What is a 3D engine and what happens in it?

Question

Game development

Started doing graphics: OpenGL. Rendering objects and animations in an application purely with OpenGL is not too difficult. I decided to start writing my own engine. Please explain and tell me the books that describe the structure of the engine and what it should do. As I understand it, the game engine is a wrapper over OpenGL.

Answer 1

Here is a very good tutorial on the subject. Because Judging by the post, you don't know OpenGL either.
But in general, without knowledge and experience of working with normal 3D engines, starting to write your own is like assembling your own computer (buying smd components, a board, poisoning it, soldering the whole thing, etc.), dreary and absolutely stupid.
PS take C++ and SFML and try to create your own 2D engine. It is many times easier and some experience will appear. And before writing a 3D engine directly, look at what Unity is and what it is eaten with. There are self-written 3D engines on the github, it would not hurt you to look at their code too. And then just take yours.

Answer 2

I decided to start writing my own engine
Decided to take up writing I don't know what. Well done.