Ue4C++Replay详细编写案例

好的，下面是一个简单的Ue4 C++ Replay编写案例：

1. 首先，在UE4中创建一个新的C++项目，并创建一个名为MyGameInstance的GameInstance子类。

2. 在MyGameInstance.h文件中添加以下代码：

#pragma once
#include "Engine/GameInstance.h"
#include "MyGameInstance.generated.h"

UCLASS()
class MYPROJECT_API UMyGameInstance : public UGameInstance
{
    GENERATED_BODY()
public:
    UFUNCTION(BlueprintCallable)
    void StartRecording();

    UFUNCTION(BlueprintCallable)
    void StopRecording();

    UFUNCTION(BlueprintCallable)
    void StartReplay();

private:
    FString ReplayFilename;
};

3. 在MyGameInstance.cpp文件中实现StartRecording、StopRecording和StartReplay函数。下面是一个简单的实现示例：

#include "MyGameInstance.h"
#include "Engine/Engine.h"
#include "EngineUtils.h"
#include "GameFramework/PlayerController.h"
#include "Misc/Paths.h"
#include "Misc/FileHelper.h"
#include "Engine/LocalPlayer.h"
#include "GameFramework/PlayerState.h"
#include "GameFramework/GameStateBase.h"
#include "GameFramework/WorldSettings.h"

void UMyGameInstance::StartRecording()
{
    FString CurrentDateTime = FDateTime::Now().ToString(TEXT("%Y-%m-%d-%H-%M-%S"));
    ReplayFilename = FPaths::ProjectSavedDir() / FString(TEXT("Replays/")) + CurrentDateTime + TEXT(".replay");

    for (TActorIterator<APlayerController> It(GetWorld()); It; ++It)
    {
        APlayerController* PlayerController = *It;
        if (PlayerController->IsLocalPlayerController())
        {
            ULocalPlayer* LocalPlayer = Cast<ULocalPlayer>(PlayerController->Player);
            if (LocalPlayer)
            {
                FString AdditionalData = FString::Printf(TEXT("PlayerName=%s"), *LocalPlayer->GetPlayerName());
                GetWorld()->DemoNetDriver->StartRecording(ReplayFilename, false, AdditionalData);
                break;
            }
        }
    }
}

void UMyGameInstance::StopRecording()
{
    GetWorld()->DemoNetDriver->StopRecording();
}

void UMyGameInstance::StartReplay()
{
    if (FFileHelper::FileExists(*ReplayFilename))
    {
        for (TActorIterator<APlayerController> It(GetWorld()); It; ++It)
        {
            APlayerController* PlayerController = *It;
            if (PlayerController->IsLocalPlayerController())
            {
                ULocalPlayer* LocalPlayer = Cast<ULocalPlayer>(PlayerController->Player);
                if (LocalPlayer)
                {
                    FString AdditionalData = FString::Printf(TEXT("PlayerName=%s"), *LocalPlayer->GetPlayerName());
                    GetWorld()->DemoNetDriver->PlayDemoFromFile(ReplayFilename, AdditionalData);
                    break;
                }
            }
        }
    }
}

4. 在UE4中创建一个新的Blueprint类，并将其命名为ReplayActor。在ReplayActor中添加以下代码：

UCLASS()
class MYPROJECT_API AReplayActor : public AActor
{
    GENERATED_BODY()
public:
    AReplayActor();

protected:
    virtual void BeginPlay() override;

private:
    UPROPERTY(VisibleAnywhere)
    UStaticMeshComponent* StaticMeshComponent;

    UPROPERTY(EditAnywhere)
    UMaterialInterface* Material;

    void OnReplayFinished();
};

5. 在ReplayActor.cpp文件中实现OnReplayFinished和BeginPlay函数。下面是一个简单的实现示例：

#include "ReplayActor.h"
#include "Components/StaticMeshComponent.h"
#include "Materials/MaterialInterface.h"
#include "Kismet/GameplayStatics.h"
#include "MyGameInstance.h"

AReplayActor::AReplayActor()
{
    PrimaryActorTick.bCanEverTick = false;

    StaticMeshComponent = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("StaticMeshComponent"));
    StaticMeshComponent->SetCollisionEnabled(ECollisionEnabled::NoCollision);
    RootComponent = StaticMeshComponent;
}

void AReplayActor::BeginPlay()
{
    Super::BeginPlay();

    if (UMyGameInstance* GameInstance = Cast<UMyGameInstance>(GetGameInstance()))
    {
        FDelegateHandle ReplayFinishedHandle = GameInstance->GetWorld()->AddOnWorldCleanup(FWorldCleanup::FOnWorldCleanupDelegate::CreateUObject(this, &AReplayActor::OnReplayFinished));
    }

    if (Material)
    {
        StaticMeshComponent->SetMaterial(0, Material);
    }
}

void AReplayActor::OnReplayFinished()
{
    Destroy();
}

6. 在UE4中创建一个新的关卡，并将其命名为ReplayLevel。在ReplayLevel中添加一个ReplayActor，并将其Material属性设置为一个你喜欢的材质。

7. 在UE4中创建一个新的蓝图，并将其命名为ReplayController。在ReplayController中添加以下事件：

- Event Begin Play：调用MyGameInstance的StartRecording函数来开始记录Replay。

- Input Action Replay：调用MyGameInstance的StartReplay函数来开始回放Replay。

8. 在ReplayController中添加一个Input Action，并将其命名为Replay。在Replay Action的Details面板中将Key设置为R。

9. 在UE4中运行ReplayLevel，并在ReplayController蓝图中按下R键来开始记录Replay。完成后，按下R键再次开始回放Replay。

上面是一个简单的UE4 C++ Replay编写案例。您可以根据您的需求和项目的要求进行修改和扩展。