C++ - Configuring the Struct Operator "<<"

//Example Code;

USTRUCT(BlueprintType)

struct FMapInformation

{

GENERATED_USTRUCT_BODY()

public:

TEnumAsByte<ETileType::Type> TileType;

FVector TileLocation;

friend FArchive& operator << (FArchive& Ar, FMapInformation& OtherInfo)

{

Ar << OtherInfo.TileType << OtherInfo.TileLocation;

return Ar;

}

};

Must be specified as reference unconditionally!!

• friend FArchive& operator << (FArchive& Ar, FMapInformation& OtherInfo)

Otherwise there will be problems.

UE4,C++ - Save Game Data With C++

Saving Your Game with C++

Create a SaveGame Object

The SaveGame class sets up an object that can be used as a target for the saving and loading functions declared in Kismet/GameplayStatics.h.

You can create a new class based on SaveGame using the C++ Class Wizard.

In this example, the new SaveGame class is called MySaveGame.

Header

In the header file for your SaveGame object, you can declare any variables you want your SaveGame to store.

UPROPERTY(VisibleAnywhere, Category = Basic)
FString PlayerName;

In this example, there are also variables declared that will be used to store default values for the SaveSlotName and theUserIndex, so that each class that saves to this SaveGame object will not have to independently set those variables. This step is optional, and will cause there to be one save slot that gets overwritten if the default values are not changed.

MySaveGame.h

// Copyright 1998-2017 Epic Games, Inc. All Rights Reserved.

#pragma once

#include "GameFramework/SaveGame.h"
#include "MySaveGame.generated.h"

/**
 * 
 */
UCLASS()
class [PROJECTNAME]_API UMySaveGame : public USaveGame
{
    GENERATED_BODY()

    public:

    UPROPERTY(VisibleAnywhere, Category = Basic)
    FString PlayerName;

    UPROPERTY(VisibleAnywhere, Category = Basic)
    FString SaveSlotName;

    UPROPERTY(VisibleAnywhere, Category = Basic)
    uint32 UserIndex;

    UMySaveGame();
};

Source

Generally, the SaveGame object's source file does not need any particular code to function, unless your particular save system has additional functionality you would like to set up here.

This example does define the values of SaveSlotName and UserIndex in the class constructor, so they can be read out and used by other gameplay classes.

MySaveGame.cpp

// Copyright 1998-2017 Epic Games, Inc. All Rights Reserved.

#include "[ProjectName].h"
#include "MySaveGame.h"

UMySaveGame::UMySaveGame()
{
    SaveSlotName = TEXT("TestSaveSlot");
    UserIndex = 0;
}

Module Header File

To be able to easily access both your SaveGame object and the creating, saving, and loading functions from GameplayStatics, you should add the following lines to your game module's header file, under any other #include statements. Your module header file will be named [ProjectName].h.

MyProject.h

#include "MySaveGame.h"
#include "Kismet/GameplayStatics.h"

Ensure that these #include statements are added after #include "Engine.h" as the compilation will fail otherwise

Saving a Variable

Whenever you want to save out a variable to your SaveGame object, you must create an instance of your SaveGame object, and then set the variable within it.

PlayerName = TEXT("PlayerOne");
UMySaveGame* SaveGameInstance = Cast<UMySaveGame>(UGameplayStatics::CreateSaveGameObject(UMySaveGame::StaticClass()));
SaveGameInstance->PlayerName = MyPlayerName;
UGameplayStatics::SaveGameToSlot(SaveGameInstance, SaveGameInstance->SaveSlotName, SaveGameInstance->UserIndex);

Loading a Variable

To load a variable, you must first load the SaveGame object using UGameplayStatics::LoadGameFromSlot. This creates a new instance of the SaveGame object.

Again, in this case, an empty SaveGame object is first created, so the default SaveSlotName and UserIndex can be read from it. This is an optional step and may not apply in all game implementations.

Once the new SaveGame object has been loaded from the hard drive, the variable values can be read from it and assigned to the necessary Actors or classes, or used directly as shown here.

UMySaveGame* LoadGameInstance = Cast<UMySaveGame>(UGameplayStatics::CreateSaveGameObject(UMySaveGame::StaticClass()));
LoadGameInstance = Cast<UMySaveGame>(UGameplayStatics::LoadGameFromSlot(LoadGameInstance->SaveSlotName, LoadGameInstance->UserIndex));
FString PlayerNameToDisplay = LoadGameInstance->PlayerName;
if (GEngine)
{
    GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Yellow, PlayerNameToDisplay);
}

출처 : https://docs.unrealengine.com/en-us/Gameplay/SaveGame/Code

언리얼 홈페이지.