using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;//導(dǎo)入命名空間

public class JoyStick : MonoBehaviour,IPointerDownHandler,IPointerUpHandler {//實(shí)現(xiàn)接口

 private bool isTouched = false;//標(biāo)志位，用于標(biāo)示值是否拖拽按鈕
 private static float h = 0;
 private static float v = 0;//這兩者用于表示水平（豎直）方向按鈕移動的值，相當(dāng)于通過Input.GetAxis("Horizontal");Input.GetAxis("Vertical");
 [SerializeField] private Vector2 joystickPivot;//按鈕中心位置在世界坐標(biāo)中的值
 [SerializeField] private float radius;//按鈕的半徑（決定了按鈕的活動范圍）

 // Update is called once per frame
 void Update () {
 if (isTouched)
 {
  Vector2 mouPos = Input.mousePosition;
  mouPos -= joystickPivot;//將鼠標(biāo)位置轉(zhuǎn)換為本地坐標(biāo)
  if (Vector2.Distance(mouPos,Vector2.zero)>=radius)//如果鼠標(biāo)移動超出范圍，將圖片放到邊緣
  {
  mouPos = mouPos.normalized*radius;
  }
  transform.localPosition = mouPos;
  h = mouPos.x/radius;
  v = mouPos.y/radius;

 }
 }

 public void OnPointerDown(PointerEventData eventData)
 {
 isTouched = true;
 }

 public void OnPointerUp(PointerEventData eventData)
 {
 isTouched = false;
 h = 0;
 v = 0;//不拖拽時二者為0
 transform.localPosition = Vector3.zero;//讓按鈕返回中心魏智
 }
}