[TIL] 2026-03-11 | 멀티플레이 채팅 구현

Unreal Engine 멀티플레이어 게임 개발 2-2

1. WHAT

작성한 채팅 메시지는 일단 서버로 전송

서버는 전송 받은 메세지를 다시 클라이언트들에게 전송

 

2. HOW

- 채팅 메시지 출력

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/PlayerController.h"
#include "CXPlayerController.generated.h"

class UCXChatInput;

UCLASS()
class CHATX_API ACXPlayerController : public APlayerController
{
	GENERATED_BODY()
	
public:

	...
    
	UFUNCTION(Client,Reliable)
	void ClientRPCPrintChatMessageString(const FString& InChatMessageString);
	UFUNCTION(Server,Reliable)
	void ServerRPCPrintChatMessageString(const FString& InChatMessageString);

	...
};

#include "Player/CXPlayerController.h"
#include "UI/CXChatInput.h"
#include "Kismet/KismetSystemLibrary.h"
#include "ChatX.h"
#include "EngineUtils.h"

void ACXPlayerController::BeginPlay()
{
    Super::BeginPlay();
    // 로컬일때만 위젯을 생성해서 보여준다.
    if(IsLocalController() == false)
    {
        return;
    }
    FInputModeUIOnly InputModeUIOnly;
    SetInputMode(InputModeUIOnly);

    if (IsValid(ChatInputWidgetClass) == true)
    {
        ChatInputWidgetInstance=CreateWidget<UCXChatInput>(this, ChatInputWidgetClass);
        if (IsValid(ChatInputWidgetInstance) == true)
        {
            ChatInputWidgetInstance->AddToViewport();
        }
    }
}

// 1. 클라이언트가 입력
void ACXPlayerController::SetChatMessageString(const FString& InChatMessageString)
{
    ChatMessageString = InChatMessageString;
    //PrintChatMessageString(ChatMessageString);
    if (IsLocalController() == true)
    {
        ServerRPCPrintChatMessageString(InChatMessageString);
    }
}
// 4. 클라이언트 화면에 출력
void ACXPlayerController::PrintChatMessageString(const FString& InChatMessageString)
{
    //UKismetSystemLibrary::PrintString(this, InChatMessageString, true, true, FLinearColor::Green, 5.0f);

    //FString NetModeString = ChatXFunctionLibrary::GetNetModeString(this);
    //FString CombinedMessageString = FString::Printf(TEXT("[%s] %s"), *NetModeString, *InChatMessageString);
    //ChatXFunctionLibrary::MyPrintString(this, CombinedMessageString, 10.f);

    ChatXFunctionLibrary::MyPrintString(this, InChatMessageString, 10.f);
}
// 2. 서버 RPC 수행. 클라이언트 RPC 호출
void ACXPlayerController::ServerRPCPrintChatMessageString_Implementation(const FString& InChatMessageString)
{
    for(TActorIterator<ACXPlayerController> It(GetWorld()); It; ++It)
    {
        ACXPlayerController* CXPlayerController = *It;
        if(IsValid(CXPlayerController) == true)
        {
            CXPlayerController->ClientRPCPrintChatMessageString(InChatMessageString);
        }
    }
}
// 3. 클라이언트 RPC 수행
void ACXPlayerController::ClientRPCPrintChatMessageString_Implementation(const FString& InChatMessageString)
{
    PrintChatMessageString(InChatMessageString);
}

 

채팅을 치면 모든 클라이언트 화면에 보이게 된다.

 

- 접속하면 로그인 알리기

NetMulticast RPC를 통한 서버 접속 알리기 👉Game State

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/GameStateBase.h"
#include "CXGameStateBase.generated.h"

UCLASS()
class CHATX_API ACXGameStateBase : public AGameStateBase
{
	GENERATED_BODY()

public:
    UFUNCTION(NetMulticast, Reliable)
    void MulticastRPCBroadcastLoginMessage(const FString& InNameString = FString(TEXT("XXXXXX")));
	
};

#include "Game/CXGameStateBase.h"
#include "Kismet/GameplayStatics.h"
#include "Player/CXPlayerController.h"

void ACXGameStateBase::MulticastRPCBroadcastLoginMessage_Implementation(const FString& InNameString)
{
    if (HasAuthority() == false) // 서버가 아님
    {
        APlayerController* PC = UGameplayStatics::GetPlayerController(GetWorld(), 0); // 로컬 컨트롤러
        if (IsValid(PC) == true)
        {
            ACXPlayerController* CXPC = Cast<ACXPlayerController>(PC);
            if (IsValid(CXPC) == true)
            {
                FString NotificationString = InNameString + TEXT(" has joined the game.");
                CXPC->PrintChatMessageString(NotificationString);
            }
        }
    }
}

 

Game Mode에서 OnPostLogin(AController* NewPlayer) 사용

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/GameModeBase.h"
#include "CXGameModeBase.generated.h"

UCLASS()
class CHATX_API ACXGameModeBase : public AGameModeBase
{
	GENERATED_BODY()

public:
    virtual void OnPostLogin(AController* NewPlayer) override;
	
};

#include "CXGameModeBase.h"
#include "CXGameStateBase.h"

void ACXGameModeBase::OnPostLogin(AController* NewPlayer)
{
    Super::OnPostLogin(NewPlayer);

    ACXGameStateBase* CXGameStateBase = GetGameState<ACXGameStateBase>();
    if(IsValid(CXGameStateBase) == true)
    {
        CXGameStateBase->MulticastRPCBroadcastLoginMessage(TEXT("zzageuli")); // 임시 이름
    }
}