The Mysterious Volume UI

using UnityEngine;

using System.Collections;

public class OVRVolumeControl : MonoBehaviour

{

    private const float         showPopupTime = 3;

    private const float            popupOffsetY = 64.0f / 500.0f;

    private const float            popupDepth = 1.8f;

    private const int             maxVolume = 15;

    private const int             numVolumeImages = maxVolume + 1;

    private Transform            myTransform = null;

    private float LastVolumeInput;

    private float TempVolumeInput;

    private float TimeToCheck = 0.0f;

    void Start()

    {

        DontDestroyOnLoad( gameObject );

        myTransform = transform;

        GetComponent<Renderer>().enabled = false;

        LastVolumeInput = OVRManager.volumeLevel;

    }

    void Update()

    {

        UpdatePosition(Camera.main.transform);

    }

    /// <summary>

    /// Updates the position of the volume popup. 

    /// </summary>

    public void UpdatePosition(Transform cameraTransform)

    {

        // OVRManager.volumeLevel returns a negative value in GearVR/Unity until the button is hit at least once.

        float check = OVRManager.volumeLevel;

        if ((check < 0f) || (check == LastVolumeInput))  // we haven't gotten a volume button check yet.

        {

            TimeToCheck = 0f;

        }

        else

        {

            LastVolumeInput = -10; // there was a change, let this play out.

            if (TempVolumeInput != check)

                TimeToCheck = 0.0f;

            TempVolumeInput = check;

            // Volume has changed...

            TimeToCheck += Time.deltaTime;

            if ((TimeToCheck < showPopupTime)) // for the next three seconds ....

            {

                GetComponent<Renderer>().enabled = true;

                GetComponent<Renderer>().material.mainTextureOffset = new Vector2(0.0f, (float)(maxVolume - (OVRManager.volumeLevel*maxVolume) ) / (float)numVolumeImages);

                if (myTransform != null && cameraTransform != null)

                {

                    // place in front of camera

                    myTransform.rotation = cameraTransform.rotation;

                    myTransform.position = cameraTransform.position + (myTransform.forward * popupDepth) + (myTransform.up * popupOffsetY);

                }

            }

            else

            {

                // 3 seconds have passed...

                TimeToCheck = 0.0f;

                LastVolumeInput = check;

                GetComponent<Renderer>().enabled = false;

            }

        }

    }

}

if (volumeController != null)
{
  if (volumeControllerTransform == null)
  {
    if (gameObject.GetComponent<OVRCameraRig>() != null)
    {
      volumeControllerTransform = gameObject.GetComponent<OVRCameraRig>().centerEyeAnchor;
    }
  }
  volumeController.UpdatePosition(volumeControllerTransform);
}

        if (volumeController != null)
        {
            if (volumeControllerTransform == null)
            {
                volumeControllerTransform = gameObject.transform;
            }
            volumeController.UpdatePosition(volumeControllerTransform);
        }  

And now it's working.