DocFX for Unity

DocFX usage example for Unity projects

DocFX tool generates a clean documentation that looks like the Unity documentation with a manual (written in Markdown) and a scripting API (from the C# scripts of the project).

This repository contains a simple Unity example project which documentation is automatically generated and deployed online: https://normanderwan.github.io/DocFxForUnity/. It references both C# API and Unity API.

DocFxForUnity documentation manual

DocFxForUnity documentation scripting API

Compatibility

Every combination below is built by the CI workflow on each change.

DocFX	Unity 6000.3 (6.3 LTS)	Unity 6000.6 (6.6)
2.60.0 (unsupported, see below)	✓
2.64.0	✓
2.77.0	✓
2.81.0	✓	✓

• Use DocFX 2.64 or later, with the .NET SDK 8.0 or later.
• Since DocFX 2.62, a C# compilation error stops the build. DocFX must therefore find the Unity managed DLLs, see Troubleshooting. DocFX 2.60 and 2.61 build without them with only warnings, and emit pages with no link to the Unity API.
• Unity 6000.3 is the version of this example project. The CI also builds against Unity 6000.6 with its own xref map, see Reference another Unity version.

Setup your documentation

1. Install the .NET SDK 8.0 or later, then DocFX:

   dotnet tool update -g docfx
   

2. Copy the Documentation/ folder to your Unity project:

     .
     ├── Assets
   + ├── Documentation
     ├── Package
     ├── ProjectSettings
     └── README.md
   

   You can rename Documentation/DocFxForUnity.csproj to match your project — just update the filename in Documentation/docfx.json under metadata[0].src[0].files accordingly.

3. Edit the following properties in Documentation/docfx.json, keep the others as it is:

     {
       "build": {
         "globalMetadata": // Edit your documentation website info, see: https://dotnet.github.io/docfx/reference/docfx-json-reference.html#predefined-metadata
         {
           "_appTitle": "Example Unity documentation",
           "_appFooter": "Example Unity documentation",
           "_enableSearch": true
         },
         "sitemap":
         {
           "baseUrl": "https://normanderwan.github.io/DocFxForUnity" // The URL of your documentation website
         }
     }
   

   It's the configuration file of your documentation. See https://dotnet.github.io/docfx/reference/docfx-json-reference.html for more details.

4. Edit Documentation/filterConfig.yml:

   apiRules:
   - include: # The namespaces to generate
       uidRegex: ^Your\.Namespace1
       type: Namespace
   - include:
       uidRegex: ^Your\.Namespace2
       type: Namespace
   - exclude:
       uidRegex: .* # Every other namespaces are ignored
       type: Namespace
   

   It tells DocFX which namespaces you want to generate the documentation. See https://dotnet.github.io/docfx/docs/dotnet-api-docs.html#filter-apis for more details.

5. Document your classes and methods. See https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/xmldoc/ for more details.

6. (Optional) Add your manual pages:

   • Write a Markdown file for each page in Documentation/manual/.
   • Keep a list of these pages on Documentation/manual/toc.yml.

7. (Optional) Add resources such as images:

   • Copy them to Documentation/resources/.
   • Reference them on your docs or manual pages.
   • See https://dotnet.github.io/docfx/docs/links-and-cross-references.html for more details.

8. (Optional) Document your namespaces:

   • For each namespace, add a Assets/Scripts/Your/Namespace1/Your.Namespace1.md file:

     ---
     uid: Your.Namespace1
     summary: Description of the Your.Namespace1 namespace.
     ---
     

   • See https://dotnet.github.io/docfx/tutorial/intro_overwrite_files.html to know how it works.

9. Generate your documentation:

   • On a command line opened on your project, run:

     cp README.md Documentation/index.md
     docfx Documentation/docfx.json --serve
     

   • The generated website will be visible at http://localhost:8080.

If you want to have a more similar look to the Unity documentation, see this UnityFX template for DocFX: https://github.com/code-beans/UnityFX.

Unity package layout

A Unity package has no Assets/ folder. To document one:

1. Copy the folder as Documentation~/ at the package root: Unity ignores folders whose name ends with ~.

2. In Documentation~/DocFxForUnity.csproj, point the sources to your package scripts:

   <Compile Include="../Runtime/**/*.cs" />
   

3. In Documentation~/docfx.json, point the namespace pages under build.overwrite[0].files to the same folder: "Runtime/**/*.md".

4. Use Documentation~/ instead of Documentation/ in the commands and CI files.

Generate automatically your documentation

If you're using GitHub:

1. Copy the .github/workflows/documentation.yml workflow to your Unity project:

     .
   + ├── .github
   + |   └── workflows
   + |       └── documentation.yml
     ├── Assets
     ├── Documentation
     ├── Package
     ├── ProjectSettings
     └── README.md
   

   The workflow builds every DocFX and Unity version of the Compatibility table. For your project, keep a single entry in jobs.build.strategy.matrix.include, with deploy: true and your Unity version. The Check Unity API links step reads _site/api/DocFxForUnity.Player.html: point it to one of your pages, or delete it.

2. Configure the Pages of your repository to use GitHub Actions.

3. Commit and push on the main branch: your documentation will be built and deployed to https://<username>.github.io/<repository>.

The workflow reads the Unity managed DLLs from the public game-ci editor Docker image unityci/editor:ubuntu-<unity version>-linux-il2cpp-3.2.2. Unity is never activated, so no license is needed.

If you're using GitLab, use the provided .gitlab-ci.yml. It runs in the same game-ci image. Set its image to your Unity version. Generated website is pushed to a public/ directory. See the GitLab Pages documentation for more details.

Troubleshooting / FAQ

• DocFX outputs: Warning:[ExtractMetadata]No project detected for extracting metadata.

  Solution: Make sure DocFxForUnity.csproj (or your renamed version) is inside the Documentation/ folder, and that the filename matches the entry in Documentation/docfx.json under metadata[0].src[0].files.

• DocFX outputs: Warning:[ExtractMetadata]No metadata is generated for Assembly-CSharp,Assembly-CSharp-Editor.

  Solution: Make sure you included your namespace in Documentation/filterConfig.yml:

  - include:
    uidRegex: ^Your\.Namespace1
    type: Namespace
  

• DocFX outputs error CS0246: The type or namespace name 'UnityEngine' could not be found, or MSBuild outputs Unity managed DLLs not found.

  This means DocFX could not locate Unity's managed DLLs. It looks in three places, in order:

  1. The UNITY_MANAGED_PATH environment variable (see below).
  2. lib/UnityEngine/ at the project root (populated automatically by the CI workflow).
  3. The default Unity Hub installation directory for your OS.

  If Unity Hub is installed at a non-default location, or you want to target a specific Unity version, set UNITY_MANAGED_PATH (see Advanced: UNITY_MANAGED_PATH below).

Reference another Unity version

The links to the Unity API come from the xref map of UnityXrefMaps. To link to the documentation of your Unity version, change this line on your docfx.json:

"xref": [ "https://normanderwan.github.io/UnityXrefMaps/<version>/xrefmap.yml" ],

where <version> is a Unity version in the form of YYYY.x (e.g. 2022.3, 6000.3, 6000.6).

Advanced: UNITY_MANAGED_PATH

By default, Documentation/DocFxForUnity.csproj auto-detects the Unity managed DLLs from the standard Unity Hub installation directory. Set UNITY_MANAGED_PATH when you need to:

• Use a Unity version installed at a non-default location.
• Pin to a specific version when multiple Unity versions are installed.
• Work without Unity Hub (standalone Unity install).

Point it to the UnityEngine subfolder inside your Unity installation's Managed directory:

OS	Example path
Windows	C:\Program Files\Unity\Hub\Editor\6000.3.26f1\Editor\Data\Managed\UnityEngine
macOS	/Applications/Unity/Hub/Editor/6000.3.26f1/Unity.app/Contents/Managed/UnityEngine
Linux	~/Unity/Hub/Editor/6000.3.26f1/Editor/Data/Managed/UnityEngine

Set it in your shell before running DocFX:

# macOS / Linux
export UNITY_MANAGED_PATH="/Applications/Unity/Hub/Editor/6000.3.26f1/Unity.app/Contents/Managed/UnityEngine"
docfx Documentation/docfx.json --serve

# Windows (PowerShell)
$env:UNITY_MANAGED_PATH = "C:\Program Files\Unity\Hub\Editor\6000.3.26f1\Editor\Data\Managed\UnityEngine"
docfx Documentation/docfx.json --serve

Disclaimer

This repository is not sponsored by or affiliated with Unity Technologies or its affiliates. “Unity” is a trademark or registered trademark of Unity Technologies or its affiliates in the U.S. and elsewhere.