I found a similar project that fits also your definition of "clone". The guy coded it in C++ and created a cross platform framework with render path for OpenGL

I found a similar project that fits also your definition of "clone". The guy coded it in C++ and created a cross platform framework with render path for OpenGL and DirectX. He even compiled it to JavaScript and WebGL via Emscripten. And it has some initial multiplayer support and he also wrote his own GUI framework. Interesting read: http://sea-of-memes.com/ http://sea-of-memes.com/