[UE4]Build.cs Notes

Keywords: UE4, Build.cs

How to get the current project directory

New way

using System.IO;
using UnrealBuildTool;  

public class MyProject : ModuleRules  
{
    private string ProjectRoot
    {
        get { return Path.GetFullPath(Path.Combine(ModuleDirectory, "../../")); }
    }

    private string ThirdPartyPath
    { 
        get { return Path.GetFullPath(Path.Combine(ModuleDirectory, ProjectRoot, "ThirdParty")); }
    }

    public MyProject(ReadOnlyTargetRules Target) : base(Target)
    {  
    }  
}

Reference:
https://answers.unrealengine.com/questions/237166/how-can-i-get-the-current-project-path-within-the.html

Old way (Removed in 4.21)

using System.IO;  
using UnrealBuildTool;  

public class MyProject : ModuleRules  
{  
    RulesAssembly r;  

    private string ModulePath  
    {  
        get { return Path.GetDirectoryName( r.GetModuleFileName(this.GetType().Name).CanonicalName); }  
    }  

    private string ThirdPartyPath  
    {  
        get { return Path.GetFullPath(Path.Combine(ModulePath, "../../ThirdParty/")); }  
    }  

    public MyProject(TargetInfo Target)  
    {  
        FileReference CheckProjectFile;  
        UProjectInfo.TryGetProjectForTarget("MyProject", out CheckProjectFile);  
        r = RulesCompiler.CreateProjectRulesAssembly(CheckProjectFile);  
    }
}

How to include third party libraries

Example:

using UnrealBuildTool;
using System.IO;

public class TestTD : ModuleRules
{
    private string ProjectRoot
    {
        get { return Path.GetFullPath(Path.Combine(ModuleDirectory, "../../")); }
    }

    private string ThirdPartyPath
    { 
        get { return Path.GetFullPath(Path.Combine(ModuleDirectory, ProjectRoot, "ThirdParty")); }
    }

    public TestTD(ReadOnlyTargetRules Target) : base(Target)
    {
        PCHUsage = PCHUsageMode.UseExplicitOrSharedPCHs;

        PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore", "HeadMountedDisplay", "NavigationSystem", "AIModule" });

        LoadOpenCV(Target);
    }

    public bool LoadOpenCV(ReadOnlyTargetRules Target)
    {    
        // Start OpenCV linking here!
        bool isLibrarySupported = false;

        //Library path
        string PlatformString = null;
        string libSuffix = null;
        switch (Target.Platform)
        {
            case UnrealTargetPlatform.Win64:
            {
                PlatformString = "Win64";
                libSuffix = ".lib";
                break;
            }
            case UnrealTargetPlatform.Android:
            {
                PlatformString = "Android";
                libSuffix = ".a";
                break;
            }
        }

        bool isdebug = Target.Configuration == UnrealTargetConfiguration.Debug;
        string DebugLibNameFlag = "";
        if(isdebug)
        {
            DebugLibNameFlag = "d";
        }

        if (null != PlatformString)
        {
            //LibrariesPath value for Windows in Debug: D:\MyProj\ThirdParty\OpenCV\Libraries\Win64\opencv_world348d.lib
            string LibrariesPath = Path.Combine(ThirdPartyPath, "OpenCV", "Libraries", PlatformString, "opencv_world348" + DebugLibNameFlag + libSuffix);
            PublicAdditionalLibraries.Add(LibrariesPath);

            System.Console.WriteLine("++++++++++++ Set OpenCV Libraries: " + LibrariesPath + "\r");
        }

        //Include path
        string IncludePath = Path.Combine(ThirdPartyPath, "OpenCV", "Includes");
        PublicIncludePaths.Add(IncludePath);

        System.Console.WriteLine("++++++++++++ Set OpenCV Includes: " + IncludePath + "\r");

        PublicDefinitions.Add(string.Format("WITH_OPENCV_BINDING={0}", isLibrarySupported ? 1 : 0));

        return isLibrarySupported;
    }
}

If want to include a number of libraries, you can do like this:

// Add static library search path 
PublicLibraryPaths.Add(LibPath);

PublicAdditionalLibraries.Add("opencv_calib3d340.lib");
PublicAdditionalLibraries.Add("opencv_core340.lib");
PublicAdditionalLibraries.Add("opencv_cudaarithm340.lib");
PublicAdditionalLibraries.Add("opencv_cudabgsegm340.lib");

// Add shared library search path
PublicRuntimeLibraryPaths.Add(DllPath);

PublicDelayLoadDLLs.Add("opencv_calib3d340.dll");
PublicDelayLoadDLLs.Add("opencv_core340.dll");
PublicDelayLoadDLLs.Add("opencv_cudaarithm340.dll");
PublicDelayLoadDLLs.Add("opencv_cudabgsegm340.dll");

Reference:
[UE4]UnrealBuildTool APIs in common
https://dawnarc.com/2019/07/ue4unrealbuildtool-apis-in-common/

PublicLibraryPaths was renamed to PublicSystemLibraryPaths in v4.24.

How to disable compilication warning upon third party headers included

Example:

THIRD_PARTY_INCLUDES_START
#include "libwebsockets.h"
THIRD_PARTY_INCLUDES_END

How to shadow macros on Windows that are the same name as Unreal?

Example:

#include "Windows/AllowWindowsPlatformTypes.h"
#include <windows.h>
#include "Windows/HideWindowsPlatformTypes.h"

How to get Visual Studio Compiler Version

public class WebRTC : ModuleRules
{
    public WebRTC(ReadOnlyTargetRules Target) : base(Target)
    {
        //2019 or 2015, and so on.
        string VS_Version = Target.WindowsPlatform.GetVisualStudioCompilerVersionName();
    }
}

Macros on building mode

Engine\Source\Runtime\Core\Public\Misc\Build.h

/*--------------------------------------------------------------------------------
Build configuration coming from UBT, do not modify
--------------------------------------------------------------------------------*/

// Set any configuration not defined by UBT to zero
#ifndef UE_BUILD_DEBUG
    #define UE_BUILD_DEBUG                0
#endif
#ifndef UE_BUILD_DEVELOPMENT
    #define UE_BUILD_DEVELOPMENT        0
#endif
#ifndef UE_BUILD_TEST
    #define UE_BUILD_TEST                0
#endif
#ifndef UE_BUILD_SHIPPING
    #define UE_BUILD_SHIPPING            0
#endif
#ifndef UE_GAME
    #define UE_GAME                        0
#endif
#ifndef UE_EDITOR
    #define UE_EDITOR                    0
#endif
#ifndef UE_BUILD_SHIPPING_WITH_EDITOR
    #define UE_BUILD_SHIPPING_WITH_EDITOR 0
#endif
#ifndef UE_BUILD_DOCS
    #define UE_BUILD_DOCS                0
#endif

How to add macro in build.cs

1st way
Build.cs:

PublicDefinitions.Add("TEST");

C++:

#ifdef TEST
    //other code
#endif

2nd way
Build.cs:

PublicDefinitions.Add("TEST=1");

C++:

#if TEST
    //other code
#endif

using GlobalDefinitions.Add("TEST=1"); in Target.cs if want to give a global macro.

How to disable code optimization

public class MyProj : ModuleRules
{
    public MyProj(ReadOnlyTargetRules Target) : base(Target)
    {
        OptimizeCode = CodeOptimization.InNonDebugBuilds;
    }
}

How to disable function inline in certain modules

public class MyProjTarget : TargetRules
{
    public MyProjTarget(TargetInfo Target) : base(Target)
    {
        if (Configuration == UnrealTargetConfiguration.Debug || Configuration == UnrealTargetConfiguration.DebugGame)
        {
            bUseInlining = false;
        }
    }
}

How to disable function inline and code optimization for whole project

Add follows in function AppendCLArguments_Global in VCToolChain.cs (Engine\Source\Programs\UnrealBuildTool\Platform\Windows\VCToolChain.cs):

if (Target.Configuration != UnrealTargetConfiguration.Shipping)
{
    CompileEnvironment.bUseInlining = false;
    CompileEnvironment.bOptimizeCode = false;
}

Check if target type is editor, or client, or server

if (Target.Type != TargetType.Server)
{
    PrivateDependencyModuleNames.AddRange(new string[]
    {
        "Imgui"
    });
}

Other ways:

if (Target.Type == TargetType.Editor)
{
    PrivateDependencyModuleNames.AddRange(new string[] { "UnrealEd" });
}

if (Target.bBuildEditor)
{
    PrivateDependencyModuleNames.AddRange(new string[] { "UnrealEd" });
}

How to copy files (dll) on building

if (!Directory.Exists(binariesDir))
    Directory.CreateDirectory(binariesDir);

if (!File.Exists(Path.Combine(binariesDir, filename)))
    File.Copy(Filepath, Path.Combine(binariesDir, filename), true);

Reference:
https://forums.unrealengine.com/t/how-to-modify-build-file-to-copy-dlls-to-binaries/353587/2

How to get project directory in Target.cs.

MyGame.Target.cs:

string ProjDir = ProjectFile.FullName.Replace("MyGame.uproject", "");

How to enable C++17 features in UE4

MyProj.Build.cs:

CppStandard = CppStandardVersion.Cpp17;

Or modify \Engine\Source\Programs\UnrealBuildTool\Platform\Windows\VCToolChain.cs:
Add follows in function void AppendCLArguments_CPP(CppCompileEnvironment CompileEnvironment, List<string> Arguments),

Arguments.Add("/std:c++17");

Origin:
https://gamedev.stackexchange.com/a/184027/117871 https://gist.github.com/bw2012/069bcb43d0983217dc36f782fc2f1bcc

我年轻时，听一位教授讲：“人生都只有一个想法，终其一生不过是不断丰富它。”我当时觉得：“一辈子只围绕一个念头转？这未免也太反动了！”五十岁时，我明白他是对的：我这一辈子都在追随一个想法，问题是我从来都不知道是哪个。──翁贝托·埃科《密涅瓦火柴盒》

[UE4]Build.cs Notes

How to get the current project directory

How to include third party libraries

How to disable compilication warning upon third party headers included

How to shadow macros on Windows that are the same name as Unreal?

How to get Visual Studio Compiler Version

Macros on building mode

How to add macro in build.cs

How to disable code optimization

How to disable function inline in certain modules

How to disable function inline and code optimization for whole project

Check if target type is editor, or client, or server

How to copy files (dll) on building

How to get project directory in Target.cs.

How to enable C++17 features in UE4

Wang Aiguo