unrealengine异步加载关卡参考笔记

简书链接:unrealengine异步加载关卡参考笔记
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第一种：

创建一个c++游戏实例然后蓝图继承，然后设置widget 就行，缺点：测试不能加载widget动画
635HQVVGSSCQ7WRJLRC%X15.jpg

void ULoadScreenGameInstance::Init()
{
	Super::Init();

	FCoreUObjectDelegates::PreLoadMap.AddUObject(this, &ULoadScreenGameInstance::BeginLoadingScreen);
	FCoreUObjectDelegates::PostLoadMapWithWorld.AddUObject(this, &ULoadScreenGameInstance::EndLoadingScreen);
}

void ULoadScreenGameInstance::BeginLoadingScreen(const FString& MapName)
{
	FLoadingScreenAttributes LoadingScreen;

	LoadingScreen.bAutoCompleteWhenLoadingCompletes = false; //在播放完所有电影并完成加载后，加载屏幕将消失
	LoadingScreen.bWaitForManualStop = false; //一直播放movies,除非直到手动停止
	LoadingScreen.bMoviesAreSkippable = false; //加载完成后是否允许通过单击加载屏幕来跳过电影
	LoadingScreen.MinimumLoadingScreenDisplayTime = 2.0f; // movie最少播放时间
	//LoadingScreen.PlaybackType = EMoviePlaybackType::MT_Looped;

	LoadingScreen.WidgetLoadingScreen = FLoadingScreenAttributes::NewTestLoadingScreenWidget(); // movie不存在时，显示的widget

	if (LoadingWidget != nullptr)
	{
		CurrentWidget = CreateWidget<UUserWidget>(this, LoadingWidget);
		TSharedPtr<SWidget> LoadScreen = CurrentWidget->TakeWidget();
		LoadingScreen.WidgetLoadingScreen = LoadScreen;
		OnLoadingWidgetSuccess(CurrentWidget);
		UE_LOG(LogTemp, Warning, TEXT("LoadWidgetSuccess"));
	}
	else
	{
		UE_LOG(LogTemp, Warning, TEXT("LoadingWidget == nullptr"));
	}
	//LoadingScreen.MoviePaths.Add("squad_intro_movie");
	GetMoviePlayer()->SetupLoadingScreen(LoadingScreen);
}

void ULoadScreenGameInstance::EndLoadingScreen_Implementation(UWorld* LoadedWorld)
{
	UE_LOG(LogTemp, Warning, TEXT("LoadSuccess"));
	GetMoviePlayer()->StopMovie();
}

第二种

b站视频老外的，则需要调整一个配置，打开uproject文件修改LoadingPhase为PreLoadingScreen,
这方面参考https://blog.csdn.net/pp1191375192/article/details/103139304/

{
	"FileVersion": 3,
	"EngineAssociation": "5.2",
	"Category": "",
	"Description": "",
	"Modules": [
		{
			"Name": "CppDigitalTwn",
			"Type": "Runtime",
			"LoadingPhase": "Default",

老外的代码


#include "ActionRPGLoadingScreen.h"
#include "SlateBasics.h"
#include "SlateExtras.h"
#include "MoviePlayer.h"
#include "SThrobber.h"

// This module must be loaded "PreLoadingScreen" in the .uproject file, otherwise it will not hook in time!
struct FRPGLoadingScreenBrush : public FSlateDynamicImageBrush, public FGCObject
{
	FRPGLoadingScreenBrush(const FName InTextureName, const FVector2D& InImageSize)
		: FSlateDynamicImageBrush(InTextureName, InImageSize)
	{
		SetResourceObject(LoadObject<UObject>(NULL, *InTextureName.ToString()));
	}

	virtual void AddReferencedObjects(FReferenceCollector& Collector)
	{
		if (UObject* CachedResourceObject = GetResourceObject())
		{
			Collector.AddReferencedObject(CachedResourceObject);
		}
	}
};

class SRPGLoadingScreen : public SCompoundWidget
{
public:
	SLATE_BEGIN_ARGS(SRPGLoadingScreen) {}
	SLATE_END_ARGS()

	void Construct(const FArguments& InArgs)
	{
		// Load version of the logo with text baked in, path is hardcoded because this loads very early in startup
		static const FName LoadingScreenName(TEXT("/Game/UI/T_ActionRPG_TransparentLogo.T_ActionRPG_TransparentLogo"));

		LoadingScreenBrush = MakeShareable(new FRPGLoadingScreenBrush(LoadingScreenName, FVector2D(1024, 256)));
		
		FSlateBrush *BGBrush = new FSlateBrush();
		BGBrush->TintColor = FLinearColor(0.034f, 0.034f, 0.034f, 1.0f);

		ChildSlot
			[
			SNew(SOverlay)
			+ SOverlay::Slot()
			.HAlign(HAlign_Fill)
			.VAlign(VAlign_Fill)
			[
				SNew(SBorder)	
				.BorderImage(BGBrush)
			]
			+SOverlay::Slot()
			.HAlign(HAlign_Center)
			.VAlign(VAlign_Center)
			[
				SNew(SImage)
				.Image(LoadingScreenBrush.Get())
			]
			+SOverlay::Slot()
			.HAlign(HAlign_Fill)
			.VAlign(VAlign_Fill)
			[
				SNew(SVerticalBox)
				+SVerticalBox::Slot()
				.VAlign(VAlign_Bottom)
				.HAlign(HAlign_Right)
				.Padding(FMargin(10.0f))
				[
					SNew(SThrobber)
					.Visibility(this, &SRPGLoadingScreen::GetLoadIndicatorVisibility)
				]
			]
		];
	}

private:
	/** Rather to show the ... indicator */
	EVisibility GetLoadIndicatorVisibility() const
	{
		bool Vis =  GetMoviePlayer()->IsLoadingFinished();
		return GetMoviePlayer()->IsLoadingFinished() ? EVisibility::Collapsed : EVisibility::Visible;
	}
	
	/** Loading screen image brush */
	TSharedPtr<FSlateDynamicImageBrush> LoadingScreenBrush;
};

class FActionRPGLoadingScreenModule : public IActionRPGLoadingScreenModule
{
public:
	virtual void StartupModule() override
	{
		// Force load for cooker reference
		LoadObject<UObject>(nullptr, TEXT("/Game/UI/T_ActionRPG_TransparentLogo.T_ActionRPG_TransparentLogo") );

		if (IsMoviePlayerEnabled())
		{
			CreateScreen();
		}
	}
	
	virtual bool IsGameModule() const override
	{
		return true;
	}

	virtual void StartInGameLoadingScreen(bool bPlayUntilStopped, float PlayTime) override
	{
		FLoadingScreenAttributes LoadingScreen;
		LoadingScreen.bAutoCompleteWhenLoadingCompletes = !bPlayUntilStopped;
		LoadingScreen.bWaitForManualStop = bPlayUntilStopped;
		LoadingScreen.bAllowEngineTick = bPlayUntilStopped;
		LoadingScreen.MinimumLoadingScreenDisplayTime = PlayTime;
		LoadingScreen.WidgetLoadingScreen = SNew(SRPGLoadingScreen);
		GetMoviePlayer()->SetupLoadingScreen(LoadingScreen);
	}

	virtual void StopInGameLoadingScreen() override
	{
		GetMoviePlayer()->StopMovie();
	}

	virtual void CreateScreen()
	{
		FLoadingScreenAttributes LoadingScreen;
		LoadingScreen.bAutoCompleteWhenLoadingCompletes = true;
		LoadingScreen.MinimumLoadingScreenDisplayTime = 3.f;
		LoadingScreen.WidgetLoadingScreen = SNew(SRPGLoadingScreen);
		GetMoviePlayer()->SetupLoadingScreen(LoadingScreen);
	}

};

IMPLEMENT_GAME_MODULE(FActionRPGLoadingScreenModule, ActionRPGLoadingScreen);

然后通过纯蓝图c++代码调用它

URPGBlueprintLibrary::URPGBlueprintLibrary(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
{
}

void URPGBlueprintLibrary::PlayLoadingScreen(bool bPlayUntilStopped, float PlayTime)
{
	IActionRPGLoadingScreenModule& LoadingScreenModule = IActionRPGLoadingScreenModule::Get();
	LoadingScreenModule.StartInGameLoadingScreen(bPlayUntilStopped, PlayTime);
}

void URPGBlueprintLibrary::StopLoadingScreen()
{
	IActionRPGLoadingScreenModule& LoadingScreenModule = IActionRPGLoadingScreenModule::Get();
	LoadingScreenModule.StopInGameLoadingScreen();
}