public static void startApp() {
   app.startCanvas();
   app.enqueue(
       new Callable<Void>() {
         public Void call() {
           if (app instanceof SimpleApplication) {
             SimpleApplication simpleApp = (SimpleApplication) app;
             simpleApp.getFlyByCamera().setDragToRotate(true);
           }
           return null;
         }
       });
 }