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Device Management and Multiplayer Plugin

Unreal Engine’s native local multiplayer management lacks the flexibility to handle dynamic controller connections and disconnections and the rapid reassignment of players to gameplay entities (e.g., team management, slot reassignment). The goal was to create a centralized system that could be reused across projects without duplicating code in GameMode or PlayerController.

Technical Approach & Architecture

• Using a UGameInstanceSubsystem to centralize functions and events throughout the entire game, as well as a map that links the equipment to the players in the game.
• Implementation of the Unreal framework with controller connection events from IPlatformInputDeviceMapper.

DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnPlayerConnected, FPlatformUserId, Platform);
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnPlayerDeConnected, FPlatformUserId, Platform);
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnPlayerReConnected, FPlatformUserId, Platform);
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnPlayerRemoved, FPlatformUserId, Platform);

void UCMSubsystem::OnConnectionChange(EInputDeviceConnectionState NewConnectionState, FPlatformUserId PlatformUserID,
                                      FInputDeviceId InputDeviceID)
{
    switch (NewConnectionState) {
        case EInputDeviceConnectionState::Connected:
		//Verifie si le joueur existe deja
		if (ConnectedPlayers.Contains(PlatformUserID))
		{
			//Si le joueur existe, update l'identifant des controles
			auto& Data = ConnectedPlayers[PlatformUserID].DeviceIds;
			if (!Data.Contains(InputDeviceID))
			{
				Data.Add(InputDeviceID);
			}
			OnPlayerConnected.Broadcast(PlatformUserID);
		}
		else
		{
			//Verifie si un local player existe deja
			if (APlayerController* PC = UGameplayStatics::GetPlayerControllerFromPlatformUser(GetWorld(), PlatformUserID))
			{
				//Ajoute dans la liste
				FControllerData Data;
				Data.DeviceIds.Add(InputDeviceID);
				Data.Player = PC->GetLocalPlayer();
				ConnectedPlayers.Add(PlatformUserID, Data);
				//Restat le playe si pas de pawn si in game
			}
			else
			{
				//verifie si joueur max n'est pas atteind
				if (ConnectedPlayers.Num() < UControllersSettings::Get()->MaxPlayer)
				{
					FControllerData Data;
					Data.DeviceIds.Add(InputDeviceID);
					ConnectedPlayers.Add(PlatformUserID, Data);
					
					OnPlayerConnected.Broadcast(PlatformUserID);
					break;
				}
			}
		}
		break;
	}
}

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