JoystickUnity5.1

using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;

public enum JoystickType {
    Round,
    Square
}

public struct Bounds {
    public Vector2 min;
    public Vector2 max;
}

public class Joystick : MonoBehaviour, IDragHandler, IEndDragHandler {

    public Vector2 output {
        get {
            return p_output;
        }
    }

    public JoystickType joystickType = JoystickType.Round;
    public Vector2 deadZone = Vector2.zero;
    public float maxDistance = 50f;
    public bool smooth = true;

    new private RectTransform transform;
    private Bounds bounds;
    private Vector2 defaultPosition;
    private Vector2 position;
    private Vector2 p_output;

    private void Start() {
        transform = GetComponent<RectTransform>();
        defaultPosition = transform.position;

        bounds.max = (Vector2)transform.position + Vector2.one * maxDistance;
        bounds.min = (Vector2)transform.position - Vector2.one * maxDistance;
    }

    public void OnDrag(PointerEventData data) {
        position = transform.position;
        position += data.delta;

        switch(joystickType) {
            case JoystickType.Round:
            position = Vector2.ClampMagnitude(position - defaultPosition, maxDistance) + defaultPosition;
            break;
            case JoystickType.Square:
            position.x = Mathf.Clamp(position.x, bounds.min.x, bounds.max.x);
            position.y = Mathf.Clamp(position.y, bounds.min.y, bounds.max.y);
            break;
        }

        p_output = position - defaultPosition;
        p_output /= maxDistance;

        if(Mathf.Abs(p_output.x) < deadZone.x)
            p_output.x = 0f;
        if(Mathf.Abs(p_output.y) < deadZone.y)
            p_output.y = 0f;

        if(smooth) {
            p_output.x *= Mathf.Abs(p_output.x);
            p_output.y *= Mathf.Abs(p_output.y);
        }

        transform.position = position;
    }

    public void OnEndDrag(PointerEventData data) {
        transform.position = defaultPosition;
        p_output = Vector2.zero;
    }
}