unity-technologies/unitycsreference

★ 12,831C#Audience · developerComplexity · 1/5LicenseSetup · easy

Mindmap

mindmap
  root((Unity C# Reference))
    What it is
      Read-only source
      Engine internals
      Editor source code
    How to use it
      Browse API internals
      Debug engine behavior
      Study editor patterns
    Limitations
      No modification allowed
      No redistribution
      No pull requests
    Audience
      Unity developers
      Plugin authors
      Tool creators

mindmap root((Unity C# Reference)) What it is Read-only source Engine internals Editor source code How to use it Browse API internals Debug engine behavior Study editor patterns Limitations No modification allowed No redistribution No pull requests Audience Unity developers Plugin authors Tool creators

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Things people build with this

USE CASE 1

Browse Unity's internal C# implementation to understand exactly how a built-in API method works under the hood.

USE CASE 2

Debug unexpected Unity engine behavior by tracing the source code of the specific system causing the issue.

USE CASE 3

Study how Unity's editor windows are implemented to write better custom editor tools for your game project.

USE CASE 4

Find the root cause of a Unity bug before submitting a detailed report through Unity's official bug reporter.

Tech stack

Getting it running

Difficulty · easy Time to first run · 5min

No installation needed, this is a read-only browsable reference, not a runnable project.

Read-only reference only, you may not modify, copy, or redistribute this code in any form without a separate commercial source license from Unity Technologies.

In plain English

This repository contains the C# source code for the Unity game engine and its editor, published by Unity Technologies for reference purposes only. Unity is one of the most widely used game development platforms, and this repository gives developers the ability to read through the actual C# code that powers the engine's internal systems and the editor tools. The key restriction is that this is a read-only reference, not an open-source release. The license explicitly does not allow modifying or redistributing the code in any form, source or binary. If you want a license to actually modify Unity's source code, including the C++ portions, you need to contact Unity's sales team for a commercial source code agreement. Because of this read-only nature, the repository does not accept pull requests. If you find something that looks like a bug, the README directs you to file it through Unity's built-in bug reporter rather than GitHub. A link to a Unity blog post explaining the reasoning behind this release model is included in the README. The published code corresponds to specific Unity versions, and the file and folder layout matches the internal Unity source tree, which can change between versions. The README notes that updates beyond version 6.2.0b4 are currently paused while internal validation processes at Unity are completed, with a plan to resume updates at a later date. The repository is useful for Unity developers who want to understand how built-in Unity APIs actually work, read the implementation of editor windows, or trace through the source when debugging unexpected engine behavior. Third-party code included in the repository is subject to separate notices documented in the repository.

Copy-paste prompts

Prompt 1

I am reading the Unity C# Reference source. Help me find where the Physics.Raycast method is implemented and explain what edge cases the internal code handles.

Prompt 2

Using the Unity C# Reference, explain how the GameObject.Find method searches the scene hierarchy internally so I understand why it is slow for large scenes.

Prompt 3

I am looking at the Unity C# Reference Editor source. Explain how custom property drawers are registered and rendered in the Inspector window.

Prompt 4

Help me trace through the Unity C# Reference to understand how SerializedObject and SerializedProperty work when editing component values in the Inspector.

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