Making a GUI using Qt for a text-based game - c++

Question

Me and my fellow classmates decided to make a game over the summer. At first we decided to make it a text-based console app, but then I though that it would be possible to create a GUI for the game using Qt. I played around with it a bit, being able to create widgets and what-not, but was unable to do one thing. For an example, our game contains a Player class. I created a dummy player in the main.cpp and afterwards tried to make the players info to display on a label on a press of a button. After numerous attempts, the only way I was able to do it is by making the player in the mainwindow.cpp . Is there a way to display the info of a player made in the main.cpp? How would it be possible to make the data accessible by different windows, such as the battle window, inventory window, etc.

Answer 1

It's a good thing to let the main.cpp as lean as possible, it should not contain much code in your case.
If I understand correctly you have several windows (could be simple QWidgets with no parent or QMainWindows) running on the same QApplication and your want to share data between them ? Why not just share a Player pointer in both your windows ?
Your main.cpp will look like this:
QApplication app(argc,argv);
YourWindows1 mw1;
YourWindows2 mw2;
Player player;
mw1.setPlayer(&player);
mv2.setPlayer(&player);
mw1.show();
mw2.show();
app.exec();
A more fancy way, could be to use a singleton. This singleton could own and hold your Player instance, every windows can access this singleton statically anytime to fetch Player information. It could be something useful for you to learn.
NOTE: I don't see exactly what is the problem here, perhaps you could share more details about what's causing you trouble ...

Answer 2

In a typical Qt app, main.cpp is only there to start the single application UI object and then turn control over to Qt's event handler. It's possible to deviate from that model, but unless you're quite experienced with Qt it's not something that would be recommended.

Answer 3

I agree with the other posters in this thread in that your main function should be kept absolutely as lean as possible. You want it simply to spawn a new instance of your game, and the let the game loop or state control manager take care of the rest. It basically boils down to something like this:
class Game{
Game();
~Game();
int OnExecute();
};
int Game::OnExecute(){
while(running){
// do game stuff
}
return 0; // No errors, game closed correctly.
}
int main(int argc, char* argv[]){
Game myGame;
myGame.OnExecute();
}
All of your initialization methods/code is contained within the OnExecute function, prior to the game entering its main loop. Within that main while(running) loop, you put your calls to your per-frame Update and Rendering functions which control logic calculations like entity position, physics updating, AI updating, etc and then you render everything for that frame. This is obviously an ultra-simplistic strategy, but it definitely helped me grasp exactly how it is that game engines work.
Now, as far as Qt is concerned, I've tried exactly what you are trying and it is not easy. Qt, though it can be rigged to work for in-game interfaces and the like, seems to me to be primarily intended for use in applications more than games. It provides excellent functionality if you need simple forms and buttons in your program, but as far as custom-designed HUDs and such, you're going to want to look somewhere else in order to save yourself a great deal of hassle. There are, however, a huge number of extensible GUI libraries specifically meant for games. I would suggest looking for one based simply on OpenGL since most graphics/game engines are built upon it and would integrate quite nicely.