So I’ve been slowly implementing basic multiplayer to a demo project of mine, currently nothing special. I’ve made a few games in singleplayer and have a decent grasp on the engine in that regard, and so far things are going well with my demo project. Outside of Godot I have limited experience in networking, and often when studying multiplayer I read comments in regards on how some people will try to use games to compromise other users PC’s and it’s made me paranoid on continuing to learn how to develop multiplayer games.
Before I become dedicated in attempting to make a multiplayer game, I wanted to know some not-so-obvious do’s and don’ts you may have in regards to creating a multiplayer game? I understand you want to put as much as you can behind the server and to trust the client as little as possible, but is there more to it than that? What are some ways to avoid making a product that can compromise user’s computers? Are the official starter documentation guides to developing multiplayer games in Godot safe ways to begin a multiplayer project? I worry that because I am not savvy enough with networking that I will miss something fundamental and cause harm to hypothetical/potential players.
Thanks for any response
Actually I started a Multiplayer project quite some time ago (and never finished it to this day 🥲)
The tricky part about multiplayer in godot is not handling network connection stuff because this is done by Godot itself and you do not need to know anything about TCP or UDP and this technical stuff, although it does not hurt to know some background. So Godot is utilizing something called ENet-Protocol to implement Remote-Procedure-Calls (RPC).
That means you can call functions over the network in other instances of your game running. And from this 2 tricky things emerge. The first is that you need to construct those functions in a way that they cannot be exploited, not in an cheater manner and not in a system security manner (as long as you don’t have any file system access in those functions at least the security aspect should be very easy to fulfill)
The other tricky part begins when you want your network game to be played outside of a fast Local Area network (LAN) and be playable in the open world of the internet. Because not only will you be forced to provide some sort of infrastructure enabling your game instances communicating from within a players local network with another instance in another local network, additionally packet travel time is becoming significantly worst and data lost must be assumed. So you need to structure the interaction of the game instances in a way to handle this. Basically you will need to predict what will happen in clients before you will receive any a definitiv answer and then maybe addapt to this answer without the player noticing this…
The following articles I found very helpful for understanding problems some might encounter while make a multiplayer game: https://www.gabrielgambetta.com/client-server-game-architecture.html
Also this videos I think are usefull to understand the concept of RPC and Multiplayer in Godot better. Please note that a older Godot version is just in there and the syntax has slightly changed by now but the concepts remain the same: https://www.youtube.com/watch?v=d8QpnamQq1A https://www.youtube.com/watch?v=lnFN6YabFKg&t=1s
And like always the Documentation also has somthing to say about this: https://docs.godotengine.org/en/stable/tutorials/networking/high_level_multiplayer.html
Some more tips to get you started: If you not already using it consider the Godot CLI to setup multiple instances of your game for debugging this is quite handy. https://docs.godotengine.org/en/stable/tutorials/editor/command_line_tutorial.html
And of course you could just skip all this RPC/Enet stuff and start implementing your own network calls but I don’t think that this is really worth the trouble for 99.9% of the use cases.