UnityCsReference

Unity also has a C# wrapper layer around C++ objects. Most of the performant stuff is written in C++, and the C# source code they provide as reference is just a wrapper around it. For example, the Cloth bindings with annotations like [NativeHeader("Modules/Cloth/Cloth.h")] and [NativeClass("Unity::Cloth")]: https://github.com/Unity-Technologies/UnityCsReference/blob/...

The .NET source https://github.com/microsoft/referencesource https://github.com/microsoft/dotnet Unity reference source https://github.com/Unity-Technologies/UnityCsReference The above are example of production code. I use these as references all the time Awesome c# https://github.com/quozd/awesome-dotnet

The C# code is open for read access here: https://github.com/Unity-Technologies/UnityCsReference

it already is happening (kinda), they are modularizing their engine, and all the new parts are made open source biggest part what their graphics stack https://github.com/Unity-Technologies/Graphics (only the scripting part) competition is growing, unreal is fully open source, and more and more people have been asking for the source, there was even some drama few years ago when unity DMCA'd (if i remember correctly) a reference source code of unity engine (decompiled) on github, then unity made it officially available on their github: https://github.com/Unity-Technologies/UnityCsReference after users complained about it wich already proved effective and caused them to fix a huge performance issue shortly after: https://github.com/Unity-Technologies/UnityCsReference/pull/...

Unity render pipeline source is available here: https://github.com/Unity-Technologies/Graphics All the C# code running in the editor and runtimes is here: https://github.com/Unity-Technologies/UnityCsReference The code that interfaces directly with the platform API at the C++ level is restricted (you can get access but it's not really a viable option for a beginning graphics programmer :)). For many platforms the APIs themselves are proprietary and therefore that code cannot be shared easily. There's pretty good tooling support around graphics debugging: https://docs.unity3d.com/Manual/RenderDocIntegration.html https://docs.unity3d.com/Manual/FrameDebugger.html

This is correct, they released the source code a couple years ago under a reference license. https://blogs.unity3d.com/2018/03/26/releasing-the-unity-c-s... https://github.com/Unity-Technologies/UnityCsReference

They don't take pull requests, but Unity has at least had their source code published for reference for a while. https://github.com/Unity-Technologies/UnityCsReference

Yes. The tools source code is here: https://github.com/Unity-Technologies/UnityCsReference?files...

But unlike Unreal, the source code license is reference-only (yeah it sounds ridiculous, but you are not allowed to modify and recompile the source code.) Someone sent a pull request to the code (a bugfix which solved a lot of GC performance issues), only to get rejected because of the license (although it later got patched internally in Unity) https://github.com/Unity-Technologies/UnityCsReference/pull/...

They put up their editor source code on Github recently (https://github.com/Unity-Technologies/UnityCsReference), and originally it also included the full source to their runtime garbage collector, which ended up being the standard open source C++ boehm collector (https://github.com/ivmai/bdwgc) from the 90s. Unity should replace it with a reference counting object management system, or update to a newer garbage collection technique to minimize the inadvertent sweeps that cause huge choppy frame rate drops.

Important notes from article: This Friday we published the Unity engine and editor C# source code on GitHub, under a reference-only license. We are not releasing Unity as open source. Not even a little bit. (Sorry.) We also do not take pull requests against the C# reference source code. That’s it! The reference source code repository is at https://github.com/Unity-Technologies/UnityCsReference, enjoy using it as reference for your Unity learning needs.