Unity如何实现3D贪吃蛇

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


public class GameManager : MonoBehaviour
{
 List bodyList = new List();//身体位置的列表
 private float speed = 2f;//移动速度
 public GameObject bodyObj;//用来生成的身体对象
 List bodyCreatePostion = new List();//身体部分的transfrom 列表
 private float TransOffset=1f;//位置间隔
 private List mapAddress=new List();//前进目标在地图上的位置，
 public Transform firstBody;//第一个身体部件的transfrom
 const int row = 100;//地图宽
 const int col = 100;//地图高
 int step=1;//步伐
 int x=0, z=0;//记录x和z轴的移动量

 // Start is called before the first frame update
 public Vector3[,] map = new Vector3[row, col];//地图
 // Start is called before the first frame update
 void Start()
 {
  
  for (int i = 0; i < row; i++)//生成地图
  {
   for (int j = 0; j < col; j++)
   {
    map[i, j] = new Vector3(i, 1.5f, j);
   }
  }
  transform.position =map[0,0];将当前位置设为原点
  mapAddress.Add(new Vector2(1,0));//增加第一个目标
  bodyList.Add(transform);//刷新第一个头和一个身体的transform
  bodyList.Add(firstBody);
  mapAddress.Add(new Vector2(0,0));
 }

 // Update is called once per frame
 void Update()
 {
  for (int i = 0; i < row - 1; i++)
  {
   for (int j = 0; j < col - 1; j++)//绘制地图格子
   {
    Debug.DrawLine(map[i, j], map[i + 1, j], Color.red);
    Debug.DrawLine(map[i, j], map[i, j + 1], Color.red);
   }
  }
  if (Input.anyKeyDown)//有任何键按下
  {
   if (Input.GetKeyDown(KeyCode.W) && z != -step)//上
   {
    z = step;
    x = 0;


   }
   if (Input.GetKeyDown(KeyCode.S) && z != step)//下
   {
    z = -step;
    x = 0;
    
   
   }
   if (Input.GetKeyDown(KeyCode.A) && x != step)//左
   {
    x = -step;
    z = 0;

   
   }
   if (Input.GetKeyDown(KeyCode.D) && x != -step)//右
   {
    x = step;
    z = 0;
   
    
   }
   

  }
  Move();


 }
 private void Move()//移动
 {


  if (Vector3.Distance(bodyList[0].position, map[(int)mapAddress[0].x + x, (int)mapAddress[0].y + z]) < 0.7f)//当前坐标和目标位置的距离小于0.5f
  {
   
   for (int i = mapAddress.Count - 1; i > 0; i--)//刷新后一个的目标为前一个的目标
   {
    mapAddress[i] = mapAddress[i-1];
   }
   
   mapAddress[0] = new Vector2(mapAddress[0].x + x, mapAddress[0].y + z);//刷新第一个目标的位置

  }
  else
  {
   for (int i = bodyList.Count - 1; i > 0; i--)//移动
   {
    bodyList[i].position = Vector3.MoveTowards(bodyList[i].position,
              map[(int)mapAddress[i - 1].x, (int)mapAddress[i - 1].y], Time.deltaTime * speed);

   }
   bodyList[0].position = Vector3.MoveTowards(transform.position,
             map[(int)mapAddress[0].x + x, (int)mapAddress[0].y + z], Time.deltaTime * speed);
  }
 }

 private void OnCollisionEnter(Collision collision)//碰撞到了食物就增加身体长度
 {

  if (collision.collider.tag == "Food")
  {
   
   Destroy(collision.collider.gameObject);
   GameObject tmpGameObject=new GameObject();
   Vector2 tmpVec = new Vector2();
   
   tmpGameObject = Instantiate(bodyObj, map[(int)mapAddress[mapAddress.Count - 1].x+x, (int)mapAddress[mapAddress.Count - 1].y +z], Quaternion.identity);//生成body物体
   tmpVec = new Vector2(mapAddress[mapAddress.Count - 1].x+x, mapAddress[mapAddress.Count - 1].y +z);
   //增加身体的transform和目标向量
   bodyList.Add(tmpGameObject.transform);
   mapAddress.Add(tmpVec);
  }
  
 }
}