Okay so I have had some troubles getting Steam multiplayer working in Unreal Engine 5.6
I am going to share my current configuration and what is working for me, for reference to anyone else trying to get this working.<\/p>\n\n\n\n
There is still a lingering issue when trying to join sessions hosted on the MacOS from windows, at this stage I am guessing something like firewall blocking the client inbound connections. I don’t have two Mac’s to test Mac -> Mac Connection, however the current state of play is that Windows -> Windows lobbies work fine, MacOS -> Windows lobbies work fine, but Windows -> MacOS lobbies fail to join and timeout.<\/p>\n\n\n\n
DefaultEngine.ini Relevant settings:<\/p>\n\n\n\n
\n[OnlineSubsystem]
DefaultPlatformService=Steam
PollingIntervalInMs=20
bUseBuildIdOverride=True
BuildIdOverride=1<\/p>\n\n\n\n[OnlineSubsystemSteam]
bEnabled=true
SteamDevAppId=3488710
bInitServerOnClient=true
bAllowP2PPacketRelay=true
bVACEnabled=false
bRelaunchInSteam=false
GameServerQueryPort=7777
bUseSteamNetworking=true ; enables SteamSockets path<\/p>\n<\/blockquote>\n\n\n\nSteamSockets must be enabled in Project Plugins.<\/p>\n\n\n\n
I am also using AdvancedSession\/AdvancedSteamSessions, I have a derivative AdvancedFriendsGameInstance class that is then also Derived in Blueprints.<\/p>\n\n\n\n
The reason for a derived class was to add a new Join Session function, I was having some trouble with joining that may have been unrelated, but nevertheless, here is where I have ended up. For science I could go back and test the built in Join Session (maybe later), for now find my full class overwrite below:<\/p>\n\n\n\n
RW_AdvancedGameInstanceCPP.h<\/p>\n\n\n\n
#pragma once\n\n#include \"CoreMinimal.h\"\n#include \"AdvancedFriendsGameInstance.h\" \/\/ AdvancedSessions base GI\n#include \"Interfaces\/OnlineSessionInterface.h\"\n#include \"RW_AdvancedGameInstanceCPP.generated.h\"\n\nUCLASS()\nclass RACEWARS_GREEN_API URW_AdvancedGameInstanceCPP : public UAdvancedFriendsGameInstance\n{\n GENERATED_BODY()\n\npublic:\n \/** Call this from BP with the selected FBlueprintSessionResult *\/\n UFUNCTION(BlueprintCallable, Category = \"Online|Sessions\")\n void JoinSessionFromResult(const FBlueprintSessionResult& SessionResult);\n\nprivate:\n FOnJoinSessionCompleteDelegate JoinSessionCompleteDelegate;\n FDelegateHandle JoinSessionCompleteHandle;\n\n void OnJoinSessionComplete(FName SessionName, EOnJoinSessionCompleteResult::Type Result);\n\n IOnlineSessionPtr GetSessions() const;\n};<\/code><\/pre>\n\n\n\nAnd RW_AdvancedGameInstanceCPP.cpp<\/p>\n\n\n\n
\/\/ Fill out your copyright notice in the Description page of Project Settings.\n\n\n#include \"RW_AdvancedGameInstanceCPP.h\"\n\n#include \"OnlineSubsystem.h\"\n#include \"Interfaces\/OnlineSessionInterface.h\"\n#include \"Kismet\/GameplayStatics.h\"\n#include \"Engine\/Engine.h\"\n\nIOnlineSessionPtr URW_AdvancedGameInstanceCPP::GetSessions() const\n{\n if (IOnlineSubsystem* OSS = IOnlineSubsystem::Get())\n {\n return OSS->GetSessionInterface();\n }\n return nullptr;\n}\n\nvoid URW_AdvancedGameInstanceCPP::JoinSessionFromResult(const FBlueprintSessionResult& SessionResult)\n{\n IOnlineSessionPtr Sessions = GetSessions();\n if (!Sessions.IsValid())\n {\n UE_LOG(LogTemp, Error, TEXT(\"[JoinSessionFromResult] No SessionInterface.\"));\n return;\n }\n\n \/\/ Bind join complete\n JoinSessionCompleteDelegate = FOnJoinSessionCompleteDelegate::CreateUObject(\n this, &URW_AdvancedGameInstanceCPP::OnJoinSessionComplete\n );\n JoinSessionCompleteHandle = Sessions->AddOnJoinSessionCompleteDelegate_Handle(JoinSessionCompleteDelegate);\n\n const FName SessionName = NAME_GameSession; \/\/ Must match your CreateSession name\n const int32 LocalUserNum = 0;\n\n const bool bJoinStarted = Sessions->JoinSession(LocalUserNum, SessionName, SessionResult.OnlineResult);\n UE_LOG(LogTemp, Log, TEXT(\"[JoinSessionFromResult] JoinSession started: %s\"), bJoinStarted ? TEXT(\"true\") : TEXT(\"false\"));\n\n if (!bJoinStarted)\n {\n Sessions->ClearOnJoinSessionCompleteDelegate_Handle(JoinSessionCompleteHandle);\n }\n}\n\nvoid URW_AdvancedGameInstanceCPP::OnJoinSessionComplete(FName SessionName, EOnJoinSessionCompleteResult::Type Result)\n{\n IOnlineSessionPtr Sessions = GetSessions();\n if (Sessions.IsValid())\n {\n Sessions->ClearOnJoinSessionCompleteDelegate_Handle(JoinSessionCompleteHandle);\n }\n\n UE_LOG(LogTemp, Log, TEXT(\"[OnJoinSessionComplete] Result: %d (0=Success)\"), (int32)Result);\n\n if (Result != EOnJoinSessionCompleteResult::Success)\n {\n UE_LOG(LogTemp, Warning, TEXT(\"[OnJoinSessionComplete] Join failed.\"));\n return;\n }\n\n \/\/ Resolve Steam connect string and force ABSOLUTE travel\n FString ConnectString;\n#if ENGINE_MAJOR_VERSION >= 5\n const bool bHasConnect = Sessions->GetResolvedConnectString(SessionName, ConnectString, NAME_GamePort);\n#else\n const bool bHasConnect = Sessions->GetResolvedConnectString(SessionName, ConnectString);\n#endif\n\n if (!bHasConnect || ConnectString.IsEmpty())\n {\n UE_LOG(LogTemp, Error, TEXT(\"[OnJoinSessionComplete] No ConnectString resolved.\"));\n return;\n }\n\n UE_LOG(LogTemp, Log, TEXT(\"[OnJoinSessionComplete] Resolved ConnectString: %s\"), *ConnectString);\n\n if (APlayerController* PC = UGameplayStatics::GetPlayerController(GetWorld(), 0))\n {\n \/\/ Critical: ABSOLUTE travel prevents appending your current MainMenu map path\n PC->ClientTravel(ConnectString, TRAVEL_Absolute);\n }\n else\n {\n UE_LOG(LogTemp, Error, TEXT(\"[OnJoinSessionComplete] No PlayerController.\"));\n }\n}<\/code><\/pre>\n\n\n\n<\/p>\n\n\n\n
Beyond this, I am using the standard CreateAdvancedSession blueprint node, along with the FindSessionsAdvanced and my custom JoinSessionfromResult function. I also call the custom join function for “Event OnSessionInviteAccepted”<\/p>\n\n\n\n
One crucial point to make is that session destruction is not being handled well by default, particularly as a client in a session, if the host quits\/ends session the client does not seem to destroy the session, so if the client was then to try host or join a session they may fail due to not being able to do so while already in a game session.<\/p>\n\n\n\n
I have added a “Destroy Session” infront of all the create\/join sessions but suspect there is a cleaner method that can destroy the sessions when leaving. Will continue looking into that.<\/p>\n\n\n\n