multiplayer

[fluid summit]

still looks really neat

[glass orchid]

So if an actor is not net relevant i cant get the distance between the actor and my character, right?

since their location is never updated

[fluid summit]

if you are on the server side, yes. because both exist.
If you are on your client, you may be able to get the location if the proxy actor already spawned before (in this case you will have an outdated location for that proxy actor)
if the proxy has never been spawned, the client doesn't know about it.

[amber raft]

Is there a way to play with two player controllers on the same machine?

So that when I run any instance of the application it creates a new player controller for that instance?

[glass orchid]

I want to implement a system where ambient music plays once actorB is within x meters of my character. So im guessing i cant disable relevancy in this case and i need to find a workaround for making actorB invisible

[dark edge]

More than that, they don't exist

[glass orchid]

yeah, so disabling relevancy is not the solution here

[fluid summit]

you can enable it by distance if you are worried about performance

[glass orchid]

im not worried about performance (yet). i just thought disabling relevancy was a good way of making an actor invisible to specific clients

[dark edge]

Just hide the mesh

[fluid summit]

i don't know much about it, but this may be a good case of environmental ques maybe? not sure

[glass orchid]

problem is that i want to be visible to some clients and invisible to others.

[fluid summit]

you can specify more complex conditions for replication

[dark edge]

What's the common thing between the clients. Team, what?

[glass orchid]

yeah, team would be a good way to put it

thematically its about entering a mirror world, which mechanically just hides your character from everyone outside of the mirror world and applies some post process effects

[dark edge]

If you want to trust a client call me you can just have it locally not be visible if the team doesn't match the local team. If you don't want to trust a client, you can just replicate some variable on the character to play the sound floatCloseness

[glass orchid]

ideally i wouldnt trust clients, since in the end it's a pvp game, and those are very vulnerable to cheating

How would i go about setting up such a team system?

[dark edge]

K so just use relevency and tell the client how close they are

[glass orchid]

and how do i tell the client only how close they are?

[dark edge]

The same way you do anything. Either an RPC or a replicated variable.

You can easily have a variable on your Pawn, call it distance to nearest invisible thingy, and then have the server be set in that. The server tells a client how close they are. The client doesn't figure it out by checking their location and the things location, cuz then they know the things location and can cheat and just go there

[glass orchid]

So the distance variable is set by the server on the player character. That makes sense yeah.

Im guessing this would be done from the gamestate?

[lean surge]

Some of the valorising devs actually made a blog on something very similar they did. It’s called fog of war and the aim is to minimise the effect of wallhacks

https://technology.riotgames.com/news/demolishing-wallhacks-valorants-fog-war

I mean this is mostly location based whether a player should be “visible to another” but you might find it interesting

[glass orchid]

This is a very interesting read, thanks 😄

[hollow belfry]

X from the bp channel:
i'm running into an issue with client to server messages.
i want make an ingame terminal that can control a remote vehicle thats linked with it. should i make an ownership class that controls both from the top down? right now im trying to send messages between them via linked objects and it fails client side.
sorry if this is the wrong channel!

[fresh geode]

I'll keep it

[fathom aspen]

Keep this one instead @fresh geode

[obsidian cargo]

High level question: How do you have clients pass custom "character data" to the server when joining? I'm thinking preferences data such as name, character hair color, etc.

Or more particularly, I need clients to indicate if they are VR or non-VR when they join so the correct character can be spawned for them

[fathom aspen]

Do you mean data they had from previous level?

[obsidian cargo]

That too, but also on first connection

I've been looking at a few places on the connection flow, and I don't see where I can send custom data

I'm sure there has to be something I'm overlooking

[graceful flame]

EventOnPostLogin

[fathom aspen]

There are many ways...

That's the good news

The bad news is that you're going to have a hard time picking what works best for you

[obsidian cargo]

Yeah I know with a dedicated server you'd want to have user accounts, etc. But for now I just want a simple and dirty LAN approach where I trust the client

Just building some quick PoC stuff to test viability of VR and non-vr playing together

[fathom aspen]

One thing you can consider is the OptionsString. You pass it to the server when you travel

Even on first connection

[obsidian cargo]

So you'd string encode the data in the options string?

[fathom aspen]

Correct

You have a bunch of params/options

Each can has its value

[obsidian cargo]

I've read about the options string before but I'm having trouble remembering where in the connection flow it is

[fathom aspen]

You parse it when the player joins

See InitNewPlayer for reference

In GameModeBase

[obsidian cargo]

Oh looks like there is a good wiki article related to that https://michaeljcole.github.io/wiki.unrealengine.com/Passing_Arguments_To_Server_During_Connection/

[fathom aspen]

Well the OptionsString you have in GameMode is saved only for first connection. So don't use it xD

See the login functions

PreLogin

Login

[obsidian cargo]

Oh good to know

[fathom aspen]

The URL param there is what you're looking for

InitNewPlayer

For example parses the PlayerName

[fathom aspen]

Yeah something like this. It's funny that I'm writing on it now, and had the whole day researching it and testing

It's a quite handy tool, really underrated

[obsidian cargo]

I was hoping there was a diagram / document about this flow that I missed somewhere. Cedric's guide is great, but I still feel a little fuzzy on some of the details

[fathom aspen]

You can also have some sort of a database service linked and have something similar where you parse data on player login

[obsidian cargo]

Of course, this would be the production way I would want to do it. To provide a correct level of security and persistence

For now I'm building out a PoC as quickly as possible so I can try to win publisher funding on the project

[fathom aspen]

Yeah that one is awesome, but lacks some juicy stuff :(

We should pay Cedric to write lol

[obsidian cargo]

🤔 Yeah that might work

[fathom aspen]

Yeah that's how I would handle it at some point

[obsidian cargo]

I've spent the last 8 months building a custom Chaos Destruction alternative that is VR friendly and fully replicated. But I've done most my testing in PIE up to this point

[quasi tide]

You dare insult the networking bible? The unreal gods are disappointed

[obsidian cargo]

Now I want to scale up to a more direct LAN test with VR / non VR players

[fathom aspen]

Pardon me my lords 🙏🏼🤣

[fathom aspen]

Oh no. I had some PIE gotchas the other day. Never... never test in PIE, unless you're really lazy launching standalone

[obsidian cargo]

I set my connection speeds and packet loss percentages to ludicrous numbers and found the CMC replication falls apart long before my custom destruction system does

[obsidian cargo]

Because single process, or something else?

[fathom aspen]

Yeah that's it. It really doesn't reflect how your game going to function in realtime

[obsidian cargo]

Yeah I have some concerns that single process muddles my results

[fathom aspen]

Also some of the things just don't work or crash. Take for example a seamless travel

[obsidian cargo]

In theory I should be safe regardless of packet ordering. Holy hell was packet ordering difficult to consider when dealing with alternating break / repair events

[obsidian cargo]

This one scares me. I have not yet done any map travel

It should in theory be pretty simple, but I'm vague on the details

[fathom aspen]

Correct. Every time I've seen some peep wanna go around this, it didn't end quite well

[fathom aspen]

It's after you read my next post

[quasi tide]

Apparently they're working on getting server travel to work in PIE

[obsidian cargo]

Fast array and event ids came in to save the day. I had to bundle a lot of data together and use a GAS like approach to keep the actual transmitted data to a minimum

[fathom aspen]

Hopefully @quasi tide doesn't find a lot of bugs in there xD

[obsidian cargo]

Fast Array has some quirks. I NEVER "update" any of my elements, but sometimes I get a replicated update

[fathom aspen]

That's something I was so happy about. Rapid testing is cool tbh

[obsidian cargo]

I went with a "read only" data approach where entries are only ever created or deleted, but never modified.

Yet I rarely get the update rep event on clients. I don't know if it's something to do with PIE, or just a quirk with Fast Array in general

Right now it's a small amount and I just ignore it

[fathom aspen]

Sick, haven't faced that. Still it's one of the best, if not best tool in mp

[obsidian cargo]

Tell me about it I ❤️ FastArray

Made things so much easier for a neophyte like myself

Prediction Keys in GAS are pretty sick too

I made a simplified version for my own prediction. Really cool techinique.

In my case the prediction is visual only, so I didn't need to support roll back of any form.

[fathom aspen]

Yeah GAS is inevitable too. Has to get into it asap!!!

It's like every system out there has some GAS in it

[pallid mesa]

depends what you do™️

[fathom aspen]

Yeah it's really a depends™️

Though when it comes to travels it's like never

Even hard travels

I mean I found that OpenLevel won't work if Absoulte was turned off in PIE. Though it works fine in standalone

[pallid mesa]

yeah traveling is out of the question in pie

i wish we'd get something working

[fathom aspen]

Has to so with single process thingy prolly

[fathom aspen]

Maybe after my post we can get them to do something about it ^^

[pallid mesa]

btw sharing is caring 😁

[limber gyro]

hey guys, does any one have a code snipet on how to pass an int as an option to a server?

[solar stirrup]

Define pass

[fathom aspen]

#blueprint message

[limber gyro]

i forgot to say it was in c++

my bad

[fathom aspen]

Same thing. Use HandleOpenCommand

HandleServerTravelCommand

Whatever function works for you

And pass that URL like it's passed in the link I sent you

You have multiple options and they are separated with ? sign

You parse it when you login

[limber gyro]

ok my question might be a terribly articulated, what i meant was that i need to get the value in c++ after the server is open so that i can pass it onto a variable

[fathom aspen]

My answer still stands

See InitNewPlayer

Inside GameModeBase

They parse the PlayerName in there

[limber gyro]

im getting those values in the initGameState

im looking for something like this

    {
        UE_LOG(LogTemp, Warning, TEXT("Restart match setted"));
        restartMatch = true;
    }

[fathom aspen]

You can parse ints too

[limber gyro]

yes i just dont know the function

thats what i am asking

[fathom aspen]

That seems too much low level. It's already there

Again go to the function I suggested

You'll get it once you look in there

[fathom aspen]

^

[limber gyro]

u mean HandleOpenCommand?

[fathom aspen]

That's the function that opens a level. Do you want to be able to pass the int on travel?

Or occasionally?

[limber gyro]

on travel

[fathom aspen]

Ok then look at the travel functions

There's a plenty

[fathom aspen]

That's one of them

https://docs.unrealengine.com/4.27/en-US/InteractiveExperiences/Networking/Travelling/

[obsidian cargo]

Just got back from lunch. Guess I should put together a blog to share this kind of stuff in

[pallid mesa]

😄

[obsidian cargo]

Recommendations for a blog? I have a domain for my company. It's on my list to spin up a website soonish.

[fathom aspen]

I find GitHub Pages amazing ^^

[fathom aspen]

What do you think github.io boy?

[pallid mesa]

don't bully Wiz

[obsidian cargo]

Only 129 lines in header and 44 in cpp, should I just post it here?

Funny part is most of it is usage notes

LOL

[fathom aspen]

Feel free

[obsidian cargo]

Oh looks like discord thinks it is too long

I'll look into a blog in a few days

The key core idea is really simple though. You just need this in your structure: ```cpp
bool bIsOnServer = false;
/**

• On the Server, this uniquely identifies the network connection this was serialized on/from.
• On the Client, will always be zero.
  */
  UPTRINT ConnectionKey = 0;```

And this in your net serialize: ```cpp
bool FSimplifiedPrectionKey::NetSerialize(FArchive& ar, class UPackageMap* map, bool& bOutSuccess)
{
// Only net serialized bit is if this is the connection for the client of interest. (most are not)
bool bIsSet = false;
if (ar.IsSaving())
{

     // The ConnectionKey is only valid on the server if this serialize is going to or coming from the client it was created for.
     // It is never valid on the client, but doesn't matter as client operates exclusively on bIsSet
    bIsSet = ((UPTRINT)map == ConnectionKey);
}
ar.SerializeBits(&bIsSet, 1);

if (ar.IsLoading())
{
    // Determine if this is on the server.
    UPackageMapClient* mapClient = Cast<UPackageMapClient>(map);
    if (mapClient)
    {
        bIsOnServer = mapClient->GetConnection()->Driver->IsServer();
    }

    if (bIsSet || bIsOnServer)
    {
        // Will get here if on a client and the server indicates the data around this serialize were predicted
        // OR will get here if on the server receiving details from a client that the client predicted
        ConnectionKey = (UPTRINT)map;
    }
    else
    {
        ConnectionKey = 0;
    }
}

bOutSuccess = true;
return true;

}

Oh and you also need this in the header, but it's pretty simple: ```cpp
/**
* If true, we know the RPC or rep that sent this key was predicted by the client.
*/
bool WasPredictedByClient() const
{
return IsSet() && !IsOnServer();
}

/**
* On Server, if true and a proper ConnectionKey is set, the Server will notify the Client that replicated Cues were previously predicted and don't need to be played again.
* On the Client in Break and Repair calls, this tells the client it can avoid calling the Server RPCs because the server is already running the logic.
*/
bool IsSet() const { return ConnectionKey != 0; }
/**
* Returns true if this key was told it was created on the server.
*/
bool IsOnServer() const { return bIsOnServer; }```

The reference to "Break and Repair calls" comes from my destruction system. They are essentially calls made interchangeably on server / client that "magically" cause the logic to end up on the server because they utilize an internal Server RPC call that just calls back into the Break / Repair call.

IE: void Break(/stuff/, predictionKey); is called on both client and server, and inside is if (IsClient() && !predictionKey.IsSet()) { Server_Break(/stuff/, predictionKey); }

void Server_Break(/stuff/, predictionKey) { Break(/stuff/, predictionKey); }

There's additional validation details, but not related to the prediction key here.

@pallid mesa ^ Feel free to use. I can share additional details if needed.

Ultimately, this is just a regurgitation of the prediction key in GAS with a small amount of added documentation.

[unkempt tiger]

Is anyone else experiencing horrible performance when playing as several clients in PIE on UE5?

[obsidian cargo]

As in more so than UE4?

I've observed really odd issues with timing with clients with PIE in 4. As in timers have finished 6 or 7 frames too soon or too late

[unkempt tiger]

It feels like it's gotten worse

But yeah, in UE4 it was also bad, especially after upgrading to 4.27 if I recall correctly

[obsidian cargo]

Cries in 4.27

[unkempt tiger]

Are you using Wwise @obsidian cargo ?

[obsidian cargo]

Absolutely not

I've used it in the past and won't touch it if I don't have to

[unkempt tiger]

What did you dislike about it?

Welp maybe not directly #multiplayer related

[obsidian cargo]

I was using it at a smaller company where it was way overkill, but the short version is it was a PITA to get asset packs for DLC in Unity working.

Maybe the Wwise UE integration is better 🤷

[unkempt tiger]

Oh I can imagine, I asked because I thought it was having trouble handling different audio devices for each client, but perhaps that's not the case

[rancid monolith]

I'm trying to equip a weapon to player characters using a c++ function called during BeginPlay, but for some reason the weapon class (assigned through blueprint) is null, but only for clients. It works when run standalone or as listen server, but not for connecting clients.

Should I be calling the function elsewhere, in case I need to wait for the value to initialize or something?

[twin juniper]

Guys a help here for me, I installed an unreal engine 5, I put the Sessions plugins for the guys to use with a steam and I'm stuck for 8 h trying to fix a package error by the plugins.

no joke
https://forums.unrealengine.com/t/engine-is-unable-to-access-appdata/624025

[valid bough]

Hey, im playing on a listen server testing out my game. How do I get all the players in the listen server? I put the player count to 2 and im only getting 1 print back which is my computer. How can I get the actual pawns / players in game? I understand why its printing my pc because im the only pc in the game but I'm playing with the player count to 2 i need both players locally on this PC currently playing

Should I just get world , get all actors of class and point to the controllers its using?

[lusty yarrow]

Hey I got a dedicated server running on aws gamelift, whenever I try to connect to it (no gamelift features usage yet) with IP:PORT in the Open Level node, I get this error LogOnlineSession: Warning: OSS: No game present to join for session (GameSession)

I thought the dedicated server is supposed to create a session when it gets a connection?

[crystal crag]

How are you supposed to know which friend is tied to the presence structure?

[2022.08.08-23.33.27:532][ 85]LogRaevinParty: Warning: FOnlineUserPresence {Online: 1 Playing: 1 ThisGame: 1 Joinable: 0 VoiceSupport: 0 SessionId: NULL Status: FOnlineUserPresenceStatus {State: Online, Status: , Properties: }

What the hell am I supposed to do with that

That is the most worthless event ever, in the history of events

OSS: Hey! Hey now! There is someone that has updated their presence and is playing the same game you are playing!
Game code: Ok great! I am so glad to hear that. Who is it? so can you tell me who they are?
OSS: Oh it's... it's.... well I don't know. I can just tell you that someone is online playing the same game you are.
Game code: Oh... well I am so glad that someone on the planet is playing the same game I am playing. It sure would be great to know who so I can invite them into the game.

[weak osprey]

So, I've found a variety of projects you can purchase that enable multiplayer over lan, but none that are first person over epic services and/or steam; has anyone found a project like that available for purchase?

I don't want to code it myself, I want to code on top of it. Sorry in blueprints, all this.

[novel bison]

qq: if a ballistics plugin needs me to run animations on the server is that going to cause performance problems? i dont think the animation itself would have to be synced, but just assuming that it runs if the same overlay state is active on the server

[fathom aspen]

Inside GameState there's PlayerArray. It's an array of all PlayerStates. You can get its size. Also to get the Controller call GetOwner on PlayerState (array element)

[winged badger]

this is also one of the very rare uses where GetPlayerCharacter[Index] is acceptable

GetGameMode->GetNumPlayers->For (0 to NumPlayers - 1) GetPlayerCharacter[Index]

[fathom aspen]

Yeah I was amazed the other day that these functions works on server for indices bigger than 0

Or maybe GetPawn on that PlayerState array element

Sorry to necro this, though I didn't think of this at the time. How do you get a refernce to the deactivated PS inside OnDeactivated? Do you cache the one Duplicate creates?

[winged badger]

It has a function thats called like that

So its this

That is actually a pretty good way to iterate all characters or controllers from bp

On server

[fathom aspen]

Sorry I didn't follow-up. Are you referring to Duplicate (my question)?

[winged badger]

void ARTS_PlayerState::OnDeactivated()

which is an engine function override

[fathom aspen]

Correct. It has no reference to the inactive duplicated PS. It destroys the old one by default

void APlayerState::OnDeactivated()
{
    // By default we duplicate the inactive player state and destroy the old one
    Destroy();
}

I was asking how you get the reference to the inactive duplicate PS 😄

I'm afraid that overriding Duplicate and caching the one created there has side effects

The other option would be to traverse the InactivePlayerArray here and finding it based on UniqueId (before old PS is destroyed at that line) for example, but that seems an overkill 😦

[winged badger]

ask me next week when i have more time to dig through code i only vaguely remember writing

this week DLC going out

we might had not duplicated and destroyed the PS, i don't remember now

[fathom aspen]

Thank you and no worries. Also good luck on that too!

[coral wing]

How do you name your multiplayer session for people searching.

[ocean vessel]

Hello, I have a specific problem

Current floor in Character Movement Component doesn't return actor on Simulated proxies on Clients, but only on a spline mesh i've created. I guess there's something i should turn on in the collision, but i have no idea what.

[grand mica]

@fathom aspen another question for you.
I am trying to print logs on client's screen from AIController.
Since you told AIController logic happens in the server so I tried to print the logs with client rpc, didn't work. Then I tried to call the server function and then call client rpc to print the logs

nothing worked tho

how should I approach this?

[thin stratus]

If you try that then you didn't understand Ownership

You can't run ClientRPC on something that isn't owned by a Client.
And that AIController, ontop, doesn't even exist on the Client.

[grand mica]

Gotchya, but since AIController exist on the server then by calling client rpc on it's character would have printed the logs?

I tried to print it from the character too.

[thin stratus]

Is that Character owned by a Client?

Answer: No

So no, it won't work there either

AI is Server Auth

[grand mica]

How should I approach this then?

[thin stratus]

What are you trying to do?

[grand mica]

want to print the Bots' tasks on client's screen to know what they are trying to do

[thin stratus]

Is that for Debugging?

[grand mica]

yes

[thin stratus]

If that's only for debugging and will be removed again, use GetAllActorsOfClass with the PlayerController as Class

And call the RPC on that.

[grand mica]

I was actually printing the logs on specific events for specific duration. With this i guess it has to be printed on tick to track what's happening

[thin stratus]

Depending on what it is, you can also simply replicate in through the Character

And let Tick print it locally

Just not via Client RPCs

[grand mica]

it will print if I call a delegate on the playercontroller when the event gets triggered?

player controller will have client auth I guess and calling a delegate from server to client might work?

[grand mica]

uhm, I can replicate the task and it should print the values but along with it i wanted to print the name of the bot as well. Uhmmmmmmmmm

[fathom aspen]

No delegates are local

Only way to go from server to client is either replication or RPCs

Attach a 3d widget to your AI pawn and print w/e you want to it

Since AI pawns replicate you should see what they are trying to do

[gilded merlin]

Hi. My case is that I have 2 players, one is listen server, second one is player.

I use repnotify to close or open doors.

Repnotify is being called on the server, and the door mesh location is being updated, however, mesh collision isn't updated, until I get a little bit closer.
Any ideas why would it behave like that, any solution?

(So when I want to go trough the doors on client, i cannot do that because server thinks there's collision and blocks the player)

(I move doors using animations)

[thin stratus]

Is that a SkeletalMesh?

[gilded merlin]

Yes

[thin stratus]

Go into the SkeletalMeshComponent of your Door

And check for the Bone Updates

It should always update, not only when rendered

[gilded merlin]

Is that what you mean?

[thin stratus]

Think so yeah

There is an option to always tick everything or so

[gilded merlin]

Doesn't seem to work 😦

[thin stratus]

Are you actively Playing a Montage when opening the door or just setting the position?

[gilded merlin]

Setting the variable which translates to anim percent

[thin stratus]

Does it work if the Server stands directly next to it?

[gilded merlin]

yes

[thin stratus]

So if you are further away, you can still see the door opening on the Server, but hte Client isnt able to go through?

[gilded merlin]

yes

I can see that the doors are open, both on the server and on the client

But I can't go through them with client until I get closer with the server

I even debugged it, and can see which specific skeletal mesh is blocking me, even thou on server it looks like it's open

[thin stratus]

What happens if you move the whole mesh component aside in your OnRep?

(trying to see if it's animation related)

[gilded merlin]

It works then

So it seems to be animation related

[thin stratus]

Hm, then it's something with the animation :<

Not sure right now, sorry

[gilded merlin]

sure, np. Thanks for trying! I'm a little bit closer now anyways

I'll let you know what it was when I fix that

[grand mica]

3d widget is a good idea

[worn wagon]

Question about replication. Say I set a couple of replicated variables one after another serverside, are they guaranteed to arrive in any particular order?

[fathom aspen]

Nope

[worn wagon]

didn't think so

thanks

Syncing variables with RPCs seems much easier to work with

[chrome bay]

It's not because late join and relevancy breaks it

Persistent properties should always be replicated vars

[worn wagon]

Yes this is what im having to deal with right now

It's irritating

I need some of the functionality of both

[chrome bay]

The way to deal with it is to mark the vars as replicated, everything else should work automatically. If you use RPC's then state will be lost

If you want properties to replicate together, put them in a struct and define a custom NetSerialize() method for it - but note that you lose the delta-replication that way

[worn wagon]

For example though, for firing a weapon I was queuing up weapon shots to deal with variable latency. If the client shoots an automatic weapon with a ping of 100ms, then the next shot the ping is 90ms, the server won't be ready to fire again because of the fire rate, so it needs to be queued up and fired as soon as it's allowed. But this meant the replicated ammo was being changed on the server and replicated late causing the client's ammo to jump sharply.

So I set it to replicate conditionally as InitialOnly and do the rest with rpcs

[chrome bay]

It won't work - and it won't make a difference anyway because the RPC will arrive just as late as the property

[worn wagon]

Wdym

[chrome bay]

the latency is the same regardless of whether you use a replicated property or an RPC

[worn wagon]

Oh I only update the ammo on a reload

[chrome bay]

An RPC can actually be worse, because when they are reliable they delay all other reliable RPC's to preserve execution order

[worn wagon]

I know the latency is the same

So the client ammo is independent outside of reloads

But it should always be the same outside of the client cheating, even so it wouldn't matter it's still validated on the server

[chrome bay]

The other approach ofc is a prediction system. The ability system has this built in as a general concept, but you can also roll your own

But the real problem is you will have trouble synchronising the true state of the weapon if network relevancy changes or when a client joins late, because the server will have no idea what properties changed for each client.

[worn wagon]

Queuing up the inputs seems to work pretty well

At least for my purposes

I have a question, since you seem pretty experienced. I'm having issues with the "first function" to be called when a pawn is created or restarted. Sometimes the beginplay function is called first, sometimes the restart function gets called first. It's annoying. Also the listen server host has its own set of issues with running all of that shit before the pawn gets possessed. Is there somewhere you can run code after the pawn is created AND after it has been possessed?

Something that is guaranteed to run before everything else

It sounds like it should be obvious

[chrome bay]

There isn't really, possession is determined by the controller - and since it's a different actor it replicates independently of the pawn, so it's fairly random whether or not the pawn will be fully possessed when BeginPlay() etc. is called.

But you can workaround it by overriding things like the OnRep callback functions

Similarly whether BeginPlay() is to be called is determined by the GameState, which is another independent replicated actor - so there are race conditions between three different actors for something like that. These are mainly why the OnRep functionality exists, to be able to handle initialization/changes etc. when properties are updated from replication.

[quasi tide]

I have a question, since you seem pretty experienced.
I'd hope Jambax is pretty experienced. Job title would be awkward otherwise 😅

[fluid summit]

@dark edge Hi! i was thinking on how to make this "packages" of similarity with the wave function collapse approach.

i'm thinking on use the normal weights that they already have for the chances of spawn and also add a new condition like "Multiplied chance of same cell type near" and a flag for it.
So if i want to, there's X more chance of a cell of the same type spawning around it.
What do you think? did you have something similar on your setup?
p.d.: posting it here and not dm because maybe it's usefull for someone

[chrome bay]

@worn wagon Generally you can get around race initialization issues doing something like this:

{
    Super::BeginPlay();
    
    TryInitiailize();
}

virtual void OnRep_Controller()
{
    Super::OnRep_Controller();

    TryInitialize();
}

virtual void OnPossessed()
{
    Super::OnPossessed();

    TryInitialize();
}

void TryInitialize()
{
    if (HasBegunPlay() && GetController())
    {
        // Do init
    }
}

Psuedo-code but you get the gist..

[fading python]

@thin stratus Hi, do you setup and manage UE5 servers?

[worn wagon]

Thank you very much 🙂

The initialisation issues have been annoying me for a while now

so OnRep_Controller is basically the clientside version of OnPossessed?

I wonder if it would be called at any other times

[chrome bay]

The OnRep's are just called whenever the replicated property is changed, so it could be valid, or it could be null

[twin juniper]

Hey, any good tutorials to make a UE5 game server
I have source access and did pull it off in UE4 but that was ages ago

[static sable]

hi, anyone has any good doc on "fog of war in RTS" - obviously I don't want to replicate any info if unit is in the fog... etc...

[fathom aspen]

This was sent yesterday: #multiplayer message

Didn't check it yet

[limber gyro]

hey guys, this works on the editor but not when i package the game, any ideas?

it complains of invalid options

nvm i misspeled a letter

if i want to spawn UI only on the client what would be the ideal node for the "if" check?

[graceful flame]

UI is client side only anyways, not sure which if you're talking about, the screenshot is tiny.

[limber gyro]

so if i do like a "add to view port" it wont run on the server by default?

[graceful flame]

Are you using listen server?

or dedicated

actually doesn't matter, its client only yeah, mouse over the Add To ViewPort node and it tells you

[limber gyro]

my idea was to use a check for performance reasons but it seems that its not needed then

im acualy using both server types

the cast that i am doing will still run in the server i assume but a cast only shouldnt be an issue

[graceful flame]

I don't see any cast in your screenshot

[limber gyro]

that screen was referent to something else

this is was what i was refering to after

it had a "if" at the beggining

so since those nodes are client side only does that mean that the execution stops at the client side nodes in the server or the next nodes still run?

[graceful flame]

i dunno, just step through your code with breakpoints to find out

[dark edge]

I'm not sure if anyone's done WFC on hexes but I'm sure it's doable. You could also consider a markov chain approach. What's your current map gen?

[graceful flame]

If the server reaches "Create Hud widget" it stops there because that's a client only node.

[fathom aspen]

Those functions are cosmetic meaning they don't run on dedicated servers, or shouldn't be

They would get you errors in such case

Widgets in general are owned/assigned to local controllers

So they can still be server sided in case of a listen server player

[fluid summit]

1. WFC
2. Zones mark for biomes
3. More fine specialization on each cell within those biomes

wtf on hexas is quite similar, i'm just trying to think of the better way to do those "clusters" of same type cells

[fathom aspen]

This is a good if:

[fathom aspen]

Frankly they execute (dedicated servers) what comes afterwards, though I recall that once errors start popping (error accessed none...)in a BP node they don't execute what comes afterwards, but that's incorrect 😦

[graceful flame]

Well it switches to whatever client stuff has to be processed next then back to server for the other player... etc right?

You can test this by setting a breakpoint and leaving the debugger set to default instead of a specific target and watch as the process happens.

[fathom aspen]

Yeah it executes on whatever instance calls that flow, even if one of them fails it

[rancid monolith]

On my character actor class, I have a property that I assigned in the character's blueprint, and for some reason it's just a null reference for characters running on client games.
It works properly for all characters on the server when playing as a listen server, and when playing standalone.
Any idea what might be the cause of that?

[sinful tree]

Is it a replicated property?

[rancid monolith]

Yeah, but I probably messed something up setting it up

[sinful tree]

What type of reference is it?

[rancid monolith]

UClass

UPROPERTY(EditDefaultsOnly, Replicated)
UClass* FPAnimInstance;

[sinful tree]

Do you have the property defined in the GetLifetimeReplicatedProps function?

[rancid monolith]

I have:
void AWeaponBase::GetLifetimeReplicatedProps(TArray< FLifetimeProperty >& OutLifetimeProps) const
{
Super::GetLifetimeReplicatedProps(OutLifetimeProps);
DOREPLIFETIME(AWeaponBase, FPAnimInstance);
}

[sinful tree]

Is AWeaponBase marked to replicate?

[rancid monolith]

in the derived blueprint class I made, yeah it is

[still coral]

Question: is setting the Velocity manually client prediction friendly?
I'm doing this on the client for prediction but also doing the same on the server, and I'm getting hitches whenever this happens 😐

[light iron]

Does anyone have a resource for setting up a team, round based single elimination game mode? Using Lyra so I have teams set up, but would like some guidance as to how to craft this alongside their toolset.

[winged badger]

depends on the order

if predicted, and server modifies speed/velocity first, you get corrections

if autonomous proxy modifies it first and RPCs it to server, then corrections are minimal, if any

[shell forum]

How would one go about persisting something like an array of playerstates through seamless travel?

Aside from using GameInstance.

[worn wagon]

Override CopyProperties in playerstate

https://docs.unrealengine.com/5.0/en-US/API/Runtime/Engine/GameFramework/APlayerState/CopyProperties/

It thought it was in gamestate too but I can't find it

Also, does anyone know if OnRep is called if the value hasn't actually changed? In the case where you update a variable on the client and server around the same time, then the server goes to replicate it. I'm sure I could figure out a test for this but would be easier if someone knew already xD

[sinful tree]

99.9% sure the answer is no. No OnRep called if the value doesn't change.

[worn wagon]

Ok great, that's what I was hoping for

Since I want variables to be replicated but I also need them to be update in a timely manner in some situations via reliable RPCs. If it called on rep after the rpc updated the value on the client it would run the functionality twice which is not what I want.

Seems like it should all work out then

[worn wagon]

Like you said earlier the GameInstance is the place to do it

That's the only thing that will persist across levels

Outside of caveats like the copyproperties function

Also

So in seamless travel the gamemode will be carried over, you can just store stuff there it seems

[celest pulsar]

Hi, i'm trying to build multiplayer game for ios base on listen server, and i'm able to create and join session, but client failed to load shared map after joining. I use OnlineSubsysremNull and Unreal@4.27.2. Is there something i do it wrong. Please any help will be grateful.

https://www.reddit.com/r/unrealengine/comments/wk8tcv/ios_multiplayer_ios_join_session_but_failed_to/

[fathom aspen]

See how it's done in AGameModeBase::GetSeamlessTravelActorList. PlayerArray persists, so you have a point in time where you have the old and new references of PS and you can use a function like CopyProperties

The functionality is already there

[fathom aspen]

It doesn't persist to destination level but to transition. Epic must fix that

[worn wagon]

So I guess you're stuck using gameinstance?

[winged badger]

there is also a funny part where the travel map game mode can fuck up the seamless travel list

[fathom aspen]

Even if you use the GameInstance to persist PlayerStates that are linked to players you're still out of luck. The references are still destroyed

[winged badger]

if not of the same class

[fathom aspen]

Haha yeah

I mean try to override that function and make the GameMode persist to destination level

You would still have to reconnect your players, otherwise they're stuck

[fathom aspen]

It seems like that function "truly persists" actors that are not part of the GameFramework. Otherwise you have to copy stuff over

[winged badger]

i have a mission setup actor

it gets loaded with entire map and random generation config

travels to combat, records notable stuff there

travels back to lobby

in campaign mode that carries information like deployment result victory/retreat/defeat back

and then strategy layer awards are based on that result

and also, as a seamless travel actor

it and all its data is there and ready to be used when functions like InitGameState start to be called

so its great for initialization order too, its just there, no matter how early you try to find it

[fathom aspen]

Wow, cool! The reference truly persists. Though GameMode is the one that spawned it right?

[winged badger]

reference does not

i do need to actually find it from the GameMode

each time i transition a level

[fathom aspen]

You TActorRange it?

[winged badger]

GameMode did spawn it, but that doesn't matter for travel here

yes

[fathom aspen]

I see. So you don't cache a reference but find it, as the reference won't keep up

[worn wagon]

what does this do?

[winged badger]

for (AMyActor* MyActor : TActorRange<AMyActor>(GetWorld())

more elegant syntax for iterating actors of type

[fathom aspen]

Finds an actor (iterates)

Elegancy at its finest

[worn wagon]

Ah i see very nice

[still coral]

The 2nd option is what's happening, but a hitch still happens. It's small/short, but still jarring because the player is going a bit fast 😅

[winged badger]

if its a bit fast

you might want to configure CMC for greater tolerance before correction

[celest pulsar]

Please, i spent three frustrated days to solve this problem, does anyone have some clue to solve this ??

[humble edge]

Dedicated server stucks at this log . Dedicated server of Old version of this Project runs successfully last log (Engine Initialization) while dedicated server of updated version of project dont initialize properly and cant connect to clients. Help how can i fix it ? Anyone who has experienced this and solved it?

[gilded merlin]

It seems that this checkbox was causing this problem.

After I changed to always refresh as you suggested and unchecked this checkbox it seems to be working now 🙂 Thank you very much

[thin stratus]

A nice, glad it helped

[sand holly]

Incredibly rookie question, but do you need to spend money on servers if you want to make an online game with Unreal? Or does Unreal already have servers you can use?

[hoary nova]

I think there are some options as to servers, but i'm guessing they are not free. Check Epic online services, I haven't looked into it myself but I'm guessing it is exactly that - servers.
also unreal supports peer to peer

[fathom aspen]

Unreal doesn't support a true p2p. The most close configuration to that is called listen-server, were stuff has still to go into the server.

[sand holly]

With a listen server everything depends on the host right? So when the host disconnects does the server get shut down? Or is there a way to make another player the host to prevent this from happening?

[fathom aspen]

Yes by default, everyone is disconnected. A while back, someone sent a plugin here were they workaround that. Not sure what they do

[sand holly]

So can't you make another player the new host of the server?

[fathom aspen]

This: #multiplayer message

[sand holly]

Wow exactly what I was looking for. I'll take a look, thanks!

[celest pulsar]

Hi, i have the same "UniqueId: INVALID" problem. Do you solve it finally ??

[opal fox]

anyone know how to communicate with a the Client regarding sending values to the Animation blueprint from a server only place in code? Sending an rpc to owning client doesnt work because the server is the one who owns the creatures im trying to animate.

[unreal plover]

Hey everyone,
So I'm creating a multiplayer game with Steam OSS. So far I'm able to host and join on LAN. But, when creating over Steam OSS, third player is unable to see the hosted server, i.e. not listing in the server browser. Checked server settings and max allowed players. Everything works fine in LAN session but not so much in Steam session. Anyone having any insights on this?

[thin stratus]

Is there a UActorComponent function that guarantees that I can run RPCs from that point on?

Other than BeginPlay

[static flare]

I attach a ChildActor to a ParentActor using SnapIncludingScale, and set the Parent's scale to 0.5. They both scale down to 0.5. And the child's Transform.Scale is 1 (so it's relative to Parent). Nice. This is as expected.

Then I replicate the Parent (and the child) to a client, and there they show up with Parent scaled at 0.5 (correct) and the Child scaled at 0.5 (relative to parent, so 0.25 in world scale). Why?
How does the attached child inherit the scale?

[thin stratus]

Are you scaling the Actor directly?

Cause iirc ActorScale is already replicated

It basically takes the ActorScale and applies it twice then

Which causes your 0.25

[static flare]

So, I'm actually only spawning a ParentActor, with scale 0.5 in its Transform. That code only executes once, and only on the server.
That ParentActor then spawns the ChildActor (during its OnConstruction) and attaches it to itself using SnapToTargetIncludingScale. I store a (replicated) reference to the ChildActor in the ParentActor.

It feels like the ACTOR-instance for the Child is replicating itself with 0.5 scale because that's its RootComponent's world-scale on the server, disregarding the fact that its scale is 1 relative to its RootComponent's ParentComponent (since it's attached). Or.. something. This is hard for me. Could the ChildActor's "ActorReplication" be fighting with the ParentActor's "ComponentReplication"-stuff? Since the ChildActor is a "replicated actor reference" and a replicated component..?
(So no, I never apply any scale on the client-side, and never on the Child)

[mighty barn]

I'm wondering about the best way to set up locomotion to be multiplayer ready, would state machines be the best choice?

[opal fox]

@mighty barn theres no multiplayer regarding state machines

and what do you mean by multiplayer ready?

[mighty barn]

Im hoping to use listen servers and allow players to host their own server by acting as a client for other people to connect to. I was wondering how I should set up everything so that it would be replicated properly

[thin stratus]

Hm okay, I would argue that scaling actors is already a bit of a hazzle

I usually only scale visuals and change collision sizes accordingly, cause I only had issues with Actor Scale and networking

[opal fox]

@mighty barn as far as I know the replication of the animation blueprints its already handled by epic, if youre playing a specific animation based on a specific variable, u just need to make sure the clients and server are synced on the value

so yeah just using the normal state machine is probably the most common solution to your problem

[unreal plover]

How to call a function declared in client game instance from server game mode?

[mighty barn]

Thank you! I just needed some confirmation before spending time on it

[fathom aspen]

From GameMode iterate PlayerControllers or w/e till you find the client you are talking about. Call a client RPC on it and from that client RPC access that client side GameInstance function

[still coral]

This is what I was playing with, but wasn't sure I should do this 😅

[winged badger]

there is tolerance somewhere in editable config

i think its 3 UU by default

but that doesn't work for speeds much larger more then bipedal movement speeds

which is saying, it better be under 1000 if you don't want corrections

[dark edge]

Replicate a variable

[opal fox]

@dark edge yes it seems obvious and when I do that it doesnt replicate the variable down to any clients, im nto sure why

not even multicasting the variable works, this is specific because its being done inside a blackboard task, so im not 100% what that implies

[latent heart]

As long as the object it's on is replicated, it should replicate.

As long as the actor is replicated to every client, a multicast rpc should get sent to every client (from the server) as long as the actor is relevant to that client.

[opal fox]

@latent heart so the AIController is always relevant, and the monster or whatever that is using the controller is replicated and everything else replicates, but this specific BTT_BlueprintTask doesnt replicate its variables 😦

[latent heart]

Controllers are never replicated except to their owning client.

It won't be relevant to any clients.

[opal fox]

Yeah, but the actor that has the controller is replicated

and relevant

[latent heart]

Doesn't mean the controller will be.

[opal fox]

no, but is it the controller that owns the BTTasks ?

[latent heart]

Probably.

[opal fox]

Probably something like that yea

Might need to approach hwo those tasks are used a bit differently

[quasi tide]

I'm pretty sure BT's only run on server anyway. Why would a Task be replicating?

Only the server needs to know anything about it.

[latent heart]

Put any variables you need to replicate on the actor itself

[opal fox]

Yeah but if it has some value in the task, that u wanna get to say the animation blueprints, which wants to be on the client

then that is the issue

@latent heart yes I think that makes more sense anyway

[dark edge]

Anything used by anim bp should live on actor

anim bp doesn't care abuot the brains, it cares about the body

[opal fox]

@dark edge yes it makes sense that the animbp should read variables, thats the idea behind recieving information from its replication

[clear swallow]

Would anyone be able to help me figure out why my replication is not smooth please

It is in C++ and I'm just totally stuck

[opal fox]

@clear swallow maybe check the update frequency of the actor

[clear swallow]

I did

[opal fox]

what about it is that is not smooth?

[clear swallow]

I have to set it to 5 and then use the server to update it

[opal fox]

5 is pretty low for a "smooth" behavior

try putting it to 10

see the difference

[clear swallow]

But when i change the variable on the server it wont update and goes really laggy

Like the rate at which the object spins doesnt change on the server at all

[opal fox]

are u updating it to the server ?

or sending it to the server from client

[clear swallow]

It should be yeah

the variable is replicated

[opal fox]

ok so if its replicated then u should set it on the server

and make sure the whatever function ur running on the server is updating frequently enough for it to be smooth

or alternatively lerp the value

[clear swallow]

I am running the movement in tick

[opal fox]

did u try setting the net update frequency to 10 ?

if i set it to 5 on my enemies they are also choppy

[clear swallow]

I can show you what im trying to do if you want

[opal fox]

sure i can have a quick look

[karmic kite]

having trouble getting replicated actor deleting working, when the item is picked up and dropped once every time after that the actor will not be deleted on the client and only on the server how do I fix this issue any ideas? (video of the issue and the code )

[sinful tree]

If it's a replicated actor, you only need to destroy it while running on the server.
You can only call "Run On Server" RPCs on actors that are owned by the client.
It's also a really bad idea to have an RPC that tells the server to delete an actor as someone could potentially spoof that RPC and feed in whatever actor they want, and the server will destroy it.

So what you should do:
Update your Interface to pass along a reference to the interacting player controller or character based on wherever your interact event is.
Your interact event (key press I'm assuming) does as it does up to the point where you're about to pass to the Interact interface.
Instead of calling the interface, do your "Run On Server" event in your player controller or character, wherever your interact interface currently is. Pass through the reference to the actor that you want to interact with.
In the Run On Server event, call the interface on the actor, passing along a reference to player controller/character - this avoids you from having to use anything like "Get Player Character 0" within the item.
Once you validate that the player is able to pick up the item, proceed with destroying it.

[young kestrel]

Quick and maybe stupid question:

Is it normal to have weapons spawned X times? (for each client + server)
If I have 4 clients and each has 3 weapons would that mean the server has to handle 12+ weapons (which are actors)?

[sand holly]

Does anyone know a good document/article that states the pros and cons of each type of networking? Like p2p, listen server, dedicated server, ...

[sinful tree]

In UE there is no P2P, only listen server and dedicated server.
Listen servers have one player acting as the server of the game. If the host leaves, all players are kicked from the game. It generally takes a bit more processing power to be both the server and playing the game.
Dedicated servers are their own copy of the server running with no player acting as the host. If all players leave the game, the server can still be running.

[sand holly]

But a dedicated server costs money right?

[sinful tree]

No. The concept of a "dedicated server" just indicates an instance of the game running in which no players is also playing on that same copy of the game. That means you could run a dedicated server on your own hardware, or a player could run one on theirs. If you wanted to join your dedicated server, you'd have to run another copy of the game and connect to it.

[sand holly]

Does your PC have to constantly run the game for the dedicated server to be up?

Or how does this work, is it like in the background?..

[sinful tree]

Yes. The server executable must be running in order for players to join that server. It doesn't have to be constantly up, but when it's not up, people can't join it.

[sand holly]

Wait so let's say as a player, from the main menu you can create a server that others can find and join. This server doesn't have to be a listen server?

[sinful tree]

Technically yes - you'd have to set it up so it closes that instance of the game then launches the dedicated server (with whatever settings the player has chosen)

[sand holly]

But still when that player leaves the whole server gets shut down right

[sinful tree]

Only if the player shuts down the dedicated server instance / turns off their computer.

[sand holly]

Hm okay, so is there a way to have this system of creating and joining servers without depending on the host?

[sinful tree]

That would mean you would have to manage your own dedicated servers instances like an MMO.

At that point, you're probably spending a lot of money as you'd need to use some hosting service to handle multiple servers.

[sand holly]

How about using this plugin? https://www.unrealengine.com/marketplace/en-US/product/host-migration-plugin/questions

Like when the host leaves, the server gets a new host?

[sinful tree]

Can't speak to it, it's not something I'm familiar with.

[sand holly]

But technically would it work?

[sinful tree]

I have no clue.

[sand holly]

Hmmm okay well very interesting setting up multiplayer is actually such a hassle lol

Thank you for your insights

[fathom aspen]

You can ask the one who made it there in the comments or contact him

[sand holly]

Good idea, will do!

[quasi tide]

It'd be interesting for you to ask someone trying to sell their plugin, if it works or not and they respond with, "nah"

[sinful tree]

XD

[sinful tree]

I will say this, if it does work, it's probably a ton of data that would need to be transferred over the network constantly (eg. you lose the benefit of actor relevancy, all players would have to know where everything is and what it is doing). It's probably still running as a listen server, and upon the host disconnecting, the new host's game launches their own listen server and is set up as it was before the host disconnected, then the other clients would be attempting to reconnect. This means its also probably not seamless.

[sand holly]

Yes but I don't really see another alternative because I don't want the server to shut down when the host leaves...

Idk if you've ever played overwatch, there is a custom games feature in which you can also setup your own servers

When the host leaves, automatically another person becomes the "leader" of the server

[quasi tide]

Yes. Host migration.

[sand holly]

But in OW it's seemless, I wonder how they pulled it off

[sinful tree]

But when the host leaves, how quickly is the transition to the new host? Is it seamless?

[sand holly]

Yess

[sinful tree]

That probably means it was set up to be a P2P networking model from the get-go. All clients would have all the data, know all the states, share "rules" and determine if something happening is valid, one player leaves, the rest keep playing as is.

[peak sentinel]

I know the owner of the plugin, so I know how it works a little bit

its actually basically how Datura explained

everyone saved the state of the world, then loads it

[sand holly]

Does it affect performance?

[peak sentinel]

never tried

But just assumption: it wouldnt

it just saves transform, actors etc.

my biggest worry was the size of the saved data

but owner said it'll be around a few kbs

biggest problem of that plugin is, its exploitable

since everyone saves the data locally

you can change it and become host somehow

[sand holly]

Can hosts easily exploit a game

even if it is just a normal listen server?

[peak sentinel]

not hosts, everyone

everyone can exploit a listen server

no way to fix it

thats why dedicated servers a thing

data is in somewhere far away in a server lab

you cant modify it

[sinful tree]

Um

That's not entirely true.

[sand holly]

gawd dayum

[peak sentinel]

which one

[sinful tree]

If you're the host, then you have control of the server, so yes, you can do whatever you want to the server.

Just because it's a listen server doesn't mean that players can exploit it.

[peak sentinel]

true

the problem is, hosts are players

thats what I meant to say

but Im aware its poorly formalized

[sand holly]

So what would be the best option if you want a system where players can create a server that lasts until there are no other players in that server?

[sinful tree]

If you want a seamless system in unreal, then when a player wants to start up a server, they're making a request to launch a dedicated server on some hosting platform that you've set up, and then that player joins it. Others can join by searching for it/using sessions. If the original player that start the server leaves, the game still continues without them. Once all the players leave, the server shuts itself down.

[quasi tide]

The easier approach pretty much.

[sinful tree]

But $$$

[quasi tide]

Provide server binaries. Have them set it up themselves 🤣

[sand holly]

Yeah 😭

[sinful tree]

He's wanting the game to continue without having to worry about the server / host going offline.

[quasi tide]

I'm aware

[sand holly]

Well what part of it costs money

[sinful tree]

Well, you're either going to be opening up your own data center to house the servers required, or you're going to be paying a hosting service (like AWS) to run those servers for you. Both cost $.

That's where the benefit of letting players run their own dedicated servers.... They then are paying that cost.

[sand holly]

Literally or figuratively????!!!

[quasi tide]

Literally

[sand holly]

What I don't want the players to pay for a server then no one would play 😂

[quasi tide]

Not true in the slightest.

People love community servers

[sinful tree]

In the early days of networked gaming that's basically all you had.

Had to boot up GameSpy and find people running their own Team Fortress servers and join some 2fort4.

[sand holly]

And those people payed with money for a server?

[sinful tree]

Sure. Sometimes it can be as simple as just running an older computer in your house.

That still costs money.

Power, internet usage, etc.

If you host the server, you are paying for it.

[sand holly]

So let me get this straight, i can implement:

• A listening server system where the player is the host of the server. This is easily exploitable and the server shuts down once the host leaves

• Set up a hosting platform and let the player connect to a dedicated server hosted there. This costs a lot of money for me

• Let players pay to create dedicated servers. This costs money for the player and gets shut down once the player turns their computer off

[graceful flame]

What is the process to figure out how much it will cost to host your own servers? My guess is that you first need to determine how much cpu/memory is required to run one instance of your game and then try to find the best option where you can fit as many instances as possible into a single server without affecting performance. Then you also have to consider bandwidth costs...ughh

[sand holly]

Correct me if im wrong

[graceful flame]

Could also do a mix of hosting options. Let players host it themselves and play with friends, host some dedicated servers on your own and allow for community servers to thrive on their own as well.

It depends on your game

If you're making something like a co-op horror game or whatever then it makes sense to stick with listen as small groups of players are probably friends and cheating isn't all that big of a deal.

But if you're making a game for a larger amount of players per game it makes much more sense to go down the dedicated server path.

[sinful tree]

Listen servers are only exploitable in the sense that a player is the host and they have control over the hardware the game is running on, thereby they can tamper with the memory of the game allowing them to do things that may not necessarily be valid.

If you allow players to create dedicated servers, it's a similar issue - they have control of the hardware the game is running on, so they can tamper with it. The dedicated server doesn't necessarily mean they're running it on their own computer, they can host it somewhere else if they decide that has 24/7 uptime, but that's up to their discretion.

[sand holly]

I want the servers to be like a freeroaming space where players can PvP freely, chat and trade stuff

[graceful flame]

So like an MMO?

[sand holly]

In a way, but like getting your abilities and stuff in a separate single player mode

[graceful flame]

Unlocking stuff in single player that can be used in multiplayer will result in lots of cheaters who are able to unlock stuff instantly.

[sand holly]

Is a singleplayer mode that exploitable?

[graceful flame]

Single and listen are exploitable, even dedicated although to a lesser degree

[sinful tree]

Again, if you have control of the hardware the game is running on, you can manipulate the game.

[sand holly]

Okay so what if I have an offline story mode where you unlock your stuff normally, and then in the online mode you can customize everything freely

[graceful flame]

Your game is just a process running on your computer. Any process can have its memory altered because well the memory is just there physically on your own computer. So in other words you can boot up a cheat engine and start changing the memory around to make the game do stuff without having to actually do the thing you designed the player to do. They can just hunt around and find the bit of memory that flips the switch to unlock all abilities...etc

[sinful tree]

If you allow players to upload their "saved data" to represent their character in multiplayer, then that saved data could've been cheated.

[graceful flame]

Save Data in unreal engine is also not secure. There's websites where anyone can simply upload their save file and it allows them to edit the values and re-save it.

[young kestrel]

Even AAA games struggle with that.
Cheating in NfS is as easy as in manipulating some numbers in your memory.

And that's a multiplayer game with the ability to play locally.

GTA online has the exact same issue.

[sand holly]

Scrap the idea of transferring data between offline and online

[sinful tree]

Then you're having to save player data yourself which will cost you $$$ for database storage/usage.

[graceful flame]

So even if you were to use an external database server that you have full control over to manage the player's access to unlockables. That STILL isn't secure if its a single player game because the functions that reach out and make a request to the server can still be triggered manually by altering the memory.

Therefore the only secure way is to use a dedicated server which reaches out to an external database to manage player's access to unlocked things.

[sand holly]

Jesus...

[sinful tree]

Security is hard if you want to make it secure.

[graceful flame]

I'm currently in the process of setting up a system like this for my game. It all comes down to a few JSON POST requests that are being sent from a dedicated server to the other database server. If those URLs were to leak then anyone could simply boost their high score or whatever just by sending authenticated POST requests.

[sinful tree]

I could throw a masterlock on my shed, and most people wouldn't care to go in, but someone with knowhow will know that lock will fail within 3 seconds if they could get to it.

[young kestrel]

By the way, if someone knows the answer to this question that'd be great! Thanks! 🙂

[fathom aspen]

Haha it works™️

[sand holly]

Why must people hack 😭😭😭

[graceful flame]

You mean like this ---> https://youtu.be/bfDPtt-bnAI?t=49

[sinful tree]

Exactly.

[dark edge]

Yeah nobody plays Minecraft or Valheim or TF2 or GarrysMod

[graceful flame]

It takes that dude like 5 seconds to unlock that LOL

[sand holly]

I think I'm gonna have to rethink my whole concept a little bit now that I've gathered this information

[sinful tree]

I decided to get a lockpick set myself to play with because of LPL.

[graceful flame]

If Valheim was more like Rust.... wow that could could of been such a crazy multiplayer experience.

Imagine a horde of enemy viking ships appearing on the horizon as the town's people start screaming and running around franticly.

[sand holly]

Wait what about easy anticheat

🤔

[sinful tree]

Same problem. Something executing on your computer, you have control of. Nothing stopping you from cheating the anti-cheat system.

[graceful flame]

My (limited) understanding of something like easy anti-cheat is that you can pick an anti-cheat partner to work with and they perform a security audit of your game. You probably also pay some sort of license fee and then they make it so your game works with their exe which runs on your player's hardware to detect cheat processes.

[sand holly]

Okay so scrap that idea 😂

[sinful tree]

And that still doesn't protect your databases etc.... If you have something exposed on the internet, people don't need to even run your game to access it and send commands to it.

[graceful flame]

There's also tons of things you can do with the design and development of your game to reduce cheating. For example Valorant came up with a custom "fog of war" system with their game. Essentially they hide all non relevant player characters (even when behind walls) and only reveal them at the very last moment. This helps reduce the effectiveness of wallhacking because you can't see an enemy behind a wall until they are just about to step out into line of sight.

[young kestrel]

Technically you could do some kernel level of anti cheat... But...

[sand holly]

I think I'm gonna have to go full online or seperate the two gamemodes

[fathom aspen]

Correct the server would have all the 12, as it's the one who spawned them all.

[sinful tree]

BIOS level Anticheat yo.

[young kestrel]

Thanks. So my stuff works as intended. I already thought I did something very very wrong.

[graceful flame]

My game is also a mixture of single and multiplayer. For the single player part its entirely PVE and there are some unlockable perks that aren't all that difficult to obtain in the first place. The unlockable custom events make a request to the external database which reads and validates the request. Sure it can be hacked but I don't really care because the unlocked item isn't all that amazing.

The unlockables on the multiplayer side of things are far more important for gameplay.

[left dagger]

is there anyone that could help me with logging network related logs, im using steam and using listen servers and keep running into weird random disconnecting client and host side and cant seem to find a way to log what is happening

[sand holly]

Does this cost money

External database

[graceful flame]

yea

[sand holly]

:(

Broke

[graceful flame]

Well you could try to host your own but a cloud solution is much better.

[young kestrel]

Yeah. Cloud solutions are actually pretty decent.

[graceful flame]

Cloud database is cheap though.

[sinful tree]

And in some instances, some companies have "free tier" access for development purposes that has certain limits on storage and access rates.

[graceful flame]

But be warned they can be very VERY expensive if you screw things up. They scale automatically and there's no hardware to manage.

[sand holly]

I think I'm just gonna give up on the idea of transferring data between modes

[sinful tree]

Yeah AWS charged me $5 for some bloody error logging on a free database -_-

[graceful flame]

An example of doing something wrong to result in a huge cloud bill would be like writing some buggy code that does an endless loop of making some change on database table or something like that.

I have a few Firebase apps that I'm hosting for basically free. The highest I've seen my bill is like $0.03

[sinful tree]

Event Tick -> Write to database (All Player Data)

[graceful flame]

Normally uploading images over and over again isn't all that big of a deal, but it IS a big deal when you're running a website that is hosted in multiple datacenters across multiple regions.

[sinful tree]

omg that's horrible XD

[eternal canyon]

You can find a version of this in ShooterGame btw

[graceful flame]

Oh? Do you happen to know which folder or file?

or perhaps a keyword I can search for?

[static flare]

I'm struggling with making clients possess a server-owned pawn. I was thinking I could just call a Server-RPC on the pawn, but since the calling client doesn't own it - the call is just dropped.
I understand this is by design.
I assume I have to tell the server to give "me" ownership over this pawn before possessing it (or have the server make "me" possess it), but how should I do that if I can't call the server through that particular pawn? Am I supposed to route the request through my PlayerController/Pawn? Like make a generic AMyPlayerController::ServerRPC_RequestPawn(APawn* Pawn) or something, which I would call whenever my current pawn interacts with the server-owned pawn, and then pass the server-owned pawn?

[left dagger]

just place the script somewhere like the player controller

it just needs to be something that is owned by the client that way in can call rpcs

[eternal canyon]

In the character cpp

There’s a should replicate function if I remember correctly

Where they implement a version of it

Tho it’s not perfect

[graceful flame]

Ahh yes, that makes sense.

I'm compiling already right now but I'll have a look for that code in shooter game. Thanks @eternal canyon

[static flare]

Is there a fancy way of getting the PlayerController of the client that is calling a ServerRPC, or would I have to pass it in the RPC?

Holup.. I'm using my frontend-brain again..
If I call a ServerRPC on my PlayerController, then the exectution will be on the server - but it will still be on MY PlayerController.. right?

[sinful tree]

Correct

[iron crest]

Hello, I have no clue if this is a ue bug or replication bug but whenever I try to equip (Capes) And (Masks) It Cancels either or out, here is the code

Im On ue5

[sinful tree]

Instead of having multiple RPCs, consider passing along the integer through the RPC, then setting which mesh to use based on the integer.
Your "SwitchCloak" RPCs are modifying the "Mask" mesh. Are you sure that's what you wanted it to do?

[iron crest]

Oh Shoot, I didnt notice that I was changing the mask mesh on the cloak lol that fixed it, thank you

[sinful tree]

Much cleaner, less nodes to deal with. Easy to add more options.

[iron crest]

Oh, this does look like a better way, I hate dealing with all my nodes, thanks for this 👍

[left dagger]

yeah so youd want the input to call the rpcs on the player controller and from there they can call any event and it will be replicated, for instance, i possess a car by first letting the player controller know then the pc tells the server and then the server tells the car

[fathom aspen]

I didn't follow-up, but this won't run for non relevant clients. Are you aware of that @iron crest ?

[sinful tree]

True 😛

[left dagger]

if you want skeletal mesh updates to replicate youll need a setup that sets the skeletal mesh remote as well as calls it on the client, not just calling it on all

[quasi tide]

You need OnRep

OnRep for state changes - IE, changing the mesh of something.
RPC for one-off events - IE, an explosion effect

[fathom aspen]

This one literally talks about how you change a mesh, so perfectly fits your example: https://vorixo.github.io/devtricks/stateful-events-multiplayer/ @iron crest

[iron crest]

Perfect Thank You, Ill Check This Out, Seems Useful

[static flare]

Is it always illegal to call Possess from client? Even if my PlayerController owns the pawn?

[sinful tree]

I think you could possess a locally spawned pawn, but not a replicated one spawned from the server.

[fathom aspen]

Only runs on the network authority (where HasAuthority() returns true).

[sinful tree]

There is a setting "bCanPossessWithoutAuthority" in the code.

[fathom aspen]

Hmm that's new to me.

[sinful tree]

Either way, I think it's probably a bad idea to possess a pawn locally only in a multiplayer game.

[fathom aspen]

Yeah honestly if it's that way by default I won't change it. Especially that stuff like this is authority

Wondering what the special cases to turn that on

[static flare]

I see.. If I have a server-spawned replicated actor and the server called SetOwner(SomePlayerController), what would the "owning" client's authority be? Not Authority, but one of the Proxy-values? (i.e. HasAuthority is false?)

[fathom aspen]

A replicated server spawned actor would have Role_Authority on server

On client it's autonomous for you and simulated for others on your machine

At least for controllers it's that way

[static flare]

Wait, so the NetRole doesn't change when the actor's Owner is changed? Are they completely unrelated aspects of ownership?

oh shit, there's a RemoteRole too. I have to look more into this tomorrow.. 😴

[fathom aspen]

Yeah there is LocalRole and RemoteRole. Not really sure about the details, but yeah LocalRole stays the same

Has to write a blog post about it eventually

[valid imp]

I have a hard time finding a definitive answer on the web: what is the best way to send a large amount of data (more than a normal RPC) with Unreal?
Given that TCP sockets are not really supported..

[sinful tree]

TCP Sockets.

You can potentially make the data into chunks and send it through multiple RPCs and reconstruct on the other end.

[valid imp]

The problem with TCP sockets is that Steam multiplayer isn't happy with opening more ports.
Sending data into chunks and reconstructing is probably the best idea, is something built in Unreal for that?
I don't think there is, but I don't see why, it sounds like a common use case.

[sinful tree]

I don't think there's a catch all solution, you'd have to make it yourself. What kind of data is it you're needing to replicate?

[woeful ferry]

That’s the worst thing with Steam multiplaer. Pretty limited, it is what it is.

Currently working on voxels with steam multiplayer and damn you have to think sometimes

[valid imp]

Something more or less voxel-like. It's not terrain but it's still 3D points with properties each, that I generate on the server around players and I now want to send to clients.
I could just limit the number of amounts of points I send to fit the 65kb limit, or I could compress a bunch of them into a binary, slice the binary, send it into RPCs and retrieve it.
For the binary strategy, I don't see why there couldn't be a catch all solution though. It wouldn't depend on the actual usage of the binary data exchanged.

[dark edge]

That should be a repnotify

[quasi tide]

Some internet explorer speed you have there Adriel 😅

[fathom aspen]

He saw them, but repetition is 🔑

[finite scaffold]

I'm just about to start with UE. For doing a MP game, should I learn how to do multiplayer first, or do the base game and then implement mp?

[fathom aspen]

It's not safe to start working with MP right away even if you had UE knowledge, how if you don't have any. I would suggest you know UE first, then try and indulge in MP. This is the MP starter pack: #multiplayer message

[graceful flame]

If you're a solo dev and your game is going to have a multiplayer experience then there's plenty of other stuff to learn before you start working with multiplayer such as getting comfortable with blueprints, level design, material design, character design, audio design and AI. Only then does it make sense to spend time making things replicate and learning about RPC's and organizing your code into the proper base classes and implementing a server authoritative structure.

If you're working in a team to make your first multiplayer game I'd suggest splitting the work up into programming and design. One person makes things work in both single and multiplayer while the other person makes things and makes sure they look good.

[finite scaffold]

I'm in the planning stage and began to learn the basis. I'm an artist about to become a solo dev by now. So I will follow your advice and learn and get comfortable with ue bases, and then start again to do the mp

[graceful flame]

This is the best, free and official learning resource library: https://dev.epicgames.com/community/learning

[dark edge]

You're not streaming the entire voxel world, right?

Are you at least having a base set and diffs to it?

[limber gyro]

does any one know the diference between private and public connections in this node?

[fathom aspen]

/** The number of publicly available connections advertised */
int32 NumPublicConnections;

/** The number of connections that are private (invite/password) only */
int32 NumPrivateConnections;

[limber gyro]

thanks

another quick question

do these options look good ?

putting the name of the map first is enough right?

[fathom aspen]

Correct

btw it's called MaxPlayers

/** Maximum number of players allowed by this server. */
UPROPERTY(globalconfig)
int32 MaxPlayers;

That gets auto assigned

In case that what PlayersPerMatch meant

[limber gyro]

that one is actually my variable

[frosty trail]

Are there any ways to check what is/isn't being replicated in the editor?

Getting a bunch of LogProperty: Error: Replicated TMaps are not supported. logs, but I'm 95% confident I'm not replicating any TMaps.

[fossil spoke]

Its likely that you are.

[frosty trail]

Yea, but not that I can find

😛

Even after going through everything in the reference tree, no TMaps that I'm setting to replicate

[fossil spoke]

Find where that error is in code and set a breakpoint?

[sinful tree]

Perhaps you're replicating a structure that has a TMap in it?

[woeful ferry]

The voxel world itself is not replicated, just through a seed 😛

So dont worry lol

[humble edge]

My dedicated server stuck at Bringing up level for play and doesnt show Engine Initialization. Help!!! anyone who can help me.

[uncut schooner]

How do I do WLAN mobile multiplayer

[thin stratus]

By connecting via IP to the local IP of the Phones?

[celest pulsar]

On Iphone, i got some net work error. Unreal@4.27.2, OnlineSubsystemNull. But it's success to create and join online session.

[UE4] [2022.08.09-06.40.57:252][191]LogNet: UIpConnection::HandleSocketSendResult: Socket->SendTo failed with error 37 (SE_EHOSTUNREACH). [UNetConnection] RemoteAddr: [fe80::33:511e:d503:e311]:7777, Name: IpConnection_2147479383, Driver: PendingNetDriver IpNetDriver_2147479384, IsServer: NO, PC: NULL, Owner: NULL, UniqueId: INVALID Connection beginning close timeout (Timeout = 0).

[sage lodge]

Does someone know why the Set Collision Enabled isnt working?
I disabled it and now after a delay I am trying to enable it again, but it doesnt work
At the beginning of this code I added 2 custom events on running on multicast the 2nd on run on server
Everything is working (replicated too), only the collision isnt working

[glacial ermine]

Hi everyone, are there any open source examples of a dummy multiplayer game? Nothing more complex than just allowing a few players to join a server and run around one of the template maps.

Which I could just download and use that is

[winged badger]

shooter game example should work

quite a few games started as a shooter game, then evolved

[fathom aspen]

Or Lyra

[winged badger]

i heard only weird/bad stuff about lyra

people messaging me "look what they did here weird"

[fathom aspen]

They were happy till that teleport exploit was found xD

[fathom aspen]

Haha nothing there makes sense tbh

[fathom aspen]

For reference: https://vorixo.github.io/devtricks/shootergame-vulnerability/

[winged badger]

one was matching some manually assembled strings with class names to pick which class of debug controller should you use

that was very awkward

[fathom aspen]

Hell nah

Seems like they made it in hurry

Also the data driven approach overcomplicates stuff

[winged badger]

ah i know about that one

should bring fond memories for @chrome bay 😄

[fathom aspen]

Haha James should have went crazy over it

[winged badger]

HLL had that iirc

[fathom aspen]

Yeah it's mentioned in the post

[winged badger]

so did SCUM

[fathom aspen]

Wow, it really shows that games were built upon it lol

[chrome bay]

Yeah, found that pretty early on 😄

Tbh that's just the tip of the iceberg when it comes to working shootergame hacks

Lyra isn't any better

Took about 2 seconds to make a weapon speedhack

[fathom aspen]

It's crazy how easy it's to miss these stuff at development

Was you the one who fixed it?

[chrome bay]

tbf I don't think they were really thinking about making things cheat proof when building the samples

Yeah though I "fixed" it because we essentially did our own ballistics system that required getting rid of all that anyway

[fathom aspen]

Oh yeah it was all ditched then

[azure beacon]

Hi folks, I'm having an issue with client actors and movement. Hopefully this is something really simple that I have overlooked.

I have a multiplayer game based on the top-down game example. The game starts and spawns two actors - one for client and one for server. Both of these actors function correctly, as you would expect.

However, when respawning the client's actor (Actor instance is deleted, and then a new one is spawned using the same blueprint), that actor is unable to move correctly and the error message "Movement not allowed" is printed to the console.

When it is respawned, it is assigned a player controller in the same way as when we created the initial client actor, so I'm really not sure why it's failing. Could anyone shed any light on this?

[static flare]

I need an action triggered (client-side) on a newly possessed pawn, so I was hoping I could find and override something like APawn::OnPossessedBy(APlayerController), but it seems no such thing exist.
I can only find the other way around: APlayerController::OnPossess(APawn). Do I have to override this in the PlayerController and specifically check if it's a certain pawn class, then call the pawn-function from there?

Or are there other ways of being notified inside the Pawn when it's being possessed? I can see that PawnClientRestart should do something similar, but "restart" isn't that well documented so I don't really know what it means..
I don't want to clutter my PlayerController-class if I can avoid it.

[unborn light]

Hello everyone, I have a problem, I dynamically load static mesh from an external server, then load it through the path and add it to the inventory/building system. Locally, everything works fine, however, in multiplayer, other users do not see this static mesh. How can I replicate this static mesh?

[thorn wraith]

Hello all,

I am researching in creating a MMO using Unreal. I know that this is a huge undertaking but I might make something really simple. I am using this project as a guide for learning so that I can touch many aspects of Unreal and learn as needed. Like I said, it is going to be a pretty "simple" MMO for my learning purposes.

Currently, I have some very basic movement for a main character and I am currently looking at implementing an inventory system and also utilizing the GAS for my abilities. But before I get too thick into the gameplay side of things, I want to make sure that I build this with the view of MMO correctly so that I do not have to go back and spend hours redoing things.

My first set of questions are pretty basic.

1. I was reading that for MMO, it is best to run the entire game on a headless server. Does this apply to Unreal?
   1b) I know that Unreal runs the client-server model where a server hosts the game. When creating an MMO, do I make the game as if it is a single player game where the project implements everything and later it turns into the headless server to monitor the states? Or is there more special implementations that I need to consider?
   1c) As a follow up. I am working on an inventory management system. For now, do I setup it up "normally" in my project for now? Or are there any special considerations that I need to think about when moving over to the headless server?
2. I am reading about networking from the Unreal documentation. For the MMO, can I consider it as one big multiplayer game or are there additional considerations that I need to take into account that are not mentioned in the documentation?
3. Can anyone recommend some good resources for me look into implementing MMO with Unreal?

[fathom aspen]

In the staticmesh actor class you got Replicates flag. Set it to true.

[unborn light]

already done, didn't help

[fathom aspen]

Why are you setting it to replicate at runtime? And anyways this won't work when you SetStaticMesh, unless you do it using an OnRep

[unborn light]

blueprint also has replication installed

[fathom aspen]

Does the spawned actor replicate?

ItemBuilding

[fathom aspen]

So the actor is replicating though you can't expect the set skeletal mesh to replicate too, because that is done locally

Even if you replicate the component it won't work

So my point still stands you need to set it when the actor replicates for example.

OnRep_ActorHasReplicated->SetStaticMesh

[unborn light]

default staticmesh builds perfectly, but which is loaded does not appear

if I try to output the class name, it outputs an empty string

[unborn light]

set SceneRoot and StaticMeshComponent replicated, doesn't help

[fathom aspen]

[unborn light]

this didn't help too

[fathom aspen]

I'm not sure if there's something I'm missing but again this is how I would do it

[unborn light]

I think the problem is that there is no static mesh class on the server that was loaded on the client, so it can't deliver anything

[fathom aspen]

The thing is that BuildingSimMesh you are passing should be replicating too, by the time you set, which if not attached to the actor spawned there you can't guarantee they replicated at the same time

[unborn light]

i try to set BuildingSimMesh variable replicated

[radiant nebula]

I've got this problem where the host of the game shoots straight out from the camera to the forward vector but the player who joins the game shoots down even though they are looking flat (the angle of the gun is where their camera is looking). I'm not to sure what's going on, please help if anyone knows.

[glacial ermine]

Thanks!

[unborn light]

when i use local static mesh all works fine, but with downloaded one - unknown type

[final turtle]

Hi 🙂 I'm looking for a function which is called on the dedicated server when a client leaves the server (on graceful disconnect, client crash, network connection crash...). The main Problem is that I need to have access to the Pawn (which seems to be already destroyed in AGameMode::Logout). Is there any overridable (C++) function that satisfies these requirements?

[winged badger]

void APlayerController::Destroyed()
{
    if (GetPawn() != NULL)
    {
        // Handle players leaving the game
        if (Player == NULL && GetLocalRole() == ROLE_Authority)
        {
            PawnLeavingGame();
        }
        else
        {
            UnPossess();
        }
    }

    if (GetSpectatorPawn() != NULL)
    {
        DestroySpectatorPawn();
    }
    if ( MyHUD != NULL )
    {
        MyHUD->Destroy();
        MyHUD = NULL;
    }

    if (PlayerCameraManager != NULL)
    {
        PlayerCameraManager->Destroy();
        PlayerCameraManager = NULL;
    }

    // Tells the game info to forcibly remove this player's CanUnpause delegates from its list of Pausers.
    // Prevents the game from being stuck in a paused state when a PC that paused the game is destroyed before the game is unpaused.
    AGameModeBase* const GameMode = GetWorld()->GetAuthGameMode();
    if (GameMode)
    {
        GameMode->ForceClearUnpauseDelegates(this);
    }

    PlayerInput = NULL;
    CheatManager = NULL;

    Super::Destroyed();
}```

@final turtle

the PawnLeavingGame is what destroys the Pawn too

[final turtle]

@winged badger Thanks! I gave it a try and the PawnLeavingGame function sems to work perfectly for my usecase!

[thorn wraith]

Hello all,

I am researching in creating a MMO using Unreal. I know that this is a huge undertaking but I might make something really simple. I am using this project as a guide for learning so that I can touch many aspects of Unreal and learn as needed. Like I said, it is going to be a pretty "simple" MMO for my learning purposes.

Currently, I have some very basic movement for a main character and I am currently looking at implementing an inventory system and also utilizing the GAS for my abilities. But before I get too thick into the gameplay side of things, I want to make sure that I build this with the view of MMO correctly so that I do not have to go back and spend hours redoing things.

My first set of questions are pretty basic.

1. I was reading that for MMO, it is best to run the entire game on a headless server. Does this apply to Unreal?
   1b) I know that Unreal runs the client-server model where a server hosts the game. When creating an MMO, do I make the game as if it is a single player game where the project implements everything and later it turns into the headless server to monitor the states? Or is there more special implementations that I need to consider?
   1c) As a follow up. I am working on an inventory management system. For now, do I setup it up "normally" in my project for now? Or are there any special considerations that I need to think about when moving over to the headless server?
2. I am reading about networking from the Unreal documentation. For the MMO, can I consider it as one big multiplayer game or are there additional considerations that I need to take into account that are not mentioned in the documentation?
3. Can anyone recommend some good resources for me look into implementing MMO with Unreal?

[worn wagon]

Would it be acceptable to replicate things using the InitialOnly condition, so that players who join "late" get the current state of everything, then past that variables are kept in sync using only RPCs? I'm trying to think if there are scenarios in which they would not be synced correctly, such as when an actor is no longer relevant. Do the multicast RPCs still get triggered if the actor is not relevant?

The reason I need to do this is because I have 2 properties that work in tandem that must be replicated, but there is no way of knowing which is replicated first. I need to run functionality only when both have been replicated, but there is also no way for me to logically pair them up.

Everything would be so much cleaner just using RPCs, but I want to know I'm not shooting myself in the foot here somewhere down the line.

[fathom aspen]

No.

[fathom aspen]

Put them in a struct

Struct don't replicate atomically though by default

You will have to make them so

Stateful = replication
transient = RPCs

No way around that

[worn wagon]

[static sable]

hi, isn't replicating (repnotify) USTRUCT with multiple properties from server to client just a bad practice? I mean shouldn't RPC be used instead when more than one property needs to be replicated?

[worn wagon]

So I can't just slap a replicate property on it?

[fathom aspen]

You would have to implement NetSerialize in there

[worn wagon]

The 2 properties I need replicated are an array of uobjects (weapons) and an enum (the active weapon slot)

[worn wagon]

Hmm okay, I guess I need to look into that.

[worn wagon]

If this is the case then i'm not sure what I should do

[fathom aspen]

Same questions asked by Ghetto. See what I answered above

Nothing bad about that. What's bad is using RPCs

[worn wagon]

I need things replicated in a timely manner though.

When a player swaps weapon the change needs to show immediately

Ofc I can do both but still

[fathom aspen]

Do it locally then, still replicate it

[worn wagon]

Oh I meant for showing other players weapons, I do that stuff locally already for the local player

[fathom aspen]

You would have to wait to replication to occur I guess

Even if you multicast that, the change isn't going to be faster

[static sable]

so in NetSerialize you'd be able to tell when to send them over to the client? only if both weapons and the active weapon slot have been updated... how do you manage to tell if they both have been updated?

..before sending them over

[worn wagon]

If I'm creating a replicated actor and then storing a pointer to it in an array which is set to replicate, how am I guaranteeing that the actor is replicated before the array of pointers. Isn't it possible the pointers are just null on the client? I haven't had any issues but I realised I'm not entirely sure what's happening under the hood.

[chrome bay]

Definitely not

[static sable]

like simple example, I have this:

struct {
  int x;
  int y;
} struct_s;

how can I tell that both x and y have been updated and only then send that struct to the client. Won't they come as 2 separate updates likes this:

// this is repnotify
struct_s s;
s.x = 1;
// sending over to the client
s.y = 2;
// sending over to the client

[chrome bay]

NetSerialize() just means both properties will always be sent and received together. Still no garauntee however that a reference to another actor is valid when you receive it

[chrome bay]

If you change the properties in the same frame, they will arrive in the same update

[static sable]

I see thanks

then I have to redo my multicasts 😄

[chrome bay]

State = Property, Event = RPC

If you don't follow that general rule, you can't expect replication to work properly

[worn wagon]

So what's happening if I create say a weapon actor that is attached to a component on the player, then set a replicated reference to it in the same function. How do you know that the pointer won't be null on arrival.

[chrome bay]

You don't

But the OnRep will be called again when the actor pointed to becomes valid

[worn wagon]

So I should use RPCs for that?

[chrome bay]

No, you still use properties and OnRep callbacks - but you cleanly handle it when the property is null

[worn wagon]

Ah I see, that is very useful to know

[chrome bay]

OnReps will be called again when the object/actor pointed to becomes valid

[worn wagon]

That seems really important to know damn

[unborn light]

can some help with this #multiplayer message

[chrome bay]

Yeah, without that it's hard to really do anything safely with object instances

[worn wagon]

And for a replicated tarray of weapons and a replicated enum for the active weapon slot, I should put them both in a struct? Since I need to do some functionality only when both have been replicated, but there's no way to tell when that has happened because I can't pair them up.

[worn wagon]

wdym by "downloaded one"

[chrome bay]

Not sure exactly what you mean there

[unborn light]

i dynamically load static mesh from external server and load by path

[grave notch]

1. Dedicated server in unreal is headless, yes
   1b. You have to make game as multiplayer from the beginning, im not sure what you mean by "turn into the headless server". You need to understand what server and client are and how to work with them, what server responsible for and how it communicates with clients etc.
   1c. 1b already answers it
2. Its more than just multiplayer, but you can think about it as big multiplayer game for now, and then implement additional logic for MMO specifically, like saving state of the world.
3. No idea

[unborn light]

than i want to place it, but can't

[worn wagon]

I have 2 properties that get replicated, and I need to execute functionality only when both have been replicated. An RPC would make it easy but then there's state issues, so I need to "pair them up" somehow. WizardCell told me I should put them both in a struct and replicate that with NetSerialize.

[chrome bay]

It's up to you really, if it makes sense to put the properties together then having them in a struct seems sensible. NetSerialize() may not help a great deal

[unborn light]

i need some way to replicate static mesh that dynamically loaded on client

[worn wagon]

Really I'm just asking how you would approach something like that, pairing up 2 replicated variables to ensure they are received together.

[chrome bay]

You could pair them yeah. NetSerialize at least ensures the struct cannot be in a state client-side that it was never in server-side

(besides null pointers obviously)

[thorn wraith]

Thank you for taking your time in answering my questions!

Yes, I figured that I need to make it as multiplayer from the beginning.

I am reading up on the UE documentation on multiplayer because like I said I want to start implementing some of these before I get too far and having to redo the entire structure.

So far, this is what I am reading through:

https://docs.unrealengine.com/5.0/en-US/networking-and-multiplayer-in-unreal-engine/

But I think that the perspective is from a fps multiplayer game. Which is fine because I believe mmo and fps will use similiar systems. And then later I can add in more specific systems for the MMO.

[unborn light]

Jambax, mb you can help me something, i need some way to replicate static mesh that dynamically loaded on client

[chrome bay]

Dynamically loaded? What do you mean?

Also replication is Server->Client, not the other way around

[quasi tide]

Please, do not jump straight into doing an MMO when you don't know multiplayer. Do at least a few small games. Some even in SP to learn UE as an engine.

[unborn light]

load from external server by HTTP and then load by path

[grave notch]

thats true, its better to start with single player, then multiplayer and then MMO

[chrome bay]

What are you loading though? A path to an existing file? Or are you building an entire mesh at runtime?

[unborn light]

i load .usdz file and import in runtime, and then get only static mesh from it

[chrome bay]

You can't replicate that. If the file is stored on some other server, just tell other clients what the file is and have them retrieve and build it themselves

[unborn light]

that is, all users should download the file and get static mesh from it and continue to work with it? And there is no way to somehow transfer this static mesh to everyone?

[chrome bay]

Not with gameplay replication logic no, apart from anything it'd be way too much data for a reasonable mesh

[thorn wraith]

I understand the risks and the sheer complexity of doing everything. I am using this as a sandbox to learn different components. That is the best for me to understand what is going on.

Thankfully, there is a portion that I do not have to do which is asset and animation creation. All those I already have. Just need to focus on the gameplay part.

I am taking my time with this and am understand this will take time.... Alot of time. I am sure that I will be picking up other projects along the way. But this is like an itch that needs scratched every once in awhile

[unborn light]

ok, thank you very much, very much appreciated

[twilit anvil]

if there is quite big codebase written for a singleplayer game, how hard is to convert it into multiplayer?

[quasi tide]

Quite difficult.

Multiplayer introduces whole different approaches to the same problem in SP.

It's not a simple switch flip or "oh, I'll just throw some RPCs in here"

Not saying it can't be done mind you.

[graceful flame]

With that golden rule in mind, does it make any difference if a multicast has some nodes to execute directly on its chain, VS a multicast that only calls a single custom event which has the same nodes to execute.

Server-->Multicast-->Do this, do that, do some more of this, and finally that.
vs
Server-->Multicast-->Do this custom event
This custom event: Do this, do that, do some more of this, and finally that.

[quasi tide]

Not really. You're still executing the same stuff.

Unless you're talking about using RPCs for stateful replication.

[twilit anvil]

thanks, I thought so but, haven't done anything like that for such a scale and wanted some input @quasi tide

[worn wagon]

The only difference is you could call that event somewhere else, but you could also just call the multicast implementation function directly

[graceful flame]

Okay that confirms my thinking, but I wasn't 100% sure.

[sage lodge]

Does someone know how to fix it, this is a disappearing platform which comes back after a delay, but when it comes back the collision is weird, if you try to jump on it the character glitches and falls through it (custom event 1 is multicast custom event 2 is run on server)

[worn wagon]

Sounds like it hasn't moved on the server and it only moved on the client

[graceful flame]

So if a multicast has input parameters, floats, int, bools ... etc those are also sent over the network, right? It's a good idea to keep input parameters for server and multicast events to a minimum whenever possible. Right?

[quasi tide]

Send the information you need.

Just do your safety checks on the server.

[sage lodge]

What does that mean?

Would should I change

[graceful flame]

1 and 2 should be in reverse order. Overlap --> has auth --> cast --> (isValid?) --> server event

Server event --> multicast event
Multicast event --> timeline --> change material param --> set scale ...

Why is your platform collision screwed up? Because you're changing the scale of the mesh on the server only but not for all clients so it looks larger than it actually is.

[pallid mesa]

worth mentioning that Darnell mentioned that they might want to try fix it

but we are years beyond a secure Lyra

unless it somehow becomes a priority

[sage lodge]

I will try it out

[sage lodge]

now the glitching is gone, but still no collision

[graceful flame]

You're also reversing a different timeline

Perhaps you intended to reverse the existing one?

[umbral horizon]

Hi, there are some phases where I want the pawn to follow server movements. I can't use AddMovementInput from server. How should I go about adding movement from server? Any help is appreciated. Thanks

[sage lodge]

But isnt the timeline just for the mesh?

and the collision is attached to the mesh

hmm

what if I separate them

[eternal canyon]

virtual bool IsReplicationPausedForConnection(const FNetViewer& ConnectionOwnerNetViewer);

btw

this is what the function is called

[dark edge]

Why is everyone multicasting and not using repnotify for stateful stuff

stop multicasting so much lmao

[fathom aspen]

That's prolly the most repeated mistake here ^^

[quasi tide]

Multicast for life baby!

[graceful flame]

Not enough multicast!

[sage lodge]

What now xD

[grand mica]

Hey,
In my game when I run as client and run the game under one process the bots in the game seem to be moving but when I run it under multiple processes the bots don't move at all but their tasks get updated. Looks like something is not replicated. I have replicated the task enum, and turned breplicates to true but I am trying to figure what is not making it to move

[sage lodge]

I am still stuck on that collision stuff

Suffering … pain …

[grand mica]

@fathom aspen you got any hint for this?

[graceful flame]

Have you tried stepping through the code with breakpoints? F9 on a node to add a stop sign, then Play your game and it will pause automatically (when the node with the F9 stop sign is executed) , then press F10 to proceed to the next node and F11 to enter a node. If it doesn't pause on anything then you know your breakpoint didn't even run.

You can also hover your mouse over the pins to see the current data in a popup

[sage lodge]

Didn’t know that

So if I F9 the set collision and it doesn’t stop then the node isn’t activated

[graceful flame]

ah-ha! so now what you can do is move the F9 stop a bit further back and watch as the red pulsing lines show the flow of logic and pinpoint why it stops

[misty stirrup]

any good network plugins that push the limits of players higher?

[graceful flame]

not sure what your question is about, what do you mean by "limits"?

[sage lodge]

that was an example or a question xD

but I will try it

[misty stirrup]

running into issues w/ default ue4 networking where we have roughly a 100 player cap

[graceful flame]

like what sort of issues? do they only happen with a full 100 player server?

[misty stirrup]

performance issues on the server side

trying to find like a distributed server system, i only found one so far that's suppose to be releasing a plugin

the other one, the main dev got scalped by star citizen lol

[graceful flame]

yea i dunno, that's something i haven't done before

Question: Is there anything to be aware of with save game files for misc player settings in a multiplayer game? It seems that testing saving and loading with multiple clients using PIE is pointless because they all read from the same file.

Should I be using the User Index int slot? Is that just for splitscreen or something?

[celest bough]

I am trying to get a message to display when a player joins a game, but the username being shown is always the hosts name. Is anyone able to look at my code and possibly tell me what im doing wrong? Thanks ❤️

[umbral horizon]

I can't use AddMovementInput from server. How should I go about adding movement from server? Any help is appreciated. Thanks

[sinful tree]

This. You can't use GetPlayerController 0 in multiplayer on the server - it'll always reference the first player. You have the "New Player" pin on the event that you should be able to plug into this cast.

[celest bough]

I was looking at the pic just now and spotted that and started to wonder if that could be the issue. My reasoning behind that is because i assumed get player controller 0 returned the server pc since its being called in the game mode

thanks

and i didnt think it mattered if the server or the client called that event since its a server event anyway

[sinful tree]

Actually the more I'm looking at it, the more I'm getting confused XD
You are right, it shouldn't specifically matter in this case.
The issue is likely contained within these functions. Check what the UniqueNetID is (possibly print it out?) and see if everyone has the same Unique Net ID, or check the GetPlayerNickname function.

[celest bough]

i may actually try just including those 2 functions in the PC only and take them out of the initial GM step

[winged badger]

easiest way is just to do it from PlayerState

it holds the replicated PlayerName, and replicates itself

[celest bough]

do i need to set the player name in the player state?

[winged badger]

so as long as your server is immediately aware of Player's Name (and it doesn't need to be sent to the server when the game starts)

solution is as simple as PlayerState BeginPlay sends a message to whoever local player is

[celest bough]

im not sure i understand atm so il take a little peek at a player state. never actually used one before

[winged badger]

if you're using something like steam

you can pull the steam data from the net ID

and just send a message using their steam name

its an actor that belongs to a PlayerController, unlike PC its replicated to everyone

and there is an array in GameState called PlayerArray that holds all of them

[celest bough]

so instead of trying to do it from the game instance, i would instead call the "server - Issue liveplay event" from the playerstate using the local pc

[winged badger]

now, being replicated to everyone, as long as PlayerState has the data about PlayerName on server's instance right away (so you either joined from lobby, send a name in login url or are using something like Steam)

all PlayerStates on every machine will have the correct PlayerName at the moment they call beginPlay on that machine

[celest bough]

yeah im using steam

[winged badger]

which makes your life much simpler

[celest bough]

so from the post login event i can set the player state name using the incoming pc reference?

[sage lodge]

@graceful flame I tried the F9 on the Set Collision Enabled (Collision Enabled Query and Physics) and it stopped

[winged badger]

it might set the steam name correctly

on its own in the engine

i don't remember that bit

engine code for autoassigning players (nick)name is all ways weird and convoluted

but

[sage lodge]

@graceful flame the problem is the timeline ... the one behind collision enabled