Unity is one example, another would be libGDX[0]. A game engine will give you a blank window, like an OpenGL context, which you draw raw onto. Any decent graphi

Unity is one example, another would be libGDX[0]. A game engine will give you a blank window, like an OpenGL context, which you draw raw onto. Any decent graphics library will provide useful functions for drawing 2D and 3D graphics, updating the screen, handling input, etc. to make using it easier. Making a typical UI application means reusing lots of widgets provided by the OS, like buttons and sliders, to keep things consistent and make development much faster. If you tried to build a normal UI app inside a graphics engine, you could do it, but you would have to build all widgets from scratch and it wouldn't look like a native UI app. [0] https://libgdx.badlogicgames.com/ https://libgdx.badlogicgames.com/