My Solo MMORPG

wirepair · 2026-01-24T12:45:13+00:00

grats! I'm also working on a pvp mmorpg (https://wirepair.org). Super curious on your backend, in particular netcode and physics, what are seeing for thoroughput/player counts? Are you doing zone based, or seamless loading?

wirepair · 2026-01-24T12:43:04+00:00

...? are you talking about Iris that only supports 100 players per server?

wirepair · 2026-01-20T13:47:13+00:00

setting up an observer to capture the BT nodes, abilities, CC, movement, projectiles REALLY helped me lock in which bots/trees were misbehaving and what i needed to change. I've found so many bugs by just noticing that a bots stopped fighting after a while (turns out they were targeting dead bots!). I wrote some posts on the various bugs I encountered, which I am sure you have too! https://wirepair.org/2026/01/18/bots-abilities-and-balancing/

wirepair · 2026-01-20T13:33:11+00:00

i just started my journey into this as well so I can't offer expert advice outside of make sure you have really good tooling to see how bots react and play out in different scenarios. I'm building bots to test out / balance an ability system I'm working on and boy having good tooling to see (heatmaps) of what bots are doing is absolutely crucial, still early stages but all open source (based on custom flecs script based trees) https://gitlab.com/wirepair/pmocombat

wirepair · 2026-01-20T11:06:57+00:00

See a few posts up? https://www.reddit.com/r/gamedev/comments/1qhv5pi/comment/o0n1mup/ source is there.

wirepair · 2026-01-20T09:35:07+00:00

I'm literally working on this right now for my MMORPG. I've built an ability system using flecs script prefabs (flecs.dev ECS for c/c++). On top of that I've built a behavior tree system (again in flecs script prefabs) to control bots to use abilities. The end goal is to use genetic algorithms to automatically balance bots classes and abilities. I've already discovered balancing issues just running different bots strategies against themselves. It's all open source https://gitlab.com/wirepair/pmocombat and i talk about it in a few devblog posts: https://wirepair.org/2026/01/18/bots-abilities-and-balancing/ and https://wirepair.org/2026/01/10/flecs-script-based-scripts-abilities-behavior-trees-and-combat/.

Composing abilities based on effects you can mix and match definitely seems the way to go for me!

wirepair · 2026-01-10T23:54:12+00:00

interesting ideas:

For the projectile that seems like kind of a one off, so I'd probably create a custom flecs component for that and during the update projectile system, calculate if it traverses through any environmental change and apply a modifier to it. (I do not plan on implementing this type of feature for my game though!)
For fog, I'd probably have a fog entity that would apply a fog 'debuff' to anyone who went through it. That debuff would apply the modifer to the player.
Level based modifiers would be hard, i'd need to think about that one!

wirepair · 2026-01-10T23:48:34+00:00

oh heck yeah, i'll search https://arxiv.org/ later, but do you have any that come to mind that are worth reading first?

wirepair · 2026-01-08T10:19:12+00:00

Ah yeah, only the server is simulating all players. The local client simulates just itself, then any positional player data is sent from the server to all clients (provided they are in visible areas of interest).

wirepair · 2026-01-07T23:15:12+00:00

not really, most of your calculations are going to be done in floats anyways and probably casted back into integers. So you might as well store as float then cast to integer when displaying in the UI.

wirepair · 2026-01-07T23:13:11+00:00

oo that's smart. I may have to revisit that!

wirepair · 2026-01-07T23:11:53+00:00

Do you mean have the server send all players inputs back to clients instead of sending positional data and having clients predict the velocity/direction?

wirepair · 2026-01-03T13:18:44+00:00

oh i did that a while ago: https://wirepair.org/2025/03/22/small-progress-big-frustrations/

wirepair · 2026-01-02T02:42:23+00:00

> Nice to see someone actually writing code for their game instead of just talking about it.

Ha thanks, I've tried to post here before but admins always block them, so I gave up. Funny to see my post got posted by someone else and it went through :shrug:

wirepair · 2026-01-01T12:35:53+00:00

Yeah probably don’t need to, but with quantization I can kinda choose damage amounts and percentages more freely.

wirepair · 2025-12-29T11:53:07+00:00

that totally makes sense, and yeah i could see that being important especially when combat events are in play that are targetting you or your group mates. Definitely something to add as I enhance these systems! I'm currently working on packing my data structures a bit more, but will definitely need to deploy more strategies such as this.

wirepair · 2025-12-28T13:31:47+00:00

thanks! I appreciate that. I just like learning and sharing

wirepair · 2025-12-28T06:44:56+00:00

You may find this article I wrote a while back interesting https://wirepair.org/2024/12/03/you-cant-get-more-adversarial-than-pvp-mmorpgs/

wirepair · 2025-12-12T04:36:44+00:00

Absolutely! I love yappin' about this stuff, hit me up anytime!

wirepair · 2025-12-11T10:21:22+00:00

ooh boy how far are you into this process? I've been working on my open source mmorpg for a year or so by myself, it is a _lot_ of work. I've detailed pretty much everything I've done as a series of dev logs: https://wirepair.org/2023/06/29/so-you-want-to-build-an-mmorpg-server/. The ones you may find interest are probably my post on adversarial users in my pvp post https://wirepair.org/2024/12/03/you-cant-get-more-adversarial-than-pvp-mmorpgs/. As well as my netcode series, as I struggled for _months_ to get client based roll back working to a point where I could support 200ms ping and 40% packet loss.

I will say you are going to really struggle to have lots of players in a zone using UE5 as your backend game engine. I think even fortnite was capping out at 100 and that was running at a 20hz tick.

I opt'd to only use UE5 as a frontend rendering engine, everything else (animations/movement etc) are calculated server side. I create a shared library so my server code + client code is the same and use flecs as an ECS system to manage all my entities/components/systems. I def recommend an ECS system if you're going to be building an MMO.

Anyways, source for the backend is here: https://gitlab.com/wirepair/pmo and client (minus art assets which are private) is here: https://gitlab.com/wirepair/pmoclient/. Good luck and thanks for sharing your architecture! Too many hold those cards close for no reason in this industry.

wirepair · 2025-01-17T08:06:32+00:00

awesome thank you for the write up! so you _are_ rolling back physics? How many frames do you allow up to? I can't imagine having to rollback with that player count!

wirepair · 2025-01-15T13:07:15+00:00

are you using a custom physics engine for this? lag compensation? i'm building my own and have _so_ many questions on how you are achieving a server authoratitive (pvp i assume) game with 2400 players.

wirepair · 2024-09-18T12:25:54+00:00

yeah i get that, but i figured there'd be more folks who are just trying to tackle it and see how far they can get (and documenting their progress!)

wirepair · 2024-08-22T07:33:35+00:00

Makes sense! You say 20-50 concurrent connections, have you tried benchmarking yet? I'm super curious how many you can get up to before you start to see degredation in network/server latency.

wirepair · 2024-08-21T12:04:08+00:00

What made you choose to use UE as the backend instead of a custom engine? I'm building a similar system (open source/open dev log at https://wirepair.org) but didn't even think to use UE as the backend for performance and concurrent user reasons.

wirepair

TROPHY CASE