3Dball joystick controller

using System.Collections;
using System.Collections.Generic;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using UnityEngine;

public class Joystick : MonoBehaviour, IDragHandler, IPointerUpHandler, IPointerDownHandler
{
    public Image BGimg, joystickIMG;

    public Vector3 direction;
    // Use this for initialization
    void Start () {
        BGimg = GetComponent<Image>();
        joystickIMG = transform.GetChild(0).GetComponentInChildren<Image>();
        direction = Vector3.zero;
    }

    public void OnDrag(PointerEventData ped)
    {
        Vector2 pos = Vector2.zero;
        if(RectTransformUtility.ScreenPointToLocalPointInRectangle(
            BGimg.rectTransform, ped.position,
            ped.pressEventCamera, out pos))
        {
            pos.x = (pos.x / BGimg.rectTransform.sizeDelta.x);
            pos.y = (pos.y / BGimg.rectTransform.sizeDelta.y);

            float x = (BGimg.rectTransform.pivot.x == 1) ? pos.x * 2 + 1 : pos.x * 2 - 1;
            float y = (BGimg.rectTransform.pivot.y == 1) ? pos.y * 2 + 1 : pos.y * 2 - 1;

            direction = new Vector3(x, 0, y);
            direction = (direction.magnitude > 1) ? direction.normalized : direction;

            joystickIMG.rectTransform.anchoredPosition =
                new Vector2(direction.x * (BGimg.rectTransform.sizeDelta.x / 3),
                direction.z * (BGimg.rectTransform.sizeDelta.y / 3));


            Debug.Log(direction);
        }

    }

    public void OnPointerDown(PointerEventData ped)
    {
        OnDrag(ped);
    }

    public void OnPointerUp(PointerEventData ped)
    {
        direction = Vector3.zero;
        joystickIMG.rectTransform.anchoredPosition = Vector3.zero;
    }
}