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

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/master/Modules/Cloth/Cloth.bindings.cs https://github.com/Unity-Technologies/UnityCsReference/blob/...