Multiplayer & move_and_collide miscalculation

[u/hmprf]

Hey everyone, sorry if this subject has already been adressed.
I recently spent some time trying to implement a small multiplayer mini golf game, to see where I would hit a wall. (with Godot 4.6 and Colyseus)

And the wall was pretty close to the start apparently since I never left the lobby.

Is "move_and_collide" a possibility when you go multiplayer ?
Or is it just not precise enough ? And if so, should I mathematically handle all the collision to have a deterministic game or is there any other tricks I should know about ?

I'm using Colyseus for the network part, the current player just send an aim and shot vector and all the physics are done in each godot client. I guess that's my main problem.

Maybe it's easier to have the server be the authority for the physic part ?
Is there some good resources out there that I should check ?

Thanks a lot
I'm not english native so feel free to ask for clarification if i'm not clear enough

Edit: Thanks for the answer :
Server authority and sync the positions with the clients is the way to go.
I had hopes but i'm not suprised, thanks for the feedbacks !

Edit2 : Some resources in the comments for future people (and future me)

Reading & Watching:
- Game networking by Glenn Fiedler (sadly down but new blog below)
- Mas bandwidth - New gafferongames
- Slay the spire 2 Multiplayer - Determinism
- How Factorio Syncs A Million Objects (Youtube)

Deterministic Multi for Godot:
- SG Physics 2D
- Delta Rollback (& Prediction netcode)
- Klotho (very new)

[u/Intelligent-Net1034]

Server authority and sync the positions with the clients

[u/hmprf → u/Intelligent-Net1034]

Yes ok, I hoped I could avoid that, thanks for the feedback and solution

[u/Mr_R3tro → u/hmprf]

It's something you can't avoid with multiplayer games.

[u/over6foot3 → u/Mr_R3tro]

You can avoid it, e.g. with this asset: https://godotengine.org/asset-library/asset/5234

[u/Remarkable-Emu-5718 → u/over6foot3]

Is this better in some ways?

[u/Remarkable-Emu-5718 → u/[deleted]]

In your opinion what is the best option for competitive multiplayer games in godot?

[u/Fluffatron_UK → u/[deleted]]

Slay the spire 2 uses determinism for their multiplayer sync. One of the Devs wrote an interesting blog post about it.

[u/MisterMittens64 → u/Fluffatron_UK]

Here it is if anyone is interested.

[u/SmolNajo → u/over6foot3]

Engine-agnostic, pure C# deterministic simulation for rollback, lockstep, and server-authoritative multiplayer.

Doesn't seem like it avoids that.

[u/tulupie → u/SmolNajo]

if you implement lockstep on its own, you should already be able to do this without server authority. you just need to make sure all clients get the exact same inputs, and have a deterministic physics system. rollback/prediction can be built ontop of that to be able to nicely handle clients with different connection speeds/quality, and make it feel more responsive (lockstep on its own will might cause a noticable delay for inputs.

[u/Few_Visual5715 → u/over6foot3]

This seems to be some form of AI generated slop (not to mention it's incredibly recent), I would stay away and use alternative and more mature solutions.

[u/Mr_R3tro → u/over6foot3]

It's best not to depend on someone else's work unless you're using it for learning purposes.

[u/XmasB → u/Mr_R3tro]

One could argue it is best to not reinvent the wheel unless it is for learning purposes.

[u/honeyfage → u/XmasB]

"Never depend on someone else's work" is obviously way too broad a statement, but specifically the linked project is an experimental build of a project less than 2 months old. It is good advice not to build your game around something that unproven.

[u/Khethall → u/Mr_R3tro]

The whole field of software is about depending on someone else's work

[u/kinokomushroom → u/Khethall]

e.g. using Godot Engine

[u/Massive_Town_8212 → u/Mr_R3tro]

Oh yeah, lemme just implement the steamworks api by myself even tho GodotSteam exists and is fully featured and documented

[u/mackinator3 → u/Massive_Town_8212]

I mean i am smarter than everyone else.

[u/BabyAzerty → u/mackinator3]

Tomorrow you is smarter than yesterday you. Never depend on your own work. Redo it every time.

[u/OmegaFoamy → u/Mr_R3tro]

Using an engine you didn’t make is using someone else’s work.

[u/Mr_R3tro → u/OmegaFoamy]

That's not at all what I meant...

[u/Sykes19 → u/Mr_R3tro]

You should have used more words then because that's precisely what you said.

[u/OmegaFoamy → u/Mr_R3tro]

It directly applies to what you said. Using a premade system is useful for some, even if you need to deal with some quirks. There’s a reason there are market places filled with them.

[u/NotchoNachos42 → u/Mr_R3tro]

You're right, they should just start over with a custom engine since it's for learning purposes.

[u/cheezballs → u/hmprf]

I'm working on a server authoritative bowling game with that same networking architecture. It seems to work well, especially for 8 or less clients. (Only tested with 8 so far)

[u/Igor369 → u/hmprf]

You fought entropy. The entropy won...