at3 has been discontinued and replaced by the campy project, which continues work in the same direction but is currently private.
This was a C++/OpenGL/Vulkan sandbox that I use to build my graphics and AI-related projects. I'm in the process of making it fit for public consumption, or in other words, it's not currently fun to read or well documented for a newcomer. Among the branches you can find some of the projects listed on my website.