There are tons of tools and instructions for making 3d models and animations in various software products. My question is: in video-game engines, when would you use a pre-rendered animation, and when would you use armature data in the model to manipulate your model in to the desired action?
Secondary questions: Are there any games that even use the model's rigging, in-game, or is everything pre-rendered?
Are there any human-readable file formats that contain armature data?
Lastly, from a OpenGL-level and up perspective, how would you implement a system for animating something like walking?
I am building an OpenGL graphics engine from scratch as a personal project, so if answers can cater to that context, it would be fantastic.