RicoTech is a 3D game engine written in C and OpenGL. I started it in April 2016 as a way to learn modern OpenGL’s programmable pipeline, and have been working on it on and off since then.
Here is the first ever screenshot of something being rendered:
the first bug:
and the first hard-coded scene:
You can browse the source code for RicoTech on GitHub.
Note: Most of the engine is not currently licensed for public use. Please contact me to inquire about licensing if you are interested in using the code for commercial or educational purposes.