Ketai camera in VR mode - crashes

Processing for Android
1

Hallo, i try to make ketai camera work in VR mode is it possible?
i have the following code from ketai and imported VR

/**
 * <p>Ketai Sensor Library for Android: http://ketai.org</p>
 *
 * <p>Ketai Camera Features:
 * <ul>
 * <li>Interface for built-in camera</li>
 * <li>Access camera flash</li>
 * </ul>
 * <p>Updated: 2017-09-01 Daniel Sauter/j.duran</p>
 */

import ketai.camera.*;
import processing.vr.*;
KetaiCamera cam;

void setup() {
  fullScreen(STEREO);
  //orientation(LANDSCAPE);

  imageMode(CENTER);

  cam = new KetaiCamera(this, 320, 240, 24);
  cam.start();
}

void draw() {

  if (cam != null && cam.isStarted())
    image(cam, width/2, height/2, cam.width, cam.height);
  else
  {
    background(128);
    //text("Camera is currently off.", width/2, height/2);
  }
  //drawUI();
}

void onCameraPreviewEvent()
{
  cam.read();
}

but after builded successfully when it tries to open in the phone it crashes with

FATAL EXCEPTION: main
Process: processing.test.cameragettingstarted2, PID: 14687
java.lang.ClassCastException: processing.android.PFragment cannot be cast to com.google.vr.sdk.base.GvrActivity
	at processing.vr.VRSurface.<init>(VRSurface.java:68)
	at processing.vr.VRGraphicsStereo.createSurface(VRGraphicsStereo.java:33)
	at processing.core.PApplet.initSurface(PApplet.java:538)
	at processing.android.PFragment.onCreateView(PFragment.java:149)
	at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2600)
	at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:881)
	at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1238)
	at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1303)
	at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439)
	at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2079)
	at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1869)
	at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1824)
	at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1727)
	at androidx.fragment.app.FragmentManagerImpl.dispatchStateChange(FragmentManagerImpl.java:2663)
	at androidx.fragment.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManagerImpl.java:2613)
	at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:246)
	at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:542)
	at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:210)
	at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1436)
	at android.app.Activity.performStart(Activity.java:8024)
	at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3456)
	at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:221)
	at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)
	at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)
	at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2067)
	at android.os.Handler.dispatchMessage(Handler.java:106)
	at android.os.Looper.loop(Looper.java:223)
	at android.app.ActivityThread.main(ActivityThread.java:7698)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:952)

is it possible to use the camera in VR mode?

2

seems placing a background(0); at the beggining of draw() fixed the issue