multiplayer

[thin stratus]

And set the Actor location

And then only on the Server

but it will look choppy on the client

[leaden sparrow]

these are checked

[leaden sparrow]

i dont know how to do this praticcaly

[thin stratus]

Limit BeginPlay with SwitchHasAuthority to only us the Authority pin

[obsidian basin]

So if a variable is replicated from a player state, it's stored on the player state entry in the player array. If it's replicated from a pawn, where is that stored on the server? Rather, where can it be retrieved from?

[thin stratus]

From... the Pawn?

[leaden sparrow]

i have no idea what does that mean

how to do that

[obsidian basin]

What if I need to change that variable? I send a message to the server with what identififer for the pawn?

*identifier

[leaden sparrow]

?

@thin stratus

[thin stratus]

Yeah something like that

[leaden sparrow]

let me check

[thin stratus]

But you need to set ActorLocation

Not Relative to make that work

[leaden sparrow]

so i have to clear the work i made with timeline and make it with actor location?

[obsidian basin]

I know it was mentioned earlier about a uniqueNetID, but I'm unsure how I would get that for an actor

[thin stratus]

You are using SetRelativeLocation

Just swap that

[thin stratus]

I think you are overcomplicating something here

No one touches NetIds for this

You get the reference to that Actor in question and change the Variable

And if it has to be on the server, then the server needs to get that

[obsidian basin]

I was under the impression that actor references were unique to the client, though - is that not hte case?

[thin stratus]

And if the local client wants to tell the server to change a variable in its owned actor, it uses a server rpc

Idk what that means

[thin stratus]

Yeah there is no need to connect that as you are inside the actor already

"self" is the actor

[leaden sparrow]

oh ooookay

compile save lets check

[thin stratus]

You seem to have a knowledge gap surrounding what references are and how they work

Getting a Pointer (In BPs reference) to a Actor or any Object is either done by making sure you save it to a variable somewhere already accessible

Or if it's an actor that has collision and it makes sense context wise, you get it via an overlap, a linetrace, a hit etc.

E.g. a Projectile hitting a Character

If you have that Reference, then you can change your variable

Multiplayer just adds more to that concept

If you have a reference to an Actor on the Server side and that actor is replicated, you can use Multicasts to trigger events on the replicated instances of that actor, or replicate some variable

If you have a reference on the Client and the Actor is owned by that client, you can perform a Server RPC

As well as target that client from server side with a Server RPC

If you have an Actor that is not owned by that client, you have to go through another actor that is owned by the client, otherwise you have no way to tell the server to change the variabl

E.g. a Door in the middle of the map can't just execute Server RPCs

[obsidian basin]

Youre right I think I did have a gap

[thin stratus]

Another example is, if you have a variable on your Character, and you want that to replicate to everyone, and you want to increment that every time you press the E key, you use a Server RPC (cause a Possessed Character is owned by that client) to tell the Server to change the variable

In a lot of cases, you only ever use a Server RPC to tell the Server about an input that happened

Maybe it be a controller, keyboard, or a UI button press

After the ServerRPC, you are on the server and you can then do whatever you want there

e.g. Left mouse Button to fire a Gun, ServerRPC_FireWeapon

Then on the Server you do your LineTrace or spawned a Projectile

And when it hits you damage whatever you hit

[leaden sparrow]

it works fine thanks but now the problem is when i put the cube where i want in the editor it goes different location like this

[thin stratus]

Since you are still on the server after the RPC (if no other RPCs get involved) you can modify a health variable that is replicated in some other character that your line trace hits

But that's specific the context of firing a line trace weapon

There is no one solution for getting references etc. It's a matter of understanding the basics, the tools, and using them

[thin stratus]

it's because your Timeline uses a location that is relative

Before start your timeline, get the ActorLocation and save it to a variable

And then instead of directly using the timeline value on the SetActorLocation node, add it to the variable you created

So you have "SpawnLocation + Relative Offset" basically

Otherwise you will always have that cube at Relative Offset to World 0,0,0

I must honestly ask why you are trying to do a Multiplayer project if you can't set a variable

Like, no offense, but this seems really the wrong approach

[obsidian basin]

I think that's a pretty good example - my only difference is I'm trying to do an RPG style attack where I press a button and my character damages a selected character, so I guess I just need to know what character I have selected and pass that information instead.

[thin stratus]

Yeah, just keep in mind if you send the select Actor via the ServerRPC along, it allows for cheating

Cause then a player can select someone out of range

So you need to double check

It's better to send a blank RPC to perform the Attack

And then do the targeting on the server

Whatever that might be for your attack

Yeah but then please learn the basics a bit more

Getting and Setting Variables is really the most fundamental thing in the Editor

I gladly help you with network issues, but this is a bit much

There are tons of tutorials you can watch and read for basics

[obsidian basin]

Hmm, I think I see what you mean. I was storing the targetted character as an RPC on the player state, but I can see how that could be exploited.

[thin stratus]

PlayerState is also not really the place for this

[obsidian basin]

So I'm learning

[thin stratus]

Your Character is the one attacking after all

[obsidian basin]

I had a lot on the player state, but started moving a lot of it off.

How would you check for targetting in a game where you explicitly have to 'select' someone, though?

Sorry, more of a rhetorical question

[thin stratus]

When using UE you have to first understand that it's heavily inspired by the original Unreal Tournament Game, where a PlayerState held Name, Kills, Deaths, etc.
Data that has to be known to every connect player to show it in some scoreboard.

Doens't mean that's the only way to use it, but sometimes some classes just aren't useful to something that isn't Unreal Tournament.

Again, PlayerState is super useful, but it's meant for data that other players have to see regardless of where the player is and if they have a character or not

[thin stratus]

The idea would be to send the minimal amount of information to the Server that it needs to select

[obsidian basin]

Yeah I had some data on there that other players are meant to 'see'

[thin stratus]

If it's targeting via mouse selection, then you could send the select actor and the mouse location via the RPC

Server could then double check if there is really EnemyABC under the mouse

[obsidian basin]

Which I guess I could do similar to a line trace?

[wooden plover]

Where would you go for the basics? I've been doing a bit of BRY watching on Youtube but his series stopped at 4(multicasting) and hasn't released the part 5 for his series.

[thin stratus]

I'm a bit out of touch with tutorials now a days as I rarely use them. Not sure I can recommend anything

[gloomy tiger]

Hey.

Question: I am dealing with a very simple multiplayer mechanic: shooting. I raytrace from the middle of the client's screen and send it to the server so the server can do its thing. Working great.

However - is there any way to get "the middle of the screen of the user" without relying on the client transmitting that info through the network?

[digital marten]

Why are my players not replicating their transform?

The server/client will replicate to all connected clients, but the clients won't replicate on the server/client.

Replication is enabled, so I don't know what's going on. I'm not getting any errors.

[woven basin]

I’ve been following this chat for the past week. I’m going to need sprint+GAS myself soon, and I’m very confused how/why this is not a simple “solved” thing. I never would have thought of half the issues faced - Seems so fundamental?

Would love if you get time to blog a summary of the final outcome on how best to handle this? I’m sure others would benefit too.

[woven basin]

No, because how else would the server know? You could maybe use the server to guess based upon the player location and rotation, but for a shooter it will be slightly laggy by a few frames.

Why would you not want the client to tell the server the exact spot it was looking at with the fire command?

[digital marten]

I'm using a CPP pawn and the moment code is cpp. I implemented FloatingPawnMovement component from the blueprint not in C++

[woven basin]

If you want a good c++ MP course, Stephen Ulibiri has a good one on Udemy. It’s great quality (unlike many others). Has regular discounts coupons on his Discord, totally worth it.

Tom Looman has another one, more expensive, but also high quality.

[obsidian basin]

So I THINK I have this figured out, but mind double-checking m work? So I have an input action that does a Get Hit Result Under Cursor for Objects. I then call an RPC and pass in the local controller as well as the hit result. On the RPC, I do the same thing passing in the controller and then compare that actor result to the passed actor result. If it's true then I have the target.

Target is then stored on the server until it's cleared (so any attacks/etc are just directed to it)

Oh wait, it's failing... nevermind

[leaden sparrow]

@thin stratus 😎

[dry pebble]

I'm still lost lol, wish I could write a blog on it. I have sprinting with stamina on the CMC which drains while sprinting and has a 50 cost with jumping and dashing. And then it regenerates too. I've just connected it to a UI, but it only syncs to the server with a net correction (which hardly happens).

So I'm currently stuck on not being able to predict Stamina, so the server and client are way off. I have the stamina drain with veloicty * a modifier but regenerating it needs to be done while standing still so have been using deltatime. But it seems the server and client regenerate at different amounts because of that so their gap is so far.

If anyone has any idea how to predict stamina on the Character Movement Component, or has any ideas I might be missing, I need the help 😄

Unless most people don't use CSP for things like this and just get the server to send down the final result and only update UI once it's recieved? I may be looking too much into it lol

[hollow eagle]

Server and client being way off seems odd - is this under pretty bad network conditions?

With minimal network simulation, and even if doing pretty simple prediction they shouldn't be far off if it's something like Stamina += DeltaTime * SomeConstant

Or is the issue that the server is constantly correcting the client? What you want to do there is make it so the client value isn't directly updated by the server but instead only corrects itself over time or if the correction is too large.

[austere burrow]

Hey all, is there any reason for custom events in a GameMode blueprint to be marked RunOnServer? It seems redundant because the GameMode only exists on the server? I followed a tutorial series that does this many times and (while everything works) I want to check my understanding and simplify my BPs if possible

[fathom aspen]

There is none, it's a bad practice

GameMode is inherently server-only and it doesn't replicate in the first place, so yeah

RPCs are out of the picture

[austere burrow]

OK great, thanks for helping with my sanity check lol

[fathom aspen]

Also fwiw Epic multiplayer tutorials does worse than that, as they in fact do stuff that basically don't work™️

[austere burrow]

this was an official epic tutorial series ha

[obsidian basin]

Is it possible to call a get objects under cursor on the server? Or do I need to do a line trace?

[fathom aspen]

Great, you proved my point

[fathom aspen]

It's possible wherever there is a local-controller

[obsidian basin]

SO pass in the local controller as a reference and put it on that?

[fathom aspen]

No, because the other end won't get that local-controller but instead its Net GUID

And in return it's corresponding version, which is 100% non local

You do it locally

You pass the results

[obsidian basin]

How does the server ensure you're not cheating, then?

[fathom aspen]

That's another question, and the answer lies in doing the line-trace on the server. The server could keep track of the location of the cursor for example

So in fact you would end up doing the line-trace on both client and then on server

No need to RPC if the client is not cheating

You only RPC if things are "getting out of order"

[obsidian basin]

So why not just use a line trace in both instances?

[fathom aspen]

Because that would be gross for bandwith

[obsidian basin]

Gotcha

[fathom aspen]

The less you RPC or replicate data while getting your desired results the better

[obsidian basin]

So get results, pass that to the server in an RPC - Server needs to do... I guess a line trace from camera to cursor's V2 position?

[fathom aspen]

I have no idea how that function works

You will have to look what they do

But yeah camera must be involved and actually you could take advantage of that

So for example the server checks if the thing that was hit could exist by the FOV on server

So no cursor-location tracking whatsoever

[austere burrow]

sigh ok so my multiplayer lobby has everything being replicated through player controllers and it seems like PlayerState would make a lot more sense?

[obsidian basin]

This definately seems like one of the more complicated RPCs to execute.

[fathom aspen]

Yeah and it smells bad

[fathom aspen]

Well it depends on what properties you're storing. There is no such a class that should store all replicated properties

[austere burrow]

Yeah fair point. PlayerState is not utilized at all however and I think it would make sense for a lot of properties. Need to do more research

[fathom aspen]

Honestly all you need is to understand what every GameFramework actor is responsible for

Multiplayer Compendium for example does a good job at explaining it

This too: https://www.tomlooman.com/unreal-engine-gameplay-framework/

[austere burrow]

cool, thanks for the link

[dry pebble]

even on 0 ping, the client was stamina 100 and server 50 catching up. Not sure why, it was like the server ticked so much slower than the client, even just in PIE, play as client. Any ideas what could cause that?

[hollow eagle]

That seems like a bug with how stamina is being calculated - single process PIE with no network simulation should not be that far off.

And it wouldn't be down to deltatime differences - I don't think there'd be any in single process PIE anyway.

Sounds more like the server is doing something the client isn't, or vice versa.

Random possibilities to look out for:
Something else affecting stamina on the server (or client) that shouldn't be or isn't predicted.
Server stopping some operation too soon/too late compared to the client.

Some other multiplier on the server being different than the client.

[dry pebble]

I was doing in UpdateCharacterStateBeforeMovement for stamina regen

if (!IsSprinting() && Stamina < 100.f)
        {
            const float StaminaRegen = 10.f * DeltaSeconds;
            Stamina += StaminaRegen
        }```

[hollow eagle]

Not a huge amount to go on here unfortunately. Just spitballing at the moment.

That at least does look fine

Something I'd do to debug is have the client store its stamina somewhere else every frame, and when it receives an OnRep for new stamina from the server print the difference. Just to confirm what kind of corrections are coming in.

[woven basin]

Are you doing this in PlayerState, which has a slow replication by default?

[hollow eagle]

That wouldn't matter as long as both the client and server are ticking this function.

[dry pebble]

good idea I'll try that

[dry pebble]

No CMC

[woven basin]

But I agree with Silex, it doesn’t make sense it’s “slow” on 0 ping. Sounds like you have a seperate issue…

[hollow eagle]

Also, you will run into some corrections happening just due to the server and client being slightly off at all times (even without network sim, they'd still be at least a frame off from each other). Which may result in a correction every network tick but it shouldn't be by much.

There's a general solution for that but figure out why it's such a big difference first.

[woven basin]

It’s almost like maybe the client or server is doing the calc twice? I.e. missing an Auth check somewhere?

[dry pebble]

I didn't have an auth check, just run on client and server as is

[hollow eagle]

This should be fine

[woven basin]

Maybe follow the paths and double check it’s only running where you expect? Just spit balling as well.

[dry pebble]

I'll do some tests ^^.

[austere burrow]

Again, sanity checking: marking properties as Replicated in a GameMode is meaningless, right?

holy moly the official epic tutorials introduce so much unnecessary confusion

[hollow eagle]

Which tutorial is talking about replicating properties in a gamemode?

[austere burrow]

https://www.youtube.com/watch?v=abmzWUWxy1U&list=PLZlv_N0_O1gYqSlbGQVKsRg6fpxWndZqZ

[quasi tide]

Which video specifically?

[neon mango]

What time stamp?

[quasi tide]

That's the entire playlist

[austere burrow]

Almost everything in LobbyGameMode he marks replicated, properties and events

[hollow eagle]

Oh

Welp

[austere burrow]

...yeah all the videos lol

[hollow eagle]

oh man you weren't kidding

they're using a switch has authority in the GM

yeah uh... wat

[quasi tide]

Can you timestamp link that?

[hollow eagle]

https://youtu.be/D6QtvPrqNLg?list=PLZlv_N0_O1gYqSlbGQVKsRg6fpxWndZqZ&t=222

gamemode exists only on the server. Checking authority is entirely pointless.

[quasi tide]

Mother of jeebus

[woven basin]

Man - can we ping someone at Epic; that should be removed. There is so much good content out there, having this is actually a negative.

[hollow eagle]

This stuff is also pretty old

I hope they put a bit more effort into keeping things on the new(ish) dev site up to date.

[quasi tide]

Oh yeah, super old.

[neon mango]

There is one comment on youtube from 2 years ago that mentions that

Did game mode ever replicate?

[hollow eagle]

Nope

[dry pebble]

@hollow eagle @woven basin Okay so well... it magically started working. Even with 500 ping, it's not that far off each other. I perhaps had some logic broken that with jump/dash cost that made the split so different lol. I'm glad you guys encouraged me to test it again, now I don't need to replicate stamina. I just correct it whenever there's a net correction now

[hollow eagle]

GM has always been server-only

it's the whole point of having a GM separate from game state

[woven basin]

Yay!!! I look forward to the final blog now 😂

[proud star]

i am looking to find out how to make player lobbies that fill up to about 15 players the enter a game level instance. part of what im trying to find out is how many instances of the lobby and levels would run simultaneously. does anyone know a good place for me to find some of this out?

[neon mango]

What do you mean by not replicating and only updating it where there is a "Net correction" ?

[woven basin]

Only way to know how many it can run is spin up multiple and test yourself. Each game is different.

[dry pebble]

So the client and the server both run the CMC. They both drain/regen a Stamina float on the CMC. And as @thin stratus taught me, I simply sync the client and server Stamina if there's a net correction.

[neon mango]

What calls the net correction? Is that a native engine thing? @dry pebble ?

[hollow eagle]

They're talking about replicating something for their character. Clients generally need to predict what the server is going to do for characters they control, but the server has ultimate say on what's actually going to happen. When the server and client disagree and the server tells the client to change a result that's a "net correction" (not a technical term for something in the engine, just generally what you might call it)

Client says some value is 10, server says some value is 20. Client corrects its value to 20.

[neon mango]

So stamina is getting replicated, but if its ever off, the server will correct it?

[hollow eagle]

Right.

[neon mango]

ok

thanks

was confused for a second by the it not being replicated part of the statement

[hollow eagle]

I think they just mean that the stamina value itself isn't being replicated directly anymore - instead they're sending a "set stamina to x value" rpc manually or bundling it with other data.

There are a few reasons to do that - primarily when you want direct control over how a client resolves incoming new data from the server.

Or if you only want to send a value at specific points in time rather than whenever it changes.

[neon mango]

Yeah I was hitting that point myself. Do I use an RPC or do I use a OnRepNotify and have the variable be replicated, not sure when to do what exactly yet

I think the end result will be the same either way

[hollow eagle]

Sort of

[dry pebble]

This is how I handle updating a custom stamina float and syncing it with the server when there's a correction. Whenever a correction happens, velocity/position etc gets synced, and we add our own custom float to sync as well like this. I could maybe check if the client and server stamina are far apart and sync another time too, but this is all I have for now.

void FMMOCharacterMoveResponseDataContainer::ServerFillResponseData(
    const UCharacterMovementComponent& CharacterMovement, const FClientAdjustment& PendingAdjustment)
{
    Super::ServerFillResponseData(CharacterMovement, PendingAdjustment);
    
    const UMMOCharacterMovementComponent* MMOMoveComp = Cast<UMMOCharacterMovementComponent>(&CharacterMovement);
    const AMMOCharacter* MMOCharacter = Cast<AMMOCharacter>(MMOMoveComp->GetCharacterOwner());

    Stamina = MMOMoveComp->GetStamina();
}

bool FMMOCharacterMoveResponseDataContainer::Serialize(UCharacterMovementComponent& CharacterMovement, FArchive& Ar,
    UPackageMap* PackageMap)
{
    //return Super::Serialize(CharacterMovement, Ar, PackageMap);
    if (!Super::Serialize(CharacterMovement, Ar, PackageMap))
    {
        return false;
    }

    if (IsCorrection())
    {
        Ar << Stamina;
    }

    return !Ar.IsError();
}


void UMMOCharacterMovementComponent::ClientHandleMoveResponse(const FCharacterMoveResponseDataContainer& MoveResponse)
{

    Super::ClientHandleMoveResponse(MoveResponse);

    if (!MoveResponse.IsGoodMove())
    {
        const FMMOCharacterMoveResponseDataContainer& MMOMoveResponse = static_cast<const FMMOCharacterMoveResponseDataContainer&>(MoveResponse);
        /*trust server and update stamina*/
        Stamina = MMOMoveResponse.Stamina;
    }
    
}```

[hollow eagle]

If you're just getting started with replication then go for whatever seems simplest to use for your situation.

And while it may seem like the result is the same either way, that's not quite true. Replicated variables only replicate at a specific rate. RPCs can get sent immediately.

And if you don't replicate a property then new clients joining won't have their value immediately.

[neon mango]

Are there any docs on CMC in general? Or just have to go through source and figure it out? Like what is ClientHandleMoveReponse for, is it just to handle Client Side Prediction ?

[hollow eagle]

Unfortunately CMC is its own documentation

as in no, there aren't really any good docs. Except one article that I can try to find...

https://docs.unrealengine.com/4.26/en-US/InteractiveExperiences/Networking/CharacterMovementComponent/

this is a very general overview and doesn't go into specifics about how CMC actually works or what various methods are for.

[dry pebble]

No, we're not replicating it. But will correct it during a correction (could be caused by them being too far out of sync for e.g or something else)

[neon mango]

I see, that saves on bandwidth?

I've just recently done a MultiCast RPC that also sets a Replicated bool, that is probably a bit redundant eh? I should just remove the replication from the bool in that case.

[dry pebble]

Yes, exe was saying it's not necessary to replicate it. They say "There is no need for it
The idea of the CMC is that it does the same on the server as on the client
In the same timestamp at least
If you consume the value during the sprint, it should consume on both ends the same
If you end up having a different value, it will cause a correction, at which point you send the server's value to the client to sync again"

[neon mango]

makes sense

[hollow eagle]

Replication on CMC specifically is a bad idea due to CMC handling conflicting results on client/server itself. It doesn't just stomp what the client sees with the server's result, it tries to smooth things over so you don't rubber-band a character.

[tranquil swallow]

Hey guys just wondering how I might do this.
Player A creates a session and can go mess around picking up item.

Player B joins the session after the player A picks up the item.

How can I sync everything up when player B joins?

[neon mango]

Well that's good for movement type stuff right?

[hollow eagle]

Replication outright stomps the client's value with the server's so you don't get an opportunity to resolve things "nicely" without some extra work.
In CMC's case, that extra work is very complicated.

[hollow eagle]

What CMC does, yes.

[neon mango]

Something like Stamina is better off on PlayreState or Player Pawn?

[hollow eagle]

Given that it affects movement, not necessarily

[quasi tide]

Seeing siliex take a more active role in #multiplayer is cool.

[hollow eagle]

I pop in here from time to time

[quasi tide]

You do - but it has been a bit more frequent the past few weeks.

[dry pebble]

Yus! it seems to work too. So this is how we handle stamina on the CMC instead of using a GAS attribute. Because those two don't like talking to eachother much lol

Although I did turn a "NotEnoughStamina" tag on whenever our CMC stamina is too low for a GAS dash ability and that works well

[hollow eagle]

Ideally anything movement related works through CMC because CMC has a whole framework for how clients can predict actions and how to apply corrections from the server.

Mirroring data to GAS isn't uncommon.

[fathom aspen]

That sounds like you missed the class on stateful replication: https://vorixo.github.io/devtricks/stateful-events-multiplayer/

[tranquil swallow]

Ill take a look at that

Also is there any better way of doing this or am I just dumb.

[fathom aspen]

Yes, there is, it's explained in the article

[dry pebble]

oh cool 'cause that worked well. perhaps it's more GAS -> CMC that isn't friendly lol

[neon mango]

Is the https://cedric-neukirchen.net/Downloads/Compendium/UE4_Network_Compendium_by_Cedric_eXi_Neukirchen.pdf still not pinned here?

[hollow eagle]

it is

[hollow eagle]

I think the general solution to that is to just use GAS to drive CMC actions on the client

[neon mango]

GAS meaning?

[hollow eagle]

but yeah, if you need something that depends on both GAS and CMC... that's a bit difficult

[fathom aspen]

Depends what that is, but a multicast for displaying effects is good (for spawning muzzle flash for example)

[dry pebble]

But if there's a net correction because of GAS, then the CMC correction would be all out of whack wouldn't it?

[hollow eagle]

Right

[tranquil swallow]

holy crap aint no way in the 2ms of me being in this chat you just gave really great info. ill read into it and if i cant figure it out ill post another thing. thanks

[fathom aspen]

The article I linked goes over stateful changes, for example a player changing his skin (which is what you asked for in the first place)

[iron crest]

Hello, I have a problem, im trying to open a widget depending on if I interacted with a bp character, problem is the widget never creates, I used some code for another actor that uses an interface, and iot still didnt work, any clue whats going on?

[dry pebble]

@woven basin I wrote some explanations and showed some code, lemme know if you need more 😄

[tranquil swallow]

From a while ago right?

[fathom aspen]

The article? It's a few months old

Younger than the outdated UE docs

[tranquil swallow]

I mean the changing skin thing. I dont think I posted anything in multiplayer about that in a while

[sinful tree]

You can't call Run On Server RPC on actors that are not owned by the client. This bit here wouldn't work assuming that the QuestGiver_Water isn't a player's character.

[fathom aspen]

This is what I meant with "in the first place"

That's a stateful change you're seeking to sync

[iron crest]

OK, Ill fix that part up and tes it

[tranquil swallow]

I mean the thing I was asking about was if a player picks up an item for instance a gun (which is spawned with the map) and then someone else joins later, I want to show the gun being held by the player and not still be on the ground

[fathom aspen]

I know, the article goes over how you achieve that

With another example

You should learn the technique and apply it in your own world

[iron crest]

Ok it still didnt seem to work, so I added a print string and just found out, that for some reason, the Event is never called

[fathom aspen]

Gameplay Ability System

Has its own channel too #gameplay-ability-system

[tranquil swallow]

I understand that but I'm not sure how I can make my whole system synced using booleans.

This is how my system works.

Gamemode Generates map based off a seed given in my online game instance

Roads are generated with that seed

Buildings which are childrens of a parent are generated around eachother

In each building child I have a empty with the location of the gun spawner empty

In the building child, when it is created it then spawns a random gun actor that I have.

Everything is the same but when the player joins, the map gets generated based of the seed in the players eyes including the guns. So not including any changes that happened before.

[fathom aspen]

OnRep the seed, and inside the OnRep_Seed you do what you want late-joiners (as well current clients) to see

Literally the same concept in that article

But I ruined the reading experience for you 😔

[tranquil swallow]

It's not though

In the article the example is if a player has press E and set the skeletal mesh while this has different steps, like if the weapon location, if it's attached to someone, who it's attached to, and just a few other things

I just had a big brain idea, one moment I am gonna just look up smth rq

[bronze mauve]

Why do you feel like you must generate the level client-side when it's already being constructed server side?

Like why not just generate the level with all replicated actors

[fathom aspen]

It's, it's just that you're not able to connect the dots tbh. Replicate the effing variable the way you see best and just let the OnRep do its thing

[hollow eagle]

@fathom aspen did you mean to link this article instead of the one you did earlier https://vorixo.github.io/devtricks/procgen/

because that seems more relevant

and it does go over this specific stuff

[fathom aspen]

Oh yeah that could be tbh, I just skimmed through it last time, so could be

[bronze mauve]

Like the client would just join the session and the level would already be there all made already

[hollow eagle]

this is the one about local generation + net addressability

[hollow eagle]

so yeah, @tranquil swallow ^

[bronze mauve]

Also if OnRep is called before the client joins they won't ever get it

[hollow eagle]

replicated values will be sent on initial join regardless of when they changed, provided they don't have a condition against it

are you thinking of an RPC?

[tranquil swallow]

Thanks, Ill take more of a look into it

Sorry my pea brain just cant comprehend multiplayer lol

[bronze mauve]

So a replicated variable that changes 10x on the server before a client joins... the client will join and automatically have OnRep fired off with the most recent value??

[fathom aspen]

Yeah the seed now make more sense for them to look at that article, though they will find some advanced bits of info if they are BP-only beeps 🥲

[fathom aspen]

Incorrect

[hollow eagle]

yeah sadly that article isn't relevant for BP only because epic pls

[hollow eagle]

the client will have the latest value set, yes

once the actor replicates at least - which may take some time.

[fathom aspen]

OnRep is per client, so the client gets it when they log in and they get synced by the server @bronze mauve

[bronze mauve]

No way, I didn't know that

So yeah, OnRep_Seed seems like it would do it then.

[quasi tide]

It would be kind of silly for the client to not get the latest value when OnRep is meant for stateful changes

[bronze mauve]

You're referring to the single trip time?

[hollow eagle]

When a client joins it takes time for the initial replication of actors. Which happens in an effectively random order over multiple frames based on network conditions.

[bronze mauve]

I wasn't insinuating that it would get a less-recent value, rather mistakenly assuming that it wouldn't get any replicated value at all that came in before the client joined the session

[hollow eagle]

but BeginPlay won't be called on replicated actors until their own replication has completed, which includes the latest replicated properties from the server.

BeginPlay will however be called on replicated actors as soon as they are ready, even if other replicated actors aren't. Which goes back to how the order of actor replication is random.

[fathom aspen]

By basically PostNetInit calling BeginPlay

[bronze mauve]

Yeah it seems their BeginPlay gets called sometimes before said actor's player state/player controller etc. Are assigned/replicated sometimes

[hollow eagle]

Exactly

You can't depend on replication order, sadly. "Important" actors like game state might not be ready when other actors are.

So unfortunately a common pattern is to delay your initialization until everything you care about is ready.

Kind of a pain tbh.

[fathom aspen]

AFAIK it must if it's being accessed from BeginPlay of actor (yes it's mind-blowing)

[bronze mauve]

How do you get around this problem? Like say you want to do something important like initialize a HUD. But you can't do it in BeginPlay because the info you need exists on some other class that might not have replicated yet

[hollow eagle]

Ah you might be right about game state specifically since it routes beginplay

but other actors, nope

player state and such

[fathom aspen]

Exactly, it's what "initiates" BeginPlay on clients worlds

[quasi tide]

I handle HUD stuff in OnRep mostly.

[fathom aspen]

Fought Zlo a couple of times over that but yeah it is what it is

[hollow eagle]

So a lot of player-related actors won't even get created until you have a valid player controller and such so it isn't an issue.

[bronze mauve]

Like delay node: 2 seconds or something? Idk it seems hacky and prone to errors due to the unreliability of speeds

[hollow eagle]

The issue is really around depending on other "global" things that might not be replicated yet.

[quasi tide]

lol - a losing battle I bet

[fathom aspen]

Exactly that's why the guarantee becomes useless

[fathom aspen]

99% of the times yes

[hollow eagle]

Nope, because that 2 seconds might not be long enough on a bad connection.

[fathom aspen]

I only won one time, when I said Push Model can be used with no cpp lol

[quasi tide]

A victory is a victory

[hollow eagle]

If there are a set of common actors you absolutely need to be ready before running your initialization logic, you might write a "global" system that exists clientside that checks every frame if everything you care about is ready, and then fire off initialization from there.

This is a bit easier to handle in C++ than Blueprint

Even better, don't check every frame and just have those important actors tell the system when things are ready.

[bronze mauve]

Ahh checking each frame, the "polling" method then

Ah okay so like a single manager class that knows when things are ready and relays that to each relevant class

[hollow eagle]

Yep, that'd be a decent way to do it.

[bronze mauve]

Like it has handles on the PlayerState, PlayerController, HUD etc. Also though it kinda needs to know about client and server side too doesn't it

[hollow eagle]

On the C++ side I've very often written methods like this:

void CallOrRegister_OnInitialization(FSomeDelegate Callback);

Which calls the given callback immediately if everything is already ready for initialization, or stores the callback for later if things aren't ready.

[bronze mauve]

I like this

[hollow eagle]

I think Lyra uses that pattern in a few places

[bronze mauve]

It's like fire off now if ready, otherwise just fire me off when you're ready

[hollow eagle]

Yep

[bronze mauve]

Yeah Lyra has a bunch of "Register this, register that" all over the place

[fathom aspen]

There is such a subsystem James and vori made but I'm not able to find it

Okay found it https://vorixo.github.io/devtricks/non-destructive-synced-net-clock/#the-problem-with-synced-network-clocks-in-general

https://cdn.discordapp.com/attachments/221799385611239424/992481326093574155/NetworkEventSubsystem.zip

[quasi tide]

Speaking of James - he must be on vacation 😅

[hollow eagle]

ah nice

[fathom aspen]

Yeah hasn't showed in a while

[bronze mauve]

Um, should I know what paliate means?

[hollow eagle]

tbh I haven't had a need for that kind of thing on clients. I have on the server though - waiting for players to finish joining before initializing a match.

[bronze mauve]

It's an interesting article though haha

[quasi tide]

Reduce the pain of the situation pretty much

[hollow eagle]

Actually I take this back - I needed it for one specific thing... waiting for a bunch of subobjects to replicate ;_;

why does subobject replication suck so much

iris save us pls

[fathom aspen]

Epic fixed it for you in 5.1, next

[bronze mauve]

Does anyone know anything about iris yet? Is it in UE5 yet?

[quasi tide]

It's in UE5, yeah.

[fathom aspen]

Our lord and savior

[quasi tide]

Some of the smart people say that it does look nice. But that's about the gist of it.

[bronze mauve]

In toto?

[hollow eagle]

actually the biggest bug I hit with subobject replication was that a random object I had was marked as RF_WasLoaded (which prevents full replication since it's loaded from disk). But DuplicateObject doesn't strip that flag by default for some reason ???

[bronze mauve]

Are there any such smart people who have created any guides for us yet lol

[hollow eagle]

So I passed a duplicated version of it without knowing it wouldn't replicate

[quasi tide]

There isn't anything worth to make a guide on

Iris is still super new

[austere burrow]

Is there a way to get the previous value from a RepNotify in BP? or only CPP?

[quasi tide]

Only in C++

[tranquil swallow]

Question. When a gamemode has a event that is ran on the server on beginplay, would that run everytime someone joins or just once

[fathom aspen]

I like those low level bugs/issues

[bronze mauve]

As in there isn't much code to look at? (I obviously haven't looked at it)

[quasi tide]

As in, it's not really usable.

[hollow eagle]

As in no one knows enough about it yet.

[austere burrow]

sad but thanks

[hollow eagle]

It's experimental and there's no documentation.

And brand new.

[bronze mauve]

So it's pointless to even look at this point lol

[hollow eagle]

Pretty much

[quasi tide]

Just once. GameMode is an actor. BeginPlay only fires once for it.

[tranquil swallow]

So if someone joins later after that gamemode as been ran, it will not rerun

[fathom aspen]

Just once, as there is only one server instance

[quasi tide]

Definitely not. GameMode already exists when a new player joins.

[tranquil swallow]

Gotcha. Thanks, just tryna work through which stuff is replicated and how I can make this not as shitty

[quasi tide]

Well - nothing in GameMode is replicated. So that solves that problem for you.

[tranquil swallow]

I spawn actors that are replicated, would that be a issue

like performance wise

[quasi tide]

Not enough information

It can be. Sure.

[tranquil swallow]

fair point lol

one sec let me word it out

I have a gamemode that spawns quite a bit of building actors which have replication enabled, this allows me to see all the buildings.

Would it be better to have an actor that the gamemode spawns which spawns the map (and only have that replicated)

not sure if that would work but yeah

thats what i'm kinda trying to say

[quasi tide]

GameMode can spawn things that are replicated themselves, yes.

Spawning an actor that is a replicated actor is perfectly fine.

[tranquil swallow]

Ok so it wouldnt be bad to do it the way I'm currently doing it

[quasi tide]

I don't know if I'd use the GM to spawn building actors personally

[tranquil swallow]

How would you do it just generally

[hollow eagle]

You can use whatever you want to spawn replicated actors

What spawns it doesn't really affect anything about replication

[fathom aspen]

It becomes a design matter

[hollow eagle]

If an actor is replicated and exists when a client joins, it'll be replicated.

[tranquil swallow]

Wouldnt having a map generation in a gamemode be better because gamemodes are ran when the session becomes a thing

[fathom aspen]

#just-adore-replication

[hollow eagle]

that's not what gamemodes are

gamemode has nothing to do with sessions

[tranquil swallow]

I think I used the word wrong

[hollow eagle]

the gamemode is created upon loading into a level as part of initialization of the world

but so are all other actors in the level

[tranquil swallow]

I meant the world

[hollow eagle]

if you want the gamemode to create your actors, then you can do that just fine

[fathom aspen]

If you looked at the article siliex linked you would see that's more or less what is done there

Well they have a dedicated actor it seems ProcGenSpawner

But it's managed by GameMode

[bronze mauve]

Keep in mind the GameMode itself is null on clients

Not that they can't spawn replicated actors. Just saying

But a proc Gen level spawned seems like it should be handled by its own class dontcha think?

[fathom aspen]

That's a design question, but if you're asking about my opinion nah, I find the GameMode pretty handy for spawning it

Like it spawns/manages other replicated actors already

GameState, Pawn, etc.

[hollow eagle]

The benefit of the gamemode not being what handles it is the process can be initiated on the client separately (and then link generated actors up to the networked ones). Which can save on bandwidth and initial replication time, but for a beginner this is super unnecessary (and not possible in pure BP).

[fathom aspen]

Yeah I figured a bit later that they static load the PrcGenActor

[quasi tide]

@fathom aspen 😅

[fathom aspen]

Yes that's the new travel, it happens so fast, that why it's seemless

[quasi tide]

Travel go brrrr

[fathom aspen]

Wait is that in my website?

Or docs?

[quasi tide]

No - the documentation for UWorld::ServerTravel()

[fathom aspen]

Noted, thanks!
I already have plenty of them heh

[quasi tide]

@fathom aspen You might get a kick out of this: #cpp message

[wooden plover]

Trying to keep things free. It should be possible to learn all this information for free

[prisma snow]

I'd use the compendiums pinned in this channel, they're excellent

[pallid mesa]

Ahh duplicate object is its own can of worms XD

[wooden plover]

@sinful tree Got it 🙂 Thanks for your help!

[obsidian basin]

Ok, Im stumped. Can anyone offer a concrete solution on how to verify a clicked actor on the server? I've been trying to do the math of a line trace for a few hours, but I'm stuck and I think I might be doing it incorrectly.

[fathom aspen]

This seems like deprecated since release... jeeez

[prisma snow]

What is the context? If the click is for "UI" purposes (for example, selecting the actor) I'd do that entirely client-side

[obsidian basin]

Gameplay. Think of old school MMOs where you select someone or a mob and then just auto-attack them.

To clarify further, I'm using Get Hit Result Under Cursor For Objects right now

Which is great local, of course but not so great for server replication and verification

[prisma snow]

Mmm but I don't get the purpose of making it server-side. For example, in an FPS it makes sense to check server-side if the client did aim correctly a shot, because it could happen that the enemy is not there.

However, in this context, is the 'aiming' part that important? It sounds like it is akin to selecting a unit in an RTS game, just a client-side way to interface with a entity

[prisma snow]

Have you tried to do it client-side first to see if the problem is due to the server or it's something else?

[obsidian basin]

The main reason is I'm concerned about cheating. Since you have to select a player or a mob to fight them, I'm worried the client could say it's selected a mob that's nowhere near them and then fight them.

I did plan some additional behaviour, like upon starting an attack you have to move into range to actually hit it... maybe that would mitigate any concerns I have and I'm just inventing problems that aren't present.

It works client side (I store it to Player State as I want other players to see what players are targetting), but again - concerned about how secure it might be.

[prisma snow]

The server should check the conditions that are relevant to gameplay. For example, if the target is in range, if the player has enough mana, damage and health calculations...

The fact that the player cheats to select an enemy does not sound like important at all, it's not like an aimbot or smth

[obsidian basin]

Yeah I think you might be right. I guess if I had an ability that auto-hit something with no range it would be an issue if I cared for LOS, etc.

But I don't plan to have anything like that. any sort of attack will need to be within X meters and have los, so those I can always easily check on the server

[prisma snow]

yeah, exactly. Basically, anything that is really dependant on aim or exact location might be worth checking on server.

just make sure to check everything important (mana, range, that kind of conditions) so that players cannot cheat there

[obsidian basin]

Yeah, luckily those are much easier to check. Thanks for being a sounding board!

[prisma snow]

np, glad to help and be useful

[verbal tendon]

The most maintainable way to do this is to have a function for the condition check

that you call on both client and server

instead of separately maintaining all checks in two places

@obsidian basin

[real ridge]

Hello guys I have weird problem I propably made some dumb mistake I have healthbar on my plane and when I am shooting I am applying damage on his health but as you can see on the screens it is replicating damage for both of players on the left window but on the right both have full health what can be problem?, this is how I am doing it I am using repnotify

last screen is from widget health bar

[verbal tendon]

GetPlayerPawn(0) is your problem

Most likely without seeing more

Or GetPlayerController(0) - the screenshot is limited, there's not enough context, but you want to avoid those in general

There's more issues I have with the screenshots, you're updating UI on EventTick, rather than only updating it when the value changes

[digital marten]

I'm using a pawn as my player character because I'm doing spaceships demo. Clients are spawning as Authority not Simulated Proxy. How do I change this?

[verbal tendon]

Also if one of those windows is the ListenServer, you don't get a repnotify there, so your 2nd value is never set

Which is another problem, don't have multiple places that represent the value that you then update arbitrarily

Use delegates, keep the value in one place, don't copy it everywhere, the other places that do read from it, should change their display or usage when the value changes in the place that has ownership over it

[real ridge]

how then update value when it changes like health if no on event tick

[real ridge]

now I changed it to this , first photo is after linetrace when I hit pawn I will send whom I hit, second photo is when i get hit as pawn I will take a damage and third photo is bind action made for my progress bar

but it seems it has same result

[verbal tendon]

you haven't changed any of the core logic, just moved things around

all of my previous messages still apply, it's most likely one of the two outlined problems

[real ridge]

i am not using repnotify now but I need use get player pawn when I need cast to pawn to get health

[verbal tendon]

Im not gonna be available until in about an hour. are you using two clients, paly as client, or one listenerver and one client?

[real ridge]

2clients

[agile loom]

Server should spawn them

[digital marten]

No clue what's going on. I just tried making them based on character, not pawn and it works, but I get the same authority message 🤷‍♂️

[agile loom]

Game mode spawns the pawn?

[digital marten]

It does spawn the spaceship pawn.

[agile loom]

The local role is authority? or the remote role?

[agile loom]

And the pawn is set to replicate and only spawned by the server?

[digital marten]

I did some digging in C++ and Character has code for serializing movement and movement prediction - CharacterMovementReplication.h.

Pawn doesn't have any serialization code or movement prediction....

That's probably related to my problems...

[verbal tendon]

So as always with MP logic you need to do debug. It's possible that you are calling your Server_ApplyDamage function from a non-owned actor

And then it only executes locally

So for Client1 for example

[real ridge]

I already solved it

[verbal tendon]

and you are still getting player at index(0) for your health bars

instead the healthbars should know what actor they are a part of

and get that actor's health

[real ridge]

I got reference for my widget and then press set percent

set percent

then did update hud

and multicast it

and its working

[real ridge]

yes this helped me thanks

[verbal tendon]

So that's the problem with only showing small snippets, you have cutoff functions

so it didnt show that you're not multicasting it from the AnyDamage event

Always provide as much context as possible, then it's easiest to get help

[real ridge]

I know but when screen is big everything is small and you cant see it

😄

[verbal tendon]

you've taken small cropped screenshots, those can be larger to include everything in the function

the person helping will click on the image to get the full resolution on discord

The smaller resolution version in text is just downsized, but the full-sized version is available

[real ridge]

✅

now I need to solve my bigger problem 😄

[verbal tendon]

🙂

baby steps 🙂

[real ridge]

yea 🙂

I do have function update position in my plane which is doing exactly moving in the air for my plane but when I try replicate it after Event tick (because I need move him every second) doing it like this , I am replicating it but with very stranges differences I made screen with numbers of planes plane 1 and plane 2 they are in different positions on both windows Idk what can cause it

also getting this error related to calling fly server from event tick

[raven tangle]

Trying to make a homing projectile work for the first time. It replicates its movement but not rotation (client on the right side). Any idea what did I forget?

[verbal tendon]

It's been years since I last looked at this, the rotations aren't all replicated

You gotta use the right rotation and not the one that is local only 😄

Ofc depends on how you implemented the projectile and what rotation it is using

[raven tangle]

It is a homing projectile, so it sets it rotation to the target automatically it seems

At least on the server

[verbal tendon]

Think of it this way, always look for things to reduce being replicated

this looks like it can simply be simulated on the client

[raven tangle]

Indeed, that's a good idea. Thanks!

[verbal tendon]

It's rotation has no impact on gameplay, it's purely visual

[raven tangle]

Thought the projectile movement component would do that for me 😅

[verbal tendon]

All epic classes are designed for some standard usage, if you want to do something special you need to take care of it yourself

the PMC's designed for easy to use projectiles. It'll take care of rotation based on movement if you let it, if you want your own arching rotation and whatnot, you gotta implement them things yourself

[jolly delta]

is there a node to check if the client is well connected to the server ?

[dry pebble]

So I figured out my stamina regen issue, but not sure why it happens. When sprinting and then letting go of input to stand still, server and client regenerate stamina aa similar speed. But when I press "shift" to cancel sprint and then idle, the client regenerates 2x faster than the server. The only difference being DeltaSeconds. This is the code

        else if (!IsSprinting() && Stamina < MaxStamina)
        {
            StaminaRegen = 3.f * DeltaSeconds;
            SetStamina(StaminaRegen);    
        }```

The StaminaRegen difference

Pressing shift:
StaminaRegen = 3.f * DeltaSeconds;
0.06 0.03 client 2x faster
0.18 0.08 client 2.25x faster
0.26 0.13 2x faster
0.38 0.18 2.1x faster
0.45 0.29 1.5x faster
0.5 0.29 1.7x faster

Letting go on input
0.023 0.024 - same for 3 frames
0.033 0.024 1.3x faster
0.024 0.24 - same for 5 frames
0.024 0.03 0.8x faster
0.025 0.024 - same for many frames
0.024 0.024

Any idea why pressing input to cancel a sprint (compressed flag) would somehow change the deltaseconds?

[neon mango]

Are you checking Delta Seconds to see that the difference in Delta Seconds is enough to cause a 2x difference?

Maybe SetStaminaRegen is getting called twice on Client

[tired mason]

I could be wrong, but I think what is actually happening is that it's double stacking the input of shift somehow. It seems very unlikely that it's changing delta timings

[tired mason]

This

[dry pebble]

Oh interesting... how do you think I could prove/breakpoint that?

[tired mason]

Do once node I believe would be the solution to prevent it from running more than once on a single input, and print string just to see how many times it actually fires the event

Pretty sure this is the issue though, as I had the same issue with a sprint system at one point and it sounds very familiar lol

[neon mango]

If the var were replicated then the client would have it be corrected to servers

[dry pebble]

Perfect I'll try that

[dry pebble]

yeah it's not replicated, only syncs up with a net correction.

[neon mango]

If not replicated you would want to be sure there is some error checking then right?

[dry pebble]

it's still server auth

[tired mason]

Let me know if that works or not, at the Dr's office ATM bored

[neon mango]

If it were server auth then Client wouldn't get double the regen speed on server?

[dry pebble]

it's server auth with what it does with the stamina. E.g client at 90 stam, server at 40 and if client tried to jump (need 50 stamina), client will have a net correction, server won't allow it.

[dry pebble]

will do 😄

[neon mango]

oh so just a visual issue won't actually effect gameplay

[dry pebble]

they're mostly always in sync + or minus a bit even with 500 ping, so this other issue is some weird thing

[jolly delta]

level blueprint depend of the server right ? client has no authority on it?

[tired mason]

Correct

[jolly delta]

so i can consider that as a gamemode ?

[neon mango]

No

Because game mode can be set on any level

and level BP is just for that level

[jolly delta]

yeah i know

i mean reagarding network

[neon mango]

Not sure I understand?

[jolly delta]

is the starting new player is call on every client in addition of the server ?

[dry pebble]

you're right, client is calling it twice!

[tired mason]

Nice! Well now you know

[dry pebble]

Why the hell would it call it twice by pressing input again if anyone knows? It's a compressed flag in the CMC to toggle sprint on and off

[dry pebble]

Do you know how to call DoOnce in C++?

[tired mason]

Ahhhh, I'm pretty new to c++ still, not sure. Let me do some googling

[agile loom]

Use a bool
bool DoOnce = true;

[tired mason]

Oh? It's actually that simple? I found some examples that weren't that simple 😅

[dry pebble]

ahh yes, it seems that's it lol. Lemme try it

[tired mason]

Here's one I found. I'd certainly use the simple method over this

[neon mango]

You mean Player Login? That only happens on the server in the Game Mode

[agile loom]

in header
bool DoOnce = true;
and in .cpp

    if (DoOnce == true)
    {
        DoOnce = false;
        // Do something
    }

[jolly delta]

so why if I print something is it printed on everygame ??

[neon mango]

IDK what you are printing, where you are calling it to print and how you are testing.

[jolly delta]

i run a server with a command and the client standalone trough the editor

[neon mango]

@dry pebble I don't think Do Once is the right solution, it is likely a Band-Aid to the real problem.

Having more "regen" type variables to manage and having a bool just to do them once doesn't seem scalable

[neon mango]

Can you show me the prints?

[dry pebble]

Yeah defs a bandaid. Couldn't get it to work anyway lol, as by resetting the bool back to false runs it again anyway.

I'll scour through the discord and see if anyone else had this weird input double method issue

[neon mango]

What are you replicating? Maybe you need to do a check so that the call only happens server side? Are you doing Server only RPC, a MultiCast?

But if its a sprint type thing you are wanting the client to do it locally so it looks proper ?

So client does it once locally but is server telling client to do it again?

[dry pebble]

I'm not replicating the stamina right now (that's a last resort). So client and server are both running stamina drain and regen, but server is still authoritative. The stamina for the client is for UI

[tired mason]

Ah sorry about that. I'll take a look at my code base later when I'm home and see how I fixed this issue. Can't remember the actual fix off the top of my head

[dry pebble]

UpdateCharacterStateBeforeMovement
        if (IsSprinting())
        {

            const float SprintStaminaDrain = Velocity.Size() * StaminaDrainFactor;
            SetStamina(-SprintStaminaDrain);

        }        
        else if (!IsSprinting() && Stamina < MaxStamina)
        {

            StaminaRegen = 3.f * DeltaSeconds;
            SetStamina(StaminaRegen);

        }

void UMMOCharacterMovementComponent::SetStamina(float NewStamina)
{
    Stamina += NewStamina;
//For UI on client
    if (OnUpdateStamina.IsBound())
    {
        OnUpdateStamina.Broadcast(Stamina);
    }
    
}
    ```

[neon mango]

But its only a client side issue? Server doesn't have the issue right?

[dry pebble]

that would super helpful, thank you!

[dry pebble]

No issue on server, server calls the method once

[quasi tide]

@thin stratus Hey Cedric - a little bit ago you were going to try out the seamless travel in PIE thing added in 5.1, if you did, did it work? 😅

[neon mango]

Seamless travel in PIE?

[thin stratus]

No I haven't tried it. I only noticed the console variable.

[dry pebble]

If I let go of WASD keys, client and server regenerate at the same rate. It's only when toggling sprint manually and letting go of WASD (so idling) that client calls it twice.

[neon mango]

If none of that is replicated I'm not sure why there would be a difference between client and server like that

[dry pebble]

Yeah the only replicated part is the sprint flag (left shift)

[neon mango]

Are you checking the value of the sprint flag client side ?

[dry pebble]

Actually nvm IsSprinting() just checks if our speed is sprinting speed

bool UMMOCharacterMovementComponent::IsSprinting()
{
    return Velocity.SizeSquared() > pow(MaxWalkSpeed , 2) && (Acceleration.Size() >= (MaxSprintSpeed - 100.f));
}```

[thin stratus]

@dry pebble What are you struggling with

[verbal tendon]

This is not going to happen. There are various tech debt items inside of the engine source that prevent this.

So fixes to the engine would be in order and Epic would need to accept them

[neon mango]

@thin stratus Her client side sprint drains twice as fast as servers

[verbal tendon]

Also Epic keeps adding new tech debt to this with major releases, because it's not supported in PIE

[thin stratus]

They introduced a new console variable lately, so they are working on it

[verbal tendon]

I haven't seen that yet, I just noticed the new tech debt in 5.0 , that was the last time I checked

😂

[dry pebble]

When I'm sprinting, the stamins is drained. When I let go of WASD input to idle, client and server regenerate stamina at the same rate. But if I toggle "left shift" to stop sprinting, client regenerates double the speed as the server, it calls the stamina regeneration twice.

[latent heart]

You aren't somehow making stamina drain framerate dependent, are you?

[quasi tide]

#multiplayer message

[verbal tendon]

I'm also currently working 100h weeks atm, no luxury time for checking much right now. I haven't caught up on the 5.1 changes

[dry pebble]

this is the code, it regens with deltaseconds #multiplayer message

[thin stratus]

Where are you draining the stamina?

[dry pebble]

UpdateCharacterStateBeforeMovement in the CMC

[verbal tendon]

Very cool. That would be a great improvement. I'd love for PIE to be a first class citizen

also 3D UI being fixed in multi-session PIE would be great

[thin stratus]

How much FPS does your Client have

[latent heart]

Regen is with delta seconds, sure, but I responded to a message about drain. Also SetStamina is a bad name for a method that adds stamina.

[neon mango]

Doing some MP prototype work in 5.1 and Net Mode listen server with 2 clients has a 30 or so second lag and I have yet to figure out why. No server lag emulation on.

[dry pebble]

I'll check

[quasi tide]

ModifyStamina(float ModifyAmount); - fite me Daekesh ✊

[latent heart]

I'd go with that.

Or DeltaStamina maybe

[twilit radish]

-500 👀

[verbal tendon]

30 seconds ? 😂

or did you mean milliseconds? lol

[dry pebble]

capped to 120 it looks like, flickers between 119 to 120

[latent heart]

Also, just to make a point, the stamina drain does not appear to use DeltaSeconds at all. Unless you are hiding part of the method.

[thin stratus]

Can you cap it to 60

And tell me if it's still broken

[dry pebble]

kk

[thin stratus]

t.maxfps 60 or so

as a console command

[dry pebble]

Deltaseconds is passed in from the main method sorry

void UMMOCharacterMovementComponent::UpdateCharacterStateBeforeMovement(float DeltaSeconds)```

[latent heart]

So? It's not actually used in half of your code

[dry pebble]

omg you genius!!!! that fixed it!

[neon mango]

So the FPS were different between client and server?

[thin stratus]

Didn't I tell you that you need to implement the SavedMove for your Stamina

No

She's running into Combined Moves

If the Client has over 60 fps, it sends the Move Combined

[neon mango]

Ohhh

[thin stratus]

But it performs the move first, then combines it and then performs the combined one

Performing the original move twice

[latent heart]

Try setting it to 30 fps first, just to check.

[dry pebble]

I do with float Saved_Stamina; and in SetMoveFor and PrepMoveFor and Clear(). Is there somewhere else to add it?

[quasi tide]

Thank you for having dreams about the CMC Cedric.

[thin stratus]

Yes, CombineMove

You need to use the initial position or so function

Save your Stamina there

And in the CombineMove function

You gotta set the CMCs(!!) Stamina back to the Old Move

[neon mango]

Well that is illuminating

[quasi tide]

You know what - screw it, unlimited stamina. Easy.

[neon mango]

MP management what fun it is

[dry pebble]

ohhh oops. Lemme have a look and see if I can do that.

[thin stratus]

void FSavedMove_SomeCharacter::SetInitialPosition(ACharacter* Character)
{
    Super::SetInitialPosition(Character);

    const USomeCharacterMovementComponent* CharacterMovementComponent = Cast<USomeCharacterMovementComponent>(Character->GetCharacterMovement());
    if (IsValid(CharacterMovementComponent))
    {
        bSavedWantsToSprint = CharacterMovementComponent->WantsToSprint();
        Stamina = CharacterMovementComponent->GetStamina ();
    }
}

void FSavedMove_SomeCharacter::CombineWith(const FSavedMove_Character* OldMove, ACharacter* InCharacter, APlayerController* PC, const FVector& OldStartLocation)
{
    Super::CombineWith(OldMove, InCharacter, PC, OldStartLocation);

    const FSavedMove_SomeCharacter* OldVRTMove = static_cast<const FSavedMove_SomeCharacter*>(OldMove);

    USomeCharacterMovementComponent* CharacterMovementComponent = Cast<USomeCharacterMovementComponent>(InCharacter->GetCharacterMovement());
    if (IsValid(CharacterMovementComponent))
    {
        CharacterMovementComponent->Stamina = OldVRTMove->Stamina;
    }
}

[dry pebble]

omg thank you so much, I was getting confused again on how to get the old move. Gonna set it up now. Exe you're an absolute legend!

[twilit radish]

Cedric, when are you writing your own CMC as a plugin and publishing it? I can't imagine that being more difficult than constantly dealing with stuff like this 😛

[quasi tide]

Surely this will be in the network bible 2.0, right?

[neon mango]

I haven't messed with CMC for networking since UE 4.20 and remember absolutely nothing from the work I did there. Got something working and was happy lol

[dry pebble]

Oooh you're using CombineWith, thought it was CanCombineWith, no wonder I was confused lol

[thin stratus]

What the CMC does is:

// Frame n

1. Check if there is a PendingMove (let's assume there is not)
2. Perform the NewMove (let's call it MoveOne)
3. Perform MoveOne
4. Check if it should postpone sending the move (>60 fps by default will cause this)
5. Set PendingMove to MoveOne and don't send move

// Frame n+1

1. Check if there is a PendingMove (yes there is)
2. Check if we can combine PendingMove with NewMove (MoveTwo)
3. Let's assume we can combine it so combine them
4. Perform CombineMove
5. Send CombineMove

The point here is that Frame n and Frame n+1 both will Perform MoveOne. Just that Frame n+1 will do it due to it being Combined with MoveTwo

That's why Epic reverts everything requires back to BEFORE MoveOne inside of CombineMove

[rose egret]

where sever takes viewlocation of players from ?

[thin stratus]

So you gotta do that for your Stamina

[rose egret]

I want to check if there is any player near my actor on ded server

[thin stratus]

CanCombineWith is just the check before it combines

By default this will fail if the Move can't be combined

E.g. cause we are sprinting in this frame but not in the new one

Or other way round

You only want to combine moves that don't cause problems if combined and can act as one bigger move

If you hold forward the hold time, you can just move twice as far in one move

But if MoveTwo for example means that you start sprinting, then you want to ensure that doesn't get combined

That is checked via the Flags already though

I only check this stuff here which shouldn't be important for you

bool FSavedMove_VRTCharacter::CanCombineWith(const FSavedMovePtr& NewMove, ACharacter* InCharacter, float MaxDelta) const
{
    const bool bSuperCanCombineWith = Super::CanCombineWith(NewMove, InCharacter, MaxDelta);

    const FSavedMove_VRTCharacter* ThisVRTMove = static_cast<const FSavedMove_VRTCharacter*>(this);
    const FSavedMove_VRTCharacter* NewVRTMove = static_cast<const FSavedMove_VRTCharacter*>(NewMove.Get());
    
    if (ThisVRTMove->bBoostOnCooldown != NewVRTMove->bBoostOnCooldown)
    {
        return false;
    }

    if (ThisVRTMove->bCanBoostXY != NewVRTMove->bCanBoostXY)
    {
        return false;
    }

    if (ThisVRTMove->BoostCooldownTimestamp != NewVRTMove->BoostCooldownTimestamp)
    {
        return false;
    }
    
    return bSuperCanCombineWith;
}

[dry pebble]

Taking a moment to read your message to let it sync in, appreciate you writing it up!

[thin stratus]

I'm not using PrepMoveFor

Cause I don't need to prep anything when boosting/sprinting

[neon mango]

@thin stratus Would there be enough example code for Inputs like that if you look at source for "Jump/Jumping" and model that?

[thin stratus]

Jumping has no extra value

You will only find the Location being reset

in the parent implementation of CombineWith

Someone posted some info about the CMC ages ago

You can find that via google

But it's lacking

And not 100% correct

So I won't link that

[neon mango]

There was one blog I read back in 4.20 days that guided me and I can't find it, thought I bookmarked it

[obsidian basin]

So upside: I figured out how to spawn non-player controlled mobs. Downside my selection logic breaks clicking on them during the server call.

[latent heart]

Are you spawning them on the client?

[obsidian basin]

Gamemode is casting a Multicast event, so I don't think I am.

[thin stratus]

Ouch

GameMode doesn't exist on Clients. Multicast is not a thing that works in GameModes

You can just leave that a normal Event

[latent heart]

Well, it'll run on the server 😛

[thin stratus]

:pain:

[obsidian basin]

eer not game mode, game state

[thin stratus]

That on the other hand would be bad

[obsidian basin]

Sorry I just woke up

[thin stratus]

Cause you want to only spawn them on the Server

So you should still not set that to be a Multicast

[obsidian basin]

But Game Mode is a better place, or is there somewhere that's more desirable for this?

[thin stratus]

Doesn't necessarily matter at this point

As long as you don't spawn them via a Multicast

[quasi tide]

Just pick a place to spawn something and do it only on server.

I have a spawner actor that handles this for example.

Not necessarily GM or GS.

[obsidian basin]

Ah, smart

[quasi tide]

It is completely design dependent

Just make sure you only spawn most things on the server.

[latent heart]

You have an actor with functions? DawnMech will be mad! 😄

[quasi tide]

It even uses inheritance 🤫

[obsidian basin]

I heard there was a way to mark a placed object be server owned as well, is that true?

So if I wanted to move the logic for each spawner into the spawner actor itself.

Things like respawn time, type of mob to spawn, etc.

Or is the spawner, which calls the spawn function ont he server enough?

[quasi tide]

My spawners are on the server only.

[obsidian basin]

Ah, so placing a mob = no go. Placing a spawner which then spawns the mob on server = ok

[quasi tide]

Placing a mob is fine as well.

The server still owns that.

[latent heart]

Just don't spawn things on the client

[obsidian basin]

Got it

Thanks

[dry pebble]

So just to clarify I understand, Frame n+1 is setting Stamina twice because it is MoveOne + MoveTwo combined? And we don't actually want Frame n+1 to call MoveOne again on the client right? So to combat that, for Frame n+1, we reset our stamina back to before MoveOne in CombineMove. But MoveTwo still runs as usual?

[thin stratus]

And we don't actually want Frame n+1 to call MoveOne again on the client right?

That's not something you control

That's how the CMC works

[dry pebble]

Oh okay, so it's going to call it anyway, and we handle it with CombineWith?

[thin stratus]

So to combat that, for Frame n+1, we reset our stamina back to before MoveOne in CombineMove.
Correct

But MoveTwo still runs as usual?
No, MoveTo is now part of the Combined Move

MoveThree will be a single move again

That is later combined with MoveFour

In theory at least

[dry pebble]

What is the purpose of reverting it back to before MoveOne in combine move? Is this for the client's bookkeeping or for sending to the server?

[thin stratus]

The purpose I can't tell you, I didn't code it

The reason the have to revert is so that it doesn't perform MoveOne twice

The Combining itself is bandwidth saving

[dry pebble]

ahh perfect that's all I need to know then, how to use it. The why shall remain mysterious. 😄 Thanks Exi, you are so freaking helpful and knowledgeable.
I was just about to ask why they combine, but you answered, makes sense. if you're ticking too quickly, you'd be spamming the server so much more with FSavedMoves.

So without CombineWith and SetInitialPosition custom code, is stamina being changed three times in two frames? Frame n: stamina changed on client. Frame n + 1: Stamina changed from MoveOne and MoveTwo?

[thin stratus]

Yes

MoveOne and MoveCombined

It's still only two "PerformMovement" calls that end in your UpdateFromCharacterState code

But the second one ,due to being combined, has a "twice as high" (depends on the two moves) deltatime

@dry pebble

[jolly delta]

can we start subinstance of a game server ? like I have a GameLevel, and each game is redirected to a dedicated server of an instance of GameLevel or should i start it multiple time outside of the game ? (not so clear but if anyone understand)

[twilit radish]

If you're asking for multiple worlds per instance, then no. Unreal does not support this. If you're asking for Unreal to act as a proxy for multiple other Unreal instances then also no. That's up to you or your team to make sure of to make work.

[dry pebble]

thank you so much! It all works perfectly now 😄 :D!

[fresh cloud]

eXi, i ALSO have a cmc related question

theoretically, why does sending the old move exist?

well i mean i guess there's a REASON, right now i'm wrapping up my own implementation of network prediction interface and i think i fixed what was wrong before

i finished it up last night with autonomous <-> server sending single moves only

and the performance was good, after my fixes

now i implemented servermoveold (using the OLD style, not the new packed style)

it basically just sends an old, unack'd move, but doesn't ack it back

is the... ack not important for an older move?

(also what was wrong before was that uh... i was sending the FINAL rotation, not the starting rotation, and thus anytime rotation wasn't the same as the previous frame, i would always be off by about like 2-3 degrees of turning and that REALLY fucked up the prediction all around lol)

[twilit radish]

The server acknowledges movement packets because A) it may be a wrong move according to the server and needs to be corrected on the client B) the client can free up that move from memory afterwards.

[fresh cloud]

but, why not for old moves? i'm not sure if that was changed for the packed/single RPC functions of CMC, and when i was doing single move transfers that made sense

but when a server receives old move via ServerMoveOld, it doesn't ack it back, it just takes it

hm... i guess i should look at the new packed versions of the functions to make sure they didn't change it, but in the non-packed version, old move doesn't seem to have an ack at the end D: unless...

[twilit radish]

It would be very odd if they didn't have any ack whatsoever as that is a fundamental part of how server authoritative movement works right now 😛

[fresh cloud]

it verifies client time stamp, goes straight into moveauto, then doesn't ack at the end

yeah, it looks like the new single rpc function acks at the end, but OldMoves are always flagged as such and i guess it never gets ack'd?

[jolly delta]

yeah i am able to do that i just wanted to know if it is not native on unreal before dev anything lol i have doing work for nothing

[twilit radish]

Maybe that EOS can do dedicated server matchmaking, but not sure.

Also not sure if that's really considered a 'proxy' lol.

Although EOS still sounds too good to be true honestly. I'm still very suspicious of it xD

[cloud stirrup]

is there any way to pass things between levels? i.e i have a main menu level and a play level main menu is local i guess and play level is server side (dedicated) and i want to take a player name from the main menu to the play level. do i do that by passing in login info that returns a true berried inside the server with sockets/http using guid as the "its this player i should assign name to.

[cloud stirrup]

nvm another case of ask and find an answer that may suit. use open level and pass cmd line arg of username=xyz uuid=somenumberfromloginserver.

then serverside on beginplay load that cmd line to the player i think

[fresh cloud]

and final bug down: i was handling rotation as part of my PerformMovement implementation and using AddYawInput, but the changes of that are only committed to the ControlRotation during PlayerTick

i had to change my rotation handling to write directly and pull directly from the control rotation like the rest of my networking, but i think every setcontrolrotation should be clamped... other than that, everything should be nice and neat! i'm done with networking and can move on to other things in my project!

[glossy nimbus]

Hi, has anyone here had issues getting dedicated servers to work on UE 4.27? I keep getting this error and the only solution I've heard is to go from 4.27 to 4.26. Has anyone here found a fix for 4.27 or know why it is happening?

[neon mango]

Are you trying to open up a level as a listen server on a dedicated server? I'm not sure if that will work but haven't tried to spin up a dedicated server before.

[glossy nimbus]

I'm launching a dedicated server. It was working if I set it to a listen server, but launching a dedicated one started giving me issues.

I managed to get it to work just now by disabling all of the stuff related to OnlineSubsystemSteam in my DefaultEngine.ini.
The tutorial I followed told me to add all these commands, but I'm not trying to implement Steam integration yet.
My guess is that I haven't set up everything related to steam correctly so it can't list itself properly. Hopefully it will work fine when I get around to doing the Steam integration.

I am able to connect to my server via IP through the "Open Level" node, but I still cannot find it through the "Find Session" node.
I'm able to find the session if I host it as a listen server instead. Dedicated servers on LAN seems like they should be able to be found by the "Find Sessions" node, no? I have set DefaultPlatformService=Null in my DefaultEngine.ini and I can find it through listen servers but not through dedicated. Do I need to have an OnlineSubsystem like Steam/Epic to just find local dedicated server sessions on LAN?

[thin stratus]

Dedicated Servers don't magically create a Session though

Only because you start it doesn't mean it's Creating a Session

That's usually done in RegisterServer in AGameSession

At least when using C++

Without that, you won't find even LAN OSS NULL Sessions, cause there is none :P

@glossy nimbus

[glossy nimbus]

Ah, makes sense. Is an AGameSession created upon starting the dedicated server, or does it have to be called through a "Create Session" function?

[tranquil swallow]

Hey guys, I'm having an issue and I'm wondering if this thing is the issue.

Whenever a player dies it activates this spawn method, when the player dies, it will spawn a new actor and make the player possess it. The issue I'm currentlly having is this

Player A -- Server
Player B -- Client
Player C -- Client

Player B kills Player C, Player A then respawns.

Is it because I use Get player controller and it's index is 0 and how would I work around this and get it to possibly work

[thin stratus]

That's a class that exists already

Same as GameMode and such

You just need to make a child of it and override the get GameSessionClass function in the GM to return your own

And then override register Server

[glossy nimbus]

@thin stratus
I was able to get it to work. I just had to create a session in the level blueprint using the "Create Session" node using the IsDedicatedServer boolean

[thin stratus]

Alternatively you could just create your session in the GameMode BeginPlay locked behind is dedicated server

[glossy nimbus]

However it shows up twice with different pings

[glossy nimbus]

Yeah, that's what I tried to do now:)

Any idea why it shows up twice?

[thin stratus]

Not sure about that

Could be your UI not being cleared

[thin stratus]

Yeah don't use GerPlayerCharacter

[glossy nimbus]

I clear the children when hitting the search button. It looks like this:

[thin stratus]

You know who died cause you usually are in the Character, code-wise, when they die

After all you reduce their health variable

If you have a default pawn in your gamemode you can also just call restart player on the PlayerController

[tranquil swallow]

Well when they die it calls the spawn method

[thin stratus]

I can't read that. Not sure if the image is bad or discord on phone sucks

[tranquil swallow]

So when their health is detected to 0, them being dead is set to true and then a few things set off

Let me send a better one

[glossy nimbus]

The GetPlayerController will always give you the servers controller at ID 0 if it is a listen server

[thin stratus]

Why do you server RPC again at the end

You could just place that delay where you call the Multicast

Or limit that part to authority

The multicast already executes on the server

[tranquil swallow]

Because this spawn method wont only be called by the death method

[tranquil swallow]

Oh I know what you mean lol, brain fart

[glossy nimbus]

@thin stratus
Any idea why the server appears twice? I clear the children of the scroll box every time I click the search button. I'm not finding anyone with the same problem on google:S

[tranquil swallow]

Just didnt realise I had 2 delays

[thin stratus]

Does the search result really Return two elements?

[glossy nimbus]

Lemme check, 2 sec

[thin stratus]

Do you maybe still have a server running in the background?

Check task manager I guess

[tranquil swallow]

This is what's happening, its a bit weird

[glossy nimbus]

It does return two servers and the servers disappear if I close the one dedicated server window. Let me check if the IPs are the same

Task manager also shows that no extra instance is running

[thin stratus]

Try the native find session and create session nodes

Just in case the plugin is funky

I'm heading to bed now so you are on your own now :P good luck though

[glossy nimbus]

True, I'll try that quickly. I was able to find another workaround also since both servers return the same SessionID. I could filter it out by adding it to an array and checking if it is already in the array. The "Contains" node call might get more and more expensive if there is a lot of servers online.

[glossy nimbus]

Alright, thanks for your help!😀

[austere burrow]

Hey, I want to iterate over all the connected PlayerStates after a player logs out but during the OnLogout event, the exiting player is still included in GameState->PlayerList. Is there a nice way to only get players that are not exiting or is there a different event that I should be hooking into?

I can pass along the Exiting Controller but it'll take some refactoring. Just wanted to check I'm not missing something.

[austere burrow]

Solution: I'm calling my iterator function from PlayerController->OnEndPlay instead (only when it has authroity)

[hoary spear]

Guess there's no OnRep for the playerstate array

[dark edge]

It's not replicated, playerstates add themselves to it IIRC

[hoary spear]

My bad, I ment the playercontroller array^*, in the gamestate

[hoary spear]

Huh kinda surprised its not replicated 🤔🫨

I suppose now the local player always comes first, atleast

[glass vector]

How do you check if the host has disconnected, when playing as a client in a listen-server setup?
So you can quit session and go back to the main menu for eg

[agile loom]

I think the only way for a listen server is to ping it

Client call: ServerPing();
And then the server call ClientPong();

For example: use a timer and call the ServerPing(); every second

[sinful tree]

If the host disconnects all clients would be sent to the "Game Default Map" you've defined in your project settings.
There is a "Network Error" event that is present in the GameInstance that can be used to detect when unexpected client disconnects happen on the client side.

[agile loom]

Does this work even if the server crash?

[sinful tree]

Yep

Hmmmm... I take that back.

There is a connection timeout setting that after 60 seconds it will boot them back.

[/Script/OnlineSubsystemUtils.IpNetDriver]
InitialConnectTimeout=60.0
ConnectionTimeout=60.0

So if the host leaves (non-crash scenario) it'll boot everyone immediately. If it's a crash, the timeout will come into play but all clients will be booted back to the default map.

[agile loom]

Yes because during my tests I never received this error message that I implemented

[sinful tree]

The Network Error fires first, then the default level opens - you may not have enough time for your widget to be displayed before the engine automatically loads the new level which removes the widgets from the viewport.

[glass vector]

How do I check that a client has disconnected or left the session, as a host in a listen-server? ie, I want to clean up and remove player's pawn in the map after they have disconnected

[dusky yarrow]

there's a "logout" event in AGameModeBase that you can override

[thin stratus]

Player Pawns should already be destroyed though, unless we aren't talking about possessed ones

[glass vector]

that's strange, mine will freeze in place when a client disconnects

[thin stratus]

void APlayerController::PawnLeavingGame()
{
    if (GetPawn() != NULL)
    {
        GetPawn()->Destroy();
        SetPawn(NULL);
    }
}

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

Unless you override any of that, it should work automatically

Cause I usually know the opposite side where people are struggling to have the Pawn stay behind

[jolly delta]

hey is anyone know if i can trough the editor start a server with x standalone client that run a map A whereas server run map B ? if i use the server map name override setting it also start my client on the map B instead of A

[thin stratus]

Maybe if you uncheck UseSingleProcess?

[thin stratus]

Hm then not sure

[jolly delta]

so i guess i have to start everytime using a command meh

i can bypass it like that lol

[thin stratus]

Why would the Dedicated Server be on the MainMenu though

[jolly delta]

ahem, just do not care about name ahahah is it not really like it is supposed to be. Is it much more like a waiting room atm

[verbal tendon]

Shooting this into the void, just in case. I'm working on a more complex project that I can't share many details about. But I'm working on tooling that is present both internally during editor usage as well as on the target device at runtime. So I have a singleton that references the current gameinstance, and a gameinstance subsystem that registers and unregisters itself with the singleton.

This is because some of the tooling needs to be available from within the editor whilst there is no session in play, and other tooling needs a game session to update within the editor (PIE) or on the target device.

The obvious caveat here is that it won't work on dedicated servers. I doubt anyone else has run across this, but if someone has do holla.

[thin stratus]

Hm

Singleton is in some kind of extra Module?

[verbal tendon]

Yeah it's together with the sole purpose subsystem that sets and clears it, because order

[viral vortex]

Hello, tell me what is better to use for the open world, world composition or world partition?

[woeful ferry]

World partition since world composition is deprecated and I don’t think it’s not even in UE5

[jolly delta]

just to be sure if i do it right. To change level on a server (so on the game mode) i have to do a console command with a "serverTravel" right ??

[thin stratus]

Yes

[jolly delta]

but this do not wait for all players right so if i want to do specific behaviour like spawning on the level i should wait for all players travel ?

[thin stratus]

What do you mean with Wait for all Players?

[jolly delta]

i do that and just next to for each i have my spawn logic

it do not work as inted everytime but if i had a delay it seems to work

[thin stratus]

You should not spawn anything after calling ServerTravel though

Preferably ServerTravel is the last thing that should be called

You can spawn again once the Travel is over

[jolly delta]

so i have to do something like :
open level -> spawn -> server travel instead
travel -> spawn ?

i am not so familiar with the online logic

[thin stratus]

No

What do you want to spawn?

ServerTravel moves from current to the new level

That means also a new UWorld

Everything you spawn before ServerTraveling is usually lost (unless specifically preserved via C++)

[jolly delta]

atm i am in scene A like waiting room
i need to switch everyone on scene B (that is why i do a travel)

scene B is where everyone is so i need to spawn every player on the world

[thin stratus]

Yeah the you will need to handle spawning after the travel

E.g. in your new GameMode on BeginPlay or even just through the already existing spawn code of the DefaultPawn

SceneA and SceneB should preferably have different GameMode classes assigned

fwiw with the same parent if needed

GameMode of SceneB can then spawn the Pawns for the Players

[jolly delta]

to change gamemode on command i have to do ServerTravel Map?game=Gamemode ?

[thin stratus]

Yeah but only if you have one map that can have multiple gamemodes

Otherwise that's not needed

[idle wagon]

Hi! Quick question regarding multiplayer and "Set viewport mouse capture mode". I've been trying to fix an issue I have been experiencing when the server hosts the game, then afterwards client(s) joins the game and suddenly mouse clicks stop working. Mouse axis/movement still works, but mouse1 and mouse2 stops working. This does not happen to client1 when client2 joins, only server. On beginplay on the controller I set "capture permanently" for capture mode, if server/clients join the game at the same time this problem doesn't occur. What solved the issue was changing the capture mode to "Capture Permanently including initial mouse down". I just don't understand why this change would fix the problem, and capture mode never changes on the server controller when clients join.. Any ideas?

[timid moat]

Hi! Do I need a session if I want to join a multiplayer game? In other words, is it mandatory to have a session in a multiplayer game?

[latent heart]

No

Sessions are just a kind of meta thing. You could literally just join a server directly without them.

[timid moat]

OK. Thanks.

[subtle patio]

If your end goal is dedicated servers, you essentially need to develop for them from the start right? It's not a case of building a listen server model and converting it later, the architectures are significantly different enough that I need to be working with a dedicated mindset from the get go?

The more I typed that, the more I answered my own question I think..

[subtle patio]

No 😅 when in these big channels, messages tend to overlap, unless you are directly pinged you can assume usually people aren't talking to directly to you

Unless the context makes sense

[cloud stirrup]

id go dedicated from the outset.

i had an isse when going from a simple made project to decide to dedi server it just converting it to c++ broke it. so i started again from a base dedi client build. now it seems to be going alright. except iv no clue on how to get the "users details" from the mian menu to the dedicated servers map.

[sinful tree]

Listen servers vs. dedicated servers you basically just need to consider that on a listen server the host is effectively also a client, so your logic needs to take that into account, and if you don't then you'd end up having to go through all of your logic to fix it up later.

An example of an issue you could face would be using an Authority check on something where you may only want "clients" to execute a function, but in reality, the host is also a client and should probably execute the function too, so the authority check isn't sufficient for what you're attempting to do.

[cloud stirrup]

i had tried using cmd line inputs but seems they can only bee booleans and ints you can grab back out of it. so my next thought is sockets or something where id login req a pawn id load pawn ready and connect client with pawnid as the argument but thats a bit ridiculous as u could spam some random numbers as a hack and log into a random pawn....

[subtle patio]

Yeah i suppose my question was: is that process of fixing up later worth it given the overheads with dedicated models (building from source, having to add extra builds and ultimately host the thing) but i feel like the answer is no, I may aswell just put in that bit of work upfront and develop the game for the intended "final form"

[hollow eagle]

You don't really have to

You can run a launcher build as if it were only a server just for testing purposes. It won't be using the actual dedicated server config, but it's fine for testing in the editor.

The important thing is to be building for multiplayer from the outset

Sticking with good practices and regularly testing in both listen server and separate server modes (if you need both) will get you most of the way until you get to a point where you really need to start testing things.

The editor has lots of options around testing these different scenarios and while they won't catch everything they're fine to start with.

[sinful tree]

Fixing it later rather than developing it to work for both as you go could take significantly more time as you would have to track down all the spots where such networking could happen.
Even if you eventually decided to scrap the idea of allowing dedicated servers, the logic will still work if you design your code for both but only use listen servers. It's not a big difference between the two in terms of coding, but rather the issue is that there is a difference, and that difference can be in hundreds of places depending on what your code needs to do.

[hollow eagle]

They're asking about the actual need to start using dedicated server builds from the start.
Which should be an emphatic no since you can run normal game configs in server mode for testing purposes.

Most devs won't be working with real dedicated server builds except when specifically debugging issues with that build config anyway.

You're fine to start developing without it as long as you're working with it in mind - don't make assumptions about every instance of the game having a local player is the most important piece. And then test with separate server instances both in PIE and standalone when necessary.

The issues that will crop up in dedicated server builds later are primarily around actual compilation issues, and optimization (removing unnecessary logic and assets from server builds). Neither of which should be big concerns near the start of a project.

[lunar junco]

can't you run a "dedicated" server instance that doesn't have a player inside the editor when testing locally?

[hollow eagle]

Yes

That's what I'm saying

[lunar junco]

problem solved then lmao

just deal with it during deployment

[hollow eagle]

You'd want a real server build from source eventually but it's not something you have to plan for early on.

[tiny finch]

how can you stop players from connecting to your session when the host is in game and not in lobby map ?

[hollow eagle]

override PreLogin on the gamemode

[cloud stirrup]

this says it is a hardware idso i guess if i changed the right something about the hardware it would change

[obsidian basin]

Anyone know how to convert jump velocity to something I can calculate distance for a skill?

For example, say I have a character Jump skill of 100. I want to convert to a 10-1 so they would jump 10 feet (High I know, but just as an example)

[dire cradle]

Not sure how this is relevant, but just divide by 10 ?

[obsidian basin]

Oh wrong room, my bad

[obsidian basin]

Thought I was in #blueprint 😄

[austere burrow]

Question: When calling PlayerState->GetPlayerController the tool tip says it will return null for remote clients. Is this a reliable way to branch on "is player locally controlled?" Specifically when the function is called from a listen server, is it expected to return null for remote players even though a corresponding PlayerController exists on the server?

[lunar junco]

if the player is locally controlled, then yes, it should not be null

if you're skeptical, just put a null check and a warning

[austere burrow]

and the inverse - if it's not locally controlled will it definitely be null?

[lunar junco]

I would think so? Though I'm not sure, UE can be vague with the terms

I'd say the best way would be to test in editor and see

[austere burrow]

Yeah - I'm getting the behavior I want but the terms were confusing me. Originally I was calling GetPlayerController->IsLocalPlayerController on the server and I was surprised to get null exceptions. It seems like GetPlayerController itself is enough to verify locality. Thanks for your thoughts

[fresh cloud]

yeah because local player controller is null for servers, all playercontrollers on the server are netconnection based

playercontrollers on a client, for the local player, are localplayer based

[austere burrow]

Sorry I should have specified, it's a listen server not dedicated. So it has one local controller.

[fresh cloud]

ah yeah! sorry, i've been in dedi server brain mode because of my project

[austere burrow]

all good! :)

[hollow eagle]

In single-process mode the exact same place that the rest of PIE lives. It's not doing anything special when running a PIE server, it's just starting a hidden PIE instance in server mode.
When running in multi-process mode it's just running a normal standalone instance with -server and whatever other arguments are necessary.

UNetDriver and UNetConnection are the start of the higher level framework (above udp).

They're not specific to the server.

also see https://docs.unrealengine.com/4.27/en-US/InteractiveExperiences/Networking/Actors/ReplicationFlow/

Also "what is responsible for being the authority" is the wrong way of looking at things. There is no singular authority, every actor has the potential to be the authority on the current game instance or not.
Clients can be the authority for an actor. With the built in net driver that'll only happen when an actor only exists on that client (or if it's torn off), but the same concept would work if you managed to do a bunch of custom work for a true p2p setup.

I don't believe there'd ever be an instance where the server is not the authority for an actor that exists on it, but again the authority system isn't just for server-authoritative networking and would work with p2p if you provided a driver for it.

[lunar junco]

I'm pretty sure it creates the same game model and just doesn't create a player

[hollow eagle]

For the most part, yes.

[glass vector]

how do I check if I'm already in a multiplayer game? ie, I have a widget that I want to display differently to Host, Client, Standalone.

[hollow eagle]

GetNetMode

[glass vector]

is there a BP node version?

can't find it

[timid moat]

Sorry, I don't understand you. I read it in this order, so I answered Darkest.

[arctic minnow]

could someone help me fix a problem where my damage is different on server and client like if I hit client on server it dose less but if I hit server on client it dose more thank you!! 🙂

[cloud stirrup]

iv done this in last project but decided to restart it. and im not sure why i keep getting blank for options string this time round. any thoughts...

serverlog
client call
server game mode.

[thin stratus]

It will return null where a PlayerController for this Player doesn't exist

Server and owning Client will have a valid Pointer. If you want to know if it's locally controlled you will still need to check that on the Server, cause with x players, the Server will have access to all x PlayerController. Only its own (ListenServer) will return true for IsLocalPlayerController

Also I noticed my chat didn't scroll apparently, so if this was already answered then sorry for the ping :P

[thin stratus]

The Options String is not for Player Connections

The Options String that players provide is not available in BPs

[thin stratus]

You'll need to post your damage logic. Otherwise probably no one will engage your question

[austere burrow]

Any clue as to why I would sometimes (but not always) get an access violation on the indicated line? FocusTarget is an AActor*

{
    // Look at focus target.
    const FVector EyeLocation = GetCharacter()->GetActorLocation() + DefaultCameraOffset;
--->    const FVector ToFocusTarget = FocusTarget->GetActorLocation() - EyeLocation;
    ...
}```

[austere burrow]

No worries! The explanation helped solidify my understanding so thanks

[thin stratus]

Testing UObjects via if (Object) isn't enough

The Pointer can be nullptr, and you are guarding against that, but they can also be pendingkill (at least actors can)

And PendingKill is a valid pointer in a "soon to be destroyed" state that will also cause this

You should get used to using IsValid(Object)

That checks on PendingKill

[austere burrow]

Is there a way for UObjects to be invalid at the start of the life cycle? It seems to crash at the start of a multiplayer session or not at all

[thin stratus]

Not to my knowledge

PendingKill is when they are marked as Destroy

[austere burrow]

right, yeah

IsValid is a good habit anyway, thanks

this code is in the player controller btw and crash only seems to happen on client (not positive though since it's been sporadic)

[thin stratus]

There isn't much I can say about it. You'll need to catch it with your IDE connected and check the callstack etc.

[jolly delta]

when i do a spawn Actor on my gamemode and then possess it it is supposed to be spawn on every clients ?

[sacred fractal]

Hello 🙂 i'm making this prototype-game about 2 mounts. And want to show you my wip-video =))
Developing in solo. Unreal 5.1 (very good version!) , using AdvancedSteamSessions plugin. My english is very poor, sry!
https://www.youtube.com/watch?v=y8jtRRzgBEQ

[jolly delta]

is that is good ? like is this suppose to spawn a top down character on every clients and server ?

[bronze mauve]

You should check HasAuthority and only spawn it on the server.

If the character is replicated then it will automatically spawn in on clients too but the server will own it.

[jolly delta]

is it on gamemode is it always on server no ?

[bronze mauve]

Oh, yes if this is in the game mode, it's always on the server, no need to check HasAuthoeiry then 🙂

[hot garnet]

Hi all, Need some advice, im making a character creation system in my project and i have coded this for changing the mesh for the hair, on the local character it updates the skeletal mesh of the hair but it doesnt replicate the change for everyone in the server. What am i missing?

[weak linden]

Is there a reason you're not just using the default pawn class option in the gamemode? This seems like a very backwards way to spawn a/the player character

[jolly delta]

because i saw someone doing that so i tried like that ahaha is there a better way to that ? atm
i have a lobby then when all player has join i do a server travel to the main game where i init all actor and then throw an event that spawn the "playersactors" on game mode

maybe my logic is not good but as a beginer i work as i understand ahahaha

[weak linden]

Yes, there's definitely a better way to spawn a character for each player when they connect, give me a few mins and I'll find my BP version of my spawn system for you

[bronze mauve]

Yeah Kamikaze has a point, you can just set the default pawn on the game mode and it will automatically spawn all characters for you. You just place PlayerStarts in the world and the default pawns spawn at the PlayerStarts

[weak linden]

I imagine it's also possible that doing that on BeginPlay might not even work (the game mode is responsible for spawning the controllers and BeginPlay will almost always fire before the first controller is even set)

Not to mention that GetPlayerController with 0 will always return the first controller

I.E only the first player will get their character

[bronze mauve]

In multiplayer things are weird, like the characters spawn in and may not even have a valid player state/controller for the first few frames... but at least the game mode will get around to connecting them eventually, and player controllers will end up possessing the pawns automagically

[sinful tree]

If you're doing this in GameMode, there is "Handling Starting New Player" event in the game mode which if I recall right is normally where the character is spawned. It gives a controller reference you can use from the event as well.

You want to avoid using "Get Player Controller" unless you know for sure you're running something locally as you won't have the appropriate reference to which player controller on the server.