using system.collections;
using system.collections.generic;
using unityengine;

public class snackbody
{
  public snackbody front; //表示 前一段蛇身
  public transform self; //表示 当前蛇身
  vector3 oldpos; //当前蛇身的前一个位置

  public snackbody(snackbody tmpfront, transform tmpself)
  {
    front = tmpfront;
    self = tmpself;
    oldpos = tmpself.position;
  }

  //这一节蛇身已经向前移动了，更新oldpos
  public void reflash()
  {
    oldpos = this.self.position;
  }

  //跟着前面的蛇身
  public void followfront()
  {
    self.position = front.oldpos; //更新蛇身的位置
    front.reflash(); 
  }
  
  public virtual void moveforward(){}
  }

public class snackhead : snackbody
{
  //继承基类
  public snackhead(snackbody tmpfront,transform tmpself):base(tmpfront,tmpself) 
  {
  }
  public override void moveforward()
  {
    self.translate(-self.forward, space.world);
  }

  /// <summary>
  /// 向右移动
  /// </summary>
  public void turnright()
  {
    vector3 tmpangle = self.localeulerangles;
    tmpangle.y += 90;
    self.localeulerangles = tmpangle;
  }

  /// <summary>
  /// 向左移动
  /// </summary>
  public void turnleft()
  {
    vector3 tmpangle = self.localeulerangles;
    tmpangle.y -= 90;
    self.localeulerangles = tmpangle;
  }
}

using system.collections;
using system.collections.generic;
using unityengine;

public class snackcontroller : monobehaviour {

  list<snackbody> allbodys; //存储所有的蛇身

  public transform snackhead;
  public transform bodyone;
  public transform bodytwo;

  // use this for initialization
  void start () {

    allbodys = new list<snackbody>();

    snackhead tmphead = new snackhead(null, snackhead);
    allbodys.add(tmphead);

    snackbody tmponebody = new snackbody(tmphead, bodyone);
    allbodys.add(tmponebody);

    snackbody tmptwobody = new snackbody(tmponebody, bodytwo);
    allbodys.add(tmptwobody);

    startcoroutine(movefront());
  }

  ienumerator movefront()
  {
    while(true) //用一个死循环来让蛇一直移动
    {
      allbodys[0].moveforward();

      yield return new waitforseconds(0.5f);

      for(int i=1;i<allbodys.count; i++)
      {
        allbodys[i].followfront();
        yield return new waitforseconds(0.2f);
      }
    }
  }
 
 // update is called once per frame
 void update () {
 
    if(input.getkeydown(keycode.a))
    {
      ((snackhead)allbodys[0]).turnleft();
    }

    if (input.getkeydown(keycode.d))
    {
      ((snackhead)allbodys[0]).turnright();
    }
  }
}