Since i learned and used SDL to make a game last months, I've been trying to develop a game engine using what I've learned. I thought about mixing SDL and Qt for doing that. Qt will handle the GUI part and SDL the core of the engine. So since I'm an amateur and it's my first time mixing two libraraires, I thought I can use some advice. On of my questions is this : Do I combine the two libraries or not ? I mean for example, when using the game engine, after finishing, the game engine will generate an SDL code that will be compiled externally and launched . Is that a code idea ?

I mean for example, when using the game engine, after finishing, the game engine will generate an SDL code that will be compiled externally and launched

No it wont. It will generate the SDL library and however link that together with QT in another library but if not compiling as static libs you will still have all 3 libraries you need to ship. SDL, QT and your stick-them-all-together one

Mixing two libraries dosent make a game engine it is just .. well .. mixing two libraries together. Creating a game engine isnt something someone could do by simply taking two free libraries and bound them together and put a sticker or logo on it. If so you would not pay thousands of dollars for AAA Engine licenses and beleive me, someone would have combined SDL and QT before you were thought of to do.

Creating a game engine is in first place thinking of what do you need and what does SDL and QT carrie arround with them.

- How about Assets, do you have an Asset Manager?

- What kind of data types could it handle?

- Do you have Shaders?

- What about Animations, how do you handle that?

- Filesystem?

- Input Handling?

- Physics?

- How is your render pipeline set up, Lightning, Shadows?

- Mesh handling?

- Terrain handling?

- How do you build up scenes?

- Profiling?

- Networking?

And you are up to here not even reaching the point of gameplay but still crawling inside the basics of what an engine has under the hood. Sure you could find a free library out there for every aspect of a game engine but at the end you will struggle in performance or finding workarrounds for sticking interfaces together.

As I mentioned in nearly every thread about this topic, go ahead and read that book: Game Engine Architecture, Second Edition
https://www.amazon.de/Engine-Architecture-Second-Jason-Gregory/dp/1466560010