public void setupGui(Camera leftCam, Camera rightCam, ViewPort left, ViewPort right) {

        if (environment != null){
            if( environment.hasTraditionalGUIOverlay() ) {
                camLeft = leftCam;
                camRight = rightCam;
                Spatial guiScene = getGuiQuad(camLeft);
                left.attachScene(guiScene);
                if( right != null ) right.attachScene(guiScene);
                setPositioningMode(posMode);
            }
        } else {
            throw new IllegalStateException("VR GUI manager is not attached to any environment.");
        }
    }
Set up the GUI.
@param leftCam the left-eye camera.
@param rightCam the right-eye camera.
@param left the left-eye viewport.
@param right the right-eye viewport.
jme3-vr/src/main/java/com/jme3/util/VRGuiManager.java