<div class="blog">
<h1 id="NAME">
-Why and How Frozen Bubble is going to CPAN
+The Build Process of SDL Perl
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-<div style="text-align: right;"><i>A single drop,</i><br /></div><div style="text-align: right;"><i>causes the ocean to swell</i><br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;">So 5 weeks ago, SDL Perl was broken. It had been for several years. After the last release SDL Perl works ... somewhat. The quick releases that you have seen have been work-arounds, fixes and refactoring. This is not bad for a few weeks of work but, there is a point where code smell and technical debt is too huge to fix with out redesigning. This is that point.<br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Since the redesigning will take time and effort it will be good to have a leg up. This leg up is Frozen Bubble 2.20. Frozen Bubble employs a lot of C and Perl hacks to cover up for SDL Perl's lacking. This will help in a sense fast forward the code status to 2008. Since Frozen Bubble is helping us out, we can go one step forward and help it out! <br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;">So Alias (Adam Kennedy) and I have started work on making Frozen Bubble CPAN accessible. Frozen Bubble is a well know game and making it cross-platform will bring lots of attention and hopefully contributions to SDL Perl.<br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;">In Alias's <a href="http://use.perl.org/%7EAlias/journal/39701">earlier post</a> about this he mentioned about making a splash and some other stuff. I will talk about how and where we will be accomplishing this task. <br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;">First we will be tracking Frozen Bubble on the new <a href="http://sdlperl.ath.cx/projects/SDLPerl/wiki">SDL Perl Trac website</a>. This site will be similar to Padre's Trac site. As a bonus for people looking to help out in SDL Perl I have separated tasks by <i>perceived </i>difficulty. This will help to breakdown harder task too.<br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;">For example for Frozen Bubble the two major bumps we have run into so far are:<br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;">Migrating the SDL Perl workarounds: <a href="http://sdlperl.ath.cx/projects/SDLPerl/ticket/3">Ticket #3</a><br /></div><div style="text-align: left;">Making the Build System Portable: <a href="http://sdlperl.ath.cx/projects/SDLPerl/ticket/7">Ticket #7</a><br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;">The first one will be difficult as it involves XS. So I will break it down into easier tasks with specific instruction which can then hopefully be picked up by interested contributers. The second one there is sort of a forte of Adam so I will leave it up to him. This is the process I am proposing make hard tickets, break them down.<br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;">This will generate a lot of easy tickets that will hopefully be synchronized. If you are interested in this please give me a shout on #sdl irc.perl.org or the mailing list at sdl-devel@perl.org and I will get you registered.<br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;">--yapgh<br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><br /></div><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/3102167581424744259-1296050942449452224?l=yapgh.blogspot.com'/></div></div></div>
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+<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 />
+<h3>The Build Process </h3><br />
+<b> Alien::SDL </b><br />
+<br />
+<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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