createscene

/* My app works as follows.
- User starts app.
- User chooses File->Open to select a file to render.
- App renders file.

createScene() builds the model after a user loads the file to be rendered.
createScene() is called within frameRenderingQueued().

The problem is that createScene() builds the model using vertex buffers (i.e., createManual()) and if it's in frameRenderingQueued(), then it will get called multiple times, and the second time it's called, it creates the model that's already been created (resulting in error).

Normally to create the scene, I'd have createScene() called within initialize() where it only gets called on started, but in this case, I'm adding a mesh during runtime.

Can anyone help with where I should add this, or point to any examples? The following is what I currently have.
*/

class QtOgreWindow : public QWindow, public Ogre::FrameListener
{
   ...
};

QtOgreWindow::render(QPainer* painter) { ... }

QtOgreWindow::initialize() {
 ...
}

QtOgreWindow::registerHlms() {
 ...
}

QtOgreWindow::createScene() {
    static bool called = false;

    Ogre::HlmsManager* hlmsManager =
        Ogre::Root::getSingleton().getHlmsManager();

    Ogre::HlmsDatablock* block = hlmsManager->getDefaultDatablock();

    Ogre::HlmsMacroblock macroblock = *block->getMacroblock();
    macroblock.mPolygonMode = Ogre::PM_WIREFRAME;
    block->setMacroblock(macroblock);

    if (called == false) {
        omesh = createStaticMesh();
        called = true;
    }

    Ogre::Item *item = ogreSceneManager->createItem(omesh, Ogre::SCENE_DYNAMIC);
    item->setDatablock(block);

    mSceneNode = ogreSceneManager->getRootSceneNode(Ogre::SCENE_DYNAMIC)->
        createChildSceneNode(Ogre::SCENE_DYNAMIC);
    mSceneNode->attachObject(item);
    mSceneNode->setPosition(Ogre::Vector3(0.0f, 0.0f, 0.0f));
}

QtOgreWindow::createCompositor() {
 ...
}

QtOgreWindow::render() {
 ...
}

QtOgreWindow::renderLater() {
 ...
}

QtOgreWindow::event(QEvent* event) {
 ...
}

QtOgreWindow::exposeEvent(QExposeEvent* event) {
 ...
}

QtOgreWindow::renderNow() {
 ...
}

QtOgreWindow::setAnimating(bool animating) {
 ...
}

QtOgreWindow::frameRenderingQueue(const Ogre::FrameEvent& evt) {
    cameraManager->frameRenderingQueued(evt);

    if (mesh_loaded)
        createScene();

    return true;

}

... mouse, wheel, key events ...