Although not yet released, I am trying to make sure that committed versions are runnable, so if you want to test out the system, simply follow the installation instructions. Note that the function definitions are still subject to change, but any rooms you build should be compatible with later versions.
The basic system is working, I am now currently working on shadow casters. In a simple system you would pre-bake your lighting with e.g. lightmaps, however with realtime lights, shadow casters outside the view of the camera can cast shadows onto the objects in view. Rather than rendering everything as a possible shadow caster, it makes sense to use the same room / portal system to cull out as many shadow casters as possible that could not contribute to the final image.
Note that I've had to move from showing and hiding objects, to using Godot object and camera layers to differentiate between which objects to render from the camera and which for shadows, at least for now. This is a little hacky, and might interfere with your own code if you are using godot layers - layer 1 (default layer) is unset for all objects, and 19 and 20 are currently used by the system to determine whether objects are shadow casters or visible (or both), respectively.
