Update only when, and just prior to, rendering, giving no opportunity to interleave unexpected state changes. This means that every time anything about the state is changed, we'll have to attempt a render to reflect that change. In the case of continuous rendering this has happened before this change as well, but it leaves no room for time to pass between an update and a render. In the case of still image rendering, a render call will only actually paint something to the view when all resources have been loaded.
b6894dd4fc