How do I pass keypress events to QQuickFramebufferObject::Renderer?

While you can handle key presses in the renderer using signals, it isn’t exactly a clean separation of rendering and other logic. Ideally the renderer, that operates on the render thread, would perform rendering only based on the state it receives in the synchronizing step. All other logic, like handling key events and updating the state based on them, should stay on the gui thread. The state is then transferred in synchronize().