## 安装homebrew
参考：
- https://www.jianshu.com/p/e0471aa6672d

国内镜像安装命令：
```c++
/bin/bash -c "$(curl -fsSL https://gitee.com/ineo6/homebrew-install/raw/master/install.sh)"
```

安装完之后需要替换源：
### 1.必备设置
-   替换 brew.git：
```bash
git -C "$(brew --repo)" remote set-url origin https://mirrors.ustc.edu.cn/brew.git
```
-   替换 homebrew-core.git：
```bash
git -C "$(brew --repo homebrew/core)" remote set-url origin https://mirrors.ustc.edu.cn/homebrew-core.git
```
### 2.按需设置
-   替换 homebrew-cask.git：
```bash
git -C "$(brew --repo homebrew/cask)" remote set-url origin https://mirrors.ustc.edu.cn/homebrew-cask.git
```
-   替换homebrew-bottles：
首先要先区分你的mac用哪种终端工具，如果是 bash，则执行：
```bash
echo 'export HOMEBREW_BOTTLE_DOMAIN=https://mirrors.ustc.edu.cn/homebrew-bottles' >> ~/.bash_profile
source ~/.bash_profile
```
若是 zsh，则执行：
```bash
echo 'export HOMEBREW_BOTTLE_DOMAIN=https://mirrors.ustc.edu.cn/homebrew-bottles' >> ~/.zshrc
source ~/.zshrc
```


## macOS开发环境
https://ue5wiki.com/wiki/2329190d/

运行生成解决方案.sh时会提示：
>ERROR: Invalid SDK MacOSX.sdk, not found in /Library/Developer/CommandLineTools/Platforms/MacOSX.platform/Developer/SDKs

确认安装Xcode之后执行
```bash
sudo ln -s /Applications/Xcode.app/Contents/Developer/Platforms /Library/Developer/CommandLineTools/Platforms
```

## 为 xcode 开启多线程编译
AMD CPU信息查看APP：
https://github.com/trulyspinach/SMCAMDProcessor/releases/tag/0.7.1

首先看一下 Mac 的硬件配置：
>sysctl machdep.cpu

找到 `machdep.cpu.core_count` 字段，其中的数值就是 Mac 的核心数。然后可以给 xcode 开启多线程，数量数为核心数 *2，如我的是 8 核，就可以开启 16 线程：
> defaults write com.apple.Xcode PBXNumberOfParallelBuildSubtasks 16

# 编译流程
- 先编译ShaderCompileWork
- 后编译UE5

## ATOMIC_VAR_INIT错误
https://forums.unrealengine.com/t/cannot-build-ue-5-1-1-from-source-on-macos-ventura-13-3-1-xcode-14-3/885545
macOS 13.4 Xcode 14.3编译UE5.1会报错，其原因是：
>So it seems the error is related to the deprecation of `ATOMIC_VAR_INIT` [since C++20 2](https://en.cppreference.com/w/cpp/atomic/ATOMIC_VAR_INIT). I gather [from this table 3](https://en.wikipedia.org/wiki/Xcode#Xcode_11.0_-_14.x_(since_SwiftUI_framework)_2) that Xcode 14.3 includes a clang patch version bump from 14.0.0 to 14.0.3, and a llvm major version bump from 14.0.0 to 15.0.0. With my limited understanding of clang and llvm, I would guess that llvm 15 compiles at C++20, and therefore throws the build error, whereas the build is successful with Xcode 14.2.

解决方法是：
- ShaderCompileWorker.target.cs添加下面的代码。
- UnrealEditor.Target.cs添加下面的代码（去掉bOverrideBuildEnvironment那一行）。

```c++
using UnrealBuildTool;
using System.Collections.Generic;

public class YourGameTarget : TargetRules
{
	public YourGameTarget(TargetInfo Target) : base(Target)
	{
        if(Target.Platform == UnrealTargetPlatform.Mac)
        {
            bOverrideBuildEnvironment = true;
            AdditionalCompilerArguments = "-Wno-deprecated-pragma";  // you can add more separated with spaces here
        }

      ...
	}
}
```

我对文件做了一些修改`Engine/Source/Programs/UnrealBuildTool/Platform/Mac/MacToolChain.cs`，错误消失了。
```c++
if (CompilerVersionGreaterOrEqual(14, 0, 0)) 
{ 
	Arguments.Add("-Wno-deprecated-pragma"); 
}
```

功能齐全：
```csharp
protected override void GetCompileArguments_Global(CppCompileEnvironment CompileEnvironment, List<string> Arguments)
{
	base.GetCompileArguments_Global(CompileEnvironment, Arguments);

	Arguments.Add("-fasm-blocks");

	if (CompileEnvironment.bEnableOSX109Support)
	{
		Arguments.Add("-faligned-new"); // aligned operator new is supported only on macOS 10.14 and above
	}

	// Pass through architecture and OS info
	Arguments.Add("" + FormatArchitectureArg(CompileEnvironment.Architecture));
	Arguments.Add($"-isysroot \"{SDKPath}\"");
	Arguments.Add("-mmacosx-version-min=" + (CompileEnvironment.bEnableOSX109Support ? "10.9" : Settings.MacOSVersion));

	List<string> FrameworksSearchPaths = new List<string>();
	foreach (UEBuildFramework Framework in CompileEnvironment.AdditionalFrameworks)
	{
		FileReference FrameworkPath = new FileReference(Path.GetFullPath(Framework.Name));
		if (!FrameworksSearchPaths.Contains(FrameworkPath.Directory.FullName))
		{
			Arguments.Add($"-F \"{NormalizeCommandLinePath(FrameworkPath.Directory)}\"");
			FrameworksSearchPaths.Add(FrameworkPath.Directory.FullName);
		}
	}

	
	if (CompilerVersionGreaterOrEqual(14, 0, 0))
	{
		Arguments.Add("-Wno-deprecated-pragma");
	}
}
```