[WIP] Add Multiplayer Example #905

ValorZard · 2024-09-23T22:05:22Z

Add multiplayer example!
heavily inspired by -> https://youtu.be/e0JLO_5UgQo?si=cauEVPrbe6ThtDTh
Fixes #903
pretty simple, but i do want to add some quality of life stuff

Also, we need to replace the old assets with better ones, since the ones I used have a weird license

…w. Hoping that converted the rest to Rust will fix it

GodotRust · 2024-09-24T07:29:24Z

API docs are being generated and will be shortly available at: https://godot-rust.github.io/docs/gdext/pr-905

ValorZard · 2024-09-24T08:08:28Z

Okay, so, spent all of today working on this, and I would love some fresh eyes.
I got the connection to work (ish) with a dedicated server mode.
However, for some reason, if you connect too fast, the game bugs out. Not sure why, probably something to do with the connection or game scene not initializing yet.
Tried to keep it as simple as possible, but I did attempt to add an actual game into this, by giving players health and the ability to shoot each other. When they die, they should respawn in a random location.
Really hope the code makes sense. I largely followed the code in FinePoinCGI's git repository, but cleaned it up and tried to make it sane.

To test this:

Open up two or more clients.
Choose one of them to be the host and click "Host"
On all the other clients, click "Join"
Wait a second or so, for some reason if you click start game too fast it doesn't work
Once everyone is linked up, click "Start Game"
Have fun!

In order to test dedicated server mode, run one of the clients with the arguments "--headless --server" and all of the other clients click "Join"

I would REALLY appreciate the help on this PR, this was a lot more complicated than I thought. Multiplayer is hard!

ValorZard · 2024-09-24T08:18:29Z

I just realized that instead of randomly choosing a spawn location, I could have just saved the spawn point the player originally came from, and then just make the player respawn there on death. Though, that wouldn’t be as fair…

Bromeon · 2024-09-24T08:43:49Z

Thanks a lot for all your work on this, a little multiplayer demo sounds like an amazing addition 🙂

I'll give it more detailed review when out of draft, but some initial feedback already:

Instead of "WIP" in the title, you can create the PR as a draft (I converted it now). Later, you can mark it as ready. For this, please make sure the following are fulfilled:
- CI is green. There is check.sh for local checks.
- Contribution Guidelines are followed, especially number of commits.
Please don't change unrelated code like the dodge-the-creeps example.
The GDScript code is just needed during porting phase, right? Shouldn't be part of the final example.
Examples should focus on mostly one area of the engine or feature set and not try to pack as many features as possible. The reason is that the latter increases complexity and the time it takes for users to understand the code. Concretely:
- There are some java-esque patterns like SceneManager and GameManager. Can we combine the two classes? How would a design look that doesn't require singletons? I don't want to promote this pattern in an example, especially since it's not yet thread-safe.
- Do we need a massive animation setup and texture atlas? A minimal animation can be nice for visuals, but having dozens of frames adds nothing to the understanding of multiplayer.
As mentioned on Discord, all assets must have a clear license, preferrably Creative Commons and preferrably no restrictions on commercial use.

I haven't run it yet, is the game currently already playable?

ValorZard · 2024-09-24T08:55:53Z

In order

Cool! Didn’t know that
That was totally by accident haha
I forgot I still had GDScript in there, I’ll need to remove those and some other stuff in there like the non-creative common assets and some test scenes I can delete
Yeah we can remove the animation stuff, and honestly the player can just be a static sprite. I was thinking we could maybe reuse some of the assets from dodge the creeps actually, but idk.
Also, I’m not really sure how to get this working without the two managers to be honest. I’d love to hear feedback on better ways to design this!

Also, as mentioned earlier, this is playable right now! It’s just a little buggy for reasons I can’t quite grasp yet. I wrote up instructions in an earlier reply.

Bromeon · 2024-09-24T09:06:55Z

Do you think you could merge the 2 managers to 1? Maybe I can then see if there's a way to architect it differently.

Cool to hear it's playable! I don't know when I get around to test it out, but probably not today 🙂

ValorZard · 2024-09-24T09:11:16Z

Actually, I just realized that it’s totally doable. GameManager is essentially just a wrapper class around a hash map, and I could move that hashmap into SceneManager itself!

ValorZard · 2024-09-24T17:32:01Z

Alright, did some cleanup, and GameManager is now removed! Horray! we just pass around the hashmap containing all the player data now. Only problem is, the connection is still really inconsistent. I think its because the test scene spawns at different times for all the different clients, which leads to desyncs. Not really sure how to solve this, will need to look into this more.

ValorZard · 2024-09-24T17:49:47Z

Some more assorted thoughts:
Setting spawn points and respawning players should all be done on the server side. Player will probably have a function called set_global_position_from_server() that is an rpc that can ONLY be called from server side, and sets both the sync and global position to whatever the server wants it to be.
There should also be a function in SceneManager called spawn_players() that is an RPC called to the server during ready(), where the server spawns all the players in the spawn points.

… now

…dd callback for hitting bullet on player

ValorZard · 2024-09-24T23:35:31Z

Yeah, im officially going to need some help with this.
From what I understand, SOMETHING is going horribly wrong, and I'm at the point where I think I would really appreciate someone else testing this out and looking at the code. All of the other issues (singletons, asset replacement) has been address.
Here's what the current problem is:
Sometimes, if you start the game too fast right after all clients connect, things horribly desync and I have no idea why.
I've tried debugging and refactoring, and while it looks like it may have helped with making the code more sane (or at least I hope so), the bug is still there and I literally have no idea why. This was never an issue with the GDScript version, and I'm starting to suspect some bizarre thread stuff is going on here with the Rust bindings.
This is where I stop for now, feel free to test it out and tell me your thoughts!

To test this out:

Click Customize Run Instances

set up the instances like so

click run

click join on both clients

once both clients are connected, click start!

it will sometimes look like this

and other times it will look like this

this error keeps popping up and I can't tell where

(Feel free to convert this back into a draft, I thought I was done but HO BOY)

Yarwin · 2024-09-27T08:44:05Z

Cargo.toml

@@ -13,7 +13,7 @@ members = [
    "itest/rust",
    "itest/repo-tweak",
    "examples/dodge-the-creeps/rust",
-    "examples/hot-reload/rust",
+    "examples/hot-reload/rust", "examples/multiplayer-lan/rust",


you forget newline

Yarwin

I left some comments. I'm not too experienced when it comes to networking with godot so I focused purely on godot-rust side of things. My main issue – why don't we just use one of godot's examples instead of frozen-in-time youtube video? Who is going to maintain this example and make sure it is up-to-date with latest changes and best practices?

Yarwin · 2024-09-27T08:45:23Z

examples/multiplayer-lan/rust/src/multiplayer_controller.rs

+
+const LOCALHOST: &str = "127.0.0.1";
+const PORT: i32 = 8910;
+#[derive(GodotClass, Clone)]


Why does it derive a clone? Shouldn't it be passed around using Gd smart pointer?

Yarwin · 2024-09-27T08:46:47Z

examples/multiplayer-lan/rust/src/multiplayer_controller.rs

+        Self {
+            address: LOCALHOST.into(),
+            port: PORT,
+            game_scene: PackedScene::new_gd(),


… do we really want to create PackedScene::new_gd() instead of using an option? Not filling this property might lead to weird behaviours

fixed this, you're right

Yarwin · 2024-09-27T08:47:36Z

examples/multiplayer-lan/rust/src/multiplayer_controller.rs

+}
+
+#[derive(GodotClass)]
+#[class(base=Control)]


does it need custom init really? Can't we use #[init(default = …]?

ill be honest, i dont know what you mean by this

Yarwin · 2024-09-27T08:48:12Z

examples/multiplayer-lan/rust/src/multiplayer_controller.rs

+    address: GString,
+    port: i32,
+    #[export]
+    game_scene: Gd<PackedScene>,


Why not option? What will happen if this property won't be filled? Why isn't it commented to inform user about your design decision?

Yarwin · 2024-09-27T08:49:36Z

examples/multiplayer-lan/rust/src/multiplayer_controller.rs

+
+#[godot_api]
+impl MultiplayerController {
+    // called when a new "peer" gets connected with the server. Both client and server get notified about this


/// for docs.

Yarwin · 2024-09-27T09:06:28Z

examples/multiplayer-lan/rust/src/scene_manager.rs

+
+    /*
+    #[func]
+    fn respawn_player(&self, &mut player: Gd<Player>)


leftover/dead code

Yarwin · 2024-09-27T09:07:52Z

examples/multiplayer-lan/godot/README.md

+
+
+
+Largely adapted from FinePointCGI's Godot multiplayer tutorial:


why are we adapting youtube tutorial instead of one of godot's demo projects? https://github.com/godotengine/godot-demo-projects/tree/master/networking

Yarwin · 2024-09-27T09:09:20Z

examples/multiplayer-lan/rust/src/bullet.rs

+            ProjectSettings::singleton()
+                .get_setting("physics/2d/default_gravity".into())
+                .try_to::<f64>(),
+            "default setting in Godot",


…what does it error message do? What does it inform user about? "default setting in godot" informing about… not being able to cast given setting to float?

Yarwin · 2024-09-27T09:10:47Z

examples/multiplayer-lan/rust/src/bullet.rs

+    fn physics_process(&mut self, delta: f64) {
+        // delete bullet once LIFETIME seconds have passed
+        self.time_left -= delta;
+        if self.time_left <= 0.0 {


I would rather use scene tree timers or at least SystemTime

Yarwin · 2024-09-27T09:12:01Z

examples/multiplayer-lan/rust/src/bullet.rs

+        }
+        // have bullet fall down while flying
+        if !self.base().is_on_floor() {
+            self.base_mut().get_velocity().x += (self.gravity * 1. * delta) as f32;


get velocity returns Vector2 not &mut Vector2… https://godot-rust.github.io/docs/gdext/master/godot/classes/struct.CharacterBody2D.html#method.get_velocity. Have you ran this example?

removed gravity since it seems unnecessary anyways

Yarwin · 2024-09-27T09:14:04Z

examples/multiplayer-lan/rust/src/multiplayer_controller.rs

+use crate::NetworkId;
+
+const LOCALHOST: &str = "127.0.0.1";
+const PORT: i32 = 8910;


stupid question, but shouldn't it be unsigned int 32b?

Port numbers are usually a u16, e.g. std::net::SocketAddr::new. In Godot it's passed as a string, though. Maybe it'd be nice if we changed that string for a SocketAddr at one point.

Yarwin · 2024-09-27T09:19:07Z

CI/CD to run this example (same as we do with dodge the creeps) would be cool too

I'll build against this example and check it later

fpdotmonkey · 2024-09-27T10:57:28Z

examples/multiplayer-lan/godot/mulCBE9.tmp

@@ -0,0 +1,57 @@
+[gd_scene load_steps=2 format=3 uid="uid://btw6ethmr2246"]


Is this tmp file necessary to check in?

…_PEER_SERVER

…up that work

ValorZard · 2024-09-28T05:30:33Z

Stopping here for now.

I took some advice from the server, and decided to start from scratch and port the multiplayer bomber example instead. However, I ran into the same problem I had when I was working on v1 of this example: namely, the signal/callback api.

So, my current plan is to wait until a later version of gdext when that is more user-friendly to continue with this PR. If anyone still wants to see how using multiplayer with gdext would work, I would advice to look at this commit: 043db66
^ this version of the code ALMOST works, which might be good enough for most people to then go one and figure it out on their own.

Good luck to anyone who tries to follow in my footsteps, here be dragons!

ValorZard · 2024-10-05T21:55:03Z

Closing this PR in favor of #910, since it hews much closer to the official godot demo multiplayer project.

ValorZard added 11 commits September 23, 2024 13:50

start replacing gdscript classes with rust classes

e3d63b7

replicated most of the gameplay from the gdscript side

3e8e3fa

replace gdscript version of player with rust

96821ba

commiting to save progress, but theres some weird bugs cropping up no…

2931157

…w. Hoping that converted the rest to Rust will fix it

redid scene manager, but still getting error regarding player desync

9eb685c

fix networking again, did some refactors

d3ab6b6

converted everything, now time to debug all this

b814869

refactor a bit while trying to hunt down bug

d14981c

fixed connection bug, but now we have bigger problems

33b7080

it works now i guess

6098b09

fixed edge cases with making game wait

30258c4

Bromeon marked this pull request as draft September 24, 2024 07:21

attempt to turn this into an actual game, but im tired

be54093

ValorZard marked this pull request as ready for review September 24, 2024 08:36

Bromeon added feature Adds functionality to the library c: examples Code specific to examples changed (not just follow-up from API updates) labels Sep 24, 2024

ValorZard added 3 commits September 24, 2024 09:41

revert accidental changes to dodge the creeps

e1f74f9

remove unnecessary GDScript and scenes

0d0cc6e

remove game_manager and just pass around player_database instead

71bab84

ValorZard added 2 commits September 24, 2024 12:38

remove binaries that accidentally got generated inside repo

58c250f

remove assets and replace them with dodge the creep player sprite for…

e6e7210

… now

ValorZard added 5 commits September 24, 2024 13:06

make all instances of NetworkId called network_id for sanity sake + a…

2e69a8a

…dd callback for hitting bullet on player

made server in charge of starting the game

abc1612

did some refactoring, still can't get rid of inconsistent connection bug

2f9098b

no more weird sync errors! but now the players have dissapeared

57ea430

add more debugging tools

2e67f77

ValorZard added 3 commits September 25, 2024 13:15

add more comments, and add callback on death

f67e73b

add address bar for custom address + added basic README

9cd0859

fix ci

1f0dd45

Yarwin reviewed Sep 27, 2024

View reviewed changes

Yarwin suggested changes Sep 27, 2024

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Yarwin reviewed Sep 27, 2024

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fpdotmonkey reviewed Sep 27, 2024

View reviewed changes

ValorZard added 3 commits September 27, 2024 11:23

address review comments

f89291e

fix formatting besides one weird cliipy error

4116339

Replace every instance of magic number 1 with MultiplayerPeer::TARGET…

043db66

…_PEER_SERVER

Bromeon marked this pull request as draft September 27, 2024 18:33

ValorZard added 2 commits September 27, 2024 19:57

restarting from scratch, look at previous commit if you want to pick …

9679781

…up that work

this is where i stop

a1d7b30

ValorZard closed this Oct 5, 2024

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[WIP] Add Multiplayer Example #905

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		Largely adapted from FinePointCGI's Godot multiplayer tutorial:

		@@ -0,0 +1,57 @@
		[gd_scene load_steps=2 format=3 uid="uid://btw6ethmr2246"]

[WIP] Add Multiplayer Example #905

[WIP] Add Multiplayer Example #905

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