public float Speedrotate;
public float AttackDamage;
   
    private Vector2 speedVelocity;
    private float Speedtemprotate;//中間變量記錄最大旋轉(zhuǎn)速度
    
    bool first = true;//此bool值代表是否是第一階段：即丟出去的飛行階段
    void Start()
    {
        speedVelocity = gameObject.GetComponent<Rigidbody2D>().velocity;
        Speedtemprotate = Speedrotate;
    }
    private void FixedUpdate()
    {
     transform.Rotate(0, 0, Speedrotate);//根據(jù)旋轉(zhuǎn)速度來自轉(zhuǎn)
     if(Speedrotate > 0 && first)//旋轉(zhuǎn)速度和飛行隨時間減小，直到為0就停止運動
     {
         gameObject.GetComponent<Rigidbody2D>().velocity -= speedVelocity * 0.02f;
            Speedrotate -= (Speedtemprotate * 0.02f);
     }
     else if(Speedrotate<0&&first)//第一階段結(jié)束開始過渡第二階段
     {
      speedVelocity = gameObject.GetComponent<Rigidbody2D>().velocity =      (GameObject.Find("Player").transform.position - transform.position).normalized;
      //獲得新的速度（因為玩家可能會移動到任何位置，所以不能只是單純往回飛）
             first = false;//第二階段開始
     }
     else if(!first)//第二階段回旋鏢一直往玩家方向飛行
     {
         Speedrotate += (Speedtemprotate * 0.02f);//這個0.02f速度可以調(diào)快一點看個人喜愛
            float x = GameObject.Find("Player").transform.position.x;
            float y = GameObject.Find("Player").transform.position.y;
            Vector2 dir = new Vector2(x - transform.position.x, y - transform.position.y).normalized * Time.deltaTime;
            transform.Translate(dir * Time.fixedDeltaTime * 500,Space.World);
     }
    }
     private void OnTriggerEnter2D(Collider2D collision)
     {
      if (collision.tag == "Enemy" && first)
      {
          first = false;
            Speedrotate = 0;//強行結(jié)束first階段
            
            other.GetComponent<Enemy>.TakeDamage(damage);//對敵人造成傷害
      }
      
}

private void Update()
{
 if (!isCanweapon) TimeweaponBack += Time.deltaTime;//獲取回旋鏢返回時間
        TimeweaponShoot += Time.deltaTime;//設(shè)置回旋鏢冷卻
 //發(fā)射回旋鏢
 if(TimeweaponShoot>=AttackSpeed&&Input.GetAxis("Fire2")==1&&isCanweapon)
 {
     TimeweaponBack = 0;
            isCanweapon = false;
            Vector3 worldPos = Camera.main.ScreenToWorldPoint(Input.mousePosition);//獲取當(dāng)前屏幕的點
            Vector3 dir = worldPos - transform.position;//獲取玩家與屏幕的方向
            dir.z = 0;//2D游戲不需要z軸
            GameObject go = Instantiate(weapon, transform.position+dir.normalized*0.2f, transform.rotation);
            go.GetComponent<Rigidbody2D>().velocity = dir.normalized*4;//給回旋鏢速度
        
 }
}
 private void OnTriggerEnter2D(Collider2D collision)
 {
  //撿返回的回旋鏢
        if(collision.tag=="weapon"&& TimeweaponBack > 0.03f)
        {
            isCanweapon = true;
            TimeweaponShoot = 0;
            Destroy(collision.gameObject);
        }
 }

void Start()
{
 rb2D=GetComponent<Rigidbody2D>();
 
 rb2D.velocity=transform.right*speed;//給回旋鏢初始速度
 
 startSpeed=rb2D.velocity;//記錄初始速度
 
 playerTransform=GameObject.FindGameObjectWithTag("Player").GetComponment<Transform>();//獲得玩家位置
 void Update()
{
 transform.Rotate(0,0,rotateSpeed);//自我旋轉(zhuǎn)
 
 float y=Mathf.Lerp(transform.position.y,playerTransform.position.y,0.1);//讓回旋鏢y軸和玩家在一起
 transform.position=new Vector3(transform.position.x,y,0.0f);
 
 rb2D.velocity-=startSpeed*Time.deltaTime;//使回旋鏢慢慢減速，到達0之后速度方向為之前的反方向飛回來
 
 if(Mathf.Abs(transform.position.x-playerTransform.position.x)<0.5f)
  {
    Destory(gameObject);//飛回玩家手里
  }
}

}
void OnTriggerEnter2D(Collider2D other)
{
 if(other.gameObject.CompareTag("Enemy"));
 {
  other.GetComponent<Enemy>.TakeDamage(damage);//對敵人造成傷害 
 }
}