Now multiply by 20 screens and add large backgrounds
And yeah atlas is huge PITA. Especially when you have hundreds and hundreds of interface images.
C4 supports them for GUI and it's the default way but I don't end up using them. Thought it would eventually give me a performance hit but I've been surprised that it doesn't do shit.
And stuff that's not visible doesn't get rendered, and if nothing changes it doesn't readjust its size and 50 other nonsense things Unity and some other GUI systems do. Plus there's a little wysiwig editor that even a complete idjit could use.
And you can build these interfaces directly in your game, like on a slot machine, nuclear reactor controls, a television set with actual video, etc. And there's never anything that gets rendered all messed up.
It's almost like someone competent programmed it all! Amazing what happens when that's the case.