multiplayer

[dark edge]

So it's like this:
Character:
Button press -> run on server event
run on server event -> select what to do (let's say it's to mine)
Serverside char sets repnotify CurrentActiveResourceNode or CurrentActiveRock or whatever
Onrep -> show the minigame UI for CurrentActiveRock

Minigame:
??? -> Won -> call MyCharacter.MiningSucceeded

Character:
MiningSucceeded -> run on server event MineRock(CurrentActiveRock)
MineRock -> pop the rock

[serene furnace]

I tryed making a few safety still, even Aiming is somehow a bit offset and random so that people needs to aim for real x)

[dark edge]

Basically what the server sees is that it said "yup you're mining this rock", then later the client said "yup i succeeded, pop the rock"

this is 100% cheatable but I'd start here

if you wanted to make cheating not a thing you'd have to have the state of the minigame be serverside too, that'd be spawning an actor representing the minigame and doing networking during minigame play

[serene furnace]

yeah but the "rock mined" is set by the server ^^

[dark edge]

yes

read my pseudocode, the serverside version of the character chose the rock

[serene furnace]

there is no existing ways to prevent cheating anyway x)

[dark edge]

Set it up such that you can just skip the minigame for now and directly call the RPC to pop the rock once CurrentActiveRock onrep fires, later put the minigame in between

[serene furnace]

but yeah what you said is pretty much the only option I could think of if I'm not going for "Actors calls server event" version

[dark edge]

you need to do that

how would hte server know anything then? It wouldn't know the rock is being mined, and it wouldn't know the mining succeeded

[serene furnace]

it was working for just one player, not letting other people mine at the same time x)

basically widget said "Hey we succed to mini game lets call the actor to spawn a rock"

but somehow between one client to another, the ownership of the first client was changed when a second client interacted even tho, both said "owner is the server"

[dark edge]

don't bring ownership into this

[serene furnace]

yeah thats making things way too messy at the end of the day lol

[dark edge]

your interface with the game world is your pawn, use it. It'd be best to make it way more general but for now make RunOnServer events like:

WantToMineTheClosestRock
and
OKIMinedThisRockNowPopIt

that's what the server sees

[serene furnace]

yeah i'm going for that RN and remaking it into pawn

[dark edge]

you could just as easily do it like:
WantToMineThisSpecificRock
or
WantToInteractWithSomething (the most general and what you'd eventually end up with)

[serene furnace]

I already have a "im interacting with what ever item is close to me" function, yeah

it's not on a beginning point of dev ^^

I'm on it for a couple years now lol

[dark edge]

yup, so interacting with a rock, the rock tells InteractingPawn "hey, I'm a rock, set RockImTryingToMine to me"

the onrep fires, the widget shows up

later, if you succeed, the widget tells the char to tell serverside char "yup I mined RockImTryingToMine, pop it now"

If you wanted it to be cheat resistant you'd do it like:
"hey InteractingCharacter, here's a MinigameActor I just spawned for you to deal with"

[serene furnace]

well thats what I'm doing, the server fires a Client side event to open the widget

[dark edge]

that MinigameActor could have its ownership set to the player so it can directly RPC through it

[dark edge]

I'd use RepNotify

[serene furnace]

why would you notify all players that this pawn opended a widget ?

[dark edge]

you can make the replication condition owner only

but it's just better to have events that respond to state be driven by repnotify

the state is "I'm interacting with this rock"

[serene furnace]

why is it "better"

I mean rep notify only fires when the condition changes, then it means I would have one more function per minigame instead of one big Event graph with all minigames

[dark edge]

OnRep_CurrentRock -> if CurrentRock.IsValid -> true -> show CurrentRock.MinigameWidget
-> false -> hide any MinigameWidgets

Now if CurrentRock gets set to null like when the char gets killed, or walks away, or the rock gets mined, it'll Just Work™️

[serene furnace]

thats what I'm doing with owning client tho ?

if you get out of collision sphere of the rock, the menu closes

and you can only interacting if you are overlapping with the sphere

[dark edge]

I mean you do you but RepNotify is the most robust way to do something like this. That way your code can just be like a state machine.

[serene furnace]

well since the widget is closing if you leave the collision sphere of the item, and the item is not movable in anyway, and handled only by server

I guess it's overall even more protected than I thought lol

and then the only way to get a ref to the proper rock to mine is to directly interact with it withing this sphere x)
Packet injection will probably be the worst for my project

People triggering event like "hey I minned properly" from outside 🥲

even packet encoding wont save you, they would just inject encoded packets until they find the right one lol

[serene furnace]

well yeah I was stupid, using the " get owned player pawn" from the widget gives a super fast way to get the pawn and something that can call server event.

And then from the interact event set a variable "item im interacting with" on the server gives me a safe way to get "what ever item i'm currently interacting with"
to keep track on "who is mining what"

And from there trigger a server event that spawn item on mining sucessfull and set transform to make everyone see that the rock goes smaller and smaller

I guess it was a good way to see how the engine is handling the ability to call a server event and such

[rough dock]

should a match timer be in the gamemode then replicated to the game state or should it just already be in the gamestate

having trouble with match flow since it can only be set in the gamemode and stuff

[peak mirage]

Could you please elaborate this a little more? Official document does say how to enable Iris, but not tell how to use them, for example, how to tell the system a property is marked dirty.

[obtuse field]

In FSocket if I want to send the data, I put all the data in one Send function, and it will chunk it for me, right?

[sinful tree]

It probably should be in the gamestate. I'd build a pairing "timed" game mode to a "timed" game state where you wouldn't want to use one without the other, but the game mode can react to what the timer in the gamestate is doing, or control the timer from the game mode.

[fallen sparrow]

Hey guys, Client crashes with a fatal error on execution of servertravel.

Any Ideas?

It works in editor but in packaged builds it crashes. UE 5.2.1 blueprint project with Advanced Sessions and Steam sessions.

[plush shoal]

@thin stratus I have gotten logs

Server

Client

[obtuse field]

Do you have debug files included into the package?

And package it as DebugGame

[obtuse field]

Anyway, it seems like something with chaos physics is causing the crash

[fallen sparrow]

Thanks for the response man, I've never debugged a packaged product before so this'll be new

[obtuse field]

Do you have some print string that shows where you try to connect?

[plush shoal]

I'll check the logs to see where it tries to connect

I don't have a print string but I'll be able to tell anyway

It appears to be line 1972 on the client @obtuse field

You see it loop back to the default level because of the playfab request

[2024.03.18-01.50.31:319][ 42]LogSteamSocketsAPI: Verbose: SteamSockets API: Log [#1335973175 P2P SDR steamid:76561198357159093 vport 7777] closed by peer (5010): Relay received unexpected noconnection packet

seems to be the failure

Seems to be on Steams end

It appears that maybe there's some misconfigurations in my .ini file

(Based on a community fourm I found describing the error code even though its in a different context)

This might potentially be the issue

it seems there was a duplicate line along with extra netcode at the top

I'll let you know if the clean up of engine.ini fixed it

[obtuse field]

How can I get connected cliens from FSocket server?

[obtuse field]

I see that there is a function HasPendingConnection, but it doesn't return the meaningful data about the connection

[gloomy tiger]

Nested FFastArraySerializer won't trigger their PostReplicatedAdd by design, right?

[chrome bay]

You can't nest FFastArraySerializer at all. It'll replicate like a regular property

Only object-level UPROPERTY's can use delta serialization

[gloomy tiger]

I mean, I can nest - only it won't behave as a FFastArraySerializer - right?

But yeah, that makes sense. Thank you.

[static lava]

During movement with prediction where you do: Server Tells you you have been slowed(or rootmostionsource movement like knockback is applied) to the client-> client applies slow effect(prediction)->calls back server to know it started prediction and server can also apply

How do you make sure it cannot be cheated? Like say server sends you a slow effect

And you don't call server back, should there be a failsafe timer that slows you on server anyways after a given time like 500-600ms?

Is there a more elegant solution or this should do it?

As cheating on private servers is still an issue even in non hardcore games that still have competitive elements like Survival games

[chrome bay]

Yeah exactly, it'll just be treated like a "regular" property

[mental pendant]

If I call a Server RPC on the Pawn from my AnimInstance, is that going to be called multiple times for each client replicating the pawn?

[gloomy tiger]

I currently have this design:

struct FMyTrait {
  UPROPERTY()
  FGameplayTag Id;

  UPROPERTY()
  float Value;
}

struct FMyEntity {
  UPROPERTY()  
  FGuid Id;

  UPROPERTY()
  TArray<FMyTrait> Traits;
}

class UMyActorComponent : UActorComponent {
  UPROPERTY(Replicated)
  TArray<FMyEntity> Entities;
}

To summarize the problem with this design: whenever I change a single FMyTrait of FMyEntity, all the other traits would be replicated as well, whereas I'd like just the changed one to go over the network.

That said, do you have any suggestions on how to improve this design so it is more network-efficient?

Or rather, I just came to the realisation I don't know the following for a fact - are TArray<...>s delta-serialized by default? In the sense - if I add something into a replicated TArray<...>, will that single value be transmitted over the network or its default is atomic?

[gloomy tiger]

It's going to be called as many times as you call it, and for each and every player to whom this Pawn is relevant for.

[mental pendant]

the true question should be: is the anim instance running separately on every client? I guess so tho, so I'm just gonna put delegates in there and only bind them in the locally controlled pawn

[gloomy tiger]

That's probably the best approach, yes. However, do you really need an RPC? A replicated property wouldn't get the job done?

[mental pendant]

I think with structs you have no choice because you are basically copying their value over the network? For fine-replication maybe actors are necessary

[gloomy tiger]

The design is irrelevant now, actually. I just need to confirm for a fact whether a (nested) TArray is delta-serialized or atomic.

[mental pendant]

I have an orchestration of "trigger animation -> receive anim notify -> trigger another animation" that I use for abilities such as firing, reloading that have some kind of "state" internal to them, so I need to wait for animations to finish and then call the relevant functions on the server to continue the ability

[gloomy tiger]

From my experience (shipped 2 multiplayer games), I feel that's not ideal. You can orchestrate the same in a more reliable and less-expensive (RPCs have a higher overhead than replicated UPROPERTY()s) way via replicated properties.

Oh, wait

Nah, ignore me. *Server* RPC.

[mental pendant]

I want the client to decide when to trigger the next step (because that's smoother for the player) but still let the server call, and multicast, the function. Like, inserting a new mag after the animation for ejecting it has finished, this is something I wanna trigger from the client (so the animation is smooth) but then it's the server telling everyone to insert a new mag

[gloomy tiger]

🤔

But I feel you don't need that RPC neither, because the server knows when the animation has started and it also knows when it has finished (not sure about Dedicated Servers, though.)

I mean - these are not questions you are asking, am just spitting out randomly

[mental pendant]

yeah that's where my doubt started, I don't get how AnimInstance works with replication.. like, if the server gets an AnimNotify, is the client in control of the pawn receiving it at the same time? Since it's a UObject is not replicated afaik

hence why I am using a Server RPC 👀 I want the controlling client to trigger the new animation when it sees the old one finishing

[gloomy tiger]

Cosmetics don't usually replicate - that includes, but is not limited to, animations (and AnimInstances)

I believe the only RPC you want is StartReloading(), for example

Because the rest is fairly predictable

If you're listen server, then the server knows which animation is running, hence the AnimNotify will trigger there as well

[mental pendant]

ideally yes, I am probably mixing up state changes with cosmetics at intermediate steps of the ability

[gloomy tiger]

Are you going with listen server or dedicated?

[mental pendant]

listen

[gloomy tiger]

So yea, probably the single RPC you need for this entire pipeline is a StartReloading

You start the animation locally
And you start the animation remotely

The server, which is also a client, sees the animation, hence the AnimNotify is available to it. So the server naturally knows when the magazine has to be filled up.

[mental pendant]

I see, I was just thinking in case of lag this would cause weirdness on the client-side, but that's the client's fault I mean 👀

thank you this really helps!

[gloomy tiger]

Now, just to bump my early question a little...

[solar stirrup]

It'll send the entire array

afaik only the fast array serializer supports delta replication, array wise

[obtuse field]

Is there a way to know if TCP server accepted connection on the client, without sending additional TCP call?

[vagrant grail]

Do we agree that saving players joigning the game in an array and get the 0th element will always return the host of the game in a listen server context ?

[gloomy tiger]

I'm not really sure this is entirely true

I may be mistaken, but it seems this is only true for remove operations? 🤔

[lament flax]

i got a replicated actor

from the server i want to call an event on the client

the server fires the event, but for some reasons it get executed on server (instead of client)
its not a debug bug since it only prints "Server :..." in the output log

any ideas ?

first time i got this bug

looks like this is the source of it

[warm lintel]

1. Your object might not be owned by any client
2. Your server (if listen server) might actually be the client
   It's not a bug, it's intended behavior

[lament flax]

• all clients in the level owns it
• i dont have any listen server, all players are clients

on the breakpoint hit :

(i have only 1 client rn)

when doing multicast it is called on server and client

[warm lintel]

They can't all own it, only 1 owner per actor

far as I know at least

[chrome bay]

correcto

Can't call a Server RPC on something you're not the "Net Owner" of. And only one player at a time can be a Net Owner of an actor

[lament flax]

oh

so i am forced to use multicast and filter with a authority switch ?

[chrome bay]

You can't call a multicast from a client

If many clients can interact with one actor at a time, you need to route the call via something you are the net owner of. This is a common thing for interaction systems for example, where you might put a component on your pawn or controller, with an RPC that takes a "target" actor parameter.

[lament flax]

i am on server side

the issue is to get to client side

[fathom aspen]

err, it's also true for regular TArrays @gloomy tiger

[lament flax]

ig i'll add a reroute to the player character

[chrome bay]

You're calling a Client RPC on the Server? Should be fine then - but only the Client who is the net owner of the actor will receive it

[solar stirrup]

i stand corrected

[chrome bay]

If there is no net owner, it'll run on the Server itself

[lament flax]

well rn, on the server side i am calling an event "on owning client", and my client doesnt receive anything because it is called on the server (because he is the owner ig)

[chrome bay]

What type are you calling the RPC on?

[lament flax]

actor

already placed in level before start

[chrome bay]

Ah, right yeah, so it has no net owner then

It belongs to the level, so no player owns it

[lament flax]

ill change the logic

the player character is owned by the client right ?

[chrome bay]

it is

This sounds like bad design already though

[lament flax]

okay, ill call a event from server on it to make it switch to client

[chrome bay]

If the actor is in the level, surely it's relevant to all clients?

[lament flax]

what alternative do i have ?

[lament flax]

wdym by that

[chrome bay]

The actor pre-exists in the level, so surely every player can see it and/or whatever changes are made to it are relevant for everyone?

[lament flax]

the goal of executing this event to server side is to call a interface event on the HUD

the HUD is null when the server has the player controller ref (which is normal)

rn the 2 possible fixes i have in mind is :

• calling a multicast on this actor, filter to get the "owning" client, then switch to client to call the event on the HUD
• calling from server a event on the player character, then switch to client to call the event on the HUD

[rich crag]

can someone tell me why, when i cast to a child bp and it's replicated, i end up with two copies? As a standalone blueprint, it doesn't have the issue, but part of another blueprint, it does.

I had this problem with ladders on my ship and now having the same with doors in houses

[queen escarp]

if im sending positive value then it works but if i send a negative value it dosent work ??

[frail barn]

i need to create a team-based range-restricted visibility system
pawns of a same team is visible to each other, but invisible to another team pawns outside of a vision's range
i have 4 arrays for this, "all pawns in a team" for both teams, and "foes in a visibility range" for both teams
to make it work, all pawns is set to hidden in game, and some pawns need to be set visible by some criteria
so, the main question is:
how to say at the server side to every client separately - "unhide for yourself pawns from this array"?

[hardy turtle]

hi guys! is there anybody who can help me solve a little issue i have?
I know i can start a lobby by opening a level with the option listen

is there any way i can change that option on the current gamemode? what i would like to achieve would be having a main menu that turns into a listen server to have friends connect to it (as it became the actual lobby) and then start a game

Thank you!

[queen escarp]

i dont get it wtf is goinmg on 😮

[obtuse field]

I have such code, and for some reason, client is not receiving the data from the stream. Bytes Read is equeal to 0

if(IsRunningDedicatedServer())
{
TArray<uint8> Bytes;
        FMemoryWriter MemoryWriter(Bytes);

        TMap<int32, FInstanceBuildingData> PlacedInstances;

        TArray<int32> TestArr;
        TestArr.Add(14);
        TestArr.Add(15);
        TestArr.Add(16);
            
        MemoryWriter << TestArr;

        int32 BytesSend;

        UKismetSystemLibrary::PrintString(GetWorld(), "IS IT SENT??? " + FString::FromInt(Bytes.Num()) + " " + FString::FromInt(MemoryWriter.TotalSize()));
            
        TCPChunkDistributor->Send(Bytes.GetData(), MemoryWriter.TotalSize(), BytesSend);
        
        //TCPChunkDistributor->Recv(Data, BufferSize, BytesRead);
    }
    else
    {
        uint8 Data[4096];
        int32 BytesRead;
        
        ESocketConnectionState SocketConnectionState = TCPChunkDistributor->GetConnectionState();

        if(SocketConnectionState == SCS_Connected)
        {
            UKismetSystemLibrary::PrintString(GetWorld(), "CONNECTED");


            TCPChunkDistributor->Recv(Data, 4096, BytesRead);
        }
        else if(SocketConnectionState == SCS_NotConnected)
        {
            UKismetSystemLibrary::PrintString(GetWorld(), "NOT CONNECTED");
        }
        else if(SocketConnectionState == SCS_ConnectionError)
        {
            UKismetSystemLibrary::PrintString(GetWorld(), "CONNECTION ERROR");
        }

        UKismetSystemLibrary::PrintString(GetWorld(), "READ DATA: " + FString::FromInt(BytesRead));
    }

It says that it is connected btw

[eternal canyon]

https://github.com/87andrewh/CornerCulling

[obtuse field]

How can I debug this?

[eternal canyon]

because its negative

[queen escarp]

@eternal canyon wdym ?

[snow trail]

you cant have a negative walk speed

[queen escarp]

No i mean

Sec ill show u

[dark edge]

Explain what you're trying to do

the specific game mechanic

[lament flax]

when the server call the Use event i want a widget to show (the inventory of the chest)

[dark edge]

uh

You want to be able to walk up to a chest, press a button, and see the inventory right?

[lament flax]

yeah thats what i have working rn

[dark edge]

ok so what's the problem?

[lament flax]

the problem was that the actor is own by the server so the owning client was the server itself and not the player interacting with it

[dark edge]

thats fine

do the interaction rpc through something the player owns, usually the pawn

Pawn:
Input -> run on server event
run on server event -> figure out what to try interact with -> call Interact on it

done

[queen escarp]

@eternal canyon @snow trail they are both coming from the same event same conditions the + works and adds fine but the - dose nothing

[lament flax]

what ive done is that the server gets the actor and call the event inside

[dark edge]

the server what

just saying the server doesn't help

the serverside version of what actor?

[lament flax]

the chest

[lament flax]

left : chest
right : player

[dark edge]

Just looking in inventories can be completely local, no need to have networking involved at all assuming the inventories are replicated

[lament flax]

btw can this step be passed ? does the server owning the chest knowns who owns the player as client ?

[dark edge]

no

none of that

[lament flax]

i need the serve rto do it, inventory data are server side

a player lagging could duplicate stuff

[dark edge]

ok first off, do you want to replicate your inventories or not?

[lament flax]

they are

[lament flax]

tested and it can be skipped

[queen escarp]

adriel

any ideas in my case ?

[magic vessel]

Small question here, I'm trying to work on prevent cheating (such as packet sniffing) but I have no experience with this. What tools do hackers usually use to cheat that I can use to verify my tactics are working (or at least so I can tell my community that there have been efforts undertaken to limit cheating)

[obtuse field]

Use FTcpListener

[fallen sparrow]

Hey Hive, I got the debug going and I caught the exception

Client Crash on ServerTravel

So I guess I'm wondering what's next, I never mess with the code or engine level stuff. I've messed with C++ in the past so I'm at least familiar with some of the syntax.

[dark edge]

Why are you letting the client say what speed they should have?

What is the game mechanic you're trying to do?

[frail barn]

thank you, but its overkill to me
i need simpler solution
just right way to set events on server/ on client

[queen escarp]

@dark edge well this is a char component thats why in using owning, its basicly a slow system

But i got it working kinda

[dark edge]

the client gets to say what its max speed is

trivially cheatable, I can just set it to be 10,000 and zoom everywhere

[dark edge]

Do all of this on the server only

[queen escarp]

How would u change the speed from the local files u mean or?

[dark edge]

the server should say what speed you have

not a client

what changes the speed?

a debuff?

[quaint frost]

hi everyone! does anyone use replay system in case of showing epic moments directly in session? i see how it works and don’t see easy solution, so maybe someone have experience with this?

[queen escarp]

Yeah upon start the server dose set the speed

Yeah a debuff

[dark edge]

just do it all serverside

[thin stratus]

#multiplayer message

I linked this once

But I never implemented any of that

[quaint frost]

thank you! this is what I’m looking for, start point!

[lament flax]

if i code my game to have all players being clients, and my server to be a dedicated
but later on change, and have 1 player host (listen server (client & server)) and the other players being clients

would this mean i will have to redev some stuff ? or should i be fine ?

[solar stirrup]

Depends on how you handled your code

There's some pitfalls when a client is also the server

Better to handle it right off the bat if possible

[lament flax]

so its not possible (or very hard) to dev to make both working ?

[solar stirrup]

Not impossible, not hard at all

[lament flax]

what should be different then

[solar stirrup]

Just some edge cases you have to keep in mind

[rich crag]

Can someone please explain this???!! Conditions: have a replicated door (or interactable) that is a child blueprint of another blueprint. Cast to that child blueprint. Be in a map using world partition. - Under these conditions, I get a duplicate child that exists only on the (each) client. In the case of a door, a door opens, yet another door is there, but does not stop you from walking through (which is what tells me that it's on the client - you can walk through it because the server says it's open). Under any other conditions - the blueprint is standalone in an open world, the blueprint is a child of another blueprint but in non partitioned world, or you do not cast to the child blueprint, there is no duplicate. This is most unfortunate because I'm having problems getting non cast methods to properly replicate.

[short arrow]

I know this was hours ago, but we actually saved lots of processing time by making the inventories not be replicated, so we did actually use RPC's to check inventory information, not sure if you've ever tried that before

but you should consider it if you haven't before

[solar stirrup]

• Rep notifies don't execute on the server (if you're using C++). Meaning a client that's also the server won't execute them automatically. You have to call them manually if you want them to run on the server.
• Your server is also a client, so you want to be careful not to run cosmetics from other clients on the server as well.
• Any code that you want to run when you don't have authority (for clients only) won't run on the listen server host (since they always have authority). Another thing you gotta be wary of (stuff like Switch Has Authority in blueprints, or HasAuthority() in C++). This is generally solved by checking if a pawn is locally controlled or an actor is locally owned instead of checking for authority.

Probably plenty more I can't think of right now

[lament flax]

ty for sharing, i'll see if it get costy
all inv are less than 3/4 slots, so i will probably be fine :)

[lament flax]

thanks for sharing

[solar stirrup]

Shouldn't be costly at all

As always, profile before optimizing for no reason

[lament flax]

i've been doing as many authority/controlled pawn check as possible, so if i change the net mode, i'll probably have to redo stuff, but not most of it

and im in BP so rep notifies doesn't change behavior

also, im curious why doing "set members" in struct or changing arrays with "add","remove","clear" doesnt trigger repnotifies

i have to do stupid stuff like this to trigger it

[solar stirrup]

Blueprint rep notifies are a bit annoying since they get called in the setter of the variable or when it gets replicated

Any other modification won't call the rep notify

I'd recommend calling your rep notify function manually instead of setting

@lament flax

[lament flax]

how can i call them in BP ?

[solar stirrup]

Isn't it in the function list?

Not sure if you can call it manually actually, but try

If you can't, just have your rep notify function call another function that does the processing you want

[lament flax]

not callable

i think i already tried

[solar stirrup]

^ this then

That way when you want to call it manually, you just call the function the notify calls

Cleaner imo

[lament flax]

yeah i did this trick, using a useless bool var

somewhere elses

[lament flax]

more info on why

[rich crag]

I have also figured out that it does not duplicate if i turn off spatially loaded.

on the parent. It does not matter if the child is spatially loaded.

[indigo brook]

If you guys were to relearn how to make a multiplayer game, what advice would you give yourself?

[fallen sparrow]

do it from the start in C++

[indigo brook]

That's fair, there's more things to control with there for sure

[fallen sparrow]

Its not so much about the control, its that there are quite a few engine hickups that without it you are just SOL

[indigo brook]

I'm on my multiplayer learning journey and I gotta say, I think I'm asking the wrong quesions to myself when creating. I don't fully understand the rules and I'm feeling a bit lost haha.

[mental pendant]

What is the proper way to check if a Pawn is on the server? I am running an HasAuthority() check inside my pawn's BeginPlay() where I do some initialization, but it's getting called on both client and server. I only want to do this initialization on the server

[fallen sparrow]

Like my issue currently lol. ServerTravel causes a fatal error on the client side related to a null pointer somewhere in the Chaos physics. So I'm starting my journey of fiddleing for better or worse to get it to work.

[indigo brook]

That's great news!

I'm trying to f*** around with skeletal mesh cosmetics changing but I can't seem to grasp the replication side of things. I get close, but it feels dirty

[fallen sparrow]

Probably a cusome event with server and reliable

[fallen sparrow]

Yeah, sometimes the idea of holding client and server ideas in your head while also factoring in the server is also a client gets me a lot

[indigo brook]

Aye, truer words were never spoken!

Server is the god, and everything has to pass by the server, but my issue is when you are the client trying to get info from your own PC or the clients Game Instance to the other players

[fallen sparrow]

What kind of data are you wanting to go where

[mental pendant]

"the server is also a client"
I need this on my wall

[indigo brook]

If it's a listen server then on the wall it goes!

[mental pendant]

on the widget

[indigo brook]

Example, I spawn a third person character into the lobby map. I have 1-5 players. Each player that spawns in has to also pass along their cosmetic (head, torso, legs) struct. Then that has to basically show the right parts on their custom character. It's something that's been done for over a decade in multiplayer games but I can't figure it out haha

[fallen sparrow]

A guess a hypothetical Chriss, if you want to have other clients see your players new skeletal mesh, you'll have to Server RPC the mesh change on the client and then multi that client change to all the others

ClientChangeMesh->ServerChangeMesh->Multi everyone change mesh

[solar stirrup]

You don't want to use a multicast RPC for this but a replicated property

Since this is a stateful change

[indigo brook]

@solar stirrup I've been using repnotify for that for sure

I seem to get things to work okay, but it's like wack a mole, I fix one issue and another pops up. Example, my character can change items fine on server, but then the client, when changing items via widget and struct, it crumples the body parts at root location haha

[fallen sparrow]

scaling issue?

[indigo brook]

Naw, it's a body part issue. So in the struct, I SetMembers of the head, or Set Member of torso. However, on the client, it zeros out all the other struct slots, thus, no Mesh (body) and the parts just go to root. However, the struct works fine, same system on server. It's the weirdest thing

Wack a mole all day

Or character clothes spawn fine in the lobby but not the game. Or vice versa, clothes don't spawn in lobby but do in game haha

[fallen sparrow]

I know that replicating structs introduces some problems lol

[indigo brook]

Right?!

[fallen sparrow]

Ive never been able to pass a struct directly in replication but passing replicated varriables into a struct works just fine

In my project items are structs. When the player encounters a pickup, the pickup calls the server to set the varriables in the object struct and deletes itself, if I try passing a struct to struct nothing is set

[indigo brook]

Yeah, the struct only houses skel mesh slots, originally it was integers but you'd think it wouldn't be an issue

[fallen sparrow]

Passing skeletal mesh assets as a struct could be an issue I feel like, have you thought about instead of passing a mesh, passing an integer for a switch that predetermines skeletal mesh assets on the client?

[indigo brook]

Yeah, I could do that. Are you sure structs have these kind of issues with multiplayer usually? If you way it does I might try that technique

[fallen sparrow]

Well my struct does have a skeletal mesh so im not sure

I'll post a picture

[solar stirrup]

What problems?

Sounds like you're doing something wrong

[indigo brook]

This is what I have for my structs, the S_CharCustomization is just skel mesh slots

I'm experimenting, so this dosn't work right now (which is expected)

[solar stirrup]

What's the type of Body Parts/Head Parts etc

(also why not replicate the entire struct instead of each member individually?)

[indigo brook]

I messed around with replicating the struct too. Again, I've been playing try this, try that game today haha. It's one of those things were you try 1000 things, forget which works in one build but not the other

Hence why I feel lost, I don't fully understand the rules, but I'm throwing speghetti at the wall to see what sticks hah

[solar stirrup]

[indigo brook]

Skel meshes

[fallen sparrow]

well im a faily acomplished spaghetti thrower lol

[solar stirrup]

Those should work

[indigo brook]

Right! haha

[solar stirrup]

Assuming they're assets on the disk

[indigo brook]

Indeed they are

[solar stirrup]

What's the issue

[indigo brook]

The main issue is that I need to learn how to do network communication. I understand the basics, but there's some techniques I don't know how to accomplish

[fallen sparrow]

Here's how I do my weapon struct

[indigo brook]

Like how do I pass a clients game instance info to the server and the server then distrubutes that info to the other clients (their custom characters look like what the clients set up)

[solar stirrup]

Game instances are not replicated

[indigo brook]

I know this, but that info, can't it be still passed on though?

[fallen sparrow]

The GameMode is persistent on the server

[solar stirrup]

If you mean you saved the player's character customization info in the GameInstance, you can just then call a Server RPC on an actor the player owns (PlayerController, PlayerState, Pawn if currently possessed)

Don't use the gamemode for this, not really the place for that

[solar stirrup]

This looks okay however, you would only want to call the Server RPC on the client (so the client sends the server their desired character look after loading it)

[indigo brook]

Agreed, that's the part I'm confused about, taking that info from the client and passing it to the host

[solar stirrup]

For simplicity's sake since you're beginning, I would recommend doing this on the PlayerController

Each client only has access to their own, the server has access to them all

[indigo brook]

Looks good. I thought using Make for the struct instead of SetMembers was a bad thing?

[fallen sparrow]

PCs are persistent as well

[solar stirrup]

I wouldn't replicate so much info

Your weapon definitions should be in something like a Data Asset or Data Table

[indigo brook]

@solar stirrup Aye, I spawn the player in the PC

[solar stirrup]

A lot of the info you're replicating doesn't need to be replicated, it's static info that should be loaded from a data asset or something

[indigo brook]

I wish I could take better pics of the graphs

[fallen sparrow]

That's true, an optimization effort for the future for sure

[solar stirrup]

In the Player Controller's Begin Play, check if it's the local player controller, if so, call the Server RPC

[solar stirrup]

Not even just an optimization, this warrants a refactor sometime soon if you wish to expand on weapons and all

[fallen sparrow]

Well I'm currently hard stopped at the client fatal erroring and exception to do with the Chaos phisics during a servertravel call, so I doubt if I'll ever get to that point

[indigo brook]

Alrighty guys thanks for answering, I wish I had more energy to continue haha I was working on this all day and am burnt out for now. I appreciate the assistance guys, you rock

[solar stirrup]

good luck to both of you

[fallen sparrow]

Yeah np man, hope you get it figured out

[indigo brook]

@solar stirrup I don't want to be that guy, but you seem to have a good solid grip of networking system, would you be able to (not all the time) review and correct my work? Aka, can I friend you?

I'm looking for Networking Sensi's

[solar stirrup]

Sure, I'll answer whenever I have time ^^

[indigo brook]

I'll be sure not to spam, just need some correcting.

Thanks @fallen sparrow for answering as well, I hope you get your Chaos physics server travel issue fixed too!

[frigid elk]

What is a really good resource for me to learn how to stop my client from rubber banding like crazy

smoothsync does not work for me so far btw so i could be destorying the connection another way

[reef bison]

I am seeing a very odd behavior with my inventory. when an item is added to the inventory I do a broadcast to the UI so it can be updated, this works when playing as a listening server but if I have 1 client and 1 listening server, whenever the client pick ups an item the server also gets one (in the UI) because the broadcast is also running there

I narrowed down the issue to a broadcast call that I added because of the server but I have no idea how to only run this code if the inventory is from the server. I thought it would just be a matter of doing a check for authority on GetOwnerRole but for some its always returning the component from the server?

my steps to recreate the issue:

1. I open two games: client and listen server and their inventories. both are listening for the broadcast so the UI can be updated
2. the client picks up an item. this is triggered by the OverlapBegin function in the drop actor, all the code onwards is running on the server (because of if (!HasAuthority()) return)
3. I get the actor that collided with the drop, then the controller and then the inventory manager component
4. I call the function to add the item to the inventory. this all bubbles down through some stuff until it hits the broadcast where I am trying to do the check. this is the code I have:

if (OwnerComponent && OwnerComponent->GetOwnerRole() == ROLE_Authority)
{
    UE_LOG(LogTemp, Warning, TEXT("Owner: %s"), *OwnerComponent.GetFullName());
    BroadcastAddedMessage(NewEntry);    
}

5. even through all of this happened from the inventory component of the client player, the OwnerComponent is pointing to the server's inventory component. why?

ok maybe my question is too big I added some logs in the drop actor and I seeing the weird behavior so I will simplify it:

void ATerraWorldItemDrop::OverlapBegin(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
    UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
{
    if (!HasAuthority() || bHasBeenCollected) return;

    // Server-side code
    const ATerraCharacter* Character = Cast<ATerraCharacter>(OtherActor);
    if (!Character) return;

    UE_LOG(LogTemp, Warning, TEXT("Character controller: %s"), *Character->Controller.GetFullName());
}

why is the controller always from the server if the character that collided with the drop is from the client?

[fossil spoke]

HasAuthority() && IsLocallyControlled() == Listen Server host controller.
HasAuthority() && !IsLocallyControlled() == Server side but looking at a Client owned controller.

The Server always has authority over all Actors, so its not a sufficient check on its own in this case.

[reef bison]

thanks, this check is very helpful

I just noticed that I understood the logs wrong. what I was logging was the actor component from the client but instanced on the server, which makes sense

I just need to find a way to get a reference to the pawn to try this now

[hoary spear]

Cond_OwnerOnly?

[reef bison]

the IsLocallyControlled check worked, thanks!

[reef bison]

I haven't seen this one yet, I am reading the doc page about it

I am not sure if that would help because the code to add an item in the inventory always runs in the server

[fossil spoke]

You are correct, that wont work. The issue is unrelated to the property replication condition.

[reef bison]

in the subject of replication, I know that unreal networking model is authoritative but is there a way to invert this for a few properties? e.g. the items in the inventory have a position and I dont want the user to notice the delay when reorganizing the items, is it possible to let the client "own" the inventory authority and replicate it back to the server?

[fossil spoke]

When the Client sends information to the Server that it had moved an Item, it can tell the Server to trust the Client that it did move where it was told. Sure.

But what you probably want to do, is have the Client "predict" (perform the move operation locally) that the Server will tell them they did a valid move. If they didnt do a valid move, the Server would tell the Client and the Client would effectively rollback that move so that it remains in sync with the Server.

[reef bison]

I thought about doing that but it sounds like a lot of work to implement it 😅

[fossil spoke]

It is.

Welcome to having to deal with Latency.

[reef bison]

for the record the game I am developing is similar to terraria so I am prioritizing a better experience for players with high ping than having it being anti-cheat

[reef bison]

is there something built-in for that (similar to the Replicated flag in UPROPERTY) or do I need to change the inventory to being non replicated and create a RPC to update the inventory in the server after a change?

btw thanks for the GenericItemization repo, I was peeking at the sample the other day to figure out how to build a part of my UI

[fossil spoke]

The UI is bare minimum to just demonstrate the Plugin, so it doesnt do anything fancy like Client side prediction of Item moves.

[fossil spoke]

I dont know exactly how you have it setup so cant really recommend how you need to adjust what you have.

But the general idea is that you get the Client to run the same code that the Server would run, but allow the Server to still be authoritative over the final result.

It can get complicated.

[hoary spear]

It does if the broadcast is called from the onrep of the inventory

Which for me feels like a natural place to call it

[reef bison]

ah I meant if I wanted to do the other way around: the inventory logic is all handled on the client and it updates the variable in the server automatically, I currently have UPROPERTY(Replicated) FTerraInventoryList InventoryList; in the component and was thinking about something like UPROPERTY(ReplicatedFromClient)

but I understand this is a long shot since unreal is all about authoritative networking, I might need to implement this myself

[hoary spear]

Question is can you trust the client to that degree?

[reef bison]

either way I appreciate the help so far, I will continue with the server inventory and think about changing it later on if the delay is too annoying

[reef bison]

yeah I don't mind cheaters, the game is like terraria so the vast majority of the time you will be playing with friends

it would be awesome if I could do everything on the server but it's a trade-off for high latency players

[hoary spear]

I run it all on the servrr and cant say the delay have bothered me that much. How often is a player starring at their inventory while picking something up

Feels like a partially self-constructed problem

I do async loading aswell so im bound to have delays 😅

[fossil spoke]

A meta like that does not exist.

[reef bison]

well yeah you are right, I have no data to backup the claim that the game would be annoying with a server authoritative inventory because it's still very early on 😅

I will keep an eye on it but its good to know that you dont have issues with it

[fossil spoke]

You can still have server authority. You just have to predict the moves correctly.

[reef bison]

do you happen to have any resource explaining how to do that with unreal so I can study it more?

I think predicting the moves of the inventory isn't hard, what I have no idea how to do is the client/server version of the property because it needs to be changed by the client and then corrected by the server

[fossil spoke]

Unfortunately there isnt really a resource for it because it typically requires a feature specific implementation.

Just google client side prediction and see what you find

[hoary spear]

Prediction is definetly an option ofcourse^ eminent for other stuff

[reef bison]

got it, thank you! 🙏

[dark parcel]

You can commit the change in client first w.o waiting for server to replicate the info back to you

Eg, request to insert item in X slot. Client commit the visual change (icons , text info, w.e) and then server rpc the request

What client change don't effect gameplay , only the visual aspect. So it may have health potion in the quick bar , but that won't be ready to use until server validate the move is valid

If the server comes back the correct data will be sync anyway

Sort of thought about it in a min, probably want to give deep thought depending on your project need

[mystic estuary]

It really depends on what exactly you are trying to do, but sometimes even a simple sound will make it to cover that ping. Character getting hurt, item being used, button being clicked, etc. It's so low effort, yet very efficient

[reef bison]

yeah I am anticipating too much a problem that I am not sure I really have at the moment

[reef bison]

that would be an easy way to do it indeed, but I would need to change all the UI logic because what drives UI updates at the moment are the replication callbacks from the inventory

actually I can just do an early update as soon as I do the RPC then the server will correct it with the callback

[dark parcel]

That's what client prediction is, you don't want your ammo count text in UI to drop only when server verify it, that will be an eye sore.

[hoary spear]

Just remember that it is prediction, not necessarily the ground truth

Only the server has the truth

[reef bison]

I got the equipment window working on the client and the server

my will to throw everything in the client is fading a bit, this is not that hard once I understand how it works

[hoary spear]

usually just gotta give it some thought

flow diagrams is my secret sauce to this

[vagrant grail]

Guys, why isn't the "Game Instance" in this graph ? Is the Game Instance server or client or both ?

[thin stratus]

The GameInstance is not a Gameplay related class. There is no multiplayer concept for it in theory.

It exists once per Game. Basically represents a bit the whole games process from start to closing it.

There is also no replication or so going on and everyone only has access to their own GameInstance

[vagrant grail]

Ah. I wanted to have a variable there containing the enabled "roles" (Among Us like game) by the player host of the game but it doesn't work properly, So I guess it's not the right way of doing that, right ?

[thin stratus]

Usually you don't want to put such information there

[vagrant grail]

Where do you suggest me putting that kind of information, knowing that the role selection is done in the lobby level before starting the game and switching people to another level and keeping that information to give roles to people ?

[thin stratus]

Lobby is already connected players?

And they select their role there?

[vagrant grail]

yes

[vagrant grail]

no, there's no role selection there for anyone but just the host setting up the game by pressing buttons to say wich roles will be available when the game start (like in this screenshot, the host of the game has game settings menu where he can press those images to turn on / off the roles for when the game starts. The greyish images are the disabled roles and colored ones will be the one enabled).

So I'm looking for how properly to save those roles somewhere to use them in the next level to distribute those roles to people.

People suggested me the GameInstance to do that as it keeps data between levels, so that's why I'm kinda confused of you telling me it's not the right place to put such information 😄

The roles will be distributed randomly to people in the next level

[thin stratus]

But that's in the lobby

You have a bunch of ways to do that. The host is always a ListenServer?

[vagrant grail]

which part ?

[thin stratus]

The host selecting the roles

[vagrant grail]

Yes

[vagrant grail]

Yes

Then he will press a "START" button when everyone and everything is ready

to go to the next level

[thin stratus]

Then I would start with turning the selection into a string and pass it via the options string

You Server Travel for that

There you can add ?rolelist=

[vagrant grail]

where do I save the string first ?

[thin stratus]

And the string could be just roleA,roleB,roleC

Up to you but you pass it via the server travel command

The game mode has a variable called optionsstring

Which will have the data then

You just have to reconstruct it

[vagrant grail]

where should I use that "serverTravel" node ? GameMode ?

[thin stratus]

?rolelist=roleA,roleB

[thin stratus]

You are already doing that

Otherwise you wouldn't be able to travel to the other level

Idk where you do that

[vagrant grail]

Not doing that yet, I have nothing to travel to the next level yet

I'm trying to focus finishing the lobby part first with all the settings

[thin stratus]

Yeah then for example the GameMode

LobbyGameMode fwiw

[maiden flame]

Sorry to inject, but why not use the GameInstance?
All the information will be set by the server, so they can just load everything from their own GameInstance after changing levels/starting the match (without worrying about security as they already have authority).
This way you can re-use variables directly (or at least transmit them to the GameMode or something), rather than having to deconstruct and reconstruct them as a string.

[vagrant grail]

We talked about that above #multiplayer message

[maiden flame]

I read that, so I'm just asking why not 😉

[vagrant grail]

The issue I have is that for some reason the variable I have in the game instance filled with enabled roles is always empty for some reason that I don't understand

[dark parcel]

That's the setup on your end, nothing wrong with GI it self

tho for something like a Game Setting, passing it as an option thru argument totally make sense?

[vagrant grail]

Could you explain to me why this setup doesn't work please ?

This is my data table

[dark parcel]

Nope but if I were in your shoes, I wouldn't do it on init

might be too early, but it's purely a guess at this point

[vagrant grail]

wheres should I do it ? 🙂

[dark parcel]

up 2 you. You can do it when you click the host button if you like

what ever your project requires

why not just use get Data Table row?

Also the property name should be Name?

not Row Name?

like where is Row Name?

actually I don't know

never used the node

[vagrant grail]

Get Data Table Row returns 1 entry while I need all the entries

[vagrant grail]

Check the image above it's called "Row Name"

[dark parcel]

there's a way to get all the rows

[short arrow]

Get data table row names -> for each loop -> get data table row

[vagrant grail]

There are 4 methods for DataTables

[dark parcel]

#multiplayer message
^

[vagrant grail]

It works, thank you so much, do you know why the code I wrote was wrong because I'm not sure to understand exactly yet 🤔

[short arrow]

I don't know what get data table properties does, seeing as you're trying to get row names anyway, I'd just get data table row names

I also noticed you are passing those values into a replicated variable in the game instance

game instance isn't replicated IIRC

[vagrant grail]

argh

[short arrow]

if there's something you're trying to replicate in game instance, dollars to donate you should probably be doing it in either the game state or you should be making a new manager class to handle whatever it is you might be trying to do in there

the easiest way is to just replicate it in the gamestate

it'll work everytime, but that doesn't mean it's always where you'll want the logic, I just don't know what you're actually trying to replicate and why

[vagrant grail]

I'm so confused, I hate Epic for having 68495 different classes

[hoary spear]

Get yourself an overview

[maiden flame]

Moxie, he needs to transfer the information from the lobby level to the actual match level.
Either the GameInstance or transferring it as a Game Setting are valid options IMO.

[hoary spear]

Or travelstring

[vagrant grail]

?

[hoary spear]

depending on what this is and how much

[hoary spear]

a class overview

[vagrant grail]

Still don't understand what it means 😄

[maiden flame]

What the different classes do, and their purpose in multiplayer. Look at exi's multiplayer documentation as a starting point if you haven't already.

[short arrow]

Then yes, game instance would be the correct place, but still no use in trying to replicate things there

Also it's a data table, its replicated by proxy @vagrant grail

[maiden flame]

Yeah, he has to move it from the instance to the GameState or something like that after changing levels. So all clients can see the roles available 🙂

[vagrant grail]

To simplify what I need with that is having the selected roles by the host save and trasfer to the gameplay level as I will need to replicate that to everyone if 1 setting is enabled (enabled in the gamesettings by the host), which is "Hidden Composition".

• If set to true, Everyone in the game won't be able to know how many roles are still alive except 1 role being the exception who will be able to see how many of those roles are still alive and ingame.
• If set to false, people will be able to see those roles on the right side on a UI Widget, and each time a role dies, it gets removed from that widget.

[vagrant grail]

I'm not sure to understand what that means 😬

[hoary spear]

how many are we talking about

cedric already suggested travelURL

[vagrant grail]

How many what ?

[short arrow]

In lobby store all information in game instance on server -> change levels -> Server RPC information from game state to clients, or transfer logic from game instance to game state and then replicate it

[hoary spear]

how many roles are you gonna need sent over from lobby

what else are we talking about here 😄

[vagrant grail]

Depends on how many were activated by the host in the game settings

[hoary spear]

Ok so:

• Host Configures the game with the avaliable roles in lobby
• Starts the game , moving everyone to playlevel
• everyone gets assigned a random role from the avaliable ones

[vagrant grail]

No, the roles are given randomly

The concept of the game is like the "Werewolves of Hollow Miller" or whatever the name in english is

[hoary spear]

fixed

[vagrant grail]

Yes

[hoary spear]

anything else?

all clients can see all "alive" roles ?

[vagrant grail]

Depends if the setting "Hidden Composition" is checked or not (I don't have that settings created yet in the game setting image above).
If it's set to true, nobody will see "alive" roles, so they have to guess except 1 role being the "Mad Man" who will be able to have that list shown to him.
If it's set to false, everyone will see "alive" roles, and the "Mad Man" doesn't have that exception anymore so he becomes like a simple Villager

[hoary spear]

almost sounds like a custom replication condition

if you truly wanna hide it from the clients (so they cant cheat it so easily)

or ofcourse just a replicated bool letting the ui show it or not

[vagrant grail]

I never used "custom replication conditions"

[lament flax]

can i get this somewhere in game ? such as in the game state or game mode ?

[hoary spear]

This sounds like a good fit from the top of my head

the data is very shortlived, per game anyways so storing it anywhere permanent seems unnessesary

[maiden flame]

GameState has a built in Players array of player states. Assuming you just need to get the player count when already in the server.

[lament flax]

I need this for a specific thing (you can think of the "supposed nb players to be here")

i am using that to only start some logic when all player are connected

in shipped game it will be handled by the host, but in editor, each time that i change the player count in the PIE settings i have to go to my game mode and change the value of a int var.

[maiden flame]

Hm, well, the default Players array changes automatically depending on the amount of connections.
Did you try using it?

[hoary spear]

Use the array as suggested

it representes the players currently connected / in the game

if you really want to use your int, you can update the int in code, by using said player array

[maiden flame]

^

[lament flax]

at server start its 0, it isnt what i need

the player currently connect is one of the 2 values i am comparing

"total player count" can be seen as the "goal nb of player before we start the game"

[hoary spear]

logic sounds flawed if so

Target vs Actual is what we're talking about

[lament flax]

then, i'll ask the question i another way

how does multiplayer games knows when all player joined the game before starting ?

[hoary spear]

target is set as a server rule for joining players, while actual is the length of the rray

so before hosting , the host would configure "public connections" , which gets used during session creation

there's also the GetMaxPlayers method, which is this very same amount

[vagrant grail]

So should I go for the game state instead of the gameinstance ?

[hoary spear]

for which part?

[vagrant grail]

to have that variable containing the enabled roles that will be distributed when the game starts

[hoary spear]

gameinstance is not replicated, so you'd need to RPC it yourself if you pick that route

gamestate is, but will change during server travel

so you'd need to handle that in some way aswell

you can route it through the gameinstance tho

All server sidie:

• Host tell Gameinstance which roles are enabled
• opens level
• GameState grabs enabled roles in the GameInstance, and sets a replicated variable in GameState.

[vagrant grail]

Is there a way where you can decide which player receives the replicated variable ?

[hoary spear]

Not easily in bp only

[lament flax]

My repnotify function is only getting called on server

Its in the game state, its set to replicate

[dark parcel]

should read it then

there are times when you want to skip owner

[lament flax]

well, the point of a repnotify function is to get called on client, now or later on

i wanted to replace a multicast with this

[maiden flame]

@vagrant grail For your game, what roles are visible to the players depend on a game setting set by the host, right? You called it something like "Hidden Composition".

If disabled, you could move the roles information from the GameInstance to the GameState, where every client has access to the information of who the roles are assigned to.
(You might handle the random assigning elsewhere, but let's keep the theory simple for now.)

If enabled, there's only one role/player that knows everyone else's role, so instead of moving the information from the GameInstance to the GameState, you can send the role assignment information to the individual player's controller or pawn, which is hidden from other clients.

[vagrant grail]

Right.

No, I don't want players to know to "who" each roles is assigned to as it will defeat the whole purpose of the game where people have to guess what role each person has.

Again, that player doesn't know "everyone else's role" as again it will defeat the whole purpose of the game. He only knows, all the roles present in game but doesn't know to who each role is applied to. 🙂

[maiden flame]

Ah, but that makes it even easier. You can still apply the same class logic as I mentioned.

[vagrant grail]

Could you reformulate it then with the info I gave please ,just for it to be clear for me because it's still blurry for me with all these different classes 😄

[maiden flame]

But you will just share the roles added to the game, not who they are assigned to.

Basically, from GameInstance to GameState = Every client may know the roles in the match (but not who it is assigned to).
GameInstance to specific controller/pawn = Only that player knows the activated roles.

Server/host handles all the information and sending it from GameInstance to GameState or the specific player who is allowed to know the active roles.

[vagrant grail]

How do you do the "Game Instance to specific controller" ?

[maiden flame]

The player associated with the role is something you do manually on the server, and we don't need to share this, only the list of roles we activated in the lobby.

[maiden flame]

Well, theres multiple ways, but you'll have to identify which player got the role that can know the activated roles.

[vagrant grail]

Please let me know those multiple ways 😄

[maiden flame]

So when the server randomly assigns roles to players, we can check if they got the Mad Man role. If the player has that role assigned, we move information about the active roles from the GameInstance to that player's pawn or controller.

[vagrant grail]

But how do you do the last part 😄

[maiden flame]

Which part specifically?

[vagrant grail]

we move information about the active roles from the GameInstance to that player's pawn or controller.

[maiden flame]

Eh, I think you should figure this out, but essentially once we change maps to the actual game level, you could use BeginPlay in the GameMode to retrieve the array of roles from the GameInstance of the server host.

Then use an event like Event OnPostLogin to assign roles from that array to each joining player (coming from the lobby).

Each time we assign a random array element from the role array, we can check if that is the MadMan role. If it is, trigger a RPC on OwningClient inside the player's pawn/controller (accessible by default from the PostLogin event output), which sends the role array from the GameInstance or GameMode (anywhere you have a copy of the list of roles ended up being used).

There's some more details, but honestly I might as well write the game for you at that point xP

[vagrant grail]

Thank you so much 😄 Yeah if you want to write the game for me it would be a pleasure so I can focus on doing the level design, UI, etc... 😄

[maiden flame]

You're welcome 😄

[rich crag]

asking again if anyone knows why a child blueprint that you cast to gets duplicated in a world partition map (if the parent blueprint is spatially loaded)? Any other situation works - if the parent is not spatially loaded, if the map is not open world, or if you don't cast. The problem is, as far as I can tell I need to do all 3, unless i place all my doors manually outside of other BP's? I cant even tell if this is a bug or expected behavior.

[maiden flame]

@rich crag It's really difficult to wrap my head around what you are trying to do. It would be best if you create a clear overview of what you want to achieve, and what your proposed solution is (with screenshots of your code). This will make it easier for someone to help you.

[quaint frost]

Hi again, did you saved UKillcamPlayback sample class? Links are not available now, i can't find an example code...

i found a solution from UT with duplicating world, but i want to implement more efficient way with FLevelCollection...

[rich crag]

Easy to explain. I have a parent blueprint (a house). It is just a collection of static meshes, plus a child blueprint (a door). I have replicated the door opening using a cast and RPC from the character. If I set the door down alone, it works as expected. If I add the door to a house in a regular map, it works as expected. If i add the door to a house in an open world map, I get duplicate doors, one on the server and a duplicate on the client that does not open. I say that because the one that opens respects collision while the one that remains closed does not. If I turn off "spatially loaded" on the house, the door does not duplicate, but this permanently loads the house, yes? not desirable. What am i missing

current door:

but i have done the door multiple ways that work outside of these conditions.

[hoary spear]

Are you calling toggle door?

[rich crag]

yes

[hoary spear]

Not shown if so

[rich crag]

calling toggle door from character with rpc

[hoary spear]

Aight

[rich crag]

on the character:

[hoary spear]

(Toggle door being rpc is redundant)

[rich crag]

but its not. different things happen

the first toggle only opens the door on the local client

[hoary spear]

You're already executing logic from the server

[rich crag]

i thought so but thats not how its working

[hoary spear]

once on the server, you stay on the server

so serverdoor already executes on server (assuming owning client etc)

and toggle door just calls on the server anyways

if you were on a client then the RPC would fail, as the client invoking this has no authority over a server owned door

[rich crag]

ok. so I've dumped the original toggle for only the server rpc, still same result.

[hoary spear]

yeah it wasnt part of a problem, just redundant

havnt gotten to any spatial loaded things yet so cannt say for sure whats going on in your case

[rich crag]

door on left is working properly, standalone. the one on the right is the same door, just in a simple empty parent blueprint

[hoary spear]

one thing i know

is that

OnRep will be client (and server) side

so you cant invoke server RPC's

you want them to be regular, local events

and the timeline doesnt need to be repliciated at all

[rich crag]

ok

[urban moth]

is there an example or at least overview how to work with GAS in MP?

[hoary spear]

Lyra / GAS Documentation / GASShooter / ActionRPG

several sample projects

no real good overview tho

GAS Documentation is the best noe imo

by tranek

https://github.com/tranek/GASDocumentation

[urban moth]

oh boy.. I thought it .. thanks anyway

[rich crag]

I didnt think those things were required (the server rpcs and the timeline replication) but as it was not working, i have been trying everything I can think of

[hoary spear]

flow diagrams help me stay sharp when doing / debugging / trailing multiplayer code

as an example

I've only recently started using 'em so they'll get better over time I'm sure x)

[rich crag]

its probably a good idea for me to start using them lol

[hoary spear]

did it help turning of RunOnServer?

[rich crag]

no. I had them off originally.

switching them back no difference

[hoary spear]

well leave them off i'd say

add some print strings and see whats going on

[rich crag]

i will, if it works the same theres no reason to do more server work

the print strings say everything is good

[hoary spear]

(the server wouldnt do it, they'd block it as client has no authority (is not owner))

what do you mean print string is good? ^^

where's the prints being executed

[rich crag]

all of the print strings in the chain report expected results

I have added them off and on through the whole logic chain

[hoary spear]

soo..

Client Input -> Server serverdoor -> Server toggleDoor

Server OnRepIsOpen -> Server Open/Close Door ?
Client OnRepIsOpen -> Client Open/Close Door ?

[rich crag]

yes

[hoary spear]

also

you're toggling door twice

[rich crag]

this is whats happining in the outliner

[hoary spear]

is the door dynamically spawned?

[rich crag]

yes i deleted the first toggle

no, the door is in a test parent blueprint that is placed

it loads the door spatially on top of the placed door

:/

i wonder if the parent were spawned dynamically

because it is showing the placed actor, then adding a spatially loaded actor

[hoary spear]

pretty strange

[rich crag]

driving me batty.

I've gone back through every replicated door tutorial i can find lol. they all do the same thing

IF in a spatially loaded parent blueprint in open world

[thin stratus]

I have never used any of that. Only shared it. The links should still work though

[quaint frost]

links yes, but there is sample code link, and it is not available, and i can't find UKillcamPlayback class source code, and it is important part of it

[thin stratus]

@pallid mesa Your Instant Replay post seems to not have all requirements available anymore. Epic sample code seems to be gone.

[pallid mesa]

@thin stratus oh no, did epic remove the original post by Alex K.

the article was an addon to the original writeup from Alex, if they have removed it i will have to rewrite the whole thing, might take a while

ah no wait, its here https://dev.epicgames.com/community/learning/knowledge-base/WjpR/unreal-engine-experimental-sample-code-for-implementing-instant-replays

[quaint frost]

yes, but this link in the end of post https://dev.epicgames.com/uploads/short-url/8HbkXKZGbi2g383QZYzbw1PCLUa.zip is not available, can you share it if you have?

[quaint frost]

and you have in your rerequisites link to it, and it is also not available

[vagrant grail]

@thin stratus I think I found a typo in your "Multiplayer Network Compendium". You forgot to add "at" between changes and runtime 🙂

[pallid mesa]

the zip is the same one that u can find in the Alex post, so feel free to grab that one

im not @ home

[quaint frost]

it is not available too 😦

[pallid mesa]

Oh my god, thats a problem

Leave it to me, i'll see what I can do, but it'd have to wait, im ooo

[quaint frost]

ok thank you in advance, i'm trying to implement it by myself, but example would be great to check )

[quaint frost]

@pallid mesa maybe you can help me then if you have written this article you should have experience, my DuplicatedLevelCollection is always null

and this method Experimental_ShouldPreDuplicateMap never called

[pallid mesa]

are you using world partition?

[quaint frost]

no, i have now single persistant level without sublevels

[pallid mesa]

which engine version are you using?

[quaint frost]

5.0.3

no game features are used

[pallid mesa]

👍 even easier

although 5.0 is a quite old version

so I have to check source code for you

[quaint frost]

we have multiplayer game with CI build system, and there is a problem to update engine, when you have modify engine source 😉

[pallid mesa]

don't worry

I will take a look in a bit, im ooo

[quaint frost]

oh it will not work in editor (((

[obtuse field]

OwO, whats this

[quaint frost]

call to duplicate levels in UnrealEngine.cpp

and removing GIsEditor check will crash the engine, maybe it should't work in editor, and check is valid here 😄

[magic vessel]

I'm working on a similar system, the way I've done it is via the game mode and by adding components to the player controller dynamically as each role has functionality that is required to run on both server and client (think assigning abilities, adding UI elements, etc). I'm using a listen server, so I'm a bit concerned that the host might be able to see these roles

[hoary spear]

Cant really get around that

[olive crow]

AActor::IsNetRelevantFor is only called from server/host to determine if it should be sent to the client right?

[lament flax]

The way i did to attribute roles to my players is by giving two params to the GM : nb of players of team A and of team B (A+B= max players in server)

Then i overrided the function "GetDefaultPawn..." in game mode to feed the correct class to the futur-spawned player

When i get back home i can send screenshots if needed

[steel lake]

Hello guys! I was wondering if any of you can help me. I'm trying to use the World's Exec() function to use the open <ip> command from C++, but it is not responding. I tried to connect using the console and it did it correctly.
What I'm doing is:

void MyClass::MyFunctionToConnect()
{
  FString ip;

  //Code to get the ip.

  const FString connectCommand = "open " + ip;
  GetWorld()->Exec(GetWorld(), *connectCommand);
}

I'll appreciate any help 🙂 Also, if this goes in other channel, please let me know and I'll move it.

[lament flax]

Even if one player is a server and client, only the server side of the player will (if you code it this way) know the roles of other players.
If the roles of the players needs to be hidden, you just have to make sure that all logics runs on client side

[steel lake]

Also, if you think there's a better option to do this, I would appreciate that too. This code is more for testing than for production.

[steel lake]

And to add more context, the tests are 100% local, so they are in my machine and I'm using the correct IP for these kind of connections 🙂

[warm scaffold]

Sanity check here 🙂
Does the ue 5.3 versus 5.0 have different port forward settings? in ue5.0.3 the port is 7777, is it the same in ue 5.3?

[quaint frost]

thank you so much )

[pallid mesa]

Removed the zip from here, as its now included in my webpage, refreshed the links with new ones.

[hardy turtle]

Hey guys, I'm trying to send this interface event to the player controller from the game state.
If i use a Rep notifier with an integer (that i update from the gamemode) it works, If i do the same thing using a boolean (wich i change every time the event is fired in the gamemode) it won't replicate.

Does anyone have an idea why?
Thank you

[quasi tide]

Should be. I don't recall seeing any patch notes saying that they changed it.

[lucid badger]

[2435.76][480]LogClass: Warning: Property InteractableComponent::bReplicates (SourceClass: ActorComponent) was not registered in GetLifetimeReplicatedProps. This property will not be replicated. Use DISABLE_REPLICATED_PROPERTY if not replicating was intentional.

Why is the log bothering me about core properties from ActorComponent?

[hollow eagle]

probably because you didn't call Super. Or you shadowed an existing variable.

[solar stirrup]

^

[lucid badger]

Yep that was it

Err the first one

frankly I'm surprised that didn't cause anything to actually fail

[sinful tree]

Is it maybe not working because you haven't connected the bool to your interface call like you have with the other variables?

[hardy turtle]

no no, i tried with that as well, it doesn't make any difference, looks like a bool doesn't replicate from the gamestate, everything else works just fine

the rep notify is just triggering the message

[rich crag]

Hi guys, trying again to see if anyone can sus my issue. Open world replicated blueprint - it doesn't matter how it's replicated. World partitioning. blueprint is child blueprint. Parent blueprint is spatially loaded. You get an extra child blueprint on (each) client only - a duplicate. it even shows up in the outliner as a dynamically spawned instance. Only the child blueprint though. And it doesn't matter if the child is spatially loaded or not. I'm trying to get open world doors as child blueprints, and it seems like this is something that would be done all the time, but I'm not seeing this issue except 2 or 3 mentions...

[rough dock]

will repnotify get called when i add or remove an item in an array?

[dark edge]

child actor component?

[fossil spoke]

Yes

[rough dock]

awesomeness

[fossil spoke]

Are you using BP or C++?

[rough dock]

bp

[dark edge]

how you make that?

[fossil spoke]

https://draw.io/ is a good diagramming platform.

If I was to take a guess.

It sounds like, if I had an "Equip Weapon" Animation

But the "Equip Weapon" functionality itself was based on a timer (instead of the Animation itself).

He would cache the time of the Animation, so that it can be passed into the timer.

That way, the Animation and the Timer completing, would be effectively the same.

Thats my guess as to what he is referring to there.

[pulsar grove]

what would be considered excessive server downstream kb/s, is there generally a good target to aim for?

[hoary spear]

Miro

Collab whiteboard

https://miro.com/

[obtuse field]

Unreal's RCPs work in the manner, that they are serialising data to be sent to the function, and then deserialising them and passing to the function on the other side, right? How can other side know where data ends in terms of e.g. instanced structs. With arrays I guess its just writing the sum length of the bits of the members, but then if its nested it has to write it again, and parent array have to take additional length bits into account

[vagrant grail]

@thin stratus typo again : site ? Instead of side ?

[hoary spear]

Not sure the tag is warranted for a typo in a widely used compendium where you get the gist of it in the context...

[vagrant grail]

I did that yesterday and no issue (he put a " 👍 " on my message). If he doesn't like to be tagged please let me know a better way to send him these typos 🙂

[obtuse field]

Also, I found out that I couldn't serialise TMap via FMemoryWriter. How is it serialised for e.g. saving?

[thin stratus]

FInstancedStruct probably calls NetSerialize on the inner struct

[obtuse field]

But it still have to send info about inner struct type. Anyway, how can I serialise type reflection?

[thin stratus]

Yeah FInstancedStruct probably has its own NetSerialize for that. Iirc James also said it shouldn't be used for stuff like Inventories or so. Probably due to the overhead.

[obtuse field]

My whole plan is to use it for inventories, lol

[thin stratus]

Rip

[obtuse field]

Somehow I have to save items custom data

[thin stratus]

The usual way is UObjects

Jambax posted somewhere how he does arrays

FastArraySerializer with UObjects

Exact setup depends a bit on the project

#multiplayer message

There is also a post somewhere with some pseudo code but it would be the same stuff he wrote there just as code

Inventories work differently, so this isn't a solution exactly for all inventories. Some might not have stacking or need each instance in a stack to be unique. Would need to adjust the info per FastArraySerializer Item to match your requirements.

The UObject instances must be replicated via some actor. Usually the outer of the Inventory Component fwiw

[obtuse field]

I will take a look later, ty

[obtuse field]

ik

[fossil spoke]

Im putting together an Itemization plugin for my own exploration that uses them and datatables. I have yet to profile it at all but i am curious what the real overhead would look like. Id concede that a UObject approach would definitely be more efficient and probably easier. Im still curious to see what it means to use them in a context like that.

Ive noticed some issues with the current implementation of FInstancedStruct that could be improved upon.

But they are a cool concept

https://github.com/mattyman174/GenericItemization

[thin stratus]

Hmmm. I wonder. For a UObject it'd send net Id and whatever property got changed.

FInstancedStruct might send the inner struct class and all data of the inner structure all the time? Not sure.

[fossil spoke]

It for sure does. If you are doing constant changes it would be a big issue.

But realistically Items dont change much beyond their initial creation.

Im only curious to see what the implications are for using FInstancedStructs in this way are.

Not convinced its an appropriate usage.

But im developing a usable system and will profile it in a somewhat realworld usecase. Like an ARPG setting for example

[upbeat basin]

How much does cheaters have control over our games? I always assume any variable can just be changed locally. If we take the simple example of opening/closing a door with a replicated bool with on rep function, where the door's rotation changes locally in the on rep function according to the bool's new value, would it be possible to open the door locally, since it's bound to the OnRep function and not the bool directly? Or wouldn't they be able to just change the rotation of the door? Since it wouldn't be open on the server, they wouldn't be able to walk past it since the server collision would prevent the movement. But they could still see inside if we put something that's supposed to be hidden behind the door. And thinking like this, wouldn't it be just possible to change materials to have wall hacks?

Are these inevitable things that could happen without an external/third party cheat protection or are there things that we can do more than server authoritive logics to prevent cheating?

[chrome bay]

It does yeah. FInstancedStruct does no delta replication and is always atomic, even if the internal struct isn't.

Unfortunately delta replication is extremely hard to do because the underlying struct type can change at anytime, which makes it very difficult to store any history state and/or ack receiver packets. Iris might make it possible since delta serialization is somewhat automatic in a sense, but not sure yet.

Just a general comment but for me the common design issue I see with inventory systems is people pack all their "item" data into a single "item" struct, which then has to contain all properties for any inventory system concept, like "stack size" or "level" or whatever. It's just a classic inheritance problem where the base has to include data types used only by certain children.

[fossil spoke]

In the plugin ive opted to separate static data from dynamic data in the form of ItemDefinitions and ItemInstances. Instances of Items are generated from Definitions and are what is replicated and they only ever replicate the dynamic data that is specific to the instance that cant be stored anywhere else. Minimizing as much as possible from being replicated. There are still far more optimizations that could be made but as i said earlier ive yet to really do any profiling and earnest optimization.

ItemInstances do replicate a handle to the ItemDefinition so that they can access the static data about themselves.

But the fact they are serialized in full is hard to escape.

[hoary spear]

I keep a single handle for the static data, which clients fill into the struct themself (for userfriendlyness), but i havnt found a good way to solve custom persistent data without stuffing it into the base struct.. feels like i cant get around that

[reef bison]

I have a UPROPERTY(Replicated) TArray<FExample> Example array in my ACharacter class. I only change the value of this array in the server and it is only read by the server. I removed the Replicated flag and everything seems to be working fine

I want to make sure I got this right: everything still works because since I only interact with this variable in the server, there is no need to replicate this value back to the clients

if I ever forget about this and try to access this variable in a code path that runs both on the client and the server, then I would have a divergence in values, right? (the client would always see it as empty)

[warm lintel]

yes

[reef bison]

thanks

[hoary spear]

Just slap a blueprintauthorityonly specifier on it 😄

[obtuse field]

So, I'm trying to send data 2 times in a row over TCP socket

TArray<uint8> Bytes;
    FMemoryWriter MemoryWriter(Bytes);

    TMap<int32, FInstanceBuildingData> PlacedInstances;

    TArray<int32> TestArr;
    TestArr.Add(14);
    TestArr.Add(15);
    TestArr.Add(16);
            
    MemoryWriter << TestArr;

    int32 BytesSend;
    
    if(!Socket->Send(Bytes.GetData(), MemoryWriter.TotalSize(), BytesSend))
    {
        UKismetSystemLibrary::PrintString(GetWorld(), "SEND ERROR");

    }

    TestArr.Empty();
    
    TestArr.Add(30);
    TestArr.Add(31);
    TestArr.Add(32);

    TArray<uint8> Bytes2;
    FMemoryWriter MemoryWriter2(Bytes2);

    MemoryWriter2 << TestArr;

    if(!Socket->Send(Bytes2.GetData(), MemoryWriter2.TotalSize(), BytesSend))
    {
        UKismetSystemLibrary::PrintString(GetWorld(), "SEND ERROR");

    }

But only first array is displayed. Although, it how bits for 2 arrays (PENDING DATA, READ DATA)

This is how data is read on the client:

                TArray<uint8> Bytes;
        Bytes.SetNum(4096);
        
        int32 BytesRead;
        
        ESocketConnectionState SocketConnectionState = TCPChunkDistributor->GetConnectionState();

        if(SocketConnectionState == SCS_Connected)
        {
            UKismetSystemLibrary::PrintString(GetWorld(), "CONNECTED");


            uint32 DataSize = 0;
            TCPChunkDistributor->HasPendingData(DataSize);

            UKismetSystemLibrary::PrintString(GetWorld(), "PENDING DATA: " + FString::FromInt(DataSize));
            
            if(!TCPChunkDistributor->Recv(Bytes.GetData(), 4096, BytesRead))
            {
                UKismetSystemLibrary::PrintString(GetWorld(), "ERROR");
            }
        }
        if(BytesRead != 0)
        {
            UKismetSystemLibrary::PrintString(GetWorld(), "READ DATA: " + FString::FromInt(BytesRead));
            
            FMemoryReader MemoryReader(Bytes);

            TArray<int32> TestArr;
            MemoryReader << TestArr;

            for (auto Arr : TestArr)
            {
                UKismetSystemLibrary::PrintString(GetWorld(), "ELEM: " + FString::FromInt(Arr));
            }
        }

[fossil spoke]

What has this got to do with #multiplayer ? This is a #lighting question…

@obtuse field Did you also mean to ask a question?

[obtuse field]

Yes. I might have stated it a little unclear, as the problem is, I send 2 arrays, and only 1 is displayed, but I think I know what might be the issue

[obtuse field]

I guess this is how MemoryWriter reads the data. First 4 bytes shows how many elements are in the array, and so it reads only another bytes that are within the bound of what these first 4 bytes show, e.g. if the value is 2, then it will read 2 * sizeof(element) bytes

But, is there an easier way to deal with it, than keeping track of all the data? Isn't there something to e.g. automatically divide these chunks?

[fossil spoke]

My suggestion would be to try and search for similar usages across the engine source code and analyze how it is managing this process. The best documentation is the source code itself.

Sorry i cant be more helpful. Im about to go to bed 😄

[obtuse field]

Good night then

[thin stratus]

Has anyone tried out NPP and run into checkf(false, TEXT("No matching simulation data found for TraceID: %d"), TraceID); when opening a Trace with NP Channel in it?

[true cliff]

Hello. I have a question. I'm making a game with MediaPipe. Is it possible to replicate motion capture pose in local multiplay?

[solar stirrup]

That's awesome

I use instanced structs for items as well

In our case item instances have a TMap<FName, FInstancedStruct> so you can get/set data by name

however recently changed to it a TMap<UClass*, FInstancedStruct> where the class is a special object type that just returns a UScriptStruct

With custom net serialization, I only read/write the UClass* and then the FInstancedStruct's underlying data (skips serializing the UScriptStruct for no reason since we know that it'll be from the UClass)

[hoary spear]

Thats just static data tho, Right?

[gloomy tiger]

Have this on my AGameState:

UPROPERTY(Replicated)
float Value = 0;

void SetValue(APlayerController* Instigator, float NewValue) { Value = NewValue; }

Is there any way to replicate Value to all but the Instigator? Reason I ask is because the Instigator already has its own local version of Value; also, I'd like to keep it as a replicated UPROPERTY() to automatically benefit from replay et al.

[chrome bay]

There's not no, not unless you move it somewhere else

[gloomy tiger]

Aight, thanks.

[vagrant grail]

Is the data in the gamestate getting reset when switching from one level to another or does the data stay ?

[rich dune]

Hey,

on P2P sessions on map change, clients disconnect for some reason. we use seamless travel and the same code works perfectly fine on Dedicated Servers. It even works perfectly fine when I hoste a P2P Session on my Switch Dev Kit and join as client out of the editor and the transistion works fine.

Any ideas whats the issue?

This is how we change the map currently: https://blueprintue.com/blueprint/ermobq61/

[hoary spear]

So which scenario doesnt work fine ?

[thin stratus]

GameState gets recreated.

[vagrant grail]

Thanks, Is it possible to contact you in dm to get infos about hiring you and your studio to make a game ? 🙂

[thin stratus]

You can check my Discord Profile for an option to contact us.

--

Man, Network Prediction Insights is totally busted for whatever reason

[vagrant grail]

Argh, wanted to use a direct message app so we can talk to each other so I can explain to you the project and if you have questions you can ask me to get more infos, etc... 😄

[thin stratus]

Hehe, yeah no, initial contact and all of that via email please.

[vagrant grail]

alright 😄

[thin stratus]

Assertion failed: false [File:E:\UE\Engine\Engine\Plugins\Runtime\NetworkPredictionInsights\Source\NetworkPredictionInsights\Private\NetworkPredictionProvider.cpp] [Line: 410]
No matching simulation data found for TraceID: 10

sigh

[lost inlet]

I thought NPP itself would get a bit more love than it has with Mover being actively worked on

[thin stratus]

Yeah seems to be an NPP related problem. I can repro that with any kind of Simulation running, even the NPP examples (the flying UFO).

Bummer, I was about to modify NPP to add some stuff, but can't validate if it works without the Insights debugging.

[lament flax]

if i spawn a actor on the server, will this be replicated to the clients ?

[dark edge]

if it's a replicated actor yes

[lament flax]

perfect, ty

[vagrant grail]

How to transfer all the player to a new level please ? I tried to use "Open Level" on the host it moves him but it kicks the other client for some reason 🤔

[solar stirrup]

UWorld::ServerTravel

https://dev.epicgames.com/documentation/en-us/unreal-engine/travelling-in-multiplayer-in-unreal-engine#uworld::servertravel

[vagrant grail]

I'm in blueprint

[solar stirrup]

Execute Console Command -> ServerTravel YourMap

[thin stratus]

?listen is redundant there

[solar stirrup]

ty

[vagrant grail]

doesn't work 😬

[lament flax]

Maybe you have to give a path ?

Maybe call this in server

And not client

[thin stratus]

don't think so, but has to be called on the server

[dark parcel]

Mb didn't read the message

[vagrant grail]

Ah

[thin stratus]

And the listen part isn't needed

[lament flax]

Why?

Just curious

[thin stratus]

Cause it's not

[hoary spear]

Its implied

[thin stratus]

Like ,it's not needed :D

Not even that, ?listen is for OpenLevel to start listening for incoming connections

ServerTravel doesn't need that

[lament flax]

because its already in "listen mode" ?

after first Open

[thin stratus]

Yes

[lament flax]

okay ty for explaining

[hoary spear]

Thats what i ment tho, its implied thay you're a server when you do a servertravel

[vagrant grail]

Where's the best place to put it on the server ? In the gamemode ?

[lament flax]

doesn really matter, but maybe you want to create a reusable event to change level

in this case you would want to place this event somewhere easy to access

[vagrant grail]

PlayerController then ?

[lament flax]

idk, you decide

:)

[vagrant grail]

it doesn't help 😭

[lament flax]

can be anywhere server side

[vagrant grail]

That's why I hate Unreal because there 600 manners to do things 😦

[lament flax]

i would probably place this in game state

[thin stratus]

It really doesn't matter

[lament flax]

its a good thing, the more its customizable, the better

[vagrant grail]

No because it confuses people even more (that's my case)

[thin stratus]

Also that argument goes for a lot of things, not just UE

[lament flax]

true

[vagrant grail]

what do you mean ? 🤔

[thin stratus]

Being able to do things in a lot of ways

Is not a UE "problem"

[lament flax]

btw, whats the diff between game instance and game state
each time i do some research i get more confused

[vagrant grail]

But UE has that problem

[thin stratus]

You call it problem cause you lack knowledge at this point

[vagrant grail]

you see

[lament flax]

UE has that super ability to be used in any way you want

all programmer tools have this

[lament flax]

once you learn its great

[wary marsh]

Noob question here. I couldn't think of a better way to ask the question than just to make a video. I'm pretty stumped. it seems like should be a simple thing that I'm just not considering.
Any help would be greatly appreciated.

[lament flax]

when you start you always lack knowledge

[vagrant grail]

true but people with knowledge will still come up with different answers, so that's not good for newbies trying to learn and seeing people saying different things

[thin stratus]

GameInstance exists once per Game Process, shouldn't be used for Gameplay fwiw
GameState exists once per "map/world" and allows replication from server to client and should hold the game's current overall state

[thin stratus]

It's still not an actual problem

[vagrant grail]

I promise you it is, they should simplify it

[thin stratus]

Cause it means that you can solve it in multiple ways without having to worry if it's the ONE way

There is nothing to simplify here

The classes that exists in the GameFramework all have their right to exist

Where you put your ServerTravel call is completely up to you

[vagrant grail]

But there are so many

[thin stratus]

Yeah and that will always be like that

You gotta learn them

[vagrant grail]

snif 😭

What I would really like is to have something as simple as 2 contexts, server and client. And you can't code server stuff in a script inside a client context, and can't code client stuff in a script inside a server context, so you can mark a real split between client and server in terms of organisation.

[lament flax]

weird indeed

[solar stirrup]

Except that's code duplication hell

[hoary spear]

Welcome to programming

[solar stirrup]

You'll just get the hang of it by learning

[hoary spear]

Programming principles exist to guide you

[lament flax]

okay ty

[thin stratus]

I mean, sure, but you will quickly notice that this doesn't work for everything and everyone

as soon as you have ListenServers, you will have duplicated code

[vagrant grail]

the issue is the "learning" part as you can't learn stuff properly because everyone makes tutorials in a different way

[thin stratus]

Online Tutorials are very often really bad

[lament flax]

thats why you leanr by doing mistakes :)

[thin stratus]

No matter what it#s about and how simple or complex the topic

Cause people make tutorials based on wrongly learned knowledge

[lament flax]

when i look back at my first projects, damn everything is bad xD

[thin stratus]

And spread it

[vagrant grail]

yeah and one of the reason is because there's 600 ways of doing stuff

[thin stratus]

¯_(ツ)_/¯

[lament flax]

no interfaces, all hard cast refs, no parent child stuff

[solar stirrup]

Filter those ways to "good" ways and there will be less

Even then, flexibility is awesome

Projects have different requirements

[lament flax]

a single DT with hundreds of lines

[vagrant grail]

https://tenor.com/view/smart-think-meme-intelligence-common-sense-gif-8946867

[frail barn]

i have a pawn, which is Hidden in game. how to unhide it for only one specific client, still remain it Hidden for other clients?

[lament flax]

when the video is 30+ min long and the guy has a powerpoint i generally feel in good hands :)

[vagrant grail]

There are 600 ways to do that, pick a number between 1 and 600 to choose which way you want to proceed 👀

[lament flax]

call the "set hidden in game" on client

[thin stratus]

First wrong thing: PlayerController -> GetGameMode -> ServerRPC

BeginPlay will already call on the Server AND on the owning Client

If you filter for "Authority" you wouldn't need the RPC

And you will probably get accessed none atm due to getting the GM on the Client (if you use it)

[frail barn]

thats unhide pawn for all clients for me
how to do it properly?

[lament flax]

set hidden in game asks for a bool
true : hide it
false: unhide it

thats why its called "set hidden" and not "hide"

[lament flax]

from what do you want to hide it ?

are you on client side or server side when you decide to unhide an actor

[thin stratus]

Second problem, in theory, your PossessedEvent -> Change MID stuff needs to be done via RepNotify variables. Possessed only calls on the Server and those events won#t replicated by magic.

[vagrant grail]

You have a method called "Set Only Owner See"

[thin stratus]

Third note: "Playing with multiple clients makes the first hosting client not work". You hovered "Play as Client", and if you meant that with "mutliple Clients" then that's not even a Client hosting anymore in that mode. That's a DedicatedServer setup. So if the first client there fails, then it's not even a Server vs Client issue.

[thin stratus]

Despite all of this, you seem to be player singleplayer in your test and that already doesn't work.

Not entirely sure why atm. Setting the DefaultPawnClass makes no difference, cause your PlayerController BeginPlay will replace the Character anyway

[thin stratus]

Another point is that you are getting the GameMode on BeginPlay, and you use it "later". I would suggest you get the GameMode and cast it when you need it and not earlier.

But that shouldn't break anything of course

I assume you are using EnhancedInput for the actual movement

So I would suggest you check via "showdebug enhancedinput" if the keys are even working at all when you play

cause they aren't, then whatever logic you have to set InputMappingContext etc. is probably broken

[wary marsh]

Thanks for the information, I'm absorbing this :D. I will look at the input mapping stuff I am using the enchanced input mapping. But imp pretty sure that its working because it responds to input on the clients. I was looking to see if there was some setting for multiplayer for those but definitely don't see any 😛

I originally wasn't calling the game mode cast on begin play. I moved it there while trying to figure out why it wasn't working correctly

Yea I assumed the Travel to map with "listen" effectively converted the client to the server. But I connected 3 other clients to the same session and all the connected players moved and replicated their montages

[thin stratus]

You are playing Standalone in your video

Unless you specifically check "isServer" or so somewhere, multiplayer doesn't at all matter here

[wary marsh]

im under the impression that "standalone" is more or less the same as being the server all teh time.
But its the same issues if i play as listen server or purely as clients
whomever is considered the server cant move if if i run the event begin play command

[thin stratus]

@wary marsh Standalone is not a Server. It would actually fail IsServer checks.

And "purely as clients" if you use Play as Client in the settings, is with a DedicatedServer

No one hosts there

It's a headless process without graphics that is the server in that mode

So if the first client can't control, then it's not a Server vs Client issue

[torpid storm]

What I would add, is that there's a lot of stuff going on in that video. Plenty of different places where things could break. Try to reduce it down to a simpler scenario. Standalone should work if you've been careful to check authority rather than explicit client/server stuff. If not, Listen Server should be okay. No need to test with 2 players.

[wary marsh]

Play as Client works just fine I get 2 clients that work as you'd expect it to.
But then when i click Host game.. the logic is Open Map option-- listen
Then the screen that says client1 wont accept inputs
But the screen that says client 2 (the person who found the session and joined) works as expected

[thin stratus]

Eh

If you go through the host game logic of a main menu

You should not have it say client

That means you started the main menu with PlayAsClients

Which means they are already connected

If you want to test connection process, you gotta start 2 players with Play as Standalone selected

[wary marsh]

hmm. i see. So if i 2 standalones. then host with one and connect with the other it would be a more proper server client relationship?

[thin stratus]

At least closer to what players would experience

Wouldn't explain why your character in standalone can't be controlled

But I alreayd told you to check the input debug

[wary marsh]

yea ill move on to that. 😄 thanks for your help!

Okay... lol feel like an idiot... but i initialized the enhanced input in the player controller and not just on the pawn.
this seems to have solved the issue.

thanks @thin stratus

[lament flax]

random question

when you plan your game to mutliplayer, with the server as a dedicated one
there is a "build" version for the server right ?

is there some resources on how to config dedicated servers for unreal ?

[torpid storm]

What do you mean, a build version? There is a versioning system, certainly. There's also some checksums which can detect when things are out of sync. I don't have much experience with either though

[lament flax]

i am taking about a special exe build or whatever for the dedicated server

i am not talking about versioning

[torpid storm]

https://dev.epicgames.com/documentation/en-us/unreal-engine/building-unreal-engine-from-source
You can just pick a server config as opposed to editor or client or whatever

[lament flax]

we arent understanding each other ^^'

[hoary spear]

versioning in this context is not to be confused with source control.

[warm lintel]

Yes, but that's not a called a version in this context

https://dev.epicgames.com/documentation/en-us/unreal-engine/setting-up-dedicated-servers-in-unreal-engine?application_version=5.0 docs page for lack of a better resource

[lament flax]

sorry

[lament flax]

ty

[warm lintel]

there were some stuff on the community wiki as well IIRC

[torpid storm]

You said " a special exe build or whatever for the dedicated server", I posted the docs for producing an exe of a dedicated server, so I'm not sure what the issue is here.
Blue's doc is better, sure. 🙂

[lament flax]

sorry, i kinda stoped to the title of the doc

i didnt understood the link between building from source and a dedicated server

[torpid storm]

All good 🙂

[graceful flame]

If you wanna make a dedicated server for your multiplayer game you have to build it using your IDE (visual studio). You can't build it using the epic launcher version of UE.

The process to generate a server build is quite simple, you just have to change a single drop down then right click and press build, but this all happens within visual studio which means you need to download the UE source from github and compile it first also using visual studio.

[quaint frost]

@thin stratus thank you for links
@pallid mesa thank you for great article and help with example code
Now i implemented instant replay and it works, have some problems with camera but i think i will solve them myself. @pallid mesa can i contact to you in PM? about replay system i have another level task, want to know your opinion 😉

[hardy turtle]

Hey guys! What am I doing wrong? i really don't understand, i select my character in the menu, it saves on the gameinstance in a data asset, the pawn gets it from there and it should replicate to the others right? it does not for some reason 😅
Hope you can help! Thanks in advance!

[thin stratus]

If you set it in the Menu and save it on the GameInstance, then you are missing the part where you tell the Server the selection

Using BeginPlay ( which calls on everyone .. ) to set it is not enough and specifically wrong, cause that way you will always have the Server set it to its own value

[lament flax]

you can edit data assets at runtime ?

[thin stratus]

No

[hardy turtle]

oh i see, that's true

[thin stratus]

DataAssets are ReadOnly, at least in 99% of the time

[hardy turtle]

yeah you can, i do it for the character selection and some other stuff

[lament flax]

didnt know you could do that

[thin stratus]

You 100% shouldn't

[lament flax]

i dont see the utility for me tho

[thin stratus]

The changed data will also not replicate

[lament flax]

and sems kinda illegal xD