Show HN: Server-rendered multiplayer games with Lua (no client code)

[brunovcosta]

Hey folks — here’s a small experiment I hacked together over the weekend:

https://cleoselene.com/

In short, it’s a way to build multiplayer games with no client-side game logic. Everything is rendered on the server, and the game itself is written as simple Lua scripts.

I built this to explore a few gamedev ideas I’ve been thinking about while working on Abstra: - Writing multiplayer games as if they were single-player (no client/server complexity) - Streaming game primitives instead of pixels, which should be much lighter - Server-side rendering makes cheating basically impossible - Game secrets never leave the server

This isn’t meant to be a commercial project — it’s just for fun and experimentation for now.

If you want to try it out, grab a few friends and play here: https://cleoselene.com/astro-maze/

[kibbi]

Interesting approach! I've thought about a similar method after reading about the PLATO platform.

When playing astro‑maze, the delay is noticeable, and in a 2D action game such delays are especially apparent. Games that don’t rely on tight real‑time input might perform better. (I'm connecting from Europe, though.)

If you add support for drawing from images (such as spritesheets or tilesheets) in the future, and the client stores those images and sounds locally, the entire screen could be drawn from these assets, so no pixel data would need to be transferred, only commands like "draw tile 56 at position (x, y)."

(By the way, opening abstra.io in a German-language browser leads to https://www.abstra.io/deundefined which shows a 404 error.)

[brunovcosta]

Yeah.. As people are playing and I'm watching their feedbacks it is becoming clear to me that the main source of input delay comes from the distance to the server.. the whole game is running in a single machine in SFO, so it makes total sense this bad exp in europe

I think this is inevitable unless I add some optimism/interpolation in the client

Also, thanks for the feedback! I will fix the Abstra landing page

try https://www.abstra.io/en instead

[fionic]

Cool! Besides the productizing or making a framework, I’m trying to understand if this is different than the elementary idea (which probably every game dev who worked on game networking has tinkered with) of sending inputs to the server and then sending player positions back to all the clients…? I think even smaller footprint would be position: two or three floats x,y(,z) instead of shapes too? Anyway this is always fine for very low latency environments where client side prediction, lag comp etc would not be required. Thanks for sharing, I might give it a try! sorry if I’m missing something.

[brunovcosta]

You're correct

My approach lives in some place between video streaming and data streaming in terms of performance

It's not intended to be faster than a proper client that brings a lot of logic and information that diminish the amount of information required to be transfered

My proof of concept is more about: Can my dev exp be much better without relying on the video streaming approach? (which is havier)

[ghxst]

IMO eliminating as much client side authority as possible is a very good foundation for MMOs where the latency is acceptable or factored into all aspects of the game (looking at old school runescape as an example). Very cool project!

[brunovcosta]

Thank you!

[Matheus28]

Client-server multiplayer games are already kind of a very specialized type of video playback if you squint a bit (you're transmitting entities rather than pixels).

This method of multiplayer you propose is inferior in basically every way: you can't do client-side prediction to make inputs feel smoother, and non-trivial scenes will surely take up more bandwidth than just transmitting entity deltas.

[Thaxll]

"Impossible to Cheat"

Let me tell you that there is cheating in cloud rendering solution ( Stadia, AWS Luna ect ... )

So 100% there is cheating in your solution.

It's trivial to read the screen.

[brunovcosta]

You're right

Especially with today's computer vision

The cheating I'm more protected (just as stadia, etc..) is regarded to client/code exploitation

which we don't have to worry about in this approach

[allthatineed]

BYOND/Space Station 13 is built upon this model.

Sprite sheets are png with ztxt blocks with meta/frame info and a list of drawing operations to be done to construct vsprites based on any runtime server side operations done on the sprites.

There is limited client coding via popup Web view windows and a few js apis back to the client but nothing you can build too much off of.

(SS14 brings this model to an open source c# framework called The Robust Engine but has some limitations related to maintainer power tripping over who should be allowed to use their open source project.)

[brunovcosta]

Amazing! Never heard of this byond/ss13/14

Thank you for the reference!

[aetherspawn]

The latency is a little intense from Australia … but surprisingly not as bad as I thought it would be.

It was playable.

I wonder if you can use speculative execution to play the game a few frames ahead and then the client picks what to display based on user input, or something like that.

Each frame is 16ms, so you’d have to work ahead 6 frames to conquer the nominal latency of around 100ms, which may actually be 200ms round trip.

(In that case, something like Haskell would be a good candidate to build a DSL to build the decision tree to send to the JS client…)

[lurkshark]

What you’re describing is called “rollback netcode”. It’s a pretty cool chunk of theory, usually used for fighting games which are extremely sensitive to latency. This explainer has some nice graphic demos

https://bymuno.com/post/rollback

[Neywiny]

It could help visually but you'll still have 200ms between you and your next door neighbor's actions

[modinfo]

Im just vibe-coded a multiplayer game with deterministic terrain world generation with Cleoselene in 5min.

https://github.com/skorotkiewicz/proximity-explorer

[brunovcosta]

That's AMAZING!

I will definitively follow that!

[efilife]

Was it really 5 min or more like 30?

[RodgerTheGreat]

I had a similar idea about 13 years ago, but I didn't extend it into a generalized game engine: https://github.com/JohnEarnest/VectorLand

[6r17]

Cheating with AI will be possible even with server side rendering ; nvidia has released models able to learn to play - it's going to be very difficult to detect whether it's an AI or a human ; very impressive however

[nkrisc]

That’s a very different kind of cheating though. The kind of cheating this effectively makes impossible is cheating where a player has more information than they’re intended to have.

If someone makes an AI that plays the game as a good player, then it’s effectively indistinguishable from a real player who is good. If they make it super-humanly good, then it would probably be detectable anyway.

It’s still fair in the sense that all players have the same (intended) information per the game rules.

[tnelsond4]

Since you're doing this is rust, try experimenting to see what would happen if you did zstd compression using a dictionary on the data you're sending back and forth, it might give you a performance benefit.

[brunovcosta]

I will definitely try it!

I'm using Gzip since it comes with all browsers hence a easy approach

That said, I will find som zstd decompressor for js/wasm and try!

edit:

I just added and the difference was huge! Thank you!

[2001zhaozhao]

> - Streaming game primitives instead of pixels, which should be much lighter - Server-side rendering makes cheating basically impossible

This doesn't work in 3D. Unless you have the server do the work of the GPU and compute occlusion, you'll end up sending data to the client that they shouldn't be able to have (e.g. location of players and other objects behind walls)

[nkrisc]

Theoretically couldn’t you send each client its data after performing occlusion culling based on each one’s camera?

Don’t some competitive games more or less already do this? Not sending player A’s position to player B if the server determines player A is occluded from player B?

I seem to recall a blog post about Apex Legenda dealing with the issue of “leaker’s advantage” due to this type of culling, unless I’m just totally misremembering the subject.

Regardless, seems like it would work just fine even in 3D for the types of games where everyone has the same view more or less.

[cmrdporcupine]

"We stream drawing primitives instead of heavy pixels or complex state objects."

This is cool ... but I suspect just pushing video frames like Stadia etc did is just as efficient these days and a lot less complicated to implement and no special client really needed. Decent compression, and hardware decode on almost every machine, hardware encode possible on the server side, and excellent browser support.

[MarsIronPI]

On the other hand, you could take a list of primitives from, say, the JS Canvas API, come up with a format that can encode all of them and use that as your protocol. Bam, with that you get one client for any game that uses JS Canvas.

[ftgffsdddr]

Is the source code available?

[efilife]

Doesn't seem like it

[emmelaich]

Reminds me of the cave X11 games. For game play I'd suggest slowing it way down.

[brunovcosta]

good feedback! I'm seeing people really struggly with the control lag + speed.

I'm always biased since I test locally with no delay when developing :)

[chasebrignac]

Sick! And the game is fun too! I’m sending to my brother who is a junior game dev.

[ycombinatrix]

Is this how Stadia was supposed to work?

[brunovcosta]

Not exactly, since they aren't opinionated in the game engine, they can't control what "primitives" are being used to render.. they probably just encode video

[ingen0s]

Might be the greatest thing I have seen made in like 10 years

[duduzeta]

Cool!! I'm trying to test here, but other ships keep attacking me and I don't know how to shoot :s

[brunovcosta]

Amazing! hahaha.. Tip: Arrows + Z (shoot)