multiplayer

[twilit radish]

They call the game instance in the end.

[rose egret]

open xxx error is handled by OnTravelFailure ? 🤔

[fossil spoke]

If you are using C++ you may want to look at overriding in the Engine

    /** Allows subclasses to pass the failure to a UGameInstance if possible (mainly for blueprints) */
    virtual void HandleNetworkFailure_NotifyGameInstance(UWorld* World, UNetDriver* NetDriver, ENetworkFailure::Type FailureType);

    /** Allows subclasses to pass the failure to a UGameInstance if possible (mainly for blueprints) */
    virtual void HandleTravelFailure_NotifyGameInstance(UWorld* World, ETravelFailure::Type FailureType);

[rose egret]

im writting some automation to launch headleass clients and I want them to shutdown if failed to connect or disconnected

[pallid mesa]

headless clients?

[rose egret]

thats guys , I go try, my code base has grown so that asking here is better than changing the code and waiting to compile

😁

[twilit radish]

You probably want to use the NetworkFailure one as that handles basically all scenarios from what I see.

See: ENetworkFailure

[rose egret]

yea its client without render -nullrhi

I have written client AI that plays the game

🙂

[pallid mesa]

ahh -nullrhi yeah 😄

oh the chaos monkey? that's cool ^-^

[twilit radish]

Chaos monkey?

[rose egret]

w8 I never heard that work

[hollow eagle]

https://en.wikipedia.org/wiki/Chaos_engineering

[rose egret]

im doing that to test the perforamce and gameplay since I dont have 100 coworkers

[pallid mesa]

xD The encysampedia 🤣

[twilit radish]

This is why I'm still sad that one topic on this was on UDN.

But honestly it probably came down to just bots yeah lol.

[torpid girder]

oh i just figured out the reason why data isnt being replicated its because its because its being executed on the client

[rose egret]

im using StateTree for my AI btw, its new without any doc but I like it

[torpid girder]

will a dedicated server execute BeginPlay on a player controller?

[rose egret]

though my client side path finding has little problems

@torpid girder yea

[fossil spoke]

BeginPlay is called in all network contexts

[torpid girder]

that is what i thought

[twilit radish]

except when your base class forgets to call the super

[torpid girder]

    if (GetWorld()->GetNetMode() == ENetMode::NM_DedicatedServer)
    {
        Request->SetHeader(TEXT("User-Agent"), TEXT("X-OnlineServices-Server-Agent"));
    }
    else
    {
        Request->SetHeader(TEXT("User-Agent"), TEXT("X-OnlineServices-Client-Agent"));
    }

[rose egret]

can be summarized in one line btw

[torpid girder]

should i use this to test if code is executing on the server over if (!HasAuthority()) ?

[fossil spoke]

What if you want a Listen Server to execute it?

[torpid girder]

I dont

[rose egret]

HasAuthority means == standalone , listen server or ded

[fossil spoke]

You should look at what HasAuthority is doing.

[twilit radish]

GetNetMode() < NM_Client all the way for those kind of checks.

And then IsNetMode(NM_ListenServer) or whatever for specific stuff.

[twilit radish]

This is not completely true btw. And generally why I don't like HasAuthority(), client side spawned objects return true for HasAuthority().

[blazing spruce]

Hi, im having an issue with getting this timer started, if I put it on begin play it returns false, unless i put a small delay before it which will then go true and start the timer but I know putting a delay there isn't a fix, any ideas how I can have this timer called only for the locally controlled player properly?

My theory is that when i spawn the BP_Caretaker class in the GM, the begin play's firing before its possessed or something causing it to go false

[twilit radish]

If this is a listen server, then yes. That's exactly what happens, which you can easily verify by printing a message indicating which event runs first by overriding the OnPossessed event or whatever it's called in BP 😄

[fossil spoke]

OnPossessed is only called for the Server.

[blazing spruce]

Yeah i tried putting it in there too but didnt work, i need it to run on client i believe

[peak sentinel]

I'm interested to hear why you preferred this - do you hate AIControllers a lot?

[blazing spruce]

only the BP_Caretaker class should see it

[fossil spoke]

@blazing spruce Do you have C++ access?

[blazing spruce]

The whole character class is setup in BP, but i dont mind using C++ if theres no other way lol

[fossil spoke]

You have a few options in Blueprint only.

For Clients its best to wait till the PlayerState exists.

This is an alternative.

Unless you want to properly expose the PawnClientRestart to Blueprint from C++

[twilit radish]

I mean, ideally you also take network performance into account. Which you don't get with typical AI.

[fossil spoke]

This is my recommendation, but if you want to stay in BP only then the above image should cover you.

After it you would check for Locally Controlled etc

[peak sentinel]

You dont get with other tools too

They said they use ST

[twilit radish]

@fossil spoke There's a BP event for that called ReceiveRestarted

See APawn::DispatchRestart

[fossil spoke]

Im guessing that got added in 5?

Im still on 4.27

🙂

[twilit radish]

Give me a second to check where they added that. But could very well be the case.

[blazing spruce]

Interesting that is overridable on the character class

[twilit radish]

Yeah.. UE 5.

[blazing spruce]

so i could use that?

[fossil spoke]

@blazing spruce Use ReceiveRestarted then

If you are on 5

[blazing spruce]

nice! ill give it a go, thanks!

[fossil spoke]

👍

[noble sentinel]

My multiplayer system works when I play it in editor standalone mode 2 clients

but I cant play it with my friends nor I with 2 clients

Its using steam online subsystem with spacewar settings

[twilit radish]

Thought you meant something else, my bad 😛

As in "why don't you just use regular AI instead of clients"

[peak sentinel]

Thats why I asked though 😄

[twilit radish]

(╯°□°)╯︵ ┻━┻

[peak sentinel]

APawn still provides a way to do netcode

[twilit radish]

Yeah but that does not nearly simulate the same performance as actual clients that send over network data etc.

Maybe CPU wise, but definitely not network wise.

[peak sentinel]

In the context you are speaking of it would be just a matter of having client or authority role

And having a "client" AI is more costly

[twilit radish]

An actual client has packet drops that need to be resend, sends healthchecks, has actors that become relevant / irrelevant etc. all while also interacting with the world which in return sends stuff over the network. If you just simulate that with server side AI you don't get any of that.

[peak sentinel]

I think you misunderstood me at first place

Generally in other engines and many games AI "logic" is not a part of the netcode either, and to replicate some necessary behaviors to clients you can still use APawn, so I couldnt see the reason why would completely ignoring server-side AI and using a fake client based AI be an option

So it was a question regarding to curiosity

Made me thought they have a custom architecture or something else, no idea

Since having a client AI is more disadvantage and an advantage in many cases

[twilit radish]

I assumed the idea was to have clients that run AI like code to mimic players actually doing stuff in the world to test server/network performance.

Not yours, but the person creating it.

[peak sentinel]

Ah I see, yeah I can see your point now

I'd like to see that AI though 😄

[twilit radish]

It's on my imaginary todo list as well for some day as it is an absolute pain to test performance properly. But I don't have the server space for it 🥲

Also Battlefield V did it too btw 😄

[peak sentinel]

You might want to provide more info

[twilit radish]

https://www.youtube.com/watch?v=s1JOSbUR6KE

[peak sentinel]

I remember that!

though I didnt watch

[twilit radish]

It's a bit generic tbh. But they explained how they used bots to test performance, used it for QA purposes as there was no way they could cover 64 man games with their QA team at all times etc.

But overall not disappointed I watched it.

[fossil spoke]

@low helm Again, it all depends on your game, you need to pick a number and target that.

Every game is different, every game is designed and architected differently, that all contributes to what level of performance they can manage.

You need to pick a number from the beginning and say "We want to be able to support X number of Players, how do we design and build the game to facilitate that."

[low helm]

I wonder if there are any good examples of Listen Server games that have shipped with player counts above 4

[fossil spoke]

Probably, but just because someone else has doesnt mean you should, or that it fits your game.

[low helm]

Valheim is 10, L4D and DRG and Vermintide all do 4

Well my use case is mostly standard shooter, CMC and AI are our biggest costs, and nothing there is really unusual

So comparing myself to others seems fairly appropriate

[fossil spoke]

If your game is a large world combined arms combat FPS like Squad or HLL, its not going to do well as a Listen Server experience.

Your target audience is going to have wildly different hardware and network capabilities and all of that plays into a Listen Servers experience for all users connected to it.

[low helm]

right

[fossil spoke]

That is typically why you see low Player counts for Listen Server games.

You cannot hope for the best scenario, you have to expect players to be running on a potato.

[low helm]

Yeah so some players could handle 12-16 connections but some run the game on toasters

[fossil spoke]

Exactly.

[low helm]

Ok cool I think I'm starting to get a better picture of what to expect. I just want to have a hypothesis before I begin testing....like Listen servers probably handle 4-6 players on bad hardware, twice that on good hardware, and twice that on Dedicated Server

And see if that hypothesis bears out

Sometimes I join a DRG server that performs really badly with just 4 players

[fossil spoke]

You HAVE to have a target before you build the game. It just doesnt work the other way around, you will simply end up making a game that doesnt work for the performance you end up with if you decide about what number of Players you want to support after the fact.

[noble sentinel]

When I start 2 editors and open the game as standalone, one can join another

but it dont work after packaging project

Like I cant start 2 game instances and make it work

[fossil spoke]

You also have to be realistic about what you can acomplish.

No point saying "We are going to make a 120 Pop Battleroyale experience" if you dont have the talent, experience or expertise to actually do that.

[low helm]

Don't worry I tried to remake WoW 6 years ago

Learned that one the hard way

But it was fun

[fossil spoke]

Everyone in their early days in this industry has had those lofty goals

And 99% come to the realization that its just not how it works.

Look at it this way, if it was easy, everyone would be doing it.

But how many WoW clones exist that were made by tiny ass teams with no experience?

Being realistic gives you a CHANCE at being successful.

[low helm]

Yeah and these days cloning WoW isn't enough anyway

Even if you could

I want just enough people in my game so that artillery coming from a rear guard makes sense, so yeah I'll probably be working towards 16 or 24 players

[fossil spoke]

Thing is, you need to incorporate realistic expectations into your design goals and outcomes.

If you want that as an ingame experience, 1 player shooting a single artillery cannon might not be enough to sell it.

So adjust your design goals.

Instead maybe they command a group of cannons ?

It is a game after all, you can bend reality.

[low helm]

Yeah the players in the rear guard manage cannons and supporting reusable rockets

[fossil spoke]

Bending reality is usually because you are sticking within your lane of competency.

[low helm]

yeah that makes sense

So yeah it's not just 1 player with 1 cannon

It's more like you manage a miniature base

Which provides combat support

[fossil spoke]

Whatever the case is, be realistic about your goals, about your time scale, about what you can achieve. All of this will inform your design and the final product. If done right, you have a chance at success instead of no chance at all.

[low helm]

Artillerymen get this little grid camera and dial in each artillery peice manually, no pings

Yeah cutting scope has been a multi-year project for me

To get down to somethign realistic

Where the circles indicate target and radius

[fossil spoke]

Cool, we are drifting a bit offtopic though.

[low helm]

True, I really appreciate the conversation

[fossil spoke]

I hope this was helpful.

[low helm]

Paypal is ready 🙂

[fossil spoke]

You dont owe me anything. Only that you heed the advice 🙂

[digital pendant]

is anyone in here familiar with AWS?

specifically gamelift

[opal pulsar]

Is there a way to make a function as only able to run on the server? Not a server RPC or HasAuthority, im curious of any specifiers or anything, I read about one but cannot find it, maybe it was an older unreal thing? I just want to ensure a client cant call a function an if (HasAuthority) seems hacky using it everywhere

[fossil spoke]

@digital pendant Whats the question?

[fossil spoke]

Its not hacky to use something for its intended purpose.

BlueprintAuthorityOnly will cause any nodes with this specifier to not be executed on Clients.

[digital pendant]

im not sure if you will be able to help, but I have an older project that I am coming back to and one of my endpoints seems to not be getting called.. when my game ends it will pick a winner but it seems that the endpoint execution is getting skipped.

[fossil spoke]

Not sure what you mean exactly? The HTTP request isnt being sent?

[red pollen]

If there are any GAS gods hanging about, please check my post in #enhanced-input-system
Ty! ❤️

[digital pendant]

either its not being sent or its sent with the wrong authorization and gets ignored.. trying to look into that right now.. it may be something as simple as wrong password

[fossil spoke]

You should be able to view incoming requests on the API Gateway.

[digital pendant]

i have another lambda function that verifies that this message comes from the game server so it might be failing that check

nothing shows up in cloud watch, I am unsure where to look for api gateway

[noble sentinel]

Can anybody check this

Im still trying it but stuck...

[digital pendant]

unless you have the clients connecting to a dedicated server it wont work, unreal will spin up a dedicated server in the background and connect the clients to it

or do you have it setup as P2P

[noble sentinel]

I have an host server bp when someone press host server button

and others are connecting with ip

Im sending the photos of it in a sec

When somebody click host server it open loading level with listen

then,

this in level blueprint happens,

[digital pendant]

you arent creating a session

[noble sentinel]

and it opens first level

[digital pendant]

ah ok

[noble sentinel]

where is problem can be?

[digital pendant]

Im not exactly sure, i dont have experience with P2P, but I found this which is similar to what you are doing

https://youtu.be/dQD_sPFXcBg?t=527

[noble sentinel]

should this listen be ?listen or smth?(nope it s true as video shows it like this)

That dude in video make it like me

with few differences, Im checking it

its session create is a bit different from mine

[digital pendant]

Yes, it seems he has the functions set up a little differently. maybe follow him

[noble sentinel]

Im using advanced steam session

he is using another thing I think

[digital pendant]

maybe if you watch his set up you can figure out whats going wrong, i dont think it matters much advanced vs regular session node

[noble sentinel]

thank you, I think this is the problem, I should use find session instead of open level for joining

Thank you for help

[digital pendant]

🙂

[deep coral]

how do you check for game package number/version for preventing multiplayer joining of different game versions?

[misty stirrup]

does anyone have any info on having a user cross a threshhold and getting passed to another dedicated server?

like load balancing the actors data between two servers? ive seen it done for minecraft w/ zeromq

[opal pulsar]

Is it completely valid to call game mode functions from a server spawned actor if its guarded with a HasAuth()? I'm struggling otherwise to see how a non locally owned actor can call and send info to the server

example

void AProjectile::OnOverlap(blahblahinfo)
{
  if (HasAuthority())
  {
    foo* ptr = GetWorld()->GetAuthGameMode<foo>();
    ptr->HurtActor(bkahbhlahinfo)
  }
}

[low helm]

There are third party tools to help with multi-server setups, SpatialOS was one of them but I'm not sure if they still exist.....they're based in Ukraine I think

I once wrote a super simple version of this in Blueprints though, where walking into a portal in World A connected you to World B on another server, the address of which I could plug in on the server side of World A

But this wouldn't include any information sharing between servers, like WoW had where servers would share duplicated copies of actors on the margin between 2 servers

[misty stirrup]

what really throws me off is like... how should i share the memory?

like

when i share the player location to the second server, should i just give it the vector location

or am i thinking about it wrong; is it about the player input and the current location of the actor

[vagrant grail]

Does anyone know why when I set the number of players to 2 (to have 2 windows open) or more we can't see each other's character ?

Ping me if any answeer please 🙂

[upbeat basin]

Are you changing your play mode as well?

[vagrant grail]

thanks

[upbeat basin]

If I get your question correctly (and if I'm not wrong) you can't send information (calling RPC) to the server by using an actor that you don't own, as a client. You need to use one of the actors that you own (PlayerController, PlayerState, Character etc.) to send a server RPC and handle your logic there

[thin stratus]

@opal pulsar @upbeat basin since the overlap usually happens on everyone who has an instance of an actor, you are totally free to just limit the code to authority. The rpc part that Layso wrote is true though

[deep coral]

If I execute console command "servertravel somemap" in a multiplayer game, will the new level still be listening (ie, other players can still join)

[thin stratus]

Yes

[deep coral]

how do I stop the listening, so only the lobby players are the ones who can join?

[thin stratus]

You can't stop the listening itself. But you could update your session to not be advertised and joinable anymore.

Or if it's not about sessions you could kick the player when PostLogin calls and you aren't expecting them.

You can also pass ?MaxPlayers=
Along with your server travel and behind the = you pass in the number of lobby players, then other players would be denied due to server being full.

Ultimately I would solve this with keeping track of all the UniqueNetIds that were present in the lobby and then using PreLogin or Login to check if someone is allowed, otherwise return an ErrorMessage.

But PreLogin and Login require C++.

And the Session updating requires either C++ or a Plugin.

If you only do BPs, then your best bet is the MaxPlayers setting and/or handling new players in PostLogin in your GameMode. Not sure what you can use in Blueprints to identify them though

@deep coral

[deep coral]

gotcha

[noble sentinel]

really, what did you do to solve this?

Im trying to fix this rn

Also, this should be work right? I dont know if the problem is my bp

[torpid girder]

hello, i am back trying to understand why I don't see my player controller log message being printed in the dedicated server output. I see the player connect in, however before i tried connecting to a dedicated server i could always see the beginplay being called

[winged badger]

GameSession class has IsAllowedToLogin or some such, called from PreLogin in GameMode, not sure if its blueptint native though

[thin stratus]

GameSession class as a hole is not a BP thing

At least not to my knowledge

[winged badger]

Probably, not near PC to check

[torpid girder]

just need to check, if i run "C:<YOUR INSTALL PATH>\Engine\Binaries\Win64\UnrealEditor.exe" "A:\MyProject\MyProject.uproject" -server -log what build is it running? it doesn't appear to be the development server

i put lots of debug log lines in and they don't appear

that sounds correct, unless you set a way to replicate then it won't

[hollow swallow]

Would anyone know why all the clients can move fine, but the host cant? cant even look around, they can still see everyone else moving though

[torpid girder]

that is probably way too difficult for someone to answer, i would suggest looking into the movement code

[hollow swallow]

Only using the third person example one. Was following kekdots multiplayer tutorial

[torpid girder]

i don't know that tutorial

i am trying to figure out which build of my code "C:<YOUR INSTALL PATH>\Engine\Binaries\Win64\UnrealEditor.exe" "A:\MyProject\MyProject.uproject" -server -log executes, because its not the development build as i thought, i've almost tried all

[hollow swallow]

no worries. How can i call something only on the host and not the client?

[short arrow]

Has authority node, or rpc call through an event

[twilit radish]

@torpid girder It certainly does execute "Development Server"

Try actually switching over your build target in VS in the top left instead of whatever "Quick build" may be.

[torpid girder]

right i've changed some log lines from error to warning, they should reflect if i quick build

ah, so i can't run a server and client on the same machine

i just saw i was breaking things

[twilit radish]

You definitely can unless you enabled something specific that disallows it. I just did it when I took that screenshot.

[torpid girder]

when i ran the server, it hooked into VS and i was able to hot reload it

not sure why it hooked in this time

sigh and i am still running the old binary

[torpid girder]

ah this is interesting, if you run "C:<YOUR INSTALL PATH>\Engine\Binaries\Win64\UnrealEditor.exe" "A:\MyProject\MyProject.uproject" -server -log from the project directory it connects to visual studio

[green fjord]

hey can i change the speed of packets sent between client-server for the movement replication?

[wooden abyss]

Hello, I have a question regarding rewards for players. In my TD game I have an event in my Gamemode thats called "RewardOnEnemyKill" which should give a base reward like gold to every player in the game. Each player has their own multipliers for gold gain based on a skill tree. Now I'm wondering where I should add this bonus to the reward. Should I add this "reward logic" to my Gamemode Event which just gets the bonus from the PlayerState? Or should I add this logic to the PlayerState and add a function AddReward that calculates the actual reward inside the PlayerState. But that would be some kind of reward logic and I'm not sure if I should keep this logic inside a PlayerState cause it should just be a data class. Does anyone have any tips or best practices for this?

[potent coral]

i just used null subsystem to make p2p connection

[green fjord]

hey can anyone explain me what is the different between MaxNetTickRate,
NetServerMaxTickRate,
LanServerMaxTickRate,
NetClientTickPerSecond,
MaxClientRate, and
MaxInternetClientRate

when i call rpc unreliable on event tick, does it will follow the tickrate speed or follow the game FPS speed?

[prisma snow]

afaik the network thread runs at a different frequency than the game thread so it is not guaranteed that calling an rpc on tick results in the rpcs actually being sent evenly at the same rate. But I'm not sure so better if somebody more knowledgeable confirms it

[twilit radish]

I'm going to be honest, the net tick rate limit code is the most confusing thing I've seen all day 🤣

I know for sure that dedicated servers tick at the speed of: NetServerMaxTickRate
But I can not figure out for over 30 minutes now already what exactly limits or does not limit clients and also listen servers.

[scenic turtle]

Hey all, I would like to know what would be the best way to handle a client - dedicated server scenario
-Client downloads chosen character through Chunkdownloader and sets it as its pawn
-Another client downloads a different character through chunkdownloader
-They both join the dedicated server

• Will they be able to see each other characters on the server map?
• I think, not, and i would have to have something on the server that send some asset/ chunk ID to the connected users and they would download the other users missing character..
  -Or i am over complicating things?

[twilit radish]

Are you referring with "pawn" to an entire pawn class/blueprint or similar or a dynamically downloaded mesh? Big difference there.

[scenic turtle]

Mesh sorry

Well.. I mean pawn would be more ideal, as they are currently in their own separate blueprints, but if mesh is easier than probably i would go down that route

[twilit radish]

Both clients will need to download both meshes, Unreal does not replicate entire dynamic downloaded meshes and thus the clients don't know what to load otherwise. So yes, you'll need to let the server know "Hey, I'm using mesh X" then the server accepts that (or denies if not owned or whatever?) and lets the other client know "Player Y is using mesh X! Go download that mesh and apply it afterwards."

If you want to use completely dynamic pawns the server now also needs to download them as it has to spawn the actual pawns.

[twilit radish]

Also do note that your collision should not be different with this per mesh otherwise the server still needs to download it just for the collision because you don't want clients running around with different collision on the server vs client. But that depends on what you exactly did I suppose.

[scenic turtle]

The server will be packaged with all the list of possible pawns, and they should have the same collision as they are all technically the same characters with different meshes

But yeah, sadly i am not really expert on the topic and I only recently started to use ChunkDownloader

[twilit radish]

I don't really see why you're dynamically downloading meshes then though? Unless you have a set of certain pawns that can have an infinite amount of different meshes created by others or something?

Or is it something like DLC content?

[scenic turtle]

Hmm something like that Thom, because the idea is that after user logged in, they will receive a chunkID and based on that ID they download their character through ChunkDownloader. Then they join the Servermap, server will know about all these characters. But I am wondering how another client who will join the server with character model A will know about the other user's character model B vice versa.

Sorry if my explanation is not clear.

[twilit radish]

If you set a replicated variable on the server side pawn with which mesh was selected by the corresponding client then a new joining client will receive that and can also start loading the mesh.

[scenic turtle]

Can you please explain what do you mean by server side pawn?

[twilit radish]

As in the pawn that exists on the dedicated server.

[scenic turtle]

And if I would try to download different pawns? Would that be a completely different topic? Thanks for your help so far.

[twilit radish]

I must say that goes beyond me, I don’t know if the server can properly replicate a pawn that the client needs to still download.

Maybe by spawning it locally and trying to make it net addressable, but not sure honestly.

[kindred widget]

Are these majorly differing pawns, or are we talking cosmetic modifications like Fortnite skins?

[scenic turtle]

We can say like Fortnite skins.

[scenic turtle]

Right, much appreciated for your input anyway.

[kindred widget]

Would strongly recommend not doing anything outside of Unreal's normal networking. Lyra does this at least by replicating Character Parts through a fast array.

[twilit radish]

Creates own network protocol with custom dedicated server written in NodeJS >:D

[scenic turtle]

Right, cheers Authaer i wil check out that sample project, in the end I will probably stick to just replacing meshes then. That seems like a more stable approach.

[kindred widget]

If memory serves, they just do a FastArray, and each one contains a pointer to a ChildActorComponent. I know the stigma around them, but it's actually a pretty decent approach. Even the character's Manny/Quinn mesh is one of these.

[twilit radish]

The last time I used child actors my project didn't work in a packaged build any more lol.

[kindred widget]

I mean to be fair you can do the same thing yourself with normal attached actors. But I assume if they're using it in Lyra, possibly in Fortnite, they've probably fixed some bugs on them.

[twilit radish]

Could be, this was back in 4.26 or so I think.

So it has definitely been a while 😄

Cedric is about to either ask the most complicated question of the day or about to correct someone who was wrong 😂

[thin stratus]

Has anyone solved a setup like this before?

A "main" Character that is representing a Player, so if it dies it would count as actual Death (Score wise).
And a "remote-controlled" Character that the Player can temporarily control while the main Character stands still.

And handling that main Character being affected by things and even dying while controlling a different Character.
The issue is that I need to possess the other Character, but I still need the main Character to be handled as being controlled.

If I don't do anything, then the main Character will be unpossessed, and possibly counting as SimulatedProxy for the Player (even locally).

wow Thom, wow

Hope you can answer this for being such a nice person

[twilit radish]

It was not meant to be rude, sorry if that come over like that 😅

[thin stratus]

All good :P

I struggle with this, cause I have GameplayAbilities that are set to predict to execute locally first.
But if the main Character is not possessed then those will fail the NetRole check.

I could possess it with an AIController in the meantime, then it would probably execute the GameplayAbility on the Server.

But then it would nuke the Controller and PlayerState pointers

And killing it would not count as a Death to that Player anymore

[twilit radish]

What exactly would be the problem with temporarily nuking the pointers though? Worst case you just keep a weak reference to the appropriate controller I guess. But trying to truly posses two pawns at once seems like a nightmare.

Could just implement a getter for both the player state and controller that first checks if there's no 'override' and otherwise just grabs the actual owner etc.

A random other thought would be to perhaps spawn two player controllers with the same owner? I don't know how well that works, but in theory it's pretty much what splitscreen does.

[kindred widget]

Wonder if you could override the player pawn's Unpossessed, and not change ownership or controller, or playerstate? Wondering what would happen if you just left those as is while possessing the other pawn. Have not tried.

[twilit radish]

Why I didn't want to suggest that is because there are internal references to both from each other, player controller references pawn while vice versa is also the case. Then you need to also fix up those links which I'm not sure is as great either.

[thin stratus]

I'm also a bit hesitant on those wrapper getters cause we already have a big project with tons of calls to the native getcontroller/getplayerstate functions

[oak oracle]

hey devs , asap question , i got float variable and passing it trough Client RPC but when rpc runs passed value is got reset , as you can see on scneeshots before to send in to the RPC its 130 but after it reached RPC its 0 , any ideas why ?

[thin stratus]

Can you progress one step further so the break is on the cast node and see if the float value changes?

Also you are calling a CLIENT RPC on the GameState

That will not work

GameState can only process MULTICAST RPCs and only on the Server (by definition of Multicasts)

CLIENT RPCs require the Actor to be owned by a specific Client

Which GameState is not

[oak oracle]

oh okay , by the way are u the guy who wrote Network Compedium ?

[thin stratus]

Yes

[oak oracle]

wow, it teached me a lot , awesome article 👍🏻

[thin stratus]

(: glad it helped

[twilit radish]

You can override the PreLogin in gamemode if you just want to print it or something, but I don't see any exposed BP functions that allow you to access it.

[wooden abyss]

Hello, if I'm trying to handle rewards for players in a multiplayer game in the Gamemode BP by giving every player a base reward, but that reward gets multiplied by an individual multiplier for each player, should I do the multiplication inside the Gamemode as well? Or should I do that in the PlayerState where I have the actual currency variable and the multiplier?

Like this...
Calculating the actual reward in the Gamemode and only saving/adding the correct value to PlayerState

Or maby like this...
Calling a function from PlayerState that takes in the base value and calculates/saves on its own

Second option would have "logic" in the PlayerState. Not sure if thats ok or if i should just keep this in the Gamemode

[kindred widget]

It's odd that each player gets a different multiplier.

But generally speaking I would keep all of this in the game mode. Should be part of the calculate function.

[spark igloo]

Hi guys,

I have been working on Linux dedicated server size optimization but I tried to exclude debug files and pakbaklist to remove unsed content gng into server build. But still the generated build is 120MB. How can I reduce it ? Engine Binary files are taking about 110 MB how can I optimize the memory here

[wooden abyss]

It's gonna be a coop game where each player has its own level and skilltree independent from the current match that is being played. This will give bonuses to the currency gained as well. That is why they will have different multipliers depending on their skill tree

Alright I will try to keep it inside the Gamemode then. Thanks for your input @kindred widget

[real ridge]

Guys I have one question i have stored values here in player state when I open my game etc but when I join session all these things are getting like removed and I dont have it there anymore how I can restore them?after joining session

and I cant use seamless travel as it is just joining session from online menu not from server to server

I have easy login where I put for example Kamil Kamil it will log me save name there + team etc and then I hit play it will join session and its empty

[wooden abyss]

If you dont use seamless travel your playerstate is lost between levels i think

You could use the GameInstance to save whatever you need to persist between level changes

[real ridge]

i cant use seamless travel because its not moving between levels I am on server after joining session not before

Login (offline)->Menu(offline)-Here is data lost->play(online)

[wooden abyss]

Well then you can still use the GameInstance to store the info you need and then read them whenever you have that transition

[real ridge]

I am doing login via varest

[real ridge]

but cant that player hack in multiplayer game somehow?

and change it

[wooden abyss]

As the GameInstance exists for each client: yes they could

[real ridge]

so then I cant make it like this 😦 I cant store anything in game instance

[twilit radish]

If you're going to store data like teams on the client side then you should change your approach regardless if you care about cheaters.

[real ridge]

its there because in player state id didnt persist

anyways client have also access to player state

so how then

[twilit radish]

Having access to some data versus being able to store that data on the client and expect it to be used again is a totally different story. If you don't want clients to be able to cheat you will want to keep the data on the server. You can for example get their unique id and store data along with that in the server game instance or as a file somewhere to persist throughout game restarts.

[real ridge]

so if I store something in player state? then me as player cant access it ? because I can access it from server and client too

then what is game instance good for

if i take case that client can cast to playerstate then also can hack it

[twilit radish]

The player state is shared across all clients correct. The game instance was an example as it persists throughout the entire lifecycle of a game, if you change the level it still exists.

[real ridge]

i know

but then its not usable for MP

• also if I just store value in player state and have variable lets say TEAM there and dont multicast it then its stored only locally for client not for server than obviously I can hack it no?

[twilit radish]

But what's the point of storing a team locally in the player state if you're not doing anything with it on the server? Also you can very much use the game instance in multiplayer, just because it can't make network calls it self doesn't mean it's not useful and again it was an example as you were asking for ways to store data for longer than a single level.

[real ridge]

sorry if I am talking shits just want clarify it

[real ridge]

ik i can use game instance I just want use it in right way and store there informations which can players change seems not okay same like store damage which can cause player in his blueprint propably not right

so all things which I want to be not editable by player should be stored in player state yea?

also then what if I have pawn which is AI and it has variables these should be in playerstate too? but it doesnt have playerstate as its only AI pawn

[twilit radish]

That's not what I'm saying whatsoever. Like I said, if you want something to be away from the client you should keep it server side. You can share the data with them through the player state, that's completely fine. But don't store the data on the clients side and then have them later on send that to the server as that will allow for cheats. You would instead persist that data on the server through 'something' capable of doing that and then when needed use that data that the server stored again so it doesn't have to come from the client.

The golden rule in terms of cheating is very simple:
If a client can send over the data then that specific data can be manipulated by someone. Don't ever just assume it's safe. Unreal does do some validation with certain stuff already, but by far not everything.

[real ridge]

okay and my last question

How I know client cant access player state variables and change it

IF

I have stored things there

and I am for example not multicasting their storage

[twilit radish]

It can't. A client can not magically change variables in the player state on the server. It will have to make a request to the server with "I want to change this data" which can only be done if either Unreal provides a way for it or if you make a way your self. If you do provide a way and don't properly deal with that request or can't properly deal with it then it becomes an issue.

[real ridge]

also if I understand right till variable is not set replicated server doesnt know about it,/not sure if I have also use set via multicast to store it on server

[twilit radish]

A multicast can only be called from the server. So at that point you're already on the server.

[real ridge]

ok lets say RPC

hm I have mess in it

in singleplayer games you also have playerstate but there is no server it means then there you can hack those data?

[twilit radish]

You can't possibly protect data in singleplayer, correct.

[real ridge]

and thats why I dont understand it ahhh

😄

[twilit radish]

Singleplayer games happen on someone's device, you do not control that device. If someone wants to do something to their game they can do so because nothing stops them from doing so.

[latent heart]

Unless it's like stadia and played remotely. Do not be stadia.

[twilit radish]

And that's exactly why cheats exist in multiplayer games, you do not control the device people play on. If you make a RPC from client -> server that allows someone to change their nickname as an example then they could in theory change their name to whatever they want it to be because they own the device where that data comes from. A regular user won't do this, but a cheater could if they wanted to.

That's why like I said you keep data on the server that you don't want clients to be able to change. They can't magically manipulate server side data.

[real ridge]

but imagine my situation till I Join session (arena) my game is offline and all things are in player state /stored then I want persist that data to my session yes? but if you saying in singleplayer I can change data then someone before joining game can change his TEAM or name in player state (possibly hack game) and after joining game he will have another name + team
SO how to protect from this?

[twilit radish]

You don't. The moment it's offline they can do everything to it they want to. You can't expect that data to not be changed if a cheater wants to.

[wheat niche]

hey, i implemented multiplayer and i want to simply send a message to all players OnLoginPost. The problem is that it gets only called server side i created a custom event that is replicated multicast and then print something but i just prints for the server does anyone have an idea how to solve it

[dawn ledge]

You have to multicast from an actor that is replicated to clients

[twilit radish]

Are you doing this from within the game mode or calling it somewhere else? The game mode has no network capacity it self.

[real ridge]

so then there is no way how to protect from cheaters well...

i am lost

[wheat niche]

so what i did is i added the OnPostLogin event inside my gamemode and then i created a multicast function inside my gamestate is that correct=

?

[twilit radish]

If you expect to import data from single player then there's indeed no way to prevent cheaters. @real ridge

[hushed heart]

Hello! Apologies for interrupting, I have what's likely a bit of a scrubby question, but hopefully quite quick to answer. I know that OnRep functions will let clients know when one of my properties is replicated down to them. Is there way to get an OnRep for transform-related stuff? Like an OnRep for my clients when they receive a new actor location?

[latent heart]

The only way is to heavily validate imported data.

[real ridge]

its my only way because all my login, lobby stuff works on websockets and varest

so till i join session

i am "offline"

[latent heart]

E.g. you check if osmebody says they have 2000000 rounds for their pistol, you ban them.

[twilit radish]

That still allows cheats, you can't guess how that data should be valid or not. You can validate it to the point in a state you expect it to be, but you can never fully make it cheat proof 🙂

[real ridge]

this is too hard theme

hah

but thanks for talk

I am more confused as I was

:DDDDDDDDDDDDDDDDD

[twilit radish]

@real ridge TL;DR there's no way to prevent people from changing data that comes from a singleplayer/offline mode and is then sent to a server.

There just simply isn't a solution to that.

If you want it to be cheat proof, don't send the data from the client to the server, if that's not an option then you'll have to live with that being an option to cheat.

[latent heart]

Aye. Sadly!

[latent heart]

Well banning is probably a bit ott. Mistakes can happen with data.

[twilit radish]

Which is exactly my point, you can't know what is valid data or not. Maybe a new player has 500 coins to name an example, but perhaps someone that played the game for years has 50.000.000 coins mean while. If you "guess" it could only have been 20.000.000 and ban them for it then you're getting rid of innocent players which is why it's just really bad to do that.

Also speaking of security stuff, does anyone know if Unreal checks for NaN/infinite floats/doubles?

I'm kind of guessing it doesn't right?

[latent heart]

It does in dev, not in shipping, I think.

[twilit radish]

🤔

[latent heart]

It's checked in TVector somewhere, I think, if you want to check the conditions.

[twilit radish]

Thanks, will take a look in a bit 👍

[lost inlet]

https://docs.unrealengine.com/4.27/en-US/API/Runtime/Core/Math/FVector/ContainsNaN/

I would doubt there's any implicit checking for NaN/inf for RPCs/replicated values

[latent heart]

There's checking when it converts between types. vector to rotator etc

#if ENABLE_NAN_DIAGNOSTIC || (DO_CHECK && !UE_BUILD_SHIPPING) with these conditions

And when those types are assigned/created

It's basically everywhere.

[twilit radish]

That one feels to be more related to debugging though.

[frank birch]

Where should I create my widgets? I wired myself to the begin play of a custom HUD class but I am getting an error that Blueprint Runtime Error: "Accessed None trying to read property CallFunc_Create_ReturnValue". Node: Add to Player Screen Graph: EventGraph Function: Execute Ubergraph HUD Ready System Blueprint: HUD_ReadySystem (only happening on dedicated server, listen server doesn't error)

Where should I create my widget and append to screen? 🤔

[gloomy tiger]

Yeah that's happening b/c dedicated servers don't have widgets iirc

[frank birch]

but they do have HUDs? 🙃

[gloomy tiger]

I guess so.

I don't remember exactly, tho

What you can do is checking if it is locally controlled

A lazy solution though

[frank birch]

Yeeeep, dedicated server has a HUD 🙃
well, locally controlled should be okay 🤞

[gloomy tiger]

Even though the HUD is named, well, HUD, it's still an Actor, you know. I mean, you may find some utility on replicating stuff there. (Never was the case for me I may point out)

[frank birch]

server is returning true 🙃

[gloomy tiger]

server as in dedicated or listen

[frank birch]

dedicated

[gloomy tiger]

When you say 'dedicated', what exactly are you talking about?

[twilit radish]

That's not a dedicated server if you can see the message.

[gloomy tiger]

Yes

If this is what your NetMode looks like, you're not running on a dedicated server

[gloomy tiger]

✨

That's not dedicated.

[frank birch]

ohhhh 🤔

[twilit radish]

Honestly "as client" is confusing as heck because it does run a dedicated server if you go standalone.

[gloomy tiger]

(Though I see no other way to do that lol)

(I mean, not the naming thing, but not spawning a dedicated server when two instances are clients)

[twilit radish]

You can launch a dedicated server through the command line from the uproject.

Oh like that. Well sure, but that it's different when not running standalone is weird.

[gloomy tiger]

100%

[frank birch]

ok, but then what can I use to ask "does this thing has a screen?" 🤔

[gloomy tiger]

Though isn't this "dedicated server" lifted by standalone game a listen server simulation?

[gloomy tiger]

Now we gotta step back a little I guess

[gloomy tiger]

Because this got invalidated

[twilit radish]

If you can see the message being printed it's a listen server because dedicated would not show that message as far as I know as it needs to be a separate process.

But I'm not 100% sure, but it makes absolutely no sense to not be a listen server.

😄

[gloomy tiger]

IsLocalPlayerController && !IsServer maybe lol?

[gloomy tiger]

That in case you want to simulate a dedicated server

[twilit radish]

You don't want to ignore the listen server though because then that one has no UI.

[gloomy tiger]

What's weird though - is your HUD marked as Replicates?

[gloomy tiger]

I guess he was developing it as if it was a dedicated server so it does not matter

[frank birch]

hud never replicates, it can't. 300% sure of that

[gloomy tiger]

Ideally though - if you're aiming a dedicated server, you should setup things right

[gloomy tiger]

Yes that's what I expected but you can make it replicate since it's an Actor afaik

[twilit radish]

That's why this makes no sense in the first place because HUDs indeed don't spawn on dedicated servers. Don't ask me how they spawn on listen servers though as they use GetNetMode() == NM_Client.

[gloomy tiger]

Don't ask me how they spawn on listen servers though as they use GetNetMode() == NM_Client.

Is this legit? 😐

[twilit radish]

https://github.com/EpicGames/UnrealEngine/blob/release/Engine/Source/Runtime/Engine/Private/PlayerController.cpp#L1019-L1022

[gloomy tiger]

If that's legit, unless the server instance is a client itself - which I'm quite sure it's not - I mean, I find myself clueless.

[twilit radish]

The server is not a client, I can pretty much tell you that.

But once again, they weren't running as a dedicated server. That's the whole problem with this.

[gloomy tiger]

That's what I expect otherwise my GetNetMode() == NM_Client would all be broken.

It's controversial then

    if ( GetNetMode() == NM_Client )
    {
        SpawnDefaultHUD();
    }

@frank birch are you spawning a hud yourself?

Or just replacing the default one?

[azure cape]

I got a very weird issue :

I'm overriding OnBecameViewTarget in my character
this character calls a function which, at some point, checks if the player is locally viewed
When the player first becomes the view target, IsLocallyViewed returns true if the player is playing offline or is the host
however, if the player is a client, OnBecameViewTarget gets called twice for some reason, and both times IsLocallyViewed returns false
Checking IsLocallyViewed after that returns the correct value however
IsLocallyControlled is always correct regardless of if it's checked on the host or client though

[frank birch]

oh, you gonna love this
(Play as Listen Server and Play as Standalone returns false, Play as Client returns true 👀 )

[gloomy tiger]

I mean, @twilit radish, this is weird. Because this is broken as well. In "p2p" sessions I'd expect my server PC to have a default HUD.

[frank birch]

nope, just setting it as default in my GM

[gloomy tiger]

I guess we were wrong then 🙂

[thin stratus]

Play as Client is meant to be a Dedicated Server environment.
One can argue that it might not be a separate process, but code and branch and whatever wise this is a dedicated server

And print strings are very much visible in client windows in pie when printing on servers

Even draw debug 3d stuff is visible cause epic multicasts those

[twilit radish]

With a listen server yes. But you can't possibly run a dedicated process inside a client as that's not a dedicated server?

That's just a listen server 🤷‍♀️

[gloomy tiger]

I think the process is at the editor?

Regardless of that

[thin stratus]

Play as Client is not a Listenserver

[gloomy tiger]

.

[frank birch]

But then... why is my "not-so-dedicated-server" spawning a HUD object? 🤔

[gloomy tiger]

Now this is where the real question is lol

[frank birch]

ok, found it 🤦‍♂️

I was creating a local player on my GM 🤦‍♂️

[thin stratus]

Also

For the ListenServer HUD question

The line you looked at with the NetMode

Is not what spawns the HUD for the ListenServer

Not sure if that was clear

[twilit radish]

I was meanwhile also looking at where it could spawn specific for a listen server, but I didn't find anything so far. Where does that happen?

[thin stratus]

void AGameModeBase::GenericPlayerInitialization(AController* C)
{
    APlayerController* PC = Cast<APlayerController>(C);
    if (PC != nullptr)
    {
        InitializeHUDForPlayer(PC);

void AGameModeBase::InitializeHUDForPlayer_Implementation(APlayerController* NewPlayer)
{
    // Tell client what HUD class to use
    NewPlayer->ClientSetHUD(HUDClass);
}

void APlayerController::ClientSetHUD_Implementation(TSubclassOf<AHUD> NewHUDClass)
{
    if ( MyHUD != NULL )
    {

        MyHUD->Destroy();
        MyHUD = NULL;
    }

    FActorSpawnParameters SpawnInfo;
    SpawnInfo.Owner = this;
    SpawnInfo.Instigator = GetInstigator();
    SpawnInfo.ObjectFlags |= RF_Transient;    // We never want to save HUDs into a map

    MyHUD = GetWorld()->SpawnActor<AHUD>(NewHUDClass, SpawnInfo );
}

[twilit radish]

ew

😂

[thin stratus]

That's also the function I usually use to spawn my UMG HUD

Cause BeginPlay can't be reliably used

Also you should have noticed that SpawnDefaultHUD is not the correct function, as that has no idea what Class you selected in the GameMode :P

    /** Spawn a HUD (make sure that PlayerController always has valid HUD, even if ClientSetHUD() hasn't been called */
    virtual void SpawnDefaultHUD();

That's mainly due to HUD having a shit ton of debug draw stuff in it I guess

[twilit radish]

Ok that's definitely my fault for not thinking that through 😂

I was like "spawnactor<Ahud>" - that probably checks out.

[thin stratus]

/** The editor will act as a Client. A server will be started for you behind the scenes to connect to. */
PIE_Client UMETA(DisplayName="Play As Client"),

[frank birch]

why? 🤔

[thin stratus]

Cause it doesn't call if you ServerTravel from Map A to Map B and both use the same PlayerController class

Cause the PlayerController will just persist

[twilit radish]

In my defence Cedric, "suddenly" having ahud supposedly on a dedicated server definitely made me question "as client" lol.

[frank birch]

ohhhh, riiiiight 😰
with AGameMode that instead of "swapping" it somehow survives the old controller, right?

[thin stratus]

Always question the person trying to make you believe the DediServer has a HUD :D

[gloomy tiger]

This is true only if you use seamless travel - which is advised that you use it whenever possible

[twilit radish]

That's exactly what I did. And that's why I thought it wasn't a dedicated server. I did indeed not think of it being a player being spawned inside the game mode 🤣

[thin stratus]

Fair, I forget "Seamless"

[frank birch]

And both PC are the same class
And you are using AGameMode instead of AGameModeBase
(if I understand all I read this week correclty 😅 )

[twilit radish]

Pulls up Wizard's blog

[frank birch]

exactly

[gloomy tiger]

I didn't mean it. I wasn't sure of it. And I let it explicit.

[frank birch]

I am living on eXi's guide and the wizzard blog 😅

[twilit radish]

😄

[thin stratus]

// Standalone requires no server, and ListenServer doesn't require a separate server.
        const bool bNetModeRequiresSeparateServer = NetMode == EPlayNetMode::PIE_Client;
        const bool bLaunchExtraServerAnyways = InRequestParams.EditorPlaySettings->bLaunchSeparateServer;
        const bool bNeedsServer = bNetModeRequiresSeparateServer || bLaunchExtraServerAnyways;

        // If they require a separate server we'll give the EditorEngine a chance to handle any additional prep-work.
        if (bNeedsServer)
        {
            // Allow the engine to cancel the server request if needed.
            FGameInstancePIEResult ServerPreCreateResult = PreCreatePIEServerInstance(
                ErroredBlueprints.Num() > 0, false /*bStartInSpectorMode*/, PIEStartTime, true, PlayInEditorSessionInfo->NumOutstandingPIELogins);
            if (!ServerPreCreateResult.IsSuccess())
            {
                // ToDo: This will skip client creation as well right now. Probably OK though.
                UE_LOG(LogPlayLevel, Warning, TEXT("PlayInEditor Session Server failed Pre-Create and will not be started."));
                return;
            }

            // If they don't want single process we launch the server as a separate process. If they do
            // want single process, it will get handled below as part of client startup.
            if (!bUserWantsSingleProcess)
            {
                const bool bIsDedicatedServer = true;
                const bool bIsHost = true;
                const int32 InstanceIndex = 0;
                LaunchNewProcess(InRequestParams, InstanceIndex, EPlayNetMode::PIE_ListenServer, bIsDedicatedServer);

                PlayInEditorSessionInfo->bServerWasLaunched = true;
            }
        }

[twilit radish]

Sneaky in the background then smh.

[thin stratus]

            // Create the instance. This can end up creating separate processes if needed based on settings.
            // This code is separated out of here so it can be re-used by the Late Join flow.
            CreateNewPlayInEditorInstance(InRequestParams, bRunAsDedicated, LocalNetMode);

[gloomy tiger]

Also

[thin stratus]

        // Fixed tick setting
        if (InRequestParams.EditorPlaySettings->ServerFixedFPS > 0 && bInDedicatedInstance)
        {
            PieWorldContext.PIEFixedTickSeconds = 1.f / (float)InRequestParams.EditorPlaySettings->ServerFixedFPS;
        }

Things you find..

[twilit radish]

Ew.

[gloomy tiger]

The server indeed had a HUD, so sue me. lol

[twilit radish]

But why on earth would you ever expect a dedicated server to have a player?! 🤣

[gloomy tiger]

Not the server itself, but its local instance has a PC.

[twilit radish]

Nothing is ever going to make me even think about that someone may have spawned a player inside the game mode lol.

[thin stratus]

I think they aren't actually starting a Dedicated Server

The Editor is a Dedicated Server

Basically the PIE Session is marked as DedicatedServer and will then skip creating some things

[twilit radish]

Actually.. That makes a lot of sense.

[thin stratus]

And the Client is an additional window, same as if you play as a ListenServer

[twilit radish]

I was running Unreal Insights not too long ago and the editor was also considered part of that after I added the custom launch parameters.

[gloomy tiger]

rings

[gloomy tiger]

But where does come that from?

[twilit radish]

Wdym?

[gloomy tiger]

🤔 who is doing that?

[twilit radish]

Honestly, I don't even want to think about it any more. My brain can't handle this x)

[thin stratus]

#multiplayer message

[gloomy tiger]

Argh lol

[thin stratus]

I still need to figure out my main Character + other Character issue.
I don't want to.

Multiplayer is so not fun if you have a Designer that actually doesn't want to create standard UT.

[gloomy tiger]

I'm postponing a really annoying scenario as well, here at Slackers since AM.

[thin stratus]

Actually, now that I mention UT, how do they do the redeemer

BRB

[gloomy tiger]

Probably not as bleeding edge as yours but hey

Good luck

[twilit radish]

What's your scenario?

(If you can tell I guess)

[gloomy tiger]

Ah, I have a TSoftClassPtr<xxx> in a UDeveloperSettings

When I boot the editor, it does not work first time (null reference) - but if I just go to the actual Project Settings menu and re-select the class I selected before and play it again, it works

[twilit radish]

🤔

[thin stratus]

The thing you select

Is that in a different Module?

Cause I had that issue when I was referencing something from a different module, and the variable initialized before the module loaded so it couldn't find the asset

[gloomy tiger]

I mean, not really sure. It's just a class within my project.

I open my editor, this is how the settings look like. I click play. It doesn't work (nullptr)

[thin stratus]

For me it was a class coming from a plugin

[gloomy tiger]

If I just select None and put W_Cheats again, it works (not nullptr anymore)

[thin stratus]

But it loads with W_Cheats?

Or is it visibly none when starting the editor

[gloomy tiger]

Now that you asked, am really not sure

Oh, sorry yes

It loads with W_Cheats

[thin stratus]

Since it's Soft Class, are you loading it anywhere?

[gloomy tiger]

Now that you asked... probably not. Doh.

[thin stratus]

That would explain why it works after you actively select it

Which probably loads it

[gloomy tiger]

Is it safe to say that load on select happens syncrhonously?

I know I'm asking too much but just in case you know it from the top of your head...

[thin stratus]

I assume so

bool AUTRemoteRedeemer::DriverEnter(APawn* NewDriver)
{
    if (Role != ROLE_Authority)
    {
        return false;
    }
    if (Driver != nullptr)
    {
        DriverLeave(true);
    }

    if (NewDriver != nullptr)
    {
        CurrentFuelTime = MaxFuelTime;
        Driver = NewDriver;
        AController* C = NewDriver->Controller;
        if (C)
        {
            C->UnPossess();
            NewDriver->SetOwner(this);
            C->Possess(this);
            AUTCharacter *UTChar = Cast<AUTCharacter>(NewDriver);
            if (UTChar)
            {
                if (UTChar->GetVelocity().IsNearlyZero() && UTChar->UTCharacterMovement)
                {
                    UTChar->UTCharacterMovement->AddDampedImpulse(FVector(0.f, 0.f, 4000.f), false);
                }
                UTChar->StartDriving(this);
                UTChar->PlayerState = PlayerState;
            }
            DamageInstigator = C;
        }
    }

    return true;
}

Also, I'm disappointed

They do the same thing I do

But they don't have GAS back in UT times

sigh

Maybe I just have to check if the Character is possessed or not and based on that change the Prediction Enum on the GA

Or just have a Child for non-possessed Actors

AController* C = NewDriver->Controller;
if (C)

Also please don't do that

Freaking C

[gloomy tiger]

C lmao

[gloomy tiger]

neat

[thin stratus]

Ya well, guess 2 GAs it is

F*ck it

Back to building non-lego brick F1 car

[hushed heart]

Hello! Apologies for reposting, I have what's likely a bit of a scrubby question, but hopefully quite quick to answer. I know that OnRep functions will let clients know when one of my properties is replicated down to them. Is there way to get an OnRep for transform-related stuff? Like an OnRep for my clients when they receive a new actor location? Thank you!

[twilit radish]

Nevermind, that was totally not what it was supposed to be 😅

[crisp sable]

Let's say I have Player A running a listen server and Player B connected to the server

If player B triggers a level streaming volume, will Player A also load the streaming level that player B just triggered? Or do I need to add some extra code to tell the player A to load the level.

The reason I need player A to load the level is because he needs to have the collision information loaded for the streamed Level or else player B will fall through the world.

Is this all done automatically in ue4.27? Or do I have to add extra code to handle this?

[low helm]

I believe the intended framework would be for you to load all the levels on the server, probably at all times

Or maybe try to do it simultaneously

[crisp sable]

Ah I see..

[low helm]

But no I don't think any of that is done automatically for you

[crisp sable]

So have the listen server load all sublevels

And the client will just load the sublevels when he triggers them

[low helm]

Yeah if your server memory can handle it then do it that way

Also has rendering implications on the server

Which makes me wonder if you can load a level without making it visible, but the collision is still there

[crisp sable]

Yes the listen server would have to have a lot of memory or somehow I can figure out how to only load collision

[twilit radish]

To properly answer. There are several methods you can override within C++ from the actor:

/** ReplicatedMovement struct replication event */
UFUNCTION()
virtual void OnRep_ReplicatedMovement();
/** Update location and rotation from ReplicatedMovement. Not called for simulated physics! */
virtual void PostNetReceiveLocationAndRotation();
/** Update velocity - typically from ReplicatedMovement, not called for simulated physics! */
virtual void PostNetReceiveVelocity(const FVector& NewVelocity);
/** Update and smooth simulated physic state, replaces PostNetReceiveLocation() and PostNetReceiveVelocity() */
virtual void PostNetReceivePhysicState();
```Note that if you use the OnRep you need to check if it's actually replicating movement as apparently there's something whacky about that according to some comments inside of it.

[low helm]

I tend to just turn on client authoritative movement, so I can just do whatever I want on the client and the server just trusts, nobody has bothered to hack my games yet

But that's partially because I never released them

[hushed heart]

Ah that's great, precisely what I was looking for, thank you! I'm basically hoping to use this to have the client lerp to the new position to help reduce jittering. Hopefully that's a sensible way of doing it! Hopefully. Either wya, that's really ujseful to know, thank you!

And hah, that was to be my last resort, just trying to build in some good habits

[low helm]

You're making your own movement system

[twilit radish]

Tbh the default actor position replication system is not great. So no, not really.

If we're talking characters then yes, you're reinventing the wheel.

[hushed heart]

I am not, really, that's a project for the future for sure. Gosh I sure would love to just use the Character Movement Component but it's not suitable so I'm doing some terrible terrible things to navigate around it. It's just for a small project so it's not a big deal

Since my pawn is wider and broader than it is tall, the blasted capsule restriction is the only thing stopping me from using the CMC, alas

If there's a way around that with the CMC I would super love to know! But I think there isn't, unfortunately! If I could just use a fat capsule, that'd be great, ahaha.

[twilit radish]

Without modifying the engine source code no.

It's definitely annoying that it doesn't easily allow this though.

[hushed heart]

It's super annoying! I wonder if it would break if I went into whatever source code prevented the capsule's half-height form being smaller than the radius.

Something to try later perhaps, I don't need it to be super amazing quality right now. I find it super weird that, out of the box, there's no convenient way of having clean networked movement if you don't want a standard capsule collider.

Thanks for the help, though! Much appreciated.

[vagrant grail]

What's the difference between using a "has authority" node and putting your code on server side with a custom event server sided ?

[latent heart]

HasAuthority will only run if you're already on the server.

A server side event will only be triggered from the server or be sent to the server if run on a client-owned actor.

[serene furnace]

Hello I have a question about a weird issue that I have,

I'm running some testing into a Listen client server that is running 2 clients and the server.

The issue I have is that some clients dont even spawn sometimes, they stay "stuck" and dont possess / spawn a pawn, my code has been working since beggining of my project and never got changed

[vagrant grail]

then I don't see what it's purpose as if you're already on the server you don't need a node to tell you that you're on the server again 🤔

[serene furnace]

moving the spawn looks to be making it a bit better, but verry not a real a solution

[torpid girder]

LogNet: Error: ReceivedRPC: ReceivePropertiesForRPC - Mismatch read. Function: ChooseCharacter_Server 

could this mean the client code and the server code are out of sync?

[thick jungle]

question time... my player's characters DO replicate their rotation, but not their position. For example, if I execute the Jump command server-sided, neither client sees it happen.. I'm guessing I'm missing a setting somewhere?

[latent heart]

The point is you might not know you're already on the server.

That's why you have to ask.

Obviously if it's run on a server-only object, like game mode, it will always be true, but there are many, many circumstances where you have to check.

[vagrant grail]

So for instance, does this code need to be on the server ?

[latent heart]

I don't know. Maybe? Depends on your game.

[surreal niche]

Hello people

[vagrant grail]

I have a zone where the player needs to overlap it between 2 hours and if it's the case validate his task (boolean set to true)

[latent heart]

I will tell you, that code will run on the server and every client. It will be executed locally on all of them.

Just do it on the client as well. You can always validate if you're in the right zone when you tell the server you're doing things.

[vagrant grail]

so I leave my code like it is ? 🤔

[thick jungle]

if you wanna be save and understand what's going on, I'd suggest server-side that bit of code

that way all related code will only be done server-sided and therefore at least always be identical for everyone

[vagrant grail]

Like so ?

[latent heart]

Yeah, just make sure when you do whatevre you need to do, you check it on the server too.

[thick jungle]

if your server has authority over this object? yeah

[vagrant grail]

If someone joins mid game will he receive the right state of the "IsEnabled" boolean ? Or should that boolean be a repnotify ?

[fossil spoke]

All replicated variables have their current state as seen by the Server passed down to connecting Clients.

RepNotify is just a function that triggers when the value of that variable changes via replication.

[latent heart]

"All"

Those that are chosen to be passed down.

[serene furnace]

Any ideas for my issues ? 🤔

[thick jungle]

variables shoud always be replicated from server-side to clients by enabling the variable's replication (as well as the actor's replication boolean). Ah, DevilsD was faster ^^

[twilit radish]

@serene furnace I would recommend you check the logs, perhaps something in the map moved and blocks a spawn. Usually the engine will notify you of why a pawn can't spawn or similarly will tell you if something is wrong 🙂

[torpid girder]

novice question, when your dedicated server creates a session and you give it a name, should it be unique?

the examples are hardcoded text

[serene furnace]

Well I could not reproduce the bug with logs unabled x)
I will check that out and post again if it happens again ^^

[fickle igloo]

Heyo, is there any resource/guide/best practice for non-exploitable, client-predictable, RNG in multiplayer? Something like how auto-attack crits might be dealt with in a MOBA (all clients can predict the crit happening, but still server authoritative).

[noble sentinel]

Im using this for multiplayer connections but it isnt working, Im using spacewar appid with developer build, not shipping

What can be the problem?

[hushed heart]

Hello! Sorry to pop up here again, weird question just in case anyone might have experienced this before. I have replicated movement working fine hip hip hurray, for now it's on a Listen-Server. The only issue is that, for some reason, the listen-server client's pawn moves incredibly slowly. i'm setting it using AddMovementInput in server-only RPC, and noticing tht it considers its velocity to always be zero, so something is causing it to reset back to zero again. Using 2 clients, the other one works absolutely fine. It also works fine if I switch to a dedicated server, which I may just end up doing.

Don't worry, this code doesn't have to be super pro and shippable, it's just my own messing around, but I'd love to know what's going on as I seem to have exhausted my leads. Any help would be great, thank you!

[ocean dust]

Hello, all. How would I uniquely identify a newly-connected PlayerController? I want to spawn in my players when they connect, but only onto PlayerStarts that have not already been assigned to other players. However, there doesn't seem to be a way to assign PlayerStarts without custom code and no way to identify PlayerControllers relative to the others in the server (such as "this is Player1 (who is also hosting), and this is Player2 (a remote client), and so on") such that I can easily spawn them where the they need to be when the game starts. Is there some functionality I am missing or is there a canonical way to do this?

[river hazel]

There is a function that is responsible for choosing a playerstart..i think on gamemode? I think you would have to track which have been used with by holding onto an array of the used ones or something...but it's a pretty common thing, you might spawn a team near each other or have different sets of player starts for different modes.

You should be able to use hasauthority to tell the difference between the listen server and remote clients.

[ocean dust]

GameMode::ChoosePlayerStart is the method responsible, but it has no simple way of looking at the incoming PlayerController and relating "this is the 2nd player, they should be spawned at the PlayerStart with the tag P2".

Seems like the answer is "custom code and lots of loops"

[sinful tree]

You would assign the incoming player controller the identifier that you wish during OnPostLogin. You'd then override ChoosePlayerStart and read your custom player controller and read the identifier you've assigned.

[twin juniper]

It can be pretty easily done from the HandleNewStartingPlayer event in your game mode. From there you would have a variable called PlayerCount or something similar. Check if the player count is even, then assign it the appropriate spawn location.

Oh and then obviously increment the player count variable

[grand kestrel]

I have some glaring issues; this is PIE as a client without any artificial latency and have 100ms ping, and then the concerning ActorChan_FindOrCreateRep count. I could use some advice on where to start with debugging this to find the culprit(s)

[ocean dust]

Ok, thanks this is what I am building towards, just wanted to make sure I wasn't missing any obvious mechanisms (has happened A LOT)

[twin juniper]

Yeah definitely. What I said about checking if the count was even is only really applicable for a team game. If you wanted to have all the players spawn at different locations you could in your game mode construction script get all actors of class for your player spawn, then tell each new player to spawn at the player spawn index that is equal to the player count.

[deep shore]

are you using a character movement component? if that’s the case, you don’t need to set up server events at all - if you replicate movement all of this is already programmed into the component.

[south crest]

why if i turn on simulate physics for the character mesh (replicated component), it collapses like a ragdoll on the server how i want, but on the clients the character collapses like a stiff wooden plank? i dont need to sync the physics but just make the ragdoll happen on all clients...

[thin stratus]

You should have some sort of RepNotify Variable that toggles this

Replicating the Component doesn't mean the Physics Boolean automatically replicates

[hollow swallow]

Would anyone have a chance to help me resolve an issue. When i start a game, the clients can move / look around, but the host cant. He can still see the other players moving around but its as if he has no input at all

That is on the player controller

and that is on the game mode

[thin stratus]

Why the RPC though

Wouldn't it make more sense to just limit BeginPlay to Authority and then directly talking to the GameMode?

Also the GameMode already has a lot of good overridable functions to handle customizing the spawning of characters. If all you want is automatically spawn a character at a location for a player then there is no need to do it manually

For the "no input" part. Are you setting InputMode anywhere?

Are you sure your Server properly set Game only input mode?

@hollow swallow

[hollow swallow]

Hey mate, i am really new to unreal, this is my first project. I have done it this way from a video tutorial series i am following. I have checked all the blueprints and they all seem to match up. How can i check that the server is set to game only input mode?

just using the listen server in the project at the moment

i tried adding set input mode game only after the possess. still no difference

[thin stratus]

Always annoying when video tutorials teach random stuff like that

Your server gets a character though, right?

Are any of the inputs for the server character triggering?

You could try disabling your spawn code and just setting your character as default pawn in your gamemode defaults

To check if it's your spawn code or not

@hollow swallow

[hollow swallow]

Yeah the character is spawning in. No input seems to be triggering for him though. ill try that now

Yep that works fine

and im 99% sure my code is identical to the tutorial (which is only 5 months old if that matters?) and it works fine on his

thats a screenshot from the video of his one

[thin stratus]

Man this is such a redundant thing to set up

GameMode has override functions for retuning a spawn point for the default pawn to spawn at

The transform returning node there is not really needed here.

But anyway, let's have a look at the code

What about the Default pawn you set in the Gamemode, was that empty before? Is it empty in the tutorial?

Is there any character in the scene already before pressing play?

Can you also try to change your PlayerController code to use

BeginPlay -> SwitchHasAuthority -(Authority)> GetGameMode -> Cast -> SpawnPlayer

?

So basically cutting out the rpc

@hollow swallow

[hollow swallow]

yeah im not sure, as i said this is my first unreal project so still pretty noob xD default pawn class is set to none in the game mode and in world settings, same as the video. There is no character in the scene only the player start locations. i will try changing the player controller now, 2 secs

That also doesnt work, same issue

[vagrant grail]

Does anyone know why my timer doesn't the clients but works for the server even if the timer is a component inside my Game State and started by the GameMode

[deep shore]

I’m trying to wrap my head around network optimization. I’m a bit confused about the relationship between network performance and CPU performance. Suppose an actor has a net update frequency of 100, when 10 would be enough. This is putting unnecessary stress on the network, but is it also having a negative impact on the CPU?

[prisma snow]

CPU has to serialize/deserialize messages etc. Also, for example if an actor enters relevancy range, it has to be created for that client, which also has a CPU cost

[twilit radish]

It’s not necessarily bad for the network to have a high update frequency (but definitely could be), Unreal will simply prioritize that actor more and may thus check more often if anything like the replicated variables changed. It does not send out random network data if it doesn’t have to. But why this becomes a CPU waste is because you’re now constantly checking that actor while if it as an example only has a few variables that don’t change often it’s unlikely to send any data over the network. Hence why you need to consider what priority you want actors to have.

[grand kestrel]

Bumping I s'pose. Anyone have an answer to this? Something messed up with my netcode making it inflate latency even in PIE

[upbeat basin]

I guess you already explained the reason yourself. I'm assuming you're calling the StartTime event, which is not an RPC so will only work where the event is called, from the GameMode, which only exists on the server. So you're just calling a function on a server, which is setting a timer on the server. Making the StartTimer multicast might be what you're trying/wanting to do

[peak sentinel]

Today I was ranting because we are not able to have custom net update frequency for subobjects

[twilit radish]

Did you make sure the emulation settings are not accidentally turned on in the editor? Also are you sure it’s constantly the case and not just a lag spike where it went to 100ms for a bit and then down again as it shows as “max”?

[peak sentinel]

I got angry so much that I wanted to modify the engine for that

[grand kestrel]

Haha yeah I did BP, project, and C++ wide searches for 'pkt' just to be safe, but I haven't used those for many years, I use clumsy for latency simulation

Its constantly the case

And its this one specific project, I tested others moments apart

Also it's a localhost connection ^^ there wont be spikes unless like you say, emulation settings are used; other projects are fine

[buoyant kelp]

I called a multicast function and just server executed it, as well as that when Client 1 picked up the weapon, Client 2 couldn't display the snap as Server. Why? How to solve? Help, plz... I spent all one day..

I called a multicast function and just server executed it, as well as that when Client 1 picked up the weapon, Client 2 couldn't display the snap as Server. Why? How to solve? Help, plz... I spent all one day..

[grand kestrel]

The FindOrCreateRep is a hint but I don't know how to interpret that at all, I'd rather just know how to actually track it down instead of having to throw stuff at a wall and see what sticks

[vagrant grail]

This doesn't work 🤔

[upbeat basin]

GameServer doesn't replicate to clients. So RPC's and replicated variables are useless on GameMode I believe

[vagrant grail]

So how / where to do the multicast ?

[upbeat basin]

Inside your component, just make the SetupTimer event multicast, for your case

[vagrant grail]

still doesn't work 🤔

[grave lynx]

Hello, inside a actor, I'm trying to enable inputs. The server can press the key but the client can't. even with a box, casting to the character and getting the player controller from it. I have 'No owning connection for actor' error

EDIT: I think I have to call afunction from the PC with a ref to this actor

[upbeat basin]

I wonder if the client is missing the RPC due to later connection

[vagrant grail]

This prints only on the server

[vagrant grail]

I think so

[upbeat basin]

Well you probably either need to setup the timer for the clients upon connection (PostLogin in GameMode can help) by sending them the current int Timer variable so they can continue from where the server left, or for me the simpler way is making the int Timer variable replicated and setting the the timer event only on the server

[vagrant grail]

The Timer variable is already replicated in the GameState > Timer Component

[surreal niche]

I zoned out and forgot to ask my question...

I wanted to ask, is there a good reason to have your gameplay tick in the server and client locked to a particular time, say 16ms or 7ms?

[upbeat basin]

It doesn't look like replicated from the first picture you sent, did you change it?

[vagrant grail]

I realised I had 2 timer variables, 1 in the game state and 1 in the timer component, now I'm using the game state one all the time let me show you

[upbeat basin]

This one should now sync the Timer value to all clients whenever they do connect as well as whenever it's changed

If you want broadcast hourly event then you can create OnRep function to check if modulo equals to 0 there

[vagrant grail]

Works perfectly now, thank you so much 🙂

[oak oracle]

hey devs , where i can save my data between maps ? So i got GM where players earns points , and after game ends it should send all players to the Main Menu where thay can see all earned points , where i can save it ?and what class or data i can use to identify user ? tried with GameInstance but didn;t worked

[upbeat basin]

Why did GameInstance not worked? Are you sure you're setting the stats on the client's GameInstance and not to the server's?

[oak oracle]

yes you absolutely right , i have checked and the function which handles it only got called from server , Thanks !

[atomic nest]

Hello everyone!
I would like to ask a question about UserWidget and RPC (I am making an online game):
I made a PickUp ball, when I touch it, a button will be generated, and when the button is pressed, an event will be executed. However, for the client, this operation must use UFUNCTION (Client, Reliable). At this time, my client player can activate this button through the ball, but the event executed by my OnClicked cannot be informed by RPC to other players ( It's like I'm entertaining myself).I later added the UFUNCTION for Server and NetMulticast, but it didn't work.
I feel like the problem is related to the UserWidget, since I know the Actor has the bReplicates boolean, but the network replication of the UserWidget and the events its buttons control is getting me stuck.
Can someone help me? Thank you so much!🫡

[twilit radish]

Hey, widgets are unable to do any networking calls them selves. They are client side only. The usual way to do things like this is to have for example a function in your player controller to do the networking.

🙂

[atomic nest]

Thank you for your answer, it seems that I have to find another way out, otherwise I will get deeper and deeper.🫡

[hollow swallow]

How can i rename a session?

or define one before its created

[twilit radish]

For C++ this should be it:
https://docs.unrealengine.com/4.26/en-US/API/Plugins/OnlineSubsystem/Interfaces/IOnlineSession/UpdateSession/
Cedric also has a great article on it:
https://cedric-neukirchen.net/2021/06/27/ue4-multiplayer-sessions-in-c/

For blueprints I'm not quite sure.

[hollow swallow]

can it be done through blueprints?

[twilit radish]

I don't see a blueprint node for it anywhere. There are for create, delete etc. but I don't see the same for update.

This is what seems to be the list: https://docs.unrealengine.com/4.27/en-US/BlueprintAPI/Online/Session/

[hollow swallow]

Cheers, ive started digging into advanced sessions now

[hushed heart]

Apologies, I was alseep when you replied! I'm not, I'm kind of doing something very cheeky and terrible using a floating pawn movement component.

But! Don't worry actually, I was running into enough new discrepancies on the listen server client that I decided to switch to a dedicated server model, as everything just works more consistently that way. Thank you though!

[solar stirrup]

Hey hey, quick question, wasn't there some new features in 5.0/5.1 or planned features that allow conditional component replication?

i.e. only replicate a component to X player

I feel like i heard something about it recently but I don't remember

https://forums.unrealengine.com/docs?topic=727659

Found it nevermind ^^

[dusky yoke]

Hey guys, when moving to a new level my different player classes are set to the server's player class. I set the class in the main menu, set it in the gameinstance, and then I call the gameinstance in the player controller when spawning in:
Is there anything else I need to do in order for the clients to get the correct class when joining a session?

[surreal niche]

Bumping my question here, if anyone can take a stab at it

[twilit radish]

In general the server spawns the pawns / characters players posses. So I'm not quite sure why the clients would need access to that specific class? Normally the flow for spawning a player selected class looks something like:

• Player joins the server.
• Sends over what class they selected to the server.
• The server validates any necessary stuff and spawns in the player pawn and grabs the controller to posses the just spawned pawn.

From there on the pawn should replicate towards the client at some point and that should be it 🙂

[twilit radish]

Setting the tick to a specific value is an optimization you can do to just have that actor/component tick less which in the end can save CPU time. Sometimes it makes sense to do that and other times it doesn't, you for example don't always need a perfect frame timing for something to happen.

[surreal niche]

I don't really mean in the sense of optimization though, I'm talking more about how they do it for the overwatch networking

I'm referencing a youtube video here https://www.youtube.com/watch?v=W3aieHjyNvw

It could be that I just misinterpreted it

[twilit radish]

In what part of the video is this being discussed?

[surreal niche]

t=1479

24:39

Diagram at 25:30

[twilit radish]

I'm not quite sure what they are referring to honestly.

Seems to be somewhat related to their player movement code? But not sure 😅

[surreal niche]

It seems to me that they are simulating at a fixed rate

And interpolating between those simulation frames

[green fjord]

guys what happen if i call rpc (run on server) unreliable on Event Tick if client has 120hz tick speed and server only has 60hz

[twin juniper]

Hi, this may sound silly - I'm new here. But is it possible to have a single server world in UE that can handle more than a thousand players? Without splitting into clusters? Of course if we have an extremely expensive and powerful server. How is it possible that WoW can handle 3000+ players, but I haven't seen it in UE yet?

[latent heart]

Probably not.

The client won't own the actor.

[frank birch]

Can I change UGameMapsSettings::TransitionMap during runtime? 🤔
should I? 🤔 🤔 🤔

[solar stirrup]

Yes, GetMutableDefault<UGameMapsSettings>()->TransitionMap = ...

Don't see any reason you couldn't

[radiant jolt]

If I wanted a dedicated server to quit after all players have left, where would I put this logic?

[solar stirrup]

Gamemode's logout function

[rich locust]

So I have an actor that needs spawning, and I have spawned it on Serverside, and this actor also is set to replicate. However it does not appear on the client side. Am I doing something wrong ?

[clever hound]

UFUNCTION(Server, Reliable, WithValidation)
        void Server_MoveForward(float AxisValue);```
```cpp
bool APlayerPawn::Server_MoveForward_Validate(float AxisValue)
{
    return true;
}


//Movement 
void APlayerPawn::Server_MoveForward_Implementation(float AxisValue)
{
    //MovementDirection.X = FMath::Clamp(AxisValue, -1.0f, 1.0f);

    if (Controller != nullptr && AxisValue != 0.f)
    {
        const FRotator Rotation(0.f, HeadCamera->GetComponentRotation().Yaw, 0.f);

        const FVector NewLocation = GetActorLocation() + FRotationMatrix(Rotation).GetUnitAxis(EAxis::X) * AxisValue * MovementSpeed;
        SetActorLocation(NewLocation);

        UE_LOG(LogTemp, Warning, TEXT("%f"), AxisValue);
    }
}```
All I did was this and it replicates the PlayerPawn movement to the server and the other clients. Why???? I thought I would have to check the location in GameStateBase class and send that to the clients or smth but do I not have to do it now or what? The client who is moving cant see itself moving tho so that is a problem

[clever hound]

Do I update the clients locations from GameState to all of the clients? How do I do that I can't come up with anything to write into the Tick() of the GameState? Or do I make it in the gamastate at all

[verbal tendon]

More coherent sentences recommend I would.

[clever hound]

Umm... what do you mean?

[verbal tendon]

I glanced over your paragraph twice, and can't quite figure out your situation. Less frantic typing a little more explanation on each point of your situation

[frank birch]

look at this bp of a Player State
so, Increase Counter is just a variable++;, nothing to worry about.
The idea is that the user calls the RPC, that increases the variable locally (predicted kinda thingy) and then calls the SERVER procedure that actually increases the variable. When the server ticks and updates, we had the already increased value and we are happy...
HOWEVER, this would increase twice the value on Standalone and on Listen-Servers. Any tricks here? 🤔

[clever hound]

Ok so...
I am trying to get all the clients to see each others movements.
Clients = Pawn classes
With only updating the movements from 1 client to the server (code above) it replicates it also to the other clients which is strange and I dont know why it even works when I thought I would have to update the player locations from server to the other clients separately.
Current problem is that the player who is moving can't see its own movement or any location change. So do I still want to update the location from server to all of the clients in GameState? Or what do I use?

[verbal tendon]

How can the client not see his own movement, are you not using a standard possessed pawn using a controller?

And yes that was already a lot clearer and allows other to assist you. Thank you.

[rose torrent]

is it efficient to replicate TArrays?

[radiant jolt]

What exactly should be included in a dedicated server build? For example it doesn't make sense to me that it should have login functions, widgets, etc

[clever hound]

Client1 can only see Client2 moving and client2 can see client1. In the middle of the video there is the server. But in both of the clients screens they are standing still even when im controlling them

They are pawns who have been posessed normally

bReplicates = true;
bAlwaysRelevant = true;
AutoPossessPlayer = EAutoReceiveInput::Player0;

[frank birch]

does this make sense?
Only call Increase Counter as a homebrew wacky prediction if I am not authority... right? 😰
I want to prevent ListenServers and Standalones from Increase Counter twice 😬

[edgy patio]

I may be wrong about that, but I believe the server will have a CallStack and then execute the RPCs in order.
So supposing there's no data loss and no lag at all. In you example case, each Server Tick it would execute 2 RPCs received from the client.

[winged badger]

You are sending too many RPCs, no advrrse effects except for extra cost

[winged badger]

Server RPC called from listen server is just a normal function

[frank birch]

RPC is not ran on server, SERVER is
The idea is to have some sort of prediction. So RPC increases locally (in good faith) and then calls SERVER who will correct you because it has the authority anyway

[latent heart]

Server is an RPC

[frank birch]

if I call only the SERVER function, I wouldn't see the value increase until after the network roundtrip

[latent heart]

Your logic is wrong, though

[frank birch]

please help me 😰

[latent heart]

If you already have authority, you don't need to run a server rpc. You're already on the srever.

Server doesn't mean "this runs on only on the server" it means "Send this function over the network to the server and run it there" (or run it locally if you're already on the server)

[frank birch]

so far I follow.
Now, my logic is:

• machine wants to increase a value

If a computer is not the authority (remote): Increase locally and call the server to please increase it also.

If a computer is the authority (either I am the server or this is standalone), use the function to increase in server since I am server anyway

[latent heart]

I would not do that.

I would do this:
I want to change thing:

• Am I the server? ** Change thing
• Am I remote? Ask server to change thing. Server validates that it's an acceptable change. Server changes thing (see **). Value is replicated back to the client (this is a setting on your variable, not a thing that you "do")

[frank birch]

I understand, but on the Am I remote? path, I press a button and I have to wait for the roundtrip for the light to turn on (or whatever)
This isn't a delicated/cheat prone function, so I am safe to assume the user will be able to perform the change and I want to do it immediately

[latent heart]

That is where client prediction comes in.

What you can do is assume that the server will say "yes, that's fine" and just change the variable.

But if the server doesn't change the variable for some reason, it has to tell the client that the change was unsuccessful. And the client still can't do anything with that change that the server may also have to rollback and fix.

Unless it's something very simple like turn a light on or off.

What you could do is make the light play a flickering animation until the server confirms it. That would work seamlessly.

The better and safer you try to make the user experience, the more complicated the code becomes.

[winged badger]

Problem with your prediction method

Client predictively changes value and sends a server rpc

[gray holly]

hey, umm

[winged badger]

Server does its thing and says no

[gray holly]

is there SUPPOSED to be desync happening in the default thirdperson multiplayer game?

[winged badger]

As nothing changed on server, it wont correct client

Client now locked in invslid state

[latent heart]

That's why you send the rpc back saying it was unsuccessful and the c linet changes it back.

It's not perfect. But it never can be.

[winged badger]

If you search desync in here

[frank birch]

ohhh, I thought that the server would overwrite the replicated variable on next replication tick thingy 🤔

[winged badger]

Youll find people use it for literally hundreds of things

[clear island]

depends what you mean with desync, if you pushed that blue cube and its in a different location in server vs client, that's normal since its simulating physics

[latent heart]

Variables aren't replicated if they don't change.

If the client changes them, the srever won't correct it until it sends new values.

[winged badger]

Your question is equivalent to "hey guys how can i fix a bug?"

[gray holly]

ya that's exactly what I mean

[clear island]

yea thats normal

physics cant be replicated

[gray holly]

Is there a way I can mark physics to be rep

really?

[clear island]

yep

[gray holly]

wow.

[winged badger]

And no

Physix is not deterministic

Same scenario, same machine, run it 20 times get 20 different results

[clear island]

I dont think theres any game engine out there with deterministic physics

so yea its pretty much expected

[latent heart]

People try to do it.

[clear island]

yea theres ways to fake it

[latent heart]

They just keep trying, bless their cotton socks.

[winged badger]

Some made it work, with 8 physics objects total and cystom physics engine

Rocket League

[clear island]

yea I saw their talk

[frank birch]

Ok, for what I need it now, (making UI change immediately and storing the value in the server) this is good enough 👍

[gray holly]

I mean dark and darker has synced ragdolling

[clear island]

many games have "synced" ragdolls

gta5 too

its not really 100% fully synced

[latent heart]

As long as your server never argues about the state of the light, it's fine, yeah.

[clear island]

but very close

such that it wont matter

[winged badger]

Its more of a ragdoll that stays in sync most of the time

[frank birch]

if it ever argues, I am going to implement the same as cpp does.
If you fail the validation you get a trip to kickedtown 🤷‍♀️

[clear island]

basically I think the idea is to simulate physics locally for a certain period, then at some point force a synced pose animation

the tricky part is knowing when to do it

but find the right time to force a synced animation pose + interping to location/rotation and that will be good enough

[gray holly]

It makes sense now that I think about it if what I have in my head is accurate, that unless you use lockstep synchronization (don't update anything until everyone has the data causing a delay on everyones machine before the gamestate changes) then an object with physics being interacted with locally is going to be out of sync and all things that physics object interacts with will be out of sync as well until at the very least the data is sent to re-sync them in which case it will look like a teleportation for any fast moving objects

is that correct?

so how exactly does rocket league do it? Because I have a lot of hours on that game and ocassionally it will do something called a "ghost hit"

where someone hits the ball and you see the ball start to change momentum and then suddenly correct itself and snap back to its previous location as though it wasn't touched

usually when this happens all or most players see the "ghost hit"

the more I think about it the more I think it could be made to be deterministic unless 2 players are interacting with an object at the same time

[twilit radish]

@gray holly Rocket League swapped out their physics engine with a fixed timestamp one that’s also deterministic. They basically predict whatever they can at that point as it will “just” work but still rollback positions if they get out of sync because of players bumping into each other as an example to keep authority.

There’s a cool GDC talk about it: https://youtu.be/ueEmiDM94IE?t=1413

[prisma snow]

This is probably one of the best and most difficult to develop networking models that I know

[honest rain]

Hello there !
I have an actor in my scene, with a custom event set to 'multicast' so it executes both on server and client, which runs fine.
When I take this actor and instead of having the parent class 'actor', I put it as 'Chunk', which is a c++ derivated from class actor.
But when changing this parent class, the multi cast event won't fire on the client, only on the server, does anybody have an idea why ?

this is my class declaration : class MULTIPLAYERSERVER_API AChunk : public AActor

and I do set the replication in the declaration : Mesh->SetIsReplicated(true);

the actor is visible both on server and client though

[real ridge]

it is better to use game mode and game state for mp than game mode base and game state base?

i just realized i have both base in my mp game

but its in c++

[honest rain]

I am not using the game mode at all to do this

[real ridge]

u dont have game mode in game? wtf 😄

[honest rain]

I mean I have a game mode, but not transiting through it to get my multicast going 😆

[verbal tendon]

How are you moving them?

[clever hound]

@verbal tendon only with this (reply)

[wheat niche]

Hey, i have a problem im trying to run a custom event from a client it tries to call SetMaterialServer it replicated (run server only) und and multicast if i press k on the server it works but for the client it wont do anythink can someone help me

[verbal tendon]

I see. Since you are using pawns, I would suggest using the appropriate moving component: PawnMovementComponent

I have no personal experience with that as I usually work with Characters for player controlled actors, but it should work

[prisma snow]

Replication design question: I'm brainstorming about how to replicate our units' combat for large unit counts. We do use GAS, but if we keep it will have to be modified so I'm trying to think a concept first:

Targeting will be server-only and replicated to clients. But once units are in range and start attacking, I am thinking several alternatives:

Attacks are very simple (shoot/wait until recharged, and repeat). So I could send an RPC each time an attack is launched, or maybe some boolean flag ("isInCombat") that serves as start/end point to the attack loop, which would be less bandwidth intensive, but harder to control in the future (for example, imagine that the unit activates a attack increase ability).

On the other hand, health is also calculated on the server and replicated to clients. I could add the new health together with the attack payload, but then I'd be RPCing state changes, where probably a replicated array serializer with health values would work best.

Another option would be to RPC the new health values, but only kill units after server sends a special death event.

Reducing bandwidth and CPU usage for replication is a concern given the scale of the game, all of the above would be sent in batches through RPCs or Array Serializers

[latent heart]

No. You need a real actor. You have a choice of 3. Player state, controller and pawn/character.

You don't need to do that at all.

...and so what if you do have 15 ufunctions?

That's still a small pawn.

I'm not seeing how that is relevant.

Not possible.

I have no idea why your AInfo actor isn't just a pawn.

[modest crater]

TIL if a client predicts an action an locally changes an OnRep value to the same as the servers then the OnRep wont run when its received loool

Spent like 2 hours wondering what I was doing wrong

[hidden lion]

rep notify always

[latent heart]

Well that's inconvenient.

[prisma snow]

lol

[abstract pike]

I'm deferred spawning an actor and it's being routed through replication graph but it's ActorLocation is (0, 0, 0) despite having a valid transform set on the deferred spawn call. Any idea how I can get it to have the actor location I set at that time or do I just have to resign myself to updating it afterwards?

[latent heart]

Are you calling finish spawn?

[abstract pike]

Yes but it hits RouteAddNetworkActorToNodes immediately from the deferredSpawn call far before the FinishSpawn

And unfortunately it seems to be before the actor has it's location actually set by the transform passed in

[latent heart]

It's weird that that happens without multithreading.

is it appearing on the client in the wrong position?

[abstract pike]

Well I have replication decided by location at the moment

And so all of them are failing the location check and not replicating at all

[latent heart]

Ah.

[abstract pike]

I just tried out updating the replication status afterwards and that seems to work sort of

[latent heart]

Well it's the root component, not the actor, which decides the actor's location. Maybe it's adding the actor before the root component is properly initialised?!

[abstract pike]

But I think I'm missing some of the functionality because it's not replicating on the initial spawn

[abstract pike]

yea could be

In which case I'm kinda screwed

[latent heart]

You could turn off replication until after it's finished spawned.

[abstract pike]

what do you mean by that?

[latent heart]

Honestly, I'm not sure if you can even toggle rep on and off for a whole actor.

An actor has a setting that sets whether it's replicated at all, right?

[abstract pike]

Oh

[latent heart]

Turn it on after you've finished setting up your actor.

[abstract pike]

It's overriden by rep graph somewhat

[latent heart]

Ah. Well that was a kind of wild stab in the dark anyway. 😦

[abstract pike]

I guess I could just assume they're all valid if they're at 0,0 and then update properly once I get the actual location..

😬

[latent heart]

You're gonna end up with a ton of actors spawning at 0,0,0 and snapping somewhere else 😛

[abstract pike]

Gross eh

What an annoying thing to discover..

[latent heart]

The other alternative is to somehow do it without deferred spawning.

Does regular spawning actually work?

With the locations

[abstract pike]

We have values we set during the deferred spawn we need replicated in the first spawn

But maybe I could try a broken spawn with regular spawn just to check that

[latent heart]

You could hack that the same way hte object initialiser does it 😄

[abstract pike]

Unfamiliar with that but doesn't sound ideal 😆

[latent heart]

Yeah.

You can statically reference the OI from a constructor without using the OI constructor. So it must statically store the currently being constructed object on a stack or some such.

[abstract pike]

oh gosh, might leave that as a last resort 😅

[latent heart]

Haha.

Yeah. static FMyDeferredSpawningData 😄

[abstract pike]

it does 😭

Must be something to do with the initialization that happens when actually running the construction scripts which doesn't happen till FinishSpawn otherwise

[latent heart]

Yeah.

There's an actor lifecycle graph thing that says that somewhere.

[abstract pike]

@latent heart I got it 😄

Turns out, to set the root component location in DeferredSpawn it needs to have a cpp root component

This particular actor was just set up in blueprint

By adding a USceneComponent in cpp as the RootComponent in the constructor it works with DeferredSpawn

😁

[latent heart]

Ah ha.

Bypassing the need for the BPCS!

[abstract pike]

I still have the issue that Multicasts called right after spawn don't replicate to the client like they used to before rep graph though ☹️

[latent heart]

What are you doing with your multicast?

You fake could it with PostNetInit

Or, rather, is PostNetInit be what you should be using? 🙂

[abstract pike]

I can honestly say I've never heard of that

The actor in this case is for an ability's effect which is multicasting to show VFX

I could probably just play the VFX based on begin play or something like that

It's just annoying to go and recode them all given it was working on the old replication reliably

[latent heart]

Is the entire point of the actor to show the vfx?

[abstract pike]

No it does the gameplay effects as well on the server

The multicast is just how it kicks off the visuals

[latent heart]

Well, even so. It sounds like you want a non replicated server actor and a multicast to your clients to spawn their own vfx 😛

[abstract pike]

Well yea, because the multicast would reliably work immediately after being spawned that ended up being how they all got made XD

[latent heart]

Compartmentalisation!

[abstract pike]

Well it's tidy having an object that represents the whole gameplay effect

It just... doesn't work trying to use it so quickly after spawning XD

[latent heart]

Maybe maybe.

[abstract pike]

Long term it will ofc be changed

It's more how to make things work again now without all the rework up front

Plus the wondering why the heck it was so reliable under the normal replication driver

[latent heart]

Because reasons ™️

Almost as good as raisins.

Anyway, it's 2am and I've started to ramble. Time to sleep. Night!

[abstract pike]

Thanks for your help!

Good night

[latent heart]

Np

[honest rain]

When you spawn actors using a multicast function, is it normal that the actor detected on the server and the client ( after a line trace for example ) has a different name ?

[deep coral]

is it possible to change the Game mode or Game State of a level when loading a level? (ie, I want to open this multiplayer level with Game mode as Team deathmatch GM, instead of deathmatch GM)?

[fossil spoke]

Usually you will create a sublevels that contain all the features of the same level except they change their GameModeOverride to a particular mode. Then instead of loading MyLevelBase you will load MyDeathMatchLevel that contains MyLevelBase inside it.

[misty stirrup]

if two servers are on the same level, is it possible to pass a player between the servers?

[fossil spoke]

What do you mean exactly?

You can tell that Player to join another Server, sure.

[misty stirrup]

like if the player was in a grey box map, there are two dedicated servers, and i called APlayerController::ClientTravel could I just send the player back and forth between servers?

same level, same actors in theory

[fossil spoke]

The levels and actors in a Server have no bearing on a Players ability to join that Server.

[misty stirrup]

yes but there is seamless and nonseamless travel

i want seamless and im confused on what can cause it to become unseamless

[fossil spoke]

Seamless Travel is a travel operation for Clients that are connected to a Server to a new map whilst remaining on that Server.

[misty stirrup]

ohh

[fossil spoke]

There is no Seamless Travel between Servers, that would be considered a Non-seamless Travel.

Also known as a Hard Travel

[misty stirrup]

just seems like it would be super useful lol

[fossil spoke]

Its just not how Unreal is architected out of the box.

[grand kestrel]

Did you guys notice that servers and clients don't have an accurate deltatime in CMC's PerformMovement() and therefore physics loops also? TickComponent works as expected, though