Adams on Carbonizing UT, Music Issues
2:23 PM | Michael Eilers | Comment on this story
Of all the past-published titles that IMG readers want to see ported to Mac OS X, we're fairly sure Unreal Tournament tops that list. After all, Quake 3 Arena fans are certain to have a native Cocoa version of that shooter once id completes their optimization -- UT fans don't want to be left out.
While the Carbonizing of Unreal Tournament is not an official Westlake project, president Mark Adams has let it be known that he is indeed working on Carbon UT in his spare time. Obviously there are several issues to be dealt with, such as converting networking and input device support to native APIs and switching from RAVE to OpenGL as the preferred rendering method. However a recent discussion on Apple's "devlist" mailing list for developers has revealed another potential pothole in the road to a native UT port -- the music system.
The PC version of Unreal Tournament uses a music format known as "mods" or "modules", songs that are packaged not as an audio data file but as a series of instrument samples and MIDI-like sequence commands for playing these samples back. The MOD format is as old as music on computers, dating back to the Amiga platform, and is a common way to handle video game music. Rather than port the PC MOD player from UT to the Mac OS, Westlake chose to use an open-source MOD player created by Zerius which was famous among developers for its low CPU overhead and playback quality. One of the ways the Zerius player achieved this performance was by being partially written in PPC assembly code, the hallmark of many of their projects.
Unfortunately, according to notes on the devlist, the Zerius team has vanished and thus the source code of this player is no longer available for developers to Carbonize. As a result Mark Adams found himself with a nasty, unexpected problem on his hands when dealing with UT's music system:
I hit this during my "how bad could it be, I'll carbonize UT in my freeZSS refers to the Zerius playback system, while MADLibrary is a MOD playback system developed by the author of the tracker/sampler Player Pro. Hopefully this MADL player is already or will soon be Carbonized, and work on the Carbon ports of UT (which may very well result in Carbon ports of Rune and Deus Ex, although neither has been promised or even looked into at this point) can proceed apace.
time!" work just last week. ACK! It was all I could do to keep from
running screaming from the office when I realized our use of ZSS was going
to be a big mess as far as OS X.
I'll have to check out the MADLibrary source listed here, maybe that will
It is interesting to note that sound formats have also been a barrier for another Mac port involving the UT engine, namely the port of Star Trek Deep Space Nine: The Fallen to the Mac OS. The PC version of that game used a playback system known as the Miles Sound System, which did not exist for the Mac platform until recently, even though it has been used for over 2000 games on the PC.
While the two problems faced by these UT engine developers are not directly related, it does reveal another aspect of porting games that most end-users aren't aware of -- the fact that many games use some "off the shelf" components as part of their code, and developers working on a port may not have access to the source code of those pre-made parts and have to "make do" with their own versions. As for those who would ask, "why don't the developers just change the music/sound format to one that works," -- this is a good question, but in most cases a developer porting a game is prevented or strongly discouraged from changing the actual data format of a game, in the interest of maintaining compatibility with the PC version.
We will continue to follow the progress of both Carbon UT and the Mac OS port of Deep Space Nine: The Fallen (which is currently expected to be a 'Classic' app) and report any new developments.
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