Reminds me of Marathon's non-euclidean maps. The engine traversed adjacent portals to determine what polygon-based cells to draw/interact with. Very mind bending in its day. Some of the multiplayer maps make strong, obvious use of this, if memory serves.
In fact, apparently the entire series is open source and free to play: https://store.steampowered.com/app/2398450/Classic_Marathon/
Highly recommend checking it out.