# 5-3 箭頭與角色衝突判定
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ArrowController : MonoBehaviour
{
    // Start is called before the first frame update
    GameObject player;
    void Start()
    {
        this.player = GameObject.Find("player"); //聯結到player物件
    }

    // Update is called once per frame
    void Update()
    {
    // 每個影格等速往下移動
    transform.Translate(0, -0.1f, 0);

    // 當箭頭超出遊戲畫面時就捨棄物件
    if (transform.position.y < -5.0f) {
        Destroy(gameObject);
    }    

    // 衝突判定
    Vector2 p1 = transform.position;        //箭頭的圓心座標
    Vector2 p2 = this.player.transform.position; //遊戲角色的圓心座標
    
    Vector2 dir = p1 - p2;
    float d = dir.magnitude;    // 距離長度
    
    float r1 = 0.5f;    //箭頭角色的圓半徑 
    float r2 = 1.0f;    //遊戲角色的圓半徑

    if (d < r1 + r2) {
        //發生衝突時就捨棄箭頭
        Destroy(gameObject);
    }
    }
}