Yesterday I received another report for a game, which wasn't working with the wine-unstable packages built by me. The reason why the reporter wrote to me and suspected a bug in my builds was, that the same game worked on the system of a friend (using a different distribution). After some exchanged e-mails it became apparent that this was yet another installment of S3TC-compressed textures. And as this wasn't the first time I got such reports, I thought I blog about the solution today.

As S3TC is one of those patent-encumbered texture compression formats (don't ask me why one can get a patent for such things, it's, IMHO, a very bad thing and we'd be better off, with a lot less patents), Mesa doesn't support it out of the box. You need to install an additional library or the proprietary driver for your graphics card. Before installing the library, make sure, that it is legal in your jurisdiction (i.e. check whether the patent is valid in your jurisdiction). If that is the case, you can install libtxc-dxtn0 from the Debian Multimedia repository or compile it yourself from source. If the patent is valid in your jurisdiction, you're most likely required to get a license from the rights holder for using the library, but I'm no lawyer so you might want to consult one prior to making your decision.

For amd64 users, there is an additional caveat: Wine needs the 32 bit variant installed. At the moment, this means downloading the i386 package from debian-multimedia.org and extracting the library to /usr/lib32.

For users with the r600c/g driver it gets (currently) really tricky, as there is no fully working support for loading libtxc_dxtn.so (current status is WIP). Here the only solution I know, would be to use the proprietary driver or writing patches for r600g (last option preferred *g*).

Just two days ago I wrote about S3TC-compressed textures and that it is a little bit tricky for amd64 users to get the correct libraries installed. Since then I've been in contact with Christian Marillat, the guy behind debian-multimedia.org and he immediately responded with uploading ia32-libs-libtxc-dxtn0 to make it easier to install the 32 bit variant of libtxc_dxtn0 on 64 bit platforms.

A big Thank You! to Christian! And if you find his service helpful, consider donating to him (I can only guess at the amount of traffic he gets, especially since a lot of people certainly don't use one of the mirrors). (Just a short disclaimer: Christian didn't ask me to put the donation request in this post, in fact he'll only know about it, as soon as this goes online.)

I'll add an Suggests: in the next upload of wine-unstable to the server on libtxc-dxtn0/ia32-libs-libtxc-dxtn0 so people'll have an easier time to get S3TC working. But again: before installation: make sure it is legal for you to install the library.

Thanks to the awesome patent situation (if you're unaware of what I'm talking, you can catch up by listening to PRI's This American Life episode about patents, reading Florian Mueller's write-ups about the patent wars (current focus: mobile devices) or by having a look into my posts with the "patent-mess" tag), Debian will most likely be unable to distribute Mesa packages with ARB_texture_float enabled (if you want to build mesa yourself with this extension enabled, just add --enable-texture-float to confflags-dri in the Mesa source package's debian/rules). But some programs really like to have this extension, thus I started building Mesa myself. The resulting packages can be found on dev.carbon-project.org.

Big fat warning: please check, whether you're affected by the US patent #6,650,327 (i.e. if it's a valid patent in your jurisdiction) before you use the packages. If in doubt, consult with your lawyer.

By the way, if you're not working in an area where knowledge of the specifc claims/content of the patent might be harmful, you have some time on your hands and you want to learn, what's "patentworthy" these days, have a look at the claims of the patent. Otherwise the three links from the beginning must do.

Before I end this post, just one more remark about my Mesa packages: they'll follow upstream's Git and thus might have problems from time to time. If Debian's Mesa packages suffice your needs, stay with them. If not, feel free to use my packages or use them as a base for your own packages.