How can i use virtual joystick for control fps character controller?

Here is my virtual joystick controller script. Now how can i use this for control fps character controller movement both forward and side?

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

 public class JoyStickController : MonoBehaviour , IDragHandler, IPointerUpHandler ,IPointerDownHandler{

 private Image bgImg;
 private Image joyStickImg;
 public Vector3 InputDirection{ set; get; }
 // Use this for initialization
 void Start () {
 bgImg = GetComponent<Image> ();
 joyStickImg = transform.GetChild (0).GetComponent<Image> ();
 InputDirection = Vector3.zero;
 }
 public virtual 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;
     InputDirection = new Vector3 (x, 0, y);
     InputDirection = (InputDirection.magnitude > 1) ? InputDirection.normalized : InputDirection;
     joyStickImg.rectTransform.anchoredPosition = new Vector3 (InputDirection.x * (bgImg.rectTransform.sizeDelta.x / 3)
         , InputDirection.z * (bgImg.rectTransform.sizeDelta.y / 3));
     }
  }
   public virtual void OnPointerDown(PointerEventData ped){
  OnDrag (ped);
  }
  public virtual void OnPointerUp(PointerEventData ped){
 InputDirection = Vector3.zero;
 joyStickImg.rectTransform.anchoredPosition = Vector3.zero;
 Debug.Log("Unpress");
  }
  public float Horizontal()
  {
 if (InputDirection.x != 0)
     return InputDirection.x;        
 else
     return Input.GetAxis("Horizontal");
  }
  public float Vertical()
 {
 if (InputDirection.z != 0)
     return InputDirection.z;
 else
     return Input.GetAxis("Vertical");
  }
  }