#multiplayer

1 messages · Page 25 of 1

thin stratus
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But I can't recall if that actually had a proper implementation

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So it could be that as far as the live session on the backend is concerned, the Player left.

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But joining a Session also sets up a local entry in the Sessions Array for the Client, and if they don't leave/remove that, they can't join another one or create one, as that block it iirc.

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Hope that somewhat helps

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Been a while since I fought with that stuff

upbeat basin
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Does this mean every server have a session? Even without using create session?

thin stratus
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@chrome bay Is there a function or so that one can override to handle uniquely identifying the entries with FA?
I'm trying to understand how I would handle a predictively added entry

thin stratus
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Sessions are totally optional. They are only used to provide information about the Server

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Or the Player fwiw

upbeat basin
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If I join a server with a session, does it register me to it's session as well then?

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I don't think I understand what you meant with the message I replied to

thin stratus
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void AGameSession::RegisterPlayer(APlayerController* NewPlayer, const FUniqueNetIdRepl& UniqueId, bool bWasFromInvite)
{
    if (NewPlayer != NULL)
    {
        // Set the player's ID.
        check(NewPlayer->PlayerState);
        NewPlayer->PlayerState->SetPlayerId(GetNextPlayerID());
        NewPlayer->PlayerState->SetUniqueId(UniqueId);
        NewPlayer->PlayerState->RegisterPlayerWithSession(bWasFromInvite);
    }
}
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void APlayerState::RegisterPlayerWithSession(bool bWasFromInvite)
{
    if (GetNetMode() != NM_Standalone)
    {
        if (GetUniqueId().IsValid()) // May not be valid if this is was created via DebugCreatePlayer
        {
            // Register the player as part of the session
            const APlayerState* PlayerState = GetDefault<APlayerState>();
            UOnlineEngineInterface::Get()->RegisterPlayer(GetWorld(), PlayerState->SessionName, GetUniqueId(), bWasFromInvite);
        }
    }
}
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@marble gazelle Did you ever do anything with FastArraySerializer where the Client could predictively add to the Array?

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Not sure I really understand how I can handle this. I only find bits and pieces with "predict" in them in the Source Code.

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Because I end up with two elements atm on the Client

marble gazelle
thin stratus
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Hmpf

split siren
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@thin stratus Thanks for explaining the joining/leaving server sessions, I will call Destroy session on client to make sure the client can re-join other servers

marble gazelle
# thin stratus Hmpf

I'm sorry^^ But with some constraints, like not replicating UObject references, custom replication code can be very simple, if you just use NetSerialize and not delta

thin stratus
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Still wrapping my Array into a custom Struct then I guess

marble gazelle
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yes or the place where you have the array needs to impl custom replication

chrome bay
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yeah when it comes to predictively adding elements you add it, tell the server you added it, then server either sends back a "failed" RPC where client removes it (using the ID to ref it) - or you get a replication update and the client can see whether it's been accepted. GAS does that basically

thin stratus
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Yeah but the Adding is handled in two totally different scopes

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It's a cooldown that is committed via GAS Abilities

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No chance I'm gonna inject another set of RPCs to confirm stuff

chrome bay
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Ah rgr, I thought this was a bespoke system

thin stratus
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No, it replaces GAS GE Cooldowns

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I need to add the Cooldown locally, predicted, so the Client doesn't try to activate the ability a gazillion times before the Cooldown replicates.

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Also for instant feedback reasons of course

thin stratus
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Like, I assume I would need to "simply" say "This is the added element, find it via the Tag and update the Replicated properties" and then similar for updating and removing

marble gazelle
# thin stratus Any Resources on "Custom Replication", because that in itself is a bit of a gene...

Well implementing NetSerialize / NetDeltaserialize ^^
For detla serialize I know its called basically each frame to check if smth has changed, for the other I'm not sure if / how it detects if smth has changed, maybe it's also the task of NetSerialize to check if smth has changed.

So keeping the "when is the function called aside"
What you need to do is basically (for NetSerialize)
Grab the array -> write it into the NetWriter
On the client deserialize it (You usually send the number of elements and then the elements)
and then on the client you can do what ever merge logic you want.

thin stratus
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I assume I can use something like SafeNetSerializeTArray_WithNetSerialize to serialize the Array and also allow it to serialize the Entry itself?

marble gazelle
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(as this is also used for the initial bunch, you always need to send everything in NetSerialize. this is bandwidth heavy, but less CPU heavy than NetDeltaSerialze, this has better bandwidth as it can just send, what is needed, but you need to cache the last replicated states for each connected peer, but thats wrapped with the API, a lot of shared ptr stuff^^)

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never used that, so no clue what it is doing

thin stratus
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template<int32 MaxNum, typename T, typename A>
bool SafeNetSerializeTArray_WithNetSerialize(FArchive& Ar, TArray<T, A>& Array, class UPackageMap* PackageMap)
{
    bool bOutSuccess = true;
    int32 ArrayNum = SafeNetSerializeTArray_HeaderOnly<MaxNum, T, A>(Ar, Array, bOutSuccess);

    // Serialize each element in the array with the << operator
    for (int32 idx=0; idx < ArrayNum && Ar.IsError() == false; ++idx)
    {
        Array[idx].NetSerialize(Ar, PackageMap, bOutSuccess);
    }

    // Return
    bOutSuccess &= !Ar.IsError();
    return bOutSuccess;
}
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Does need a fixed MaxNum I guess

marble gazelle
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do your elements impl NetSerialize?

thin stratus
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There is a version without. not sure yet if I need to

# 
template<int32 MaxNum, typename T, typename A>
bool SafeNetSerializeTArray_Default(FArchive& Ar, TArray<T, A>& Array)
{
    bool bOutSuccess = true;
    int32 ArrayNum = SafeNetSerializeTArray_HeaderOnly<MaxNum, T, A>(Ar, Array, bOutSuccess);

    // Serialize each element in the array with the << operator
    for (int32 idx=0; idx < ArrayNum && Ar.IsError() == false; ++idx)
    {
        Ar << Array[idx];
    }

    // Return
    bOutSuccess &= !Ar.IsError();
    return bOutSuccess;
}
marble gazelle
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do you impl the << operator?

thin stratus
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No

marble gazelle
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hm test compile it, but IIRC this is not default created, usually you would use a call to some code to use reflection to read/write the data

thin stratus
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Here is the comment on it

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/**

  • ===================== Safe TArray Serialization =====================
  • These are helper methods intended to make serializing TArrays safer in custom
  • ::NetSerialize functions. These enforce max limits on array size, so that a malformed
  • packet is not able to allocate an arbitrary amount of memory (E.g., a hacker serilizes
  • a packet where a TArray size is of size MAX_int32, causing gigs of memory to be allocated for
  • the TArray).
  • These should only need to be used when you are overriding ::NetSerialize on a UStruct via struct traits.
  • When using default replication, TArray properties already have this built in security.
  • SafeNetSerializeTArray_Default - calls << operator to serialize the items in the array.
  • SafeNetSerializeTArray_WithNetSerialize - calls NetSerialize to serialize the items in the array.
  • When saving, bOutSuccess will be set to false if the passed in array size exceeds to MaxNum template parameter.
  • Example:
  • FMyStruct {
  •    TArray<float>                        MyFloats;        // We want to call << to serialize floats

  •    TArray<FVector_NetQuantizeNormal>    MyVectors;        // We want to call NetSeriailze on these *        

  •    bool NetSerialize(FArchive& Ar, class UPackageMap* Map, bool& bOutSuccess)

  •    {

  •        // Don't do this:

  •        Ar << MyFloats;

  •        Ar << MyVectors;

  •        // Do this instead:

  •        SafeNetSerializeTArray_Default<31>(Ar, MyFloats);

  •        SafeNetSerializeTArray_WithNetSerialize<31>(Ar, MyVectors, Map);

  •    }
  • }

*/

marble gazelle
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hm yeah, operator<< isn't default created for my knowledge, so either way you need to impl smth

thin stratus
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So if I were to use this, I would use some temporary TArray when reading, and then modify the actual TArray of the CooldownEntry in whatever way I need?

marble gazelle
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On the server you serialize its array,
on the client you can read the entries from the Reader entry by entry, so you don't need to allocate an extra array for it

thin stratus
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bool NetSerialize(FArchive& Ar, class UPackageMap* Map, bool& bOutSuccess)
{
  if (Ar.IsSaving())
  {
    SafeNetSerializeTArray_Default<31>(Ar, Cooldowns);
  }
  else
  {
    TArray<FAbilityCooldown> LocalCooldowns;
    SafeNetSerializeTArray_Default<31>(Ar, LocalCooldowns);
    // Do custom merging with Cooldowns property
  }
}
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Something like that?

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Or can I additional check if the Client is calling this?

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Sorry, my usage of NetSerialize usually ends at the very basics of it

marble gazelle
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yeah
technically you can do an is client preprocessor cmd or a runtime check, but Ar save/load is enough

thin stratus
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How does this behave if I were to ever send a ServerRPC with that property?

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That should use NetSerialize too or?

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But I guess the actual Array Property is then empty in that case

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On the receiving end

marble gazelle
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RPC is not using NetSerialize

thin stratus
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Ah

marble gazelle
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net serialize is for replicating state, RPC is well, RPC^^

thin stratus
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But one can optimize Structs for RPCs too or not?

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I mean, the CMC for example sends optimized vectors to the Server via FVector_NetQuantize

marble gazelle
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yes, if you send a struct via RPC it calls the same function, if the struct impls NetSerialize

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Now I get what you meant^^

thin stratus
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Sorry, I meant if I do

void ASomeActor::SomeRPC(FSomeNetSerializedStruct Struct)

marble gazelle
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yeah then the array will just be empty, as the target struct will be an default instance

thin stratus
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Okay cool

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I will see how far I get with this

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Shelved the FastArray changes for now

chrome bay
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RPC will use NetSerialize for a USTRUCT() if you have it defined

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Not NetDeltaSerialize ofc

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You can try it by sending an FHitResult through an RPC and breaking in NetSerialize()

thin stratus
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Yeah my idea now was to wrap my Array in a Struct, bascially how Fast Array does it already, but not use Fast Array but just NetSerialize for that Struct and handling the small custom rules I need myself

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WithNetSharedSerialization = false, // struct has a NetSerialize function that does not require the package map to serialize its state.

Just for learning: What does that mean?

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Cause I see FVector_NetQuantize also set that to true

marble gazelle
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this looks new to me xD

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but I'd assume it's if you don't need to replicate UObject*

thin stratus
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It's sadly worded in a way that whoever knows perfectly what's going on has all info, and everyone else reads cryptic

marble gazelle
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as the package map is used to resolve the pointers

thin stratus
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Alright

chrome bay
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yeah WithNetSharedSerialization means no UObject and no FName's within

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But it also only actually seems to be used by the shared serialization path in rep graph

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I think a long time ago there was a net-GUID ack system for FName's too. I remember talking about it with someone @ The Coalition, but there was no trace of it in engine source that I could see

thin stratus
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Man, just reading net GUID ack makes me shiver

chrome bay
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😄

thin stratus
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I can't recall what it was, but I had to deal with Actors just being invisible on Clients

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Totally randomly AIs weren't showing

chrome bay
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Basically same approach they use for uobjects but also for strings, so you can identify an FName over the network with a single GUID and not have to send the full string each time

thin stratus
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Took me quite a long time to figure that out on The Ascent. Sadly not sure what that was again

chrome bay
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Would probably be great for socket names and stuff

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Or maybe it's for package names actually..

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who knows 😄

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unreal go brrrr

thin stratus
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I think it started somewhat here

winged badger
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yeah, thanks

thin stratus
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That should help iirc

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Did not think I would ever post about that again, and funnily enough I remembered it a few minutes ago when writing with James

winged badger
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we swapped out a lot of hard refs recently and this started happening on level transition

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never on 1st seamless travel, but afterwards

thin stratus
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Are you on UE5?

# 
static int32 GNetResetAckStatePostSeamlessTravel = 0;
static FAutoConsoleVariableRef CVarNetResetAckStatePostSeamlessTravel(
    TEXT("net.ResetAckStatePostSeamlessTravel"),
    GNetResetAckStatePostSeamlessTravel,
    TEXT("If 1, the server will reset the ack state of the package map after seamless travel. Increases bandwidth usage, but may resolve some issues with GUIDs not being available on clients after seamlessly traveling."),
    ECVF_Default);
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There is apparently a console var by now

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:D

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They also seem to have taken my sort of solution as the fix

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yolo

winged badger
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no, 4.27

thin stratus
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I guess you can cherry pick the fix then and see if it helps

winged badger
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i can just add it to the engine easily enough

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i don't even have to change the precompiled engine for non programmers since this doesn't matter in editor

thin stratus
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Fair

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Wishing you good luck. I hated that bug

winged badger
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thanks, this saved quite a bit of time

thin stratus
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@marble gazelle Thanks for the hints, seems to have fixed it for now with the NetSerialize solution.

marble gazelle
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Awesome, any time^^

split siren
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I am still trying to wrap my head round the join/leave flow in UE.
I have a dedicated server which is intended to be joined purely via IP:port. Thus I assume I don't need to do SessionInst->CreateSession.
But when the player is joining the server (via IP:port), it's the AGameSession::ApproveLogin that is determining if the player is allowed to join or not.

Am I correct to assume that Creating session is mainly to advertise online in "browser" style (like old school counter strike). But if joining directly, I don't need that.

Thus leaving the game by opening local map is a correct way to leave?

I found your forum post about a blog post you created about joining/creating/deleting sessions, but that one is sadly down. https://forums.unrealengine.com/t/blog-c-session-create-find-join-destroy/36931

dim trail
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if i set a timer by a server event does that timer tick on the server?

ancient moth
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Only appear on the client

thin stratus
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Sessions are just data containers in the cloud

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They provide information of available servers to the ones asking for them

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That is indeed the exact same as a CounterStrike server list

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If you use steam you usually won't be able to connect via ip

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But only via steamid

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Steam usually hides the IP in whatever way possible

split siren
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Perfect, thanks for confirming that. I was initially confused that Session != AGameSession.
No steam here, I am using Gamelift and have backend handled in AWS Lambdas.

stoic ore
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if I call UEngine::Browse from a client while connected to a server. Will this disconnect the client from the server and travel then to the map?

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nvm I think Clients will disconnect from current server. this means exactly that.

rose egret
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how many rootmotioned AI controlled ACharacter I can handle in mutiplayer ?
forget about rendering, ... im woried about replication and badwidth limits.
those characters are zombie btw

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🤔

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default movement replication is heavy and root motion I guess it adds lots of overhead

dapper obsidian
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Any idea why GameLift doesn't update the number of connected player sessions on a game session when I join it?

unknown.png
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Oh, you have to specify the Game Session ID as part of the CreatePlayerSessionRequest.

rose egret
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how do I show notification error in editor ? message / error that popups in bottom right

kindred widget
tight crow
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Does anyone know how to stop the client from spawning before the server?
My pc is slower than my partners, and when we test with me being host, he spawns prior to me, and technically doesn't exist?

regal geyser
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In UE 5.0 when using seamless travel, there's an issue with** client loading the map faster than server**, resulting in broken state, where server doesn't know the client is already connected, breaking the game.

I've heard that this issue was already seen in 4.XX version, then fixed in later ones and it once again **resurfaced **in 5.0. My latest info is that it SHOULD be **fixed **in unreleased 5.1, could anybody please confirm it?

Or does anyone have fix on this issue? I know about this forum post: https://forums.unrealengine.com/t/ue5-seamless-travel-bug-found-we-found-the-cause-and-also-have-a-workaround/583652/16 . But someone pointed out, that this workaround causes side effects, which once again aren't confirmed, confusing me once more..

Unreal Engine Forums
UE5 Seamless travel bug found. We found the cause, and also have a ...

I think I ran into this problem too, when I host the game in my PC everyone travels to the map, when I host the game on my brother’s PC the same, but when I host the game on my less powered notebook I and my brother keep stuck in the loading. So my question is, if the bug has been reported in Jun 16, why its still happening now in Sep 21? Edit...

desert knot
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I am currently in the midst of implementing deterministic physics over the network in our racing game, which requires the state of the physics engine on both the client and server to match exactly for every simulated frame. I am running into an issue where the client and server get out of sync, where either the client or server runs slightly slower even though I am using the same timestep on both. In these cases I start to miss out on input from the slower side and I'm not sure the best way to solve this. I can delay simulating on the server for a tick when the clients are slower for example, but this results in jumpy behavior and overall seems like a poor solution. Is there a common way to deal with this sort of situation that I'm not thinking of?

dark edge
desert knot
# dark edge You got an input buffer?

Yes, each vehicle has an input buffer. I believe the issue is that since the client and server aren't in sync, the client isn't capturing input as fast as it is being processed

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Or on the other hand, the opposite problem, it's being captured faster than it can be processed. I've seen both happen intermittently

loud elk
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Is there a risk in enabling "Allow Client Side Navigation", so that the SimpleMoveToLocation functions in multiplayer? Is this opening myself up to potential cheating since the path is calculated on the client vs the server?

dark edge
desert knot
dark edge
desert knot
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That part is already implemented but missing out on input is causing issues. Most of the implementation is based on how Rocket League does it, so I know it's possible, I just think I'm missing something

dark edge
desert knot
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No, I am doing client-side prediction

dark edge
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So you got rollback?

desert knot
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Yes

dark edge
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gotcha. Yeah I didn't go down that route because I'm doing player-made vehicles. It's bad enough already, implementing rollback for little jimmy's dividebyzeromobile with 12 wheels and 6 engines just feels like a bad time

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But we're not racing, so I just live with the ping delay and everyone sees approximately what happens on server.

desert knot
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Totally understand that.

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That would be quite a headache, even a relatively simple vehicle has a ton of variables to think about

dark edge
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I really only replicate the control state and the chassis movement. Everything else is local

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so you and me don't necessarilly agree on how much the suspension compressed on that landing, or what RPM the engine is at this second, but we do agree on what gear I'm in and my throttle and the overall motion of my vehicle

desert knot
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Only slightly jealous. Our system has me tearing my hair out for the last few weeks. Unfortunately it's a very fast-paced game with very non-standard physics so we basically have to do it this way

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But I feel like I'm rounding a corner on it, hopefully I can figure out the rest of these lingering issues

pallid mesa
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deterministic physics ough >_< shaky-shaky

young spoke
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is there something special with port 7777?

The engine is continuously creating a GameNetDriver for it even though I don't have that port specified anywhere in my configurations.

LogNet: Created socket for bind address: 0.0.0.0:7777 LogNet: GameNetDriver IpNetDriver_22 IpNetDriver listening on port 7777

sinful tree
young spoke
halcyon totem
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I think I fixed my issue but now I am getting this error

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SetReplicates called on non-initialized actor

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Directly setting bReplicates is the correct procedure for pre-init actors.

olive kraken
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Hello!
Has anyone had an issue with AI rotation not replicating properly on client-side when using root motion? i.e AI character using a combo while rotates, client sees a straight root motion, and when the montage ends, teleports to the real server final location including the rotation over time.
There are certain conditions need to be met, otherwise won't happen at all:
-Allow rotation using root motion has to be on.
-Usually happens on top of hierarchical instanced meshes, or spawned meshes that were not part of the persistent level at initialization.
-Network might be need to be saturated.

Worth to mention, it is not happening 90% of time, it feels like happening over time, which makes it harder to isolate the issue. I'm also using GAS, thou shoudn't be relevant since AI is always server initiated. I'm also prioritizing net updates on AI to be completely sure positions of AI are refreshed, is there a chance that the rotation + root bypass the network priority?

Any pointers or clues will be much appreciated, thanks!

manic trellis
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I cannot access to the Website

thin stratus
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Yeah I know. The MySQL setup of my WordPress page is shite

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Will restart it once I'm up

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Thanks for reminding me

frozen horizon
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C++ | replication
yo,
I'm having an issue with OnRep, wondering if anyone knows the answer. The issue is that the repnotify seems to call before the actor has even spawned in? So the OnRep event will call, but the debug log will show a null actor, the actor is a blueprint actor if that has any effect. Im just wondering if this is solvable.

civic belfry
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has anyone messed with Iris replication in 5.1? Seems like the plugin's enabled by default but not sure if it's really doing anything yet

manic trellis
thin stratus
thin stratus
manic trellis
frozen horizon
thin stratus
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It's fine, but they usually replicate in two steps if the Actor doesn't exist yet.

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Since a Pointer is just a NetGUID

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You basically are getting an OnRep for the NetGUID which can't be resolved. Once the Actor is valid it should call again though.

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Simply ensure the Pointer is valid before accessing it

frozen horizon
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it works about 75% of the time, but my log says that 25% of the time it just doesn't call, which is strange

worn wagon
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I've been struggling to decide the best way to do automatic gunfire. The two main choices would be sending each individual gun shot, which is much easier to keep in sync but can result in somewhat choppy firing because of variable latency. The other being sending a startfire/endfire rpc which would be perfectly smooth, however variable latency also means they could fire less/more than the server and they become out of sync. This would only be a problem for higher firerate weapons but that's enough of a reason to make me wary of it. Of course I could just correct the ammo on the client after they stop firing but that's not ideal.

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Am I correct in my thinking?

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Client starts firing with a ping of 150ms, then stops firing at 100ms (extreme example but still, with a firerate that shoots faster than 20 shots per second it will be out of sync)

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I'm not sure if it's even worth worrying about this edge case as it's so extreme

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I have a mac 10 which is the higher end of firerate of weapons in my game and that's 18 rounds per second

frozen horizon
thin stratus
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You can always send Timestamps and what not

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To get an idea of how long the client actually shot for

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And do some padding here and there

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Fwiw, if the client stops firing the weapon, then that's what should, if possible, be the truth

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Feels a lot better that way

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You can set up some net sync clock to get some RTT and Latency data to play around with

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Or use the ExactPing from the PlayerState I guess

worn wagon
thin stratus
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(although I think that is calculated with frames in mind)

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For spray and such you can use a RandomStream that you reset when stopping/starting the shot

worn wagon
thin stratus
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Server should have auth

worn wagon
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Even if I add that though, client still has auth on hitreg otherwise I need to implement rollback. This is a party game played on listen servers with your friends btw

tame sapphire
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Multiplayer turnbased problem I'm wondering if anyone can help with?
Ive been converting movement into an actual button that spawns an actor via class but the actor is not spawning when I SR_SET_Movement on the button click, Im just wondering if the widget button should set a temp var on the PlayerController?)
https://media.discordapp.net/attachments/974031882599686194/1033331195796275270/unknown.png
pretty sure this is the problem...
and i know im not passing anything directly in here to SR_Set_Movement its just that in the button i thought i could set it with
https://media.discordapp.net/attachments/974031882599686194/1033331508871712768/unknown.png?width=1058&height=376
the button works as intended other than spawning an actor which is where i was going to move the movement logic into or should i be using the player state here to pass on the player controller and setting it in the player state from the button?
If it helps this is the spawning section in the player controller
https://cdn.discordapp.com/attachments/974031882599686194/1033334161546674256/unknown.png

thin stratus
#

But here is an example of what I mean:

We use GAS for our Abilities but we had issues with Cooldown, as Cooldown was fully predicted on the Client. But if the Activation of the Ability took 1 sec the first time and the next time 0.5 sec, the Server might still be on cooldown. (extreme numbers to make it more obvious).

So we changed it to Server Auth Cooldown with only predicting the Adding (so the client locally instantly is on cooldown). Removing was Server Auth.
To counter the RTT, so sending the ActivateAbility RPC and receiving the Data of the CD being over from the Server, we simply reduce the Duration of hte Cooldown on the Server by RTT.

Just an example of going a bit out of your way to make it feel correct on the client. @worn wagon

worn wagon
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Using the synced server time variable?

thin stratus
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Component on the PlayerController

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That every now and then sends an RPC back and forth

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With the Timestamps to calc how long it took

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It's a byproduct of syncing ServerTimeSeconds

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The default ones from GameState are garbage

worn wagon
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Yeah I think you may have been the one who told me this before haha

thin stratus
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Can also be @pallid mesa who wrote some docs about it. I did it similar , cause the concept is the same after all

worn wagon
thin stratus
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Something along those lines yes

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Check pinned messages

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From Vori

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Last link in their pin

worn wagon
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Oh man there's a lot of good stuff on pinned

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Thanks a lot, should be an interesting read 🙂

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I swear making the same singleplayer game in multiplayer increased development time by at least 4x

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I can only imagine how difficult it would be without an engine that already has a lot of the groundwork covered

pallid mesa
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aye, feel free to ask whatev, it's a post that got semi-written in here compiling knowledge from many fellas 😄

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so huge shotout to em all

twilit radish
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I hate dedicated servers already

unknown.png
twilit radish
pallid mesa
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sure

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:'D

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now im fullon with mass

twilit radish
#

I'm attempting to run the third person template on my raspberry pi as a dedicated server x)

pallid mesa
#

nice :D

twilit radish
#

The first step towards world domination >:D

kindred widget
#

Can I mark actors on the level to replicate after they're loaded? Since they're spawned with the level locally, will this even work?

thin stratus
#

Could work, since I think they are stably named

solar swallow
#

I'm trying to add UI for each player through the player controller. The issue is when I try and print the controlled pawn, it prints out the same pawn. This leads me to believe only 1 player controller is active even though I have 2 clients + the server

unknown.png
#

But when I add UI through the player controller, it's visible on all clients, but it doesn't work. For example, the UI has a reference to the player it belongs to and whenever it needs to access that player, the game crashes because the reference is null. The reference gets set through the player controller. It works on the server, but not for any clients

solar swallow
#

wait nvm, I was being dumb

harsh ice
#

After any damage and health getting 0 players is not destroying in both clients

worn wagon
solar swallow
#

👀

fathom aspen
#

This is amazing, thanks for sharing!

twilit radish
#

I clicked on the WoW video and this is almost how it immediately starts off.

unknown.png
#

🤣

#

Also I completely forgot that repository existed, I even had it starred D:

harsh ice
#

Can anyone help me ?

twilit radish
#

With what?

harsh ice
#

Destroy player in multiplayer

twilit radish
#

Your player is likely replicated so you just need to destroy it on the server and the engine takes care of the rest.

fathom aspen
harsh ice
#

I did but it's not working

twilit radish
#

Can you show your player setup and how you destroy it? Also have you made sure by debugging or printing messages that your code actually gets executed?

harsh ice
#

Yes it destroys weapons but not characters.

kindred widget
#

Any ideas why a server initiated multicast will run on both a server and client. Yet the server adding a variable to a replicated array does not trigger an onrep on client?

twilit radish
#

That's the way multicasts work. They run everywhere as long as that actor is relevant.

kindred widget
#

Yeah, that was half of the point.

twilit radish
#

Do you actually update the array or do you update an element inside of the array? I believe the latter was a bit problematic if I recall correctly.

kindred widget
#

Straight up add. Has to be changing the array. Definitely ran on server.

#

Is a TArray of uint16. Uproperty, marked ReplicatedUsing

#

Has a DOREPLIFETIME

#

In a component, not sure if that's relevant. Both the multicast and the replicated array are.

fathom aspen
#

The component is replicated too ofc right?

kindred widget
#

The multicast works. Was why I started with that. 😄

fathom aspen
#

Right, right was double checking 😄

kindred widget
#

Sec. I didn't think to see if the value is actually arriving. Was assuming the OnRep would run without incident.

quiet fjord
#

guys how to improve the optimization for the lag for the replication of the animations

twilit radish
fathom aspen
#

Guess

#

Which also shouldn't be an RPC at all, but sadly that what happens when the net compendium is overlooked 😔

solar swallow
#

I'm still learning but multicast shouldn't be called for destroying an actor right? Cause any late joiners and irrelevant players that become relevant will still see the destroyed actor right?

fathom aspen
#

Correct. Though it could have been destroyed for them if the multicast RPC was to execute on server, still not a good practice and error prone.

#

Replicated actors are ofc not destroyed by a multicast RPC

kindred widget
#

Hmm. Nope. No replication at all. :/

fathom aspen
#

You are calling the OnRep explicitly after the addition right?

#

That's why it's firing on server?

kindred widget
#

At the moment for testing, yes.

fathom aspen
#

Could it be that the client for some reason thinks that the local value isn't any different from the server's and thus not firing the OnRep

#

Have you tested with REPNOTIFY_Always?

kindred widget
#

Won't make a difference. I just tested the array client side on tick. It's not getting any replication at all.

twilit radish
#

It's incredible how difficult it's to figure out how to do this while it's the most easy thing ever.

#

"Download cool compiler thingy, regenerate source build files, compile and it magically works"

twin juniper
#

That's all i have (of course it does not have an OnRep, but it had one before without any issue)

kindred widget
#

It's not the array. I'm trying to replicate a simple array of instances that should be scaled to zero for a HISM component. The issue stems that I'm using the foliage components, which I cannot override the actor for. So a world subsystem is setting them to replicated and always relevant both on actor and client. The component being used I can actually subclass, so I was doing the networking there with the array. The component can RPC a multicast, but cannot seem to replicate this array.

#

Client just prints a length of zero. Server's shows correctly.

#

Uhh..Okay. That's a new one. O.o I can turn off replication in the component, and the RPC still works.

#

Well.. that explains why my replication isn't working, but what the fuck? 😂 Why can you RPC through a component that isn't even replicated?

fathom aspen
#

Lol. Have a feeling that replication is broken for HISMComps

kindred widget
#

Yeah.. I was really kind of hoping not to need a huge container elsewhere.

solar swallow
#

What is a good way to approach updating UI? Currently, I'm calling a server RPC which will run some logic. And then from that server RPC, I call a client RPC which will set some variables in the widget and call the update function on it. The problem is the client RPC function gets called with authority and the widget UI reference only exists on the client. I've tried setting the widget reference to replicate but that doesn't fix it.

twilit radish
#

Widgets aren't capable of dealing with network things. The general flow is that the server updates something in for example the game state, player state, player controller or whatever and that when arriving on the client it gets passed on to your UI locally 🙂

twin juniper
#

that might be why

solar swallow
twilit radish
kindred widget
#

@solar swallow One thing to take into consideration for UI is that you have to follow the basic core concept. UI is for displaying the state of gameplay objects and allowing input into gameplay objects and that is all. UI should never have state of the game and should only contain state related to their own display. If you cannot remove all UI from the screen and then put it all back then your UI isn't set up correctly. And all of this is before any networking considerations. Gameplay should never know that UI exists. UI should be able to bind delegate or tick to update itself and gameplay classes should simply be able to go about their day setting new state and broadcasting delgates. If anything cares it should be bound to that delegate to do what it needs.

Nothing changes in this as far as networking goes except that you also need to broadcast those delegates where they matter in OnReps.

twilit radish
solar swallow
#

Thanks for the info

#

Is it fine if the UI has a reference to the player so it can get health/stam/ etc values

harsh ice
#

How can I implement fpp death animation

#

There is no fpp death animation.

young spoke
#

i have a weird issue that only started happening when i updated to ue5...

I have a level called MainMenu, a MainMenuGameModeBase and a MainMenuPlayerController. I run game in standalone, and my MainMenuPlayerController calls ClientTravel like this:

ClientTravel(TEXT("127.0.0.1//Game/Maps/ClientGame1"), ETravelType::TRAVEL_Absolute, false));

which used to connect the player to a waiting dedicated server playing ClientGame1

now i get LogNet: Warning: Travel Failure: [ClientTravelFailure]: Invalid URL: /Game/Maps/MainMenu and nothing happens.

I don't understand why it's trying to travel to /Game/Maps/MainMenu when the URL is for ClientGame1

timid moat
#

Hi!

#

I've just started to learn Unreal and I want to learn how to develop multiplayer games.

#

Do you know a book or something to start with? I want to know how multiplayer works in Unreal: about servers and clients, etc.

#

Thanks a lot!

young spoke
timid moat
solar swallow
#

this video helped me a lot

#

gives examples in bp and c++ as well as a proper explenation

timid moat
timid moat
pale obsidian
# timid moat Do you know a book or something to start with? I want to know how multiplayer wo...

Alex Forsythe also has a good video: https://www.youtube.com/watch?v=JOJP0CvpB8w

YouTube
Alex Forsythe
Multiplayer in Unreal Engine: How to Understand Network Replication

An overview of the essential concepts for writing multiplayer game code in Unreal, in under 25
minutes or your money back.

Sample project: https://github.com/awforsythe/Repsi/
Patreon: https://patreon.com/alexforsythe
Twitter: https://twitter.com/alexforsythe

00:00 - Introduction
01:24 - Net Mode
03:33 - Replication System Basics
05:13 - Acto...

▶ Play video
#

and a soothing narration haha

timid moat
fathom aspen
timid moat
fathom aspen
#

What you was suggested are the starter pack. Remember to look at the other resources while you climb your way up 🙂

twilit radish
#

I'm sad, my Raspberry PI OS is 32 bit which Unreal doesn't like supposedly with the ARM architecture so now I need to upgrade it xD

real ridge
#

guys do you know how I can show ping

#

in game i mean i am connected to dedicated server

#

and i want know ping there

kindred widget
#

Playerstate stores a compressed ping per player if memory serves.

real ridge
#

i wanna see ping in log like when you play csgo, i will see in client widget FPS, ping and packet loss

young spoke
#

anyone know why in ue5, ClientTravel(TEXT("127.0.0.1//Game/Maps/ClientGame1"), ETravelType::TRAVEL_Absolute, false));

ends up calling

Browse(...FURL="MainMenu?**closed**"...)

twilit radish
#

Because your URL isn't valid. It needs to look like 127.0.0.1?map=Game/Maps/ClientGame1 and from there on you can request that parameter on the server.

#

Although I'm not 100% sure if slashes work like that as argument, but you get the idea.

#

Only took two hours to compile the server and install a 64bit OS on the server lol.

kindred widget
#

Thom going places. 😄

twilit radish
#

Exactly! Going bankrupt.

sinful tree
#

Maximum player count: 0.5 (yes, half of one player)
(I kid, I kid)

twilit radish
#

To be fair it has 4 cores running at 1.6GHz, no it's not going to run Fortnite but it can definitely run a few players.

sinful tree
#

Yea

real ridge
#

guuuys please can you give me tip how to show ping when I am joined to session ?

twilit radish
young spoke
#

for the love of god, is there a link that describes FURL params clearly

#

this used to work in ue4

real ridge
twilit radish
#

Because they divide it by 4.

/** Replicated compressed ping for this player (holds ping in msec divided by 4) */

#

So you need to multiply it by 4 to get the proper result again.

#

Although to be fair you can also call GetPingInMilliseconds() and that will do it for you.

real ridge
#

i see but i dont know what entry need get ping in ms

twilit radish
#

You need to grab it from the player state. Which you can for example get from the player controller.

real ridge
#

nope nothing from player state is fitting there

#

i tried

twilit radish
#

What engine version are you using?

kindred widget
#

GetPingInMilliseconds is a function on the playerstate. Don't call GetPinginMs. Call GetPingInMilliseconds.

twilit radish
#

Oh I didn't even realise lol.

real ridge
twilit radish
#

Then what Authaer said 🙂

real ridge
#

i will try

#

thx guys

loud elk
#

I think I'm misunderstanding something fundamental about replication...
My goal is that when I click on the ground, to make a RPC to the server passing the hit location, which uses UNavigationSystemV1::FindPathToLocationSynchronously to generate a NavigationPath. I then set that NavigationPath to a property named NavPath and have an OnRep_NavPath defined which attempts to use the navigation path. However my NavPath is always null on the client, even after OnRep_NavPath fires.
What am I doing something wrong? This is all within an ActorComponent that is set to replicate if that matters.

capture.png capture2.png
tidal veldt
#

What is the correct way to replicate the removal of an instance of an instancedmesh in the foliagesystem?

olive kraken
#

Hello! I recorded a video showcasing our rotation replication problem, in case clicks about the potential issue.
As I mentioned before, it not always happens (which makes it hard to reproduce), but it happens sometimes on top of different procedurally generated HISM/ISM
Aparently, under saturated network root motion rotation is not updated properly and gets the update right after the notify ends, which translates into a teleport between the difference of the montage allowing rotation in root motion and not.
Does someone know what could be potential issues or way arounds? should I force net update on the tick notify maybe?
Thanks!

solar swallow
# loud elk I think I'm misunderstanding something fundamental about replication... My goal ...

You need to call the onrep function manually after changing the value. And I think you also need to implement GetLifetimeReplicatedProps in order for the variable to get replicated. void ASomeClass::GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const { Super::GetLifetimeReplicatedProps(OutLifetimeProps); DOREPLIFETIME(ASomeClass, ReplicatedVariable) }

loud elk
sinful tree
loud elk
#

I know that the CharacterMovementComponent is naturally validating character movement against the server, so my entire goal had been to leverage that for click-to-move by generating vectors based on current location vs a path point. If checking that checkbox is all i need to do, to make click to move work securely in multiplayer, thats great

#

I dont really understand why that would prevent a Navigation Path i set manually on a property from replicating though..

loud elk
sinful tree
#

Dang. Thought that may have helped. If that's the case, then it's probably not something that can be directly replicated - like you can't just replicate UObjects, you have to do some extra work to replicate them.

loud elk
sinful tree
#

I'm not certain with Simple Move To. One way to check is to spawn a wall only on the server (not replicated) that has some collision and see what happens when the client tries to move through it.

#

If it passes through it like it wasn't there, then it wouldn't be secure.

loud elk
#

I've dug though the C++ for quite a while and I believe NavigationPaths still use the underlying CharacterMovementComponent. Ok, good point that should be fairly simple to do i think

sinful tree
#

I honestly can't really think there would be an issue other than the client thinking it can move somewhere where it actually can't.

vivid seal
#

Hi, I've recently got predicted root motion working with Gameplay Tasks and that's all functional. Now I'm trying to figure out how to also get server-initiated motion working (like knockbacks) without jitter. I know that I need the client to "predict" that he's getting knocked back locally first before actually running it on the server, but I'm having trouble getting that not to lag. Currently my approach is to replicate the gameplay task with the root motion down to the owning client in the CMC's ReplicateSubobjects, then have the client run the gameplay task (which performs the root motion), and send a flag up using network move data that they have executed the root motion, after which the server receives the flag and runs the gameplay task. This works except the client jitters a lot. I think it has something to do with the order of RPCs that happens, which was also an issue when I was predicting (needed to FlushServerMoves before performing any predicted root motion). Any ideas?

loud elk
subtle patrol
#

Hey just a noob question, is there any possibility to add like many server instances on one dedicated server?

#

If yes, is there any doc or any information about how I can configure that

#

I read that you can actually but with different port each instance

#

Although how can I make a simple system that close let’s say an instance and open a new one at each of available ports

#

Is there any limitations?

#

That’s all ty

#

Or should I choose aws gamelift and that’s all 😁

kindred widget
#

Okay. So.. After a ton of breakpointing and tests. I am still baffled by this.

Facts:
•Actor is a part of the level. It's class does not replicate by default and server sets it to replicated shortly after starting.
•Actor is replicated.(Actor and it's component have no problem being sent over network through pointers)
•Component is replicated (Also tested this by tracing on the server and hitting it, and setting it in a replicated pointer, the client resolves a correct pointer).
•Array of integers is marked ReplicatedUsing, property is DOREPLIFETIME macroed in GetLifetimeReplicatedProps.

Issue:
A replicated Array in the component still will not replicate. Adding a new entry on the server does not trigger any form of replication. The client's array size stays zero, the OnRep never runs.

#

Uh.. Huh. After writing that out I just had a recollection of.. I think Cedric telling me that sometimes actors won't replicate if you only have one replicated property. I added an integer, replicated it. And suddenly everything I expect to happen is happening. How fucking Unreal™️

solar swallow
#

What is the best way to replicate components created at runtime. Currently, I'm creating a static mesh, spring arm, and camera component on the server. They are all set to replicate. The issue is only the Mesh is valid for the client, spring arm and camera component are both nullptr. Everything works properly on server. Mesh = NewObject<UStaticMeshComponent>(this); if(Mesh) { Mesh->RegisterComponent(); Mesh->AttachToComponent(GetRootComponent(), FAttachmentTransformRules::SnapToTargetIncludingScale); Mesh->SetStaticMesh(ShipProperties.Mesh); Mesh->SetWorldLocation(GetActorLocation()); Mesh->SetGenerateOverlapEvents(true); Mesh->SetNotifyRigidBodyCollision(true); Mesh->SetCollisionProfileName("BlockAll"); Mesh->SetIsReplicated(true); } SpringArm = NewObject<USpringArmComponent>(this); if(SpringArm) { SpringArm->RegisterComponent(); SpringArm->AttachToComponent(Mesh, FAttachmentTransformRules::SnapToTargetIncludingScale); SpringArm->SocketOffset = Mesh->GetSocketLocation("Camera") - Mesh->GetComponentLocation(); } Camera = NewObject<UCameraComponent>(this); if(Camera) { Camera->RegisterComponent(); Camera->AttachToComponent(SpringArm, FAttachmentTransformRules::SnapToTargetIncludingScale); }

clear island
#

quick question, is a mesh "collision enabled" property automatically replicated?

#

I'm talking about this one

unknown.png
#

if I change it on the server, will it automatically replicate to all clients?

solar swallow
#

I don't know if I'm doing something wrong but my client rpc is running on the server. I've declared it as a reliable client rpc with validation. I call it from the server. But when I check if I have authority or not inside the client rpc, it says I do. Anyone know why?

ember dagger
rocky night
#

Hi Guys, i use the move compenent to (node), to set the player in a right interact position.. works on server, on client to but the client cant move out of th eposition and is stucked and jitters. anyone have aidea?

timid moat
#

Hi!

#

If I want to create a multiplayer game, do I need to do something special when I create the project in Unreal?

#

Thanks

#

I think I only have to set the number of players in the Multiplayer options to more than one, and that's it.

pallid mesa
#

omg

#

u need to program your whole game to be multiplayer ready

#

and its a lot of work

fathom aspen
#

I think he was referring to any special editor settings

#

If that's the case then that's sufficient for now. As time goes on you will start emulating lag and launching standalone/packaged.

timid moat
fathom aspen
#

Yes that's exactly what vori meant

timid moat
fathom aspen
#

You aim for MP from the start

#

There is no magical button that makes your game multiplayer ready

#

Sadly this isn't the case as of now 😔

timid moat
#

So, I don't need to do anything in the editor. Just create a project. The same project will work as standalone or multiplayer.

pallid mesa
#

You dont need any specific settings. You need first to define your server model (listen or dedicated) which comes by analysing how your game will be

#

or maybe both

fathom aspen
pallid mesa
#

Unreal has settings to test your multiplayer features in engine by simulating a multiplayer connection in PIE through the two models I mentioned before

timid moat
#

In other words: What do I need to do if I want to create a Multiplayer game? The first step is create the project in Unreal. What do I need to do to create a multiplayer game project in Unreal? Thanks.

pallid mesa
#

But PIE testing isn't as trustworthy as running real connections (running each one in one process is better!)

#

So you need to learn any API that lets you create sessions with a subsystem

fathom aspen
pallid mesa
#

for example CommonUser, and steam subsystem

#

then you need to understand RPCs and replication

#

which make up for Unreal's networking model

timid moat
pallid mesa
#

Finally, once you've understood RPCs and replication you can start doing basic stuff

#

my core recommendation to learn these networking primitives is reading cedric's network compendium (pinned above)

#

you'll also learn things such as the gamemode only exists in the server

fathom aspen
#

But... but... my client needs to access the GameMode, can't I just replicate it?

pallid mesa
#

yes you can technically modify the engine to make it that way

#

kekw

#

reject tradition - embrace replicated gamemodes

fathom aspen
#

Breaks the entirety of Unreal

twilit radish
#

😮

pallid mesa
#

@timid moat i think you got enough info with all I wrote

timid moat
#

Sorry, I don't understand you. I only want to create a game ready to be a multiplayer game. I don't need to know all the steps that I have later. I only want to know what I have to do in Unreal to create a multiplayer game here:

unknown.png
pallid mesa
#

just click one of these and done

fathom aspen
#

You create it just like you create a non-multiplayer game

timid moat
#

THANKS

fathom aspen
#

If that's what is worrying you

#

Nothing special

pallid mesa
#

hehehe

fathom aspen
pallid mesa
#

okay serious debate

#

all ue samples should work in multiplayer.

twilit radish
pallid mesa
#

do u guys agree?

fathom aspen
fathom aspen
twilit radish
fathom aspen
pallid mesa
#

i dont agree

#

hahaha

fathom aspen
#

To which part lol

twilit radish
#

If we get Matrix multiplayer we’ll get a million GTA knock-offs 😂

pallid mesa
#

multiplayer code pollutes the source code in something that is meant for beginners to learn, so if someone isn't interested in multiplayer it will be a PITA

pallid mesa
#

it got some validation server side

#

and that's why its online feels as smooth as butter

fathom aspen
pallid mesa
#

ye XD

fathom aspen
#

Makes sense for them to be client auth though

pallid mesa
#

well its the tradeoff XD

twilit radish
#

We need a MMORPG template 👀

#

That works on my raspberry pi of course

twin juniper
#

since host is the "server"

#

if a cheater is the host he can bypass all those server checks i guess ?

pallid mesa
#

yes

#

although i didn't know gta was ls based

#

at least fivem and co aren't iirc

twin juniper
#

that's why gta 4 online is still up

#

they shutted down 5 online on old old gen tho because they had servers to maintains (for online stats etc)

twilit radish
#

I'm looking into the Iris replication system, it's pretty interesting actually 👀

Enable delta compression for replicated objects. Default is true.

twin juniper
#

What a day, i f*cked up all of my project and i don't know how 🙂

twilit radish
#

Source control is your best friend 😛

twin juniper
#

I have git

latent heart
#

Source control is only as good as your last push.

twin juniper
#

and from what i see i don't modified any of those files

#

corrupted in bp

latent heart
#

Are you using cpp?

twin juniper
#

since it's huge af

twin juniper
#

my BP does not detect my HeroComponent anymore (cpp comp)

unknown.png
#

i don't modified it

latent heart
#

Do you have any components in your classes marked as Editable in the UPROPERTY?

twin juniper
latent heart
#

That has the tendency to corrupt BPs.

#

Never mark components as Editable. Only Visible.

twin juniper
#

I just did a clean compile by deleting intermediate/Binaries

twin juniper
#

i don't modifed it

#

i guess it's on BlueprintType

#

wait a sec

#

nvm

#

UCLASS(Blueprintable, Meta = (BlueprintSpawnableComponent))

#

but still, i don't modified it. My BP_Pawn has the same issue, all corrupted i can't put my cpp character class as parent anymore for some unknown reasons

#

i don't modified those classes since a week

#

I even can't recreate my BP since i can't add my HeroComponent lol

latent heart
#

It doesn't need to be a BlueprintType to be Blueprintable.

#

It just means you can't use it as a type in BP (for a variable)

#

Or cast to it.

twin juniper
#

Ikr

#

that's not the issue tho, i don't touched anything to it since it's existence since it's a lyra component

latent heart
#

Didn't say it was!

twin juniper
#

there is not a single error 😐

latent heart
#

I did mention the Editable/Visible thing, which you said you do have Editable stuff. Then you said you didn't. Shrug

twin juniper
#

except when i force open the BP to say it doesnt have a parent

twin juniper
#

clean BP, where the f is my HeroComponent lmao

unknown.png
latent heart
#

Because those are common UPROPERTY specifiers!

#

😛

twin juniper
#

i already made a clean compile again

#

that's literally the last thing i modified on my project and it has nothing to do with my HeroComponent or my Characters BP

unknown.png
kindred widget
#

Err.. What do you need for FastArrays in UE5? Made one like I'm used to. Have NetSerialization.h included, and I'm getting a ton of unresolved symbols like FGuidReferences

twin juniper
#

You should not even need NetSerialization.h tbh

#

i don't have it included

modern cipher
twin juniper
#

i was searching but yeah it's that

kindred widget
#

Oh, yeah. Thanks. 😄 Just looked at the .h file for that. Docs still noted it as Engine. :/

latent heart
#

Which docs?

twilit radish
#

We have docs?

#

😛

latent heart
#

There's the API reference.

tidal veldt
#

Trying to replicate an array of structs using with ReplicatedUsing. Calling the replication function from the server, I see that both server and client call the replication function, however on the client the variable isn't updated - am I supposed to pass the updated variable in as a parameter in the OnRep_ function?

latent heart
#

No

#

When you say "isn't updated" what do you mean?

#

Is the array size wrong? Is the data in the structs missing?

tidal veldt
#

the array is empty, whereas Ive just added something to it on the server

latent heart
#

It may not be replicated right away or it may not be relevant.

#

Or the class itself may not replicate at all.

#

Which class is it?

tidal veldt
#

its a custom class. But ive set bReplicates = true and bAlwaysRelevant

#

a custom actor class

latent heart
#

A custom class based on what?

#

Actor, right.

#

Just to check, you're absolutely not trying to set the value on the client and have it update on the server?

tidal veldt
#

no the function that adds to the array is UFUNCTION(Server, Reliable )

#

but in other news it works now

#

just recompiled

#

this always happens when I ask questions on this discord

latent heart
#

Lol

twilit radish
#

😄

tidal veldt
#

XD

fathom aspen
#

I mean Daekesh is a wizard, so that could be it

tidal veldt
#

No doubt 😄

fathom aspen
tidal veldt
#

A custom actor class I made

fathom aspen
#

Is it owned by the client?

tidal veldt
#

each client has their own version of this class afaik

#

but the replication works now

#

the class itself is replicated

#

to the clients

twilit radish
#

There's only one real solution: FFastArraySerializer.

pallid mesa
#

still, be careful where you call your server rpcs! they can only be invoked by client owned actors

fathom aspen
pallid mesa
#

quack 🦆

tidal veldt
latent heart
#

If the RPC is firing, I'm assuming it is a client-owned actor.

#

Player state, pawn, controller - basically

tidal veldt
#

I tested this in game from client and from server, getting the same - wanted outcome

fathom aspen
#

GetOwner?
Looking through the logs for warnings?

pallid mesa
#

so tell us Liine, where are you calling this rpc, in which function?

#

beginplay maybe? (it got already server flow, so no need for a rpc!)

tidal veldt
#

no

twilit radish
#

I don't get why this is till going on, it works now right? Lol.

fathom aspen
#

Yes it works™️

pallid mesa
#

it is going towards a proper understanding of why the logic is working Thom

#

and that's critical to understand multiplayer

twilit radish
#

Nonono. If it works, it works ❤️

#

😂

tidal veldt
#

mouse click happens on client, PC elevates the click to server to do some checks, then calls this function to harvest some plant in game on the server which does some checks and agrees that plant should be harvested, updates an array of plants that are harvested which is then replicated to client for them to remove for the InstancedMeshcomponent that holds them

fathom aspen
#

Nothing works under my radar patrick_hehe

fathom aspen
#

The server RPC the PC did is sufficient

tidal veldt
#

ah

#

just "feels" better to be doubly sure XD

fathom aspen
#

So what was happening is that the second RPC was executing like a normal function

#

executed in the local CallSpace

tidal veldt
#

what if I want to go that code path from somewhere else in the future

#

without already being on server

fathom aspen
tidal veldt
#

suppose a check and RPC would be better then

#

so its safe if it were to be called from client

fathom aspen
#

I'm not sure I get the question. Do you want to be able to validate what the client passes through the RPC?

tidal veldt
#

No I mean in the use case I have right now I know Im only every calling the functions from server, as I know I go through the PC etc, but if I were to, in the future, have a use case where this same code path could be taken from somewhere else, maybe on the client

#

I would then need to have a check in the function to see what kind of authority I have and if its the client to a call to the server instead

#

if I am to remove these uneeded server calls I have now

fathom aspen
#

Well you can't fire server RPCs from actors that are not owned by the client.

tidal veldt
#

right

fathom aspen
tidal veldt
#

yea

solar swallow
#

What methods are there to create a component on the server and then replicate it down to the client? I've tried setting the component to replicate but the client still doesn't know it exists

#

I've tried calling a rep notify but that seems to run on the server/authority only

#

The actor thats adding the components to itself is not possessed by any client on start, I'm not sure if that has anything to do with it

fathom aspen
#

Show code to how you're doing this?

latent heart
#

Do you assign the component to a UPROPERTY that is marked as replicated?

#

Is it added to the InstancedComponents array (not sure if required)?

solar swallow
# fathom aspen Show code to how you're doing this? 
SpringArm = NewObject<USpringArmComponent>(this);
if(SpringArm)
{
  SpringArm->RegisterComponent();
  SpringArm->AttachToComponent(Mesh, FAttachmentTransformRules::SnapToTargetIncludingScale);
  SpringArm->SocketOffset = Mesh->GetSocketLocation("Camera") - Mesh->GetComponentLocation();
  Rep_SpringArm();
}```
solar swallow
solar swallow
fathom aspen
solar swallow
#

thats being called on server and then I call the rep notify

fathom aspen
#

You are replicating a pointer to the component, not the component itself

#

There's a big difference between the two

solar swallow
#

oh

kindred widget
#

Need a replicated pointer, to a replicated component, on a replicated actor.

solar swallow
#

So if I just add SpringArm->SetIsReplicated(true) before I call the rep notify, it'll replicate the component itself?

fathom aspen
#

Right

kindred widget
#

So. About the weird Replication issue where if you only have one property, it doesn't replicate. Is there any way around that without a second property? I can't seem to cause it with FastArrays which is nice. A Single normal TArray still won't replicate unless I add another replicated property though.

lusty sky
kindred widget
# lusty sky hmm an array with 1 element won't replicate? but it does with 2 elements is that...

Yes, but not always. Spent the last two days fighting with a component not replicating an array. Component was replicated, resolved correctly on clients, etc. Just no OnReps, and tick printing the array length on client was showing no changes. I vaguely remembered a conversation from around two years ago that sometimes stuff with single properties won't replicate, so I just added a replicated integer. And boom, Array starts working perfectly as intended. Just wondering why this happens.

woven basin
#

In what scenario does GetOwner() throw a fatal error? How can an Actor not have a valid pointer to its own owner?

I've got a BeginPlay function that is doing stuff, and an OnRep is firing.

Error        LogWindows                === Critical error: ===
Error        LogWindows                Fatal error!
Error        LogWindows                Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000168
Error        LogWindows                [Callstack] 0x00007ffcb8293c39 UnrealEditor-Blaster.dll!ResolveObjectHandleNoRead() [D:\Epic Games\UnrealEngine\Engine\Source\Runtime\CoreUObject\Public\UObject\ObjectHandle.h:300]
Error        LogWindows                [Callstack] 0x00007ffcb82a4e6c UnrealEditor-Blaster.dll!AWeapon::SetHUDCarriedAmmo() [D:\Repo\Blaster\Source\Blaster\Weapon\Weapon.cpp:297]
Error        LogWindows                [Callstack] 0x00007ffcb8292123 UnrealEditor-Blaster.dll!UCombatComponent::OnRep_CarriedAmmo() [D:\Repo\Blaster\Source\Blaster\BlasterComponents\CombatComponent.cpp:370]

Line 297 of Weapon.cpp is this:

AActor* Testing = GetOwner();

The issue does not occur on a listen server, obviously as there is no on_rep called. But when I change to 2 players, the issue appears.

I tried googling around, didnt find much...

fathom aspen
#

Owner is a replicated pointer to an actor. You can't guarantee the owner/actor has replicated (is valid on client) when that OnRep fires.

woven basin
#

arh... ok. What is the "best practice" to defend against this scenario?

fathom aspen
#

To have a TryInitialize() function that does what you want in both places (Your OnRep and OnRep_Owner) and ofc makes sure you don't do it twice

woven basin
#

Interesting.

is there somewhere this is documented/discussed in more detail? I just double checked eXi's compendium and I dont see it there at a quick glance. I'm just wondering if there's more to know around this topic...

fathom aspen
#

Nothing really. eXi's compendium is aimed towards introducing you to networking in unreal. You won't discover these stuff until you experience them.

woven basin
#

Fair enough. I'm just keen to understand it some more - I'll have a play around. Thanks.

#

Sorry, maybe I'm missing something obvious - how do I know if the owner has not replicated if I cant actually call GetOwner() since that is causing the crash? What is the mechanism to detect this?

fathom aspen
#

I mean there is nothing beyond what I said. Independent actors have their own net frequency, and as a result has their own rate of replicating stuff. There is no such guarantee that two independent actors have replicated at the same time.

#

There is however for POD types, which if changed at the same frame will replicate at the same time.

fathom aspen
#

OnRep is called when NetGUID resolves into a valid object on client

#

NetGUID is just a globally unique identifier for UObjects

#

And FNames iirc

#

In your case the NetGUID wasn't yet resolved so you was accessing a null object

woven basin
#

ok awesome - i've got something working with that. Greatly appreciated @fathom aspen

twilit radish
fathom aspen
#

It does, not that I tried it though. Wondering for how long it has been a thing

twilit radish
#

No idea.

#

But this is exactly what my struggle always is, it's just impossible to predict what frequency you should set actors at. Especially in many games these days where everything is dynamic.

#

So in theory it sounds extremely nice to have that just be automatically updated 😄

fathom aspen
#

Right, I find that a struggle too. But iirc NetUpdateFrequency is the maximum frequency, so it goes down if it's not considered for replication that much

storm bough
#

So, I managed to get kicking player from session to work. But how I can do some feedback for kicked player? Right now player just lands in default level (main menu) without any explanation or info about kick reason.

fathom aspen
fathom aspen
#

Utilize the options string

#

which is part of the travel URL

twilit radish
#

The default kick implementation in GameSession is really weird. It calls a RPC on the playercontroller that is about to be kicked but the result can never be used because the method isn't virtual, is not exposed to BP and doesn't have any implementation LOL.

fathom aspen
#

Sad day for the GameSession. Yeah it's really sad when you need a function to be virtual and it isn't xD

twilit radish
#

I should PR it xD

#

And give a BP implementation lol

fathom aspen
twilit radish
#

😦

fathom aspen
twilit radish
#

Honestly I’m up for the challenge, never done it before. Although I’ll need to look through the existing PRs first.

#

Don’t really care if they don’t merge it.

fathom aspen
#

Yeah the whole procedure is fun tbh. My first PR was at least, and they ended up accepting it because it was a typo fix lol

#

Now that they accepted it, I have a bunch of them on the way

storm bough
fathom aspen
#

The options string starts after the first ?

storm bough
#

yes, I know about that. Are you suggesting kick reason is already in options?

twilit radish
#

How are you kicking the player?

fathom aspen
fathom aspen
storm bough
#

gamesession->KickPlayer

#

if there is some different way to kick player that gives control over travel, I would like to know

twilit radish
#

Just use an RPC with the kick reason before kicking the player.

#

It’s what the engine does and fails at to properly make useable

storm bough
#

map URL options would be great if I knew how to add options in this particular case. After all, I do not initiate travel - game does that automatically.

twilit radish
#

If you send a RPC to the client with the reason you can just store it somewhere and then retrieve it later on.

#

The engine / game session doesn’t seem to store it.

storm bough
twilit radish
#

For example.

fathom aspen
#

Are you using Steam?

storm bough
#

no, EOS

fathom aspen
#

Ah at least you are using one

storm bough
#

I can modify that plugin, actually

fathom aspen
#

I would look at what EOS does and try to modify it

storm bough
#

(I already did it to remove some dumb bugs)

storm bough
fathom aspen
dim trail
#

does this not work because the gate is on the client?

unknown.png
fathom aspen
#

Gate is a macro that uses a local boolean. So this is ofc won't work as those are different ends.

dim trail
#

better way to do this just use a replicated variable?

fathom aspen
#

Not even that. Pretty sure GAS has its own way to handle that.

dim trail
#

i dont use gas

fathom aspen
#

Ah the names implied that. Then just fire a server RPC on input press that enters the gate.

twilit radish
#

Why is the game session kick system.. The way it is lol.

grizzled stirrup
#

So by marking a member of a struct with NotReplicated it is essentially treated as a local variable correct?

#

And if this member was to be changed on the server but no other members were, the struct would not get replicated down?

shell mantle
#

Im trying to replicate setting the players Skeletal Mesh in runtime but can't seem to figure it out. I tried making a Skeletal Mesh varialbe RepNotify and then set the characters skeletal mesh in there and no luck. I have also tried setting up two different events, one on server one on client, to set the SK and no luck again. Any suggestions?

kindred widget
#

Make a replicated SkeletalMesh pointer. Add OnRep. when OnRep runs set character's Mesh SkeletalMeshComponent to the new SkeletalMesh. Set SkeletalMesh pointer only on the server.

fathom aspen
solar swallow
#

using repnotifies, is there any way to ensure one notfy gets called before another?

fathom aspen
#

No

#

Your systems should be resilient to the replication callbacks order

dim trail
#

Should property check functions be called on the server or the client?
For example, a function that checks if Health > 10

fathom aspen
#

Most probably server. You don't want the client lying about his health and thus not dying. But if that is for some cosmetic stuff then it's not a big deal

twilit radish
#

There's not really a golden rule for it though. It just depends on what you want to do. Something like health is generally better to keep server sided, but it's not weird for a client to check if the health is smaller than a certain threshold and then maybe do something UI related like a flashing healthbar for example.

winged badger
#

With FastArrayItem callbacks going before any OnRep

fathom aspen
winged badger
#

Its a general case

fathom aspen
winged badger
#

If you csnt resolve an object replicated property points to, and you dont have repnofify always obviously that onrep wont fire at all

fathom aspen
#

I should read more through the RepLayout and ObjectReplicator files 😄

winged badger
#

But the order still remains intact

fathom aspen
#

Right right. Makes total sense!

winged badger
#

Note that i would not trust blueprints not to mix up their props

fathom aspen
#

Ah right, totally forgot about those bastards. I could see them as a potential threat

winged badger
#

If you added them in order, and msrked them repnotify in same order and havent rearranged the order sure

#

But bp has some funny serislization quirks

fathom aspen
#

It depends on how the NetDriver gathers props I guess. I would guess the cpp ones go first...

twilit radish
#

They are inserted at random every time you start up Unreal >:D

fathom aspen
#

Yeah that could be the case for the BP ones I believe

#

But I want guarantees 😔

tidal veldt
#

If the client needs to change a replicated variable, should that be done through an RPC to the server?

twilit radish
#

Yes.

fathom aspen
#

If the client wants it to be reflected to others then yes.

twilit radish
#

Clients can only communicate to the server through RPCs.

fathom aspen
#

Server ones to be specific

tidal veldt
#

hm okay

twilit radish
#

Also Wizard I have an idea for a blog post for you. Make a few random multiplayer features and post it as a post with "Here are X ideas to practice building multiplayer features!" 😄

#

I can literally not find a single thing on Google doing this.

fathom aspen
twilit radish
#

Challenges yeah.

fathom aspen
#

That sounds great tbh. benui is doing something similar atm and it sounds cool

#

Thanks for the ideas Wumpus_Heart

tidal veldt
#

make one about removing and adding instances of instancedmeshes from the foliage system in multiplayer

#

then link it to me

#

for... reasons

fathom aspen
#

Lol

twilit radish
#

😉

fathom aspen
#

Yeah it's turning great Thom, yea

twilit radish
#

I should make my own blog and just do challenges my self honestly x)
It's just annoying how little general info there is on the internet about multiplayer or even more fun things like challenges, interactive websites or whatever, when I first started in Unity and wanted to try multiplayer it felt like absolute black magic. Everything seemed like it was impossible to do because of complexity.

#

Then most resources online are just about how to do very specific things or talk about the concepts behind stuff. Which as a beginner back then was absolutely horrible to work with for me.

#

Time to start my own course guys 🤣

fathom aspen
#

Agreed. Not long ago I looked for Unity networking resources and I barely found a few. In Unreal there are much more, but it doesn't usually mean that it's better (you know bad tutorials exist).

#

I'm also pushing you to make your blog, I have enough posts on the list xD

tidal veldt
#

I feel like the unreal ones are so basic that its hardly applyable knowledge

fathom aspen
twilit radish
#

Lol.

fathom aspen
winged badger
# 
    if (const UBlueprintGeneratedClass* BPClass = Cast<UBlueprintGeneratedClass>(GetClass()))
    {
        BPClass->GetLifetimeBlueprintReplicationList(OutLifetimeProps);
    }```
#

something like this replicated BP props

fathom aspen
#

And it's usually at the start

winged badger
#

not for vanilla UObjects

#

then you need to add this by hand

fathom aspen
#

Interesting.

fathom aspen
#

So after an extensive research I found out that UserWidgets persist a seamless travel for the following conclusion:
Upon seamless travel, any UObject (non-Actor) that is outer’d to a persistent Object will also be persistent.

The persistent world is always torn down regardless of the travel type. I couldn't yet prove the above conclusion, but I wrote my findings and assumptions on the topic if you're interested: https://wizardcell.com/unreal/persistent-data/#persistent-non-actor-objects-across-seamless-travel

I also didn't look into the MoviePlayer part yet. Hopefully that will provide me with some useful insights when I do, but for now I can take a break from this 😄

#

Also huge shoutouts to you for pushing me to write this!

gleaming kite
#

Maybe the wrong chat but does the Steam subsystem support cross region lobbies?

twilit flint
#

what dependency do I need to add for macro MARK_PROPERTY_DIRTY_FROM_NAME ?

twilit flint
#

the answer is private "NetCore"

pulsar lotus
#

Hello, how skeletal mesh socket replication works?

When i try to replicate and draw socket position, position on server are incorrect(stays in default position), but animation and socket fully replicated on clients

Green == Server
Pink == Local Player
Blue == Network Player

Size just for visualization

unknown.png
clear island
#

I've noticed a different issue myself which is the socket on the server is correctly where I placed it, but on clients, its not, still not sure whats causing it yet

pulsar lotus
clear island
#

hmm in my case this was already set

clear island
#

its strange, it lets me move it on the red and green axis, but the blue axis, only on the server takes effect

clear island
#

now that I take a closer look, it seems like it does let me move it, but the actor I have attached to this socket does not move to the socket blue axis position for some reason

obtuse field
#

I have HTTP request that returns just 0, without any fields etc. How can I grab this in varest?

gleaming kite
#

Is there a way to know when the playerstate is valid on a listen server? On_Rep playerstate doesnt fire

fossil spoke
#

It will likely be valid immediately after the PlayerController is created.

#

The reason why its delayed for Clients is simply due to it needing to be replicated.

#

But since the Host is the Server, it doesnt need to have it replicated.

gleaming kite
#

Gotcha, thank you. That’s what I meant. So it’s safe to do any logic I need initially on begin play or perhaps on posses?

fossil spoke
#

On Possess would likely be better, but keep in mind thats only called on the Server

gleaming kite
#

Yep. Thank you!

kindred widget
brazen glacier
#

Just wanna double check I'm not missing anything. Replicated variables replicate after construct, right?

For example, I spawn a weapon on server and replicate it. I have a PossessingCharacter variable that's replicated and set to expose on spawn with a value passed in. Yet when I try to access it in Construct, client show null ref. The only way to get this working so I can know what character is "holding" the weapon is to make a repnotify for the variable and call an Initialize function after it updates.

Seems like a poo design choice of the engine because it's counterintuitive and causes many problems and workarounds, but maybe there's a deeper code limitation with not being able to use passed-in variables in a contructor? Am I correct in my assumptions?

marble gazelle
# brazen glacier Just wanna double check I'm not missing anything. Replicated variables replicat...

Expose on spawn means, that if you spawn this actor from blueprint, you'll get a pin to pass in the value to be set.
Aside from that, Construct is called before anything got replicated, so the earliest you should try to read values from replication is BeginPlay. The current state of all replicated values for an actor is sent with it's initial bunch. If you set the value after a new actor channel opened for this actor, it might get replicated later.

brazen glacier
#

Thanks. Thing is, it's not set when accessing from the constructor, even if I did set it by passing it in. Shouldn't require replication to set a var so it's weird.

fathom aspen
#

OnRep is the way, and engine already does that using OnRep_Owner. At the time you attach your weapon to the character, the character gets assigned as Owner.

regal geyser
#

Is it normal to achieve severe rubber banding/character sliding when using default character movement component as a client using steam? There's no issue if both clients have decent hardware/internet connection, but as soon as I try it on my ancient laptop, I practically can't even move. What would be a good approach to fix this issue?

chrome bay
#

So long as you are applying input correctly (via Add Movement Input), you should mostly be fine.

#

Also check if the game runs properly on that device when offline first

regal geyser
#

It runs completely fine, I also tried setting client authoritative movement just to test it, and it fixed all issues but client authoritative movement isn't the way to go. Why it's confusing to me is because I just use the default 3rdPersonBP movement:
But the rubber banding and sliding (character keeps moving even when client doesn't hold any key) is unbearable

unknown.png
pulsar frigate
#

hi, does anyone know what could cause this type of error? everything worked just fine recently on old pc, where server would normally run, it's still old package which was running, also port on pc doesn't seem to be working.

unknown.png unknown.png
latent heart
#

Seems the port on your router is closed.

#

If you've changed computer, it's possible your router setup is broken...

dapper obsidian
#

On GameLift, if I have a fleet with ports 7777-7786 open, how do I specify the port I want a game session to use when I create it?

latent heart
#

How are you creating the game session?

dapper obsidian
#

Via the AWS CLI.

latent heart
#

Are you specifying a map on the command line?

#

Or some sort of URI

#

if you use the console command to change maps, you can do mapname?port=xxxx?otheroption=y?etc=blah

dapper obsidian
#

Hm, looks like I can pass specific arguments to the executable via AWS CLI's --game-properties argument; I'll try that.

gentle bridge
#

Hello, I'm using a full body mocap, I would like to delay the animation of the 1 fronted character to several behind, anyway I could do this ?

fathom aspen
gentle bridge
#

oups

#

may bad, was changing chanel by doing research

#

thxx

dark edge
#

Not sure if this is the place for this, but does anyone here know anything about the general techniques behind WoW's client and backend? Like how their buffs, spells, casting, and movement are done?

#

It feels like it has some prediction but I'm not sure it does. I've never noticed a rollback on anything but movement.

pallid mesa
#

@summer nova ^ I think you looked into this extensively

summer nova
#

@dark edge you have the code on the wow pirate/private servers like MANGos

elfin lintel
#

I'm trying to get my app to integrate with steam using my own steam app ID. I can get a player to connect when I use the general testing ID (480) but not when I use my own steam app ID. When trying to use my own steam app ID I am only changing the value for the app ID in the ini file. Is there any other change I need to make to get it working with my own app ID?

pallid mesa
dark edge
summer nova
#

@dark edge mmos are a whole different thing

#

to begin with, the client does more or less nothing but to play vfx

#

but it depends on the thing

#

for example inventory management is 100% server driven. The client does no logic whatsoever. If you have lag, its slow to rearrange items in your bags

#

for movement its all done clientside, and client sends movement information to the server

#

the server accepts it with no validation

#

damage/effects/etc are completely serverside

#

when damage numbers appear is because the damage was processed on server

dark edge
#

You sure wow doesn't do corrections for movement?

#

So far what you're describing is a bit like if you did ACharacter(CharacterMovementComponent) + a spell/buff/stat system (with NO prediction) + input buffering (the cast timing window), that seem about right?

rocky kestrel
#

This is from inventory component attached to ThirdPerson character. It is replicated component and "Inventory new" is replicated variable.

a225b14f4e65aefc6292321586a60524.png
#

This is from player interface event

45685a805c3b7478664253deca5e8bb2.png
#

This happens in game mode to save

616da1d981919ac25a94373ceab75bce.png
#

Those inventory variables doesnt work but health and location etc works

#

Why is that?

summer nova
#

@dark edge the wow server does absolutely nothing for movement

#

this is done to save performance, no need to raycast against terrain and similar

#

thats why things like speedhacks or flyhacks are quite common

dark edge
#

I wonder why I haven't seen any cheating for a long time

#

maybe they're pretty heavy handed with the banhammer and since wow implies at least a decent amount of investment in the character you'd rather not risk it.

summer nova
#

on wow classic they give 0 fucks

#

botters flying around have been there for a while

#

and moving below the ground

dark edge
#

I'm talking retail, maybe retail has some more stuff

summer nova
#

its the same server

#

mostly

#

its more that they ban people who get caught

#

but botters dont have an issue. new account gets made and the money gets sent to other places quickly

dark edge
#

@summer novahttps://trinitycore.atlassian.net/wiki/spaces/tc/pages/2130106/Spell+handling+in+TC Very interesting

summer nova
#

@whole grove you understand they handle a thousand players in one server

#

or more

#

movement is something that updates every single tick for every single player

dark edge
#

I mean doing wow movement server authoritative wouldn't be insanely hard, but if they don't need to do it, the easier it is for them.

#

You have walking, flying, falling, swimming, and launching/jumping. THat's about it.

#

It's basically the CMC

#

also no collisions between pawns

summer nova
#

it would be insanely hard

#

again, its 1000 players

#

CMC becomes the number 1 perf bottleneck in unreal engine at 100 players (battle royale example)

dark edge
#

Oh it'd be heavy but code wise it wouldn't be anything groundbreaking

summer nova
#

not worth it

#

you could use that cpu time to shove more players, directly lowering your server costs

#

thing is, because you need to buy the game, if there are cheaters they can just be banned

#

and you get extra sales

#

the trinity core and mangos server use to run 5000 players

#

on a beefy machine

#

thats with their fairly atrocious code really. I worked on some experimental tech where we could process replicated movement for 20.000 players

pallid mesa
#

not 20k connections but 20k pawns running around, iirc, right?

summer nova
#

the connections were simulated. getting 20k real players at the same time is not something that can happen lol

twilit radish
#

LOL. That reminds me of Splitgate.

#

To be honest, I would not want to scale a system for up to that many people. Does not sound fun.

buoyant oasis
#

Really struggling with implementing networked functionality and think It’s because I’ve managed to screw up my understanding of what the client should be. Right now I’m thinking of the client more as a visual reflection of the server instead of it’s own instance of the game which should maintain an accurate reflection of the server’s instance. Am I right in thinking I’m wrong?

For example, the client performs an action, the server is told and performs the action on its instance, correcting the client if wrong, the action is then replicated to the other clients, and they perform it.

fathom aspen
#

No, you are not right in thinking you are wrong

twilit radish
#

Clients and the server are their own instances. With the exception of listen servers where a client is the server. The server is responsible for keeping clients in sync with its own view of how a world is. Clients don’t necessarily have to be a perfect reflection of the server though, with for example predicting character movement the client is in the ‘future’ compared to the server. It’s a big mix of a lot of things 😛

summer nova
#

if you can handle a couple thousand players concurrent in your game, that means you as an indie only ever need 1 server for hosting

#

even if its like a 5v5 shooter, if you can stuff 20 matches at once in 1 machine, thats a huge improvement

#

valorant does that for example

#

saves them loads of money

twilit radish
#

The company I work for has a game with a 1vs1 mode, in Unreal terms their ‘worlds’ are a separate thread running compared to other ‘worlds’. Saves a lot of money probably to indeed not need a new instance per 2 players 😛

pallid mesa
summer nova
#

@pallid mesa a mass of pseudoplayers moving randomly

#

each pseudoplayer basically had a small AI script that updated its positions as if it was a real player wandering about. The rest of the engine thought they were real players

#

movement replication was realistic

dim trail
#

does the validate from RPC have the potential to crash the server?

#

it could notify the system to disconnect the client/server who initiated the RPC call.

chrome bay
#

no

#

Well, unless you do something inside it that crashes the server

#

But by itself no

open quail
#

Where can I read the "additional server game options" in the editor preferences? I though they were on the client open parameters but doesnt seem to be the case.

fathom aspen
#

GameMode.OptionsString?

open quail
dim trail
open quail
dapper sundial
#

how do i get a reference to the widget on a client?
I made a reference to the widget as it was created in the character blueprint(the widget shows up on both the client and the server), but the reference is null for the client character and only works on the server

#

i do this, and the GameplayUI only exists on the server

unknown.png
dark edge
#

what are you trying to do

dim trail
#

Can someone explain to me what the reliable and unreliable tags actually do

dark edge
dapper sundial
dark edge
#

Unreliable is just fire and forget.

#

Use reliable for stuff that HAS to happen, and unreliable for stuff that is ok to mostly happen

dim trail
#

One of the networking devs of fortnite said they set all RPCs to unreliable

dark edge
dark edge
#

But they probably don't use RPC for stateful stuff

dim trail
#

Something about it being sorted and issues that come with that, but it’s really just a mystery to me

dapper sundial
dim trail
#

They say it just resends the request but there’s more to it

dark edge
#

or maybe Pawn, depending.

#

Wherever it lives, it does NOT live in a widget

#

widget just DISPLAYS the score

dapper sundial
#

but i can't get the correct widget to display the said score

dark edge
#

K so what's the problem? Have you confirmed that score is replicating correctly?

dapper sundial
#

yes, without the widgets updating, it works fine

worn wagon
graceful flame
# dim trail One of the networking devs of fortnite said they set all RPCs to unreliable

Here's the thing with reliable. If its called "too many times" you could end up overflowing the reliable network buffer because all of those reliable RPCs have to be processed and won't ever be discarded. If that happens the client would automatically disconnect from the session.

So what counts as "too many times"? Probably a few actors calling reliable RPCs on tick or something like that.

dapper sundial
#

this still only updates on server

quasi tide
#

Make sure TeamB Score is replicated

dapper sundial
#

thank you

dapper sundial
#

one more thing, how do i do a similar one for player state(for health, which is on my player state)

#

get player state on the blueprints asks for a player state index, can i just give 0 and 1 for two players?

quasi tide
#

Access controller, access player state.

#

So just call get controller on your pawn. Then just get the player state. I'd recommend making something like this a BPFL

cold moat
#

Guys, a quick doubt about events. I have this replicated event that casts to a component that has a replicated event calling a function. I'm wondering, if I make the first event call the function, it will be replicated? Or maybe having another replicated event on the component calling that function is necessary?

#

I'm laughing so much of that reaction because I feel the same Laugh1

#

Let me rephrase it, I have an event calling another event that calls a function. Both events are replicated, one of the events exists only to call that function. Is it okay having only the first event directly calling the function even if they're not from the same actor? ThinkDerp

rocky kestrel
#

Does anyone know how to set those inventory component variables that server can get those? Calling that function in dedicated server game mode to save.

71437a7e86dc615e25faea32f66416db.png
oak oracle
#

hi devs , "PING" is this time taken for info to reach the server and come back , or only time taken by server to respond to client ?

quasi tide
#

There and back

cold moat
#

I'll take some screenshots when I get home

#

by event I mean custom events, like event dispatchers, and by replicated event, I mean an event that is set replicated and runs on the server (or client etc)

fathom aspen
#

It's hard to tell without seeing code, but seems like the other replicated event is redundant. If the second event is aiming for the same end the first event aims for then no you don't need the second event to be replicated (to be an RPC). @cold moat

wild patio
#

Has anyone here had any issues with Gamelift on any version of Unreal Engine newer than 4.26?

#

4.26 is the newest supported version. I'd like to use a newer version of UE, but don't want to run into any show stopping bugs.

shy yarrow
#

Why casting game mode on begin play in character class work for all clients and server but when pressing button ,it only work for server? I thought that the game mode class only works for the server, but in the test I did in Begin Play, it also works for the clients. why?

8585.png
#

where other parts Gamemode works for clients?

fathom aspen
#

It's "working" because every client on his machine has the BeginPlay event firing on both server and client. On server there is a valid GameMode, but on client there is none

#

For input, it fires locally, i.e. at the local controller level.

#

The host has the local controller at the server so it works for him
Other clients has it client-side so it doesn't

wild patio
#

so the game mode exists on the client, but has no authority and no influence on the game, basically?

fathom aspen
#

No, the GameMode exists server-side only

#

Reread carefully what I wrote

fathom aspen
#

That's why you need to SwitchHasAuthority for example and use authority pin

twilit radish
#

Epic should port the behaviour where derefecering a nullptr crashes the game to BP 👀

fathom aspen
#

Yeah maybe after they make TMaps support replication

latent heart
#

Is that a pig I see? In the sky? with wings?!

shy yarrow
fathom aspen
#

BeginPlay is an actor function

#

In the context of Pawns it does, yes
In the context of HUDs it doesn't. It fires locally
So it depends on which actor are we talking

dark edge
fathom aspen
#

I like how I edit and save

shy yarrow
#

how clients can access to gamemode variables? I mean how can use RPC for that?

latent heart
#

They can't.

fathom aspen
#

You can't.

latent heart
#

Ever.

fathom aspen
#

Like you can't divide by 0 for example

latent heart
#

You can, it just undefined behaviour!

#

😄

fathom aspen
#

Lol

twilit radish
#

The universe explodes.

latent heart
#

I mean, I guess c++ can't handle that.

#

Silly c++.

dark edge
#

On this topic, do you guys put logic in Gamestate or mostly data and do the logic in Gamemode?

latent heart
#

Gamestate is for... state.

#

GameMode is for logic.

dark edge
#

I almost feel like they should have named it GameController and not GameMode

latent heart
#

Some people disagree.

shy yarrow
dark edge
#

To parallel the PlayerController and PlayerState

latent heart
#

It doens't control the game, only the current mode.

twilit radish
#

I always get confused on when to use gamestate and gamemode honestly 😂
Except when I need to replicate something.

latent heart
#

GameFacilitator!

fathom aspen
dark edge
latent heart
#

I'd say game instance is more top dog

#

But it's just very aloof.

fathom aspen
dark edge
#

I like to keep state only in Gamestate. If I find myself gating by authority, it goes in the Gamemode instead usually.

dark edge
shy yarrow
#

so I can use joined player array and use RPC inside the players class, right?

dark edge
#

Or a multicast event in GameState

#

The State of the Game is that it's over, here's your winners. Congratulations

shy yarrow
fathom aspen
quasi tide
#

I use GameMode as the rules of the game. The things that only the server care about. GameState for transmitting data from GameMode to clients.

latent heart
#

Depends on your definition of work!

#

They work, just maybe not as you expected. 😛

shy yarrow
fathom aspen
latent heart
#

Probably not. You should use an ai player state for that maybe?

#

Do ai player states get replicated?!

fathom aspen
#

They do.

quasi tide
#

They should. It is a player state

fathom aspen
#

They are by default at least

shy yarrow
latent heart
#

Wow.

quasi tide
#

Network compendium

fathom aspen
#

Yes. This channel pins

latent heart
#

I think you may be the only person to ever ask for a PDF regarding UE.

fathom aspen