I’m sorry if this has been discussed before, but my searching didn’t turn up anything.
I know sprite sheets are limited to a size of 2048*2048 on iOS, but I’m not sure what the constraints are for loading multiple sprite-sheets at the same time. I know it’s probably device and maybe texture specific, but are their general rules of thumb? Is it reasonable to consider loading two 2048*2048 sprite sheets at the same time? What about 5?
Careful though, iPod 2nd Gen, iPhone 3G and anything lower all have a max of 1024×1024. You’ll get crashes when lower devices request sprite frames on 2048*2048 textures.
That aside, I don’t know actual constraints on number loaded at once, but I know I’ve had at least 9 or 10 1024 sheets loaded at once. This was, however, inefficient of me and with the use of a sprite packaging tool like Zwoptex, you can save a LOT of room.
I personally find that on the iPhone 3G (not 3GS), if your using a box2d tick and have a reasonable amount of sprites + sounds, 2 1024×1024 spritesheets is about maximum that runs at 60fps without memory warnings.
That’s just what i’ve found myself, textures are only part of your game, loading 5 might be possible if the load from your game methods/tick are low.