Porting the Audio Libraries to UWP

The Task:

    Getting CMake to properly work with Gateware Win32 and UWP projects was no simple task but since it was finally done, I was able to start porting Gateware to UWP in earnest. I was given the choice of what to start with, I chose the audio libraries as it seemed like an (almost) one to one port was in the cards. I was right, but it didn't come without its issues.

The Problem:

    My initial evaluation of the audio libraries had me changing just a few functions here and there that were not available for UWP apps. This assumption did turn out to be correct but with some caveats. I based all of the UWP implementation of the GAudio libraries off of the Win32 ones as they are all build using XAudio2 which is compatible with UWP. After changing some key functions that were not compatible, ex. CreateFile() to CreateFile2(), I got everything compiling. Success? No, not really. When I would then run the Unit Tests, the program would call abort() from somewhere.

The Solution:

    The first thing to do was to find where abort() was being called from. Using the debugger I was able to track it down to the CreateFile2(). I was very surprised to find this as the documentation for the function says it is compatible with Windows Store apps. After reading through it again more thoroughly, I found this "When called from a Windows Store app, CreateFile2 is simplified. You can open only files or directories inside the ApplicationData.LocalFolder or Package.InstalledLocation directories." Knowing that I have not done anything with file I/O yet with any of the libraries, I knew pretty quickly this was the issue.

    Getting to the installed location of the app is done pretty easily with WinRT calls so that was not the hard part. Getting the Unit Test Resources, such as the audio files, in the installed location is what stumped me for the longest time. This is easily done in Visual Studios by just including it in the project and setting it to "content" in the properties but this needs to be done before a dev even opens up the project. Back to CMake I went as I already had the Asset folder being put in as content for the UWP app, so I figured it would not be any different for another folder. I was right in that thinking, it just took a lot of trial and error to get it just right.

    With that out of the way, I was able to get the sound files from the installed location and everything compiled and ran perfectly.

   As of right now, all audio unit tests pass.