I am a game developer now (sorta)
I mean very technically speaking: I have written a computer program which is also a game.
-- Is it chess...?
-- Yes, it is chess :/
But it is technically a game, and I have developed it! OK, I have coded it, development implies making up some rules I guess, but I came up with the colors for the tiles!
BEHOLD:

What fancy features it has? Thanks for asking!
- You can move, but only legal moves and only if it's your turn!
- Check is enforced, so you cannot just make a random move if you are in check, or you cannot check yourself by revealing your king.
- Mate is also detected (no legal moves left)
- En-fucking-passant also functions, it was an absolute nightmare.
- Castling also functions.
What features I will add?
- Promoting... and that's it, I have a prototype UI for it, I just need to add the logic

I wanted to add a basic computer logic too with minimax, but my code structure quickly spiraled into absolute chaos, so I don't really feel like duct taping anything else to it.
What drives me crazy is that this is the second version, I started over once because the spaghetti code was unbearable. And now I ended up with a different flavor of spaghetti. Mamma mia!
I tried to apply some best practices and add comments like a pr0 h4x0r, but reading them a week later reveals more about my mental state than the code itself:

What did I learn during the process?
- Using arrays won't make you an old school hardcore programmer, so just leave them unless you have a good reason to use them over an std::vector
- Pawns are the most complex piece in the whole game, they can do like 5 things
- A king is like a queen but breaking out of a for-loop early
- Promising to keep the input, the rendering and the game logic separated is a promise likely to be broken
- SDL2 is not really more difficult than SFML, you barely have to touch the whole C-part, once your texture is loaded it is business as usual
Hurrdurr BuT You ArE Not ActuaLly a GamE dEvelopeR UnLesS iT's youR JoB or PubLished a gamE arfhhdd
It is alright, let it out of your system.