multiplayer

[chrome bay]

Yeah but then the OnRep is still called server side, which is stupid

Since nothing is replicating

[near bison]

then I guess do a hasAuthority check?

[chrome bay]

You can workaround it, it's just silly that it works differently in each domain

[near bison]

still sounds unnecessary though, you're right

two takeaways:

1. update repnotified vars only on server, 2) hasAuthority check if required to run repNotify only on clients

[pallid mesa]

++ BP's onrep also get called when the variable doesn't change ie: setting the number 7.f twice to a float var 🤷‍♂️ (I thought this wasn't the case, got me all surprised actually)

[chrome bay]

lol fabulous

[near bison]

does anyone build games with BP at all?

[pallid mesa]

it's a tool

[chrome bay]

It's certainly used. Just IMO has a low ceiling when talking multiplayer in particular

[crisp wraith]

Yeah, I am currently using owner of the actor component as outer. What do you mean by crashes, is it fine replicating UObjects from server to clients or should I rather choose another method?

[near bison]

no I mean full games.
I'm building one right now...not seeing too many issues

[near bison]

I am mindful of this however, + lots of unity MP experience

[chrome bay]

It's definitely been done I think yeah

[near bison]

it's definitely irritating that I don't have access to PlayerArray in GameState for like the first 2 seconds

[chrome bay]

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

have a read through that if you haven't already

[pallid mesa]

Galaxy in Turmoil runs most of its logic in BP's and it's a multiplayer game...

it doesn't scale very well, but it runs okay

[near bison]

It's got mostly negative reviews

[pallid mesa]

mhm, yeah it didn't do very well x'D

but anyways, it's an example that it's indeed possible

[chrome bay]

Def possible, just... tedious

And yeah scaling up becomes an issue, doesn't matter if it's a simple game though

[near bison]

scaling up means?

yeah I'm building a simple board game

[chrome bay]

Like lots of players or high-complexity game etc.

[near bison]

we're going blazing fast with BPs

[chrome bay]

Yeah that's probably fine tbh

[pallid mesa]

oh also BP multiplayer got some gotchas

[near bison]

such as/

[pallid mesa]

because of UE initialization code

waiting for PS and whatnot

things that aren't exposed in BP's

[crisp wraith]

Thank you, will take a look. One thing I didn't see when skimming through, is changing outer to another actor (if I move the UObject to another owner). Can I go with UObject::Rename(..) or rather duplicate and discard old one?

[chrome bay]

I haven't tried moving them between outers, but I'm pretty certain it would break under some situations, especially if data about that object is still replicating on that channel when it's destroyed.

[near bison]

interesting..
it's cool, doubt we'll run into anything major

BPs for board games seem fine to me 🙂

[pallid mesa]

oh you will in the UI for sure

[near bison]

oh god

such as?

what UI?

[crisp wraith]

Ah, thanks

[chrome bay]

The difficulty in BP is coding around the inherent race conditions you get from the networking system, they're quite easy to get around in CPP because you can override a lot of engine behaviour - but in BP a lot of that is not exposed.

[pallid mesa]

^ correct ^

can't remember all the examples

but for example GS replication

your PC is alive in the client and the GS isn't yet anyways

so u have to wait for it

[chrome bay]

Basically you can never rely on an actor to be around when you access it, so it boils down to a lot of events etc.

[pallid mesa]

in BP's you can do this with a simple waiting loop or sm

but yeah the correct way to do it is to hook on begin play and propagate existence

[near bison]

incredibly tedious

[pallid mesa]

in C++ you can use other hooks that ease your job

[near bison]

such as?

[pallid mesa]

as the non-virtual setplayerstate

that cannot even be overriden in C++ 😭

well one example is onrep_playerstate in the character (i believe it was)

[chrome bay]

It could be anything really

[pallid mesa]

but yeah these are just implementation details...

if you get any of these just come here and ask

[near bison]

yeah

exactly

[pallid mesa]

it's tough for starters

[near bison]

2 second delay works for me now...probably will switch to propagating event from PlayerState in the future

[chrome bay]

It's one of those things you can only get your head around once you start experiencing it really

[pallid mesa]

don't

[near bison]

why

[pallid mesa]

rather than 2 second delay, loop it

loop the delay until is valid

it's an atrocity, I know, but it's safer

[near bison]

like, a while loop? how would I write this?

[opal fox]

Think just finding a good mix of bp - cpp works fine

[near bison]

and what am I actually waiting for?

[chrome bay]

It can be useful (and this is commonly the approach in CPP also), to create just a core system you can access from anywhere at anytime - and it contains some global events you can bind to

[pallid mesa]

is there any online BP editor I could use to show you?

[chrome bay]

E.g. "PlayerStateReceived", "GameStateReceived" etc etc

[near bison]

probably just a diagram would do

[opal fox]

Ive found it nice for most base classes created to just define as much as possible in C plus plus and then extend outwards from blueprint

[near bison]

can I use the PostLogin event?

[pallid mesa]

@near bison enjoy 🤣

[near bison]

How can I do isValid on a playerStateArray

[pallid mesa]

uh what do you want to do with the ps array?

ah u want to check if every member in the array is there,right?

then instead of doing isvalid

do array.length == quantity

[near bison]

but how do I know the quantity before hand?

[pallid mesa]

is it predefined?

or what do you need exactly

[near bison]

well it's predefined for now

but might be different well into the future

it's a board game

[opal fox]

just loop the array and check if the content is valid?

[chrome bay]

Presumably you want whatever it is to respond to players being added/removed dynamically

Which will happen

If players leave, join in progress etc.

[pallid mesa]

right, there is no a BP handler for that afaik, but you can do postlogin

but that's not for PS's

[chrome bay]

I think GS has overrideable functions for players being added/removed no?

[pallid mesa]

also only server

actually not sure, I know for a fact they are there for C++

[chrome bay]

Can't remember if they are BP event funcs

[near bison]

i cant find a player added node in GameState

[pallid mesa]

sheesh x'D

[chrome bay]

Oh lel, yeah it's CPP only

[near bison]

should I use delay or a while loop here?

[chrome bay]

virtual void RemovePlayerState(APlayerState* PlayerState);```

Would be useful to have an event by default tbh

[pallid mesa]

if u want to check for quantity, use a delay + length check

yes well james, at least they are virtual x'D

[near bison]

but how long do I delay for?

[pallid mesa]

this thing but isntead isvalid

u get the array and do length == whatever number

[chrome bay]

Just an example of what I meant by having a central object that has events:

{
    Super::AddPlayerState(PlayerState);

    if (UHT_WorldEventManager* WEM = UHT_WorldEventManager::Get(this))
    {
        WEM->NotifyPlayerArrayUpdated(this);
    }
}

void AHT_GameState::RemovePlayerState(APlayerState* PlayerState)
{
    Super::RemovePlayerState(PlayerState);

    if (UHT_WorldEventManager* WEM = UHT_WorldEventManager::Get(this))
    {
        WEM->NotifyPlayerArrayUpdated(this);
    }
}```

[near bison]

??

[pallid mesa]

the if branch

[pallid mesa]

what would you have in the notify player array updated body?

i find it a pretty nice idea, might steal it 😄

[chrome bay]

{
    check(IsValid(InGS));
    checkSlow(InGS->GetWorld() == GetWorld());

    ConditionalBroadcastNetworkReady();
    OnPlayerArrayUpdate.Broadcast(InGS, InGS->PlayerArray);
}```

[pallid mesa]

aaah I see a delegater 😎

[chrome bay]

Then you can do fun stuff like this:

{
    Super::NativeOnInitialized();

    if (!IsDesignTime())
    {
        UHT_WorldEventManager::NetReadyExecute(this, UHT_WorldEventManager::FOnNetworkReady::FDelegate::CreateUObject(this, &UHTG_DropzoneUI_WavePanel::NetSafeInitialize));
    }
}```

And not have to worry about UI trying to access missing stuff all the time

[pallid mesa]

badonkers

actually this could pretty well belong to the engine

[chrome bay]

It should be tbh

[near bison]

the fact that I have to do this

[chrome bay]

Might dump this somewhere

[near bison]

is so dumb

[pallid mesa]

worth a blog post for sure! I'll link it around if you do, I know some people that will be happy about that

[pallid mesa]

can you tell me where u are executing that code?

[near bison]

gamestate

when all the players are connected, I want to shuffle their turn order. that's why I'm calling a simple function on gamestate

[pallid mesa]

ah! aaah! okay

not exactly the problem i was trying to solve

but it works aswell in that case

🤣

[near bison]

well, yep

and only once this turn order is setup, will I fire an event

that enables everybody's UI

ez. lol. game the system

[pallid mesa]

gtg now! good friday

[near bison]

thanks @pallid mesa and everybody else 🙂

[pallid mesa]

James, if you remember, ping me when you post that stuff! 😄

[pseudo merlin]

thanks!

[hard hinge]

 Malformed_Packet: Received packet with 0's in last byte of packet

What does this mean?

I'm using online subsystem steam

It's very difficult to debug server issues on Linux

This error cannot be searched for sadly

Errors should be searchable

[young lily]

not sure if this is going to help you, but I can find the error string in a unit test, and in Engine/Source/Runtime/Engine/Private/NetConnection.cpp

I used the search string

Received packet with 0's in last byte of packet

[hard hinge]

Yeah I found that eventually

Sadly it's not helpful yet.

Trying some stuff

[dark edge]

If the missile is a REPLICATED ACTOR then the clients will see it too when it spawns on the server.

[little finch]

No, online multiplayer

[dusky yoke]

Oh yeah, that part is working now 🙂 One thing thats occured now is that the missiles disappears right before impact for clients, I think it has something to do with the replication culling... could it be too huge numbers maybe?

[dark edge]

The launcher (which is a replicated actor) spawns missiles (which are replicated actors), whos movement may or may not need to be replicated (depends on if they move in such a way that can't just be predicted by their initial transform and velocity)

How many missiles are you talking?

How you do it will depend on if it's a couple missiles or hundreds or thousands

[winged badger]

you generally don't destroy replicated Actors server side right away

hide them, turn off their collisions, turn off their tick, and set their lifespan for a few seconds

[gleaming kite]

I feel like im doing something wrong but how do I set a class to use a certain player state? Trying to have a certain player state for each character

[dusky yoke]

Aah, Im firing 4-8 missiles, but I'll try to add a higher cull distance value to test it out @dark edge - I gotta do the same thing for my characters as I want their gunshots to be heard across the map 😅

[fathom aspen]

APawn::SetPlayerState in C++

[hard hinge]

CLOSE_CONNECTION_DUE_TO_SECURITY_VIOLATION(this, ESecurityEvent::Malformed_Packet, TEXT("Received packet with 0's in last byte of packet"));

Whenever I try to connect to my dedicated server, I get this warning printed and the connection is lost.

Has anyone seen this

[deep shore]

if an actor contains a camera component that is active, but has no player as its view target, is this a large amount of wasted resources? are resources wasted by the server only, or does this also hurt clients?

the logical solution is only activating the cameras when a client is set as the view target. but I seem to be having an authority issue that prevents clients from activating/deactivating cameras unless they are set to auto-activate.

activating the cameras on the server does not activate them for clients, according to print strings. but activating them on clients has no effect.

[fathom aspen]

Honestly I wouldn't care about this too much if spectating can happen to often in my game, as the overhead of activating/deactivating would be higher than leaving them as is(at least that's the case in our game)

[fathom aspen]

So you are saying after you set the cameras to auto-activate, still they are not activating? not being set as view target?

[deep shore]

they are working fine for clients if set to auto-activate. which is fine by me, except there’s a lot of cameras and i’m worried about the performance costs

[winged badger]

the only cost for not used cameras is their transform updates and tick, if anything runs on it

[fathom aspen]

Which isn't a big deal?

[winged badger]

you should not be worrying about performance until you have something that works

and then only if the performance is terrible

later on, you use profiler, see whats costing a lot and try to optimize it

[fathom aspen]

Fair enough, makes total sense to me

[winged badger]

generally, no

[deep shore]

that helps. thank you!

[dark edge]

Are your projectiles pretty predictable or no?

[winged badger]

Problem with spawning a replicated Actor that spawns 6-8 other replicated Actors is that it all works nicely on empty test level

then it breaks when there are couple of hundred replicated actors around

evaluating Actors for replication takes time and CPU on server

[dusky yoke]

Yeah, they hit pretty predictably now 🙂

[winged badger]

and then you get a short lived Actor, like your missiles, and it just doesn't get its turn to replicate to clients before its lifetime already expired on server

and then clients don't see missiles

[fathom aspen]

That's why a replication graph is needed for such cases, right?

[winged badger]

as long as server can provide good predictable target information at the time it spawns whatever launches the missiles

[dark edge]

If their movement is decently predictable then just replicate their firing

same for your gun bullets

[winged badger]

you can have that information replicated inside the launcher actor, and have the clients spawn missiles locally themselves

[dark edge]

Be warned, if you have air drag in your projectile calculations it WON'T be predictable compared to a pure ballistic trajectory.

[winged badger]

i use a custom push model for replicating 85% of my Actors

none of my pickups or interactable actors are actually replicated, i have a network manager actors with fastarrays replicating few hundred actors each

[fathom aspen]

So you spawn most of the stuff locally on the client

i have a network manager actors with fastarrays replicating few hundred actors each
I have seen this mentioned quite a few times. Never used FastArrays myself, but should look into them at some point

[winged badger]

they are still netaddressable

as i need a pointer to the actor replicated as part of the fastarrayitem struct

but we spawn entire level locally on clients, then network it afterwards

[fathom aspen]

I see, they are netaddresable from the fast arrays

[winged badger]

no, they are net addressable because all machines spawn them in exact same location with exact same name, and IsFullNameSupportedForNetworking returns true

we also add a small... "hack" to make the engine behave as if they were loaded from the level, instead of spawned at runtime

[dark edge]

Would you recommend going down that route for a multiplayer game with procedural levels or is it a lot of trouble?

[winged badger]

i would, you can't replicate few thousand actors

and even if you could, relevancy behavior of destroying non relevant replicated actors would bury you

[dark edge]

In our case the only actors that would need to be replicated are doors etc, things that move.

All the level geometry can be derived from the seed

[winged badger]

we spawn 50k actors procedurally on larger levels

around 3000 of those need to replicate during gameplay, and that is where network managers come in

we also spawn them from seed, ofc

there are a few traps along the way

[dark edge]

Ours is a top down tile-based system, using WFC for map generation. So really, we won't be doing generation on the client but just replicating the tilemap and every machine interprets it into meshes etc.

[winged badger]

you can't replicate any of the procedurally spawned actors to clients until clients have completed procedural generation

when you set bNetStartupActor and bNetLoadOnClient true

unreal will assign them static NetGUIDs (last bit in the guid is static/dynamic)

unreal then also expects that when it sends a NetGUID for such an Actor that client, which has loaded a level at this point, has that Actor already and can Ack the NetGUID

if client didn't spawn the Actor already, they will still be NetAddresable, but you won't be able to open the ActorChannel

as in ServerOpenDoor(ADoor* MyProcedurallySpawnedDoor); would work just fine

but if you relied on the door to replicate its open state, client would be able to pen the door, but not see it opened

[dark edge]

Does this sound gross or ok? This is the current model.
On travel to a new map (nothing is actually loaded, we have 1 persistent level and that's it)

1. Server generates tilemap.
2. Server and client interpret tilemap into meshes etc. Most of the level is there by now, besides actual actors that do stuff.
3. Server spawns replicated actors (doors, enemies, interactables)

[winged badger]

it works, but can be improved

[dark edge]

All of this is hidden by a "travel" phase. The gameplay loop is sorta like Diablo with it's town -> dungeon -> back to town paradigm but it's spaceship -> surface -> back to spaceship

[winged badger]

if you used the same seed to spawn the replicated Actors generating their name as they are spawned with FActorSpawnParameters

setting bNetLoadOnClient and bNetStartupActor to true

and letting the clients spawn their own versions of those replicated Actors

with IsFullNameSupportedForNetworking returning true for those Actors

[dark edge]

So what do I end up with, a replicated DoorManager and CharacterManager and BulletManager etc?

instead of 30 replicated doors and 100 replicated characters etc?

[winged badger]

and IsNetRelevantFor on those Actors returning false until client RPCs that it finished spawning the level

you could have clients spawn the replicated Actors themselves, and just have them replicated after that

[dark edge]

I don't really see what advantage that gives me though, there's no hurry in the spawning really.

[winged badger]

with us, the level takes 10-15 seconds to spawn on a fast PC, if we had to replicate those Actors, it would be minutes

[dark edge]

oh ya in our case it takes like 2 seconds lol

you might have a lot bigger level

[winged badger]

but generally

(generic case)

if you had a FFastArraySerializer with FFastArrayItem that has a TWeakObjectPtr<AMinorReplicatedActor> and a TArray<uint8> ActorState as members

and that AMinorReplicatedActor (or interface) had a PostReplication function in it

you can wire a PostReplicatedChange/Add in FastArrayItem to call that function on the Actor the struct has a pointer to, passing in that ActorState as an argument

and have those MinorReplicatedActors be responsible for encoding and decoding their state from an array of bytes

which would in turn allow you to turn their replication off, or in your case set them dormant

and when they'd need to replicate something, they'd encode their ActorState, update their FastArrayItem and MarkItemDirty in the replicated NetworkManager that has the FastArray

and the replication callbacks from FastArrayItems would cause those Actors to update on clients

[dark edge]

Yeah that sounds like a crap ton of work lol. Maybe we'll hire that out if it gets to that point.

[winged badger]

i got it working in 2 days, without having done it before

and it had side benefits, like with few network managers, you can configure their NetPriority and NetUpdateFrequency to be higher

making the replication feel much much more reliable

[obsidian gyro]

I have a problem where The client can see the host's full head/gun rotation, but the host can't see the client's head/gun rotation, the clients bullets(which are shot from the rotation of its camera) are never able to shoot upward or downward because the host sees the clients head as not moving up or down, how do I fix this?

[dark edge]

So if I get what you're saying, this is replacing the regular replicated properties system with network managers that replicated some state as bytes to be interpreted by whatever actors.

[winged badger]

even unreal a significant network load

you don't have to use array of bytes

depending on how many different actors you need done this way

you can have a fast array for each actor type, if you have few enough

then you don't need to encode or decode anything

[dark edge]

ActorState is the payload though right? That's what's being replicated around?

[winged badger]

yes

and i run several different fastarrays inside network managers

one fastarray handles interaction, one handles damage/death, one replicated gameplay tags, 4th replicates buffs

and a more complex actor can actually use all 4 of them, each replicating one aspect of that actor

as there are like 300-400 different actor classes we replicate in this manner

[fathom aspen]

Wow, seems like you created your own replication system...hands down!

[winged badger]

the TArray<uint8> is the form that can generically handle any data, so it was easiest to use as an example here

[dark edge]

Seems like this would mesh with Subsystems pretty decently

[winged badger]

sure, but you don't actually need a subsystem, as network manager here has only one resposnibility

and splitting that responsibility with a subsystem just muddles the code

[dark edge]

If your BuffNetworkManager also did all your Buff logic it'd be pretty close

[winged badger]

yeah, but i don't have a BuffNetworkManager

[dark edge]

All roads lead to ECS i suppose

[winged badger]

i have a NetworkManager that has 4 FastArrays

the callback logic is inside the FastArrayItem structs

[dark edge]

How do you do movement then?

[winged badger]

things that replicate movement replicate normally 😄

they don't run via network managers

replicating several hundred moving Actors is doable

replicating several hundred moving Actors while you have several thousand non moving replicated Actors cluttering the NetBraoadcastTick is not

[dark edge]

If we ever get replicated Subsystems there might be an interesting endgame there. I really like just having lots of dumb data on objects and letting a manager do all the logic. It seems like the manager would also be the optimal place to handle the networking as well.

Our projectiles work like that, they're just data in a subsystem.

[winged badger]

only subsystem i see happening replicated is a GameStateSubsystem

it wouldn't be too difficult to create either

you need an ActorChannel to replicate it, and none of current available subsystem Outers are Actors

the only one that makes sense, and can guarantee it will be around is GameState, with GameMode not being replicated

could in theory pull it off on ALevelScriptActor, too

unreal has a nasty habit of swapping the Outer on a replicated subobject to be the Actor that replicated it via its channel

so while you could in theory put AWorldSubsystemReplicator Actor on the level, and have it gather and replicate all instances of WorldSubsystems you have running, client side those Subsystems would end up being A - Additional instances in addition to client run ones, and B - that WorldSubsystemReplicator, and not the World would be their Outer

[dark edge]

I suppose a component on GameState would make more sense then a subsystem

[winged badger]

which is still not insurmountable, provided you stop those Subsystems initializing on clients

you would not be able to access them via GetWorld()->GetSubsystem<T>() without additional hackery

but they would work

(like manually inserting them into World's subsystem collection during the AWorldSubsystemReplicator::OnSubobjectCreatedFromReplication

[severe nymph]

Anyone ever ran into a situation where a replicated server spawned AI thinks it's in the air on the client (spamming true/false)

but stays false on server?

default walking mode is navmesh walking

[winged badger]

you probably have MovementMode NavMeshWalking on server and regular Walking on client

[severe nymph]

what?

movement component is replicated by default

including this property

[winged badger]

so server correct teleports it onto the NavMesh, which is typically 30 UU above the actual floor

and then it starts falling to the floor

and CMC doesn't really do much replication directly

[severe nymph]

ok?

[winged badger]

so set your MovementMode to NavMeshWalking on client on say, BeginPlay

[severe nymph]

its one of the most expesive things in the netstack

[winged badger]

and it should fix it

[severe nymph]

when profiling

but ok ...

[winged badger]

oh, its sends plenty of RPCs, but its entire replication is wired over the Character

[severe nymph]

the thing is

if your familar with networking

when you spawn on authority

which is server

you don't actually have a net load client version

to be "out of sync"

to set a "different" walking mode on

[winged badger]

i agree it should be in sync

[severe nymph]

as your relying on the "replicated" actor

[winged badger]

but i have seen that problem before

unreal engine is not perfect

[severe nymph]

I have a feeling the recast is hosed

and nav needs to be regenerated

[chrome spear]

Just curious about this. In this sort of situation with a net static actor. How do you differentiate an on rep being once the actors come back to relevancy or has been in relevancy? Because with a dynamic one or with net load on client off it will always retrigger the begin play, right?

[severe nymph]

net load on client just means the client has a copy on net load which calls "client begin play"

[chrome spear]

It also causes the client version to be removed when you’re out of range

[severe nymph]

meaning any "states" shouldn't be init on begin play

[chrome spear]

Because static net actors stay

[winged badger]

no, static actors will just do a full replication when they become repevant

[chrome spear]

But they’ll just not be replicated

[winged badger]

dynamic actors are destroyed when not relevant and respawned when relevant again

which in turn causes BeginPlay to happen "again", but not really as its not the same instance as before

@severe nymph you got navmesh generated on client?

that is the second thing i can think off can cause this behavior

@chrome spear after the first replication of the Actor (which happens before BeginPlay) PostNetInit is called

[chrome spear]

So, can you tell in the onrep if it’s a full replication or not from net driver or something? In a situation with a door where you have animations onrep, for instance, you can use the begin play to skip the animations and just dodge the onrep with a HasActorBegunPlay c

[winged badger]

we use timestamps, and synced network clocks

so we can tell if the change happened recently, or half an hour ago

[chrome spear]

Ah okay, I just actually did that myself recently haha so that’s good to hear

I’m not sure if you’ve tested out level streaming or world partition in ue5 p2 but when level streaming is enabled, the client actor begin play happens before its onreps not after

So you don’t have any of your replicated variables in begin play

[winged badger]

all replicated variables are set, and all OnReps are called prior to BeginPlay

[chrome spear]

Not with level streaming enabled in p2

It’s bugged I think

[winged badger]

doesn't matter

[chrome spear]

Both are called in the same frame so onreps always come late

The values are all defaults and null

[winged badger]

PostNetInit is what calls BeginPlay on replicated Actors on clients

[chrome spear]

For static actors it doesn’t get called, it doesn’t seem

[winged badger]

and the initial replicated variables come in same package as instructions to spawn the replicated Actor, so one can't happen without the iother

static Actors are not spawned on clients

there is a difference

[chrome spear]

I’ve had to put in a time stamp to check if the onrep is directly after intialization

[hard hinge]

got like no idea why this is happening, been looking through the code but not finding anything useful sadly

[2022.04.02-00.33.54:519][136]LogSecurity: Warning: STEAMID:7777: Malformed_Packet: Received packet with 0's in last byte of packet
[2022.04.02-00.33.54:519][136]LogSecurity: Warning: STEAMID:7777: Closed: Connection closed

Anyone seen this before? All I'm doing is open steam.id_of_server and the server has this. My server is on linux.

[chrome spear]

Yes but the functionality changes between level streaming and a normal map. With world partition disabled it works as expected

Enable world partition and your onreps happen after begin play

[winged badger]

there is a bug i think

[chrome spear]

Yeah, I think so

[winged badger]

with streaming levels that are set to AlwaysVisible

basically, the visibility of the streaming level doesn't replicate correctly

[chrome spear]

So I’ve had to use time stamps just to check whether or not the onreps that occur within x time are first rep or not as it is

So I assume that’s fairly similar in concept to what you’re doing normally

[severe nymph]

@winged badger i've tried with it on and off

same behavior

I've also rebuilt it

LogBlueprintUserMessages: [BP_Ai_Male_C_0] Client 1: true
LogBlueprintUserMessages: [BP_Ai_Male_C_0] Server: false
LogBlueprintUserMessages: [BP_Ai_Male_C_0] Server: false
LogBlueprintUserMessages: [BP_Ai_Male_C_0] Client 1: true
LogBlueprintUserMessages: [BP_Ai_Male_C_0] Client 1: false
LogBlueprintUserMessages: [BP_Ai_Male_C_0] Server: false```

[winged badger]

not there

project settings navigation

[woven basin]

Is there an generally agreed approach for “instance” style dungeons in multiple open worlds? In single player I’d just load the player to another level/map. But is there a way to do this on a dedicated MP game?

[severe nymph]

@winged badger you talking about client side navigation?

[winged badger]

yes

[severe nymph]

of course you want this

its how sim proxies do movement prediction

[gleaming kite]

Is there a way to handle this while/before the game mode creates the pawn?

[severe nymph]

The thing is that with net load on client nav mesh disabled

and only a server copy of the ai

the client shouldn't be doing any CMC corrections on Server controlled AI

@winged badger

[gleaming kite]

From what I was told, no (without super complex networking code) In multiplayer sessions, the server only loads one map and all players have to be there. A good solution that most games do is to put the dungeon below the map and teleport players there

[severe nymph]

The server reps AI position out to clients

not the other way around

[woven basin]

Yeah, that’s what I assumed as well. Thanks

[gleaming kite]

Np

[dark edge]

That's literally what we're doing. Home is in a spaceship. Dungeon is on the ground.

[obsidian gyro]

I have a problem where The client can see the host's full head/gun rotation, but the host can't see the client's head/gun rotation, the clients bullets(which are shot from the rotation of its camera) are never able to shoot upward or downward because the host sees the clients head as not moving up or down, how do I fix this?

[dark edge]

What variable drives the look/aim rotation?

[winged badger]

if your server has NavMeshWalking set, and client either has normal Walking, or doesn't have a NavMesh, this is what happens

[obsidian gyro]

the character movement and this:

[winged badger]

Actor spawns on client on same position as on server (30ish UU above ground), next CMC Tick, the Actor starts falling on clients, as its in the air, as far as its local CMC is concerned

next server update correction happens, server update causes it to teleport it back on the navmesh

and it start falling again

movement updates from server don't arrive every Tick, and in between client CMC does its best guess, in this case best guess is that it should be falling

[dark edge]

So the ControlRotation is what's driving it. That isn't replicated to other clients. Try GetBaseAimRotation

[obsidian gyro]

im not sure how getbaseaimrotation would help here

[spark owl]

anyone know anything about overlap events on servers? they seem inconsistent

[obsidian gyro]

nevermind, I figured it out, tysm

[dark edge]

What's the scenario?

[spark owl]

basically anytime I have my overlap events use switch has authority to make sure that it's only the server that's firing them, it just seems inconsistent for when it detects the overlaps, it will work sometimes but sometimes it won't, i don't know if this is relevant but the hitboxes are attached to bones of a skeletal mesh so they're constantly moving with the animations of the player model

[dark edge]

I mean how fast?

Could be tunneling

[spark owl]

at times very fasst

it's a soccer game

[dark edge]

Turn on CCD

[spark owl]

CCD?

[dark edge]

continuous collision detection

[spark owl]

i think I did

there's also another issue I have

[dark edge]

make sure you turn it on for both bodies you need to collide

[spark owl]

where sometimes the overlaps will trigger when they shouldn't

yes that's not the issue

it's that it works sometimes but not others

this is an example of the issue where it triggers when it shouldn't

i've had this problem for a long time, been trying to find a fix

i just asked because I've just had a hard time with overlaps running on server

for example in this game there is a slide tackle mechanic

there are hitboxes attached to the players feet

if overlap only runs on server it doesn't fire usually

basically when the hitbox overlaps the ball it runs a custom event

[dark edge]

Move the overlap box for the goal back a bit.

[spark owl]

that gives it some impulse

[spark owl]

i did that, but that's a workaround

not a solution

i can't move it back that much

[dark edge]

It's probably a tick order thing.

basically it might be triggering overlaps 1 frame ahead of what's being rendered

how fast is the ball moving?

[spark owl]

fuckin fast at times

[dark edge]

Yeah i'd drill down and do some testing to make sure it's never physically ahead of where it's showing

is ball moved by Physics?

[spark owl]

yes

i was thinking the problem is something along what you said, where it's processing the overlap ahead of physics

[dark edge]

That smells like a tick order thing yeah

It's more that the physics is ahead of the rendering

[spark owl]

how can I mess with the tick order

[spark owl]

yeah that makes sense

[dark edge]

https://docs.unrealengine.com/4.27/en-US/ProgrammingAndScripting/ProgrammingWithCPP/UnrealArchitecture/Actors/Ticking/

Could be some physics settings you can tune though if this isn't it

[spark owl]

hmm ok i'll try this

[dark edge]

Make a testing setup that's less complex so you can rule things out

[spark owl]

good idea thanks

[severe nymph]

I’m still a bit lost to what you mean

The client cannot have different properties for a server spawned replicated proxy

It’s a server authority spawned character class

With its walking mode set to Nav mesh walking as “defaults”

The Nav mesh is generated on server “as the cmc is sending transforms”

And the nav mesh is net load on clients by default

If the character is placed in the level all is well

If it’s spawned by authority the client is falling spams

I’ve also debug printed walking mode with navmesh enum output on both the client/server

normal walking doesn't result in "isfalling" spams

navigation is on both client and server

[ashen stone]

Do anyone knows why this can happen? the pawns are detroyed on each other screen after some time

and EndPlay is called only on client with Reason = Destroyed

the Channel close reason is 170, strange

[ashen stone]

i fixed, it was relevancy problem ...

[obsidian gyro]

I have a problem where the client is constantly moving slower(and laggier) than the host is, they use the same player character

Is there anything that could be causing this?

[lavish minnow]

has anyone done any large scale multiplayer experiences hosted on AWS, of up to 80~100 clients. (previously we have done smaller scale ones hosted on our own servers supporting ~30 people). Is 100+ clients a feasible thing for the default networking system to handle?

[near bison]

What's the correct class to add all my UI to player for multiplayer games?

[kindred widget]

Do you mean like floating names above heads, or all on screen UI?

[near bison]

just a screen UI

idk why I'm struggling.
just 1 (same) button on all clients

[kindred widget]

Sounds like some form of state based replication that calls HUD and adds it. Really depends on the button, what it's for and why it needs to be shown.

[near bison]

It's a settings button

I jsut want it on my client when the client loads up

Why is this so hard? and no, I'm not going to replicate anything for this

UI should be local only.

[kindred widget]

Then your issue isn't a multiplayer one. Add a widget to screen from where ever you manage your UI. AHUD is usually a good place for this.

[near bison]

I mean it is a multiplayer one, but that's the next step. I was trying to add my entire UI in my playercontroller so far

AHUD? Do I need to create a new HUD class?

[lavish minnow]

Spawn the widget in your pawn or player controller on beganplay?

[near bison]

i tried that @lavish minnow . you can't spawn widget like that in player controller

[kindred widget]

AHUD is a local only class spawned by the player's local controller. It's a good place to keep UI, because it cannot network, but everything still has global access to it through the local controller. One AHUD instance per player, per machine.

[lavish minnow]

you mean you want the server to trigger the appearance of the widget?

[near bison]

I don't, and I never will do that @lavish minnow (at least until the need comes up)

[near bison]

this looks like what I'm looking for. Thanks

Is this ok or do I need to feed in OwningPlayer in the HUD class? does it implicitly resolve?

[kindred widget]

That's fine. Owning Player only matters with multiple players on same machine.

It'll run through the framework to find the local player for you and set it.

[silent valley]

Fortnite with 100 players is the usual example, that yes it's possible. It all comes down to optimization. Replication Graph will be important to hit that number for sure.

[near bison]

how to get player state in HUD class

[twin juniper]

Get a class that holds a PS reference and get it from it

so PlayerController, Pawn

etc

[near bison]

does player controller implicitly get the local playter controller?

[twin juniper]

you could just get the owner

HUD Owner is always the player controller

i guess it's referenced in PlayerOwner

[near bison]

ok great.
now, I am trying to print something from local player state in my HUD. however, it does not give me the correct result. Basically, I get only one of my connected clients printing

Lol ok...looks like it's because PlayerState is not set on time

[kindred widget]

Playerstate requires time to replicate. If you have C++ access, it can be good to drop some delegates in GameState on the Add/RemovePlayerState functions.

[near bison]

I'm using Blueprints only

Can I not have an event on PlayerState?

But is the problem that I can't bind to that event because playerstate is not available in the first place?

This isn't gonna work is it

[kindred widget]

PlayerState Beginplay could, probably. Make a GameState delegate and have your PlayerState call it with passing Self through it.

Beginplay will never run on any system before a GameState is valid. So GameState is a great place to keep your core UI bindings that you have to rely on a replication chain for.

[twin juniper]

or you have OnRep_PlayerState

on Pawn/Controller

[twin juniper]

idk if you can override this on BP tho

[near bison]

I don't see an OnReP_PlayerState in my pawn

[twin juniper]

C++ 😛

[kindred widget]

There is pretty much no BP access to the core framework stuff. Easy to override in C++, but BP only requires a little bit of workaround.

[near bison]

guys

please help me find an equivalent solution in BP, I'll be ever so grateful

I think this is the only problem I'll encounter in BP, starting state and setting up with UI

everything else is predictable/workable

[twin juniper]

Delay(10 minutes)

[kindred widget]

^

[near bison]

I have an event dispatcher in my playerstate that I call on beginplay

[kindred widget]

GameStateDelegates, Make two. PlayerStateAdded, PlayerStateRemoved, Call them in PlayerState's Beginplay and Destroyed events.

[near bison]

but how can I bind to that in my AHUD class? Because I don't know at that point the PlayerState right? The cast will fail

[kindred widget]

Game State. Not Player State

[near bison]

is gamestate available from the get go?

[kindred widget]

^

[near bison]

missed that, nice

[twin juniper]

just curious but what are u trying to access on your PS ? 😄

[near bison]

TurnNumber

if it's the current player's turn, then show UI elements

[twin juniper]

why u holding that on PS, it needs to be persistent across levels ?

[near bison]

no, just 1

the main level

[twin juniper]

then you can just hold it in your PC

[kindred widget]

No.

[near bison]

but why? i want my turnnumber to be replicated

[kindred widget]

Array of PlayerStates in the GameState.

[twin juniper]

?

You can replicate things in your PC

Pawn

etc

etc

[near bison]

why not playerstate?

[twin juniper]

You use player state for things that needs to stay across levels

[near bison]

does it matter though?

[kindred widget]

Depends on the game. If it's all players, I'd just drop an array of playerstates in GameState.

[near bison]

dont I already have access to array of player states in gamestate, GetPlayerArray

[kindred widget]

PlayerState is also used for player relevent data that all players need to know about that doesn't belong on Pawn.

I meant an ordered array in the order of your turns.

[twin juniper]

would not use PS at all if its for all players, if it's Turn Numbers like the Round Count or smth just GameState is sufficient

[twin juniper]

yeah but for it's UI Stuff actually so it's more an PC stuff

than Pawn or PS

[kindred widget]

Player Controller really has no business holding anything UI related most of the time.

[twin juniper]

He's literally talking about an HUD Class

that is holded by the PC ?

so ?

[kindred widget]

Well lets just fucking network all UI through the GameMode then. It spawns the GameState.

[twin juniper]

Or just using things as they should be used

👍

[near bison]

nah, all UI stuff should be client only

ok guys I hav a good solution. works fine for now.
hear me out:

[kindred widget]

PlayerController is a networking and input handling class. It has no business messing with UI.

[twin juniper]

that's exactly what i said

[twin juniper]

we can say the same for PlayerState

GameState

etc

[near bison]

in game state I call an event when all player states are ready.
I bind to this event in my HUD class. BOOM. works like a charm.

magic

[kindred widget]

PlayerState is a class meant to hold data per player. GameState is a class meant to hold data about the game.

[twin juniper]

persistent/relevant data

but yeah ok

anyways 👍

i don't see at any point why you would need to hold a non-persistent UI data on player state, it does not even need to be relevant but anyway

[kindred widget]

Out of curiosity. Where would you store a player's current level's score that doesn't move to the next level?

[twin juniper]

PC

[kindred widget]

And how are you planning on letting Player 2 know what Player 3's score is?

[near bison]

bad idea

[twin juniper]

ShooterGame does it

UT4 does it

[near bison]

btw. @kindred widget
This is the most useful statement I have ever come across on this channel:
"Beginplay will never run on any system before a GameState is valid. So GameState is a great place to keep your core UI bindings that you have to rely on a replication chain for."
I can literally bind whatever events I want via this

[twin juniper]

that's not because your "Blueprint Tutorial Series" on youtube told u to put everything related to your player on PS that this is a good thing

[near bison]

mmm, but how to replicate those. are you gonna replicate the variable itself

[near bison]

I come from a Unity background building mp games with 2+ years experience.
Tbf all these seem like unnecessary abstractions to me lol

[twin juniper]

was not talking to u tho

[kindred widget]

You still haven't answered the question. How are you going to tell Player 2 what Player 3's score is?

[near bison]

yeah i get it i get it, just saying that i dont like what unreal has done with all of these abstractions.
didn't they prune GameMode and GameState to GameModeBase and GameStatebase. We need more like that

[chrome spear]

ShooterGame stores kills and deaths on the playerstate, the gamemode or gamestate then iterates through all of them on match end to generate a score

it's not on the pc, there's some variables on it for internal tracking i think

[near bison]

btw if I ever have bots, will they also be using playerstate?

[kindred widget]

If their set to request them.

[pallid mesa]

you can yes

[kindred widget]

PlayerState has a IsBot function you can call to test if it's a player or AI

[near bison]

ok. Right now I am hardcoding playerstate.length == ExpectedPlayerCount. If I have bots I want that to add to playerstate too

[chrome spear]

and there's a setting, I think in the ai controller to make it have its own player state

[pallid mesa]

specially if you want them to have score/name

it's handy

[near bison]

guys, I fixed blueprints for multiplayer with this one sequence. do I call tim

I can bind whatever events I want now anywhere because I have my playerstates ready

wow

[pallid mesa]

that's indeed Timothy

[near bison]

this should be out of the box in BP. I think it is for C++

I. need. more. events. to. bind. to!

[pallid mesa]

theorically using Jambax idea you get rid of this problem

specially since it's a subsystem that you'll be able to access everywhere

doing it blueprintable won't be much effort

it just requires some C++ here and there + the subsystem

[near bison]

it's fine. i don't think i'll have the problem anymore with the above setup ^

I'm just gonna safely wait for all clients to connect and their playerstates be ready before I do anything in game

just gonna add a "Waiting for all clients to connect..." UI before the event fires

ez. why complicate anything

[pallid mesa]

😄

[near bison]

anyway blueprints for mp sucks. not gonna reinvent the wheel XD

btw just out of curiosity, if a client disconnects and reconnects, his state is taken care of right? (if all the needed vars are replicated?)
How is this handled

[pallid mesa]

when a client disconnect their player state stays around for some time

so indeed you can support reonnections i believe implementing OverrideWith

but not sure to what extent that exists in BP's 😅

[near bison]

i'm losing hope

can I not build a production ready game iwth BP

I'll probably tackle this when we get there

hopefully isn't too hard

[twin juniper]

you cant in fact, just with a few workarounds 😄

but i would still use cpp if i was u 😛 (when u got time. don't abandon your current project to learn cpp)

so you can explore the engine source code and understand how things does this and that out of the box !

[hallow summit]

How do I wait to spawn players till all clients are loaded in to the level?

[bleak cargo]

C++ only multiplayer hud.
Hello, I wonder if it is possible to set multiplayer inventory (I have one variable containing pickuped items) and own HUD for all the clients without adding a lot of extra classes (atm all logic - interwaction, hud is in Character class).
When there is one person on the server its working just fine, but when its 2+ -> everyone share the same hud (i have hud prompt for interaction and when one person wants to open the door everyone have this prompt) and when i try to pickup item item is picked up but nobody have it.
All tutorials that I was able to find use BP for this logic ;-;
I really dont want to change much the logic i already have ;/
I would really appreciate it if somebody could answer me some question on pm

[fathom aspen]

AController::InitPlayerState is the function that spawns and initializes a PlayerState for the Controller. It's virtual so you that's probably what you're looking for.
Also it happens before there is a pawn spawned and possessed.

[near bison]

Is there an event I can listen to on the server after a variable has replicated to all clients successfully?

[bitter oriole]

There is no way to know that, unless you add a server event on client that fires when a particular variable replicates

[near bison]

Can I do something like this? @bitter oriole

So in repvar, once it successfully replicates, (on the local player) call an event

[bitter oriole]

Yes, if you really need that

[near bison]

@bitter oriole may I walk you through my use case, you can suggest your best approach after listening to mine

[bitter oriole]

I guess

[hallow summit]

Is there a way to wait for all clients to load level before beginning play?

[bitter oriole]

No, but you can have each client send a "I am ready" event to the server that calls a "real begin play" event once everyone is there

[near bison]

@bitter oriole

• in GameState, wait for all clients to load (by checking length of PlayerArray),
• Function to set turn order of all players (this is a board game),
• In function, get all PlayerStates, set a RepNotify'd var called TurnNumber,
• In TurnNumber repNotify (on player state), enable my UI on HUD

[bitter oriole]

Okay, sounds good

[near bison]

That's it..works most of the time, but got this error once
Blueprint Runtime Error: "Accessed None trying to read property GameState". Blueprint: KTHUD Function: Check if My Turn Graph: CheckIfMyTurn Node: Return Node

I'm setting the GameState way before calling this function though

[bitter oriole]

You can only call server events on player controller, player state, possessed pawns, and objects they own

[near bison]

But HUD does not exist on Server right? I'm calling this from HUD

[bitter oriole]

Obviously HUD cannot have server events

[hallow summit]

How would you tell when the client is “ready”?

[bitter oriole]

But neither can game state

[bitter oriole]

Depends on your game

[near bison]

@bitter oriole can I not bind to a GameState event from HUD?

[bitter oriole]

You can only call server events on player controller, player state, possessed pawns, and objects they own

Other objects cannot have server events

Dunno if that's your issue here

[near bison]

No it isn't, I can still bind to events on Game State in my HUD. GameState is replicated

[bitter oriole]

Okay, but consider this: You cannot have a Server event in GameState

Just checking if you tried doing that

[near bison]

What are you talking about though? The event I'm listening to is client sided

i.e GameState pushes out an event on multicast for all clients to listen to

[bitter oriole]

Okay then, so it just sounds like your KTHUD is reading game state before it replicates, then

[near bison]

I suspect this too

Do I need an event dispatcher for when game state is ready? :/

Does HUD load first?

[bitter oriole]

There is never any guarantee on timing

You can poll it on Tick, or use another event

[near bison]

Looks like I'll have to use an event, sigh

hahahah but the question is, how do I even listen on that event if the GameState doesn't exist yet?

lol

Where can I reliably acccess GameState without race conditions again?

If Pawn exists does that mean for sure that GameState exists?

[bitter oriole]

Tick, get game state, is valid

[near bison]

Delay better. I think

[bitter oriole]

Why would it be better?

[near bison]

tick on every frame 😦

[bitter oriole]

Being afraid of Tick is a disease

[near bison]

Yes but I have to bind to a function after. I wouldn't wanna do that in Tick right?

[bitter oriole]

You could do the binding and then disable Tick

[near bison]

I'm calling Delay right now in BeginPlay, so that the handlers don't get registerd again later

Why disable tick though? What if I need it for later

[bitter oriole]

Delay is almost never a good solution

[near bison]

why?

Disabling tick sounds worse to me

What if I want it for something

Also how do I disable*** tick?

[bitter oriole]

i'm assuming you only need to bind your listener once, and that you don't currently use Tick, so in this context I'm suggesting something like "wait on tick for a valid game state, bind your stuff to it and then either check if you're bound alreayd, or disable tick"

Delay in multiplayer is terrible because you're assuming a given time is going to be enough

[near bison]

Yes but I'm putting delay on loop

🙂

[bitter oriole]

Just use tick

[near bison]

I am very averse to using Tick, sorry.

And this will work fine

My problem is not here anyway

[bitter oriole]

Like I said, this stuff is a disease

[near bison]

nah

tick leads to more problems the way I see it, I don't wanna accidentally keep registering listeners and then having memory leaks

I've had it happen before

Having any logic to register an event listener frame per frame is a bad solution

Even if there are checks in place

[bitter oriole]

Right now you literally have a tick that ticks only 10% of the time

So I'm not sure how you think it's somehow different

[near bison]

because it safeguards me against memory leaks

[bitter oriole]

You literally can't leak memory in Unreal

Even in C++ it takes some serious stupidity

Anyway, not my code, not my problem

[near bison]

it doesn't matter anyway

tick 10% of the time doesn't sound too bad 🙂

Do I have access to the variable that just changed in OnRep?

[kindred widget]

The value will be changed before the OnRep is called. I don't think BP has the ability to pass in the old value.

[near bison]

So bad.

Can you help me solve my problem if I quickly mention my use case?

• in GameState, wait for all clients to load (by checking length of PlayerArray),
• Function to set turn order of all players (this is a board game),
• In said function, get all PlayerStates, set a RepNotify'd var called TurnNumber,
• In TurnNumber repNotify (on player state), enable my UI on HUD

[bitter oriole]

You haven't explained what the problem is in those four statements

[near bison]

I can't do the last step

[dusky yoke]

Do you guys have any tips on what to troubleshoot if I'm trying to host my game with Advanced Sessions Steam API, and my friends can't see the server? When they host on the other hand it's fine. They're both situated in Netherlands, not sure if that has anything to do with it, but yeah

I've tried disabling my firewall and exiting my editor while testing

[kindred widget]

First off. Start by putting the function in GameMode. GameState should never have this logic as it's a server authoritive thing. GameState's functions should be things that even clients can call, maybe filtering functions for game state's data, etc.

Regardless of the upper point. You'd need two OnRep for this to be solid. One OnRep for the Player's Turn, and an OnRep for the GameState's CurrentTurn. Both should call HUD, or have bindings that a widget or HUD can use to show/hide things based on if CurrentTurn from GameState == Turn from the PlayerState

[near bison]

@kindred widget

You mentioned this right? Does this apply for ALL begin plays? Including HUDs, playerstates etc?

[kindred widget]

Every single Beginplay applies to this. GameState sets a value in the current World. The World holds whether it is ready for beginplay. When GameState starts up, it will get all current actors in the world and broadcast Beginplay to them. Or more accurately I think it has World do this, and then World sets it's HasBegunPlay value to true and from then on every time World spawns an actor, it calls BeginPlay on it directly after it's done spawning.

[near bison]

Including HUD right?

[kindred widget]

Every Actor

[near bison]

HUD is not an actor though right?

[kindred widget]

AHUD, it's an Actor spawned by the Player Controller locally for the client.

[near bison]

ok thank god

[kindred widget]

People name some of their widgets Hud. Not to be confused with AHUD which is an actor.

[near bison]

So is this the right one? (The one that waits for GameState)?

[kindred widget]

Yep. Blueprint.. very stupidly removes class prefixes. Mildly annoying.

[near bison]

Next question: how do I check and bind events/do whatever I want ONLY on my local client in any of these networked blueprints?

For example HUD, print "Hello" ONLY on my local client?

[kindred widget]

That is a very easy and a very hard question to answer at the same time.

HUD for instance is local only. It has no networking. If you get HUD on a machine, it belongs to that machine and has no version on another machine.

[near bison]

Then why is my "Hello" printing on all clients?
Client 1: hello
Client 2: hello
Client 3: hello

is that an Unreal thing? Showing logs of all clients on 1 client's screen/

[kindred widget]

What event did you print Hello on?

[near bison]

BeginPlay

I guess, cause it runs on all clients right

[kindred widget]

It's more of a PIE thing. Prints run on all viewports. What you're seeing is each client printing once.

[near bison]

But how is it printing on all clients if HUD is only on 1 client

[kindred widget]

HUD is on every client. One per client, non replicated

One AHUD per player, per machine.

[near bison]

so in this case, how do I get only the HUD belonging to me? and not the others? in OnBeginPlay?

[kindred widget]

A Dedicated server has no players, and has no HUD. A Coop game with three people has one machine, but still has three HUDs

This is what I meant by easy but difficult to explain. 😄

[near bison]

No I got what you're saying, the other 2 connected players have Actors spawned on my local machine

[kindred widget]

No, not in your case.

You're misunderstanding the prints in this case.

For example, put a print in your Pawn's beginplay.

If you have 3 clients on a Listenserver, you'll see 9 prints.

AHUD will have 3 prints, Player Controller will have 6 prints

You're seeing a print from every version on every machine when testing in PIE.

[near bison]

using dedicated, not listenserver

So why did Pawn print 9 with 3 clients? Shouldn't it print only thrice because pawn is locally owned only?

[kindred widget]

In that case, you'll see 12 prints for Pawn, Still 6 for Player Controller and 3 for HUD

Like I said, you're seeing a print for every version of that actor on every machine you're simulating.

When you have 3 players, every machine has to have a version of that Pawn. So...
Server, Client1, Client 2, Client3, all have a version of Client 1's Pawn.
Server, Client1, Client 2, Client3, all have a version of Client 2's Pawn.
Server, Client1, Client 2, Client3, all have a version of Client 3's Pawn.
12 prints

[near bison]

But I thought Pawn is something that's only locally owned, Why would BeginPlay print for Client2 and Client 3 on Client1's machine?

[kindred widget]

Beginplay runs on every machine the actor exists on.

[near bison]

Ok so just to be clear, when there are other players in game, their objects are also considered Actors, in essence

Do I have that right?

[near bison]

ok. this I'm aware

[kindred widget]

Pawn is a class that can be possessed by a PlayerController for input.

Usually a Character in Unreal games.

[near bison]

Ok so, 6 for playerController because:
Server, Client1, all have a version of Client 1's Controller.
Server, Client 2 all have a version of Client 2's Controller.
Server, Client3 all have a version of Client 3's Controller.

[kindred widget]

Correct, cause other clients do not have a version of other client's controllers.

[near bison]

Fantastic

Ok so, 3 for HUD because:
Client1, all have a version of Client 1's HUD.
Client 2 all have a version of Client 2's HUD.
Client3 all have a version of Client 3's HUD.

[kindred widget]

Yep.

[near bison]

So now I'm confident that my event handler in HUD is being bound only once, even though it's in BeginPlay. so that's good.

[kindred widget]

If you're ever in doubt, test by disabling the RunUnderOneProcess setting. It'll make clients run in Standalone mode.

[near bison]

Let's tackle the next problem, if you don't mind

[kindred widget]

Prints are process specific and PIE simulates all machines under one process so to speak. So in PIE, client 1 can see Client 2's prints, etc. In Standalone, it separates that out.

[near bison]

If we solve this I'll get a very good grasp of what to do to avoid these nasty race conditions

So now, in my GameState, I am looping through all PlayerStates and setting their Turn Number

When I know my turn on my local client, that's where I decide whether to enable or disable their own HUD.

So naturally for ease of use sake, I want to hook into OnRep of TurnNumber in PlayerState so that I don't have race conditions

[kindred widget]

Personally. Like I said before I would just drop a delegate in the GameState for OnCurrentTurnChanged, and one in the PlayerState for OnPlayerTurnSet.

Make Set functions for your Turn variables in both classes and call these delegates after setting the value.

Have a function in AHUD that GetGameState->GetCurrentTurnNumer == GetLocalPlayerState->GetPlayerTurn. If this is true, show your widgets, if this is false then hide your widgets.

Have HUD's Beginplay GetGameState, and GetLocalPlayerState, and bind those two delegates and then also call the function you made that does the check.

Now, regardless of what happens in whatever order, your HUD will set things to display correctly.

[near bison]

So, the OnRep_CurrentTurn works fine, because there are no race conditions well into the game.

I'm looking into what you said with OnPlayerTurnSet

Already have the function you mentioned in my HUD

Now my problem actually lies in this part:
Have HUD's Beginplay GetGameState, and GetLocalPlayerState

What if I don't have the LocalPlayerState in my HUD begin??

[kindred widget]

Same thing. You bind to the GameState's PlayerStateReplicated thing.

[near bison]

Like this?
This is in GameState

And then I bind to AllPlayerStatesReady in HUD

[kindred widget]

Maybe. Personally, if this was me, I would make a throw away widget for it. Initialization is fucking annoying. You know that Local PlayerState will arrive at some point. I would just plaster a widget up that says "Waiting for game to start", or whatever. Tick whether the game is ready. Then make a call to whatever to bind your delegates. Once that's done, you can throw this widget away, which will stop it's tick.

[near bison]

Should I use a delay instead of Tick?

[kindred widget]

Same thing in the end.

[near bison]

Ok so now my flow is:
When all player states ready, I get local player state in HUD and set it in a var

[kindred widget]

Blah blah, delay is probably faster cause bp tick, something something performance, cause doing stuff the hard way is better, use timers, cause they're so much neater, etc etc. I'd just tick it. They're very simple fast checks that not even a phone would recognize in BP.

[near bison]

But the problem is: now has my TurnNumber finished replicating or not?

Now you want me to have another delegate in PlayerState correct?

[kindred widget]

Doesn't matter if the turn number has replicated or not. That's why you both bind and call the update function.

Only thing that matters as far as initialization is that you have a valid GameState, and LocalPlayerState on that client that you can bind things to.

After that, replication will take care of the rest just from calling that function post binding and on each binding.

[near bison]

I can guarantee this, all good. I think both exist now for sure.

Actually, wait what? I tried playing like 10 times. Like 3 times local player state wasn't there

Guess I have to do this then? lol

[pallid mesa]

@near bison initialization code pursues you

🤣

[near bison]

hahahah

[pallid mesa]

told you

[near bison]

it's ok, this ^ of mine works all the time

Just delay until player state is available locally.

Working 100% of the time.

Done.

Now what's the final step?

How do I hook into when TurnNumber is correctly replicated on my client?

[pallid mesa]

onrep

[kindred widget]

Try this out. It's a fairly simple setup.

[near bison]

Yep, I've done all of this.

[kindred widget]

This should be all you need in HUD. Replace the prints with calls to show or hide the HUD.

[near bison]

Question is ,when do you Call OnPlayerTurnSet in PlayerState?

How do you know when the PlayerTurn has successfully replicated?

[kindred widget]

The OnRep.

Default Value for turns should probably be set to something you'll never use for turn number, like -1.

[near bison]

Done done

[near bison]

So I think what's happening now is:

(since it isn't working)

My OnRep fires the call BEFORE my player state is bound in HUD i presume?

Yep I can confirm that's what's happening @kindred widget

[kindred widget]

Which is fine.

Sometimes it won't. That's why you call the update function after the binding calls. No matter what happens, at some point in time, something will update this to the correct state.

[near bison]

No but my button isn't appearing. So clearly the order matters doesn't it?

Which update function?

[kindred widget]

Second part of the sequence

If you set this up like these images, and cannot see the button, then for some reason your client has been told it has a different turn number than the current game's turn number

[near bison]

Yeah I missed the second part of your sequence

Implementing it now

lol this...is so weird

I am calling SetLocalPlayerState() (to a local variable) and THEN in the second sequence calling UpdatePlayerUI for turn

Why is the function saying the localplayerstate is invalid???

Does sequence not run...sequentially?

[spark owl]

so I have collision hitboxes attached to different bones of a skeletal mesh, I'm wanting these collision boxes to trigger overlap events, the problem is that it seems like the hitboxes do not move with the skeletal mesh on the server, so when I have the overlap events run only on the server, it doesn't work as it should, it's like the hitboxes don't move with the animations even tho they are attached to the skeletal mesh. Does this make sense to anyone? This is the conclusion I came to but i'm not sure if it's right

i wonder if there's a way I can make the server factor in the movement of the animations so the hitbox moves accordingly

[pseudo merlin]

Anyone have thoughts on a good time to write client persistent stats to disc on a multiplayer game? The most obvious route I think is on round end, but if that leads to map change there could be instances where client is still writing on map change. Do servers wait for all clients to confirm they are done writing?

[chrome bay]

Well if you're storing it client side it doesn't matter right?

[pseudo merlin]

But if server calls change map, and client is still writing to disc async, there may be some risk there?

[bleak cargo]

Destructible Object on Multiplayer.
Anyone know how to delete an item after is destroyed? I need solution for LATE JOINING into the game, every new player can see this object and interact with it. I have no issue with other object such as bullets or pickup items when client late join. But i cant hide/destroy permanently Destructible Object ( even GetWorld()-> DestroyActor(this) do not work)

[chrome bay]

Wouldn't have thought so, if it's a just a single RPC that says "pls write this to disk". Users can change maps while writing to the disk.

[pseudo merlin]

Ok cool! Thanks

[chrome bay]

You'll need the actor to be replicated in order to destroy it

[oblique flicker]

Hi guys! I have a small problem and I'm kinda stuck. I'm trying to automatically change the map when the round is over. Server side running on a dedicated server(so the host,player, can change the map). I've seen some docs about travel and seamless, but I saw that you can change one map, not more. I have multiple maps for 1 gamemode. Right now I'm using reset game. Thank you!

[chrome bay]

Just use the ServerTravel feature to move to the new map

And be sure to enable seamless travel

[oblique flicker]

I know that, but after the next map is changed, the round will be over on that map and then I need another map. That's why I'm asking. I have 7 maps for that gamemode

[severe nymph]

@winged badger btw

Disabling client navigation fixes the issue

But the issue is I need this for ai auth only spawned characters

[winged badger]

that just sounds... wrong

we have client side navmeshes and autonomous proxy predicted movement with pathfinding

[severe nymph]

https://media.discordapp.net/attachments/322374743007297537/959854762961043506/unknown.png

[winged badger]

we had that jitter issue, but only because CMC on clients started in wrong movement mode

[severe nymph]

Easy mock-up

Blank thirdperson template

Slap in map

Set navmesh walking on the aibase

Project settings “client navigation”

Toggle it on and clients will print “falling”

In animbp

Be sure to enable ai controller possession for placed and spawned in world

Test “as client”

[chrome bay]

The mode will reset when you change maps

Or at least, the MatchState will change. You may need to handle your custom logic in the various overridable functions in the GameMode class, though I'm not sure how many of them are exposed to BP.

[severe nymph]

@winged badger I use client navigation for teleport btw

For vr players

[mortal kernel]

How can I make sure things that are being executed in repnotify also work in singleplayer? Should I just set it or is there some cool trick I don't know of?

[severe nymph]

So disabling at project level isn’t an option

Need to find out why navmesh walking on server spawned AI is doing this

Shouldn’t have to use “walking”

[oblique flicker]

Yes, but it’s the same mode for every map.

[chrome bay]

That's fine, I use the same mode for my maps also

[winged badger]

did you even try to manually set NavMeshWalking on CMC on BeginPlay for that AI?

[severe nymph]

@winged badger I'm printing it out

[mortal kernel]

Btw just wondering do Player Controller Begin Play fire on map travel with seamless travel enabled?

[winged badger]

that means no

[chrome bay]

Should do yeah

[winged badger]

BeginPlay -> GetMovementComponent -> SetMovementMode (NavWalking) and reenable client nav

[mortal kernel]

Some people told me it wouldn't because they are brought into the new world as is

[severe nymph]

LogBlueprintUserMessages: [BP_AIBase_C_0] Client 1: Navmesh Walking```

@winged badger

[winged badger]

which is not even remotely the same as printing out DefaultLandMovementMode

[severe nymph]

what?

the base class CMC component default is nav mesh walking

[winged badger]

DefaultLandMovement mode is not MovementMode

so do what i told you, exactly

[severe nymph]

wtf

[chrome bay]

Hmm I could be wrong actually, I don't use BeginPlay much tbh

Have to give it a try

[severe nymph]

the "movement mode" is ignored on clients when spawned from the server?

really?

[winged badger]

they will always call BeginPlay if class has changed

[faint eagle]

is CMC's saved move expected to be replicated to other clients? for some reason I can see sprinting animation only on owning client and on server but not on other clients

[mortal kernel]

I can't test rn but let me know if you figure anything out :o

[severe nymph]

server spawns them as "navmesh walking" for "movement mode" server and client prints navmesh walking as "class defaults"

but client still loads as walking

thats retarded

[winged badger]

its not, thats just between autonomous proxu and server

[winged badger]

welcome to unreal, its full of landmines

[severe nymph]

thanks bud

i really appreciate it

beating my head against a wall on this

[faint eagle]

so do I have to replicate the bSprinting variable by myself with UPROPERTY(replicated) then or is there anything else to do with FSavedMove to replicate it to simulated proxies as well?

[winged badger]

they just need the speed, really

acceleration if you're using it, but yeah

[faint eagle]

well in my case sprinting variable is used in anim BP so i need that variable

[winged badger]

just don't try to replicate it inside the anim BP 😄

[faint eagle]

it won't work at all as far as i know

[bleak cargo]

but i can destroy it, i use the same logic as with pickup item. Just for some reason when i late join with new client only destructible object is re-spawned ;-;

[winged badger]

how is it spawned?

[bleak cargo]

its on the scene from the beginning of the game, i can destroy it and every client (that is at this moment in the game) can see its destroyed and fading away

but when i late join, new client can see and interact with it

[winged badger]

in that case ULevel should handle the destruction

[severe nymph]

damnit

ignore that

didn't fix

[winged badger]

/**
 * Stored information about replicated static/placed actors that have been destroyed in a level.
 * This information is cached in ULevel so that any net drivers that are created after these actors
 * are destroyed can access this info and correctly replicate the destruction to their clients.
 */
USTRUCT()
struct FReplicatedStaticActorDestructionInfo
{
    GENERATED_BODY()

    FName PathName;
    FString FullName;
    FVector    DestroyedPosition;
    TWeakObjectPtr<UObject> ObjOuter;
    UPROPERTY()
    UClass* ObjClass = nullptr;
};

    UPROPERTY(Transient)
    TArray<FReplicatedStaticActorDestructionInfo> DestroyedReplicatedStaticActors;```

[winged badger]

so im thinking you did something unspeakable there @bleak cargo

[bleak cargo]

maybe, cuz its my first time using UE4, and its hard to find any tutorials in c++ only for multi

making single was pretty ok, but with multiplayer, everything gets super messy...

[severe nymph]

@winged badger I even tried setting in constructor

[winged badger]

did you turn client navmesh back on?

[severe nymph]

yes

[winged badger]

@bleak cargo so its part of the level - static Actor, and you're destroying it with destroy, you don't do TearOff, you don't turn its replication off? Is it replicated?

[severe nymph]

they be jumping 😛

[winged badger]

i can't see any of that, nor do i have any idea what that print is

[severe nymph]

its sooo funny to see them hopping around 🤣

the print is "cmc is falling"

spamming between true/false

[bleak cargo]

THANK YOU! I found the issue! i forgot to check one option in the BP

[severe nymph]

LogBlueprintUserMessages: [BP_AIBase_C_2] Client 1: Navmesh Walking
LogBlueprintUserMessages: [BP_AIBase_C_2] Client 2: Navmesh Walking
LogBlueprintUserMessages: [BP_AIBase_C_2] Client 3: Navmesh Walking```

[winged badger]

are they jumping or jittering?

[severe nymph]

yup

[winged badger]

its an or question 😛

#multiplayer message no pawns here are walking on navmesh

[severe nymph]

huh?

[winged badger]

their feet should ne on the green plane, not the floor

[severe nymph]

your just telling me something I already know

lol

they are "falling" or "jumping"

and they will never "walk on" the green mesh

they approximate the floor

it works correctly with client navigation off

if the server is the "only thing" nav walking

[winged badger]

youre not giving me much useful information here

[severe nymph]

I've given you a complete mockup

prints of all logic

[winged badger]

video

[severe nymph]

1 sec and I'll zip the dang thing up

[winged badger]

i w9ont download or open it

[severe nymph]

you want me to record and upload the video here?

or you want me to jump in a chat

[winged badger]

video here

[severe nymph]

https://www.dropbox.com/s/tucol1pl88gdvf8/navwalking.mkv?dl=0

@winged badger

[winged badger]

well, one bit of good news is you can't use NavWalking for VR

it would look silly

[severe nymph]

what?

[winged badger]

you can pathfind with normal walking

[severe nymph]

you need client side nav mesh to get "navigatable radius"

[winged badger]

NavWalking is more performant, but they walk in the air

[severe nymph]

I'm not going to rpc to the server for that

[winged badger]

30cm off the floot

which can pass with isometric or top down camera

[severe nymph]

I draw and trace the arc with client side logic

[winged badger]

but not for FPS, TPS or VR

[severe nymph]

look

I've been doing this a very long time

I appreciate you trying to help

but your wasting my time

have a good day

[winged badger]

i don't know how to debug this with blueprints

c++ data breakpoint on MovementMode

[severe nymph]

I'm not blueprints only

i'm cpp also

[winged badger]

callstack to see what causes the change

[severe nymph]

again I'm a senior unreal dev I have access to source and can look there too

I simply posted the video to appease you

because i felt you were calling me a liar

[winged badger]

you did give me distinct blueprint only impression

[severe nymph]

again ... have a good day

you assume

[winged badger]

c++, data breakpoint the movement mode, examine callstack

[severe nymph]

which is offensive

assumptions are for "a-holes"

ever hear that?

if you check out my git you'll see I'm not simply a blueprint warrior

but its cool

again... thanks for "trying"

my point was "this is whats happening" and instead of looking at what was presented you "made assumptions" you knew better

"I have projects .... thats impossible... that seems wrong"

etc

your ego dude

[winged badger]

your animation blueprint is throwing conclusions off

[severe nymph]

check it

[winged badger]

can't see if they are actually jumping or jittering

which is an important distinction here

[severe nymph]

the animbp is default vanilla

and in the video anyone with eyes can see them in the jump loop