In Preparing for Mac App Store Submission, the first set of changes you should make are to the project itself.
This installment describes the project modifications that need to be made to an existing Mac OS X game project. The general assumptions are that the existing project is working and properly tested, and that, ultimately, you will want to maintain a single set of source code with conditional compilation to differentiate the store version from other builds. Note that these are the steps that we took for Pretty Good Solitaire Mac Edition; your project may require some adjustments to these steps. (Comments where any significant change is necessary would be very appreciated.)
So, without further ado…
0. Create a duplicate store project
Before making any other changes, create a duplicate copy of the entire project folder and name the copy appropriately. In our case, the original folder was ‘Pretty Good Solitaire’ (which builds full and trial versions of the game) and we created a separate ‘pgsse’ (Pretty Good Solitaire [Mac/]Store Edition) folder for MAS modifications.
The version of your project that you will submit to the Mac App Store is a separate SKU (Shelf Keeping Unit), a build that uses slightly different code and configuration and which is distributed via a different channel. While it is possible to have the store target within the main project, certain features (e.g., Power PC support, Mac OS X 10.5 support, downloadable data) are not supported in MAS, so it is easier to separate them (at first, anyway). In any event, doing so at the start gives you a safe playground for making changes without messing up your working project.
1. Update the project version number
As just noted, the store build is a separate version and, thus, should have a different version number. In our case, we decided that odd minor versions (e.g., “1.01″) would represent the store editions, while even minor versions (e.g., “1.00″) represented the direct downloadable editions.
2. Rename the primary build target
In the new project (of course), rename the primary build target to something appropriate. In our case, we renamed the full version target to ‘Pretty Good Solitaire store’, which is now the store version. You could also delete any redundant or obsolete targets remaining in the project. For example, we deleted the trial version target, as it is built in the original project and the MAS version cannot have any vestiges of a trial version.
Note that this step is not strictly required, but it is a good idea to differentiate between targets, so it is always immediately obvious which project is active, and also to minimize any excess baggage, which reduces the possibility of mistakes.
3. Build with a current Xcode version
Make sure that you build the project with a current version of Xcode. Submissions to the Mac App Store now require Xcode 4 and, as of this writing, the latest version is Xcode 4.2.1.
If you have an older version of Xcode, this would be a good time to upgrade, and although it will not be mentioned explicitly, you should build the project regularly, ideally after every change, to make sure that the build is not broken and behaves as expected.
4. Define a preprocessor variable
To allow for conditional compilation of certain source code, it is a good idea to define a preprocessor variable, APPSTORE, for any build targets intended for MAS. In the ‘Build Settings’ for the target (or the whole project, if you prefer), find the setting for ‘Preprocessor Macros’ and add “APPSTORE” to each configuration. Note that it is common to have different variables for ‘Release’ and ‘Debug’ configurations, so be careful to define APPSTORE for each one without accidentally removing or altering any existing definitions.
Of course, there is no requirement that the preprocessor variable be named “APPSTORE”, but beware that simply using “STORE” results in a naming conflict in the latest Mac OS X SDK.
5. Add necessary frameworks/libraries
In order to test the validity of app receipts, you will need to add the IOKit and Security frameworks and the crypto library. From the ‘Build Phases’ of the primary target, open the ‘Link Binary With Libraries’ section and, by clicking on the ‘+’ symbol, add ‘IOKit.framework‘, ‘Security.framework‘ and ‘libcrypto.dylib‘.
Note that Xcode 4 adds these frameworks/libraries at the top level of your project; you will probably want to drag them into the ‘External Framework and Libraries’ folder with the other frameworks.
6. Configure debugging symbols
Despite submitting a release version to MAS, Apple requires debugging information to be included with a submission. To accede to this requirement, you must set ‘Generate Debug Symbols’ to “Yes” and also set ‘Debug Information Format’ to “DWARF with dSYM File” (at least for the ‘Release’ configuration) in the ‘Build Settings’ of the target.
In our original project, we had all debug information disabled and/or stripped from the release builds, but one of our early issues was the lack of the dSYM file with debugging information for Apple.
7. Set correct build architecture
Finally, set ‘Architectures’ to an Intel (only) setting; for our project, that is “32-bit Intel”.
Even if your code and original project supports both PPC and Intel via a “Universal” application, the presence of a PPC build in your submission will result in rejection. (We found that out the hard/lengthy way.) At least now there are settings for this; in Xcode 3, you had to use “i386″, which was not even listed as a choice.
At this point, you should have a new project with a store target and all of the build settings configured appropriately. In the next installment, Part 2: Property List (Info.plist) changes, we will discuss the necessary adjustments and additions to the information property list for your project.