I would like to share with you my work on one external renderer, called BGFX. BGFX basically supports lots of different (modern) rendering systems such as Vulkan, OpenGL 3.0+, OpenGL ES, etc.
The renderer is currently as part of my Open-Source game (SpaceGolfGame). After I finish it, I plan on moving it to separate repository. Also please note, it is just a part of a game, so basically all I implemented was minimal functionality to make my game work.
You can browse the code here for now: https://github.com/charlieamer/SpaceGolfGame/tree/master/SpaceGolfGame/SpaceGolfGame/Gui
If you want to compile the code, you'll have to manually include .cpp files. You'll also need external shader files for rendering (I am working on making this redundant). You'll also need to include bgfx_utils.cpp from BGFX repository (which can be found in examples). There will be more info in the repository itself, so check out the link.
I know it is a lot of work just to get started, but if you need it, and you think it is worth it, feel free to try it, help me continue development and make pull requests.
Have fun, hope you like it
