unity_效果实现_移动按钮UI界面的交互实现(单位向量)

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;

public class MyJoystic : MonoBehaviour, IDragHandler, IEndDragHandler
{
Vector3 startPos;
void Start()
{
startPos = transform.position;
}
public void OnDrag(PointerEventData eventData)
{
if (Vector3.Distance(startPos, Input.mousePosition) < 88)
{
transform.position = Input.mousePosition;
}
else
{
Vector3 to = Input.mousePosition - startPos;
transform.position = startPos + to.normalized * 88;
}
}
public void OnEndDrag(PointerEventData eventData)
{
transform.localPosition = Vector3.zero;
}
}