以UE5第三方插件库为基础，编写自己的第三方库插件，并且能够在运行时复制.dll

首先，创建一个空白的C++ 项目，创建第三方插件库。如下图所示
在这里插入图片描述
编译自己的.Dll 和.lib 库，打开.sln 如下图

ExampleLibrary.h 的代码如下

#if defined _WIN32 || defined _WIN64
#define EXAMPLELIBRARY_IMPORT __declspec(dllimport)
#elif defined __linux__
#define EXAMPLELIBRARY_IMPORT __attribute__((visibility("default")))
#else
#define EXAMPLELIBRARY_IMPORT
#endifEXAMPLELIBRARY_IMPORT void ExampleLibraryFunction();
EXAMPLELIBRARY_IMPORT int AddNumbersFunction(int a,int b);

ExampleLibrary.cpp 的代码如下

#if defined _WIN32 || defined _WIN64#include <Windows.h>#define EXAMPLELIBRARY_EXPORT __declspec(dllexport)
#else#include <stdio.h>
#include "ExampleLibrary.h"
#endif#ifndef EXAMPLELIBRARY_EXPORT#define EXAMPLELIBRARY_EXPORT
#endifEXAMPLELIBRARY_EXPORT void ExampleLibraryFunction()
{
#if defined _WIN32 || defined _WIN64MessageBox(NULL, TEXT("Loaded ExampleLibrary.dll from Third Party Plugin sample."), TEXT("Third Party Plugin"), MB_OK);
#elseprintf("Loaded ExampleLibrary from Third Party Plugin sample");
#endif
}EXAMPLELIBRARY_EXPORT int AddNumbersFunction(int a,int b)
{return a+b;
}

然后编译.Dll 库，配置如下
在这里插入图片描述
然后点击生成解决方案，编译成功后，如下图所示

创建蓝图库函数，运行时放在插件中，如下图所示

要在WlThirdPartyLibrary.Build.cs 添加 “Engine”,“CoreUObject”，否则编译不成功
如下图

在蓝图库函数里面调用.Dll 里面得函MyBlueprintFunctionLibrary.h的代码如下

// Fill out your copyright notice in the Description page of Project Settings.#pragma once#include "CoreMinimal.h"
#include "Kismet/BlueprintFunctionLibrary.h"
#include "MyBlueprintFunctionLibrary.generated.h"/*** */
UCLASS()
class WLTHIRDPARTYLIBRARY_API UMyBlueprintFunctionLibrary : public UBlueprintFunctionLibrary
{GENERATED_BODY()
public:UFUNCTION(BlueprintCallable,Category="Function")static int AddNumbers(int a, int b);
};

MyBlueprintFunctionLibrary.cpp 的代码如下

// Fill out your copyright notice in the Description page of Project Settings.#include "MyBlueprintFunctionLibrary.h"
#include "WlThirdPartyLibraryLibrary/ExampleLibrary.h"
int UMyBlueprintFunctionLibrary::AddNumbers(int a, int b)
{return AddNumbersFunction(a, b);
}

WlThirdPartyLibraryLibrary.Build.cs 的代码修改比较大，添加了自动复制.dll 的功能，代码如下

// Fill out your copyright notice in the Description page of Project Settings.using System.IO;
using UnrealBuildTool;public class WlThirdPartyLibraryLibrary : ModuleRules
{public WlThirdPartyLibraryLibrary(ReadOnlyTargetRules Target) : base(Target){Type = ModuleType.External;PublicSystemIncludePaths.Add("$(ModuleDir)/Public");if (Target.Platform == UnrealTargetPlatform.Win64){// Add the import libraryPublicAdditionalLibraries.Add(Path.Combine(ModuleDirectory, "x64", "Release", "ExampleLibrary.lib"));// Delay-load the DLL, so we can load it from the right place firstPublicDelayLoadDLLs.Add("ExampleLibrary.dll");// Ensure that the DLL is staged along with the executableCopyDll(Path.Combine(ModuleDirectory, "x64", "Release", "ExampleLibrary.dll"));}else if (Target.Platform == UnrealTargetPlatform.Mac){PublicDelayLoadDLLs.Add(Path.Combine(ModuleDirectory, "Mac", "Release", "libExampleLibrary.dylib"));RuntimeDependencies.Add("$(PluginDir)/Source/ThirdParty/WlThirdPartyLibraryLibrary/Mac/Release/libExampleLibrary.dylib");}else if (Target.Platform == UnrealTargetPlatform.Linux){string ExampleSoPath = Path.Combine("$(PluginDir)", "Binaries", "ThirdParty", "WlThirdPartyLibraryLibrary", "Linux", "x86_64-unknown-linux-gnu", "libExampleLibrary.so");PublicAdditionalLibraries.Add(ExampleSoPath);PublicDelayLoadDLLs.Add(ExampleSoPath);RuntimeDependencies.Add(ExampleSoPath);}}private void CopyDll(string InFilePath){// string TargetDirectory = Path.GetFullPath(Path.Combine(PluginDirectory, "Binaries/ThirdParty", "WlThirdPartyLibraryLibrary", "Win64"));string TargetDirectory = Path.GetFullPath(Path.Combine(PluginDirectory, "Binaries/ThirdParty/WlThirdPartyLibraryLibrary/Win64"));//目标文件夹的路径string FileName = Path.GetFileName(InFilePath);//获得文件名字// Ensure that the DLL is staged along with the executableif (!Directory.Exists(TargetDirectory))//检查目标文件夹是否存在不存在则创建{Directory.CreateDirectory(TargetDirectory);}string TargetFilePath = Path.Combine(TargetDirectory, FileName);//目标文件的路径if (!File.Exists(TargetFilePath)){File.Copy(InFilePath, TargetFilePath, true);//复制.dll}RuntimeDependencies.Add("$(PluginDir)/Binaries/ThirdParty/WlThirdPartyLibraryLibrary/Win64/ExampleLibrary.dll");//运行时添加DLL}
}

还有最后一步，添加白名单WlThirdPartyLibrary.uplugin 的代码如下

{"FileVersion": 3,"Version": 1,"VersionName": "1.0","FriendlyName": "WlThirdPartyLibrary","Description": "","Category": "Other","CreatedBy": "","CreatedByURL": "","DocsURL": "","MarketplaceURL": "","SupportURL": "","CanContainContent": true,"IsBetaVersion": false,"IsExperimentalVersion": false,"Installed": false,"Modules": [{"Name": "WlThirdPartyLibrary","Type": "Runtime","LoadingPhase": "Default","WhitelistPlatforms": ["Win64"]}]
}