7. FAQ: Glide? TexUS?

7.1 What is Glide anyway?

Glide is a proprietary API plus drivers to access 3D graphics accelerator hardware based on chipsets manufactured by 3Dfx. Glide has been developed and implemented for DOS, Windows, and Macintosh, and has been ported to Linux by Daryll Strauss.

7.2 What is TexUS?

In the distribution is a libtexus.so, which is the 3Dfx Interactive Texture Utility Software. It is an image processing libary and utility program for preparing images for use with the 3Dfx Interactive Glide library. Features of TexUS include file format conversion, MIPmap creation, and support for 3Dfx Interactive Narrow Channel Compression textures.

The TexUS utility program texus reads images in several popular formats (TGA, PPM, RGT), generates MIPmaps, and writes the images as 3Dfx Interactive textures files (see e.g. alpha.3df, as found in the distribution) or as an image file for inspection. For details on the parameters for texus, and the API, see the TexUS documentation.

7.3 Is Glide freeware?

Nope. Glide is neither GPL'ed nor subject to any other public license. See LICENSE in the distribution for any details. Effectively, by downloading and using it, you agree to the End User License Agreement (EULA) on the 3Dfx web site. Glide is provided as binary only, and you should neither use nor distribute any files but the ones released to the public, if you have not signed an NDA. The Glide distribution including the test program sources are copyrighted by 3Dfx.

The same is true for all the sources in the Glide distribution. In the words of 3Dfx: These are not public domain, but they can be freely distributed to owners of 3Dfx products only. No card, No code!

7.4 Where do I get Glide?

The entire 3Dfx SDK is available for download off their public web-site located at www.3dfx.com. Anything else 3Dfx publicly released by 3Dfx is nearby on their website, too.

There is also an FTP site, ftp.3dfx.com. The FTP has a longer timeout, and some of the larger files have been broken into 3 files (approx. 3MB each).

7.5 Is the Glide source available?

Nope. The Glide source is made available only based on a special agreement and NDA with 3Dfx.

7.6 Is Linux Glide supported?

Currently, Linux Glide is unsupported. Basically, it is provided under the same disclaimers as the 3Dfx GL DLL (see below).

However, 3Dfx definitely wants to provide as much support as possible, and is in the process of setting up some prerequisites. For the time being, you will have to rely on the 3Dfx newsgroup (see below).

In addition, the Quantum3D web page claims that Linux support (for Obsidian) is planned for both Intel and AXP architecture systems in 2H97.

7.7 Where could I post Glide questions?

There are newsgroups currently available only on the NNTP server news.3dfx.com run by 3Dfx. This USENET groups are dedicated to 3Dfx and Glide in general, and will mainly provide assistance for DOS, Win95, and NT. The current list includes:

3dfx.events
3dfx.games.glquake
3dfx.glide
3dfx.glide.linux
3dfx.products
3dfx.test

A mailing list dedicated to Linux Glide is in preparation for 1Q98. Send mail to majordomo@gamers.org, no subject, body of the message info linux-3dfx to get information about the posting guidelines, the hypermail archive and how to subscribe to the list or the digest.

7.8 Where to send bug reports?

Currently, you should rely on the newsgroup (see above), that is news.3dfx.com/3dfx.glide.linux. There is no official support e-mail set up yet. For questions not specific to Linux Glide, make sure to use the other newsgroups.

7.9 Who is maintaining it?

3Dfx will appoint an official maintainer soon. Currently, inofficial maintainer of the Linux Glide port is Daryll Strauss. Please post bug reports in the newsgroup (above). If you are confident that you found a bug not previously reported, please mail to Daryll at daryll@harlot.rb.ca.us

7.10 How can I contribute to Linux Glide?

You could submit precise bug reports. Providing sample programs to be included in the distribution is another possibility. A major contribution would be adding code to the Glide based Mesa Voodoo driver source. See section on Mesa Voodoo below.

7.11 Do I have to use Glide?

Yes. As of now, there is no other Voodoo Graphics (tm) driver available for Linux. At the lowest level, Glide is the only interface that talks directly to the hardware. However, you can write OpenGL code without knowing anything about Glide, and use Mesa with the Glide based Mesa Voodoo driver. It helps to be aware of the involvement of Glide for recognizing driver limitations and bugs, though.

7.12 Should I program using the Glide API?

That depends on the application you are heading for. Glide is a proprietary API that is partly similar to OpenGL or Mesa, partly contains features only available as EXTensions to some OpenGL implementations, and partly contains features not available anywhere but within Glide.

If you want to use the OpenGL API, you will need Mesa (see below). Mesa, namely the Mesa Voodoo driver, offers an API resembling the well documented and widely used OpenGL API. However, the Mesa Voodoo driver is in early alpha, and you will have to accept performance losses and lack of support for some features.

In summary, the decision is up to you - if you are heading for maximum performance while accepting potential problems with porting to non-3Dfx hardware, Glide is not a bad choice. If you care about maintenance, OpenGL might be the best bet in the long run.

7.13 What is the Glide current version?

The current version of Linux Glide is 2.4. The next version will probably be identical to the current version for DOS/Windows, which is 2.4.3, which comes in two distributions. Right now, various parts of Glide are different for Voodoo Rush (tm) (VR) and Voodoo Graphics (tm) (VG) boards. Thus you have to pick up separate distributions (under Windows) for VR and VG. The same will be true for Linux. There will possibly be another chunk of code and another distribution for Voodoo 2 (tm) (V2) boards.

There is also a Glide 3.0 in preparation that will extend the API for use of triangle fans and triangle strips, and provide better state change optimization. Support for fans and strips will in some situations significantly reduce the amount of data sent ber triangle, and the Mesa driver will benefit from this, as the OpenGL API has separate modes for this. For a detailed explanation on this see e.g. the OpenGL documentation.

7.14 Does it support multiple Texelfx already?

Multiple Texelfx/TMU's can be used for single pass trilinear mipmapping for improvement image quality without performance penalty in current Linux Glide already. You will need a board with two Texelfx (that is, one of the appropriate Quantum3D Obsidian boards). The application needs to specify the use of both Texelfx accordingly, it does not happen automatically.

Note that because most applications are implemented for consumer boards with a single Texelfx, they might not query the presence of a second Texelfx, and thus not use it. This is not a flaw of Glide but of the application.

7.15 Is Linux Glide identical to DOS/Windows Glide?

The publicly available version of Linux Glide should be identical to the respective DOS/Windows versions. Delays in releasing the Linux port of newer DOS/Windows releases are possible.

7.16 Where to I get information on Glide?

There is exhaustive information available from 3Dfx. You could download it from their home page at www.3dfx.com/software/download_glide.html. These are for free, presuming you bought a 3Dfx hardware based board. Please read the licensing regulations.

Basically, you should look for some of the following:

• Glide Release Notes
• Glide Programming Guide
• Glide Reference Manual
• Glide Porting Guide
• TexUs Texture Utility Software
• ATB Release Notes
• Installing and Using the Obsidian

7.17 Where to get some Glide demos?

You will find demo sources for Glide within the distribution (test programs), and on the 3Dfx home page. The problem with the latter is that some require ATB. To port these demos to Linux, the event handling has to be completely rewritten.

In addition, you might find useful some of the OpenGL demo sources accompanying Mesa and GLUT. While the Glide API is different from the OpenGL API, they target the same hardware rendering pipeline.

7.18 What is ATB?

Some of the 3Dfx demo programs for Glide depend not only on Glide but also on 3Dfx's proprietary Arcade Toolbox (ATB), which is available for DOS and Win32, but has not been ported for Linux. If you are a devleoper, the sources are available within the Total Immersion program, so porting ATB to Linux would be possible.