I'm a beginner/hobbyist game developer. Can anyone recommend some books or sites with tutorials that covers this aspect of game development. Designing and creating a user game interface subsystem in-game sounds difficult, it's like re-creating a new windowing system within another (a game inside win32 windowing API). I can hardly imagine how I would go about creating one (beginner of course), but I thought about it but couldn't figure out. Since a game has only a main game loop, a GUI subsystem would have to poll user input from keyboard, mouse or other various inputs, then update the states where I would draw or render the correct UI elements/widget in-game. I'm confused, please help me out. :P I guess most game API such has a built-in windowing subsystem with a handful of limited widgets. Some don't like Ogre3D, which doesn't have one but it's accompanied by something they recommend, can't remember what they recommended as part of their SDK. I tried what is offered by DirectX in one of their SDK examples. Well, that is 1 possible example I can follow, but is that the good enough? Is it a standard on how I implement such a GUI subsystem in-game. Will it be responsive enough to react to user input, not lagging while I enter some text into the text box and such. Most importantly, how do all these GUI subsystem work in a single game loop can it be event-based rather than poll-based? Thanks.