multiplayer

[vivid seal]

for example, my basic UseAbility() function in the child class (PlayerAbilityHandler) checks right off the bat if I am the server. If so, it just calls Super::UseAbility() and that's it, sending the result back to the owning client in an RPC. If not, I check for AutonomousProxy, and if that's true then I do all of the client prediction and end up sending a Server RPC to call UseAbility() on the server.

[covert garnet]

@vivid seal In GAS there is only one class(AbilitySystemComponent), client-predict call and server call are different functions

[winged badger]

@vivid seal compose

make 2 UObjects with those functions, and instantiate one depending on authority or not

[azure hollow]

of course dude! 😄 Would be too much otherwise I agree, so setting up dedicated servers seems to be the best choice?

[hybrid zodiac]

Hi all, I have a problem which is driving me crazy. In my game mode, the match state is somehow being set to InProgress without me calling SetMatchState and I cannot figure out which part of the code is calling it (I did a ctrl-shift-F and searched the entire project for instances of SetMatchState and there are none I don't know about)

I noticed in SetMatchState within AGameMode there is a log to LogGameMode every time it's changed, how do I view the output from LogGameMode?

[finite kettle]

Try put breakpoint in the SetMatchState method and check call stack, it works for me most of the time.

[hybrid zodiac]

@finite kettle Ah good shout, thanks, I'll remember that next time! I actually found the cause of the issue, which makes it all the more baffling that the problem only just popped up now, years after development started. It's in HandleNewPlayerStarting

Just had to override it to do nothing since I'm handling player joining logic

[finite kettle]

But to answer your question, AGameMode is starting game when one bot/player is logged in game by default. If you want to start later, you must set bDelayedStart to true

[hybrid zodiac]

@finite kettle Ah that might explain why the problem only just occurred now then, I might have removed the bDelayedStart flag by accident or on purpose without realising what it did

Thank you for the help 🙂

[pine bobcat]

Hey guys, I got a weird problem for my character movement in multiplayer.
Server looking at client character is having a smooth movement, while Client looking at server character moves with jitters (shown as the videos).
I put the AddMovementInput node in EventTick as the image shown. I had the character replicated and movement replicated.

Does anyone got an idea how to fix this?😫

[potent cradle]

Hmm, is it right that pressing F8 to detach from PC during PIE with 2 clients (play as client), would be the server view? Or am I mistaken and is it still client side? I saw some behaviour that led me to think this, but I might be totally off base.

(pawn seems to disappear totally for some fun reason 😄 )

[chrome yoke]

hi, so i wanted to implement multiplayer feature for my mobile game, i wanted to make it with unreal engine online subsystem itself but i dont have much multiplayer knowledge so i wanted it to be like someone hosts the match and the client dont have to put the ip but like he clicks on join and then he automatically joins a randomly hosted match so is this possible and how without a dedicated server or any other solution? please help

[worn lodge]

@winged badger Thank you for the answer, I had seen a few post on Answerhub mentioning that OnPostLogin was safe for that logic, but I see the intended way is as your stating. I will be looking into this today and hit you up with results. Thanks a lot.

[candid escarp]

Hello people! Does someone know how to correctly interpolate positions for clients via blueprints? I am doing the stuff in the picture for clients and it seems to work, but I am too much of a noob to know and it may get imprecise later. Thank you!

[bitter stirrup]

Hey, I'm currently working on a 1v1 online game using listen-server architecture that will be released on steam (therefore, using Online subsystem steam).
I was wondering if there is a way for me to have a queue-like matchmaking system ?
I know how to create a session, find other players sessions, display them and join one of them but i would like something easier to use as a player. Just click on a search button and wait.
I could just look for sessions and if nothing is found after a few seconds make the player create his own but that seems a little simplistic.
Is there a function that i missed that would help me achieve that ? Or is it not possible to do it cleanly using a listen-server ?
Thanks in advance !

[winged badger]

@candid escarp that will choke your network for no benefit

you just need to replicate a single Vector in this case, DesiredLocation

and you let the client interpolate it itself on Tick

[candid escarp]

ah okay that means the tick thingy should be executed on the client only?

[winged badger]

if everyone has an Actor on same location

and that Actor is travelling with same speed to another location

everything is synced

server just shares the initial state

and each client does the same thing on TIck - interpolate to target

logic you used above wouldn't work for single player, btw

[candid escarp]

I want to make players see same ball positions

it's an online-only game so that's okay

[winged badger]

if you have a vector speed then FinalLocation += Speed * DeltaTime

there is no interpolation required in that scenario

[candid escarp]

oh okay

i will try that, does that mean, that I have to create a custom event that runs on clients only and is called by event tick?

[winged badger]

@bitter stirrup its pretty much if game not found, host a game scenario

[dark edge]

You could also have everyone host while searching, then quit hosting when they join a hosted game.

That way you don't have 10 people looking for a game with none of them hosting at that moment.

[candid escarp]

Is replicating the object itself enough or do I have to spawn another instance of the object on the client side?

I am not replicating movement btw.

[winged badger]

replicating the object will cause the client to spawn it

if its relevant

[bitter stirrup]

@winged badger So there's no way to handle it using steam to match 2 players and tell one of them to create the server ?

[winged badger]

without a custom server doing matchmaking, not sure there is

[finite kettle]

Hello!
I would like to ask a question about component replication. I need to have one persistent instance of component over multiple actor's respawns (destroy and spawn again).
Is it possible to detach component and attach it to the another instance of the actor? Would the net channels pair?

Thanks for any advice 🙂

[winged badger]

they would not

is that component in any way related to the player pawn?

[finite kettle]

It is AbilitySystemComponent

[winged badger]

it can probably sit on the PlayerState

not that familiar with GAS

[finite kettle]

Yea, but i need multiple ASC's

[bitter oriole]

@bitter stirrup Since it's 1v1, either player will need to host the game, so you can build your own matchmaking with average framerate for example as a parameter and have the highest performing player host once two players are matchmade together

[finite kettle]

Player has multiple pawns

[winged badger]

but you would just need to redirect the GetASC function

[finite kettle]

Is there any way how to pair them? Or it is a suicide mission?

[winged badger]

via playerstate, sure

copying a replicated component onto another actor... that won't work so well

its technically possible, but... yikes

[candid escarp]

That's a problem I wanted to take care of later, for now it requires one person hosting a game, which works fine

[finite kettle]

oh, I see 😄 So for me suicide.. Thank you! 🙂

[winged badger]

however many pawns you have

you still have the same PlayerState

and i have done a lot of stuff getting the engine to network the way its not meant to

i would not go down that particular rabbithole

[bitter stirrup]

@bitter oriole Yeah that's exactly what i want ! My problem is matching the players together. Currently my only way to do it is for a player to create a session and for the other one too look for it using find sessions but at that point one of them is already the server

[winged badger]

i am pretty sure the NetGUIDs will break

if you move it to another actor

which means you need to assign a new one.. .somehow

[dark edge]

Why not just, like, not destroy the actor

[winged badger]

which in turn means altering the engine

[dark edge]

Make being dead a state, not the destruction of the actor.

[winged badger]

i figured he already considered that before diving into crazy 😄

[dark edge]

I'm guessing this is something like an RTS with characters that can have persistent stat changes or upgrades to abilities?

[finite kettle]

I admit I didn't try to have more AbilitySystemComponents on single PlayerState instance, does it work?

[winged badger]

i am still very unsure why transfer the ASC if you have multiple ones

[finite kettle]

Something like that, it's MOBA. I can avoid destroying the actor, but it will bring a lot of work for the scripters.

So I promised them I will try to find another solution 😄

[winged badger]

then make a struct that your ASC can initialize from

and just copy that over

its like 1 struct and 2 functions at bare minimum

[dark edge]

Is this for like the main characters in the moba or subcharacters like summons or minions?

[finite kettle]

Main characters

[dark edge]

Destroying those seems icky but if you must do it, then you can figure out some way to save their stats etc to a struct and then reinitialize on creation

You are going to want that struck anyway for things like rejoining from disconnections or saving a game or whatever

[finite kettle]

Ye, thats what Zlo is saying, but I need to let ASC's logic continue (calculating GE's...).

😦

[dark edge]

Yeah, 100%, should not be destroying the characters. Being dead should be a tag

And resurrection/respawning can just be a gameplay effect then

And buffs can persist

[finite kettle]

Unfortunately this will probably be the best solution.

thank you very much for the advice @dark edge @winged badger

[candid escarp]

One last thing I wanted to ask: does all that mean, that I have to do all force and impulse calculations myself or can I still use Add Force etc.? I don't know how to get the velocity and rotation other than using get component velocity for the velocity and get world rotation for the rotation

[winged badger]

physics is not deterministic, so good luck keeping that in sync

[candid escarp]

As an example I would take a game like rocket league, the position and rotation of the ball for example. I don't know how much the network will get DDoSed if I update the positions for the clients at each tick

[dark edge]

Not at all.. that's like what, 8 bytes, 60 times a second? I'm sure your network can handle 3.8kbps per player.

[candid escarp]

Okay that sounds alright. Thanks to all, I am still learning about multiplayer syncing and this channel helps a lot

[winged badger]

problem is

you sending an update each tick

doesnt mean they will arrive each tick

or in order they are sent

[dark edge]

Yeah you need some way of smoothing the fire hose of data on the other end no matter what. Whatever you do, don't try to out engineer the built-in replication stuff unless you really know what you're doing.

[winged badger]

or that you have same tickrate

[candid escarp]

Okay I guess I have to read stuff about that, I haven't tried stuff like package losses etc.

If I do the same calculations on every clients side I should get the exact same results for each client right? But isn't there still a problem, if a client gets disconnected, the positions on the server and on that client would be different

[dense ocean]

Anybody know why my clients cannot see any other client or the server pawn's movement until about 10 seconds, at which point everyone snaps to their actual (server) location and from then on its good?

There's just about a 10 second period after each startup where the client can't see any replicated movement

[kindred widget]

Ignoring per second rates and whatnot for middle of gameplay. What kind of download size is generally acceptable for a decent game size as far as initial download when connecting to a server? All of the state variables and whatnot. Possibly considering something the size of ARK in scope, but with much lower player count per server. Are there any statistics on what kind of average connection a player might have for coop style games?

I'm mostly concerned with the ten minute load screen that games like that tend to have. I'm not close to that yet, but I really don't want to just deal with it when I get there, so I'm just looking for some general figure. More or less wondering if there is like a percentage of people who don't at least have like a 5megabit connection.

[potent cradle]

"I'm mostly concerned with the ten minute load screen"
To load what exactly? I'm not sure how that would be impacted by the connection speed. If there's a lot to load, that feels like loading from disk into memory, no? Something not really impacted by your connection speed.

EDIT: Missed your line about state variables. Strikes me as odd if that would really take up so much though 🤔

[mortal zealot]

Anyone got experience with Steam sessions? I am having a bit of a problem with getting a Steam dedicated server working. I can create a session and join via LAN across my network, but it doesn't work online. I don't have "Use LAN" checked. When I search for my online sessions in-game I find 3-4 sessions, none of which is my session (according to Steam ID). I can find my server in the Steam server browser in both "Internet" and "LAN" tab. Any ideas?

[clear sand]

Hey lads, back to dedicated server question. How do I prevent dedicated server from launching when I PIE as a client? I have it running standalone with specific map, so I don't need to run with PIE

[chrome bay]

play in standalone in editor, then open IP to the standalone instance you have running

Not certain you can join other standalone instances outside of the editor when using PIE though

[clear sand]

standalone does not provide info whether its server or not(its actually counts as server)

[chrome bay]

Not sure what you mean. Standalone instance needs to open a map with ?listen if it wants to act as a server

Standalone is it's own NetMode

To run PIE as a client, it needs a server to connect too

[clear sand]

Right, but macros like/#if WITH_SERVER_CODE always returns true on standalone

[chrome bay]

They will always return true anyway unless you do an actual Server build. They're eval'd at compile time not runtime

[clear sand]

Arent running UE from VS actually compiles code?

[chrome bay]

Sure, but WITH_SERVER_CODE is going to be true unless you did a Client build

Which you aren't doing if you're launching the editor

[clear sand]

Alright, but GetNetMode() should return correct values, right?

Ok, looks like its the way I needed. While its not connected to server - it stays as Authority, once I connected to remote dedicated server - all works as I expect

[grave notch]

Hi guys, is there any deep guides/tutorials about multiplayer in UE4? I need something advanced for lets say something like AAA quality project. How to properly build multiplayer architecture and make perfect synchronization between players (not FPS genre tho).

[limber gyro]

can some one give me a hand on how to craft a https request with unreal?

any one that has done that before?

[lost inlet]

use #if UE_SERVER for an actual dedicated server build

[kindred widget]

@grave notch Not really sure that a guide or tutorial like that really exists. If it does, someone should probably give it to quite a few AAA game companies. You don't usually get quality without a decent amount of iteration. You don't usually get experience without it either. It's worth noting that AAA doesn't necessarily mean quality either, just a bigger budget. On a side note, any guide promising perfect synchronization between all clients probably should be avoided. PTT means that something will be out of sync for someone or someone will see things before someone else, etc.

[grave notch]

Well by "perfect" i meant optimized realization. For lockstep and predictive types.

[primal peak]

Sooo I'm trying to use ClientTravel to join a server that I hosted on my local ipv4 address... But can't seem to and I get this error

void UOneGun_GameInstance::Host() {

    UEngine* Engine = GetEngine();

    if (!ensure(Engine != nullptr)) return;

    UWorld* World = GetWorld();

    if (!ensure(World != nullptr)) return;

    World->ServerTravel("/Game/CPP_BR/TestMap?listen");

    Engine->AddOnScreenDebugMessage(0, 5, FColor::Purple, "Hosted xD!!");
}
void UOneGun_GameInstance::Join(const FString& Address) {

    UEngine* Engine = GetEngine();
    if (!ensure(Engine != nullptr)) return;

    Engine->AddOnScreenDebugMessage(0, 2, FColor::Green, FString::Printf(TEXT("Joining!! %s"),*Address));

    APlayerController* PlayerController = GetFirstLocalPlayerController();
    if (!ensure(PlayerController != nullptr)) return;

    PlayerController->ClientTravel(Address, ETravelType::TRAVEL_Absolute);

}

These are Exec functions

I open these as standalone games using powershell btw

[tranquil yoke]

Is it possible to stream Level , when we join to server, I want to reduce my Level loading time to as minimum i can have, if possible seamless.

Right now it take 6 to 7 seconds.

On Android though.

[winged badger]

if you know what level are you loading into in advance

and you have an asset with weak pointers to the major assets in your levels

you can start preloading assets

before you call open level

we do that from our lobby, as soon as the map is selected, the game starts preloading the level's prefabs off thread

and it shaved a couple of seconds from PC loading times

[tranquil yoke]

you mean weak pointer to an Object and that Object will have all the Hard References to the Level Items.
and do AsyncLoad for that Object Class / or something.

Does soft Reference works the same , if i keep asycn Load that asset.

[meager spade]

SoftObjectPtrs

[twilit badger]

Hello, Im wondering if anyone can help me convert an actor so it replicated (Actor is a vehicle), I have the physics and i have it replicating but its laggy and does do what i want it to do. Please PM as i dont usually come here and i probably wont see it here

[pine bobcat]

anyone please 😭

[winged badger]

if your skeletal mesh component is set to replicate

turn it off

[pine bobcat]

No, the skeletal mesh is not set to replicate 😦

[drowsy arch]

any tutorials on making c++ 3rd person controllers

for multiplayer

[twin juniper]

GAS Shooter has first-person/3rd person switch, you can just disable the switch, and always keep in third person... It's not a tutorial per se, but it's primed and ready for multiplayer following Epic standards 🙂

[winged badger]

there is an extensive Deadalic blog about TPS camera though

interesting read

[drowsy arch]

can you link?

[granite badge]

@pine bobcat You could try changing the minimum frequency of updates on the actor

[steel fox]

IsLocallyControlled() returns always false in my pawn in BeginPlay() or PostInitializeComponents() after calling ServerRestartPlayer() from the pawn's controller, what do I have to do?

[chrome bay]

Both of those will be way too early

You can look at the possess functions, or the controllers 'SetPawn' function

[steel fox]

I suppose that GetWorldTimerManager().SetTimerForNextTick(...) requires tick to be enabled right?

With that function I got it working...

[chrome bay]

Doesn't need to have tick enabled, but in multiplayer that's asking for trouble still

no garauntee the possession will be received by the next tick

usually will in this case, but delays/timers to get around network issues is asking for hard-to-find bugs later

[pine kernel]

hello someone is good at making local multiplayer inputs ? im trying to make a fighting game where you can control second player with controller but when i open my level blueprint and create player node , the second character doesnt move when i use controller..

[twin sable]

how do you guys sync attack animations between the client and server? do you use a rpc and play a montage? or change a value to transition to a different state?

[winged badger]

RPC a montage here

or a state that starts a montage

depending on the use case really

[twin sable]

ok I'll try that. getting timing issues with players spamming attacks meaning the state is stuck on attack

and if I set the animation to loop it will start looping as its transitioning out which looks weird

I'll try playing montages instead

[winged badger]

you can arrange all the attacks in a montage sequence

then just change which sequence the montage is playing

and RPC that

less payload if you can make it work

1 byte is sufficient

[twin sable]

@winged badger do you know if theres a simple way to only play a section of a montage?

I've set the attacks with their own sections like this. but playing a montage and skipping to a section always plays the entire montage from that point

maybe I should just have separate montages for each attack

[hybrid zodiac]

Hi everyone, I have a challenge I can't quite figure the answer to. I have an admin panel that server admins can use to modify the map cycle for the server. The map cycle is held in in a TArray of a custom struct called FMapCycleEntry within the Game Instance, so I need to somehow send the map cycle to a client, but only if they open up the admin panel and want to look at the map cycle. I don't want to replicate it to everyone as it's quite a bit of information and likely a waste of bandwidth since only 1 or 2 players will have admin privileges

I thought about having a client function which passes in the TArray, like Client_SendMapCycleData_Implementation(TArray<FMapCycleEntry> MapCycle); but it doesn't like that

[winged badger]

@twin sable we have synced network clocks and all our networked montages come with a timestamp

so we adjust the start time or the play rate, depending

[hybrid zodiac]

@pine kernel Make sure the player controller owns the second character. You cannot execute server commands like movement input unless you own the character (you'll get a warning in the log saying something about "no owning connection for actor"

[steel fox]

Is there a good tutorial about HUD in multiplayer games? I'm getting crazy trying to add widgets to my HUD at Character spawn, I'm not even sure abouth what should I do, adding widgets from actors BeginPlay or PostInitializeComponents doesn't always work, so I'm assuming that I have to tick my HUD and get from my character if the HUD can display a certain widget or should Hide/change it with a different one, but I'm not sure, I'm getting very confused about them, any hint?

[bitter oriole]

Use the built-in HUD class

it will work exactly as needed in multiplayer

Add widgets in beginplay and you're done

[steel fox]

My issue is that trying to add specific widgets for each player from BeginPlay() is that IsLocallyControlled () doesn't always work as intended from there, so I can't know to who I'm exactly adding the widget, yeah by checking the role or HasAuthority I can know who is the server but nothing more

[bitter oriole]

Hud is client only.

[steel fox]

So trying to acess it in begin play will return nullptr for non owners? Ty a lot

[bitter oriole]

Beginplay will only fire on the owning client since it only exists there

[steel fox]

What about replicated actors? I Am having it fired both on server and clients, so am I doing something wrong?

[bitter oriole]

Hud class does not exist on sever

Are you sure you are using that class for BeginPlay

[steel fox]

Yeah, understood that and know I've done what I needed to

[steel fox]

If I spawn replicated actors in server RPCs and I put an AddOnScreenDebugMessage in BeginPlay() I get several prints on screen for each spawned one

This are spawned by GameMode

[bitter oriole]

Look

You asked about HUD widgets

You should be using the BeginPlay event of your HUD class - as in, inheriting AHUD in the engine

Spawn your widgets there and you're just done, no RPC or replication needed

I'm not sure what you're asking about replicated actors

[steel fox]

Maybe I got a bit confused by that, everything works fine and as I need now, I'm asking nothing about replicated actors, thank you a lot for your help

[bitter oriole]

Alright so

I'm getting crazy trying to add widgets to my HUD at Character spawn, I'm not even sure abouth what should I do

My answer is to use BeginPlay of your AHUD-derived HUD class

If you need character-specific widgets based on whether the character is there, you'll indeed need to tick and decide what to display

[peak notch]

how can i get the playernames from a session

is it possible?

after doing a Find Session

[chrome bay]

it's not no

You can only get the information that the session is "advertising" - which is usually as little as possible

[bitter oriole]

Though, you can get the player name from Steamworks based on the player ID in the session info, right ?

[chrome bay]

I think it depends on the OSS... I wonder if steam let's you retrieve all user id's for a given session id

[peak notch]

ok gotca

[peak notch]

it's android platform based

so basically googleplay will come in play

[bitter oriole]

Not familiar with that, but you can try looking into the OSS code

[peak notch]

Sorry but OSS?

Oh online subsystem

But how can one look at the google play subsystem code

[bitter oriole]

Not that, but the UE4 OSS implementation for Android, see if you can find stuff

Though I guess the first step is to check how you can get the information in the Android SDK

Second step would be to expose it in OSS

[peak notch]

Ok

Let's search ig

[upbeat basin]

Is it possible to replicate dynamic textures somehow? I'm trying to download avatar image of players to server and set a replicated Texture variable but although the server successfully downloads and sets the variable client value is always null

[bitter oriole]

You can definitely replicate textures but you'll need to handle it yourself

Compressing the raw pixels to PNG or JPG and replicating that in a custom NetSerialize method

[twin sable]

Thats smart, but I gotta run it client side asap for that crispy game feel 🙂

figuring out how to balance client side prediction and server authority is a bit difficult though

[peak sentinel]

Reading Tim Sweeney's UT2004 article about replication, are these values still usable in UE4 too?

[winged badger]

its out of date a little

when server picks actors to replicate, if will replicate them in order of net priority, it has nothing to do with bandwidth

actors that get skipped for replication panic, increasing their net priority over time

until they get replicated

[peak sentinel]

I see, thanks Zlo

[winged badger]

also its 3 for pawns/controllers, 1 for actors nowdays

[peak sentinel]

What do you use for Characters?

[winged badger]

tahts engine default

and character is a pawn

[jolly siren]

lol why are we replicating fish

[peak sentinel]

Right, okay, thanks 👌

[winged badger]

we left that on a default pretty much

but we incrased shot lived actors like grenades to 2,3 i think

@jolly siren to create the worlds first accurate network fish simulator?

[meager spade]

we are doing another network optimization pass soon 😄

[winged badger]

@upbeat basin if your network infrastructure allows for it, would be simpler to have a public server store and redistribute those

[clear sand]

hey lads, so I have dedicated server running standalone, however #if UE_SERVER returns false. What am I doing wrong?

I'm running it like Engine/Binaries/Win64/UE4Editor.exe MyProject.uproject ?GameMode -Port=myPort -server -log -nosteam

[winged badger]

running standalone from PIE?

because that checks if build target is server

[clear sand]

no, manually

[winged badger]

won't return true for editor binaries

[clear sand]

well I dont want to start it right with PIE client, because it automatically connects to server. I need to start it unconnected do some auth stuff and when it succeeded - connect to my dedicated server

[winged badger]

by the time you finish compiling

[clear sand]

I didnt find solution to skip initial connection to dedicated server

[winged badger]

the code was compiled... or not based on what that check returned at compile time

with editor binaries, it just won't work

it doesn't check that code at runtime

you can try, if you want a runtime check

if (GetWorld()->GetNetMode() != ENetMode::DedicatedServer)

(actors have GetNetMode of their own and don't need to call GetWorld)

[clear sand]

Hm, thats good idea, thx, I'll try

but is it better to replace it with #IF UE_SERVER when shipping game or I can keep this runtime check?

[winged badger]

whatever is inside #if UE_SERVER

won't even exist

if the build target is not server

code won't be compiled for the binaries, as if it was never there

[severe widget]

it's a great idea to keep as much stuff wrapped in #if UE_SERVER as possible

[harsh lintel]

are uobjects replicated by default or do I have to set a variable

[hot laurel]

https://jambax.co.uk/replicating-uobjects/

[limber gyro]

Does PlayerArray exist in the gameMode?

nvm that question was dumb

[young spoke]

So I have shooting in a montage
When the play click shoots it calls this multicast event so other clients can see the animation
In the timeline there is a trigger which calls an event called shoot
In the shoot event there is a hitscan function that draws a line trace
Works fine for the server

https://cdn.discordapp.com/attachments/714928089104122027/814262023381581834/unknown.png

But for a client 2 line traces are produced
But only 1 ammo is used

Any ideas why>?

[celest sleet]

I am trying to make a fireball explode upon impact replicate correctly. I have the server determine when the collision happens and its effects, but also sends to the clients where it exploded so they can spawn the visual effect in the correct location, to compensate for potential physics mismatch of the fireball projectile. according to my tests the code is being run on the client but there is no explosion. the visuals are working fine for the host player.

[cosmic trail]

@celest sleet show code on client, and how do you know it's getting hit? Sounds more like a visual spawn problem if you know the client code is actually hit, not so much a multiplayer problem

[wise zephyr]

guys i am using eos core is there a way to change the server name?

[winged badger]

@celest sleet you destroying that fireball actor in the same tick you MC the explosion maybe?

as the actor destroyed tends to beat the multicast then, and when MC lands, there is no longer an actor to execute the code

[wise zephyr]

is there a way to name the server with eos core in blueprints?

[winged badger]

if it works anything like other services

the session can hold data

and you can choose to interpret one of those data fields as a name when you display it

[wise zephyr]

nvm found it

[dark edge]

Don't destroy the fireball actor right away, just set it to some sort of state where it's not interactive and said it's lifetime

[celest sleet]

I found the problem, turns out the explosion size was not being replicated so it was exploding but with a size of zero.

[meager spade]

i handle my explosions in EndPlay of the projectile

it works well 😄

[odd sundial]

There is no FRotator equivalent to an FVector_NetQuantize is there?

[meager spade]

Rotator is just floats

so just quantize the parts, and convert back

[odd sundial]

Yeah I figured I'd attempt for the lazy-man route. I'll just do it that way.

[kindred widget]

@odd sundial It's worth noting that FRotators are compressed by default. At least I'm fairly sure you get the same thing in C++, can't see why it would be different. At least in blueprint, simply creating an FRotator property that is replicated and netprofiling it, shows it not sending a full 12 bytes. Which is consistent with the fact that it gets unwound and arrives on client with 0 to 360 rather than -180 to 180.

[odd sundial]

Thanks @kindred widget! Appreciate the really informative response.

That's awesome

[kindred widget]

Most rotators should only send with 4-6 bytes rather than 12. They all get compressed to shorts or bytes. I suppose they figured that 0.005 precision per angle was always more than enough for a simple direction.

[peak sentinel]

But Quats doesnt, right?

[upbeat basin]

I can already replicate textures that are present in my content. Is it because replicated thing is the path rather than the actual texture itself to reduce transferred bytes? So what you mean is that I need to replicate the data I receive from my downloaded image myself instead of trying to replicate it directly as a texture?

[winged badger]

if the texture is packaged, then you just need to replicate the asset pointer

nothing else

[upbeat basin]

Well not exactly but I guess we're doing something similar by storing player avatar URLs on our database (since there are players from multiple platforms that have different APIs for profile data). Currently it's the URL that is replicated and each player downloads every other ones images upon connecting the server. I wanted to download the image once on server to reduce our webservice usage and replicate the texture itself, so each image will be downloaded once on server (from our webservice) and will be distributed to the other players

It's dynamic textures that I download from web, so they're not packaged I suppose

[winged badger]

replicating URL and letting players download the texture from the webserver is way simpler then getting unreal to replicate the texture imported at runtime

add a sensible cap to the size of the texture they can upload, and it should all run smoothly

[upbeat basin]

I see, thanks for the headsup

[weary badge]

Can the GameMode in an online multiplayer call an event on PlayerControllers through an event dispatcher ?

[pallid mesa]

yes, sure take a look at Broadcast implementation https://docs.unrealengine.com/en-US/API/Runtime/Engine/GameFramework/AGameMode/Broadcast/index.html

[weary badge]

Thanks !

[grave notch]

How to handle ping if you want to make actions feels like it was done without ping? For example i click to move to specific position, i send that action to server with 50ms ping, and also i instantly start to do it locally (so you cant feel ping), so now server start to move me 50ms later and i have desync. I want server to understand that i had 50ms ping when i did that action so my position in server should be reached faster. Is it possible to do?

[chrome bay]

It's complicated

Character Movement has a whole prediction/reconcile system as part of it's movement

In a game where you are moving a character by clicking different position, you will likely just have to live with the latency

I presume you're moving it with AI, which means only the Server can really move it properly anyway

[grave notch]

Well actually its more simple, no pathfinding systems, just move to where mouse position was when you clicked (or holding, its probably harder that way). Actions come directly from player. Basically i want to move character forward by exactly player ping so it should be similar position on server and client (small difference in position can be handled automatically by character movement sync if i understand correctly). So main idea just to sync huge difference in position when you start moving. Not sure about what gonna happen if player starts to change moving very often.

[chrome bay]

Are you possessing the character?

If so, just use AddMovementInput to handle movement (client only) - and this will be handled automatically

[grave notch]

ye its your own character

[chrome bay]

Movement prediction is a lot more complicated than that

If you can leverage the existing system UE has, just try to use that

[grave notch]

you mean i need to move my character client only and server will do everything automatically?

[chrome bay]

If you move the character client-side only via the AddMovementInput functions, then yes it will be handled automatically

Assumes you have "possessed" the character pawn

And that will come with all the prediction logic the character already has

[thin stratus]

Terms and Conditions apply

[grave notch]

interesting, okay i will try

[rotund quarry]

Hey, so, I have an issue that Im unsure how to solve regarding movement jitter. While testing the game as standalone game with clients and server on same PC it all works fine, but when testing over Steam there is jitter most of the time, but not always. It all leads me to believe that its network's fault. Is there a way to see if its network problem, seeing how the ms is in the low 40s?

[viscid monolith]

I have 2 functions.

    UFUNCTION(Server, Reliable)
        void SetPlayerTeam(int _team);
    UFUNCTION(BlueprintCallable)
        int GetPlayerTeam();

If i will call SetPlayerTeam(), and then i would want to know team i specified from other client, will GetPlayerTeam() return team i specified?

[grizzled stirrup]

Same PC is 0 ping, when you start adding real world latency problems appear. Try testing in editor with simulated latency and packet loss and if you notice the same jitter then it's not the network and it's just your code / how the CMC corrects movement

[rotund quarry]

So it could be bad replication even though on same PC its okay? Ill have to recheck that part if thats the case

[chrome bay]

It's just that you haven't tested what you've made with latency yet

So the flaws will be showing through now

For MP you want to get into a habit of packaging up and testing stuff outside the editor in a "real" environment, but also testing in-editor with simulated lag and such

[rotund quarry]

Thank you, Ill give it a go. Probably a lot of stuff added up too that I havent considered

[chrome bay]

The editor has some built in stuff for it (look at Network Emulation Settings under Advanced Play Options) - can recommend using Clumsy.io too, that's a handy app

[silent valley]

This is good advice, we tend to always run/dev with bad network latency emulation on, then when we play online for real it's a joy to play 😄

[languid ruin]

Hi everyone, i'm having an error every time a server travel occurs, i guess the error comes from the highlighted line but don't really know how to deal with it.
Maybe it is because i moved the map and it's past location is still linked somehow but how can i fix it?

[kindred widget]

Question about C++ OnRep. Since it doesn't get called on the server. How do people normally handle that when you're looping over an array? So for instance you change five values. You wouldn't want to call the onrep five times locally. But calling it regardless of whether you changed the array or not also feels kind of dumb.

Do I just need to implement some bool checks and toggle them if I change the array and then if statement that before calling the OnRep or something?

[leaden atlas]

whats a good, easy way of doing a constantly degrading hunger meter with network prediction?

[winged badger]

@kindred widget typically server would do its stuff while setting elements on the array

client would ideally reuse that (per element) function during its OnReps

[leaden atlas]

I was thinking like maybe using a replicated timeline or roll my own implementation that just replicates network timestamps + hunger rate + hunger level or something

But idunno

[winged badger]

@leaden atlas sync network clocks, timestamp the state when you update it, and let each machine simulate the... degradation

only update from server if something forces an update outside the ticker

[kindred widget]

Nah. I literally just need to call a dispatch when the array changes at all to update some UI. I just don't want to call it five times in one function, or bother calling it if nothing changed.

[winged badger]

this leads to introducing a 2nd variable - lets call it SimulatedDelte

that you tick up/down w/e

and your GetHunger returns the (Hunger + SimulatedDelta)

that way everyone can tick their stuff without affecting the replicated variable

[leaden atlas]

kk

[winged badger]

when server chooses to update, client uses OnRep to set its value to server's and zeroes its SimulatedDelta

in its most basic form, that is the cheapest accurate way

[marble gazelle]

I'd think of using an RPC to sync the time instead of a replicated variable, since you never really know when this is getting replicated, but for RPCs you know they are sent

[leaden atlas]

🤔

[limber gyro]

the playerState constructor should runbefore a post login right?

[leaden atlas]

i dont think so but also i cant confirm

[red salmon]

Does anyone know how to set up multi user with hamachi cause I heard its possible but when I tried it but failed for me to create the server due to this error LogUdpMessaging: Error: StartTransport failed to create unicast socket on (btw I dont know where to put this question like in what room so I am gonna place it here since it has some correlation with it I guess)

[viscid monolith]

How to get other client's Player Character?

[dark edge]

From where?

[viscid monolith]

From one character to other

[dark edge]

What if there are three clients? How do you know which one you want

Anyway call me you should be able to go into game state, get the players array, then for each player, get their possessed Pawn

[viscid monolith]

Right question, im doing it for debug purpose, as im only learning multiplayer

Oh, i got it, thanks!

[worldly ore]

Hello guys

I've created a blueprint for handle websocket connections

This blueprint is an actor and create connection to backend server (node.JS) by adding this component into "PlayerController".

Now, I would push an event from UE to Node.JS server when player press a button inside a widget. But I can't access into Socket Blueprint ...

[clear sand]

So I basically can use runtime checks for development, but use #if UE_SERVER for build, to remove server code from client part, right?

[severe widget]

Editor builds and such include the server, and you can also decide at any time to enable server code in your client binaries.

in other words yes UE_SERVER works as you would expect

[clear sand]

Cool thanks

Another question - I want to persist player's location every few second to remote server. And since I want to prevent any kind of location hacking, it should be persisting from dedicated server. I've implemented this using FRunnanble, but I'm not sure how will it impact server performance, since if I get ~250ppl running on same server, and every player will generate GRPC request every few seconds - thats probably literally bury my dedicated server

What approach are ppl using to persist player's location to remote server?

[blazing bloom]

Sorry for repeating the question asked in #cpp but I realized this might be a better forum for it:

As far as you know, is UE4 capable of correctly replicating circular object references? I'm working through a bug caused by references replicated to nullptr to clients and the only unusual way about these references is that they are circular (Object A references object B and vice versa). The reference from A->B is valid but not the other way around.

[dawn ledge]

I don't think it would know or care about circular references, as long as both objects are replicated, both pointers are replicated, and the pointers are assigned by the server, I imagine it would just work

[blazing bloom]

I guess I should set up a minimal project and try it out. It's one way of ruling this out.

[steel vault]

This is a great practice when trying to reproduce possible glitches like that.

[graceful shard]

anyone happen to know off the top of their head if actors which are marked as owned by a player are automatically destroyed when that player disconnects? Or do I need to do that myself?

[muted nest]

Hi all, I have placed an actor into the map that acts sorta like a controller to remove placeholder actors in the world and adds them to a instanced static mesh component. The issue im having is i want to get all the transforms of these actors and do the work on the server then send all the transforms to the client to sync the server and client up my issue is that my transform array isn't getting sent to the client via RPC event only gets sent to the server.

Im running a dedicated server setup and reading online they say to set the owner to the player pawn or player controller but what if there is no player online? should i set this to another actor and what should that actor be?

[sharp rapids]

hiya everyone. what's the difference between "Play Offline" "Play As Listen Server" and "Play As Client" ? play as client seems obvious - the editor spawns a client and a server and connects them. play as listen server seems like it just spawns one process that is both client and server? but then what's play offline?

maybe it's that with listenserver it opens network sockets so multiple players can play but is otherwise the same as offline?

[steel vault]

Play as client implies no listen server, so basically a dedicated server where everyone is a client. Listen server means one of the clients is also the server. Play offline I believe just means there is no net driver.

Optimization question: If you have a replicated struct full of boolean values to toggle things on or off, and OnRep you want to perform an action based on if one of those booleans changed, what is the best way to optimize this? Is it more effective to replicate an array of booleans that have been set to true and compare previous to new state and take action based on if it is missing or added to the array? Or is it more effective to replicate the struct itself and somehow do a comparison to see which booleans have changed? I feel like if the struct had a ton of booleans, then iterating through them all would be less effective.

Have a sneaking suspicion I'm going to be told to finally have to use FFastArray

[versed socket]

Do you guys ever find that AGameMode::ServerTravel doesn't work in the packaged distributable? The command is disabled in PIE, but when trying it out with friends with the packaged Shipping build it doesn't seem to actually do anything, which is strange. Looking at the source implementations in the method, it's pretty clear that it should move it and all clients to the new map... but I don't see it happening in reality. I'm sure I'm not the first person to encounter this.

[chrome bay]

@steel vault depends how many you have, but you could just use a bitmask instead for up to 64 discrete values

[steel vault]

Smart. My brain is a fried egg so didn't even consider that. So basically replicate a uint8, 16, 32, or 64 and then diff it somehow?

Would love to know if anyone has a solid bit diffing algorithm

[chrome bay]

Can just use a simple for loop

[steel vault]

Ok, was just going to manually do it that way, but wasn't sure if there was any slick way to get away with not iterating each bit knowing if one hadn't changed.

I guess since it's only on rep and I can set it up so it's not running too often that it won't be much of a performance hit regardless.

[chrome bay]

Cost will be negligible next to everthing else tbh

[grizzled stirrup]

Can you call an OnRep function on the client as a regular function?

[steel vault]

I think so, but you should separate the action to its own function which is simply called from OnRep. That way you aren’t conflating things.

[grizzled stirrup]

Yeah I have been doing this but for listen server it can make things inconsistent as when an OnRep property is set I usually call it on the server right after rather than making a separate function that is called both here and via the OnRep

Just one less function call and less error prone in cases where you change what is called in the OnRep but forget to update the function called after one of the instances where the property is set on the server

Would be a no brainer on dedicated servers though

[steel vault]

I would argue it’s less error prone to be explicit with function names rather than calling a random OnRep function name. That means nothing until you see what is happening inside whereas an explicit function name makes sense.

[jaunty glen]

Does anyone known of an up to date user login tutorial for unreal? The ones I find are out of date enough where they don't work anymore. I have one which works great on the website portal but no longer seems to function inside of UE4 itself.

[grizzled stirrup]

I agree but it's just more to keep track of like "oh I'm meant to call X function on the server after Y property replicates" vs "the property replicates, both client and server will call the same exact thing guaranteed"

So if whatever is being called in the OnRep changes, it automatically updates for the server too

Without having to track down where you set the OnRep and manually change serverside function calls which can lead to errors

[steel vault]

I know some senior devs in here who would encourage you not to do this, but I will let them chime in if they want. If anything is supposed to change a server side variable then you have an explicit function that does that and you call that where needed. I know it seems like an additional step, but imo it’s best practice.

[grizzled stirrup]

Yep it is best practice and especially makes sense on dedicated servers

I just have had trouble updating things and it is a bit less clear when I'm looking at code to see what is being run where

[steel vault]

Well it is your code base in the end so do whatever works for you 🙂

But yes you can call it

[grizzled stirrup]

One other check for listen servers that I'm unsure of: is calling a ServerRPC as the host also fine to call like a normal function?

Take this example

// If the host this will call an OnRep function on clients
TimesFired++;

// If a client, tell the host to increment this int for other clients to see
if (Role < ROLE_Authority)
{
  ServerIncrementTimesFired();
}

Could I replace this with

ServerIncrementTimesFired();

And get the same result?

Since if host it'll call the RPC function "for free" and replicate the int and if client it'll do a server RPC which will replicate

[steel vault]

Im not at my computer so I don’t have the link but I believe that if it is calling from where it is already supposed to be it falls through and just executes without making a network call so that should be fine, but again, there is nothing wrong with being explicit.

Make things operate how they should without fudging things just because they work.

[grizzled stirrup]

So you'd go with the first option in this case?

[steel vault]

I personally make a separate function and call it from within the server ufunction. Logic goes in functions and the server function is obviously reserved for executing logic on the server.

But I believe you can still just call the server function even if you are the server

[grizzled stirrup]

So it'd be like:

// If the host this will call an OnRep function on clients
if (GetLocalRole() == ROLE_Authority)
{
  IncrementTimesFired();
}
else
{
  // Calls IncrementTimesFired() on the Server
  ServerIncrementTimesFired();
}

[steel vault]

Yes 👍🏻

[grizzled stirrup]

Thanks!

[steel vault]

If you want an argument in favor of that method it would be because if the client functionality varies slightly and something server specific happens in the server function that doesnt effect the core increment functionality then they are separate. Compartmentalizing functionality future proofs things better.

Also I think there is a better check for the server. GetNetMode == ENetMode::ListenServer etc.

[terse prawn]

Can the server set a client's control rotation via a reference to the controller? or does the client have to update that themselves?

[versed socket]

Reposting from earlier:

Do you guys ever find that AGameMode::ServerTravel doesn't work in the packaged distributable? The command is disabled in PIE, but when trying it out with friends with the packaged Shipping build it doesn't seem to actually do anything, which is strange. Looking at the source implementations in the method, it's pretty clear that it should move it and all clients to the new map... but I don't see it happening in reality. I'm sure I'm not the first person to encounter this.

The documentation says that we should just call ServerTravel and it will "work", though that's not reality for me. I even have Level Streaming disabled, so that it doesn't get short circuited in the implementation.

[winged badger]

steam sockets won't really work with hard travel

you have to toggle seamless

[rustic adder]

hey there, Im using advanced steam sessions. Ive successfully hosted a dedi server
I try to connect to the server using the command open 127.0.0.1 and this is the result. Will not connect
also, find advanced sessions gives me nothing

[chrome pagoda]

For character respawning do people typically destroy and create actors or just try to reset and reposition a player's actor?

[twin juniper]

Depends on setup, generally you can destroy the pawn and you keep things specific to the player but not the player character elsewhere, eg in the player state.

Destroying pawn is a bit less messy if theres loads of variables you need to reset as if you create a new one they will automatically return to default.

Just be sure when you destroy it you have nothing running that depends on on it being alive or you will get 'pending kill' error.

[languid ruin]

Gotta repost guys i'm hard stuck, and i really don't know why: anytime i try a server travel (with seamless travel unabled in gamemode) on standalone or via launch game, the game crashes rightaway

[winged badger]

@rustic adder steam API limitation: you won't be able to see a server hosted from a same machine you're searching from

@languid ruin i'd expect a callstack attached to that problem

most likely scenario, your UI should had been cleaned up prior to travel, but wasn't

and if you're expecting a fine control of seamless travel from blueprints, you're out of luck really

rudimentary use of c++ can help tons

[languid ruin]

you mean i have to remove any widgets from viewport before doing so? also is it possible to quickly provide my blueprint with a c++ server travel equivalent?

[winged badger]

not all

some can survive travel and be visible on the other side

but ones that depend on say LobbyController or LobbyHUD being there

when your game switches to PlayController or PlayHUD

those will crash

depends on the widget really

UE crash reporter told you exactly where the problem is

(provided you have debugging symbols installed)

[languid ruin]

no i'll donwload it in a few hours

[winged badger]

try reposting when you do, because 1000 different things could had crashed

and without that callstack, everything else is just guessing

UI not cleaned is just the most common scenario, far from only one

[languid ruin]

i see, thank you really for the help, i just have one more question: do PControllers persist after a server travel?

[winged badger]

they do if you're setup correctly for it

its best to have the travel map run the same GameMode as the departing map

[languid ruin]

Okay, first I'll try to get the Server Travel working on Bluerprint and then maybe i'll try C++ if I have the time

[languid ruin]

yes i figured that out

[winged badger]

problem with blueprints is you don't have hooks like

void APlayerController::PreClientTravel( const FString& PendingURL, ETravelType TravelType, bool bIsSeamlessTravel )
{
    UGameInstance* GameInstance = GetGameInstance();
    if (GameInstance)
    {
        GameInstance->NotifyPreClientTravel(PendingURL, TravelType, bIsSeamlessTravel);
    }
}

which is typically used to clean up everything that shouldn't come along for the ride

UI is the most common offender because it is not tied into World

but into Viewport, which is tied to LocalPlayer, which is tied to GameInstance

so it usually doesn't get autodestroyed with the departing world

[languid ruin]

Alright, thank you again for all the intel, I'll get some sleep before trying this

[winged badger]

good luck

[forest sage]

My steam dedicated server is not listed in the client server browser. Though if i add it manually it is shown as active, with ping and player count. Using python-valve i get it's address from the steam master server. Is it not listed by default because the game is not released yet? Or did i miss anything else?

[mortal kernel]

Hey there... I'm not sure what I do wrong but I'm trying to have every connected player inside a Box... but it just won't work out... not sure how to do it

[winged badger]

@forest sage same machine running the dedi and client?

[forest sage]

@winged badger Nope, dedicated is running on a dedicated machine in the Internet.

[surreal plaza]

How does UE handle replication when components are attached? Does it just replicate all child object transforms separately?

[chrome bay]

yeah. the component itself has the be replicated though.

See USceneComponent::GetLifetimeReplicatedProps

[potent furnace]

Hi! 🙂
I'm making a multiplayer game and I have problem with replicating movement with GetCharacterMovement()->AddForce(). When I use AddMovementInput() replication is working properly.

When I set my function like this - UFUNCTION(Server, Reliable), when server player moves, all client players are moving with him. When I play for client, everything works fine.

When I set my function like this - UFUNCTION(Client, Reliable), server player is still moving with all players but clients players can't moving themselfes anymore.

After few days of googling and trying to solve it I found only one solution (you can see it in screenshot), but I don't think this is the best practice. Guys, can you please help me out?

[surreal plaza]

Jambox, how does this change for attached actors? If I have 2 replicated actors and attach one to the other. If I move the parent, does the local machine handle the translation of the child object or is done directly?

[surreal plaza]

Let me give you better context. I am working on a battlebot type game, where characters, on the fly, can design new robots, each of which could contain up to say 50 individual components. And these are made on the fly, so characters can have multiple in play at the same time. I am trying to minimize the bandwidth damage from that. If you think of most of the child components of a given bot, they are just following the parent around until they activate in some form (fire, flip over, etc).

[surreal plaza]

Would child actors be a better option here? Or would the cost of the replication be essentially the same?

[winged badger]

@potent furnace you want a IsLocallyControlled check in combination with a server function

also, never ignore the log warnings of "no owning player for connection..." that you have tons of right now

[woeful ferry]

Is OnRep exceptionally buggy in 4.26 or is it multiplayer in PIE that is? I have one component that is incredible messy in certain actors in terms of not firing OnRep, and I haven't changed any logic related to the component.

I heard from Zlo yesterday that there's a bug regarding OnRep. That if you only have one replicated variable, it won't fire OnRep.

[winged badger]

c++ only

[woeful ferry]

Yes, this is in c++

[winged badger]

and i doubt they extra broke OnReps in 4.26

even if i have heard 4.26 described as "critical bug package"

[chrome bay]

@surreal plaza On an actor, if you replicate movement then that is handled separately via AttachmentReplication

Unless you are changing the component's attachments from their defaults then you shouldn't need to replicate anything else

child actors for components are just going to have even more overhead tbh, because that's a totally separate channel then

[winged badger]

child actors are likely to break in more ways then one

not really MP friendly

[surreal plaza]

I believe I would be changing the attachments from defaults. So imagine you are in front of a workbench with a robot torso. This would be in game. You throw 2 tank treads on it, then a cannon, and a flip mechanism and immediately throw it into the ring.

[surreal plaza]

Those configurations are always ad hoc and not an instantiated blueprint of any kind.

[chrome bay]

Ultimately if you want to attach components to other components then yeah you need to replicate their individual attachements

the "easy" way is just mark the component itself as replicated and the default properties will handle it

But tbh, you could probably build something more bespoke that handles your case better

[surreal plaza]

And each component has it's own mesh, blueprint for behavior, sounds, and animation.

[chrome bay]

well only properties you mark as replicated will be replicated

[surreal plaza]

Let me clarify. Each robot part has all of those things. I am overusing 'component'

[chrome bay]

Are your different robot "pieces" actors or components?

In the Unreal sense

[surreal plaza]

That is where I am headed. Likely actors. They are robust in their own right. So if I add a 'gun' piece, it might have a unique UI for parameters for that particular robot. Like, caliber or something.

[chrome bay]

Right

So if you want the easy way, just check "bReplicateMovement"

and whatever you attach the actor too server-side will replicate and be handled by the client

[potent furnace]

Ok, could you maybe say a little more about a solution, I'm sorry, but I'm still new to multiplayer in UE4. So I would define my movement function like this?
UFUNCTION(Server, Reliable) PlayerMovement(float value);

When I set PlayerMovement like server function and when I add if condition to PlayerMovement (you can see it in screesnot) server player is moving all players, clients are moving themselfes and only server player is "true" for my if (IsLocallyControlled()) condition.

[winged badger]

always paste the function header

cant say where that is

i suspect you're doing something unspeakable, along the lines of checking on Tick from each Character if Controller[0] has a key pressed and applying force

[chrome bay]

@surreal plaza each actor will replicate it's attach parent individually, if that's what you're asking

Then assuming it's relative transform doesn't change, it won't replicate anything else - but the properties will still be checked server side.

[surreal plaza]

So, I have TorsoActor (brep = true) and GunActor(brep=true) and attach GunActor to TorsoActor. Is that right? That sounds like it works, but maybe the most expensive bandwidth wise. The other direction I was considering was that

TorsoActor(brep = true)
GunActor (brep = false) <--- but still instantiate this on all clients
Attach GunActor to TorsoActor.

But! Now GunActor isn't replicated! But maybe I don't care if it is just a visual indicator but the ultimate actions (flipping, firing, etc) are still spawned and managed server side. Does that make sense?

[chrome bay]

that's just asking for trouble tbh

because you won't be able to do anything involving GunActor and the network then, you won't even be able to reference it

[surreal plaza]

I think you just answered my question. If the relative transform doesn't change, most of the time only the parent transformation data will cross the wire and I won't have 50+ actor content replicating.

[chrome bay]

The easy way to answer it is just look at AActor::GatherMovement and see what it does

if it's attached to something, it uses AttachmentReplication

if it's not, it uses ReplicatedMovement

[surreal plaza]

Right on. I will do that. I am digging into the network profiler too.

[chrome bay]

AttachmentReplication is presumed to be relative

[surreal plaza]

Great. It is almost like smart guys put this all together.

[chrome bay]

So if after attaching the relative location/rotation etc. doesn't change, then no other data will be sent - just the root actor's transform will be the thing replicating

At the same time though, the Server is still going to be testing those actors' properties each network frame

So if you wanted to claw some of that back, you could make your own attachment hierarchy that only replicates once at startup for example stored on the base actor

Lots of ways of doing it I guess

[surreal plaza]

Right. That is where I was prematurely optimizing. I was working on encoding/serializing the robot description into a string and then synchronizing that, but like you mentioned before, that leaves me with disconnected actors. I am not sure that I am following where in our discussed scenarios that 'my own attachment hierarchy' would fall. Wouldn't rolling my own hierarchy just not take advantage of attachment replication ignoring relative stillness?

[surreal plaza]

I am working if this is possible with a chain of objects.

A brep=true
B brep=true
C brep=true

C attaches to B, B attaches to A. If I move A will C replicate?

[chrome bay]

Nothing will replicate if it's attached, it's attached so it will just move with it's parent

[surreal plaza]

It looks like this works. I wasn't trying to describe circular, just multiple levels deep.

[surreal plaza]

So just so I understand this fully. Even though child transform might be stationary and not sent on the frame, if the parent moves the world coordinate change is handled on the local machine and that all works out.

[surreal plaza]

And this is all done via AActor::AttachToActor.

[chrome bay]

You're overthinking it. No transform is replicating on the child if you move the base

The base transform change is the only thing that replicates any data

Things that are attached to it just naturally updated like any regular attachment would

[surreal plaza]

That is what I meant to say by 'not sent on the frame.' If I did move the child on a given frame, it would get a replicated transform for just that frame. Otherwise, the parent just carries it locally. Right?

[surreal plaza]

Thanks a bunch, btw. This has answered a great deal of questions and confusion I had.

[chrome bay]

Yeah that's it

[grave notch]

Anyone tried network prediction plugin? (its official plugin)

v0.1 beta

[eternal canyon]

yes

I have

[grave notch]

is it useful?

[eternal canyon]

not for my use case

tho from what i can see

it looked as if in the examples that it would smooth the movement on otehr clients (interp) and showed off replicating pawn flying movement component

and replicated physics

that were smooth

tho I could be wrong about some stuff

[grave notch]

okay, ty

[potent cradle]

There's certain times when I want to make sure that a multicast hits every single connected instance of an actor, in which case I set to always relevant before the MC, and then turn it back off after.

Should I wait for a duration in between? Or is Unreal smart enough to notice that the MC happened in the span when it was set to always relevant?

(Granted, maybe I should rethink this entire strategy, but would like to understand how it behaves with the above steps)

[silent valley]

I doubt that would work, the Actor won't even exist for some clients when you call the RPC. It takes time for the Actor to replicate to all clients.

[potent cradle]

That's a good point 🤔

I think I'll go with a repnotify instead, rethink the flow a bit

[chrome bay]

always vars for state

[west condor]

Has anyone done volume based game session merging?

Wanting to create a single/multi player hybrid based on that

[woeful ferry]

@winged badger I found the issue for the OnRep function.

Apparently I had set the resize of the inventory array outside a HasAuthority check on BeginPlay. Still don't understand why the OnRep would fire on some actors and some not though, that is outside of my knowledge of how networking is being handled

[sick yew]

Is there another way to go about replicating whole skill lines like this or do I have to essentially just have the skill twice with the replicated components? Just want to make sure I am doing it the most efficient way.

[vocal cargo]

hey guys, does anyone know what's a good way of handling characters on top of replicated pawns?

I have some very visible jitter

Is attaching OnLanded the way to go in these situations?

[weary badge]

Is there a way for the Game Mode to call an event on all the player controllers simultaneously ?
If I use for each loop, it creates a delay, that I'd like to avoid
(the project is blueprint only)

[languid ruin]

Here's the callstack, I still don't get where the error comes from tho

[leaden atlas]

is there a way to do replication outside of AActor?

i want to do a simple chat system that's outside of the game logic classes

and i was wondering if its possible to put it into like a game instance subsystem or something. some sorta global

[steel vault]

This usually means you are calling -> on a null pointer.

[leaden atlas]

hmmm i see stuff with UChannel

[languid ruin]

I guess there is no way to find out in which blueprint the error comes from?

[floral crow]

Has anyone used Unreal Insights and, more specifically, Network Insights successfully? Is it reliable enough to replace the Network Profiler tool?

Talking about this: https://docs.unrealengine.com/en-US/TestingAndOptimization/PerformanceAndProfiling/UnrealInsights/NetworkingInsights/index.html

I've just found out about it but it is still experimental. Is this live-coding type of experimental (e.g. already better than Network Profiler but not finished yet)?

Can it cause any sort of corruption in my project if I use it?

[meager spade]

it works, its better than network profiler, and why would it cause corruptions?

[halcyon pilot]

If everything in the Anim BP is inherently replicated why not put all the animations in the anim BP that you can and then call them from the character BP/PC?

[floral crow]

I don't know. I've been bitten too many times by corruption to the point I fear it at every other step I make 😅

I finally got it to work, I'll ask any questions if I need so. Thanks @meager spade

[wheat magnet]

emitter is not spawning and showing in client side, what cause the issue?

i already doing RPC, but why this happens?

[thin stratus]

Why are both the Emitter and Template replicated if you already multicast?
And where is that code located in? Is it even client owned? Otherwise it won't execute the ServerRPC

[wheat magnet]

it working now without doing anything, i think making these functions reliable fixed the issue

[dark edge]

It might make it work but that's a very bad design. Reliable rpcs for a particle effect is a surefire way to clog up your pipe.

[meager spade]

^

then again i always send a reliable client rpc back on sucessful hits, like what this is for, but its never multicasted reliable, them sort of things are unreliable. but the important stuff back to the client is always via a reliable rpc, unless it was a failed hit, that comes back via a unreliable rpc, cause not bothered if client does not get that.

[dawn glen]

If i set up a game with basic multiplayer where the client is also the server, then want to build out a dedicated server, will all the stuff the server client uses get automatically disabled or do i have to check for dedicated server everywhere i deal with UI and player movement and such to bypass it myself?

[kindred widget]

@dawn glen If you do your programming correctly, there won't really be a difference between a ListenServer or Dedicated Server. I've been working under the pretense of Listenserver uses, but kept in mind that I may one day change to a dedicated setup. You can very easily separate your server logic from the hosting client's client logic so that when you do change to dedicated, nothing should change except that one client will no longer also be host.

[leaden atlas]

is it possible to predict uobject or aactor creation?

like do it on the client before it happens on the server

[finite kettle]

It is, but you gonna have "good" times with net pairing client side's actor and server side's actor (to get replication working)

[meager spade]

no

you can't predict what the server is going to do, prediction can only happen if the client tells the server its going to do X

[finite kettle]

I'd say he means exactly the case you're describing, at least that's how I understood it

[meager spade]

yeah cause the client could never know what the server was intending without the server telling it, and that is not really prediction 😄

[dawn glen]

@kindred widget I thought it would cause errors and such if you launched a Dedicated when it was designed as a client server when it would try and run the Widget stuff or cast to player controllers. So i know you can kinda easily put in branch checks for dedicated server and bypass all of that but i guess my question was do i have to?

[leaden atlas]

yeah thats what i mean

im doing an inventory system using uobjects

and i want to predict item pickup/creation or whatever

[meager spade]

oh that is one thing i never predict in a multiplayer game

nor have i seen many games do that

even big games like Fortnite don't predict pickups

nothing is going to be more frustrating than thinking you have an item, and server nabs it away from you

[leaden atlas]

hmm okay

i guess i really dont need this sorta feature

[meager spade]

imagine like the best item in the game on the floor, 3 people interact with it as soon as they see it, only 1 person is going to get it but all 3 people think they have it

till server rejects 2 of them, that would be bad for those players

[leaden atlas]

good point

[meager spade]

i always have in my mind, predict as little as possible to make the game feel responsive

you can play the pickup animation/act like your picking it up locally

(which is what big games do)

[dawn glen]

Thats one thing i havent thought about yet is "duping" If an item is on the ground and you dont handle it right, the 3 people will pick it up at the same time and all 3 get it.

And how should one best handle that? I suppose i would hit the pickup button and then send my look vector to the server to do the trace to the object?

[leaden atlas]

I think you should just let the client tell you what it hit

And then just perform checks to make sure it's not too far away or behind a wall or w/e

[plain torrent]

Is it possible to connect to my teammates on a simulated project with steam appid 480? Or do I need to purchase our application before we can really start integrating steam functionality like connecting VIA steam friendslist?

[stuck acorn]

Hello everyone... I have a problem with creating a simple multiplayer game for mobile devices. Like Multiplayer Shootout project sample i made a menu for hosting and joining game. Hosting section works good and session created successfully with Use LAN enabled and level opened with listen option and everything is good. but problem is here when other device wants to find session, i made a menu for that and i know Find Sessions node run On Success but there is not any sessions found !!

[grave notch]

Why ue4 doesnt have sql/any db support by default, isnt it common thing? Im not sure should i use rest api through https to work with db, or make db access in ur4 server side (for dedicated server)?

[marble gazelle]

We use a rest service / swapping to a stomp client to do requests to our backend, actually that's really cool, since you can swap your backend as you wish

[winged badger]

@plain torrent i'd advise buying the steam ID, its 100$

[plain torrent]

I was suspecting that would be the answer! Thank you 🙂

[winged badger]

it just provides too many conveniences to screw around with appid 480

you can add the teammates as devs

[plain torrent]

I don't suppose there's any alternatives to the 100$ license?

[winged badger]

then they can upload and deploy builds themselves

[plain torrent]

Such as education etc?

[winged badger]

and they automatically "own" the game

i have no idea, my project is commercial

[plain torrent]

If this is just an early working title, can I buy a single appid and re-use it if this project get scrapped?

[winged badger]

but just being able to deploy a packaged version via steam is already significantly improving the workflow

i don't see why not

and you do get that money back if you sell few hundred bucks worth of game

[plain torrent]

Oh interesting, i wasn't aware of that

I'll definitely have to get that application going I suppose. How long does it take to get an app id?

[winged badger]

few days i think

[plain torrent]

And the prime reason we want this is to be able to start debugging steam p2p. Is this the best solution for that, or is there something else you may be able to suggest? I really appreciate your help!

[winged badger]

with your own app Id you can deploy multiple builds, packaged DebugGame configuration is pretty good for debugging

as you get to use the cheat manager, set console variables, slow down the game, use GameplayDebugger, "eject" into a debug camera.... etc

[plain torrent]

I'll add that to the budget request! thanks for your help 🙂

[dawn nova]

Does anyone know if TSet supports replication in 4.23?

[chrome bay]

Only TArray

[dawn nova]

Alright, thanks for the quick answer

[plain torrent]

@winged badger May be me being really silly, but I can't find the page to begin the application for our App ID? 😆

[unkempt wind]

Hi everyone! I'm developing a strategy game and I'm looking for a strategic advice. Currently I'm leveraging Linux cross-compilation to build the dedicated server, then I dockerize and deploy it on Google Cloud. It works like a charm, anything that works on Windows works on Linux as well. So much that I didn't even have to set up a dev environment on Linux.
But I know that at some point I might get into trouble. So I'd like to know what is the common practice in the industry and the most traveled path. Are dedicated server most commonly built on Windows or Linux?
I have little experience with UE and I don't know the behind-the-scene and the quality of Linux support. What do you suggest?

[dark edge]

If you are serious about it, I would at least whip up a little Linux box for testing. But if it works it works.

[plain torrent]

Hey everyone sorry to bother again.. We use Digital Ocean to host our Perforce, has anyone used Digital Ocean to host a UE Dedicated Server, and if so, how hard was it to get that setup?

[unkempt wind]

Yeah, I know that mine might seem an odd question. But I've realized that some plugins don't support Linux, so I'm wondering how common the practice of building a Linux dedicated server is. For me that was a natural choice, but honestly if the wind blows in opposite direction and 90% of studios are using Windows, then I won't choose the hard path

For example, it might be helpful to know which OS Epic chose for its own games

[dark edge]

I'm not sure but I would bet million bucks that they are running their dedicated servers on Linux.

[dark edge]

Easy. There's nothing special about your choice of hosting provider for a test server. It might come in to play for an automated deployment though.

I host my perforce, ue4 test server, and valheim server all on the same machine cuz YOLO

[plain torrent]

Ahh I see, so I just go through the steps of compiling the source code and uploading it to a linux server?

[dark edge]

For testing I just have a compiled engine on the Linux box and it just fires up the project as a headless server, so no building anything every time the project changes.

[plain torrent]

I'm saving up old parts to build a Frankenstein server system, not long now

Do I need to pull the full release build from git if we're working on 4.26.1?

[dark edge]

I don't know if 4.26.1 is currently released but if it is, that should work. Just make sure you're on the same version. I'm not sure if there's any problems between devving on the launcher version and running the Linux side on the built version

[plain torrent]

thanks, I'm downloading 4.26 now. fingers crossed all goes well

[twin juniper]

In what blueprint should I handle win conditions for an online multiplayer game?

Should I create a custom game state (child of AGameStateBase) and use that, so it's exposed to BP?

reading about it looks like game mode better for that

[meager spade]

Win condition is in GameMode

GameMode should control the game flow (its server only and secure)

[twin juniper]

Thanks, but why use game state at all then?

I'm looking at documentation, it says to use Game State for stuff relevant to all players because it's replicated I guess, so maybe if player A scores a point, it gets updated in the game mode, then a variable is also updated in game state mirroring the game mode variable (but not determining win/loss), then the player HUD accesses game state or something for score display? I guess that would also stop players cheating by setting their own scores but couldn't they also 'cheat' by adjusting their displayed score, confusing other players, even if it doesn't help them win?

[meager spade]

GameState is for things that all players should know about the state of the current game

GameMode should update the GameState when conditions are met

[twin juniper]

Well I want players to know the scores of every other player. I guess I should have two copies of the scores of each player: one in the game mode and one in the game state. They are the same except the game mode one ends the game when certain conditions on the score are met.

[kindred widget]

@twin juniper That's a lot of upkeep, and prone to bugs if you forget to update one or the other. Just make your GameMode get variables from the server's GameState.

[eternal citrus]

guys I have screen space widget that acts as nameplate for my character

but in multiplayer

clients sometimes don't see it

well actually most of the time

but when I switch it from screen space to world space it does not disappear

why is that?

and how can I fix it?

[twin juniper]

Is 'playerID' different from 'controllerID'?

[surreal plaza]

I am getting started with network profiling in UE. Is the network profiler still relevant or has everything moved to Insights?

[dense ocean]

My client can't see replicated movement until about 10 seconds after starting my standalone game, for the first 10 seconds he can only see client events, then all replicated movement of other players snaps to where it should be after that 10 seconds. Anyone know how i can fix this?

I'm opening my unreal project twice on my PC to represent each client, can that be causing the issue?

[kindred widget]

@dense ocean How large is the project? How much is being replicated at the start of game?

[dense ocean]

It's very small, been happening since I just started it

[rich ridge]

You know you can open two clients from single instance of editor.

[dense ocean]

I don't believe I can open two standalone games though, I'm using Servertravel to go from a lobby to a game map, and I was told that you can't use servertravel in PIE

If there is a way to do this from one instance of the editor it would be a life changer for me lol

[kindred widget]

Hmm. not sure then. Might not fix your issue, but I had a similar problem when I started replicating foliage stuff. Even if it doesn't fix it, you might want to make it a habit to drop this into your Project's DefaultEngine.ini when starting a new multiplayer project if you don't already.

ConfiguredInternetSpeed=1000000
ConfiguredLanSpeed=1000000

[/Script/OnlineSubsystemUtils.IpNetDriver]
MaxClientRate=1000000
MaxInternetClientRate=1000000```

[rich ridge]

can you point me to that message, which says PIE can't to server travel?

[dense ocean]

It was a long time ago, i never looked deeper into it after that @rich ridge but I am very open and ready to do some testing as I believe it's probably just a setting i need to change regarding seamless travel, or maybe something in my config. I doubt unreal would ever require you to open multiple editors to test multiplayer

[rich ridge]

set players as 2 or 3 or 10...

so editor will launch those many clients

[dense ocean]

Thank you very much, I'll give it a go. I should also add, after that time period the client stays where they were, even if the server used SetActorLocation. Only after the 10 seconds, when the client JUMPS they are moved to where the server previously tried to move them to

Thank you @rich ridge Ill give it a shot soon

[rich ridge]

and also one more point to remeber, when testing multiplayer in editor for multiple clients.. always uncheck this option

[dense ocean]

Thanks very much ill do that

my settings look different

I don't have net mode

[rich ridge]

@dense ocean By default all clients will run under one process and will share memory and most of the RPC and replication logic will work fine, when you actually try to test stand alone things wont work

[dense ocean]

using 4.24

[rich ridge]

i think 4.24 is pretty same to 4.26 in terms of multiple clients within editor

[dense ocean]

Hmmm im unsure why I can't run standalone with multiple clients

I set my num players to 2 as you can see, but when i launch Standalone only one standalone window opens

Instead of 2

[rich ridge]

it should open two

[dense ocean]

Then i guess there is my problem

[rich ridge]

try to do in fresh Third person project

[dense ocean]

Okay i will now

It works, in 4.25

I'll try in 4.24

I'm having trouble launching ue4 in 4.24, it seems i just need to update

I'm going to run to the store while i install 4.26, ill let you both know if my issues resolve after, thank you for your help

[twin juniper]

how do I end match properly in multiplayer? My print string is firing at the end of the round (when a player wins the multiplayer vs game) when I want but apparently the 'end match' node (I know its not connected lol) just puts 'MatchState' into 'Waiting::PostMatch', how do I proceed, do I need C++?

[finite goblet]

What is the reason behind having game mode not replicated? Is it a design only decision to keep rules and data separate or is there some more serious underlying technical reason?

[unkempt tiger]

it's a design choice, there shouldn't be any technical reason

it also works a lot with players through refs to their player controllers which arent replicated to other clients

If I want to net-quantize my float (to make sure it matches the net-serialized version, precision wise) can I do something like this?

It seems like this should work, albeit a hack, wondering if there's a better way to net quantize floats?

[finite goblet]

Why though?

[bronze arch]

Fellas, who will take owner of that object by destroying an object on the map from the server authority? Is it to an entire separate client or a single client?

[chrome pagoda]

If it's replicated won't destroying it on the server destroy it everywhere?

[bronze arch]

no isnt replicated(as replicated its expected but this non-replicated)

just have on the map, so server and clients will load it, when i put the begin play in to authority test, the servers has authority and clients are remote. So when destroying on server, then who will take the authority?

[chrome pagoda]

That's a good question. You could test it by interacting with it after being destroyed on the server.

[bronze arch]

i tried, but still the "switch has authority" says clients are remote. no one authority. like it falls in to space

https://tenor.com/view/sechi-youtube-cat-thinking-thoughts-gif-18698282

im atm:

[chrome pagoda]

lol

I guess it's technically correct as the thing wasn't created by the clients. When deleting it you would probably want to run it as a multicast event so clients delete it locally too.

[bronze arch]

well the grasses only no needed on the server, so i dont wanna delete on the clients as they can see grass

i was just avoididng cpu usage on grass BP on server

more weirdly, those client functions work as like authority even they are remote

[chrome pagoda]

Are you trying to set the server up as a dedicated server?

[potent cradle]

Is there a logical reason why a RepNotify within the PlayerState would not be run on the client?

It runs fine on the server, though. But I don't see it trigger on the client

EDIT: Probably because there was no actual change in the variable's value. Cleared it properly first, fixed 🙂

[bronze arch]

yes

[chrome pagoda]

https://docs.unrealengine.com/en-US/InteractiveExperiences/Networking/HowTo/DedicatedServers/index.html

You should be able to set up your dedicated server to run with no actual graphic output.

[bronze arch]

i know, i mean the grass blueprint will load as far as stay in the map. it doesnt matter graphic output

[round star]

It's my understanding that a dedicated server can also help with performance because any number of calculations that need to be done are on the server, and the result is only replicated to clients

[chrome pagoda]

So if I understand correctly you want to delete certain actors on just the server for small performance gains? Nobody is actually playing the game as the server?

[bronze arch]

No, server just sending acks, variable changes or movements only, so why should keep grass on server tho? also memory reduction affect too.

[chrome pagoda]

Sounds like it could work if you don't need the actors for anything. Might be a headache to manage depending on the type of game you're making. You could have clients load the actors locally and never load them on the server in the first place.

Easiest way would probably be level streaming, but there are probably others I'm not thinking of.

[bronze arch]

Well, i've already changed my mind way to go. So now i have no trouble about this for now.

[round star]

Can I change the net update frequency of actors on a per player basis

depending on how close they are to something

In some cases I don't want to turn it off completely..it still needs to be replicated from afar, but I don't want to send nearly as many updates

[peak sentinel]

Anyone analyzed UT source code before? I am trying to solve why they are created a new FRepUTMovement and doubled the OnRep. In the comments it says its more effective but I couldnt understand why it would be

Also same for every UT copy of usual engine functions

GatherUTMovement (calls GatherCurrentMovement() inside) etc

[peak sentinel]

From what I understand from this I should not mess with default engine functions for movement replication

[plain torrent]

Can anyone recommend a cheap VPS host for a dedicated server that's got an intuitive setup with UE?

[dawn nova]

For a cheap (but good) VPS host I can recommend Namecheap, I don't think it has integrated setup with UE though

[plain torrent]

Thanks! Do you know if the 2cpu cores and 2gb ram would be enough for a headless server, hosting 4 people max concurrent for play testing?

[lament sinew]

there's also playfab and gamelift. They provide trials right ?

[plain torrent]

My teams testing on appid 480, we're finding eachothers sessions when launching VIA steam, it's pulling his server name and when we try to join, we're getting through on success on our Join Session node, but it then doesn't connect to the server. Everything works fine on LAN. Does anyone know what could be causing this? Our default subsystems are set to steam etc

[kindred widget]

I'm under the presumption that all of these do the same thing. At least I understand that the actor component version of GetNetMode more or less gets it's actor and calls it's GetNetMode. But what is the difference with AActor and UWorld's GetNetMode? Why doesn't AActor's InternalGetNetMode function just call GetNetMode on World? It already gets world before doing the net driver thing anyhow?

Just mostly wondering if there's a reason for this to behave differently somewhere or if they'll act identical.

[winged badger]

im not convinced they behave differencly @kindred widget

Actor can get the NetMode via World or via its ActorChannel

i think

but different implementation might just be epic being sloppy

plenty of that going around in GameFramework

[kindred widget]

Kay. I'll just treat them the same way. Just wanted a sanity check. I'm a lazy person. I'd have just made AActor call UWorld's GetNetMode and been done with it. 🤷‍♂️

[dawn nova]

Hey guys, is it possible to replicate UPROPERTYs on interfaces on the interface itself? Or would I have to add it to the DoRepLifeTimes of the child actors?

[kindred widget]

I don't think you're supposed to do networking with interfaces. They're just a way for actors to communicate without casting per machine.

[dawn nova]

Yeah true, traditionally interfaces are not meant to have properties on them, just checking that maybe since they are artificial interfaces they had support for that

[kindred widget]

Out of my area there. Haven't used them past the basics.

[marble gazelle]

Shouldn't UHT complain if you add UPROPERTYs to an Interface?

[chrome bay]

It will, can't have 'em

[steel vault]

Please let me know if/when you figure this out. I haven't been able to properly server travel a steam client to the steam listen server for a long time and I have gotten exactly to the point you have. It succeeds the join after finding the host session in a search using app id 480, but doesn't server travel when doing the join. I saw examples that prove you can just run the join session and it travels automatically, but this hasn't been working for me. It just stays in the lobby until it times out.

[chrome pagoda]

From what I understand it's best practice to handle respawn stuff in a gamemode bp. How exactly do you communicate to it that it's time to respawn a client? Am I able to create an event dispatcher for that?

[rich ridge]

run a timer (on server) and loop it and in every loop spawn actors on server and it will reflect on clients too.

[kindred widget]

Eh? Why not just call RestartPlayer?

Called on GameMode, takes a PlayerController object input. You can call that when you're ready to spawn the player's pawn for respawning.

@chrome pagoda You are just trying to basically be able to kill off the player's character, and then respawn it as if when you open a new game?

[chrome pagoda]

That sounds like what I'm looking for. Will need to test when I'm working on it next.

[oak hill]

Hi guys, what would be the correct approach to replicate a variable only to specific clients? None of the lifetime conditions seems good for my case and I'm trying to avoid multicast

[chrome bay]

You can't do selective replication of variables

The only solution for a variable would be a different actor which is only relevant to those clients.

[winged badger]

you can replicate actor only to some clients though @oak hill @chrome bay

yeah, sorry, you kinda said that 😄

[kindred widget]

How do you do that, by the way? I know PlayerController does it. Never got intrigued enough to look into it.

[winged badger]

player controller is only relevant to owner

basically, override IsNetRelevantFor

or put it into some buckets in replication graph only

[kindred widget]

Ah. Neat. I assume that a good way to handle this is like.. returning a bool based on the controllers the actor should be relevant for? I might mess around with that sometime.

[oak hill]

Sounds interesting... any place where can I find more info on the replication graph?

I think I need some more control than the IsNetRelevantFor function

[winged badger]

i have no idea, there are probably some sparse docs, some semi-useful youtube videos and a blog or two about it

[oak hill]

Basically I need a specific actor to be replicated the normaly way, but only some variable need to be replicated to specific clients

[winged badger]

we went to custom push model before repgraph came in

so never went around implementing the thing

no

entire actor or no actor

repgraph or not

[oak hill]

are you talking about unreal push model?

[winged badger]

you can't pick and choose what variables inside 1 actor go to which client

you can just pick which actors in their entirety go to which clients

[oak hill]

oh, so I cannot do that with replication graph either

[winged badger]

only way you can do it is by rewriting 80% of the low level networking in the engine

do not recommend that

[oak hill]

definitely not XD

[winged badger]

literally, idea goes against the core structure of the unreal networking

[oak hill]

so I think the only way is to rewrite my logic in another way

[kindred widget]

Only semi manageable way I could see handling that is a terrible reroute through controllers. Set the value on the server, and in the set function, use the desired client's controller to RPC that change to the client. I feel dirty even mentioning that idea though.

[winged badger]

you can spawn another actor

to carry that data

and make it relevant only to some

its less messy

[kindred widget]

Why do you need only one client to have said info, but for the actor to exist on all?

[oak hill]

you mean by overriding IsNetRelevantFor?

[winged badger]

btw, @oak hill good part of pvp team setups

will have a single team actor per team

that replicates only to their team

it will override IsNetRElevantFor

to cast rel viewer to controller, pull the team ID from the controller and return false if the controllers team ID does not match its own

im guessing you want something like that

[oak hill]

not really

basically I need a generic actor that is visible to anyone, but only some players can use and receive its data

but players aren't part of any team

maybe a solution could be to store an array of these players in the actor itself and use client RPC, but I was asking to know if there was some method that works in this situation by using replicated variables

[winged badger]

nope, unreal replication will send the entire replicated actor to all relevant clients at the same time

[oak hill]

ok, thank you for the clarifications

[signal lance]

Pretty sure ue4 replication sees what has changed since last replication, serializes it into a package and and sends it to all relevant players
So it would be pretty much impossible with the current system to do partial replication for specific players, maybe with custom net serializers you could have the client discard the data when it receives if it's not the correct one but that's a workaround and not sure how useful would be for your use case since the server is still sending it to the client but the client discards it

[crystal crag]

When you are building the DevelopmentClient, are you forced to automatically connect to a server?

I only ask because in my client entry map, the map loads and my UI gets created and put on the screen, then after about 30 seconds, its like the client resets.

Everytime this happens, I see this error pop into the log:
[2021.03.01-01.47.57:896][460]LogNet: Error: UEngine::BroadcastNetworkFailure: FailureType = ConnectionTimeout, ErrorString = UNetConnection::Tick: Connection TIMED OUT. Closing connection.. Elapsed: 20.01, Real: 20.01, Good: 20.01, DriverTime: 20.04, Threshold: 20.00, [UNetConnection] RemoteAddr: 127.0.0.1:7777, Name: IpConnection_2147482037, Driver: PendingNetDriver IpNetDriver_2147482038, IsServer: NO, PC: NULL, Owner: NULL, UniqueId: INVALID, Driver = PendingNetDriver IpNetDriver_2147482038
[2021.03.01-01.47.57:897][460]LogNet: Warning: Network Failure: PendingNetDriver[ConnectionTimeout]: UNetConnection::Tick: Connection TIMED OUT. Closing connection.. Elapsed: 20.01, Real: 20.01, Good: 20.01, DriverTime: 20.04, Threshold: 20.00, [UNetConnection] RemoteAddr: 127.0.0.1:7777, Name: IpConnection_2147482037, Driver: PendingNetDriver IpNetDriver_2147482038, IsServer: NO, PC: NULL, Owner: NULL, UniqueId: INVALID

[dark edge]

@oak hill what's the gameplay feature you're trying to implement with this?

[pallid canyon]

Does anyone know of a reason why a delegate would hang? Sometimes Oculus CreateSession will call success delegate, other times it will not succeed or fail, just hang on a middle step.

Particularly using the Oculus OSS it calls:
OculusSubsystem.AddRequestDelegate( ovr_Matchmaking_CreateAndEnqueueRoom2(TCHAR_TO_ANSI(*Pool), MatchmakingOptions), FOculusMessageOnCompleteDelegate::CreateRaw(this, &FOnlineSessionOculus::OnCreateRoomComplete, Session.SessionName));

but doesn't end up calling the OnCreateRoomComplete delegate. I've run this several times and it has only succeeded once so far as I can see, in the third or fourth try

[tawny talon]

Hi nice people, a quick question about the replicate variables. Say I have a class derived from UObject (Let's say it's called UClass1), and I make it as a variable reference in my HUD widget. When I try to call from my HUD to my player controller's "Run on Server" function which requires a UClass1 argument, would it be successful?

I know that if the parameter is not of type UObject, but of a value type (say int, boolean), it works

seems that passing a reference as parameters on server RPC will cause missing object?

if that is the case, does that mean we'd better keep the data in our player controller owned actors and left HUD focus on communicating with those actors?

[chrome pagoda]

Unfortunately, RestartPlayer doesn't seem to work in my case.

I'd like to notify GameState or GameMode of a player's death and do something depending on what GameMode is loaded. Preferably without relying on DestroyActor to call the event.

[tawny talon]

So you can pass array of value type variables from client to server using RPC, but you can't pass a set/dictionary, right?

by "pass ... using RPC" I mean pass that as an argument

[tranquil beacon]

Hi everyone. I'm very new to creating multiplayer functionality but I'm interested in learning how to incorporate this into my games. Very limited coding background. I want players to be able to connect across the internet (hosting lobbies, finding matches, etc). I know two possible options are Steam Online Subsystem and Epic Online Services--are there any others that would work here? Which would be the easiest to implement with my background?

[twilit stump]

I’m not 100% on this but I think that only applies to TMap and TSet properties, I think you can as arguments.
If not, you can just convert to TArray before calling RPC anyway

[chrome quest]

Hello, people. So I need to confirm something. You can only call RPCs from actors, right?
So, if I mark a function as multicast, server or client in a component class, and I call the same function within the Component class it doesn't treat it as a RPC unless I call the function in an actor class. From a function defined in the actor class.

Please I need clarity on this.

[peak sentinel]

You can call RPCs outside of the actors too, even in the UObjects: https://www.thegames.dev/?p=45 (KaosSpectrum's blog)

[chrome quest]

Thanks. I was of the impression only Actors could call RPCs

[soft shell]

I have a variable that's RepNotify set to "owner only"; the server set's til variable and the owning client (of the actor) calls the RepNotify, but on the listening server the RepNotify is also called - why would it be running the RepNotify, if set to "Owner Only" - should the remote client (i.e. actor owner) not be the only place it's executed?

[chrome quest]

Just read the blog now. Seems I have to add some extra code. Do I have to do the same for actor components also? Not just UObjects

[peak sentinel]

In components you dont need that, that blog post is only for UObjects

[chrome quest]

Oh? That's nice

Thanks again

[peak sentinel]

👌 No problem

[thin stratus]

Mostly because BPs don't actually use OnReps. They check if the variable changed. In cpp you dont have servers calling OnReps at all.

[rich ridge]

Does this mean bp spams the tick function to do this?

[oak hill]

I need an actor that could be a container, a pickup, or something with which every player can interact, but I want it to replicate its content only to the relevant players. So I need two different replication conditions, one for the visual aspect and the other one only for the interacting players. In the end I created an actor component in this actor and wrote a check in ReplicateSubobjects to replicate the data of this component only to the interacting players. @winged badger @signal lance

[winged badger]

ReplicateSubobjects doens't have parameters to distinguish who its replicating to

ActorChannel is the channel of its Actor Owner

[oak hill]

I'm not sure, through ActorChannel from what I've seen I can reach the controller of the players

In fact I'm doing a check based on PlayerController/StoredPlayerControllers inside this actor

[winged badger]

you can reach it with a static function, does't really matter how you get the PC

the check will at best, make it so that the ActorComponent doesn't replicate unless there is at least one player it should replicate to around

then it will replicate to everyone

it doesn't run that function per NetConnection

[oak hill]

But I've seen that ReplicateSubobject gets called once per player if I'm right

Like IsNetRelevantFor

[winged badger]

it doesn't

[oak hill]

So my guess is that there is one ActorChannel per NetConnection

oh

[winged badger]

it gets called when the ActorReplicates

once

and server will map the Actor for replication once, then replicate it to everyone to whom that actor is relevant for

2 approaches here - send the data to everyone and discard it client side if they are not supposed to know it

or - use another ActorChannel just for that data

note that if there is a repeating pattern on who should receive the data

you can run network manager actors that does that extra replication for dozens of other actors

instead of each actor spawning an extra of its own

[oak hill]

But I'm pretty sure it was working... I can see that if I play with two or more clients, the ReplicateSubobject function gets called for every player controller

And I use this to do the relevancy check

[chrome bay]

I'm willing to bet that if the relevancy changes on the players' side, it won't replicate the destruction of the subobject though.

Be an interesting test to try though

What I mean is essentially once it has already replicated to a given connection, it will probably always do that - even if it just gets left with redundant data, since nothing is going to destroy it or clean it up presumably.

[lilac raven]

Hi, my client build that is built through my CI (Jenkins) returns a client outdated error when trying to join the server, its the same build, in our version control, I am thinking I have a file in gitignore causing the issue, where does a build check the build version?

just so i can include that file

[chrome bay]

FNetworkVersion::IsNetworkCompatible

[oak hill]

@chrome bay shouldn't the subobject lifetime be managed by its owning actor?

[chrome bay]

When an actor isn't relevant the server closes the actor channel which destroys it for that client. The sub-object replication method you have currently likely isn't going to handle that for those sub-objects

So if a client changes in a way where that sub-object is no longer "relevant" to them, it's not going to be destroyed - it'll just hang around there with the old data

That's what I'd expect anyway

E.g. say you've made it so that sub-object only replicates to a given team, what happens when the controller changes team?

Unlike an actor, it won't be destroyed most likely - it'll still be there on the client, it just won't get anymore property updates

[lilac raven]

Shall i get NetworkVersion.cpp and ensure all my teams are using the same file in their Engine builds? seems like it pulls an instanced version from the project so it wouldnt make a difference?

[oak hill]

@chrome bay so the relevancy is checked both on server and client if I understood?

[lilac raven]

Yeah, so, its kinda strange, basically my build sever (different pc, same engine version, project gets pulled from git repository before building, same project version) and it builds it via CMD using automation tool. When i use the build from the build sever and open up a dedicated sever I built from my desktop, the build sever build won't connect. My thoughts are that i have a file in our projects gitignore that has the version in it

[chrome bay]

Just Server

But what I mean is, the Server will clean up the actor channel when it's not relevant. It won't do that for sub-objects.

[kindred widget]

Ugh. This discussion reminds me that I need to attempt something similar to Ark's AI system. Only difference is I need to put the XRebirth spin on it and also simulate that data when the actual actor isn't loaded.

[frank birch]

Sorry, A slight confusion on the roles of the gamemode and the gamestate. I understand that gamemode has the rules of this match (for example, "first to 10 kills wins") howeeever... who does the check? the gamemode itself or the gamestate? 🤔
If the gamemode does the check... does it then call a multicast gamestate to let everybody know the game ended? 🤔

[meager spade]

it can do anything to update the GameState

like setting a replicated property (bGameFinished)

or have some kinda state system (which GameMode and GameState has) excluding the Base versions

[winged badger]

@chrome bay @oak hill if the actor that replicates the subobject becomes not relevant it will destroy the Actor, unless it was loaded from package

even if you shove the UObject somewhere else from OnSubobjectCreatedFromReplication, it will still lose the Outer

basically, even if you were to manage to hack your way into a solution

it will be fragile, and that is the last thing you want from your networking code

[chrome bay]

Yeah, I can't see a solution where it works properly tbh

Separate actor is really the only way if you just don't want that data to replicate at all

Or some sort of "info" class that contains data for a bunch of containers like you said

[tawny talon]

Thanks!

Hi nice people today i got very confused by the magic of player controller. I have a custom class derived from actor(of course checked replicate), lets say its called Config. I used my pc to spawn this config class and set the owner of the newly generated object to be the pc, hoping the rpc(client to server) would work. NO. My hud successfully runned, but it didnt fire the run on server evenr from config class.

I tried the same setup for player controller, and magically it works

[kindred widget]

@tawny talon If I understood correctly. You're wondering why when you spawn this actor from HUD, it won't have server rpc capabilities, but when you spawn it from PlayerController, it does?

No. Just reread.

If the server version of your player controller spawns this config actor, then sets itself as the owner of that config actor, then it should replicate to all clients. Then if that one client that is the owner uses their HUD to get that Config actor on their machine after it's replicated to them, they should be able to use it to RPC to server through the Config actor.

So, if you cannot RPC through the config actor, then the most likely scenario is that you're getting the wrong config actor that the particular client does not own.

Not sure how you're getting the correct ref from the hud class, but you could store a replicated pointer in your player controller. Spawn the replicated actor, set it's owner to the player controller, and then set a replicated pointer to the replicated actor. Then you can get the local controller in the HUD class, and use that replicated pointer for the correct Config actor.

[kindred widget]

Whew. Finally getting comfortable with FastArrays and WeakPointers. Finally have both my replicated gatherable foliage and replicated building placement all in place. Both using subclassed foliage and HISM components for better draw calls. At least it's all working great in editor. I need to throw together a quick lobby system and try it out on multiple machines. But now I can actually design stuff again! Need to start working on the building placement system.

[light smelt]

how do you handle multiple levels in multiplayer?

like a modular world with portals between the levels

(a bit like pokemon)

lets say in coop player A is in one level

and player B moves into another level

then player A's computer would have to load the other level and simulate it too

how would i handle that?

[tawny talon]

Thanks!

[lucid vault]

In my game, when a character gets tased, he ragdolls.

Problem is, bones aren't replicated, so if a client tries to shoot someone tased in ragdoll, the collision usually won't match up.

I can use death animations. My problem with death animations is that if you get tased on a stair case, for instance, half of your body will go through the stair case, as animations don't have collision.

Another solution is client authoritative shooting. This is a worst case scenario

Anyone have any ideas?

[chrome bay]

Common approach is to ignore ragdolls for bullet collision

[lucid vault]

I would prefer the players to be kill-able when tased

I was thinking that maybe it would be possible with a death animation + control rig to prevent going through floor, but I'm not experienced enough in control rig to know if that would work

Else, maybe client-side shooting authority for ragdolls

[chrome bay]

Use a physics constraint to ensure the ragdoll stays reasonably close to the capsule on all ends, and accept the clients hit if the hit is within a tolerance distance (when ragdolled)

If you're on dedicated servers then usually you wouldn't run any animation server-side

[chrome quest]

Hello, I created an actor component and discovered that ticking the checkbox for component replicates does not actually replicate the Component. I had to explicitly call SetIsReplicated() in the begin play of the actor component. Just wondering if this is a bug in the Engine or I'm doing something wrong. I googled and found this problem in 4.8 I expected it to have been fixed by now.
Any thoughts on this, please?

Also, do I have to do this for every custom component I make?

[chrome bay]

Not had this issue myself

The actor itself also has to be replicated ofc

[chrome quest]

The owning actor is set to replicate. It's a character infact

The main reason I'm concerned with the Component replicating is that I have some variables in the Component set to replicate but they were not replicating until I did the above.

[eternal canyon]

thats how components work

[dense ocean]

if i call a non replicated event from the gamemode, and it is also defined in the gamemode, is it the same as Run on Server?

[thin stratus]

You seem to be mixing up things

GameMode only exists on the Server. So when you have access to the GameMode to call events on it, then all of it will run on the Server.
Even you access other Objects/Actors from the GameMode, you are most likely still on the Server.
That has nothing to do with a RunOnServer RPC.

[buoyant crag]

hey, I'm trying to save the player's data on the server, and load it every time the player joins it. any ways how to do that? maybe a Database that stores each player's state (for example, a variable for coins).
thanks for the help!

[bitter oriole]

Need a centralized database server, that your dedicated servers connect to, update and download the player's state

[buoyant crag]

any way to actually connect between the server and the database?

[bitter oriole]

The database server can just connect directly like any web server to a mysql db

[buoyant crag]

alright, ill look into it, thanks!

[gritty pelican]

can i replicate variable only for one player? Who interact with object

[open quail]

yes, if you are on bp check the replication conditions on the variable

[gritty pelican]

for example with COND_Custom or COND_OwnerOnly?

on server side i will make SetOwner for Actor

and SetOwner(nullptr) for stop replication, right?

[open quail]

DOREPLIFETIME_CONDITION(AMyCharacter, myVariable, COND_AutonomousOnly);

[kindred widget]

Can someone point me into the direction of why this is warning me about something? I get this log spam ONLY when a player is standing on top of a locally spawned HISM component, which all clients locally spawn.
LogNetPackageMap: Warning: FNetGUIDCache::SupportsObject: BuildingHISMComponent /Game/OWV/Maps/UEDPIE_1_GameMap.GameMap:PersistentLevel.CWorldBuildingManager_0.BuildingHISMComponent_0 NOT Supported.

[chrome bay]

Character Movement can't reconcile it for the movement base most likely

Since it's spawned locally

[kindred widget]

Hm. Do I ignore it, or? Semi annoying to test around the log spam. Would replicating the component holding that HISM instance work?

[chrome bay]

The actual HISM Component itself needs to be replicated from the Server in order to reconcile it properly

That or characters shouldn't be able to walk on it

[kindred widget]

More or less I was attempting a building system. Simple manager replicated and spawned from GameMode. Actor has a fast array. On post replication, it locally determines if the client needs a new component for that static mesh type and spawns it if needed before adding the instance at the desired location. Works fine, except for that problem. I'm not certain how to refactor that if I need to replicate the component. Cause each client would still need to locally add their instances and I wouldn't know if the component was locally replicated when the fast array replicates.

[chrome bay]

Ultimately you need to be able to reference whatever the character is standing on over the network, so locally spawned stuff doesn't really work for that

The alternative would be to spawn it deterministically and trick the network system to treat it as a "map startup" actor

Which @winged badger has done for some procedural generation stuff IIRC

[kindred widget]

Can components hold fast arrays?

[chrome bay]

for sure, anything can

[kindred widget]

I might just move the fast array to the components then. Then the component can do it's own stuff and it would for sure have the component there when the fast array replicates.

[strong vapor]

[Help] anyone know a simple way to replicate what time a sound cue is playing on the server when its replicated

[chrome bay]

Oh another thing you can do, I forgot

Is mark the HISM as "static" or stationary

I seem to recall it doesn't send the base then

[kindred widget]

Hmm. Can try that.

[chrome bay]

But that said, don't think you can make changes to certain properties then

[kindred widget]

Mostly, the instance just needs to be there, or not be there. Past that it doesn't matter for this. If that doesn't work, it won't be that hard to move the array to the component and just rewrite some functions in the manager.

@chrome bay Whew. That one line just saved me a few hours work. 😮 Thanks man.
NewComponent->SetMobility(EComponentMobility::Static);

Probably better for lighting that it's static anyhow.

[chrome bay]

It's a good habit to get into tbh. Landscapes being "Movable" by default is still stupid.

[kindred widget]

Haha. I was doing an AI test a little over a month ago... Had a directional light that doesn't move. Read somewhere on a forum randomly about lighting and characters and such that the lighting's mobility mattered. Changed the directional light to static and with 250 AI, my framerate went up from 45 to about 65. Insane how one setting can kill you.

[peak sentinel]

If I am only going to replicate AI controlled pawns, I dont need to implement prediction, right? Smoothing / interpolation on simulated proxies will be fine?

[kindred widget]

Trying to understand FVector's NetQuantize. If I understood correctly. NetQuantize100 allows two decimal points. So... 4.15274 would be turned into 4.15? And this at the very least would trim off 2 bits. Since each float normally is 32bits, 4bytes*8. But NetQuantize can also lower that number even more than just the extra 2 bits?

[winged badger]

compressing a float makes it lose precision, as you discard the data that held the decimals past the 2nd

but its just a normal vector with overriden NEtSerialize

[kindred widget]

How far can Netquantize100 compress though? If it's like an average of 20-26 bits, that might be worth it, but two bits doesn't feel like it's worth the effort.

[winged badger]

NetQuantize10 is significanly smaller

[kindred widget]

It may very well be enough precision. Just building placement. I can't imagine that I need more than a tenth of a centimetre's precision for that.

[lilac raven]

Hello, is there a way to set my own server / client version for builds? Getting compatibility errors even on the same git repo

[sleek elk]

Somone here uses Advances Sessions Plugin and can explain how to create a Session only friends can find?
The "Create Advanced Session" Node has a option calles "Allow join via presence friends only". I thought this option is what I am looking for, but when set it to true then nobody see the created session. Also not friends.
How do I open a Session (and find it) which only Steam friends can find?

[crystal crag]

@tranquil beacon You're in for a rough journey if you have limited coding experience. Between Epic Online Services and Steam, you are probably best off using steam, since Epic Online Services doesn't have a ready to use plugin for UE4 yet (outside of third party / some init work on dedicated UE4 branch)

@tranquil beacon you are probably better off buying a course on sale on udemy that covers UE4 and multiplayer games

[sleek elk]

I don't get it. I think it can't be so hard to make a session which is only visible to steam friends. Or do I misunderstand "Allow join via presence friends only" and there is not even a possibility from steam and online subsystem to male sessions only friends see?