Got them, thank you.

I would have one more request: if you have any chance to use Unity 4.1.5, could you try to see if you can reproduce the same issue on 4.1.5 (using GL ES 2.0) ?

(Just creating an empty project with an ARCamera, starting with the camera enabled, and then use the script to Enable/Disable QCARBehaviour, which I previously provided in previous post )?

That would also help understand if the issue is related to the 4.2 rendering piepline, or if it is a more general issue.

As a side note:

if the goal is to skip the rendering of the camera video background,

rather than disabling the ARCamera or the QCARBehaviour you may try these options:

 //hide background video

Yes, thanks, if you can provide a GPU trace that might help understanding what goes wrong.

Nexus 4 has displayed this in more than one project now. The Galaxy Note II has also been seen to have this error. Devices like the Nexus 7 do not. I can get you a trace from the GPU if you'd like.

Good to hear that you found a workaround by using OpenGL ES 1.1.

However, just wondering if this issue is only observed on the Nexus 4; have you tried on other devices (using OpenGL ES 2.0) and have you observed the same ?

Also, in the method which causes the camera to work, pausing the app and resuming causes the app to be black, then crash.

EDIT: Changing the GL ES version to 1.x seems to fix the crash, however that's a hit for flexibility. This has fixed all of my issues.

Uninstalled / restarted device, and went back to my ARCamera prefab, which shouldn't be any different from Vuforia's bundled. Works. But I'm still probably not allowed to start the camera later. My issue remains that the camera has to be rendering and enabled in all ways on start before disabling it to avoid a GL error.

Sorry for the run around. Thank you.

Wally

EDIT: Confirmed still an issue. Log on Nexus 4 Follows:

Process:

1- Load Scene

2- Press Button (Instantiates ARCamera prefab which worked previously from start).

EDIT EDIT: Adding your Monobehaviour to the setup which previously worked caused the camera feed to not display. Can provide logs if desired, don't want to spam you too much!

Also, Nexus 4 does not crash, however it does not get the camera. The interesting part of the log is as follows:

Thanks for the reply, Alessandro. I've tried just enabling/disabling QCARBehaviour before, but gave it a second go. This script works fine on an iPad Mini on iOS 7. On both the Nexus 4 and Galaxy Note II, however, the program takes forever to load, does not display the camera, and in the case of the Note II, crashes. Uninstalled old build, fresh build loaded quicker, but gave same results. Odd. Previously I could get the camera to work, so long as it started enabled. There is a second object in the scene, but it is disabled.

Crash log on the Galaxy Note II:

Hi wallyyoung,

could you test using this script (just create a new project with an empty scene and attach an ARCamera, then attach this script to the ARCamera):

/*==============================================================================
Copyright (c) 2013 QUALCOMM Austria Research Center GmbH.
All Rights Reserved.
Confidential and Proprietary - QUALCOMM Austria Research Center GmbH.
==============================================================================*/

using UnityEngine;
using System.Collections;

// Attach this to the ARCamera
public class EnableDisableTracker : MonoBehaviour
{
 private QCARBehaviour mQCAR = null;
 
 void Start() {
  mQCAR = (QCARBehaviour)UnityEngine.Object.FindObjectOfType(typeof(QCARBehaviour));
 }
 
    void OnGUI ()
    {
  int w = Screen.width;
  int h = Screen.height;
  
        if (GUI.Button(new Rect(w/2 - 200, h/2, 180, 50), "Disable Tracker"))
        {
            mQCAR.enabled = false;//this will cause camera and tracker to start
        }

        if (GUI.Button(new Rect(w/2 + 20, h/2, 180, 50), "Enable Tracker"))
        {
            mQCAR.enabled = true;// this will cause camera and tracker to stop
        }
  
  string logMsg = mQCAR.enabled ? "Tracker and Camera ENABLED" : "Tracker and Camera DISABLED";
  GUI.skin.box.fontSize = 18;
  GUI.Box(new Rect(w/2 - 200, h/2 + 100, 350, 50), logMsg);
    }
}

This is a script we normally use for testing enabling/disabling of QCARBehaviour.

Also, is this occurring in PlayMode or on a specific device ?

Thanks, David.

Starting the app with the object in scene, but QCARBehaviour disabled, then enabling it, causes a crash.

Starting the app with the object in scene, with QCARBehaviour enabled, but then disabling it off of Start, and later reenabling it, causes a crash.

Thank you!

Wally

Thanks for the thorough report. Let us look into this. In the interim, have you tried disabling the QCARBehaviour on the ARCamera to achieve what you're attempting? That will shut down the tracker and also background rendering.

I'm using 4.2.1f4. Only one scene, just instantiating a prefab with the camera, or enabling the camera, or changing RenderVideoBackground.

Thank you!

Wally

Which Unity version are you using, and is this occuring in an initial Vuforia scene or when navigating into a Vuforia scene?

There is a known issue w/ the current Unity extension version when loading the ARCamera from another scene. The work-around is to implement the ARCamera in the initial load scene and apply the Keep Alive behaviour described here - https://developer.vuforia.com/resources/dev-guide/special-options-unity in Keeping Vuforia objects alive across multiple Unity scenes.