A while ago I posted a super simple 3D game engine that handled collision events with a player and a terrain. I have since revamped the code and added textures, assets, models, basic animations, super basic physics and a better camera system.
This engine is nowhere near as complex as other engines and is more or less experimental with a decent amount of bugs.
Now I must warn that this sketch is potentially NSFW. Nothing explicit, but rather the player model looks like a naked mannequin so I do advise checking it out in your own time to prevent weird looks.
Edit: may not work in Processing 3.5 due to PShape.rotateZ();
As always thanks for checking out my project