mathf.Round(this.transform.position.x + _direction.x),
                Mathf.Round(this.transform.position.y + _direction.y),
                0.0f
                );
        }
        if(_direction != Vector2.down)
        {
            _direction = Vector2.up;
            tempPosition = _segments[0].position;
        }
        
    }
    else if (Input.GetKeyDown(KeyCode.LeftArrow) )
    {
        while (tempPosition == _segments[0].position)
        {
            for (int i = _segments.Count - 1; i > 0; i--)
            {
                _segments[i].position = _segments[i - 1].position;
            }
            this.transform.position = new Vector3(
                Mathf.Round(this.transform.position.x + _direction.x),
                Mathf.Round(this.transform.position.y + _direction.y),
                0.0f
                );
        }
        if (_direction != Vector2.right)
        {
            _direction = Vector2.left;
            tempPosition = _segments[0].position;
        }
    }
    else if (Input.GetKeyDown(KeyCode.RightArrow) )
    {
        while (tempPosition == _segments[0].position)
        {
            for (int i = _segments.Count - 1; i > 0; i--)
            {
                _segments[i].position = _segments[i - 1].position;
            }
            this.transform.position = new Vector3(
                Mathf.Round(this.transform.position.x + _direction.x),
                Mathf.Round(this.transform.position.y + _direction.y),
                0.0f
                );
        }
        if (_direction != Vector2.left)
        {
            _direction = Vector2.right;
            tempPosition = _segments[0].position;
        }
    }
    else if (Input.GetKeyDown(KeyCode.DownArrow) )
    {            
        while (tempPosition == _segments[0].position)
        {
            for(int i = _segments.Count -1; i>0; i--)
            {
                _segments[i].position = _segments[i - 1].position;
            }
            this.transform.position = new Vector3(
                Mathf.Round(this.transform.position.x + _direction.x),
                Mathf.Round(this.transform.position.y + _direction.y),
                0.0f
                );
        }
        if (_direction != Vector2.up)
        {
            _direction = Vector2.down;
            tempPosition = _segments[0].position;
        }
    }

正如你所看到的，按下一个键会立刻移动蛇的头，导致问题的发生。

然而，如果没有这样的编码，快速连续按下2个键就会使蛇与自身发生碰撞(假设蛇正在向右移动，如果向上和左侧被快速按压，蛇将开始向左移动，然后才能向上移动，与其身体发生碰撞)。

以下是完整的代码：

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

public class Snake : MonoBehaviour
{
private Vector2 _direction = Vector2.right;
public List<Transform> _segments = new List<Transform>();
public Transform segmentPrefab;
public Transform tail;
public int initialSize = 4;
public int score = 0;
private Vector3 tempPosition;
public GameObject food;
public Text gameOver;
private void Start()
{
    ResetState();
}
private void Update() //Gets Key Inputs and execute Commands
{   
    if (Input.GetKeyDown(KeyCode.UpArrow) )
    {
        while(tempPosition == _segments[0].position)
        {
            for (int i = _segments.Count - 1; i > 0; i--)
            {
                _segments[i].position = _segments[i - 1].position;
            }
            this.transform.position = new Vector3(
                Mathf.Round(this.transform.position.x + _direction.x),
                Mathf.Round(this.transform.position.y + _direction.y),
                0.0f
                );
        }
        if(_direction != Vector2.down)
        {
            _direction = Vector2.up;
            tempPosition = _segments[0].position;
        }
        
    }
    else if (Input.GetKeyDown(KeyCode.LeftArrow) )
    {
        while (tempPosition == _segments[0].position)
        {
            for (int i = _segments.Count - 1; i > 0; i--)
            {
                _segments[i].position = _segments[i - 1].position;
            }
            this.transform.position = new Vector3(
                Mathf.Round(this.transform.position.x + _direction.x),
                Mathf.Round(this.transform.position.y + _direction.y),
                0.0f
                );
        }
        if (_direction != Vector2.right)
        {
            _direction = Vector2.left;
            tempPosition = _segments[0].position;
        }
    }
    else if (Input.GetKeyDown(KeyCode.RightArrow) )
    {
        while (tempPosition == _segments[0].position)
        {
            for (int i = _segments.Count - 1; i > 0; i--)
            {
                _segments[i].position = _segments[i - 1].position;
            }
            this.transform.position = new Vector3(
                Mathf.Round(this.transform.position.x + _direction.x),
                Mathf.Round(this.transform.position.y + _direction.y),
                0.0f
                );
        }
        if (_direction != Vector2.left)
        {
            _direction = Vector2.right;
            tempPosition = _segments[0].position;
        }
    }
    else if (Input.GetKeyDown(KeyCode.DownArrow) )
    {            
        while (tempPosition == _segments[0].position)
        {
            for(int i = _segments.Count -1; i>0; i--)
            {
                _segments[i].position = _segments[i - 1].position;
            }
            this.transform.position = new Vector3(
                Mathf.Round(this.transform.position.x + _direction.x),
                Mathf.Round(this.transform.position.y + _direction.y),
                0.0f
                );
        }
        if (_direction != Vector2.up)
        {
            _direction = Vector2.down;
            tempPosition = _segments[0].position;
        }
    }
    if(Input.GetKeyDown(KeyCode.R))
    {
        ResetState();
    }
}
private void FixedUpdate() //Handles moviment
{
    if (gameOver.gameObject.activeSelf == false)
    {            
        for (int i = _segments.Count - 1; i > 0; i--)
        {
            _segments[i].position = _segments[i - 1].position;
        }
        this.transform.position = new Vector3(
            Mathf.Round(this.transform.position.x + _direction.x),
            Mathf.Round(this.transform.position.y + _direction.y),
            0.0f
            );
    }
}
/*Instantiates a new segment, sets it's position to tail position,
  destroys tail from list and adds new segment in it's place, adds new tail at end*/
private void Grow() 
{
    Transform segment = Instantiate(this.segmentPrefab);
    segment.position = _segments[_segments.Count - 1].position;
    Destroy(_segments[_segments.Count - 1].gameObject);
    _segments.Remove(_segments[_segments.Count - 1]);
    _segments.Add(segment);
    Transform segmenttail = Instantiate(this.tail);

    segmenttail.position = _segments[_segments.Count - 1].position;

    _segments.Add(segmenttail);
}
private void ResetState()
{
    gameOver.gameObject.SetActive(false);
    tempPosition.x = 1000;
    score = 0;
    for (int i = 1; i < _segments.Count; i++)
    {
        Destroy(_segments[i].gameObject);
    }
    _segments.Clear();
    _segments.Add(this.transform);
    for (int i = 1; i < initialSize; i++)
    {
        _segments.Add(Instantiate(this.segmentPrefab));
    }
    _segments.Add(Instantiate(this.tail));
    this.transform.position = Vector3.zero;
    this.GetComponent<SpriteRenderer>().enabled = (true);
    food.GetComponent<Food>().RandomizePosition();
}
private void OnTriggerEnter2D(Collider2D other)
{
    if (other.tag == "Food")
    {
        Grow();
        score++;
    }
    else if(other.tag == "Obstacle")
    {
        for (int i = 1; i < _segments.Count; i++)
        {
            Destroy(_segments[i].gameObject);
        }
        this.GetComponent<SpriteRenderer>().enabled=(false);
        _segments.Clear();
        food.gameObject.SetActive(false);
        gameOver.gameObject.SetActive(true);
    }

}

}

tl;dr:在一个简单的蛇游戏中，当两个方向被快速地按下时，我如何确保蛇在转向第二个方向之前，在没有错误的情况下，向第一个方向移动。

，谢谢！

Answer 1

制作一个红色立方体，控制蛇的运动方向，以及遇到食物和吃东西的功能。在Update()中，WSAD和方向键控制蛇头的移动方向。当蛇头向上移动时，它不能向下移动，当蛇向左移动时，它就不能向右移动。

         void Update () {
         if (Input.GetKey(KeyCode.W)||Input.GetKey("up")&&direction!= 
Vector2.down)
    {
        direction = Vector2.up;
    }
    if (Input.GetKey(KeyCode.S) || Input.GetKey("down") && direction != Vector2.up)
    {
        direction = Vector2.down;
    }
    if (Input.GetKey(KeyCode.A) || Input.GetKey("left") && direction != Vector2.right)
    {
        direction = Vector2.left;
    }
    if (Input.GetKey(KeyCode.D) || Input.GetKey("right") && direction != Vector2.left)
    {
        direction = Vector2.right;
    }

}

当蛇与食物相撞后，它的身体就会长出一段。当遇到食物时，它会首先破坏食物，然后增加自己身体的长度。此时，设置的碰撞位标志将变为真，身体长度将增加。然而，当它撞到自己，当它撞到一堵墙时，它就会死掉，此时，它将在一开始就被导入到场景中。

  void OnTriggerEnter(Collider other)
  {
    if (other.gameObject.CompareTag("Food"))
    {
        //Debug.Log("hit it!");
        Destroy(other.gameObject);
        flag = true;

    }
    else
    {
        //SceneManager.LoadScene(0)
        Application.LoadLevel(1);
    }
}

身体每次生长的算法就是吃蛇的难度。Internet上的许多算法都是通过使用链表来实现的。链表的节点表示蛇的增加或减少非常方便。移动时，只需添加一个头节点并删除它。尾节点就足够了，要吃东西，只需要添加一个头节点。这个算法是绝对巧妙的，但由于互联网上有太多，下面是另一个由链接列表实现的吃蛇算法。蛇的头一动也不动，最后的身体移到前面，然后慢慢地向后移动。下面的蓝色方格(身体部分的设置)一步一步地移动，你可以看到这种效果。蛇的身体部分的代码张贴在下面。如果食物被吃了，旗子就是真的。这是为了插入一个预制立方体到蛇的身体，蛇的身体将增长更长。当没有食物的时候，它会在此时观察身体的数量。当数字大于0时，最后一个将放置在前面，循环将一直持续到结束。

  void Move()
  {
    Vector3 VPosition = transform.position;
    transform.Translate(direction);
    if (flag)
    {
        GameObject bodyPrefab = (GameObject)Instantiate(gameObjecgtBody, VPosition, Quaternion.identity);
        Body.Insert(0, bodyPrefab.transform);
        flag = false;
    }
    else if (Body.Count > 0)
    {
        Body.Last().position = VPosition;
        Body.Insert(0, Body.Last());
        Body.RemoveAt(Body.Count - 1);
    }
}

食物的出现是一个随机的过程。此时，食物出现在一个随机的位置。InvokeRepeating(" ShowFood "，1，4)；意味着ShowFood()函数将在4秒内被调用，此时它将随机出现在ShowFood中。食物。下面是ShowFood()函数的代码

void ShowFood()
 {
    int x = Random.Range(-30, 30);
    int y = Random.Range(-22, 22);
    Instantiate(SSFood, new Vector2(x,y), Quaternion.identity);
    
  }

特别注意的是，当制作蛇头和蛇身时，如果将碰撞体的体积设置为单元1，则蛇体的侧面也会撞到食物，触发对撞机。所以把对撞机的体积设置为0.8，这略小于1，我也从互联网上找到了信息，希望它能对你有所帮助，这个链接是源代码https://github.com/xiaogeformax/Snake/tree/master/Snake5.2