BACKGROUND
I have several hobby projects which contains quite a lot of code.
Most projects are just prototypes but it still contains the general idea of a game I want to code/make.
I'm a C++ programmer and have been in 4 projects that has been released to the wild before I went on a solo adventure (quit my job).

Recently though, I was thinking that I still need some funds. So I was thinking in the line of “I'll work on my hobbies at the same time as I work”.
But what I know of is that Game Making companies often times have contract such as “You cannot work on anything commercially that is on the same line of work as this company" (not exactly how they write but just example). And adding to that “We own all work you do” or something of those lines.

My projects are in Git privately, so I could show my Commit history if needed for anything (such as a lawsuit?? I don't know…)

THE QUESTION
So how do I protect my hobby projects even though it's not for commercial purposes, which I mean:
1. Company I work for cannot steal my code, even though it's coded in my free time.
2. Company cannot steal the idea I've shared (if I possibly show it in the interview or talk about it in work after I've gotten the job)

Do I need to ask for a special type of contract for this? Which I mean, ask for protection of my hobby projects?

Please redirect me to the correct forums if I did come to the wrong forums… I apologize if I did.

The company owns everything you did during the time you work for that company that was inspired or helped by the properties owned by that company or other people working for that company.

If you draw a comic while you work as a buildings architect for a construction company, there is not a problem.

If you make a game while you work for a game company, the company could take all that from you.

A good thing you can do, is to prove somehow that the idea you had about a game came to your mind before you started working for the company.

If you had an idea about a game while you worked for a game company, the company owns it. Period.
If you work for a pharmaceutic company and your work consists in discovering antibiotics, but you invent a pomade for hair loss in your free time, the company owns that pomade.

If you used the computers of the pharmaceutic company to design a game as a hobby, the company could try to grab it.

Basically, and resuming it, you need to prove that your hobby project in NO WAY POSSIBLE was helped by the company you work at.

If you move boxes for a gaming company, and you make a game as a hobby meanwhile, the company can grab it. You could have seen some concept of your game on the computers of the designers while moving boxes around and get inspired. The company can grab your hobby project.

If you work on a game for 5 years, then work in a game company for 6 months, then you leave that company and work one year more in that same old game and publish it, the company you worked for, can grab it. You need to prove it is an older idea/work.

Generally, remember that you should not use any kind of resources of the company for your hobby.
And remember, that courts are not about truth or justice. Courts are about who can call more witnesses. And of course, the one that has money to pay a salary to you will have more money than you in a court. So forget to win a case against your company based on your word vs the word of your company. You need solid proofs.

Find a way to prove your hobby project is older. For example, never ever delete or lose access to your private git. For the period you worked in the game company, you should not submit no code to your git, because you can not prove you did not use a computer of the company to work on that code.

It is all tricky. Most probably, if your hobby game makes no money at all, and has not the potential to make no money never, your company would not spend money on lawyers to grab it. If you use the models of the game company, even if you are not making money of it, it is bad. They can go for you.

Resuming it a third time - prove that in no way possible, not even in the slightest, your hobby project was helped by all the kind of resources a company could have been giving you.

And read what you sign.

You're spreading piffle, @nikito , don't do that.

In some countries it is not allowed for people outside of legal subjects to give legal advice.

@zansin , have a word with a lawyer in your country, one who's specialized in these things. Explain your questions to them and your concerns, then they can explain your rights and the legal possibilities you have, fitted to your case.

@Green_Baron It is super normal people to ask things on internet.

The same way we could answer to anybody who asks something here “find a programmer and ask him”. But we don't do that.

People ask on internet. It is normal. He wants an orientation. Before spending depending of the country he lives in up to 500$ for a lawyer to be told the same.

And I am not inventing things either.

These people are likely to be fobbed off with low quality content that isn't helpful at all.

I would not hire a person who wants to work in the same field in his free time.
What if he is designing the story of the game for me. Then he has an idea and decides that it is too cool to give it to me “for the salary i give him”, he will keep it for himself and keep thinking about a less awesome game story for me. What if he decides the idea is worth a book, instead giving it to me?
If i pay to somebody i need his complete dedication.
And when we are talking about creativity, muse and ideas can come when one wakes up in the morning or when he is having a dinner outside in a Sunday night. And i want that idea for me.
A designer creates a great design for a fox-girl. Then he decides it is too cool for the salary i pay him and saves it for his own portfolio and starts creating another fox-girl design for me.
If you hunted a bug at work 8 hours in Monday, but did not find it, then you travel in the bus back home outside working hours and suddenly you solve it. Who owns it? It is about your work but happened outside working hours.
It is easier and makes more sense for me, to block the hobbies of the people i hire. In case these hobbies are in the same area.
If the area is not related, i am fine with people having their hobbies.

Harvard -

@Green_Baron So much “piffle” in this thread. Time for you to load another round in your gun.

Bregma said:
What it comes down to is make terms clear in your employment contract

Many of these contracts are written in a hard to understand language.
If i try to imagine it in practice - i stand in the office of the employer, not hired yet, waiting for the approval of the job position. Asking lot of questions about the contract. Employer and his secretary start to get nervous, i start to sweat. I ask them to call their lawyer to come over only for me. It all becomes tense. After a whole hour of negotiations, they just give up on my job application. I am imagining it practically now in front of my eyes, and it could work or not.

In theory you can ask your wife for an explication where she was the whole night.
In practice she could shout at you: “If you don't trust me, our relationship can not work.”, and no answer.

@zansin Personally, i would serve food in McDonalds and keep working on my hobby. Working for a company is exigent. In any case, you will need to make your brain work in another direction, or in the same but it is clash of interests. A job as a night guard is not requiring your brain to work hard. You can think about your project while staring at the monitors. Your mind will be burning calories only for your project.
Imagine you debug a data base on work and then have to come back home and switch back to your game. It takes time to switch and you are mentally wasted.