[ItsFirefly]

Angeldust has practically zero level of detail (LoD) and has no occlusion culling. "Almost zero LoD" means that geometry is always rendered at full resolution, but subtle vertex-shaded effects like the waving of grass are not applied for distant geometry. So you will see grass everywhere, but it won't wave when it's "unnoticeably" far away. Other than that I just push millions of mostly buffered triangles and vertices each frame at high view distance without a hitch. Turns out computers are pretty fast these days.

Note that I'm working on a newer render engine that actually uses more GPU shading capabilities and this engine runs even smoother than the current one, since it balances the workload a lot better between CPU and GPU.

As for data structures: both client- and server-side it's pretty much a simple std::map<coordinate, chunk*>. Its O(log(n)) lookup is adequate and I don't want or need to do complicated things to ensure decent performance. On top of the map I do spatially-aware caching to prevent say 99% of actual map lookups which turns the majority of lookups into O(1) which seems pretty much optimal.

As for keeping data: the server is authoritative in everything. The server keeps the data. You can take any device, install Angeldust and sign in with your credentials and you'll find yourself back in the same world, same friends, same progress, same everything that you had on another device.

Same with game state: the server tells the client everything. The client is basically just a dumb graphical terminal application that renders 3D visuals instead of VT100 text.