title: "Sprite Pack" for room themes in level generation. Unity3D
body: <p>So I was wondering if there is a way to "repack" sprites to be a theme. I got 1 image with all the stage sprites I need and I basically wondered if I can keep them in that 1 image and then have "links" or something to a seperate pack.
  I thought of doing a "Theme" class and then create instances of that to match my themes, with variables hardcoded to match. But I can't believe there isn't a better way.
  I hope I've explained this well enough ^^</p>