Show HN: Moongate – Ultima Online server emulator in .NET 10 with Lua scripting

This is such a good observation. UO had a real economy and social hierarchy because power wasn't handed to you. You could spend months as a fisherman or tailor and still have a meaningful experience. The gap between a grandmaster swordsman in full plate and a guy selling fish at the Britain bank was enormous, and both of them were having fun.

Modern MMOs are theme parks where everyone gets the same ride (with pay per win). UO was a living world where your role emerged from what you chose to do, not from a quest marker telling you where to go next.

Being a legendary blacksmith was the whole point. Where crafting was the end game state for crafters. The gear produced was max durability, max dmg, max armor rating. The furniture for your castle had to come from someone, somewhere.

The whole point of the game was to live in this fantasy world, not beat it. There were no quests. No antagonist. Just good and evil and everyone in between. For once I wish a studio would take this to heart and build something like that again. Minecraft exploded due to this sandbox nature. However, you still got to give players a shovel and a bucket.

UO was the best online game for me. All others stand in its shadow. It was the most "free" in terms of what you could do and the appeal was the non-gamification.

I loved Everquest and World of Warcraft but those didn't feel "raw" enough for me.

The Realm is my dark horse submission for best MMO. (Yea, yea, yeah Meridian 59 and Underlight too)

I'll forever chase the dragon that is the joy of playing UO. I want to quit my job and play it 24/7.

yes, this really nails it. UO didn't chase "endgame content" which, imo, is the bane of today's multiplayer games. Designers expect everyone to max out and reach the end of the road so everyone is the same in the end.

Sounds like Vanilla WoW before Blizzard killed 40 man hardcore raiding. Only a few guilds on the whole server had the top gear.

Yup. Tibia you had this too. People begging in the depot for gold and "itens plx"

Was it actually that hard?

I played on the JP/KR asian servers in a PK/APK/PVP guild so maybe it was just my bubble but it was pretty common to see players with 7 skills maxed out. If I remember correctly

- sparring

- swordsman or fencing

- magic

- magic resistance

I don't remember the rest. It's not quick or easy like modern games, but we would regularly power level each other's alts and it took maybe 2 weeks to max out all 7 skills? We had a bear trapped in the guild house so we could power level wrestling and other combat skills.

So: I took most of the infrastructure from the my first attempt at moongate (https://github.com/moongate-community/moongate, which failed miserably along with https://github.com/tgiachi/Prima). From there, I had a good starting point to quickly build the foundations. I had already done the Lua scripting part in another project (https://github.com/tgiachi/Lilly.Engine). Codex helped me with all the testing, implementing functionality and creating tests, so at least I have a good sparring pattern. For the data import part (which I called FileLoaders), I took the logic from ModernUO. For the items part, I created a script (scripts/dfn_*.sh) to import items from POL! Thanks for the compliments! The way I am, if I fixate on something, it becomes an obsession!

I forgot to mention, the entire web part in React was done by Codex. I hate developing frontends!

Hey, I am just reaching out to say: "thank you."

When I was in high school, I played a lot of UO. It was actually the last computer/video game I ever played regularly, because I convinced myself as a teenager that I was addicted to it and needed to drop it "cold turkey" to focus on academics and extracurriculars.

(A sign of the times for the late-1990s nostalgics: I sold my UO account on eBay for a few thousand dollars and an MTG Mox Pearl. I owned a bunch of virtual real estate, e.g. a UO tower on an island only accessible via moongate. The high bidder "threw in" a Mox Pearl as a kind of informal escrow, to make sure I completed the account transfer after getting paid.)

Before I dropped UO from my life, I discovered UOX. I was learning C++ and UOX was a great way for me to practice my emerging C++ skills.

My clearest memory of feeling the power of programming was when I created a mod for my UOX server that allowed me to drop an unlimited number of interconnected and color-coded moongates all over my server, creating something akin to the feeling of the game "Portal," but long before Valve released "Portal."

It was after having a blast with UOX that I decided to dig into programming much more. Somehow, the UOX server mod made programming feel "real" for me in the way my prior forays into coding simply didn't.

That led to me learning Python -- as a way of toying around with the Slackware Linux server I had in my basement. I left C++ behind, but it was an important stepping stone for me. Now, decades later, learning Python was probably the single most important decision of my life in childhood. (See e.g. https://amontalenti.com/about)

UOX is such a cool project. UO was a really ahead-of-its time internet game, as well. Great memories. Thank you.

That’s awesome to hear! Actually UOX3 is one of the inspirations behind Moongate. The way it approached the server architecture and scripting was really interesting and it influenced some of the ideas I’m exploring in the project.

Projects like UOX3 are a big part of the history of the Ultima Online emulator scene, so it’s great to hear from someone who helped maintain it.

Thanks! Yeah, one of the main motivations was exactly that — after years working with legacy UO codebases where networking, persistence, and game logic were deeply intertwined, I wanted to see what a clean-slate approach would look like with modern .NET.

On sector sync bursts — this is something I'm actively tuning. Right now when a player enters a new sector, we sync all ground items and mobiles in the surrounding sectors (configurable radius). For busy areas that can mean a lot of packets at once. The current approach is:

  - Sector enter sync only sends the delta  sectors the player wasn't already seeing, so a simple move into an adjacent sector doesn't resync everything
  - Sectors close to the player (within 1 of center) are always resynced because the UO client silently drops items beyond its visual range (~18 tiles), so you need to re-send them when the player comes back
  - The outgoing packet queue handles the actual send, so the game loop isn't blocked waiting for network I/O

  That said, there's definitely room for prioritization (mobiles first, then nearby items, then distant items) and spreading the sync across multiple ticks instead of one burst. It's on the roadmap.

  On NativeAOT — honestly, both. The single-binary deployment is great for Docker (small image, instant startup), but the real win is predictable performance. No JIT warmup, no tiered compilation surprises
  mid-session. For a game server where you care about consistent tick timing, eliminating that variable is worth it. The tradeoff is you lose some runtime flexibility, but source generators fill most of that gap
  (packet registration, serialization, etc.).

>Curious about the sector-based delta sync — how do you avoid packet bursts when a player enters a busy area with lots of items and mobiles?

doesn't look like there is much going on to protect packet bursts there aside from smart-ish proximity sector loading. the work is done at boundry.

dove into it because i have been recently working on frustrum spawning to reduce net burst in a similar project, was kind of curious if something similar was used as a method to pre-warm the upcoming sector but I didn't catch anything.

fun and easy to read. thanks op and parent for getting me to look through it.

This is a very fun idea. Would also be very interesting to see if one could have a system where talking to an NPC could alter the world.

One maybe obvious way would be that asking for rumors will actually creates the scenario that the NPC describes.

I am interested please write me on GitHub!

Thanks! The logo was a happy accident. I wanted something simple that felt like the moongates (so and so :) from the original game. I'm not really a video person. But here's what's working today: login flow, character creation, world movement with delta sector sync, auto-generated doors from map statics (that actually open), Lua scripting for item behaviors, snapshot persistence, and a React admin UI for server management.

I'll probably add a short demo gif or video to the README at some point, but for now the best way to see it is to clone it and run it

Ultima Underworld is a fantastic game.