Unity实现简单虚拟摇杆

public class YaoGanCtrl : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
 public RectTransform diPan;
 public RectTransform anNiu;
 public Vector2 direction;
 Vector2 startPos;
 public float moveRange;

 public void OnBeginDrag(PointerEventData eventData)
 {
 //获取中心按钮的初始位置
 startPos = anNiu.position;
 }

 public void OnDrag(PointerEventData eventData)
 {
 //计算摇杆方向
 Vector2 newDir = eventData.position - startPos;
 //计算活动范围的半径
 float r = Mathf.Clamp(newDir.magnitude, -moveRange, moveRange);
 //获取摇杆的单位方向
 direction = newDir.normalized;
 //设置中心按钮位置
 anNiu.position = startPos + direction * r;
 }

 public void OnEndDrag(PointerEventData eventData)
 {
 //重置中心按钮位置
 anNiu.position = startPos;
 //重置单位方向
 direction = Vector2.zero;
 }

}