언리얼 소스코드 분석 UWorld::ServerTravel 작성중

World의 Server Travel는 Game Mode의 ProcessServerTravel을 호출

bool UWorld::ServerTravel(const FString& FURL, bool bAbsolute, bool bShouldSkipGameNotify)
{
	AGameModeBase* GameMode = GetAuthGameMode();
	
	if (GameMode != nullptr && !GameMode->CanServerTravel(FURL, bAbsolute))
	{
		return false;
	}

	// Set the next travel type to use
	NextTravelType = bAbsolute ? TRAVEL_Absolute : TRAVEL_Relative;

	// if we're not already in a level change, start one now
	// If the bShouldSkipGameNotify is there, then don't worry about seamless travel recursion
	// and accept that we really want to travel
	if (NextURL.IsEmpty() && (!IsInSeamlessTravel() || bShouldSkipGameNotify))
	{
		NextURL = FURL;
		if (GameMode != NULL)
		{
			// Skip notifying clients if requested
			if (!bShouldSkipGameNotify)
			{
				GameMode->ProcessServerTravel(FURL, bAbsolute);
			}
		}
		else
		{
			NextSwitchCountdown = 0;
		}
	}

	return true;
}

ServerTravel에서 ProcessClientTravel을 호출

void AGameModeBase::ProcessServerTravel(const FString& URL, bool bAbsolute)
{
#if WITH_SERVER_CODE
	StartToLeaveMap();

	UE_LOG(LogGameMode, Log, TEXT("ProcessServerTravel: %s"), *URL);
	UWorld* World = GetWorld();
	check(World);
	FWorldContext& WorldContext = GEngine->GetWorldContextFromWorldChecked(World);

	// Force an old style load screen if the server has been up for a long time so that TimeSeconds doesn't overflow and break everything
	bool bSeamless = (bUseSeamlessTravel && GetWorld()->TimeSeconds < 172800.0f); // 172800 seconds == 48 hours

	// Compute the next URL, and pull the map out of it. This handles short->long package name conversion
	FURL NextURL = FURL(&WorldContext.LastURL, *URL, bAbsolute ? TRAVEL_Absolute : TRAVEL_Relative);

	PRAGMA_DISABLE_DEPRECATION_WARNINGS
	FGuid NextMapGuid = UEngine::GetPackageGuid(FName(*NextURL.Map), GetWorld()->IsPlayInEditor());
	PRAGMA_ENABLE_DEPRECATION_WARNINGS

	// Notify clients we're switching level and give them time to receive.
	FString URLMod = NextURL.ToString();
	PRAGMA_DISABLE_DEPRECATION_WARNINGS
	APlayerController* LocalPlayer = ProcessClientTravel(URLMod, NextMapGuid, bSeamless, bAbsolute);
	PRAGMA_ENABLE_DEPRECATION_WARNINGS

	World->NextURL = URLMod;
	ENetMode NetMode = GetNetMode();

	if (bSeamless)
	{
		World->SeamlessTravel(World->NextURL, bAbsolute);
		World->NextURL = TEXT("");
	}
	else
	{
		// Switch immediately if not networking.
		if (NetMode != NM_DedicatedServer && NetMode != NM_ListenServer)
		{
			World->NextSwitchCountdown = 0.0f;
		}

		GEngine->IncrementGlobalNetTravelCount();
		GEngine->SaveConfig();
	}
#endif // WITH_SERVER_CODE
}

ProcessClientTravel에서, 존재하는 각각의 PlayerController에 ClientTravel을 실행

APlayerController* AGameModeBase::ProcessClientTravel(FString& FURL, bool bSeamless, bool bAbsolute)
{
	// We call PreClientTravel directly on any local PlayerPawns (ie listen server)
	APlayerController* LocalPlayerController = nullptr;
	for (FConstPlayerControllerIterator Iterator = GetWorld()->GetPlayerControllerIterator(); Iterator; ++Iterator)
	{
		if (APlayerController* PlayerController = Iterator->Get())
		{
			if (Cast<UNetConnection>(PlayerController->Player) != nullptr)
			{
				// Remote player
				PlayerController->ClientTravel(FURL, TRAVEL_Relative, bSeamless);
			}
			else
			{
				// Local player
				LocalPlayerController = PlayerController;
				PlayerController->PreClientTravel(FURL, bAbsolute ? TRAVEL_Absolute : TRAVEL_Relative, bSeamless);
			}
		}
	}

	return LocalPlayerController;
}

Server의 PlayerController는 Client로 RPC인, ClientTravelInternal을 호출

void APlayerController::ClientTravelInternal_Implementation(const FString& URL, ETravelType TravelType, bool bSeamless, FGuid MapPackageGuid)
{
	UWorld* World = GetWorld();

	// Warn the client.
	PreClientTravel(URL, TravelType, bSeamless);

	if (bSeamless && TravelType == TRAVEL_Relative)
	{
		World->SeamlessTravel(URL);
	}
	else
	{
		if (bSeamless)
		{
			UE_LOG(LogPlayerController, Warning, TEXT("Unable to perform seamless travel because TravelType was %i, not TRAVEL_Relative"), int32(TravelType));
		}
		// Do the travel.
		GEngine->SetClientTravel(World, *URL, (ETravelType)TravelType);
	}
}

GEngine은 Player Controller 헤더 파일에도 선언되어있지 않은 것을 보니

static으로 전역 선언되어있는 것인가..? 

(작성중)