Friday, August 2, 2013

More Configurations, MinGW, and Midterm for GSoC


Halfway done with Google Summer of Code. I have a few quick updates to discuss and then I have a request for the SDL community.

Complex Configurations (pt. 2)

I discussed in my last post how I added support for complex configurations by allowing SDL projects to set preprocessor definitions that would be embedded with a configuration header file that drives the entire SDL build process. This is the same way taken by ./configure and related Linux systems. The system has been implemented at this point and has allowed me to do some interesting stuff.

First of all, the modularity of SDL is much more customizable now than it was previously. I can disable DirectX or OpenGL support with ease. If the meta-build system cannot find one or both of these dependencies, it will appropriately configure SDL to neither compile its related modules nor link to the resulting modules. It becomes rather convenient. I theorized in the beginning of my project that SDL should be able to be built and used on Windows without DirectX support. Recently, I have successfully built and ran all the tests without DirectX support. It works surprisingly well. There are a feel hiccups in the test suites, but that's expected given this was mostly untested behavior prior to this meta-build project.

I hope to expand the configurations systems to new depths by providing command-line arguments for easily enabling and disabling whole modules of SDL, without having to have any previous knowledge about its configuration systems or the meta-build system itself. As this project evolves to more a more modular design, this customization will prove to be very convenient and beneficial. SDL can literally be built dozens of different ways on some systems and I would really like to try and capture that with as much ease as possible. The only thing the end user would need to be aware of is which dependencies SDL has, which can be easily documented.

Full Test Suite

I forgot to mention this in my last post, but I did add support for building and linking the entire SDL test suite to every platform supported. Originally, the Visual Studio portion of SDL only had 10 tests supported. The Xcode version had a few more than that. It turns out there are 42 tests part of the SDL test suite. I was a bit shocked when I noticed I wasn't targeting most of them, so I worked to add support for the whole lot. I've written a lot of convenient build scripts (as I will discuss later) for making building and running these tests as painless as possible.

Mac OS X: Multiple Architectures

I am beginning to look into multiple architecture support, starting with Mac OS X. Currently, the Xcode projects should support building to architectures i386 and x86_64. I am planning on implementing Universal binaries for Mac OS X and any platform that has GCC, so including Windows through MinGW and Cygwin, as well as any Linux platforms. This is continuing the current support for "fat" binaries that SDL offers.

MinGW Support

I decided to be a bit adventurous this week. I implemented MinGW support using GNU makefiles. I hope to expand this project to full make support, but I needed to start with something that would not involve a lot of changes to the current project. MinGW is targeted for building native Windows applications using GCC and the GNU toolchain. Essentially, that implies the Windows setup to project generation is not much different between Visual Studio and MinGW. In some parts this is true, but in others...not so much.

The major differences are in the path separators and the different compilers (obviously). I had to create a MinGW mode (using the --mingw command line option) to signify using POSIX paths, etc. Beyond that, I ran into a lot of trouble over properly linking to the main function of the test applications. I had to use the linker argument -lmingw32 to GCC, though premake was giving me a lot of grief by making it only possible to put it in the wrong place. At the end of the day, I had to modify premake and change the order it generates its linker arguments in the resulting makefiles.

The only other problem with the MinGW support is GCC cannot compile the DirectX and Windows SDK header files correctly. There are MinGW alternatives to DirectX, but these are not the easiest things to work with. I've encountered some problems working with them and I know a bunch of other people have, too. As a result, I am not going to support DirectX with the MinGW generation option. I do plan on adding an override command line argument to the meta-build system for generating MinGW projects that still link to DirectX regardless of it being MinGW, leaving it up to the fate of the developer to try and get the thing to link properly.

Google Summer of Code Midterm!

I have to say I'm a bit surprised that it's already the halfway point. Time does fly when you're really focused on a project. Nevertheless, I am hoping the SDL community is able to help me at this point by pulling my repository and tinkering with it. Please, if you have time, try to give the meta-build system a whirl. The currently supported platforms are Windows using Visual Studio and MinGW and Mac OS X using Xcode. Here are a few things to note:

Obviously the system is very experimental. That's why it needs to be tested. If something goes wrong, feel free to email me, comment on this blog, or post it on the mailing list. I will see it and get back to you very soon. I appreciate any problems or feedback you have.

If you want to just give a quick contribution to the project, simply build the SDL project and test suites for whichever choice platform and IDE. If you run the tests, it can give a quick feedback about whether SDL seems to run mostly normally on your system using the build configurations setup by the meta-build system. I have created several build scripts for each platform for handling various types of builds, as well as testing those builds using the extensive SDL test suite.

If you want to give a more elaborate contribution, I would really appreciate you testing binary compatibility or interoperability by either building or linking any SDL projects you have or are using against the libraries produced by the meta-build projects. This would give excellent feedback as to whether I am correctly generating the projects and that they are behaving as they should so far.

I really appreciate any and all help so far.


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