1. Cleaning an XCode project erases the project bundle, which on the Mac is basically a sort of pretend folder that contains all the auxiliary data associated with a program as well as the executable itself.
2. So if you had put a whole bunch of junk into the "Resources" folder inside the project bundle, such as, say, all your shaders and XML files, they are gone. Oops, I guess I didn't have a proper understanding of how you're supposed to manage resources on the Mac. That's annoying, as since my last Time Machine backup was on Sunday that means I've lost a few changes to the shaders, but hey no big, the vast majority of it is safely stored in the project bundle in the backu --
3. Time Machine does not back up project bundles.
Last actual copy of the game data is from late January, right before I created the new SDL version of the engine. Realistically all of the XML was test data so I can live without it, but losing the planet shader is going to be a giant pain in the ass. Well, medium-sized pain in the ass... fine, it was like a page of code, but still, it was a hard page of code. Gah. The first time in my life I actually need backups, I've been doing them conscientiously, and surprise! It didn't work anyway! I love computers.