using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
/// <summary>
/// 搖杆腳本【挂到可以設定的拖拽區域UI上】
/// </summary>
public class M_Touch : MonoBehaviour,IPointerDownHandler,IPointerUpHandler,IDragHandler {
public Transform TouchBack;//搖杆背景圈
public Transform Touch;//搖杆圖示
//搖杆最大位移【應根據螢幕變化比例變化】
private const float MaxLen = 100;
public Vector2 starVec = Vector2.zero;
void Start()
{
starVec = Touch.position;//記錄搖杆本來螢幕的位置
}
public void OnPointerDown(PointerEventData eventData)
{
DoMove(eventData);
}
public void OnPointerUp(PointerEventData eventData)
{
Touch.localPosition = Vector2.zero;//擡起手指回最初點
}
public void OnDrag(PointerEventData eventData)
{
DoMove(eventData);
}
private void DoMove(PointerEventData eventData)
{
Vector2 dir = eventData.position - starVec;
float len = dir.magnitude;
if (len > MaxLen)
{
//限定向量長度
Vector2 clampDir = Vector2.ClampMagnitude(dir, MaxLen);
Touch.position = starVec + clampDir;
}
else
{
Touch.position = eventData.position;
}
}
}