<div class="blog">
<h1 id="NAME">
-Getting people to use SDL Perl: Docs, API, and Distribution
+The Build Process of SDL Perl
</h1>
<div class="CONTENT">
-<h4><i>The road so far</i></h4><br />
-Things have been busy but fruitful. Our two core modules are getting to be a bit more stable. <a href="http://matrix.cpantesters.org/?dist=Alien-SDL+1.403">Alien::SDL 1.405</a> is behaving well. This foundational stability will start to show results in <a href="http://matrix.cpantesters.org/?dist=SDL+2.405">SDL</a> too I believe. Most excitingly the main developer of frozen-bubble is reviewing our <a href="http://search.cpan.org/~kthakore/Games-FrozenBubble-2.202/lib/Games/FrozenBubble.pm">Games::FrozenBubble</a> port to CPAN. All good and well, but to keep this project going we need to improve.<br />
+<p>A while ago I had a long chat with mst on why SDL uses Module::Build rather then Make. I told him it is a simple matter of code inertia. The existing Module::Build system has worked well for us so far. Never the less, he convinced me that switching to Make will improve debugging the Build system. But to be able to switch we will need to completely replace the Build system. I am not prepared to do that so I will just present the requirements so mst or someone else can at least attempt to switch.</p><br />
<br />
-<h4><i>Getting people to use SDL Perl</i></h4><br />
-After a long chat with a new SDL user on #sdl today, I realize we still have some way to go. Currently it seems we are lacking in a few areas. We can definitely use some feedback and help in these areas. <br />
+<h3>The Build Process </h3><br />
+<b> Alien::SDL </b><br />
<br />
-<ul><li>Tutorials/Documentation<br />
-</li>
-
-<ul><li>We have more docs now on http://sdl.perl.org but they suck</li>
-<li>What type of tutorials do you think will be good for beginners?</li>
-
-<ul><li>A project start to finish?</li>
-<li>Individual tutorials for various topics?</li>
-<li>What needs to go in SDL::CookBook?</li>
-</ul></ul>
-<li>API sweetness</li>
-
-<ul><li>SDL Perl depends on distinct C libraries</li>
-
-<ul><li>This makes naming conventions, data formats different the SDL:: namespaces</li>
-<li>How do people design this stuff?</li>
-
-<ul><li>We are hackers and we just go do stuff but I think this needs some prior thought</li>
-<li>Any takers?</li>
-</ul></ul></ul>
-<li>Distribution</li>
-
-<ul><li>If SDL scripts can be packaged up simply for game developers to distribute their games it will be a big plus</li>
-
-<ul><li>One way is a Wx::Perl::Packer clone</li>
-<li>Another is a CPAN/Steam clone that game devs can upload games too and people can point and click download games? </li>
-</ul></ul></ul><div>If anyone wants to help in these areas please talk to us on sdl-devel@perl.org. </div><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/3102167581424744259-7164362190686365958?l=yapgh.blogspot.com' alt='' /></div>
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+<p>SDL Perl depends on a few C libraries for a complete install. This is handled by Alien::SDL. First we look for existing SDL libraries and dependencies by doing a <a href="http://github.com/kthakore/Alien_SDL/blob/master/inc/My/Utility.pm#L581">File::Find</a> for headers. If these headers are found we present and option for the user to use those. We then store these locations in Alien::SDL->config options 'cflags', 'prefix' and 'libs'. If we do not have libraries available even for a minimum SDL installed ( SDL.h is not found). We provide several platform specific options. </p><br />
+<p>For windows we have a simpler process. We download<a href="http://github.com/kthakore/Alien_SDL/blob/master/inc/My/Utility.pm#L7"> prebuilt </a>binaries ( and checksum ) based on the user's selection and just copy them in to the right location. Again the 'prefix', 'cflags', and 'libs' is saved in Alien::SDL->config. </p><br />
+<p>For *nix/MacOSX we download sources and attempt to compile them. To be able to do this we download several other dependencies like libpng, jpeg and pango. You can see how we do this using hashes <a href="http://github.com/kthakore/Alien_SDL/blob/master/inc/My/Utility.pm#L404">here</a>. During the compile process we also apply patches as needed for the <a href="http://github.com/kthakore/Alien_SDL/blob/master/inc/My/Utility.pm#L430">sources</a>. Once this is done we can head to SDL Build.PL </p><br />
+<b> SDL Perl dependency resolution </b><br />
+<br />
+SDL's Build is responsible for linking the right libraries to the correct XS. If libraries are missing it will disable the component (not put it in SDL->config). <br />
+<br />
+<p>For example to build <a href="http://github.com/kthakore/SDL_perl/blob/master/Build.PL#L342">Image.xs</a> we require libsdl, libsdl_image and lib[jpg|png|tiff]. So we would check for these headers in the prefix provided by Alien::SDL->config. If they are not provided we will disable the SDL::Image module. </p><br />
+<p>More over the availability of each library is specified as a -DMACRO to the gcc compiler. This way we can prevent XS failures due to missing libraries using #DEFINES. Here the SDL_image macro is <a href="http://github.com/kthakore/SDL_perl/blob/master/Build.PL#L422">defined</a> and <a href="http://github.com/kthakore/SDL_perl/blob/master/src/Image.xs#L13">used</a>. The availability of the module is then available from <a href="http://github.com/kthakore/SDL_perl/blob/master/t/image.t#L20">SDL::Config->has()</a> <br />
+<br />
+<br />
+<b> Conclusion </b> <br />
+<p>This is a high level overview of our Build process, because frankly I hate traumatizing my brain with this again. Credits have to go to FROGGS and kmx for helping with this Build scheme. Hopefully my post have helped people at the very least appreciate the problem scope of this Build system. That said I believe a fresh written build system, with these requirements in mind, will be more then welcome.<br />
+</p><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/3102167581424744259-4514794130108689562?l=yapgh.blogspot.com' alt='' /></div>
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