The gotcha with targeting for retina displays is that you will need higher resolution images across the board.
And, for something meant to fill the background, you will end up with images that are too big for Android devices (they have a maximum image size).
One way to go is have a High Definition version of your app with all graphics designed for only the retina display type devices. This is typically twice the resolution (sort of) of the normal iPad device and can be made only for that one.
Assuming that you are using Tier 1, this is relatively easy. You have two Xcode projects, one for normal and one for high def. In the normal one, you have all the media in the normal resolution. In the high def one, create the same media but at double the resolution.
Now, in your AppGameKit project, create a constant value that is either set to 1 (for normal) or 2 (for hih def). Then anywhere in your code that you size, position or move something, use that multiplier on both the x and y values. Then set it for 1 and build the app. Copy the byte code file over to the normal Xcode project. Then set the constant to 2, build the app and copy the byte code file over to the high def Xcode project.
A sort of example:
// define the multiplier
#constant mul_by 1.0
// other stuff
// create a sprite
img = LoadImage("someimage.png")
spr = CreateSprite(img)
// size the sprite
SetSpriteSize(spr,125.0*mul_by,30.0*mul_by)
// position it
SetSpritePosition(spr,250.0*mul_by,305.0*mul_by)
Since you are only worried about the retina display for iOS, you don't need to keep the high def images in your AppGameKit project or use them in Android builds.
You might use them for Mac, if you want to do a high res version there.
And, the only environment for doing the iOS and Mac stuff (at this time and required by Apple) is on a Mac in Xcode.
Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master
