Nice! I’ve been (slowly) working on a World of Warcraft server, Thistle Tea, that has some similarities.
In Thistle Tea, players and NPCs are processes, but I’ve abstracted the interface to use GUIDs. The idea is that the boundary process layer will be straightforward enough to swap for something that groups entities by zone instead if it ever becomes necessary, without needing to change (much) game logic code.
IO lists are a good idea, they’ve been on my list to benchmark sometime but haven’t got around to it. Right now building packets is just binary concatenation. Bandwidth measurements are a smart idea, I have latency metrics but bandwidth would helpful to understand the entire system performance.
I’m also using ETS for a spatial grid and it’s been working really well. Recently also started using ETS for per entity metadata that other processes need access to in hot loops, that seems to work decent to avoid the message passing overhead where necessary.
I’ve mostly been focusing on building out functionality, recently got a rudimentary NPC AI wired up using behavior trees to get the basics of combat working. Stuff’s tricky because the client really likes crashing if packets are even slightly malformed, and some of the expected packet layouts aren’t very clear, lol.
It uses a Rust NIF for pathfinding, which would’ve been a pain to implement from scratch. Still a bit of wonkiness there for me to debug sometime, though. Mobs like to stutter around a bit when repathing, which makes me think the server isn’t perfectly simulating movement the same way the client is (or some other bug).
Here are a few blog posts I wrote about the process if you’re interested.
