UE5 用DLL文件制作第三方插件

本篇博文介绍了，如果在UE 中如何使用第三方库，及制作成插件的方法。
DLL 文件是上篇文章中创键的具体的方法见上篇文章。下面开始介绍方法
首先，创建一个空白的 UE5 C++ 项目，然后再创建一个空白内容的插件，如下图所示

修改UeWllApi.uplugin 里面的内容 如下图所示

在 插件的文件夹中 ，添加文件夹及DLL,LIB,.H 文件（注意具体的路径不要错否则可能插件制作不成功）如下图所示
首先在插件中添加一个ThridParty的文件夹（文件夹名字不要错）如下图所示

然后在ThridParty 内再添加一个文件夹（WllApi）如下图所示

然后在 WllApi 里面添加三个文件夹 bin,inc,lib(名字不要错)如下图所示

然后再bin ,lib，分别添加x64 文件夹 inc 里面添加WllApi 文件夹 如下图所示



然后再bin ,lib,的x64文件夹下添加 Debug,Release 文件夹，然后在Debug,Release 里面添加对应的Dll ,lib文件，在inc 里面的WllApi文件夹下添加需要的头文件.如下图所示

在 插件的的Build.cs （UeWllApi.Build.cs）中添加以下代码

// Copyright Epic Games, Inc. All Rights Reserved.
using System.IO;
using UnrealBuildTool;

public class UeWllApi : ModuleRules
{
	public UeWllApi(ReadOnlyTargetRules Target) : base(Target)
	{
		PCHUsage = ModuleRules.PCHUsageMode.UseExplicitOrSharedPCHs;
		
		PublicIncludePaths.AddRange(
			new string[] {
				// ... add public include paths required here ...
			}
			);
				
		
		PrivateIncludePaths.AddRange(
			new string[] {
				// ... add other private include paths required here ...
			}
			);
			
		
		PublicDependencyModuleNames.AddRange(
			new string[]
			{
				"Core",
				// ... add other public dependencies that you statically link with here ...
			}
			);
			
		
		PrivateDependencyModuleNames.AddRange(
			new string[]
			{
				"CoreUObject",
				"Engine",
				"Slate",
				"SlateCore",
				// ... add private dependencies that you statically link with here ...	
				 "Projects"
            }
			);
		
		
		DynamicallyLoadedModuleNames.AddRange(
			new string[]
			{
				// ... add any modules that your module loads dynamically here ...
			}
			);
		LoadPlugins(Target);
	}
	public void LoadPlugins(ReadOnlyTargetRules Target)
	{
		bool bSupport = false;
		string BinPath = "", LibPath = "";//初始化BIN,LIB路径为空
		string PluginPath = Path.Combine("ThridParty", "WllApi");
		PrivateIncludePaths.Add(Path.Combine(PluginDirectory,PluginPath,"inc"));
		if(Target.Platform==UnrealTargetPlatform.Win64)
		{
			if(Target.Configuration==UnrealTargetConfiguration.Debug)
			{
				BinPath = Path.Combine(PluginPath, "bin", "x64", "Debug");
				LibPath = Path.Combine(PluginPath, "lib", "x64", "Debug");
			}
            else
            {
				BinPath = Path.Combine(PluginPath, "bin", "x64", "Release");
				LibPath = Path.Combine(PluginPath, "lib", "x64", "Release");
            }
			bSupport = true;
        }
		if(bSupport)
		{
			PublicAdditionalLibraries.Add(Path.Combine(PluginDirectory, LibPath, "FirstDll.lib"));
			PublicDelayLoadDLLs.Add("FirstDll.dll");
			RuntimeDependencies.Add(Path.Combine("$(PluginDir)", BinPath, "FirstDll.dll"));
		}

	}
}

还有要注意添加 “Projects” 模块
具体结果如下图所示

在UeWllApi.h中添加以下代码，如下图所示

public :
	static constexpr wchar_t* ModuleName{ L"UeWllApi" };//插件的名字
public:

	/** IModuleInterface implementation */
	virtual void StartupModule() override;
	virtual void ShutdownModule() override;
public:
	static FName GetModularFeatureName()
	{
		static FName FeatureName = FName(ModuleName);
		return FeatureName;
	}
	static inline IModuleInterface& Get()
	{
		return FModuleManager::LoadModuleChecked<IModuleInterface>(ModuleName);
	}
	static inline bool IsAvailable()//是否可以获得
	{
		return FModuleManager::Get().IsModuleLoaded(ModuleName);
	}
private:
	FString GetLibaryPath();
	void* LibraryHandle = nullptr;

在UeWllApi.cpp中添加以下代码，如下图所示

#include "UeWllApi.h"
#include"Misc/MessageDialog.h"//消息框头文件
#include "Interfaces/IPluginManager.h"//插件管理头文件
#define LOCTEXT_NAMESPACE "FUeWllApiModule"

void FUeWllApiModule::StartupModule()
{
	FString LibraryPath = GetLibaryPath();
	LibraryHandle = LibraryPath.IsEmpty() ? nullptr : FPlatformProcess::GetDllHandle(*LibraryPath);//当前的路径是否为空，不为空的话获取句柄
	if (!LibraryHandle)
	{
		FMessageDialog::Open(EAppMsgType::Ok, LOCTEXT("ThridPartyLibraryError", "Failed to load WllApi Library"));
	}
}

void FUeWllApiModule::ShutdownModule()
{
	FPlatformProcess::FreeDllHandle(LibraryHandle);//释放句柄
	LibraryHandle = nullptr;
}
FString FUeWllApiModule::GetLibaryPath()
{
	FString BaseDir = IPluginManager::Get().FindPlugin(ModuleName)->GetBaseDir();//寻找插件
	FString LibraryPath;
#if PLATFORM_WINDOWS
# if PLATFORM_64BITS
# if UE_BUILD_DEBUG
	LibraryPath = FPaths::Combine(*BaseDir, TEXT("ThridParty/WllApi/bin/x64/Debug/FirstDll.dll"));
#	else
	LibraryPath = FPaths::Combine(*BaseDir, TEXT("ThridParty/WllApi/bin/x64/Release/FirstDll.dll"));
#   endif
#  else
#	if UE_BUILD_DEBUG
	LibraryPath = FPaths::Combine(*BaseDir, TEXT("ThridParty/WllApi/bin/x86/Debug/FirstDll.dll"));
#	else
	LibraryPath = FPaths::Combine(*BaseDir, TEXT("ThridParty/WllApi/bin/x86/Release/FirstDll.dll"));
#   endif
# endif
#endif
	return LibraryPath;

}
#undef LOCTEXT_NAMESPACE
	
IMPLEMENT_MODULE(FUeWllApiModule, UeWllApi)

添加C++类型的Blueprint Function Library，如下图所示，运行时是插件

在UeWllApiFunctionLibrary.h 添加以下代码，如下图所示

public:
	UFUNCTION(BlueprintCallable,Category="UeWllApi")
		static int GetSum();

在UeWllApiFunctionLibrary.cpp 添加以下代码 如图所示

int UUeWllApiFunctionLibrary::GetSum()
{
	return sum(3,4);
}

到此为止插件就制作完成了，只要打包调用就可以了，可以看到在本程序内可以调用结果也正确

打包出来，在其他程序调用也正确，结果如下图所示