multiplayer

[thin stratus]

Actually

Taht was the wrong part of the code that I posted for the radom

// if it is relevant then mark the channel as relevant for a short amount of time
if ( bIsRelevant )
{
    Channel->RelevantTime = ElapsedTime + 0.5 * UpdateDelayRandomStream.FRand();
}

It's this

That's where the + 0.5R comes from in one of their comments

[lament owl]

Thank you very much !
I've googled about 2hours, I can't find anything about that.
I'll read you're answer slowly again.

🥹

[thin stratus]

So they basically have the following delays in place:

• Only check Relevancy when "RelevantTime" has passed for 1 to 1.5 seconds.
• If Relevancy changes, only actually make it take effect if the RelevantTimeout has passed.

And again, don't change this in a global fashion.

Changing the RelevantTimeout (config variable) to e.g. 0.0, will cause all your Actors to spawn in and out

If you want control over this, move/create those variables on the Actor level and give them the same defautls

e.g. 5 seconds for the timeout and 1.0 seconds for the delay between IsRelevant checks

It's a very simple change. But that's somewhat the limit of it. You will still have a small delay on clients due to ping

[thin stratus]

No worries. I'm always happy when someone benefits from me having lost my mind again due to some random sh*t.

[lament owl]

So spawning's delay is intended, right?

[thin stratus]

Spawning and Despawning is somewhat intended by default.

You can lower the Timeout via config, without changing the engine

But you keep the 1 to 1.5 delay in relevancy checks

And you can't set the Timeout to 0

So without Engine changes you probaly get down to roughly 1.1 to 1.6 seconds delay, if someone would go in and out of relevancy instantly by crossing the threshold or you returning true/false on a given actors IsNetRelevantFor function

Spawning in should be "Instant" (+ ping) if it has been longer than the timeout

Well actually, instant unless you actually hit the relevancy check delay

If it was just checked and was false, and then you change it, it takes 1 to 1.5 seconds before it gets re-evaluated

99% of a time, this is enough, as RelevancyRange is quite large, so the player won't notice

I only had to touch this due to that game being a MOBA

Where you have a small map and you can see people walk in and out of brushes

And we can't really have them just be hidden.

Cheaters etc. :P

[lament owl]

I'm doing similarly, I'm making FogOfWar uisng Replication Graph, so finding visibility about NetCullDistance.

[thin stratus]

Makes sense. We didn't use RepGraph there. But I assume it still uses the same NetRelevancy Code in the NetDriver

Until you tap into Iris I guess haha

[lament owl]

how about iris? it's performance can really replace RepGraph?

[thin stratus]

Can't comment on that. Have never replaced a really big RepGraph setup with Iris

[nova wasp]

Just about anything is faster than the old unreal netcode backing... I don't know for sure but I would be willing to bet it's far faster

Iris is relatively hardcore c++ in that internally it operates on mostly dumb arrays and doesn't bounce around actor channels and poll things

as for if it makes relevancy popping better... no idea

in some ways Iris has to bend over backwards to mimic how the old netcode worked to maintain feature parity (subobject replication order for example)

you can just try turning it on to see but you would need to replace things like custom serializers and any repgraph would beed to be replaced

also be warned some funny things may happen where onreps happen in orders you don't expect

[lament owl]

Interesting.

I've seen really many code about iris in engine like NetDriver, so curious

like macro #if IRIS /../ #endif

[nova wasp]

yeah, it's kind of sice-car'd on to the netcode

they can kind of work at the same time hilariosly in some cases

[twin juniper]

I'm currently using independent actors for the bullets in my gun, and I've set their replication to Replicates = true. Is this approach optimal for performance in a networked environment, or could it lead to potential issues with networking efficiency?

[lament owl]

bullet has any speed and simulatePhysics?

not using linetrace?

[twin juniper]

I'm using PMC

Projectile Movement Component

[lament owl]

I think you're right, in some lecture like udemy, I learned samely. using PMC

projectile rifle like PUBG

[twin juniper]

these days, good looking bullets are not only a line trace lol most of the time

[lament owl]

You can see how ShooterGame did it in github, ShooterGame->Weapons->ShooterProjectile.h

[thin stratus]

Idk if Lyra has projectile weapons, but that would also be an option to look at, given ShooterGame is a bit outdated.

The whole ActorReplication for Projectils thing depends largely on how many you want to spawn. And you#d probably still want to do some prediction for slower moving projectiles.

[twin juniper]

@hoary lark Even ShooterGame from UE4 is using

bReplicates = true;
SetReplicatingMovement(true);

[twin juniper]

about few hundreds during a full battle moment

[thin stratus]

Keep in mind projects like Lyra and ShooterGame, while being meant as an example, never had to deal with actually ensuring that whole thing runs well for lots of players.

They are examples after all. It can totally be that Lyra and ShooterGame fall apart when actually put into play, and require CPU and Bandwidth optimization

[twin juniper]

Is there a better way then for doing this? (optimization)

[thin stratus]

Honestly, really depends on your game. You can start with that fwiw and then iterate on it

[twin juniper]

I'm not seeing how I would optimize from there tho

[thin stratus]

No one here will be able to replace you implementing a solution and profiling it on a large scale test I'm afraid.

You could have a single Manager Actor only replicate the Transforms of Actors that otherwise are spawned individually locally.

There are lots of ways.

[twin juniper]

Because currently, it's basically replicating when it feels like it should automatically?

[hoary lark]

Normal actor replication of bullets isn't even a starter option for many games imo (since then you have no sensible client side prediction). "It depends on your game" is the only real answer

My prototype was for a 4 player coop, no pvp, so client auth, easy mode

[thin stratus]

"automatically"?

[twin juniper]

well what I'm currently doing is spawning it on the client at first for prediction, which works well

[twin juniper]

if a properties changes, it will replicate it automatically...

[thin stratus]

If your Actor and the property are marked as Replicated, sure

Otherwise, no.

[twin juniper]

mhm, then spawning it on the server replicates it automatically

[thin stratus]

Correct

Which, if you spawn locally to predict, will create 2 instances

You can check the UnrealTournament code how they handled that for slow moving projectiles

[twin juniper]

I also do it for fast projectile

I was more wonderying about collisions, if the Client Prediction bullet hits something, what should happen? (Going to server but what would it check), if the Server Bullet hits something, then what do we do?

[thin stratus]

The Client Bullet is predicted and despite visual you might really not want to predict anything else.

Spawn some VFX, and SFX and leave it at that. Damage can be handled Authority-side only.

[cobalt notch]

The New Window doesn't use the editor viewport. You can do selected viewport and your main editor window is 1st player and the 2nd player is the client window. This is like what you want.

[thin stratus]

Does anyone know how Satisfactory's Server Manager works? Is that just a Beacon Setup?

[oblique condor]

So i packaged a windows debuggame dedicated server, and a new error in a similar function path popped up:
It crashes on Actor->GetName()
Most likely because the logs were disabled in the shipping build
How exactly can I track down what actor is pendingkillpending
The debugger info just shows nothing useful:

[oblique condor]

So I found the actor, it is "WorldDataLayers"

AND it seems there's a forum post about it: https://forums.unrealengine.com/t/crash-when-seamlessly-travelling-from-world-partition-map-ue-214626/1914873

[neon mango]

What's your issue?

[ruby lodge]

I have just read on the replication graph plugin. A thing I didn't really find though is if it's also helpful on fairly small maps with not that many replicated actors. Say, for example a shooter on a small map like in almost any shooter nowadays where there are only a bunch of replicated actors and up to 16 players. Mostly I have seen battle royale's, MMO's or so use it but just want to make sure

[kindred widget]

16 players is probably a good candidate for it. As usual "it depends™️" If your maps are compartmentalized enough, it could probably save a decent amount on not replicating half of the game to everyone all the time.

[ruby lodge]

Ah alright, thank you! As far as I understood, this doesn't replace any of the actual replication but instead is like a layer on top that checks who is relevant and who not, correct? Or will it be necessary to rewrite half of my multiplayer code lol

[kindred widget]

More or less. Basically if you have 16 players. You have 16 characters running around on each machine using normal replication. If you use the RepGraph, you can ignore the ones not actually relevant and not run checks on them until necessary.

[ruby lodge]

Do you know any good docs or tutorials on the RepGraph? The GDC vids I found were very old and mostly just explaining what it's for

[kindred widget]

I don't. I get the benefit of just poking at the stuff Kaos puts in. 😄 Sorry.

[ruby lodge]

Haha no worries, thanks nevertheless!

Last thing, so it's only for actors and used through giving them specific tags? So it's nothing about game states/widgets/playerstates/gamemode etc?

[vagrant grail]

I don't know what that means regarding my question

[twin juniper]

understood, so that also means that the hit effect can't be predicted?

[midnight palm]

Please help, I'm lost. It has been 3 days Im trying to find a way to replicated Quest3 users movement so everybody know where each other are in the map. The quests are conecting correctly to a dedicated server, but clients cant see each other position

I tought "Set is replicated" in the VRPawn would help, but nope

[crisp shard]

Are save games “safe”? Of course doing all save / load logic on the server but is there any issue with using save game files for player data in mp?

[kindred widget]

Nothing different than the issues you'll have using them in singleplayer.

[crisp shard]

i guess im more or less not aware of what the issues could be ?

should i be storing the data somewhere else ? i just dont want anyone to be able to mess w the files

[kindred widget]

Then you need a dedicated server of your own where players can't access the files. You cannot keep people from tampering with save files on their own systems. 🤷‍♂️

[crisp shard]

i am using dedicated server, but i was just made aware of the issue that if they reinstalled the game then it would lose their save game files

[kindred widget]

Like you are launching a dedicated server somewhere, or you're allowing users to?

[crisp shard]

im going to be using Edgegap so no user would be launching one

[kindred widget]

You should save their data with the server then. Client can install and uninstall all they like, they have no local data for themselves.

[crisp shard]

would simply just saving and loading their data "on server" like via an RPC that would suffice ?

[twin juniper]

I'm pretty sure the collision on the Predicted Actor on the Client still should work but not transmit data to the server to make sure that the visible part gets deleted when you've hit something..

Correct me if I'm wrong tho!

[kindred widget]

Don't really need an RPC. Data should stay on server. You have a dedicated server instance. The only thing the client gets is the data you allow them to see through replication.

[crisp shard]

yea you can do impact VFX/SFX on the local client and it won't effect the server, i think what he is suggesting is that you shouldn't do any predicted DMG or things that only the server should handle

[crisp shard]

hmm this semi confuses me, perhaps my logic is faulty (def isn't great hence my questions) but yea i am doing RPCs to load player data when the game starts on the character's begin play

[errant charm]

does this warning matter, it still works fine as it gets called on the server and multicasted

as long as it works right? doesnt cause any issues at the moment

[twin juniper]

😆 lol, it's not fine

try calling any RPC

Also, no need to blur for single names

[errant charm]

it works, it gets called on a interaction, this interaction happens on the client and server. so the server calls it anyways

but its not fine? so will it cause issues ?

[twin juniper]

surely something that you do not know is not working as it should

[errant charm]

is there any way to check if the client is calling it and not the server?

[midnight palm]

Im not sure to understand this error. What does it means exactly ? That it does not detect any client connecting ?

Its when Im launching the server

[twin juniper]

what do you think 'access none' means?

[kindred widget]

I'm mostly meaning that you shouldn't. You have a dedicated server. Save their data on the server. They log in, it's still there, you connect it via their net ID of whatever platform you're running through.

[crisp shard]

im using EOS, but im not sure how i would code that to save it on the server without a switch has authority node or "is dedicated server" and what class would i be doing that in ?

[kindred widget]

🤷‍♂️ Depends on when you need it saved. We use a save manager and when player's stats are updated periodically it'll trigger a save that gets the save manager and runs a save. We do listenserver so of course it RPCs that data back to the clients and they save it locally. But if we had dedicated servers running, the server would just save it all there without the RPC.

[cedar swift]

lots to unload with the last half of that. Where you save depends entirely on how you save, is it just automatic, after specific events? etc.
Important part is that the client doesn't handle the real data.
Client should request this data to be handled in some way and then the server to send them a notify (if necessary for login, visuals, etc.) with said data (you'd want this trimmed to only the necessary stuff and only a copy)

[crisp shard]

yea that all makes sense. currenty the saving a loading of this data is on begin and end play. both of which are ultimatley RPC's. the end play has a switch has authority but i made it a reliable server event as well. i do feel that i have the necessary checks in there (no client ever changes any important variable)

[cedar swift]

then if saving/loading still isn't persisent across different devices, it's because either the save data isn't working, maybe 1. you're not using something like a login ID to reference the save game 2. login ID is requested/saved before login, or this system isn't working.

I'd personally look at how you're storing the data and if there's any reference to your player's login ID when doing so & loading

[crisp shard]

so i haven't actually tested it in a real world condition w the persistent part. i just have been asking questions about it in different chats and got some interesting info regarding save files and potentially them being unsafe in terms of storing the data securely and cant be tampered with. as well as the reinstall the game thing.

but using EOS, they login in the main menu, validated through epic id, then that epic id creates a save game file (if they don't already have one)

if they have one, it will load the data

[cedar swift]

in simple terms, what you want to do to avoid save data not being safe is purely requests.
I attempt to login by pressing a button that sends my request to the server. Server sends me a notify with my loaded data if successful

IIRC, EOS can't have server side Epic ID specific data

[crisp shard]

i mean this is essentially what i have

[crisp shard]

not sure what this means

[cedar swift]

IIRC, with EOS you can't save a player's data from the server, the player has to call for it to be saved themselves
This part doesn't matter much to fixing your problem.
If they're able to load their data on a device normally, they're either saving locally, their data isn't being saved to EOS correctly, or most likely, they're not fully logged in before they're requesting their data.

Check your EOS developer portal and check Player Data Storage

I don't work with EOS anymore, so I'm sure things have changed and I'm not as familiar anymore, but it should put you on the right track.
Anyway, back to work, saw this between session

[crisp shard]

all good appreciate the help. was directed to the player data storage for eos so thinking by looking into it , it will spark the answer

[errant charm]

fixed it easy with Has Authority

[kindred widget]

You shouldn't need RPCs for this though. For any of it. The data exist on the server, solely. The server has events that run when a player is ready for play and lea ving the game which the server along can use to load data locally on itself for that player. It can locally use that data to initialize everything it itself needs. Stuff the player needs to know about can be replicated to it as state from it's varying gameplay classes which get and use this data on the server. Client has zero authority over the data, doesn't even have the ability to send in data to be validated. Anything you send the server from a client is subject to cheating.

[half umbra]

what's the deal with this PlayerState, when I add something like this to BeginPlay, the client has None, but the server doesn't

[kindred widget]

Beginplay of?

[half umbra]

how can I get PlayerState correctly? without using Delay?

[half umbra]

yes

in PlayerController

[kindred widget]

Why are you saving a ref to the controller in the controller?

[half umbra]

sry it is in component 😄

but attached to PlayerController

[crisp shard]

i get what you mean, and that is exactly what i want. im just not certain how im ensuring that those functions are only happening via the server without an rpc. and im assuming this is done via a server only class ? if you wouldn't mind i'd appreciate a small example of how that could work ?

[half umbra]

PlayerController >>> Component >>> Begin Play

[kindred widget]

The general answer though is that playerstates don't exist when a playercontroller is created. On the server your playercontroller and playerstate may be created before the server runs beginplays. On a client that isn't always the case.

TLDR never expect stuff to be available. You always code your networking to be adaptable to waiting for things to be ready or you hook into the functions where they're set and add delegates. Such as playercontroller's SetPlayerState

[half umbra]

what if I pass a reference to Player State to the client via Event (Run On Owning Client)?

because the server always has PlayerState, so you can just pass it to the client at the beginning of the game

or Not 😄

?

[kindred widget]

Might work, but it's risky. May work in normal conditions where the RPC takes just enough time most times, but sometimes that RPC arrives before the client has a playerstate, thus the server sends a nullptr.

Just code a wait, or hook into the SetPlayerState. It'll get to the client at some point. 🤷‍♂️

[kindred widget]

For example, OnPostLogin and OnLogout in your GameMode. They only run on server as they're in GameMode. Logout should happen on disconnects and intentional leaves, giving you a hook to gather data for that player and trigger a save.

[crisp shard]

ahhh now that clicks a bit more for me. that would be perfect

are those always called on logout for example?

in case of something like a rage quit or power goes out, server down etc

[kindred widget]

They should be. It should be called via the netdriver's timeout in most of those cases. At least for a client. Nothing can really help you if the server's power just shuts off.

[midnight palm]

@twin juniper Well, I guess it means it does not get players on the server ?

[twin juniper]

it means you are trying to do something like this:
nullptr->...

[half umbra]

@kindred widget In Player State (Component)

then you have a guarantee that Player State exists on clients

[kindred widget]

That should work. Assuming controller exists is pretty safe usually.

[crisp shard]

ok cool, yea appreciate the help using game mode to trigger these when players login makes sense to me so i'll try to adjust some things to use that and see where it takes me

[kindred widget]

For the record though. If you don't care about cheating. There is nothing wrong with letting the player upload it. Just from your initial point of caring about them tampering with files. 😄 They can't tamper with it if they never have it.

[half umbra]

But the controller always comes first?

[crisp shard]

haha makes sense, yea it's slightly "comptetive" so player stats / player currencies need to be not tamperable

[kindred widget]

The controller is what creates the playerstate in the first place. So when it arrives on the client, it will always be able to resolve it's owner pointer.

[sharp hamlet]

Hey all, anyone used this plugin called NetworkInformation?

https://github.com/Chippy4/NetworkInformation

This works fine, but not showing packet loss details even when the server is live in Gamelift servers. Anything i m missing?

[lost inlet]

this just reads the data straight off the player controller's netconnection

are you expecting there to be packet loss? if you have decentish internet it's not going to be a common occurrence

[sharp hamlet]

Well, in a dedicated server environment, during our playtest, i expected some users to show packet losses, but all of them showed 0 packet losses. Can this actually happen?

[lost inlet]

yes?

[sharp hamlet]

Mm, okay thanks

[sharp hamlet]

Last stupid question, if someone joins using a mobile internet, which is unstable or irregular, might he show some packet loss?

[lost inlet]

depends on the signal quality I would've thought

and in a static location I doubt it's that unstable

[sharp hamlet]

Got it

[subtle kernel]

hey guys. can you give me some basic idea of the work flow when you develop multi game server project? Like you have a client that travels from server to server, it's all nice and good in production configuration, but how do you actually develop/debug this process? Is it possible to actually do it in PIE? what would be best approach to simulate this behavior?

[crisp shard]

my server crashes everytime i try to run standalone mode while trying to load varaibles from an SQL database. this works fine when i play in editor but it seems the "server" doesn't have access/reference to the file that points to the database. im not sure if this is the case but would anyone know why this would happen in standalone but not in editor ?

ERROR: Failed to initialize persistence storage engine at path /Users/myname/Library/Application Support/com.MAiWORLD/iam-maiworld-default-rtdb.firebaseio.com: IO error: lock /Users/myname/Library/Application Support/com.MAiWORLD/iam-maiworld-default-rtdb.firebaseio.com/LOCK: Resource temporarily unavailable ERROR: Could not initialize persistence

[floral spade]

This sounds like an infrastructure error .. what are you hosting 'on' ?

[crisp shard]

im using google's firebase and im using a plugin to update it, but it works fine in editor, and it also works in standalone in the main menu, again guessing this is because when i am in the main menu, it's just local so the game can get the file that points to the database but on the server, i don't think it's able to

[floral spade]

Hmm, that actually sounds like a permissions issue - https://github.com/firebase/quickstart-unity/issues/807

a non-enterprise solution, should be to simply:
chmod -R 777 /Users/myname/Library/Application Support/com.MAiWORLD/

As long as the MAiWORLD is a trusted source, and not something you found on a usb drive outside your office..

and if that doesnt resolve it, you have multiple processes trying to acquire a lock on the same thing

you cant have that, so try to reduce it to one thing calling that LOCK file

[crisp shard]

hmm this might actually be it but not sure exactly. so you mean if im trying to get data multiple times at once ? i will try the chmod command

i did have prob like 3 or 4 "get data" things running off start so that may have been it

[floral spade]

So the basic idea is leverage as much debug information at your avail, to see what is actually going on.
I've spend many a year sorting through logs for errors and helpful details about what is going on where and why -- and the best approach, honestly, is to treat it as a game. You gotta hunt and 'find' the bugs and get them, squash them, or nurse them into 'features' =) but thats just my take on software dev in general

[floral spade]

that would definitely do it! on a POSIX system, a lock is a lock. Even the kernel cant do 'nuffin 'bout it anymore - its locked

[crisp shard]

damn alright cool. good to know. so basically make sure im only calling 1 at a time

[floral spade]

Yes, for a file-base 'backend' thats the only way -- you should look to a more robust solution 'if' you need it. You may not - it really depends on scale.

[crisp shard]

i had it setup to store a few variables on player profiles , like kills, deaths, their player lvls. although, im using savegame files as well, so it was more of a way to have the data be persistent and out of the game so i could have two places to check

[floral spade]

If you haven't already, add these to your DefaultEngine.ini while in development:

LogNet=VeryVerbose
LogNetTraffic=VeryVerbose
LogOnline=VeryVerbose```


But 'VeryVerbose' is the top amount of information, you probably dont need that - only 'Verbose'.

There isn't one single solution for debugging though. Learning the art of debugging your own code is something everyone does differently, in their own way.

And personally, I do a lot of pattern-matching - like I line two logs up side by side and look for the differences between stuff that way

[tired current]

Hey does anyone know the best way to ensure widget values are replicateed? Like if i have a healthbar, should I be setting the percent in from a repnotify on a health float in the widget? or should I be directly calling the setpercent method from an RPC in the owning actor for example?
I cant directly replicate user widgets it seems so I feel the owning actor is responsible for ensuring it gets displayed correctly on server and clients.

[quasi tide]

Widgets should just be reading from the game. So it should update based on w/e gets updated with where you have your health

[keen adder]

Make sure you use RepNotify (in the actor, which then updates the widget). Setting a replicated variable will make sure new players see the same health. Using an RPC only updates the one time, so newly joining players will not see the right health %, as they weren't around for that rpc

[dark edge]

1. Health float is replicated on WhateverHasHealth. Healthbar widget updates itself on tick or binds the value (same thing sorta) //Simplest and my default for quick and dirty. Fine for starting.
2. Health float is replicated (repnotify) on WhateverHasHealth. Repnotify tells Healthbar stuff. //gross, now WhateverHasHealth has to care about Widget.
3. Health float is replicated (repnotify) on WhateverHasHealth. Repnotify fires a Dispatcher which Healthbar is bound to. //Probably ideal. WhateverHasHealth just screams "Health updated" into the void and doesn't care who's listening.

[tiny pier]

I'm setting a mesh in begin play (after a short delay) in a custom AActor, however it only updates in the server. How do I get this to update on clients as well since RPC doesn't work on actors?

[neon summit]

Set the actor to replicate and check component replicates on mesh

?

[tiny pier]

oh it's cuz my blueprint version had comp replicates but not C++ version

[twin juniper]

So basically I'm currently using GetWorld()->SpawnActor on the server and it replicates to everyone automatically (it's one of those functions that does things heavily behind the scenes) and since I'm doing some prediction, I do not want to Spawn it on the owner... How would that be done?

In other words, I spawn an actor on the server and would like to make it replicate to some client but not all (not the Owner)

I could do a multicast on all clients and delete the spawned bullet on the client that I want but that would kind of be a waste of resources

[verbal ice]

You shouldn't predict this

[twin juniper]

I'm predicting a bullet, which is what most games do, right?

[verbal ice]

But if you really want to, you can override AActor::IsNetRelevantFor() and make it irrelevant for the owning player

Yes, but you should get rid of the client predicted one and replace it with the server's, if it's a slow projectile

Depends on your game I guess

[twin juniper]

like a fortnite gun

where most bullets are pretty fast

within 1 sec

[verbal ice]

Then you can use the function I linked

[twin juniper]

ok thx a lot!

[verbal ice]

Spawning a replicated actor per bullet might not be the best idea

But try it and see

[twin juniper]

yea someone told me that I could just replicate their location (FVector) but if it doesn't lag too much, I'll stay with what works easily

[spring venture]

Hi, I'm trying to build a hud for my game and I have an AmmoCount value that is OnRep'd. In the OnRep, I am trying to access the player controller so I can grab my hud instance and then settext(AmmoCount). However, I have found that it only works on the client and not on the listen server. I was wondering if anybody knew how to get the player controller of the listen server player?

[sinful tree]

Work the other way around. Have the HUD try to get the values it needs.

A good way of handling something like this is to use an event dispatcher that you can call in the OnRep, and you'd have your HUD listen for that dispatcher, at which point it can update itself with the new value.

[spring venture]

I see. Thank you!

[mystic crown]

How can set players in multiplayer game as target for enemy (nearest player set as target for enemy and if player run set nearest player as target again

[short arrow]

Are you asking how to determine the nearest player?

[mystic crown]

yes through AI Perception sight

[short arrow]

So you want to get all perceived actors, and determine which actor is closest to the owner of the AIPerception component?

[mystic crown]

yes and when player ran away AI select another nearest player as target

[short arrow]

https://i.gyazo.com/5428a9bfd896b7398975afd783af75ad.png

you should be able to zoom in to see it a little better

https://blueprintue.com/blueprint/vjhd1s8n/

posted it to there if you want to copy paste it, anyway to do the other thing you wanted you just need to call this function every second or so in order to continuously get the closest player

[mystic crown]

thank you so much

[mystic crown]

Thank you again

[mystic crown]

i can use this in update perception i think

[short arrow]

you can use it wherever you like, I'd just call it every second through a timer for simplicity but you can also call it on perception updated it should work just fine

[mystic crown]

ok thanks

[torn moth]

hey guys, a bit stuck on a problem. im making a multiplayer fps and my client is filled with errors while my server standalone works perfectly fine. whats strange is that the errors being thrown are regarding to references that im getting at begin play so they do register but then clear up on event tick with no setter there

[lost inlet]

some detail would be helpful

[torn moth]

this function is being called on beginplay. any code in event tick using this crosshair reference here says Accessed None trying to read property

[torn moth]

if i print it on tick this is what it looks like

my first time dabbling in multiplayer n im stuck on this for stupidly long so any help would be appreciated ;-;

[lost inlet]

well you only create it for locally controlled so that makes sense, so you would have to check validity, though I'm not sure why the crosshair doesn't perform that logic itself

[torn moth]

the logic of it didn't make sense at all but using validated gets only did fix the errors

[lost inlet]

well you didn't show the tick function

you tick other player's characters too

[torn moth]

oh. this was on tick but im assuming all of the errors were because it was trying to get references of the other player's components? which would explain why the validated get fixes it

asking solely for learning

[lost inlet]

why is it reading gameplay state from the anim BP?

and that's not going to be from another player

[torn moth]

no clue, I didn't make it which is why debugging is more hell than usual

[fiery wadi]

Hi can someone tell me why the client cannot open the door please ? I am trying to get my head round this but as I understand the Server has Authority and anything the server does automatically updates all connected clients, but if the client wants to do soemthing it sends the request to the server which then performs the "Execute on Server Event" to update the Door Actor in this example.

[kindred widget]

Your client doesn't own the door. It can't ServerRPC through it.

[fiery wadi]

@kindred widget Would i need to have 2 duplicate lines of logic one to update the client and another to update the server?

damn need to get my kid from school lol brb

[kindred widget]

You can only RPC through an actor that the client owns. So by default the PlayerController, PlayerState, or possessed Pawn. The usual action is to generically pass the door actor as an Actor pointer through some generic RPC to tell the server version of your Pawn or something that the player wants to interact with said door.

[fallen fossil]

Example:
Actor0 is owned by Server
Actor1 is owned by Player1
Actor2 is owned by Player2

Can Actor1 call event on actor0 to repliacte on server?
or I need Server Event on Actor1 and then call actor 0?

[upbeat basin]

Assuming you talk about perspective from Player1, you need the server RPC in this situation. It's not about from which object/actor you call the function from, it's about which client you call it. So in this case any server RPC will be dropped unless you call it from Actor1 on Player1 client

[fallen fossil]

I want just shortest path, calling from Actors 1 on client side, to actor 0 on server side

[upbeat basin]

The server RPC must reside on an actor you own. So you need to call Actor1::ServerRPC -> Actor0::AnyFunction to make your AnyFunction run on server

[fallen fossil]

rephrasing, I don't know if calling any event either its normal Event or "Run or server" is going to ServerSide and executed there.
❌Actor1 (ClientSide) -> Actor0 (pure event)
❌Actor1 (ClientSide) -> Actor0 (run on server)
✅ Actor1(Server side) -> Actor0 (run on server)
so I guess this only

i just forget how to do it hah

alto

?? Actor1(Server side) -> Actor0 (Normal event)

can the event be declared as normal? 🤔

[upbeat basin]

Well there is this distinction which might be important

• Actor1 (ClientSide) -> Actor0 (pure event) -> This will still run your function on Actor0 only on your client, since you're just calling another function
• Actor1 (ClientSide) -> Actor0 (run on server) -> This will not run anything at all, if you try to call a function marked as server RPC from a client that doesn't own the actor, it'll be dropped since you don't have the authority

[upbeat basin]

Yup that'll still run on server

[fallen fossil]

oki doki, I know all now

😄

thanks fren

[indigo brook]

Can someone explain like I'm five, how does one pass information to widgets? Example, player names.

I'm attempting to get player names (game mode) and distribute them to the player controllers then to the widgets they own. My results is that the names don't populate. It's server/client issues

[thin stratus]

You can probably just start from scratch on that

[indigo brook]

Agreed

lol

[lost inlet]

what is going on here even? game modes don't replicate for one

also player states already have the player name

and the game state keeps an array of them

[thin stratus]

• Replicated "PlayerNames" in the GameMode -> Wrong. GameMode is Server-only
• BPI_Multiplayer to call a function on the PlayerController -> Strange Design, just add the function directly and call it
• SwitchHasAuthority after a Server-only function call (cause it's coming from the GameMode) -> Makes no sense
• ServerRPC on Authority Pin -> Wrong. You are already on the Server. Redundant.
• ClientRPC on Remote Pin -> Wrong. Only Server can call that on a Client-owned Actor. You are on the Client. And in this case, this won't even ever call, cause of the Server-only function call
• Replicated "UpdatedNames" in a Widget -> Wrong. Widgets don't replicate. They are local only.

[indigo brook]

Thank you, I'll attempt this @thin stratus

I know widgets don't replicate, I also know the player states have the names...I think I am still not fully understanding the flow is all. I was poking around this and that. I don't think I fully understand how the server, player controller or things talk to eachother. I'm learning over time

I'm also viewing your compendium too

[thin stratus]

As sswires said:

• PlayerState has a PlayerName variable, already replicated for you
• GameState has an Array of PlayerStates, so you can easily access the PlayerStates
  • Note that they are not in the same order for everyone, if you need that you'll need to add your own, replicated PlayerState Array in the GameState and manage it yourself. The PlayerArray in the GameState is not actually replicated, but just filled by PlayerStates when they get spawned on everyone

[fallen fossil]

also small tip from me, call this on completed maybe , not each loop

[indigo brook]

Indeed, the goal was to get around casting to each controller, I figured this would work. It was experimental

[fallen fossil]

you can't destroy actor which is sending data right away ?

[blazing bear]

Is it normal to have lots of client corrections when looking around and moving in first person with 5% packet loss and 200ms? If the camera moves slowly, corrections rarely happen, but when looking around a lot and moving around, the client jitters and gets corrected. I wonder if GMCv2 does anything about it, or if players shouldn't be having 5% pkt loss in the first place

[verbal ice]

Players shouldn't have 200 ms and 5% packet loss

Do you have any custom movement code?

[verbal ice]

Also did you set the network emulation to clients only, server only or both?

[blazing bear]

Just sprinting built into a custom movement component, it jitters when packet loss is 5%, but say if I have 400ms and 1% packet loss then I rarely have jitters, and I don't get corrected by the server. The default CMC lags as well when pkt loss is 5%, yeah I think it's normal as the server doesn't even get the saved moves or something

[blazing bear]

Clients only, I also tried the commands on the client I'm testing on

[verbal ice]

How did you write the sprinting, custom move data?

[blazing bear]

Yep, I studied how cmc works and built it similarly like in this plugin #multiplayer message

the lag also happens when walking, though it's kinda worse when sprinting because the player moves faster I suppose

[verbal ice]

Yeah packet loss is exagerated with the network emulation

In real scenarios you'd rarely get loss

so I'd test with average settings, you can disable packet loss and see if it still lags around

[blazing bear]

Yeah that's what I thought, I think if players are getting high packet loss then it's kinda their fault

[verbal ice]

I generally test around 120 ms max and I don't expect it to be perfect all the time

Yeah can't make the game run smoothly for everyone

[blazing bear]

1% packet loss is pretty realistic

[verbal ice]

Generally less

But I don't think the network emulation allows for less

[blazing bear]

Even if I bump the ping really high like 400ms I rarely get corrections, aside from collision calculations seldomly which is normal

[blazing bear]

True true

Nope it uses integers iirc

[verbal ice]

I would just test with 0% pkt loss then in most scenarios, and then 1% for some more pushy testing

[blazing bear]

Alright then.

Thanks mate

[verbal ice]

o7

[crisp shard]

while testing in standalone recently i noticed that the camera and screen size are messed up. they are not represneting what i see what i just play in editor and the camera distance / FOV seems to either change or it's getting squished somehow

i dont know where the setting would be to change this but it's only when i do it in standalone; just playing in editor the camera / screen is fine and adjusts acccordingly. but yea standlone totally messed up size / ratio wise

[dark edge]

Player name should be a replicated variable in PlayerState

Already exists I think?

Anyways, whenever a widget needs a name it can just get it.

Say you have an outer widget which is meant to show a list of all players. It would get the playerstate array, and for each player, add a child widget displaying their name.

[indigo brook]

Thanks for answering, I got it to work through the Game State > Player Array > GetPlayerName. Works well enough!

[dark edge]

Yup that's the default name I was talking about

You can't change it from BP but can in C++

[indigo brook]

Though I'm still a noob with multiplayer, what I struggle with is the rules of communication.

RPC's can only be used by Player Pawn or Player Controller, or the "owner"
Store variables within Game State or Player State and Get or Set those variables from a Widget owned by the player controller
Add a IsLocallyControlled bool check to run things soly on a pawn or controller, making it client side

Am I right with that?

[blazing bear]

what is an "ack"?

my bad I asked too fast, it's acknowledgment

[void moth]

Hello, all. I've got a multiplayer test setup that works correctly if I have PIE run in Client mode where it starts a server in background, or in Listen Server mode -- in short, either mode where the sessions are pre-joined before my code gets control.

I've created a lobby level, session management widgets, etc., the way it's described in the official docs and numerous tutorials. If I start multiple players in standalone mode, I am able to craete a session from one of them, then have the others call FindSessions() to locate the server. That works perfectly.

Whenever one of the clients joins the server, though, the operation succeeds and the log shows all the network channels beign set up, but then the connection is aborted. Comparing the "working" and "nonworking" situations, it appears that the UDP port number which should be 17777 is somehow set to zero for my lobby setup. Since :0 is reserved to mean "assign a random unprivileged port number", I wasn't surprised at first when I saw this in the logs, but comparing to the working run, I think I should be seeing :17777 here.

I've checked project settings for UDP Messaging and TCP Messaging, but that 17777 doesn't seem to be something configurable there. Suggestions?

[void moth]

Correct. It's a term that goes all the way back to the days of EIA RS-232 serial ports and the dawn of the ASCII character set. There are specific codes for ACK (adknowledge) and NAK (negative acknowledge). There are, in fact, "Dad jokes" from very old IT people like me involving "NAK NAK" and the response, "Who's there?", and ... well, you know where this is going, so I'll spare you the cringe 🙂

Log entry (IP redacted) from my lobby session join bug:
[2024.09.24-20.57.34:217][213]LogNet: UIpConnection::HandleSocketSendResult: Socket->SendTo failed with error 5 (SE_EINVAL). [UNetConnection] RemoteAddr: 192.168.xxx.yyy:0, Name: IpConnection_3, Driver: Name:PendingNetDriver Def:GameNetDriver IpNetDriver_3, IsServer: NO, PC: NULL, Owner: NULL, UniqueId: INVALID Connection beginning close timeout (Timeout = 5.000000).

For the working test runs with the editor spawning its own server, 192.168.xxx.yyy:0 is replaced with 127.0.0.1:17777. I could make my TCP and UDP messaging listen on the loopback interface like that, but that obviously won't work with more than one device involved.

[blazing bear]

Hahahaha thank you for sharing that! Quite interesting.

[prisma storm]

hi, i would like to get some advice on improving and practices to avoid in the following code that allows receiving server data based on the TCP protocol.

void UGI_Game::Init()
{
    Super::Init();
    tcpClient.connect();
    GetWorld()->GetTimerManager().SetTimer(TimerHandle_Update, this, &UGI_Game::CustomTick, 0.01f, true);
}

void UGI_Game::CustomTick()
{
    if (tcpClient.ListenSocket && tcpClient.ListenSocket->GetConnectionState() == SCS_Connected)
    {
        uint32 PendingDataSize = 0;
        if (tcpClient.ListenSocket->HasPendingData(PendingDataSize))
        {
            TArray<uint8> ReceivedData;
            ReceivedData.Init(0, FMath::Max(1u, PendingDataSize));

            int32 BytesRead = 0;
            tcpClient.ListenSocket->Recv(ReceivedData.GetData(), ReceivedData.Num(), BytesRead);

            if (BytesRead > 0)
            {
                ReceivedData.Add(0);

                FString ReceivedMessage = FString(UTF8_TO_TCHAR(ReceivedData.GetData()));

                UE_LOG(LogTemp, Display, TEXT("Message server : %s"), *ReceivedMessage);

                GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Yellow, "Sent message: " + ReceivedMessage);

                TSharedPtr<FJsonObject> JsonObject;

                TSharedRef<TJsonReader<>> Reader = TJsonReaderFactory<>::Create(ReceivedMessage);

                if (FJsonSerializer::Deserialize(Reader, JsonObject))
                {
                    // Get the value of the json object by field name

                    if (JsonObject->HasField("type"))
                    {

                        FString JsonType = JsonObject->GetStringField("type");
                        if (JsonType == "connect")
                        {
                            if (JsonObject->HasField("id"))
                            {
                                FString name = JsonObject->GetStringField("id");

                                setPlayerName(name);
                                PlayerName = name;
                                OnPlayerNameUpdated.Broadcast(name);
                            }
                        }
                        if (JsonType == "join")
                        {
                            if (JsonObject->HasField("id"))
                            {
                                FString name = JsonObject->GetStringField("id");
                                FVector Loc = FVector(4349.f, 6129.f, 140.f);
                                FRotator rot = FRotator::ZeroRotator;
                                FActorSpawnParameters SpawnInfo;
                                AAnoPlayer *Player;
                                Player = GetWorld()->SpawnActor<AAnoPlayer>(AAnoPlayer::StaticClass(), Loc, rot, SpawnInfo);
                                if (Player)
                                {
                                    Player->PlayerName = name;
                                    PlayerList.Add(name, Player);
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

[thin stratus]

Yeah, you usually set a timer or the lifespan combined with a bDestroyed OnRep that can be used to make the actor invisible etc.

[thin stratus]

You can change it

GameMode should have a ChangeName function exposed

Don't ask me why it's in the GameMode

[thin stratus]

Yes and no. You are still throwing terms together.

ClientRPCs and ServerRPCs can be used on any Actor that is Owned by a Client. Aka the PlayerController of said Client is the Owner (Pin on SpawnActor node or via SetOwner function) of the Actor.

ClientRPCs can only be triggered by the Server and will be executed owning Client's Instance of that Actor.
ServerRPCs can only be triggered by the owning Client and will be executed on the Server's Instance of that Actor.
Multicast can only be triggered by the Server and will be executed on Everyone.

There is little side-note about Relevancy though. An Actor that isn't relevant to a given Client will also not have the RPC reach it. So a Multicast might not always reach everyone for example.

The Actors need to be replicated of course and only the Server can set the Owner, either via SpawnActor OwnerPin or SetOwner function.

Server triggering a ServerRPC will just act like a normal function. There is a chart in my Compendium that should list all possible combinations and what they end up doing.

IsLocallyControlled or IsLocalPlayerController are basically just two helper functions of Pawn and Controller that tell you if the Instance you call it in is the local one. You can do similar stuff in any Actor by getting the Owner. If it's a PlayerController then it will be null for anyone but OwningClient and Server. And then you can use IsLocalPlayerController on it. Some people also use other Actors as the Owner, cause up the Owner Chain they have the PlayerController as the Owner somewhere (PlayerController doesn't need to be the direct Owner).

These functions don't make anything Client-side. They only return true or false if you are on the Owning Clients side or not.

There is some more to it, but you should be able to read most of this in the Compendium anyway.

Putting replicated Information about the Game in general into the GameState and about each Player into the PlayerState is correct. Getting them in the Widget is also fine. Setting them from the Widget is a bit tricky. You'd need to have a ServerRPC in the PlayerState to set the replicated values there. And for the GameState you'd need to route the ServerRPC through a Client owned Actor first, cause GameState isn't owned by any Client.

[thin stratus]

Default Port is 7777 btw

Not 17777

[thin stratus]

Most people will probably ask you why you need that vs just using Unreal's Networking directly. So not sure you will get much feedback. Not a lot of peeps do what you are doing with UE.

[indigo brook]

Thanks for answering again, I copied this message so I can look back on it. I also watched a few more in-depth videos on networking using Unreal. There's some decent stuff out there which is good.

I just need to practice communication methods and tinker until it makes more sense. I'm going to study the compendium more as well. I'm at the phase in a learning journey where I learned a bit, tried some stuff, made some progress but now I need to hit the books again

[prisma storm]

The reason I'm switching to a custom version is mainly for the flexibility and total control. Although I know it's a bit more complicated.
After that, I'm not asking for code, but rather advice on what can be improved or avoided, as there's very little information on the forums.

[thin stratus]

Yeah and I'm basically trying to tell you that you probably won't find much more help here either, because most people use unreal existing implementation as that already offers enough control :/

If you go the route of custom socket connection you might as well look for generic information outside of UE

[twin juniper]

Did you create yourself tcpClient and tcpClient.ListenSocket ?

I'm curious about how would that even be done!

[drowsy pecan]

Hello, I have a question for all of you, if someone can help.
Is steam advance sessions with the SteamDevAppID=480 safe to share ?
like, if you create a server and some one join can see your IP or vice versa?

Is it safer for user to use the steam app id once its published ?
I just want to know if i make an auto host creation system for other to automaticaly connect to it. will it be safe for everyone?
Otherwise, is there a way to use Steam as a host to everyone to connect to?

Thanks

[void moth]

This is quite possibly the most concise explanation of the semantics of Unreal RPCs I have ever seen.

[void moth]

Thanks! I realized that some time after typing my question. When I looked back at the logs, what happened is that one of the truly random ports for the other end just happened in that run to pick 17777. It's been that kind of a day. 😄

[void moth]

This may be a bit more nitpicking than you really want, but I get a little twitchy when I see hardwired constants like "FVector(4349.f, 6129.f, 140.f)". I'm sure you know why, and I'm equally sure you're just prototyping, but it's really easy to let something done in prototyping slip through to later code. If you want it there for early prototyping, flag it with a comment. I work on Linux, and I'm in the habit of flagging things like this as "STUB" in all-uppercase, because a "grep -r STUB *" at the top of my source tree will find all of them. The all-caps tag also stands out if I'm hand-inspecting my code while cleaning up developer scaffolding.

[scenic horizon]

Hi all. Question about placing a replicated actor in the scene/editor. When the client joins, should it just work? Or is there any special checkboxes/considerations I need to make? (Using a listen server)

I'm having an issue where I have an Actor (NPC Character) placed in the scene that is replicating. When I place him in the scene I check a isNPC bool on the instance of the actor in the scene. I press play and the server starts, server player joins and can interact with the npc properly, npc moves around all good. The Outliner shows this scene object "BP_NPC". When the client joins, the "BP_NPC" disappears from the outliner, and is replaced by a spawned instance of that actor(With a default name, and the label is now yellow) with the properties I changed now reset back to default (so NPC = false now). And so, the client player can not interact with this NPC properly. What's odd is that the SERVER still can. Anyone have any idea lol? Is the Outliner just...not reliable? This should just work right? Feels like the client is saying "hey I have this actor in my local scene too, I should spawn it (even though I'm not the server?) and then things get confused or something? idk or something with AI controller posession?

[molten vine]

Hey! I have a question. I've been diving into the character movement component. And I've removed the mesh interpolation that happens to smooth out the teleporting between snapshots. And it worked fine. However, my camera, that is ATTACHED to the head of the mesh. Should just teleport and jitter with the character right? No... It smoothly interpolates.... (This doesn't happen on client, only on proxies) Something about the simulated proxies causes attached cameras to smoothly interpolate, instead of snapping to their correct locations.

[vapid gazelle]

Sanity check please: when I run the editor in client mode, I'm actually connecting against a dedicated server without a visual/cosmetic frontend, meaning that some code paths I assumed would always work when in Listen Server mode might actually not work.

E.g. Create System At Location (for Niagara) will not return anything because the dedicated server doesn't need to bother with it.

Which ultimately means I need to gate that path with a "Is Dedicated Server" check to not run into errors.

That sounds about right to you all?

[fossil spoke]

Yes, the very definition of Dedicated Server is without a visual frontend.

That is the difference between Dedicated and Listen.

[twin juniper]

It seems that when I spawn a weapon on a client and setting the owner to the controller (which shouldn't change the ownership to the server), it suddenly becomes on the server but it's still only visible on the Client...

[pseudo wagon]

When you spawn actor on client, that client will has authority with that actor, has authority will return true even it is on client.

[twin juniper]

To Remember: HasAuthority() checks if the actor we are in is OWNED by the machine we are on... if that instance of the actor is from the machine we are running on

[thin stratus]

It should just work, yes

Are you trying to Server RPC in that NPC by any chance?

[thin stratus]

Iirc the mesh interpolation is only for auto proxy on corrections in the CMC. The normal interpolation for the capsule is for the sim proxies. You might not have removed everything

[molten vine]

Hmmm, it's possible I didn't remove everything. But I literally searched for interpolation and checked all instances of it in the engine.

And the mesh and the capsule are at the same place. And moving in sync. The only thing is that when the character teleports to a new location, the camera lags behind.

That's the only thing that lags. I can even set the camera to follow the character. But the view still lags behind.

[thin stratus]

Did you set the camera to camera lag?

:D

[molten vine]

No....

It only happens in network replays.

I have no interpolation on anything to try and prevent the lag in the replay.

As network replays are incompatible with linear interpolation.

This is a super niche question. And the answer isn't in my code, it's somewhere in the engine. As replays don't work correctly by default.

[modest crater]

You poor soul you are still working on replays and snapshots 😦

[somber turtle]

In a multiplayer setting, is it possible to have the same pause behavior when a reward selection screen similar to the ones games like vampire survivor shows up ? I know you can enable pause on server from the client PC, but I am wondering if I shouldn't do that 🤔 and it might be a recipe for disaster.

I want to do something similar where each client need to perform action(s) before the game resumes for every one

[prisma storm]

The tcpClient is a class that contains connection information for now, and the ListenSocket is a variable that stores the pointer to a newly created socket via the CreateSocket() method of the ISocketSubsystem interface.

[prisma storm]

I understand that it can be frustrating to see this; it is indeed a prototyping version. But I assure you it will be changed anyway, as the position will be retrieved from the server to make the player appear at their last position before disconnecting. This was just to set a temporary spawn point.

[molten vine]

Yeah.... It sucks. I've tracked the problem down to something in the way that the engine moves scenecomponents. Making the camera move slightly slower than other primitives? Maybe tick groups, tick speeds? Maybe I need to run the camera's tick asynchronously? I have no idea.

[dark edge]

Authority and ownership are separate.

Clients own their pawns and controllers but do not have authority on them

[hybrid zodiac]

HI everyone, I have a really baffling problem that I can't figure out. I want to create a simple function that just returns a player's aim direction (i.e. where they are looking with their crosshair). Kind of like base aim rotation. This is my function:

FRotator ABSPawnBase::GetPawnLookRotation() const
{
    if (HasAuthority() || IsLocallyControlled())
    {
        if (GetController())
        {
            return GetController()->GetControlRotation();
        }
        else
        {
            return GetActorForwardVector().Rotation();
        }
    }

    FRotator Result = FRotator::ZeroRotator;

    Result.Pitch = RemoteViewPitch;
    Result.Pitch = Result.Pitch * 360.f / 255.f;

    Result.Yaw = RemoteViewYaw;
    Result.Yaw = Result.Yaw * 360.f / 255.f;

    return Result;
}

So the idea is if it's the server or locally controlled player, it just returns the control rotation. Otherwise, it returns a replicated view (I added RemoteViewYaw since by default it just uses the pawn actor's yaw which might not be the same thing).

HOWEVER, for some bizarre reason, if the function is called by the authority on a pawn which is NOT locally controlled, GetControlRotation() always returns 0,0,0. This function ONLY works if the pawn is locally controlled, or fully remote. I can't figure out why GetController()->GetControlRotation() is returning a zero rotator for the authority. Any ideas on why this might be happening?

[upbeat basin]

I unfortunately don't have an answer to your question but I'm curious why you are not using the base aim rotation directly, isn't that basically what you're trying to return there?

[hybrid zodiac]

@upbeat basin I believe the default functionality of base aim rotation returns the actor's yaw rather than the control yaw, which won't work for aim offsets where you want the body to twist to the left/right

[upbeat basin]

If your pawn uses the controller yaw they should be equal, isn't it?

[kindred widget]

It's more common to reverse rotate your skeletal mesh to stay in place.

In most game code, you want the actor's forward vector to be where they're looking. The lower half of the body is just faked in the skeleton animation.

[hybrid zodiac]

Eventually I want to use it for spectating a player driving a tank, where their aim rotation won't match the tank's facing

The actual problem I'm trying to solve right now though is that the host doesn't get the pitch values correctly when blending aim spaces: all players look like they're staring straight ahead

Basically, aim offsets currently only work for remote clients when observing the host

[upbeat basin]

Are your tank base and turret a single skeletal mesh or separated meshes?

If you're adding controller pitch input from your camera input, base aim rotation should be same across everyone including server, owning client and proxies

[hybrid zodiac]

I've not overridden AddControllerPitchInput at all

[upbeat basin]

No need to overriding, I meant just calling it with your camera input

I remember we struggled about the same thing (controlled pitch was not being replicated to proxies), we realized we were using get control rotation instead of get base aim rotation

I don't remember if there as another option that enabled it to be same across all players, but should just work out of box as far as I remember

[hybrid zodiac]

Not sure what that means. I have a first person camera which is set to use the pawn control rotation, but I don't think the camera runs any input

GetbaseAimRotation just uses the control rotation if there is a controller attached, so it has the same issue my function has: it always returns a zero rotator on the authority for non-locally-controlled pawns

We have an input mapped to mouse look which calls AddControllerYawInput and AddControllerPitchInput. Hmm... this would be executed locally however... I don't see where it's replicated to the server

Maybe that's the issue. Let me take another look

[upbeat basin]

The replication should be done under the hood by the engine as far as I know

[hybrid zodiac]

Yeah I just don't understand why the pawn actor rotates correctly, but the control rotation is always 0 on the server

I've never seen anything like it before

[upbeat basin]

Probably UserControllerRotationX is ticked on your pawn, which rotates it according to your controller rotation on everyone server, which is replicated to other players. But I don't understand why would you get 0 from GetControlRotation on server. That should directly return your controllers rotation on server and owning client

Are you sure it's the server that has 0 result?

That should be proxies who would get 0 vector from GetControlRotation since they don't have other players' controllers replicated to them

Are tanks changing their yaws with camera input directly and everyone is able to see that?

[hybrid zodiac]

Yeah it's definitely the server getting 0, and only for remote pawns:

FRotator ABSPawnBase::GetPawnLookRotation() const
{
    if (HasAuthority() || IsLocallyControlled())
    {
        if (GetController())
        {
            FRotator ControlRot = GetControlRotation();

            if (!IsLocallyControlled())
            {
                bool bBoop = true; <---- ControlRot is ALWAYS 0 here, and ONLY 0 here
            }

            return ControlRot;
        }
        else
        {
            return GetActorForwardVector().Rotation();
        }
    }

    FRotator Result = FRotator::ZeroRotator;

    Result.Pitch = RemoteViewPitch;
    Result.Pitch = Result.Pitch * 360.f / 255.f;

    Result.Yaw = RemoteViewYaw;
    Result.Yaw = Result.Yaw * 360.f / 255.f;

    return Result;
}

So my bBoop bool gets triggered if it's running on the authority, but the pawn isn't locally controlled, and it's the only time ControlRot is 0

[upbeat basin]

With a basic setup like this (with using AddControllerYawInput and AddControllerPitchInput) my server and owning client prints the same values while simulated proxies return 0. I don't have any idea how you're getting a different result from this sorry

[hybrid zodiac]

Yeah, doing the exact same thing as you produces this for me. Notice that weird first server value. It's actually showing -30 as the yaw, but it's frozen and never changes. That output is for the client's pawn

[upbeat basin]

That's still weird for me, you should get 0 for the servers pawn on the client if you're using get control rotation, it shouldn't be able to find a controller for that pawn

This is for control rotation

And this is for base aim rotation

Have you tried base aim rotation btw? Did you directly get into it with control rotation?

[hybrid zodiac]

Yeah, base aim rotation goes through a bunch of stuff, but if the pawn has a controller then it ultimately just retrieves the control rotation

So I end up with the same problem

[hybrid zodiac]

I made a mistake, re-ran it with the proper Get Control Rotation and the client now reports the host's control rotation as being 0, as expected. However, the server is still reporting a broken control rotation for the client pawn

The middle two values there should agree with each other, but they don't

[upbeat basin]

Is it a constant -30 difference even when you add rotation input?

[hybrid zodiac]

It sometimes changes when starting a new session, but it never changes after starting the game

Sometimes it's -59

[mint stream]

Is it a bad idea to call a server RPC from a UCommonUserWidget in a NativeOnButtonDown function?

I am trying to equip and item when I right click on a widget slot. The NativeOnButtonDown calls a server RPC that contains my EquipmentManager->EquipItem(EquipmentDefinition). But I am noticing that when the client right clicks the slot, it spawns the item into the world, but the server window never spawns the item so it's unable to tell other clients that it's spawned. Should I not be calling a server RPC from my widget Native function???

[dark parcel]

Widget is not replicated, you can't call RPC from there.
If you need client to call server RPC, you can route it to what ever the clients owns (Player controller or player's pawn).

e.g. Button clicked -> Get local controller -> buttonIsClicked (RPC)

[twin juniper]

But for instance an actor created on a Client, will have authority on that actor but the server won't, correct?

[dark parcel]

An actor created on client will only exist in the client.

The server won't even know that actor exist.

[upbeat basin]

In addition, if you check auth in an actor spawned in client only, it should still return true

[twin juniper]

the functions like Tick still runs on the server and client

[dark parcel]

Yeah but kinda pointless at the same time I think

[dark parcel]

If a client spawns locally, the server won't even know that actor exist.

You can test your self

Try spawning a banana in the client.

It won't show up in the server machine

[twin juniper]

I know, I'm basically doing Client AND Server spawning actor with the same actor, so the code inside of it must do some checks

[upbeat basin]

It's more about a warning that although it fails to replicate on everyone, if there is a logic that should work on server, it will still try to run on that client

[dark parcel]

Make sense

[upbeat basin]

Do you mean server and client calling spawn actor separately on their own machines?

[twin juniper]

yes

[upbeat basin]

Is your actor marked as replicated?

If it's not you're not doing anything related to networking here already. If it is, you are spawning an extra actor on your client

Replicated actors should be spawned from server only. Server will replicate the spawn on the clients on itself, you don't need to call spawn actor on the clients

[twin juniper]

It's a predicted actor

thus why it's spawned on the Client and Server

[dark parcel]

If it's a replicated actor you would probably end up with more copies than you want.

You can spawn proxy in client I guess and ask the server to spawn a replicated actor. When the replicated actor arrive in the client door step, remove the proxy

[twin juniper]

then when lagging, a client would see 2 bullets... when he would have shot once

I'm just overloading IsNetRelevantFor

[dark parcel]

Delete the proxy? But you would have to reconcile the difference when it comes to a bullet. As the one from the client will be ahead

For my case, I just spawn locally and hide the server's spawned one for the client that is locally spawning the bullet. Not sure how it will work when it comes to play testing, would be nice to hear how other people go with their projectiles

[twin juniper]

GetNetMode() == NM_ListenServer So is this an actual function to determine if we are on the server or not?

[mint stream]

So you're saying something like this doesn't work?

FReply UEquipmentSlotWidget::NativeOnMouseButtonDown(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent) {
  // Check if the right mouse button was clicked
  if (InMouseEvent.GetEffectingButton() == EKeys::RightMouseButton) {
    // Handle right-click logic, such as equipping the item
    EquipItemFromSlot();
    return FReply::Handled();
  }

  // Fall back to default behavior for other mouse button clicks (e.g., left-click)
  return Super::NativeOnMouseButtonDown(InGeometry, InMouseEvent);
}

void UEquipmentSlotWidget::EquipItemFromSlot() {

  // Check if the item is not already equipped
  if (!EquipmentInstance->IsEquipped()) {
    if (GetOwningPlayer()->HasAuthority()) {
      UE_LOG(LogTemp, Warning, TEXT("Equip function called from server"));
      ServerEquipItemFromSlot();
    } else {
      // Client: call the server function to equip the item
      UE_LOG(LogTemp, Warning, TEXT("Equip function called from client"));
      ServerEquipItemFromSlot();
    }
  } 
  else {
    UE_LOG(LogTemp, Warning, TEXT("Item is already equipped."));
  }
}
void UEquipmentSlotWidget::NetMulticastEquipItemFromSlot_Implementation() {
  if (EquipmentInstance && EquipmentManagerComponent && !EquipmentInstance->IsEquipped()) {
    // Spawn the equipment actors and set the equipment state
    EquipmentManagerComponent->EquipItem(EquipmentInstance->GetEquipmentDefinition()->GetClass());
    EquipmentInstance->SetIsEquipped(true);

    // Optionally log or handle UI on all clients (including the server)
    UE_LOG(LogTemp, Warning, TEXT("Item equipped on the server: %s"), *EquipmentInstance->GetEquipmentDefinition()->GetName());

  } else {
    UE_LOG(LogTemp, Warning, TEXT("Item is already equipped on the server."));
  }
}

void UEquipmentSlotWidget::ServerEquipItemFromSlot_Implementation() {
  NetMulticastEquipItemFromSlot();
}

Are you saying that my player controller should make a call to EquipItem instead

[twin juniper]

Pretty sure multicast in a widget doesn't work

[dark parcel]

no RPC will work in widget

it will just be treated as a regular function

[dark parcel]

sure thing, your widget job is to only read states, not to execute any game logic

[mint stream]

Ahhhh okay! I had a feeling that I couldn't do RPCs in a widget, but I wasn't 100% sure, so thank you for that clarification! I will move the logic to somewhere else. Would a UControllerComponent be a good place you think? Or should I just throw it into my player controller class? And I assume the variable bEquipItem should be a replicated variable inside whichever class?

[dark parcel]

I haven't work on my item or any interaction yet so maybe someone else can give advice when it comes to the design.
However, you can only run RPC as client on an actor that the client owns and by default, it's the pawn and their own controller.

Personally, I would route it to my inventory / equipment component but haven't work with components yet to know if RPC can be called from there.

[mint stream]

Hmmmm, I think components can call RPCs if they are "attached" to a pawn/controller. At least in my case, my components are attached to my pawn and some of the RPC calls work. So do you think I should just modify my EquipmentManager's (component) EquipItem to call a ServerEquipItem instead?

[upbeat basin]

If the component is on any replicated actor then the component can be replicated as well, thus allowing RPCs

Eh wrong message for reply

[dark parcel]

I noticed some multicast in your code though, what do you actually use them for?

it should never be used for stateful behavior

e.g. for equipping a weapon

[twin juniper]

why not?

[upbeat basin]

And for another perspective, I use inventory component as well as inventory item component, actors that have inventory component can be added to inventory array that resides on inventory component. I have a replicated InventoryComponent variable on my InventoryItemComponent with onrep function. So I check whether an item is in an inventory by checking the validness of the owner inventory variable, or broadcast added/removed events on the OnRep function to execute stuff related to state changes

[dark parcel]

Multicast = Server telling every client to run a function in the client's copy of the actor.

Now what happend to players outside Relevancy or players that have not yet joined the game?

they simply don't execute the code

so now you end up with joining players not seeing another player equipping a weapon that in their machines, equipped

95% of the time you don't want multicast imo

it's used by a lot of shit tutorial for the wrong reason imo

[mint stream]

Oh I didn't even think of that. I always thought it was the "route" to go for when you're trying to replicate things like spawning items into the world from a client so that all the clients can see and then the server calls the multicast to make sure it's replicated

[dark parcel]

If you want to broadcast a message and you don't care if it's get dropped, then sure multicast away.
You want to spawn a special effect but it's fine if they get dropped or not guaranteed to show on other client? Then use multicast

for anything that has to be in sync, you don't want to use multicast

most of the time, Rep-notify

[upbeat basin]

OnReps for the win

[dark parcel]

3rd videos I watched from youtube on multiplayer is someone spawning with multicast 🤢

and a lot of people thank him for the video

If you want to spawn an actor and have everyone receive a copy of the actor. You simply spawn it on the server (mark the actor as replicated). Then profit

Spawn Red Panda -> If Server -> Just spawn right away
If Client -> Run server RPC -> Spawn the panda

[upbeat basin]

Not using prediction from my case 🤡

[mint stream]

Hmmm gotcha. I will for sure keep that in mind as I progress forward. I luckily have been using OnRep functions for the most part so my code isn't riddled with a lot of that

[dark parcel]

spawning with multicast in this context, apart from being wrong, you end up with more copies 😄 😄

you get told by the server to spawn one locally, then the server also send you a copy

[dark parcel]

I tried that but unbearable even with little ping

Fireball comes out a second later 😢

[twin juniper]

if it's a solo game, then you are good 😆

[mint stream]

Thank you guys! I have something to work and I learned something new! I'm sure I'll have more questions if it doesn't work haha

[fallen fossil]

Does variables marked as replicated, are sent to server if modified by clients? Is it that simple?

[dark parcel]

it does not

changing the value on client side, will only change the value for it self

Unreal is using Server to Client model, and the only way for client to communicate with server is through server RPC

[fallen fossil]

ok

[twin juniper]

Why do people recommend that slow bullets shouldn't be predicted?

[twin juniper]

Also, for a flamethrower, that shouldn't be predicted, right?

[fallen fossil]

Do you know if replicated actors share same reference? I want to pass reference to "Heal" specific actor but other can executing event

cause I guess its true, im accessing none

I either can translate Actor reference for Server, or do logic on server side by player pawn 🤔

ok, it should work from owner->Pawn 😄

[crisp shard]

when i launch standalone for my game, the window size is extremely small and i dont know how to change it ? it also seems to be messing up the visuals, like it cuts off parts of the UI when in the laod in screen

how do i change this ?

it seems it's this, but it will not let me adjust

[ember jasper]

Hey,

If I Spawn an actor from the server with exposed variables set to a given value.
Clients copy of this actor do not receive the correct value.

Is there a way to receive these value as soon as BeginPlay hits ?

If I set the variable to Replicated or OnRep, there is a mandatory delay.

What would be the cleanest way ?

[upbeat basin]

You can add -ResX=SIZE and -ResY=SIZE parameters to your command line options to set the window size

[upbeat basin]

If you don't make them replicated there is no way of your clients knowing the value

I'm also not sure if replicated variables exposed on spawn works as intended all the time, I remember like we had an issue related to it and set the value after spawn instead of exposing but don't remember exactly what was the issue

Your best bet is having a repnotify variable and running your logic on the repnotify function

[crisp shard]

would this set the defualt standalone game setup? it almost seems like there is a setting that is "forcing" it to be that size, and when i adjust the size manually while playing the viusals are weirdly squished . really haven't had this issue

also, is that in engine command line ? not like the terminal ?

im on mac*

[upbeat basin]

Spawn and variable replication are not guaranteed to happen at the same time as far as I know (on cpp there is a PostNetInit() function that's being called when replicated variables are received after spawn/BeginPlay)

[upbeat basin]

Is it packaged game or are you using editor's standalone play mode/running from console or right click to uproject?

[crisp shard]

not packaged, this is just testing standalone game* play mode

[upbeat basin]

You should be able to add it on additional launch parameters under editor preferences -> level editor -> play (or click to advanced settings in the context menu (3 dots) near play button)

[crisp shard]

ok cool, this is the -ResX=Size / - ResY=Size?

i can't help but be curious why the play window would be squished at all still, i dont know why it would od that ?

[proud jewel]

Hi everyone,
I am building a multiplayer game. We build a dedicated server in go lang. I am trying to use unreal's protobuf from NNERuntimeORTCpu plugin. I am able to compile and run it in client end. However it is giving cannot parse wire data format error on the server. Any suggestions or information on how I can use it. I am using UE 5.3.2 and protobuf version 3.20.2 on the server side.

[grim rain]

Hi guys this function only works when i have the delay applied. is this okay to do in a multiplayer game or is there any other options

[dark edge]

what is the mechanic?

what are you trying to do

have a character carry another character right?

you have race conditions and redundancy all over the place. Think about it from the bare minimums

you should only have to send ONE thing to the server "I wanna pick up this dude"

so make your one run on server event just pass over DudeToPickUp, holding character is implied because it's you

???? -> I wanna pick up OtherCharacter (Run on Server Event)

RunOnServerEvent -> set variables -> attach

that might be enough, not sure if attachment plays nice like that with CMC

[grim rain]

this is the full code

yea to carry players

[dark edge]

that is pretty ludicrous, first off, figure out the minimum thing required to get the attachment to work

if you JUST attach on server, what happens?

I'm pretty certain attachment can be replicated already so make sure you're set up to use that

[grim rain]

if i do the attach on server only it doesnt work, rn it works with this set up with the delays idk how

[dark edge]

you might need to do some bookkeeping like turning off the CMC before attaching or whatever, but figure that part out first

You should not be multicasting anything here, I know that

[grim rain]

okay ill check properly, i turn character movement to flying in my set attached actor states function

[dark edge]

IF attachment has to be done on all machines (doubtful), at least make it driven by a repnotify

[grim rain]

thanks for ur help imma check and see if server only works

yea i would like other players to see players carrying each other

so i should go with rep notify?

[dark edge]

Try:
???? -> call PickUpDude(run on server event)
PickUpDude(run on server) -> set carried dudes movement mode to none -> attach to carrier

just that

[haughty ingot]

Attachment is replicated already, and it’s stateful. If you need custom logic when the attachment change happens, you can override OnRep_AttachmentReplication in the actor being attached to

[grim rain]

i did this server only way and it doesnt work so far

[haughty ingot]

Only the attachment is replicated.

assuming the attached actor is replicated

[quiet yarrow]

I gotta be honest. I think I have stumbled into something that helps my simulated objects physics to be replicated much smoother. But Im not sure what I actually did. Is anyone willing to take a look at my bp real quick and tell me what I did? Maybe I can do this same, but properly.

[quiet yarrow]

Here is what I did. Dont know how it really works tho. just sorta stumbled into it and now my physics feel more responsive on the client when I make contact so ive kept it

[twin juniper]

That is really not good...

You should understand the code before making it

[quiet yarrow]

lol yes I agree, but effort is better than no effort? idk I was just trying things

so what is happening and why is it sorta working as I want?

I have a general grasp on ownership and multicasting, but have no idea why this works in this context

[twin juniper]

You are making a Multicast on all clients to change the owner to the client Pawn, ok what if a new player join after that code has been ran? then they do not see that gun he's holding... or whatever that code does

[quiet yarrow]

right thats why rep/notify is a thing

tbh I didnt know multicasting works inside of a random actor

I thought rpc had to be made from controller or player pawn

[twin juniper]

for equipping a gun, I would probably tell you to Call a function that equips it on the server and then have a repNotify that triggers when it equips a weapon

[twin juniper]

I'd highly suggest to read this: https://cedric-neukirchen.net/docs/category/multiplayer-network-compendium/

[quiet yarrow]

So thats what I do with normal interactions with this. But since players could bump into it I wanted to be off of overlap. Setting the ownership to the person touching it just makes bumping into things that have physics be much smoother than not

[twin juniper]

can you test your game when a late player joins the game? see if that works?

[quiet yarrow]

Yeah it works fine. The items are replicated and match up 1:1 from all the testing ive done. So thats why im sorta wondering why this works so well

[quiet yarrow]

Oh I should add. Im using smoothsync with "Sync Ownership change" enabled

[subtle kernel]

guys, how to properly control movement by code when you have CMC on Character? It's kinda always tries to stuggle with what you doing. Even simple changing rotation doesn't work when it comes to replication. I'm really thiking about getting rid of Controller controlling the character and use AI Controller instead, which doesn't have this prediction issues, since in my game I don't really need prediction.

But still, if I want to stay with player controller on character and use CMC, what will be the proper way of controlling location and rotation programatically on the Character?

[uncut citrus]

Hey guys a quick question as I'm at a loss on this.
I have a dedicated server running a Ue4 map in 2 locations.
Is there anyway to know what Frame rate those maps are running at.
I set the server tickrate to 30 in the .ini file but I assume the real fps is quite different.

[lament flax]

For a large amount of structs to rep, whats the best between regular structs and instanced struct ?

[lament flax]

And are instanced struct dependant of the GT ?

[verbal ice]

Depends on how you replicate them

Instanced structs are useful when you want to replicate arbitrary structs

If you don't need em use regular structs

[fossil spoke]

In order for a Client to know the Servers frame rate, it needs to replicate that to the Clients.

[verbal ice]

Instanced structs are slightly heavier since they don't have delta replication, you always send it all

[lament flax]

Wdym with arbitrary structs ?

[fossil spoke]

@lament flax InstancedStructs are heavier from a bandwidth perspective than just replicating the underlying struct

[verbal ice]

Instanced structs are a wrapper for any ustruct

You can put any struct in them

[fossil spoke]

But you obviously lose out on the polymorphic nature of InstancedStructs

You pay a cost for that

[lament flax]

So if i got a ton of structs i should use instanced structs ?
But for a networking perspective i should use regular structs ?

Arent instanced structs very good for scaling ?

[verbal ice]

They have nothing to do with that

[fossil spoke]

"A ton of structs" isnt a reason to use ISs

[verbal ice]

Instanced structs are good when you want to hold "any" struct in a variable

[fossil spoke]

The only reason to use ISs is if you need polymorphic structs

[lament flax]

Instanced struct was mainly made for mass no ?

[fossil spoke]

No?

[lament flax]

Oh i thought it was

So if i dont care about modularity, regular structs should be good

[fossil spoke]

If you dont care about polymorphism in your struct types, then dont use ISs

[lament flax]

Okay thanks

[lament flax]

At runtime can you switch between net serialize and delta net serialize ?

[ember jasper]

Thank you very much, it works ✌️

I just precise I had to manage the server differently because the Server never execute OnReps if the value didn't change from its side.
Since the actor is instanciated with the correct value already, the Server sets its course through BeginPlay, ignoring OnRep.
Clients however won't go through BeginPlay and will only begin executing it after receiving the OnRep 👍

[queen escarp]

this might be a dumb question but im playing as listen server its abit laggy but on all clients its fluent, is it because my net cant handle it or is there any common issues for it ?

[upbeat basin]

There are several differences between BP and CPP OnReps/RepNotifies. If you're using OnReps (cpp) you need to call the OnRep function yourself manually after setting your replicated variable for the server

That way you can keep your logic purely in the OnRep function and avoid code duplication

I prefer to avoid setting replicated variables directly and use setter functions to keep assignment and OnRep call together, so I don't forget to add the OnRep on a random place where I set the value

[round mist]

Are you playing with simulated lag by accident? How many clients do you have connected? How much strain are you putting on the network with your game logic? Do you have a lot of stuff being replicated each frame?

[queen escarp]

not playing with simulated lag, about 3-6 clients dont have much being replicated each fram "i think"... how can i check the strain on network ?

[thin stratus]

What exactly is laggy for the ListenServer?

[queen escarp]

hard to say like "everything minilagging"

[thin stratus]

I don't think CPU should be a big problem with 3-6 players. There is the overhead of replication of course. Bandwidth could be an issue.

But if you only see the players lag then that's probably the same problem that UE has for ages with Simproxies lagging on ListenServers

[queen escarp]

hm.. i cant pinpoint the issue really i guess i have to record a session so i can narrow it down and maybe do some basic insight to se if it could be somethinge there

about the bandwith is there a way to allow more usage from it rather is there any built in max u can extend or something ?=

[ember jasper]

thank you very much for the precision Layso 🙂

I've got another question.

Is it possible to synchronize every player when they have a different joining time and therefore different GetTimeSeconds ?

I'd like an event to begin at the same time for my listen server and each of my clients

If they have a 2sec lag, a RPC or property OnRep will be called 2 sec later for my clients. They won't be sync.

[upbeat basin]

GameState has a GetServerTimeSeconds function that returns the approximate server time

[ember jasper]

WOW

Thank you very much ! Didn't hear about that !

[upbeat basin]

However it mostly have a bad reputation regarding to synchronizing it correctly. There are several tutorials/blogs about making it better

You might want to check this out and do further research on it if you want to be precise
https://vorixo.github.io/devtricks/non-destructive-synced-net-clock/

[ember jasper]

thank you so much 🤩

[lost inlet]

I keep hearing that but we shipped a game using it with a more frequent update rate

And since that blog post was written, they default update rate is a lot more frequent too

Since clock drift could be pretty bad with the default setting

[cyan marten]

Hi Guys,
I wanted to ask you guys what’s the best way to spawn 2 players in a different level after joining the same lobby.
I’ve tried a lot of different ways but they only works when i play the game level but not when coming from the lobby.
This is the code that i have atm.
The problem could be that between the lobby and the game level I have another level.
Thanks a lot🙏

[swift helm]

Hi, does anyone know how I can replicate network ? please

[sinful tree]

You'd use replicated variables set by the server when appropriate and then utilize those variables on the clients to drive your audio and visuals.

Seeing as you're using what looks like the vehicle movement component, I'm not sure if some of those values would already be replicated for you.

[swift helm]

Ok I will try to double check everything thanks

[indigo brook]

Question: If there's 4 players, (0-3), say client 2 gets hit, locally you update the character/pawns health (using a replicated health float variable). That replicated variable, it tells the server on change and each simulated proxy of the character's health variable gets updated to match right?

[silent valley]

No, only the server should change replicated variables. If client changes their own it is not replicated to anyone else.

[indigo brook]

Thanks for answering, so if the health variable is set to replicated, wouldn't it set it to the same as everyone elses version of P2 or Client 2?

[sinful tree]

No. Only the server replicates to everyone else. Setting a replicated variable on a client will only set it on that client.

[upbeat basin]

Server replicates values to clients. If you set variables in server, clients gets the updates. If you set variables in client, value only changes on that client

[silent valley]

A replicated variable, when set by the server, is replicated to ALL clients who have that actor.
So lets say Player 2 pawn has a health var, the server sets it to 20, then all clients can eventually see that Player2 pawn has a health value of 20.

[indigo brook]

Understood, so would this be a case for a Server RPC?

[silent valley]

usually a client would not request their own health to change due to cheating

[sinful tree]

Server RPCs are used by clients to send the server information / request the server to do something.

A health value changing isn't something that a client should normally be requesting the server to do.

[indigo brook]

I understand that and I understand that it could cause cheating. I think I'm just trying to wrap my head around the backend information sharing

[cyan marten]

Can you please help me with my problem above?

[upbeat basin]

I'm not sure if I get the issure there, are you trying to let 2 players play on different levels? Or are you trying to change your level from lobby to game map?

[cyan marten]

So i have a lobby level where the players join but then on the game level i’m not able to spawn the two players

What’s the best way to do it?

[sinful tree]

Variables are only replicated from server -> clients.
Clients can only send RPCs to the server, at which point the server can do whatever.
Damage being dealt isn't normally something you would allow a client to tell the server is happening. You at most would allow the client to say that they are attacking. The server would determine whether or not the hit was successful and then apply the damage which then replicates out to everyone else.

[cyan marten]

Sorry for disturbing you @upbeat basin

[upbeat basin]

Is the issue just spawning the pawns or carrying both players to the game level? You are using ServerTravel to open the game map right?

[indigo brook]

Thank you for taking the time to answer btw

So when a client's pawn gets in a fight and takes damage, what's the information flow?

[cyan marten]

I think the problem is spawning the pawns.
I’m using open level but i tried the servertravel but didnt change anything

I activated the seamless travel on both levels

could The problem be that between the lobby and the game level I have another level?

[upbeat basin]

Well there are several things that might be causing it

I'm not sure about this but I want to say open will close the client connections and open a new standalone level. That would make your clients to go back to your project default level game default map (on your project settings) while opening the target level on the caller only

Is that the result you're getting after attempting to open the game level?

[cyan marten]

No, every level is opened correctly by both client and server

They both open the game level

[upbeat basin]

In that case and if you are successfully travelling seamlessly, post login shouldn't be called on GM_Game. Because your clients are already logged in during lobby

[cyan marten]

I thought so

[upbeat basin]

After seamless travel AGameMode::HandleStartingNewPlayer_Implementation is called to let you know your player is there and ready to play. I think there is a BP version of it as well, considering it has the _Implementation postfix

Otherwise you might need to override it from cpp

[upbeat basin]

At least that's what I'm using to spawn my player pawns, there might be better solutions or earlier function calls

[cyan marten]

I have a example of HandleStartingNewPlayer in the image above, the thing is it spawns 2 servers

And i do not have controls/input on the server for some reason

[upbeat basin]

Well it might be due to the delay, clients might be taking more time than 0.5 seconds to travel

I would suggest avoiding using delays to ensure your logic in multiplayer

You can just check your player count after every HandleStartingNewPlayer call and start spawning once you reach the target count

And for that, you can use AGameState::PlayerArray which is a replicated TArray<APlayerState>. You don't need the custom player controller array

[quasi tide]

Client tells server it did an attack. Server does attack and tells other connected clients that the attacker did an attack. Processes damage on the server and tells client how much health they have (or if they missed or w/e).

Or the AI is what kicks all of this off and the flow is pretty much the same. Just, no client is telling the server because the AI is controlled on the server.

[indigo brook]

Thanks for answering, the server is the owner of the AI as well.

I got it to "work", I replicated my heath and healthmax variables, I also added a few Parent nodes after Begin Play and ApplyDamage events, now it works

[quasi tide]

Keep in mind, I don't know your specific setup. I did not go back and read anything. I was only answering the generic flow for games.

[cyan marten]

So i should leave my thirdpersoncharacter as the default pawn and no custom player controller?
Make the logic on the gamestate and gamemode?

[upbeat basin]

No I meant you don't need AllPCs array

[indigo brook]

All good, it's a listen server setup, I'm just trying to grasp the communication properly. I feel like I'm getting close-ish. You know how it is when learning multiplayer, take one step forward, two steps back until you actually understand it

[upbeat basin]

Because GameState already has AllPlayerStates kind of a thing. So you don't need to keep track of it manually

[indigo brook]

I've also been taking notes and trying to make graphs of information flow too haha

[cyan marten]

Is the logic in the image wrong beside the allPCs array?

[grand mica]

Has anyone tried to sync the clocks between different clients?
I want to actually start the match for both the clients at the same time but due to network latency there will always be some difference. To minimize that difference we actually add the delta for the clients depending on their Round Trip Time. Has someone tried to do something like this? Would like to know their experience

[sinful tree]

All that you need to keep in mind with this diagram is that the listen server host is acting as the server, and therefor has its own playercontroller, HUD and UserWidgets as well.

[indigo brook]

That's what I used to craft this one I made, I'm not saying mine is better or anything, just trying to understand it in a different way too

It's a great graph

[upbeat basin]

I'm not sure, there are lots of nodes that are not connected or not shown

[indigo brook]

I've been scooping up notes and infographics from a few places trying to understand it, doing cross referencing of other guides and videos too
@sinful tree

[upbeat basin]

I can suggest trying with disabling all your spawn logic and setting a default pawn to see if all players are travelling to game level successfully, then just spawning a pawn as soon as HandleStartingNewPlayer is received to see if they can get their pawns without synchronization and then checking player count on HandleStartingNewPlayer to spawn pawns to debug where your issue is at

[cyan marten]

Thanks i’ll try rn

[cyan marten]

Sorry for this stupid question, im still a beginner, how would you see if the players are traveling correctly?

If i put a print on the event begin play on the PC, when i start the game level it prints client and server but from the lobby to the game it prints server 2 times

[fiery wadi]

Ok im struggling with this after so many tutorials and "guides" and other information about "how replication works" I am confused to why if the server performs an interaction and the client see's it, I see people talking about "Client doesnt own the actor" which I do not understand to be honest with you. 😦 Its just so confusing for me at the minute. Any help is appreciated, Explain in laymens terms please xD

The server code

the door actor is set to Replicate along with all it's components to Replicate

[sinful tree]

Replication can only happen from Server -> Clients. In your example here, you're calling your "Interact" interface when you press the E key, but then within that interface, you're checking who the authority is of the actor, which will almost always be the server unless it happens to be an actor that you spawned only on that client, therefore, the interface does nothing more with that input when triggered on a client.

If you want the client to be able to call it, then you must send a Server RPC on your player's actor first when you press the input, and pass along a reference to the actor you're wanting to interact with. When running on the server, you can then call the interface to the actor that you're passing through the RPC, and then it would work.

You should also not need to cast at all when calling that interface - it kind of defeats the purpose of an interface if you're casting 🙂

[fiery wadi]

Ahh ok i think i understand Server RPC = Multicast or Run on Server?

[sinful tree]

Run On Server

[fiery wadi]

So if i make toggle door run on server should work ?

and remove the has auth node

[sinful tree]

No.

You have to call the run on server event on an actor that the client would own - which would be their controlled pawn, player controller, playerstate or any actor components attached to these actors.

Clients can only call run on server events on actors that they own.

So in your example here, you have your "E" input event which is probably on your character or player controller - it would be within this actor that you'd do the run on server event. The run on server event then can call the interface on the target actor.

[fiery wadi]

Yes its on the BP_ThirdPersonCharacter

@sinful tree Thank you for the advice, Would you be able to show an example of how this would work please? I tend to learn from visual things better, I understand if you cba tho 🙂

[sinful tree]

This is an extremely simple example but allows for communicating the E key being pressed and then calling the interface on the actor on the server.

[graceful flame]

@fiery wadi It might help to think of RPC (run on server) as an "upload" request sent from the client to the server asking for something to change. Then you can setup the server to verify that the request makes sense and isn't considered cheating and have replicate the change so that all clients "download" the new state. The other type of RPC (run on owning client) is like a "private download" that the server sends to only this particular client who owns the actor/character.

A multicast is like replication where the server broadcasts the changes to all connected clients with a single event but 9 times out of 10 replicating a variable is better because its more performant for the network to do. That being said sometimes you still want to multicast instead because replicated variables tend to arrive out of order.

Also a note on reliable. Don't use reliable unless its something that MUST not be dropped. For example a change in state that indicates that the arena has ended or that the boss fight is starting...etc. Sending too many reliable RPCs over the network can lead to a client being disconnected because they overflow a buffer. So for instance you never want to have a reliable RPC running on tick or bound directly to user input because if a client spams that input they'll just end up disconnecting themselves from the server.

[fiery wadi]

Thank you so much for the example, it's so hard to find clear concise information in a visual format because they use a lot of the technical terms which tbh do not make a lot of sense until you start using it in a practical scenario if that makes sense.

I understand the Multicast (Happens to all clients who happen to be connected at the time of the multicast (Latecomers will n ot receive this event))
Run on Server (This tells the server to do something) (Which is a little where my knowledge gets hazy variable changes on the server which are Replicated are automatically passed down to all clients, Repnotify's will also update the variable and notify Latecomers to the updated variable value)
Run on Owning Client (This only happens on the client who owns the actor) (I think)

Reliable - guarantee's delivery of the event/action but only use on pivotal game interactions which can cause game disruption (Such as Player hits, Damage, etc)

So i have done some of the "theory" behind it but finding practical examples demonstrating this in a "real world" scenario is quite hard. I understtand that my knowledge barely skims making a multiplayer game but I feel ity should be enough to make a game where a server/client or client/client can interact with the same object in different states.

@graceful flame Thank you for the information, And I understand of the "server checks" like if a player fires a bullet I need the server to check "Does the player have enough bullets to fire?" and ensure that the player has not changed their ammo count from 1 to 999999 or something similar, it's just trying to work out how it all works within a blueprint environment which is something that isnt very clear on the internet, I've seen a lot of videos which some use "Casts" and others are using Interfaces some will have 1 event which then fires off a ClientSide Event and then the ClientSide event will fire off a ServerSide Event and so it kind of leaves you in a state of confusion, I guess theres a lot of ways to do basic things in Multiplayer in UE which is why theres 101 ways to open a door in multiplayer and it makes it hard when you try to step outside of that "box". I really appreciate all of the advice and help!

[graceful flame]

This will help a lot: https://wizardcell.com/unreal/multiplayer-tips-and-tricks/

[fiery wadi]

Thank you I have bookmarked that and will go over it when my brain is a little less fried from all the multiplayer stuff and I do not have so many h ome distractions.

@sinful tree Would it be better to pass interactions from the PlayerController instead of inside the Character Pawn blueprint? I know when a player Connects to a session the server creates a PlayerController for the player and then spawns in a pawn for them (I think)

[graceful flame]

Either or is fine, but just know that the PlayerController can be used on multiple characters. So if you want to keep things a bit cleaner you can just setup the blueprint on the PlayerController with all the inputs to control characters once and make use of it on all characters. Just have to possess a character via the PlayerController to begin using it. You can access it from the "Get Controlled Pawn" node within the PlayerController.

[fiery wadi]

Ahh ok thank you I,ve been reading through this today as well https://cedric-neukirchen.net/docs/multiplayer-compendium/remote-procedure-calls/

[split siren]

Hey folks, I took a break from UE for couple of months, just wanted to ask in what state is Iris these days? Is it a bit more user friendly with some docs now?

[thin stratus]

Not to my knowledge

[indigo brook]

Quick quesiton, I'm attempting to hide the player's health bar on themeselves, but still see other characters healthbar. It works on the client as intended but not on the server, any tips? I'm using IsLocallyControlled with True setting the visibility to false, but it's not working, any tips? Right is server, left is client

[soft relic]

no need to use code for this

delete all, click on the widget component and simply check Owner No see

[indigo brook]

I tried that but it didn't work at the time, I'll try again

[soft relic]

Should always work, as long as you are not locally controlling that pawn, the component should be visible and vice versa

[indigo brook]

Aye, however, I disconnected the code as mentioned and set with Owner No See true, now they somehow BOTH see haha

[soft relic]

did you set that on the widget component?

[soft relic]

are you using any external camera actors or so?

[indigo brook]

Yes, the widget is a component of the Third Person Character...perhaps it needs an owner? I looked into changing owner but I got only locally controlled option for split screen

[soft relic]

what if you set that after begin play via blueprint?

[indigo brook]

No dice, I tried both these guys as well

The SetOwnerPlayer, ignore that hah

[soft relic]

you would set that to self or Get Controller I suppose, but im pretty sure I remember that working without setting any owners to components

can you play in normal pie mode?

[indigo brook]

Bhaha, beat you to it haha

[soft relic]

that would prohbably still not mkae a difference but worth a try, do try to play in New Editor Window as well instead of Standalone

[indigo brook]

Will do, on that note, when I play in New Editor Window, my client's screen is black

[soft relic]

thats something to fix then

[indigo brook]

It's a load order thing it seems

Maybe this counted for the black client screen but I had Absolute set to true, I turned it to false and my client worked fine

[indigo brook]

Super hacky way but I got it to work with adding a freaking delay in

[pearl saddle]

anyone know why voip doesn't work in shipped build?

actually when i tested it, it works fine in standalone for server. It also works for clients in shipped build (server can hear but cant talk back). It has nothing to do with my mic input as when my friend played as server it didn't work for him either and our voice worked when playing as client

[lavish junco]

Hi, sorry to interrupt, has anyone any guide or documentation about making an local only multiplayer game (split screen fps kind of) ? I'm struggling a bit with the spawning and respawn, and interactions between players (who use the same bp_character)

[lavish junco]

If it is for online multiplayer (on server or client server), the player index is no use, for what i tried to understand. This index is reference for the controller (hardware) affected to a playercontroller

[stable marsh]

Ran into another issue so just deleting my questions

[cyan marten]

You were right

[soft relic]

its not a node

you need to call it via console command

servertravel [LevelName]

[cyan marten]

I’m slowly getting to the problem

[cyan marten]

I was able to make the players travel to the game level, i only have a problem with a widget with a scenecapture where on the client it doesn’t show the background

[soft relic]

screenshot of code and what happens?

[cyan marten]

I will send it tomorrow, Going to sleep now

[stable marsh]

Alright, still stuck on this - server side the functionality works but I'm not sure I understand how to cast to the client. The server is the blue player, they click, they spawn blue units. The client is the red player, they click and spawn red units. Server sees the changes but client does not (even though they successfully spawn the correct unit).

[fossil spoke]

SpawnUnits is being called by the Server RPC, which means its only executing on the Server. So SetVectorParameterValue which sets the color, is also only being executed on the Server, which is why the Client doesnt see a change in color.

You should instead have a Replicated variable on the BP_Scissors that indicates what player it belongs to.

Then the BP_Scissors would update its color using that information.

[stable marsh]

So I already have a variable (unitMID) that is replicated in BP_Scissors. I'm not understanding the replication condition (I've checked through all of them).

[stable marsh]

(ignore the comment, I'm trying to test a derived unit before making changes on the base unit class)

[fossil spoke]

That doesnt mean that any changes you make to that are automatically replicated.

It just means that, that thing is replicated. Not changes you make to it.

Material Instances are not something you would replicate.

[stable marsh]

Okay thank you for the response. So would you recommend "Spawn Unit" dispatch another event which is called/listened on the unit itself - then put the coloring code in the unit (and make myPlayerIndexD a replicate reference)?

[fossil spoke]

Sure

[vestal pelican]

Is it possible to replicate a UObject and guarantee that 1 or more of its replicated variables are replicated before the UObject is considered as "fully replicated". The replicated variables may not necessarily be UObjects themselves (i.e. it might a replicated FString).

Example: Suppose the above UObject is replicated on an Actor and is hooked onto a callback function using ReplicatedUsing. When the ReplicatedUsing callback on the Actor is called for the UObject replicated, I am hoping that there is a way to guarantee that some data on the UObject, also replicated from the server on that UObject, is replicated and available when the callback on the Actor is called.

[fossil spoke]

You should never try to make this type of assumption. You will always run into issues.

If you need certain data to be available together, pack them together and send them together.

[vestal pelican]

In this case it's not exactly possible because I have a replicated object that I have a callback on in a different part of the code. I can't pack the pointer to the object and the starting data and send them together unfortunately. It resides on the replicated object only.

[verbal ice]

No guarantee possible

If the replicated data on UObject is POD you have the guarantee that it will be available when that UObject replicates for the first time on a client. If it has already replicated you have no guarantee that it will be available when the actor's reference to the object is replicated

Since you can't really guarantee it's the first replication in your scenario, yeaaaaah

For actors you have the guarantee that, in BeginPlay, all replicated properties (that do not require mapping to another UObject) have been replicated.

Note: they may have been replicated but the rep notifies may not have been called. They tend to fire before or after BeginPlay.

[stable marsh]

What am I missing with this replication stuff? I've replicated the int that drives the selection choice but it's not updating on the client. Also, the color behavior is also on the unit now, instead of the player controller.

[somber turtle]

Are you modifying the int on the server?

[stable marsh]

Is this a server event? This is what modifies the index

[verbal ice]

Yes

[somber turtle]

Yes because the GameMode only exists on the server

Depending on your flow, it's possible variable hasn't replicated yet

Hard to tell from the images alone

[verbal ice]

Use a replicated property w/ notify

[somber turtle]

If you want to validate this, you can use a rep notify and break point in there

[verbal ice]

Use the rep notify to change the color

[stable marsh]

I assume I would do it here - but I don't see the "Set W/ Notify" node when I search for it.

[somber turtle]

In the details panel, instead of choosing Replicated choose the option with notify

[somber turtle]

It will create an associated function

[stable marsh]

Huh, now I'm having the opposite problem - only client updates the colors

[verbal ice]

Did you update the node to Set w/notify

[stable marsh]

Alright got it working but this seems incredibly wrong:

I have to have both functions. If I just put it on init unit, only the server updates. If I just put it on the notify function, only the client updates

Is that correct, to have to duplicate the functionality across two different functions?

[quiet yarrow]

First time doing seamless travel. I've read through the blog post about seamless travel and I cant seem to get my clients to move with me. Anyone care to help?

[fossil spoke]

You literally just set EnableSeamlessTravel and use the ServerTravel command.

[quiet yarrow]

servertravel command?

[stable marsh]

Anyways, I'll mess with this more now that I know about RepNotify. Thanks all

[fossil spoke]

The Server must switch the level.

[quiet yarrow]

I am switching on server. Im just using open level by object ref

this?

[verbal ice]

Not really

Check that your Set node is now Set w/ notify

Or just have the on rep call a function that sets the color

that way you can just call that function manually when you set the index

instead of duplicating code

[void moth]

I have a general concepts question. In UE, an RPC ius an Event, and it can accept inputs but doesn't return anything. This isn't the only way RPCs can work, however. In many other programming environments, an RPC is literally just a function call that traverses a network socket. The flow is something like this:

1. Caller invokes the RPC thunk on the initiating system.
2. RPC system serializes input parameters and marshals them into network transaction, then passes that transaction payload to target.
3. Target system receives RPC transaction request and parameter payload.
4. RPC system on target deserializes input parameters and calls the function implementation.
5. Function does the requested operation and returns its values to the RPC system.
6. RPC system serializes return payload and marshals it to network transaction response.
7. Network response payload reaches caller.
8. Caller's RPC system deserializes return values.
9. Calling thread is reawakened and receives function return values.

All of this presumes the RPC call happens from a thread because it will block until complete or timed out.

My question: Is there anything comparable to this in UE?

The closest implementation pattern I can discern would be to call a server-side RPC to get the input payload to the server, then have an expectation that the server will set a predefined replicated-with-notify variable (maybe a struct). The caller treats the OnRep_Foo event as an async function return.

Is there a better way?

[thin stratus]

UE doesn't have an RPC that handles the return. You can call a ServerRPC in combination with a ClientRPC to mimic that fwiw

ClientRPC vs OnRep is more a question of the data being a state change or not

[quaint rain]

I bought a Steam plugin and it's storing the Steam web API secret key in the DefaultEngine.ini.

How insecure is this? Can clients access that INI?

[verbal ice]

Yes

That's very bad

[peak mirage]

Can anyone help me, what is the problem with Network Prediction Plugin? I saw a lot of blog posts say it's a must for multiplayer, while others (mostly here) said the plugin is not good or even causing a lot of trouble.

Currently considering between 2 prediction solutions, so I want to know what problems NPP has before making the call

[verbal ice]

What do you need it for

[peak mirage]

Well, I am working on an action fast pace game so prediction is a must.

I do know what prediction is and how it works, just too lazy to write one while there are many well know solutions around

So I want to know opinions from people with far more experience than me

[short arrow]

you probably won't get the response you're looking for here as people would actually have had to buy it in order to tell you why it sucks. I can say for certain the "movement prediction" plugin I bought once on the marketplace was indeed shite and our testers hated it. We removed it within hours even after reading over all of the documentation and believing we implemented it properly

Most code related things on the marketplace are pretty shit to be honest, I don't even bother anymore unless it's free. Especially if it's made in blueprint only. Hot Take: People who actually know what they're doing aren't wasting their time making youtube tutorials or marketplace assets. They are likely writing articles on a their own web page or documentation page, and releasing things on github or some equivalent

[fallen fossil]

Does multiplayer gamestate and mp gamemode is good for singleplayer? I want to do SP / Coop, so I should use mp version, but was thinking its usable for SP

[short arrow]

You can use them both for singleplayer without consequence, gamemode is not made for multiplayer use at all.

[short arrow]

Gamemode is not made for multiplayer use in the sense that it does not replicate

[peak mirage]

@short arrow well looks like you misunderstood me. I am asking for opinion about Epic's free Network Prediction Plugin, not some random plugins on marketplace. Thank you for the opinion anyway.

[short arrow]

Gamemode, the child class of BaseGameMode has some functions that help with multiplayer, but it itself is not made for multiplayer

[short arrow]

they made a prediction plugin?

interesting

[peak mirage]

Yeah, about 5 years ago actually

Cedric had talked about it here as well. From his experience, thing doesn't work as smooth as one would expect

That was the first time I see someone has a negative review about it, so I decided to ask people for their opinion

[short arrow]

thanks for letting me know, had no idea. I'd imagine it's one of those things they stopped working on in favor of Iris

I know Iris is planned to make a few multiplayer plugins obsolete

Gonna look into that 😅

[fallen fossil]

Ok thanka

[peak mirage]

From what I know Iris is the layer below that and have nothing to do with prediction so I don't think it will make NPP go anywhere. On the other end, RepGraph doesn't look so well...

[short arrow]

right but they said something about wanting UE6 to be able to replicate hundreds/thousands of players easily I think, and I can't imagine them achieving that without some kind of prediction system? Unless the engineers are just built different and won't need it

[nova wasp]

Iris is more of a replacement of how packets are formed relative to changing properties on objects... it makes stuff like polling for changes and filtering faster/different but it has no bearing on game code performance (and not even really how unreal works, it's mostly seamless)

it doesn't even know what uobjects are without a wrapper around them that's added on top 😛

I think it's certainly a step in that direction but definitely not "zomg I can make mmos now" by any means from what I understand

[queen escarp]

hey

at the end of a actor (projectile)

when its colliding i destroy it but if i do it instantly it dosent have time to play sound (so no sound is played) if i put a delay it works but the obviously the actor still exists wich looks super wierd

whats the common way to tacle this ?

[vocal juniper]

Hi guys
I have some topics to learn about replication in Unreal, but i write it from telephone call so some naming is't right
Does anyone know somesthing about it, or maybe you now some good resources where i can read about this
Topics:
-blob's
-relational bias
-prediction
-relational motion serialization and addressing
-wat vamp
-spotization
-jointry collection
-red point
-api for shells

I know that sounds stupid but any information will be hapefull

[silent valley]

I mean... I don't know where to start. What is it you're actually trying to do?

[vocal juniper]

I can describe my situation
I'm looking for a job for a bout a year now
And one guy told me to learn Replication deep, and create a project focused only in replication
I can't find any information while google "spotization" for example
I found some information about blobs.
i don't actualy know what is wat vamp, jointry collection, red point, relation bias, relational motion serialization and addressing

Maybe someone know good blog about deep replication behavior stuff like that

[silent valley]

ok, I'd suggest don't worry about that, you should try and make a multiplayer game. follow through some tutorials perhaps, and along the way you will learn about 'replication' etc.

if you spend a few months on this it should eventually 'click'

[vocal juniper]

i already fineshed Tom Looman Course
And i have an experience with basic replication, and refactoring some base components logic to be replicatec
But i don't actualy touch any blob's and prediction in it

[silent valley]

I mean a 'blob' is usually just sending a large amount of binary data - not relevant for most games.
Prediction - the CMC which handles player movement already has a lot of prediction built in.
If you want to practice prediction, try and make a projectile that you can fire from a client and it feels responsive and looks smooth for all other players.

IMO, don't try and learn concepts without actual context.

Learn 'how to learn' efficiently instead 🙂

[vocal juniper]

I understand. thx for the reply

[short arrow]

great explenation! in that case I wonder just what epic is planning for UE6. They certainly have the goal in mind for massive amounts of players being possible without much effort beyond proper code ethics, and optimizing. Perhaps they are planning to come out with some unreleased things that will work alongside Iris? Or maybe they are just making big claims that will never fruition.

[tight lava]

Hi, I'd like to see if I can add multiplayer to my vr game, but I don't really know where to start. There are a lot of tutorial on Yt, but I wonder if it all work even with VR, and overall the amount of stuff is a bit overwhelming 😅
So um, what should be a good beginning for that ?

[cunning orbit]

Yes, all of the same principles apply so just start with learning MP mechanics without adding the complexity of testing with VR

[thin stratus]

You can use it for Multiplayer and Singleplayer just fine.

Ah, chat didn't scroll. gg.

[tight lava]

Alright, I'll check that myself but more reassured, thanks !

[rustic sable]

how do you go about passing commands to a dedicated server, say you may want to change some behavior at runtime or call a quit command. Any guides on this?

[fossil veldt]

Do yourself a favour and go and use Mordentrals VR Expansion Plugin

[short arrow]

Are you talking about Server RPCs?

[rustic sable]

well this wouldn't be coming from the client, thinking more like console commands

[subtle kernel]

guys, how do you solve issue with data management in MP? I mean sometimes you have your character blind for example, thus it shouldn't be receiving data that he is usually receiving when his vision is on. On what level of abstraction this should be managed?

I'm talking basically competitive MP games, where possibility of seeing through the fog of war should be as little as possible.

[short arrow]

If you're trying to send information to a dedicated server from outside of the game then I imagine websockets is the best way.

I don't think unreal engine offers an actual terminal you can use to input console commands into a dedicated server

[rustic sable]

ok I thought if I have my server instance running on linux I could just pass cosole commands into it but if that's not the case I'll try it with websockets

[short arrow]

I know you can do it with websockets, but I feel like you should be able to do it with a Server Command Line Interface... I just have never seen anyone do it

[wanton bear]

Assuming i need packets to arrive in order but i dont care about packet loss, the best way would be to just send a sequential number with each RPC and discard older packets?

[dark parcel]

@short arrow Wdym by Game mode is not for multiplayer 👀

[short arrow]

is not only for*

I see the problem is me, multiplayer and replication are not the same thing. I should have phrased that better

[dark parcel]

Game mode only exist on server, it have some functionality for multiplayers that server can utilize.
E.g. When a user joins (Post login) and when a user leave

you can use that as a container to hold data for the server too that others don't neccessarily have to know.
E.g rules of the game, how many bots , etc

[wanton bear]

alright gonna assume im right

[short arrow]

Your question is a little confusing, it's impossible to guarantee the order rpcs are sent without making it reliable, in which case not caring about packet loss means nothing

You can heavily increase the chances that the order will be correct, assuming you never saturate the available bandwidth for that frame or whatever the term for it is

[wanton bear]

the order theyre sent remains the same i.e. packets arrive 1, 3, 4, 7, 6, 5
theyre labelled as such so it turns into 1, 3, 4, 7 where 6 and 5 are discarded and the ones that didnt arrive dont matter

[short arrow]

And also never sending multiple of those rpcs over the same frame

If you are testing locally and the there's no heavy load then things are almost guaranteed to be in order

It's when saturation happens, and things start slowing down, that things start to happen in an unpredictable order unless the rpc is made reliable

I wouldn't test something like this locally

[wanton bear]

right... and if the client sends an incremental number with each RPC...

you know you can emulate ping in unreal right

and packet loss

[short arrow]

I don't think it's ping that determines this. The order that which rpcs are sent out and received are just not guaranteed. I've never actually read the code myself, but I remember unreal being pretty clear about this

It will most likely be in order, it's just not gauranteed

Unless it's reliable

[wanton bear]

...

[short arrow]

Something about UDP protocol being cheaper, but pretty much gaurantees nothing. It could come sooner or later, out of order, or straight up not at all

It's not really tied to ping

[wanton bear]

ok. the order is guaranteed (not the arrival) if i send an incremental number with the packet. i was more asking about whether its the most efficent method or if theres a built in method for what i was trying to do so i dont have to manually send the number and store it.

[fierce egret]

I cant figure why does Print get called on Server. Any help?

Character is client, not server

Tried this, still server prints

[wanton bear]

event beginplay runs on the server and client. if you imagine both the client and server has a copy of the character, and each one owns their copy. i believe that's why it prints twice

[subtle kernel]

what do you play in PIE?

[fierce egret]

Client mode

[fierce egret]

How can i make it print on client? Is there another way?

[wanton bear]

event beginplay -> is locally controlled branch

should do what you want

[subtle kernel]

what is this thing you implement blueprint in your screenshots?

[fierce egret]

I want it to send a message to the client after certain actions are done on the server, not at BeginPlay. I don't think it will work for me :(

[fierce egret]

Its a replicated actor component. My character has this component

[subtle kernel]

Are actor and component replicated themselves?

[fierce egret]

Yes, checked many times

Now i created a new replicated actor component, pasted nodes, added it to character, still same

I cant understand, i'll try it in a new project

[subtle kernel]

How do you create actor? Just drop it into the world?

[fierce egret]

Automatically spawned, on PlayerStart

[wanton bear]

make sure youre only sending from the server, then multicast RPC with a "islocallycontrolled" branch

[fierce egret]

I did this, is locally controlled returns false always

I didnt try it with multicast, but is it a good solution? I mean using multicast to send a message to specified client

[dark parcel]

no

just avoid multicast

for anything stateful

Anyway, I run some test

Begin play is too early, the client's actor is not owned by the client yet

Doing this, will print on server only

but if you add delay it will print Client

[fierce egret]

Holy, that worked

You are right

[dark parcel]

so my guess is that, begin play is too early, the actor is still owned by the server

[dark parcel]

well you don't want to do it this way

[subtle kernel]

you need to use some onrep_notify to make sure that client owns actor?

[dark parcel]

initialize on Pawn Possess instead of begin play

[quasi tide]

Put in a 40 second delay. If the network stuff hasn't resolved by then - you have far bigger problems anyway 🧠

[fierce egret]

Makes sense, thank you

[dark parcel]

RepNotify just gets called whenever a variable value changes

[fierce egret]

By the way, does repnotify trigger when client attempts to change value of variable?

Or should server change it?

[dark parcel]

it gets triggered whenever the value changed

[fierce egret]

So it wont, if variable is replicated

[quasi tide]

It operates differently in BP and C++

[wanton bear]

server should change it, but i think if the client does it just triggers for the client right?

[quasi tide]

In BP - onrep is always triggered. Even in singleplayer games.

[dark parcel]

well if the variable replicates the value will be updated so yeah it will be triggered

[quasi tide]

In C++, you have to manually call it on the server

[dark parcel]

yes but that will still trigger the rep notify

who ever change it don't matter, it will be triggered

[wanton bear]

ooh i could ask you summer, is there a built in way in bps to make sure rpcs are received in order but without care of discarding packets or whether they arrive

[dark parcel]

not the right person to ask sorry

Thought moxie already talked to you about it

[quasi tide]

The answer is no

[dark parcel]

he is 1000X smarter than me

[wanton bear]

right now ive set up so it sends an incremented number and discards any that are before the last number received

[quasi tide]

Your only choices are unreliable and reliable - and neither fill your requirements

[dark parcel]

someone mention that if an RPC is reliable and if the RPC come from the same actor, the order are reliable? 0o

[quasi tide]

Look at the rest of his statement though. He wants it in order, but without care of discarding packet or if they even arrive.

Order isn't the only requirement

[dark parcel]

ohh okay

[quasi tide]

He wants the order of reliable but the rest of unreliable

[wanton bear]

reliable is a lot of overhead. just gotta stop bein lazy and do it manually i guess

[dark parcel]

What is it for btw? curious

[wanton bear]

just a coop movement system, so if you change speed to go faster and then slower and then faster rapidly and the packets arrive in a random order itll just throw away some instead of trying to show it accurately and waste resources

[dark parcel]

I would probably just make the rpc reliable and if I hit bottle neck then re-think the approach

[wanton bear]

that makes it massively slower though when you dont really need it?

as long as the last packet was the correct speed then there shouldnt be any rubber banding type issues i think

[dark parcel]

not fammiliar with the overhead but is it something that you already experienced?

[wanton bear]

well if reliable needs to wait for the right packets to come it could make it extremely slow

if you have 100 ping and send 2 packets, the second arrives first and the first doesnt arrive at all then the server has to send a message saying it didnt arrive and then you have to send again, probably making it 300ms bottleneck?

not sure if theres some sort of step im missing in the middle there that would make it faster but i think that's somewhat accurate as to what happens

[dark parcel]

probably want to take a look at how CMC does it.

delgoodie makes a nice video on how it work. Client apply movement -> Send the movement data to server -> Server validate and apply correction (if any)
there is some degree of tolerance as well so you only get rubber band when the network is extremly shitty.

[blazing bear]

how are you changing the speed of the character? using rpcs?

[blazing bear]

no no, have you tried having movement-safe variables in your custom UCharacterMovementComponent class and override the GetMaxSpeed function to return a different speed based on those variables?

you need client side prediction

as ColdSummer said, delgoodie does have a great series on this topic

I have done a similar thing not long ago and it works even with 400ms and 1% packet loss

[wanton bear]

hmm okay i bookmarked the youtube playlist for later thanks

[blazing bear]

np, even the first three videos are enough to get the hang of it, good luck.

[subtle kernel]

can you drop me a link please?

[blazing bear]

https://www.youtube.com/watch?v=urkLwpnAjO0&list=PLXJlkahwiwPmeABEhjwIALvxRSZkzoQpk

[dark parcel]

Nothing you can do to smoothly change the movement speed in blueprint if you are going to use CMC.

well maybe work if you tick "Server Allow Client Authorative Position"

But honestly, I would just bite the bullet and use CMC as intended.

[blazing bear]

yeah I think c++ is necessary, if you use bp only then I think GMCv2 could be worth it idk

[wanton bear]

coop game though? server authority isnt really necessary, just want whats represented to other clients to be as accurate as can be

[quasi tide]

Even in coop game, yes

More for the rubberbanding issue than the authority issue

[dark parcel]

One of the important bit is to toggle the bit value in FSavedMove, this should be what dictates the movement state and the movement speed.
Doing it in blueprint is just fighting the system imo and I don't think there's a way to toggle the bit flag in blueprint.

any other attempt will just result in rubber band / de-sync

[wanton bear]

yeah the youtube playlist basically says my use case is just about okay for janky blueprint solutions but i'm going through it anyway. probably a good entry point for learning c++

only know python and hlsl 😅

[upbeat basin]

Is the recommended/modern way of network profiling still the Network Profiler under the engine binaries?

[thin stratus]

Unreal Insights

[crisp shard]

while testing in standalone, i sprint with one character and it drains the stamina of both characters and even changes the camera of the other client. this has never happened before and i don't know what could be cuasing it

LogScript: Warning: FLatentActionManager::ProcessLatentActions: CallbackTarget is None.

this is a message i get in the server logs when sprinting and then it will sprint for both clients for some reason as if im inputing on both characters at the same time , and it doesn't alwasy do it

im almost guessing it's thinking im controlling both somehow? i have both windows up at the same time while doing it but im only inputing on one screen at a time so idk if that could be the reason but it's the left shift key

i also added an "is locally controlled check" on the entire sprint function and it still does it on both clients