public static void createActivity(Activity activity) {

		if (killCurrentActivity)
			killCurrentActivity();

		if (!stack.isEmpty()) {

			Activity previousActivity = stack.peek();

			stopActivity(previousActivity);
		}

		stack.push(activity);

		activity.onCreate();
		startActivity(activity);

		if (activity.getView() == null) {

			stack.remove(activity);
			stopActivity(activity);
			try {
				throw new Exception("A view must be created");
			} catch (Exception e) {
				e.printStackTrace();
			}
		}

		if (activity.getRenderContext() == null) {

			//2d ortho projection
			Mat4 projection = Projection.ortho(
					0, activity.getView().getWidth(),
					activity.getView().getHeight(), 0, -1, 1);
			activity.setRenderContext(new RenderContext(new GUICamera()));
		}

//		activity.rebuildModel();
	}