RadialSlider.cs

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

public class RadialSlider : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler, IPointerDownHandler, IPointerUpHandler { bool isPointerDown = false;

// Called when the pointer enters our GUI component.
// Start tracking the mouse
public void OnPointerEnter( PointerEventData eventData )
{
    StartCoroutine( "TrackPointer" );
}

// Called when the pointer exits our GUI component.
// Stop tracking the mouse
public void OnPointerExit( PointerEventData eventData )
{
    StopCoroutine( "TrackPointer" );
}

public void OnPointerDown( PointerEventData eventData )
{
    isPointerDown = true;
    //Debug.Log("mousedown");
}

public void OnPointerUp( PointerEventData eventData )
{
    isPointerDown = false;
    //Debug.Log("mousedown");
}

// mainloop
IEnumerator TrackPointer()
{
    var ray = GetComponentInParent<GraphicRaycaster>();
    var input = FindObjectOfType<StandaloneInputModule>();

    var text = GetComponentInChildren<Text>();

    if ( ray != null && input != null )
    {
        while ( Application.isPlaying )
        {

            // TODO: if mousebutton down
            if ( isPointerDown )
            {

                Vector2 localPos; // Mouse position
                RectTransformUtility.ScreenPointToLocalPointInRectangle( transform as RectTransform, Input.mousePosition, ray.eventCamera, out localPos );

                // local pos is the mouse position.
                float angle = ( Mathf.Atan2( -localPos.y, localPos.x ) * 180f / Mathf.PI + 180f ) / 360f;

                GetComponent<Image>().fillAmount = angle;

                GetComponent<Image>().color = Color.Lerp( Color.green, Color.red, angle );

                text.text = ( ( int )( angle * 360f ) ).ToString();

                //Debug.Log(localPos+" : "+angle);
            }

            yield return 0;
        }
    }
    else
        UnityEngine.Debug.LogWarning( "Could not find GraphicRaycaster and/or StandaloneInputModule" );
}

}