Is it possible to accidentally sell the copyright to the code?

Question

Programming

On the Toaster, more than once they asked a question about the copyright to the code from which I realized that the authorship of the code === a literary copy. But today, for no reason at all, I thought about this - suppose I made a racing game on a self-written engine and sold it with all the giblets. The code is organized according to all the canons of the OOP, and to create the next game, I only need to replace the pictures.
And from here the question is - am I really violating the rights by creating a game based on oop?
That is, OOP teaches you how to create code for reuse, but then it turns out
that along with the game I sell my soul too?

Answer 1

It all depends on the sales contract.

Answer 2

You cannot "sell" your copyright. It is with you forever. But you most likely will not be able to use intellectual labor. It all depends on the contract. Most likely you will be asked to sign an NDA and an NCA (non-compete agreement) for a couple of years. And again, everything depends on the contract and on the initial conditions. If you work on commission, then 100% of you will require exclusive rights to the code forever. If you made a product and later decided to sell it, then there is already a certain room for maneuver and freedom of contract. You must clearly state that the name, appearance, etc. are transferred to the exclusive right, but the program code is not. It is clear that the price of such a transaction will be lower than the transfer of exclusive exclusive rights.