multiplayer

[winged badger]

if you can access the playerstate from PlayerController and print a correct PlayerName from PostLogin event

it will just work out of the box

[valid imp]

My actor on the server, let's call him Server Georges, calls a client RPC on a Player controller. Is there a way I can pass a reference in that RPC so that the Player controller will be able to do something on Client Georges?

[celest bough]

il give it a try now

ty

[fathom aspen]

If the reference is an actor, then it has to be replicated

[valid imp]

That's fine, I just want to be able to call something like DoThis(&TheActor) from server to the client player controller and the client will find the right actor (but on client side) if it does TheActor->Whatever() .

[celest bough]

@winged badger seems like the name was auto given to the player state which is handy 🙂

so i can just use that

thanks

[fathom aspen]

That's what happens, it's the replicated version actor. That's why I said you have to replicate as it's resolved into a GUID

[valid imp]

Perfect, thank you.

[winged badger]

and that means that every playerstate on every machine will know that name at the time it calls BeginPlay

which is also appropriate time for player joined message

[quiet fjord]

guys how is the command of server travel

for travel my clients with the server

[fathom aspen]

ServerTravel <MapName>?<OptionsString>

Well the ? is part of the options string but you get the drill

[quiet fjord]

ok i got it thanks

I am doing a custom matchMaking

[umbral horizon]

anyone?

[fathom glacier]

guys, I need some help. I'm creating a multiplayer dogfight project and I'm having issues with projectile. The server spawns projectile just fine, but the client spawns it with some serious offset when I'm not facing north or south. How can I fix this?

here is when I'm facing directly north

here is when I look slightly to the side

The server side doesn't have this issue

it gets worse whenever I look more to the side

[south crest]

why would OnComponentBeginOverlap be called on every client, when that component is not set to Replicate? (i do have actor replication turned on)

[limber gyro]

guys i have a character select system that works fine when u connect through IP but breaks when i connect though sessions, has any 1 has any similar issues? maybe because in testing im using the same steam ID it assumes the player controller is the same?

My characte select UI goes to the first player connected instead of the proper player

and if the first player picks a characte he swaps character again

[sinful tree]

If you've added the component to the actor in the editor (not at runtime) then that component still will exist on the clients, even if it is spawned by the server.

[south crest]

ahh i think it makes sense now

since all clients are tracking the pawn locations, the pawn hits the collider on all clients

[sinful tree]

Correct.

[fathom aspen]

Yeah that could be it. You can debug and see what the NetId anyways

[livid arrow]

what does setting an event as reliable do?

[sinful tree]

Unreal will keep sending it until the other side sends confirmation it was received. Should only be used for critical gameplay events, but not stuff that is rapidly sent (like a position of some kind on tick) or superfluous to the actual gameplay itself. Events not marked reliable are not guaranteed to be received by the other end.

[vivid prawn]

I'm trying to use Level Instance within the map (not Level streaming) and blueprints within it, doesn't replicated with clients, is this a known issue or am i missing something?

everything work perfectly on Server side, but not client side

basically nothing show on client side

well the blueprint init all showing up on client side, but not the functionality

however if i break the level instance inside the level, all the blueprints works on both server and client side

[umbral horizon]

Anyone?

[livid arrow]

currently this only happens client side despite my best efforts. Is there a glaring issue that i have missed as to why the lean only shows for the client?

[karmic briar]

saw the roadmap about Iris and looking at the code,its going to be the replacement for current replication system right?

like how NP was supposed to be?

if what i read so far,will the replication inside CMC and GAS be unify in this case?

[umbral horizon]

The anyone returns?

[twin juniper]

Hi!

I have a problem with movement jitter on the client (left screen in the video), which cannot be seen on the server (right screen on the video). My character setting are more or less standard. I’ve tried almost every trick suggested on the internet but I just can’t seem to get it to work. Any suggestions?

https://www.youtube.com/watch?v=aW8b3xacUtM

Character movement:

[worn wagon]

Can you show your movement code?

The CMC has prediction built in so it should look smooth on the client if you're applying it correctly

[winged badger]

and do not set your skeletal mesh component as replicated

[twin juniper]

movement code is pretty much standard

and component is not replicated

(mesh component)

[worn wagon]

https://tenor.com/view/community-ken-jeong-ben-chang-cant-see-small-gif-5154350

@twin juniper Might be what Zlo said about your skeletal mesh replicating

oh right

I'm not really sure then

[twin juniper]

@worn wagon i'm still confused about the add input nodes

does anyone know a definitive answer to this:

https://www.reddit.com/r/unrealengine/comments/o9rh4w/do_add_movement_input_node_need_to_be_in_client/

[worn wagon]

I'm not sure if it "needs to", but you should yes

And it may need to, I just haven't tested otherwise

The question is what input are you detecting to apply the movement on the server

input bindings are only on the client

So yes, this would only work for the listen server host as it's the only local player running with authority

InputAxis won't be triggered on the server for remote clients

I'm not really sure what is happening in your video, it looks like the movement is being applied on the server and replicated down with a low tick rate. On LAN it should still look smooth even if it was only being applied on the server.

I can't see your whole project though, so it could be a number of things.

[twin juniper]

@worn wagon how would i go on and troubleshoot this? any suggestions?

[worn wagon]

Maybe start with a fresh character with default values and basic movement and try and use that, see if the client has the same issue

Narrow down if it's a problem with your character movement setup or something else

Your movement code looks fine, so you can reuse that.

There might be something you ticked somewhere in your character blueprint that shouldn't have been

Make sure this is ticked too

And your character movement component is set to not replicate

That's how mine is setup anyway, I'm not sure if setting it to replicate would mess it up, but it's not needed.

[fossil pelican]

when testing multiplayer in the editor and using "launch separate server" is there any way to set the server console window position the same way you can set the new window position?

it keeps starting on top and i have to drag it out of the way

[celest bough]

MP is so confusing. Can anyone help me understand why when a client calls a function and passes in their own PC like in the picture, why does the resulting call on the server always swap to the host (or server) PC?

(i know the function says player state, but i tried it with both pc and state and the same thing happens)

[fossil pelican]

im trying to get my head round this kinda stuff myself......I mean i know how it works but feels like you gotta think with portals

since thats an event, the server is calling it though isnt it?

since its a server function

[celest bough]

the server executes it, but im calling it from a client

[fossil pelican]

so youve got a call to "update session score" in your player character or whatever?

[celest bough]

i call it from the users local player controller

and the reason i call it is so the server can store your new score in the game state

[fossil pelican]

when you call that event on your local player controller its telling the server to call it on the server side "copy" of that player controller.

"why does the resulting call on the server always swap to the host (or server) PC?" so you call it on your local client (connected to server) but another controller on the server (the host(listen server?)) is executing it?

[twin juniper]

@worn wagon @winged badger belive it or not, it was camera lag that was causing it

[celest bough]

so basically like i want to use that player controller to display a message to all people of the score the player just got

[fossil pelican]

so you have client (player 2) connected to server (listen server and player 1) and call the event on the local controller (in player 2 client window) but player 1 (host/server) is executing?

[celest bough]

but in the message the the pc always just gives the hosts username

[worn wagon]

Ahhh, that makes sense. Well i'm glad you figured it out.

[fossil pelican]

ok well you need to use a NetMulticast called on the server for that

[worn wagon]

Wouldn't it make more sense to use the playerstate for that?

[fossil pelican]

NetMulticast executes the function on all connected clients

[celest bough]

im trying to use the player state

my plan was to save each players score in a map using that function

[worn wagon]

You said you were trying to store it in the game state

[celest bough]

but then also use the incoming pc to get the players name to tell everyone else

[worn wagon]

You don't need a map, you just need a property that gets replicated in the playerstate

[fossil pelican]

you need a function on your local player than performs a server action.......that server action should update the score in the player state and score should be replicated

[celest bough]

i had it set up so the map stored all player scores

i tried it qwith playerstate and with pc

[fossil pelican]

and a multicast to send a message of the event to all connected clients

[celest bough]

thnis is the full function

but at the end, where im getting the players net id and then nickname

its using the hosts name, despite taking the pc or playerstate from the original function call which is being called by the client

and this is the second function that tells all players of the new score

[fossil pelican]

where are you passing the player state from?

[celest bough]

from the client

the client passes in its own player state when it calls the server event

but it still uses the name of the host when it uses that playerstate to get the netid and nickname

and that is confusing me

and the same happened when i passed in a player controller instead of playerstate

[fossil pelican]

so youre calling "Update Session Score" on your local player and taking the local player state and plugging it into it?

[celest bough]

yes

[fossil pelican]

dont do that, get the player state ON the server

[celest bough]

thats how im calling it from the client

how do i get the correct playerstate on the controller though when i cant imput a pc either

[fossil pelican]

but there, youre essentially passing the local player state over the network to the server. i dont even know if you can do that

you want to get the server side player state

i guess you cant and the engine is using the local player state (which is now the server) as the input

server host

[celest bough]

i guess my next question is, how do i know from a servers perspective which player is making calls if i cant pass in a pl ayer state or playercontroller

[fossil pelican]

you dont need to pass any variables into UpdateSessionScore. You should really be calling Server events on the local controller like "pick up gem" and in there doing playerState->SetGemScore ++ and have gemScore in the player state replicated

[celest bough]

ok so my game basically is set up to be 100% singleplayer but in a MP environment

[fossil pelican]

if you call a server function on the client, it tells the server to call that function on the servers VERSION of that client

[celest bough]

so the only actual gameplay event that happens on the server is to request the pawn

and from that point it plays as 100% singleplayer

with the exception of being able to see other players

and then there is this score posting issue

which is only visual to show everyone the score you got

[winged badger]

again - PlayerStates to the rescue

they are originally made to display kill counts in MP deathmatch

[fossil pelican]

hes using player states, but hes trying to pass the local player state to the server event and update it there

[celest bough]

yeah i guess my question is how do i use them, if its not letting me simply pass my local state into a server called function

[winged badger]

why? PS is perfectly capable of sending a RPC of its own

[fossil pelican]

@twin kite im assuming you have a variable in the player state called Gems, or GemCount or whatever

[celest bough]

nah not in the player state

[winged badger]

just send a server update from the PlayerState and you're gold

and PS is replicated, therefore net addressable, server can resolve that pointer without any problems

[fossil pelican]

so why are you even trying to pass the player state and Gems Collected?

[celest bough]

to get the name of the player

[winged badger]

its super redundant

which class is that in?

[celest bough]

i do everything in player controller basically

[winged badger]

on both client and server instance of player's PC

players PlayerState is GetPlayerState

there is literally no need to bounce the pointer around the network

[fossil pelican]

Zlo, what im wondering is, should that even work? hes essentially trying to send his player state object over the network to the server

[winged badger]

as every single class capable of sending a Server RPC can effortlessly find the associated PS on any machine

no

hes trying to send a NetGUID of his PS over network

[celest bough]

so if i call a server event from a playerstate, and the server event is also in the player state, using get player state will return the client that called the event?

[fossil pelican]

what does the server do in that case? what gets sent?

[winged badger]

not an object

server can resolve the NetGUID into its own instance of that object

[fossil pelican]

ahh

then why is the variable and input blue, for object reference?

in his last screenshot

[winged badger]

i would send a pointer from c++ as well

[fossil pelican]

he says thats his server function called by his local player

[winged badger]

net driver would find the NetGUID for that object

and send that in a package to server

there is plenty going on under the hood that blueprints are oblivious to

[fossil pelican]

so the engine automatically resolves objects like that when you pass them over the network?

[winged badger]

infact, even for development, BP only has about 10% c++ functionality

[fossil pelican]

so you pass in an object pointer into a server function, engine is like....ok this is a pointer, lets resolve this over the network in a much more efficient manner?

[celest bough]

is this correct?

[fossil pelican]

just calling the server event locally is calling the event on the server for that client

[celest bough]

il whip something up real quick and post a pic to see if its still going over my head xD

[fossil pelican]

a server function says call on the client (tell the server the client wants to do this), execute on the server. but it keep an intact channel between the local client and the corresponding client on the server. Local client wont do anything, server version will call the function

look at it like you pulled your local client out of your pc memory, traveled to the server and put that client into the server memory and then called the function

[celest bough]

so this is now on my playerstate

if i do get playerstate from my local playercontroller and call this function

will it work how i want

ignore the missing connection xD

[fossil pelican]

looks like the last call in the chain is trying to replicate to the server, event though this call is already on the server

and since its called in a server event, it will only ever execute on the server

[celest bough]

i just assumed that anything that needed to run on the server needed to be marked as server

[fossil pelican]

nope, only anything you want to call from a local client but execute on the server needs to be marked as server

if its marked as server and called directly on the server, it will still only run on the server

[celest bough]

ah

also this is how my pc is now set up

so this is the local call

[fossil pelican]

yeah this looks more like it

[celest bough]

thanks ❤️ il give it some testing to see how it goes

[fossil pelican]

why is there no target output in your AddScoreToGamestate

[celest bough]

im not sure i understand

[fossil pelican]

well youre passing a player state

[celest bough]

i was

but now due to the conversation, im under the impression that by simply calling the a function in the playerstate, using a reference to self will return the correct gamestate

is this wrong?

[fossil pelican]

no youre right*. just confused about player state being passed and then not being in the event itself

[celest bough]

oh its not being passed in

its because the event is IN the gamestate

so that is the reference input

*playerstate

[fossil pelican]

ahh yes of course xd

[celest bough]

😄

sadge

still not working

still giving the hosts name

[winged badger]

you're still reinventing hot water

you put the score in a PlayerState

you make a widget that takes a PlayerState context and displays name + score

you make another widget that accessed PlayerArray in the GameState, and then adds a PlayerStateScoreWidget in its vertical panel for each PlayerState there

[fossil pelican]

well technically, you reinvent hot water every time you boil it 😉

[winged badger]

PlayerState has Server RPC that just sets score on its server instance and broadcasts the change via event dispatcher

there is no need to complicate, the simpler the code is the less likely it is to break

[celest bough]

so something like this called from my local player controller and executed on the playerstate?

this will update the score on the server?

or this to be more precice

although that still doesnt explain how to get the correct players name since doing this always seems to give the hosts name

its weird because when i test it locally it seems to give different names

but once i get it runnign with steam it only shows the hosts name

[winged badger]

its usually best to catch the class name in any screenshot for this channel

as most of screenshot mean little without knowing the scope

[celest bough]

ah right sorry

its in the player state

[winged badger]

i mean you have the class name top left on the node editor

so you move your logic so you can catch both the logic and that name together in a screen

generally, yes

[celest bough]

im blind, where is it sorry

so from this point after setting the score in the player state, how would i then tell everyone that this specific player has posted a new score

if i cant access their username from this bp

[winged badger]

ofc you can

its GetPlayerName

and it works everywhere

[celest bough]

oh

[winged badger]

you do OnRep_Score

[celest bough]

so thats different from the get unique net id?

[winged badger]

and you fire notifications from UI there

engine should set the anem from netID automatically

*name

and name replicates

[celest bough]

hmm

[winged badger]

so everyone knows it

[celest bough]

in my testing, the top stuff just returned the host name

il try the get player name though

[winged badger]

then you were working with wrong instance of PS

[celest bough]

it was a server function, called froma local PC

[winged badger]

probably not recovered from watching unreal tutorials and used GetPlayerController[Index} at the wrong spot

(you should use GetPlayerController/Character[Index] only if you are iterating over all PlayerControllers/Characters from server or you're doing splitscreen and in no other scenario)

it can even mangle indices during seamless travel to the point where host's controller won't be on index 0 on the host

[celest bough]

I dont understand why this didnt work then

its ran on the server so the get player controller shouldnt matter afaik

[winged badger]

and that is PS?

[celest bough]

yeah

[winged badger]

how do you print the name?

when displaying it?

because if you connected the right hand side of the screnshot

that would definitely break it

[celest bough]

this is in the PC

the event thats called after setting the score in PS

[winged badger]

as executing on server GetPlayerController[0] is almost always the host controller in case of listen server, and first player that logged in in case of dedicated

[celest bough]

yeah

[winged badger]

so

[celest bough]

but i assume that doesnt matter since the event being called from the pc reference is a server event

[winged badger]

your RPC arrives on Server

so now you're in Server scope

then you GetPlayerController[0]

which is server PC

and send it through another Server RPC, which is at this point just a normal function

and when it arrives to the logic you just posted, its always the server's PC

no matter who sent the first RPC

[celest bough]

yeah

but that doesnt explaIN why the string being passed in is always the hosts name

the string being passed in is getting the name from the playerstate that is adding the score, which i assume is the player that posted the new score

and yet once i get on steam, it always just returns the hosts name

[winged badger]

ofc it does

[celest bough]

why though

[winged badger]

because right hand side of this executes on server

and only on server if connected

since the entry point is the server RPC

GetPlayerController[0] will always evaluate to host's controller

[celest bough]

yes but even if i had the local players controller, it would still go to the server no?

[winged badger]

on client instance of the PC, GetPlayerController[0] is the client's controller

on server instance of the client's PC GetPlayerController[0] is the host's controller

[fathom aspen]

Also worth mentioning that this is a MUST in this regard: #multiplayer message

[winged badger]

those 2 are not the same object

[celest bough]

so what is the fix in this instance

[winged badger]

don't use GetPlayerController[0] connected to logic that has RPC as entry point

[celest bough]

i assumed it didnt matter that you called the servers PC because the input is still coming from the player PS

and thus would get the correct name as the input

[winged badger]

it would not

you could send GetOwner cast to your PC class

instead of GetPlayerController[0]

that would work from PS, as PC is its direct Owner

[celest bough]

something along these lines?

this iis in the PS

or would i need to pass the owner through as an input to the function in the PS

[winged badger]

yes

like that

GetOwner from PS returns its own Controller

on server and on owning client

on simulated proxies it will return null

[celest bough]

😦

still not my name in the second score

always the host name

second name should be mine, its using the username passed into that new liveplay score event

[winged badger]

what calls Server Add Score

[celest bough]

the local player controller

[winged badger]

show me

[celest bough]

so this is my game mode when a player joins the game

i pass their PC reference to them and save it as a reference

and thats the reference i use whenever i need a pc ref

instead of "get player controller 0 "

and as you can see in the image above

the name from that PC is correct

the name should be "hairy cabbage" for the scores

it worked for the player join message (using the code above in the GM)

[limber gyro]

this just saved a lot of hours of headache

i was about to ask something when i saw ur conversation

thanks zlo

i wish i had a billion dollars i would hire you on the spot

[celest bough]

and this is the add new score

called from the player controller

[winged badger]

you're doing a lot of things

way more complicated then they should be

[celest bough]

oh i believe it xD

[winged badger]

holding an array of player controllers, why?

[celest bough]

well i use it to tell all players when something happens

[winged badger]

GetGameMode->GetNumPlayers->For(0 to NumPlayers - 1)->GetPlayerController[Index]

one good use for that GetPlayerController function

[celest bough]

i was using it here

[winged badger]

yes, if you use engine instead of custom caching, things break less

[limber gyro]

by the way, i only had the "get player controler 0" issues start to pop up after i changed to the steam net driver, do u think its related or i might have done something wrong along the way that i forgot? i remember having no issues before that change

does the steam net driver changes some stuff internaly that doesnt let the regular "get player controller" work properly?

[winged badger]

seamless travel can shuffle indices

sometimes

ontop of all newb mistales you can do with it

[limber gyro]

what was happening was that only 1 player was getting affected by the UI

[fathom aspen]

That was my thought last night. Would have suggested it to you but you said it worked when using IPs

[winged badger]

i remember Authear crashing the game by using GetPlayerController[0] during HandleSeamlessTravelPlayer

[limber gyro]

so i would spawn 2 players and then the choice i would make in the UI would afect the first player twice

[fathom aspen]

It should almost work the same in both cases

[limber gyro]

thats my impression too but u never know

[fathom aspen]

Doesn't have to do with steam whatsoever

[celest bough]

is is possible my issue is steam related also?

[limber gyro]

well it seems to be working now with "get owner"

[celest bough]

i notice it appears to work properly when i test localy

but when i switch to steam is when i get the name issues

[limber gyro]

and get owner actualy makes a lot more sense from a network perspective

[fathom aspen]

Yeah that's what he told me: "Sometimes in Listenserver the client actually connects fast enough that it ends up as Index0 on the Listenserver. So you end up with the wrong controller if you call that expecting the listenserver's controller."

[winged badger]

always use relative references connected to RPC logic

[limber gyro]

i will be sure to remember that

[worn wagon]

Does this apply to GetWorld->GetFirstPlayerController() too?

[fathom aspen]

That's the same version of that GameplayStatics one iirc

[winged badger]

we do have a rule: someone causes a bug/crash using GetPlayerController[0] and he/she gets to check the entire project for any uses we didn't detect and remove them

[fathom aspen]

You always have relative references at your own disposal like Zlo said

Use them

[winged badger]

GetFirstLocalPlayerController(0 is safe

and should really be added to GameplayStatics, followed by some shock therapy to epic's community managers in order to start using it

[fathom aspen]

Yeah sad but true

[worn wagon]

Someone should really compile all of the stuff that gets discussed in here, there's so much that isn't in the official docs.

[limber gyro]

you would need some one full time just for that

[fathom aspen]

Would save us some precious time here

[winged badger]

that function is equivalent of fucking hot reload in #cpp

[fathom aspen]

Though hot reload is ditched by now, this one isn't

[winged badger]

not on UE4

fortunately, most newcomers start with UE5

[worn wagon]

I've had issues with live coding too though

I'm just in the habit of restarting the editor

[fathom aspen]

It's by no means perfect. Yeah that's a good habit

[celest bough]

ok

so

[winged badger]

i am aware of its limitations, and that it sometimes just breaks because reasons

so can use it safely

[celest bough]

i changed the function to the get player name instead of the nickname from the netid

and it works nowe

so i guess those two things dont give the same thing

on steam at least

[winged badger]

ah

[fathom aspen]

Most probably they don't. UniqueId is invalid for example on NullSubsystem

[winged badger]

that would be because that gets pulled from steam client

i did tell you to use GetPlayerName like 5 hours ago 😛

[celest bough]

player name gets pulled from steam client?

[winged badger]

yes

[celest bough]

ah

[winged badger]

engine stores it in PlayerNamePrivate

which GetPlayerName returns

once

im not entirely sure how it evaluates when called repeatedly, because i've never tried

[celest bough]

ty for putting up with me for a while xD ❤️ glad this is sorted for now at leqast 😛

[winged badger]

now you should rewrite it using 25% of nodes used atm 😄

[fathom aspen]

More correctly, he should move it to cpp 😛

[winged badger]

baby steps

[celest bough]

rofl

[worn wagon]

And of you fuckers know about physics assets/simulations? There doesn't seem to be a channel for it and ue5 general is never helpful

Tired of my shit clipping through the floor 😩

What's weird is it doesn't even go fully through thick floors, it gets stucks inside of it

And I'm not talking about a ragdoll, it's just a single box primitive for a weapon physics asset

[fathom aspen]

Have you tried #legacy-physics ?

[worn wagon]

Oh my bad 😂

[fathom aspen]

I think it's the only physics oriented channel here

[worn wagon]

I just like you guys honestly

[limber gyro]

this cast is failling on the player that creates the session

i create the session and join it and it fails

its connected to begin play by the way

any ideas why that would be the case?

thats a character BP

works fine on the other player that joins the session

[fathom aspen]

Always better if you take full screenshots so we know what the context is

What class is this?

[limber gyro]

its a character

[fathom aspen]

Ok fair enough

BeginPlay fires on both server and client

[limber gyro]

im assuming that it has something to do with the session host being both the server and a player

[fathom aspen]

You are spawning the HUD on both which is wrong

You spawn it only if locally controlled

Add an IsLocallyControlled check there

[limber gyro]

let me check now

still no UI

[fathom aspen]

Are you sure your character is possessed?

Otherwise it has no owner

[limber gyro]

i am, the character walks around just fine and shots

and does all its suposed to do

after that local control check its not firing that "failed" print

but its still not working

isnt the session creator not localy controled?

[fathom aspen]

I don't have sessions experience but I read the comment and it said you are spawning HUD

That's done at local controller

Anyways figure out why it's failling

Ok so for the one that it fails for, watch what GetOwner returns

Debug

Does it return None?

[limber gyro]

i printed the display name its empty

ye its invalid

so its returning invalid in the session creator

[fathom aspen]

Well for client it can be invalid

Owner is a replicated property

On server it has to be valid

On client it's failing

Though why you are using GetOwner if you can do GetController

[limber gyro]

well it was what zlo sugested

when he was helping some one else

[fathom aspen]

For his case it was PlayerState. Both PlayerState and Pawn are owned by PlayerController

[limber gyro]

whats the diference betwen get controller and get player controler

[fathom aspen]

But from PlayerState the way to get contoller is to GetOwner

That's the right way there

[limber gyro]

GetController doesnt work either

[fathom aspen]

In Pawn you have GetContoller

Where is it returning none?

Server?Client?

[limber gyro]

well thats a good question

[fathom aspen]

For server you can use Possessed event if you want to be sure it's there

[limber gyro]

im assuming its i nthe server

since its the sessions creator calling it

[fathom aspen]

[limber gyro]

i am already possesing the character

i spawn the character then posses it in c++

[fathom aspen]

Nice

Use Possessed event

Instead of BeginPlay

[limber gyro]

it works on the possesed event

interesting

so maybe the begin play is just too fast and the PC is not there yet?

imma try a delay to see what happens

[fathom aspen]

BeginPlay can fire without the pawn being possessed

[fathom aspen]

Will work

Though they are not a good practice

[limber gyro]

ye

[fathom aspen]

Always use such events

[limber gyro]

works with the delay

[fathom aspen]

When possible

[limber gyro]

on possesed is actualy giving me the same issue on the clients now, im gonna stick with the delay i guess

[fathom aspen]

Well possessed is only called on server

So it won't be valid on client

There should be an event to when your controller has replicated. Something like OnRep_Controller

[limber gyro]

that would make the bp more complicated i think

[worn wagon]

Yeah these issues are annoying

I've had to use a combination of BeginPlay, Restart, and OnPossessed to gets things to work properly in multiplayer for pawns

[worn wagon]

It would but it's necessary

[faint eagle]

afaik properties replication has some smart mechanism to not replicate and actor that is very far away from a player. Do the same rules apply for RPCs? If I send multicast RPC from server on some actor is it called on all players, or only to players within some relevant radius?

[fathom aspen]

You can't expect things to work on BeginPlay like you want. OnReps are inevitable.

[limber gyro]

I dont wanna say anytthing wrong but i think there os somethng like that, teu searching for "NET relevância"

[fathom aspen]

Only relevant players to the actor the multicast was fired on

[limber gyro]

Jesus this auto correct is killing me

"net relevancy"

The docs mention some stuff about range, but i cant remember

[fathom aspen]

NetCullDistanceSqured. It's the distance squared

The distance is 150 meters by default

[faint eagle]

cool, thanks

Another question. Why is OnRep called only once when I'm replicating property with the same value even though I've set the replication condition to REPNOTIFY_ALWAYS? I'm using push model for this property. I can tell for sure that the OnRep fires once, but only once, even though marking property dirty fires multiple times

[chrome bay]

It's only ever sent when the server thinks the client has a different value

REPNOTIFY_ALWAYS just means that the client will call the RepNotify function even if it receives the same value it has locally from the Server

[faint eagle]

hmm and how does the server decides whether the client has a different version or not?

[chrome bay]

It keeps a history

And a shadow state of each clients' value of each replicated property for every object

You can't force the server to send a property to a client, it'll only ever send when the last acknowledged value doesn't match

[faint eagle]

how can it be sure that the process on client doesn't change the property? by user input for example

[chrome bay]

It can't

That's why you shouldn't modify replicated properties client-side unless you're doing something special, like prediction

Otherwise you can end up permanently out of sync

PushModel realistically does next to nothing

[faint eagle]

hmmmmm ok thanks 🤔

i was thinking about replicated properties and push model as somewhat "lazy" reliable RPCs like I wanna make sure that replication reaches clients but I'm not really concerned how fast does it happen

[winged badger]

push model i estimate is 5% gains if you're lucky

[fathom aspen]

Net Manager > Push Model

[chrome bay]

I mean it sort of already does that really, push model really just means "don't compare this property until I mark it dirty"

[graceful flame]

Could you please briefly explain the difference between the two?

I'm just using onRep and RPCs as needed. Also doing some client side prediction here and there but I'm not entirely sure what those two terms are.

[thin stratus]

So

Who wants to tell me about Iris

I'm pretty sure someone here already looked at that stuff :D

https://portal.productboard.com/epicgames/1-unreal-engine-public-roadmap/c/868-iris-replication-experimental

For those who have no idea why I ask

[graceful flame]

oh yeah I saw that on the board

perhaps ue5-main has an experimental plugin? I'll have a look

[quasi tide]

#cpp message

[graceful flame]

ohhh what's this??

[thin stratus]

https://github.com/EpicGames/UnrealEngine/commit/4aae8d3ed0bc8c1a6c293c780413e2c5f35150e8#diff-2731bf5b124802178b02a5900665f41a70616fae57b78549b3adec0c9c47e8dd

[quasi tide]

What I linked is all that I've seen anyone talk about regarding Iris Cedric.

So it's super unknown at the moment.

[thin stratus]

Thanks!

Sounds like a replacement for the current system?

Strange though

[quasi tide]

Possibly?

[thin stratus]

Weren't they just in the process to go push model?

[quasi tide]

Or maybe it'll be like push model where it is opt-in

[thin stratus]

I mean I'm all for it

If it allows more players

Then it must be very "new"

As in, remove existing stuff

Might be using push model through and through

Hopefully integrates with the prediction plugin..

[quasi tide]

I'd like even like...a small piece of documentation about it.

That person I linked thinks it's to help network Chaos

[thin stratus]

The commit does seem to touch GAS and NetPrediction

they should really make sure everything works hand in hand

Networking is hard enough already

[quasi tide]

Could also be for Mass as well.

¯_(ツ)_/¯

I don't know enough about networking low-level to actually dig through and theorize 😅

[thin stratus]

Me neither tbh

I just want things to be in a working state

Preferably with less problems :D

[quasi tide]

Let's hope Jambax gets bored one weekend 🤣

[thin stratus]

"I'm gonna rewrite this shit and make it predictable from CMC over GAS to Mass and Chaos!"

The dream

[fathom aspen]

Push Model was explained the sentence above. It's main objective is to reduce server cpu time by not comparing properties on intervals if they changed, but telling the server hey: this value changed, replicate it. Net Managers aim for the same goal, i.e. reduce server cpu time, though they yield more noticeable results. What they do is that you turn off replication for actors and let some other net manager actors handle the replication of their properties. A great exclusive article that was written on this by vori: https://vorixo.github.io/devtricks/network-managers/

Note though, that the article only goes over actors that are placed in the level. Actors that are spawned at runtime are a bit more tricky to handle though it's doable

[fathom aspen]

That's good, though imagine you have thousands upon thousands of actors. That's where these two shine

They can work in tandem, though the latter is the game changer

[graceful flame]

ahhh okay so my game only has about two dozen replicated actors at any given time. 4vs4 players, and some level actors

So maybe something to read up on but not spend too much time implementing....yet.

[fathom aspen]

Then you don't need to worry much about it ^^

[thin stratus]

Right, but PushModel isn't everywhere in the Engine yet, right? and Blueprints aren't using it at all or?

If Iris aims to reduce server cost and similar, then it ultimately aims to reduce the cost of replication itself. So it's basically on a similar level as the PushModel attempt.
Haven't looked at the code, but Iris may just be using PushModel fwiw.
But then more.

We now have like 3+ systems in the Engine. Normal Replication, PushModel and that ReplicationGraph. having Iris as a 4th+ is annoying

I would rather like seeing them clean stuff up instead of adding new stuff in addition

[quasi tide]

https://imgs.xkcd.com/comics/standards.png

[thin stratus]

:D yeah

[fathom aspen]

There is a function that is exposed to BP iirc. Also you can use it in exclusive BP projects. The only gameframework class that I know that uses them extensively is PlayerState 😄

[fathom aspen]

Yeah I haven't looked at that Iris too, beginning @pallid mesa to explain it to me xD

[pallid mesa]

iris is like a default push based model without scanning

[fathom aspen]

I assume if Iris does something similar to the PushModel then there's a good chance that the PushModel is going to the vault?

[fathom aspen]

So it's PushModel++

[fathom aspen]

Then this could be the case damn

[fathom aspen]

Yeah the engine definitely needs a cleanup. For example I was faced by this OverrideWith nonsense lately which you and James a while back literally ranted about it lol

[lament minnow]

is there a way to snap a spring arm's rotation lag back to 0? when spawning my actor and setting it's position at the beginning of the game the spring arm is doing a weird rotation to get into the correct orientation.

[thin stratus]

Setting the boolean that turns it on and off might work?

[lament minnow]

i'll give that a try, thanks.

ok, so if i set the bool to true after 1 frame of setting the spawned location/orientation it's snapped to the correct orientation, thanks 🙂

[celest bone]

I'm looking at creating a testing level for our game, that is multiplayer. I only ever want one of these sessions open, so I want a button that either creates the session if it doesn't exist, or joins it if it already has been started. Any way to do that with sessions?

[pallid mesa]

there is more to it, but something like that is definitely possible

basically on your common entry to create a session or not should do first session discovery, if all the sessions found are full, create a session, if not just join a session

[celest bone]

I will have a mix of traditional sessions, that load a standard world, and this one session that loads a specific map.. any way to differentiate between these when doing session discovery?

[pallid mesa]

you will need a online subsystem for session discovery and creation ie: steam, eos

huh? mind clarifying

two maps

or...

something else?

[celest bone]

So there is the standard world, that the main create/join session system will use.

In addition, we have a testing level, it's a small level purely to test mechanics, that we want a menu option to create/join automatically

[pallid mesa]

well you can open the desired level with the ?Listen parameter

and clients can hard travel to it

from whichever map as long as the previous session is handled

common user plugin might help

take a look at Lyra session management code

[celest bone]

Awesome, that gives me a lot to search for, thanks!

[fallow shadow]

Hello, i am trying to set an actor's location but i do not have much luck. The character is always jittering. I understand thats because the client and the server both try to set the new location but i am only setting this on the server. Does anybody have any insight as to how i could fix the jittering?

[pallid mesa]

To remove all the jitter you have to put the character predictively in the same position that you are placing it in the server

also

if you are in the server you have already authority

so that authority check is irrelevant there

where are you calling this code from?

[fallow shadow]

So call a local event that sets the actor's location and then call the server event?

[fallow shadow]

i am calling this from a function(The function itself was called from the server)

[pallid mesa]

which function

you can only server rpc from a client owned actor

[fallow shadow]

Need a screenshot?

[pallid mesa]

if you are already on the server, doing a server rpc does nothing

yeah sure

put more context to the problem 😄

it always helps!

[fallow shadow]

I just thought of running the event on the server as there might be sometime where i won't be calling it from the server(but i will be calling it from a client owned actor)

[fallow shadow]

Just a moment

[fallow shadow]

The two instances i use the server function

[pallid mesa]

where are those two functions called from?

[pallid mesa]

DoDamage isn't relevant here, right?

but as you can see in the bottom image you sent your LaunchCharacterToAir...blahblah

is already on the server

so all the functions called from there will also be called on the server

where's LaunchCharacterToOnAir... called from?

[fallow shadow]

So i can just not replicate the said events? I mean they are already running on the server lol

[pallid mesa]

they are already on the server x'D

also I'm so sorry for saying this

[pallid mesa]

but... where's this called from

[fallow shadow]

no worries. It's called from an animation notifier which is placed inside of an animation montage

[pallid mesa]

also, where is this function being called

[fallow shadow]

I think you replied two times on the same picture

[pallid mesa]

correct

that was intended

XD

[fallow shadow]

So one time for the interface and one time for the event?

[pallid mesa]

correct, where's that interface being called from, and where is that interface implemented

[fallow shadow]

So you see the implementation of the interface on the screenshot you replied and here is the place i call it from

[pallid mesa]

what's that class a character?

yes nvm it is

depending on your setup

you might be in luck and your anim notify might be called also in the server

so you might not need to replicate anything

sorry on-off cooking

so this is convenient, as you have execution flow parallel in server/client

which allows you to do stuff predictively

basically to ensure your execution context

in blueprints you can add a print

it will say Server: or Client: based on the execution context

if you are already on the server you don't have to server rpc

[fallow shadow]

okay i will add a print on the events and let you know what they say

yeah it does get executed on the server side

[pallid mesa]

where did you add the print?

[pallid mesa]

no

add it here

[fallow shadow]

It says client

[pallid mesa]

only client, not server?

[fallow shadow]

Only client

actually no it had both the client and the server

it actually had every client

1 2 and 3

along with the server

mb 😓

[pallid mesa]

okay if its on the server, then no need to send a server rpc

since you are already on the server

now if you wish to execute code in the locally controlled pawn, which is likely your code

just add a islocally controlled

because you are only interested in the locally controlled pawn to perform the predictive code

parallel to the server execution

[fallow shadow]

Should i add said code on the final event(The set actor function)? or after i have called the set actor function?

[regal geyser]

Is there an event which is called when player fully loaded new level after seamless travel? GameMode knows for how many players it needs to wait to start the game, but Handle New Starting Player is triggered before player's level is fully loaded and I'm not sure how I can wait for all players to be fully loaded in for a game to start.

[fathom aspen]

The source code says otherwise

HandleSeamlessTravelPlayer can be called before the client has finished loading world just in case it was an AIController ^^

Which is not relevant

If you want to make sure all players has fully loaded then check when SeamlessTravelCount is something you want and then you're good

This was talked about not a while ago: #multiplayer message

#multiplayer message

Search tool is ❤️

[regal geyser]

Thanks a lot for you help, I tried looking in SeamlessTravelCount variables but it seems they are not exposed to blueprints if I'm not mistaken

[fathom aspen]

Yeah I don't think any of this are 😦

BP is so limited tbh

You might find some workaround but it just time consuming and ends up looking weird

[regal geyser]

Yea.. I don't really understand why some crucial data still aren't exposed to blueprints.

[winged badger]

sadly, best workaround for blueprint networking is to just use c++

[fathom aspen]

FACTS

[limber gyro]

hey guys, my options are not being carried over properly, im guessing that i am doing something wrong in the BP

the line of code called in "initGameState"

playersPerMatch = UGameplayStatics::GetIntOption(FCommandLine::Get(), TEXT("playersPerMatch"), 2);

[fathom aspen]

?listen goes to the options string

Not level name

[limber gyro]

in my experience its the same

altough it would look cleaner in the options

[fathom aspen]

Well yeah you prolly right, it just constructs the URL based on the two 😄

Though what is combo box string has?

LevelName?

[limber gyro]

ye

my issue is the number of players no being passed

[fathom aspen]

Well

Did you print the string?

What does it output if you print it

[limber gyro]

u mean the options being passed?

[fathom aspen]

Yes

[limber gyro]

looks correct

[fathom aspen]

How do you print it?

[limber gyro]

with a print node

[fathom aspen]

The one in GameMode

?

How do you retrieve it

[fathom aspen]

That's before

How do we know it persists after the travel?

[limber gyro]

u mean on the gamemode

[fathom aspen]

I want to know it persists after the travel

It's cached in the GameMode

Yes

[limber gyro]

let me check. i was under the assumption it would just work since its in the options field

[fathom aspen]

You can print it when you travel to the new level

[fathom aspen]

Well it can be invalid

Always debug

[limber gyro]

imma do a UE_LOG

gimme a sec

ye its wrong

LogTemp: Warning: -skipcompile

thats the only thing being passed

maybe im getting it wrong

FCommandLine::Get()

is this not the correct method?

[fathom aspen]

Well you already got it there in the GameMode

Cached

If this is the first connection you can simply print that one

AGameModeBase.OptionsString

You simply print it in BP

On tick w/e

In the GameMode class

[limber gyro]

ye so thats the variable that i am looking for

i will try that

[fathom aspen]

This is how it should look: LevelName?listen??playersPerMatch=NumOfPlayers

The ?? shouldn't be an issue, though you can stay with one if you remove that ? down there

[fickle igloo]

Is there any way for PIE Net Mode "Play as Client" to NOT start a server in the background? (this should effectively be how it acts as a 'packaged client'). I don't think this is the same as 'Play Standalone' as many things behave different in that mode (IsServer/HasAuthority/Client Side Pathfinding).

[sinful tree]

Standalone is the way to launch PIE without a server. Listen Server means that the first player acts as the server. Standalone is as if you're playing a single player game, not connected to a server.

Standalone effectively acts like the server as well, as it is the "host" of the single player game 😛

You can have the standalone instance connect to an external instance of a server in which case it'll start acting like a client.

[fickle igloo]

Hmm I'll double check that. The issue I was having there is that the 'play as standalone' was having some blueprint functions behave differently then when in 'play as client' . While I sometimes want to connect to a dedicated packaged server for debugging, sometimes I instead want to connect to a auto-made one for quick testing. I was wanting to use the same blueprint code in both cases. I wasn't testing post-connect though, only on level init, so if it changes it's behavior after doing an 'open level' that might work...

[fickle igloo]

Was going off this picture here, where it shows that "has authority" is different on client mode vs standalone

[fathom aspen]

IsServer shouldn't be behaving any different as it checks that your net mode isn't NM_Client

So works same on all types of servers and standalone

Even HasAuthority. Standalone always has authority

[fickle igloo]

even after connecting to a remote deticated server?

[fathom aspen]

No. Then he's a client

[sinful tree]

That image shows that the only one that doesn't have authority is when the netmode is NM_Client.

So if you play standalone, you're going to be authority.

[fickle igloo]

so the key seems to be, that the net mode can be, and is, changed for you at runtime, which I didn't think was possible (I thought it was set once you hit the play button, and unchangeable)

[sinful tree]

Yes

When you connect to a server, your netmode would change to NM_Client, meaning you won't have authority. If you start hosting a game, you're set to NM_ListenServer and have authority.

[fathom aspen]

That's not the case. You can launch as listen server with another client, and make the other client host a new map as listen server and make the listen server join him. @fickle igloo

Net modes flipped

[fickle igloo]

ok, I'll proceed with some attempts under that new understanding then. Thanks you two 👍

[fluid summit]

Hi everybody! where do you think it's better to keep the Equipped items info? Player State, pawn or maybe other place?

[sinful tree]

Probably a component on the character?

[fickle igloo]

do the items go away when the character dies, or does it respawn with the character?

[fluid summit]

They respawn with the character

it's your regular arpg (diablo, path of exile, torchlight, etc) setup

[fickle igloo]

I've heard augments made that it's better to store them in PlayerState in that case, since if you destroy the character you'd have more steps to rebuild the items equipped

[fluid summit]

on my previous setup i had it on the pawn, but i'm having doubts exactly because of that, makes more sense on the PS

[vale grove]

how do i do multi user editing in ue5?

[livid arrow]

there is documentation on how to set it up, but it is a plug in you need to activate

Can anyone see any issues with this? currently this only shows on the owning client.

[fluid summit]

Execute RPC on tick sounds like suicida by performance issues

Also, could it be that it's executing on Server, but the values you get com "last input vector" don't lead to any change and they look like it's not running?

[livid arrow]

the on tick is simply to see if it works, and Im not sure what you mean. can the server not read the last input vector?

[fluid summit]

if you are not replicating the movement you will get different values, do a print on the values and check just in case

also make sure "Cube2" is valid

[livid arrow]

cube2 is valid. when I print the values the server seems to only read the host clients values. however, i still cant see the rotation of the host from a client

[vale grove]

ok so basically

do i need a vpn?

because it just doesnt work with my client

[livid arrow]

you do if you are trying to work with someone outside of your local network. I used hamachi when working with my friend

[vale grove]

vpn?

[vale grove]

vpn?

and yes we are in diffrent states

[livid arrow]

you will need to spoof that you are on the same network

or have access to an actual server running the multi user editing server

[sinful tree]

Last Input Vector from the CMC isn't replicated at all, even the server doesn't know this value, so it can only be used on the local client. So you'd probably have to pass that through the RPCs or use a different value.

[livid arrow]

what would I do to get that value replicated? would i just make it a replicated variable? sorry if I miss stuff, i am still new to multiplayer and networking stuff

[sinful tree]

Create a Vector input on the Server and Multicast events, and pass the value through from the client to the server, then from the server to the multicast.

Also doing the below will cause the server to call the "Lean Server" function twice as event tick runs on both the server and the client. You'll need to put a "HasAuthority" node directly after Event Tick so only the client calls the event.

[livid arrow]

alright thank you, I will try this.

[harsh oyster]

Hey, I was wondering... I'm currently working on multiplayer for a battle royale game, but I'm a bit confused about how the servers work. Is it done by creating and hosting sessions, or is it automated on a dedicated server? How?

[short arrow]

RPC won't really be a problem for the server as long as it's not set to reliable

[fallow shadow]

That doesn't seem to work. I have done it like this but it doesn't seem to be working

[pallid mesa]

what are you doing XD

in the anim graph anim notify node

[elder sable]

Is it possible to use beacons in PIE ?

[pallid mesa]

check if the owner is LocallyControlled or Authority

if it is then you dont need to have rpcs at all

so step #1 remove all rpcs @fallow shadow

[fallow shadow]

Done

[pallid mesa]

step #2

and a branch with a IsLocallyControlled Or HasAuthority

[fallow shadow]

like this?

[pallid mesa]

you can do trygetpawnowner in the anim BP

in which you can check for local controlled pawns

[fallow shadow]

I am not using skeleton notifiers.

I am using anim notifiers which are a separate class

[pallid mesa]

you are using an anim notify?

[fallow shadow]

yeah

[pallid mesa]

anim notifiers can be implemented in the anim graph

unless you are using...

[fallow shadow]

I am using this

[pallid mesa]

ah yeah so the anim notifiers

can be implemented in the anim graph basically checkout the matthew wadstein video about them

but basically they can also be implemented in their own object

[fallow shadow]

Are there any noticable differences in implementing them in their own object or in the anim graph?

[pallid mesa]

functional mostly, let me send you the video because over chat explaining them might be a bit iffy

https://youtu.be/vY8ENkjBY2I

but the principle is the same, you can get the owner of the skeletal mesh which which can be a pawn

and then from there you can check if its locally controlled

[fallow shadow]

okay let me try then

Also if it has authority do i not call anything?

[pallid mesa]

if (has authority OR IsLocallyControlled) then proceed

this basically ensures thay your local controller will get execution flow aswell as the server

so you can predictively set values in the client

[fallow shadow]

like this?

[pallid mesa]

dont make the pawn cast pure

[fallow shadow]

In case it fails?

[pallid mesa]

and then it would be a matter to revise the rest of the logic, but now you got a server/local client execution flow, which is exactly what you need for prediction

[pallid mesa]

nothing

[fallow shadow]

So now, all i need to do is call the local events and right after the same events but on the server side?

[pallid mesa]

no

they are already gonna be called in server and locally

hehe because remember that the anim notify

gives you a server execution flow

think of it as execution flows

or contexts

if you are in a server execution flow u dont need server rpcs

cause u are already in the server

[fallow shadow]

Yeah, i got that yesterday.

But do i not need to do some code to predict the values locally? and then pass them onto the server?

Also when i am hitting the enemy character is jittering on my screen(not his local screen)

[pallid mesa]

so you got execution flow in the client

already

but its local client

so prediction consists on performing actions in the local client before they happen in the server

so you can see a 0 lag simulation in your client

so if the logic is equivalent in server and client you will not get snapped back in this case since its about movement you dont need rollbacks

since the cmc will take care about rollbacking you

[fallow shadow]

Yeah that's the idea but if i am to set the location at the same time do i not need to call the two events back to back?(First for setting the new location locally and one time on the server). What am i missing here?

[pallid mesa]

no, remember that this execution flow is in the local client and the server

if you set, for example, the actor location to 0,0,0

what will happen is that your client will set the location and then the server will set it

with no RPCs

because remember

the execution flow we got is server and local client

so the same white wire

is doing local client execution flow

and server execution flow

because anim notifies give you said benefit

• the logic we added in there

[fallow shadow]

I see

But i can tell you that the set location is still jittering lol

[fallow shadow]

I am thinking that we should call different events based on whether it has authority or if its locally control. Right now i am calling the same event which doesnt make much sense given that one is executed on the server and the other on a local client

[pallid mesa]

what do you mean?

[fallow shadow]

so we have this

[pallid mesa]

correct which gives you the proper execution flow

for predictive actions

[fallow shadow]

So it's like running two parallel functions?

[pallid mesa]

yes one server sided and one in the local client

but

the local client one comes earlier

unless this is server initiated

[fallow shadow]

No, the client does come first

So what's causing the jittering now?

[pallid mesa]

it depends on your logic

basically try to set an actor location to 0,0,0

right after the execution flow we created

if you get a smooth as butter result in your local client then it means our execution flow works predictively

dont call any of your custom logic

[fallow shadow]

like this?

[pallid mesa]

yes we are simply testing

correct

as long as your 0,0,0 is fine

you should feel a smooth teleport

[fallow shadow]

Yeah it is smooth

[pallid mesa]

then we got our prediction working 👍, now you can test it better by enabling network emulation

and setting average lag

in play settings

[fallow shadow]

Quick question. Would this be affected by high latency?

[pallid mesa]

thats what im about to show you

haha

by enabling network emulation in the play settings and setting average lag

you are simulating a laggy scenario

[pallid mesa]

try everyone and average

[fallow shadow]

like this?(for average)

[pallid mesa]

emulation target everyone

yes thats about 100ms if you set it to everyone as I mentioned

thats what we wanna test

so the good thing about predictive actions is that even if we have high lag, we will feel the smooth experience in our clients end

[fallow shadow]

Yeah it is still pretty smooth

[pallid mesa]

thats very great!

you see? thats the advantage of prediction

buuut

predictions can fail

:(

and this is the gotcha that a prediction system has

predictions woooork really really well if your data is baked

or directly available

now... if your data has a runtime factor...

for example u do a capsule trace or whatever to obtain your data

it might happen that the server side capsule trace and the client side capsule trace

dont match

because remember they are executed in different timeframes

in such case you will get different results in client and server

meaning that your prediction will look off

so now your work consists on revising your logic to detect cases in which the server might produce different results than the client

for such cases u often do a trust and verify heuristic in which u totally trust what the client said

to do the predictive action

but you gotta check it afterwards in the server

that is the case when we do predictive shooting

in online shooters

[fallow shadow]

Quick question, why would we care about what happened in the client? I mean do we not know that whatever the server results in is 100% accurate?

[pallid mesa]

yes but when you are playing a shooter

and your latency is reasonable

we want to give the client 0 latency on his shooting

so on the server when we get to validate the shoot

we HAVE to rewind the game

to the point in which the client shooted to ensure the hit was valid

assuming linetrace shooting!!

basically because we want responsiveness!!

imagine a shooter in which ur shooting is capped by latency

players will be mad with you

😄

all of these techniques are implemented in Unreal Tournament

thats why its a very valuable resource

[fallow shadow]

Now i get what u r saying

But doesn't rewinding take some time?

[pallid mesa]

well what games often do

they have a list of actors that should be rewound

like... characters, moving platforms... etc

when you shoot only the relevant ones are rewound

[fallow shadow]

It still sounds like a lot for the server to do in a split second

[pallid mesa]

so basically you store server side a vector of positions in a fixed timestep

per each candidate actor to be rewound

and when you shoot

you simply select the position that was valid for your shoot

so its simply an array lookup on a list of candidate actors

btw im speaking about a competitive shooter

you can avoid these rewinding stuff by doing an approximate location with client leeway check

but on a competitive shooter

like valorant... or such

you should do this

[fallow shadow]

I see, it's an interesting concept. I would really like to see it implemented though. So much data has to be processed in such little time.

[pallid mesa]

not really hahah its okay as long as you scope it

lots of games do it

like... Unreal Tournament, PUBG... yada yada yada

to see an implementation of this

you can checkout Unreal Tournament source code

[fallow shadow]

I just might lol

Also i wanted to ask you something else

Can we do what we did for set actor location, for the launch character node? Do the same principles apply?

[pallid mesa]

if the data is baked yes

[fallow shadow]

is this considered baked data?

(Both screenshots are on server side)

[errant vapor]

is there any way of ensuring that the client(s) receive a net update when doing a low update frequency(alternatively dormancy) on an actor? im using the replication graph and i have thousands of actors that change very rarely and rely on forcenetupdate when they do change.. however, in packet loss scenarios, a client will occasionally miss one of these updates and then has to wait until a new forcenetupdate to have a chance of synchronizing.. id ideally want the server to keep pushing that actor's update every few frames until its received an ack from each client, then going back into dormant/lowfrequency

[pallid mesa]

wym server side? isn't this called in local client and server?

[pallid mesa]

forcenetupdate or flushnetdormancy

[fallow shadow]

The screenshots i sent are part of the take damage function which get executed on the server side alone

[pallid mesa]

if take damage is server only... theeeen there is no room for prediction in the afterexecution flow

you can however bring down the event to the client from the server, formally called a server initiated action

[fallow shadow]

What if i call a client only event and in the client only event i execute the launch code along with a server version of the launch code?

[errant vapor]

youll note im already using that.. my problem is when a client misses one of these forced updates from the server, in which case it could take minutes/hours before another forcenetupdate happens, and the clients version of the actor is stuck in the wrong state until then. im looking for a way of guaranteeing that that particular update reaches the client(s)

[pallid mesa]

yeah sorry i didnt fully read you

are these actors dormant initial?

part of the level?

[fallow shadow]

They are part of the level yes

they are character BPs

Actually they are the player character

[pallid mesa]

no not to you FanMan I'm with Trog now

haha

hang on a sec

[fallow shadow]

Oh okay, we have the same icon as trog and i got confused lol