"Linux Gazette...making Linux just a little more fun!"

  

Set your browser as wide as you'd like now.  I've fixed the Muse to expand to fill the aviailable space! © 1998 by mjh

 

muse:  v; to become absorbed in thought  n; [ fr. Any of the nine sister goddesses of learning and the arts in Greek Mythology ]: a source of inspiration   elcome to the Graphics Muse! Why a "muse"? Well, except for the sisters aspect, the above definitions are pretty much the way I'd describe my own interest in computer graphics: it keeps me deep in thought and it is a daily source of inspiration.  [Graphics Mews][WebWonderings][Musings] [Resources]

I also got not just a few letters that were a little less than friendly.  So to them, I'll put it plainly - convince the commercial X server vendors GGI is a good idea and I'll believe it.  I trust them.  That said, I should also point out that as a reader of this column you should make your own decisions.  Go to the GGI Web site and read their material.  Don't trust it simply because you read it here.  Writers make mistakes too.  The web makes it very easy to distribute information, but there are very few checks in place to force writers to be accurate.  The morale:  verify your information with more than one source.

One other thing:  one responder very politely suggested that I should know more about what I write before distributing it in a place that carries such "authority" - the Linux Gazette.  He is correct:  I need to try to be as accurate as possible.  But to those who were not so polite, try to remember:  this is just a hobby.  I'm not really a graphics expert and I do get things wrong.  If you're going to nudge me in the right direction, please do so politely.  And please, no more email on GGI.  The kernel team is better qualified to decide GGI's fate in Linux than I.  I'm not even certain any of the kernel developers read this column!
 
Ok, on to the work at hand.  This month I conclude the two part status update on X servers with information on Metro Link.  Last month, if you recall, I covered XFree86/S.u.S.E and Xi Graphics.  Also in this months issue of the Muse is a little bit of information I gathered while trying to find some decent offline storage media.  I'll kill the ending - I ended up with an Iomega Jaz drive.  But you'll still want to read about why I chose it and what it takes to install the beast.

Finally, I do a little review of XFPovray.  This is an XForms based front end to POV-Ray, the 3D raytracing engine.  I used it recently in working on another cover for the Linux Journal.

Enjoy!

        Disclaimer: Before I get too far into this I should note that any of the news items I post in this section are just that - news. Either I happened to run across them via some mailing list I was on, via some Usenet newsgroup, or via email from someone. I'm not necessarily endorsing these products (some of which may be commercial), I'm just letting you know I'd heard about them in the past month.
 

XFree86 3.3.2 is released XFree86 version 3.3.2 is now available.  The XFree86 3.3 distribution is available in both source and binary form.  Binary distributions are currently available for FreeBSD (2.2.2+ and 3.0-CURRENT), NetBSD (1.2 and 1.3), OpenBSD, Interactive Unix, Linux (ix86 and AXP), SVR4.0, UnixWare, OS/2, Solaris 2.6 and LynxOS AT.  The XFree86 documentation is available on-line on their Web server.  The documentation for 3.3 can be accessed at http://WWW.XFree86.org/3.3/.  The XFree86 FAQ is at http://WWW.XFree86.org/FAQ/.  The XFree86 Web site is at http://WWW.XFree86.org		Moonlight Creator - 3D modeller There's a relatively new GPL modeller available. It's call moonlight creator and can be found at http://www.cybersociety.com/moonlight/  This modeller generated almost as much email as my comment on GGI - and I didn't even say anything about it last month!  Pad++ The NYU Center for Advanced Technology has released a new drawing tool with some object placement and scaling features possibly worthy of attention as they continue to extend The Gimp.  Precompiled binaries for several flavors of UNIX.  http://www.mrl.nyu.edu/  Click on Pad++.
LParser Source Code Released Laurens Lapré has released the source code for his popular LParser tool.  LParser creates 3D forms using a descriptive language called an L-System.  It can be used to produce 3D trees, plants and other organic items.  Output formats include VRML, POV-Ray, and DXF.  On his web page Larens writes:  Source code of the lparser ZIP file (18Kb) can also be downloaded, for those who want to port or just play with new options. The code is straight, no frills ANSI-C with even less documentation but it should run on pretty much anything with a C or C++ compiler. My current job will leave me with neither the time nor the inclination to do serious code hacking so I'm throwing the code into the wind, hoping that it will germinate and produce lots of mutated offspring ! The Lparser source may be freely distributed. The Web page for the LParser tool is at http://www.xs4all.nl/~ljlapre/.		SART - 3D Rendering Library for Guile SART is a 3D rendering library for Guile. It supports zbuffering, raytracing and radiosity, with advanced textures, and image processing and other features. This is the first public release announcement, as the 0.5a2 version is in the developers opinion sufficiently stable and simple enough to compile to meet a wider circle of developers (and even users).  SART is freely distributable under GPL. To read more, visit the webpage:  http://petra.zesoi.fer.hr/~silovic/sart  The develper asks:  Now would somebody help me interface this thing with script-fu and/or guile-gtk?

BMRT 2.3.6 Announcment:

Hello, and thanks to everybody for putting up with my extended Beta period.  They say each new group of users discovers a new class of bugs.  Indeed, with the BMRT port for Windows and the nice RIB support of Rhino (www.rhino3d.com), lots of difficulties with trimmed NURBS came to the surface and were subsequently fixed.  Thanks to those who stuck it out with me.

BMRT 2.3.6 is finally officially shipping.  Er, well, you know what I mean -- it's on the FTP site.

Please get the latest and replace the beta, if you had it.  I managed to squash many bugs in the beta, and also reduced both time and memory by about 15% for large scenes!

Other News: Tony Apodaca and I are co-organizing a course for this summer's Siggraph conference.  The course is titled "Advanced RenderMan: Beyond the Companion", and will taught by myself and Tony, Ronen Barzel (Pixar), Clint Hanson (Sony Imageworks), Antoine Durr (Blue Sky|VIFX), and Scott Johnston (Fleeting Image Animation).
Hope to see some of you there!

Enjoy the software,

        -- lg
 

Did You Know?

VRML spec to drive 3D on Net
By Erich Luening
Staff Writer, CNET NEWS.COM

http://www.news.com/News/Item/0,4,19992,00.html

...a description of the Kodak DC120 .KDC File Format can be found at http://www.hamrick.com/dc120/.  This format is the one used by the popular Kodak DC120 digital camera.  There is Windows command line source there for converting the files to JPEG or BMP formats.  Anyone looking for a project might look into porting this to Linux for use with, for example, NetPBM, ImageMagick, or the GIMP.

...and speaking of digital cameras, did you know there is a small software package called PhotoPC for Linux that supports a number of digital cameras, including:  Agfa, Epson PhotoPC models, Olympus Digital cameras line, Sanyo, and Sierra Imaging.  Take a look at the PhotoPC Web page at http://www.average.org/digicam/.

...there is a good editorial on the future of games on Linux at Slashdot.org.  The editorial was written by Rob Huffstedtler.  Its a good piece, and I have to say I agree with Rob's sentiments about commercial software - it isn't evil and shouldn't be viewed that way.  Any development on Linux - free or commercial - helps spread the word.  Linux isn't just about free software.  Its about having a choice, whether you are a developer or a user.

...the address for the AMAPI modeller has changed (I don't know how long ago this happened, but I was just notified by a reader):

ftp://sunsite.unc.edu/pub/Linux/apps/graphics/modeling/amapi.linux-elf.us.tar.gz
or
http://sunsite.unc.edu/pub/Linux/apps/graphics/modeling/amapi.linux-elf.us.tar.gz

Reader Mail

Just want to drop a line thanking you for your effort at the Gazette and with Linux.  Really, thanks a lot.

Tristan Savatier ([email protected]) wrote:

In Issue 26 of the Linux Gazette (http://www.ssc.com/lg/issue26/gm.html) the link:
Linux Multimedia Page  -> http://www.digiserve.com/ar/linux-snd/
should be renamed: Linux MIDI and Sound Page.

Glenn McCarter <[email protected]> wrote to the IRTC Discussion List:

I have uploaded a POV-Ray include file "stereo.inc" to my website.  It can produce a stereoscopic view of any POV-Ray scene.  This was the technique I used in my current IRTC entry, "Dawn Patrol".  The url is http://www.geocities.com/SoHo/Gallery/2006/include.htm.  Feel free to download and experiment.  Non POV-Ray users: you can also take a look at the text file to  understand the approach involved.  Any raytracing program should be able to utilize this technique.  Feedback and comments welcomed.

David R. Heys originally asked the GIMP Discussion List (or possibly the IRTC-L list, I think I may have logged this incorrectly):

It's been more years than I can count since I've been in school learning the various formulae for calculating waves, points within objects, distances, etc. As well, all those old school books are long gone.  Can anyone recommend a good, comprehensive book? I'm looking for something that will summarize the theories and formulae and present it in layman's terms, or as close to layman's terms as possible.

The Schaum's Outline series of books, published by McGraw-Hill, are mostly good no-nonsense material.  Some of them move a little fast if you are learning the material for the first time, but they are excellent for reference and refresher.  If you have a little "mathematical maturity" and take the time to work the problems, you can learn the basics of new subjects with them as well.  The most info-rich ones from a ray tracing perspective are probably Analytic Plane and Solid Geometry, Trigonometry, Matrices, and Mathematical Handbook.  Descriptive Geometry and Projective Geometry have their uses, too.  For rendering specific math, the standard book is Computer Graphics Principles and Practice by Foley, vanDam, et al.  Here you can learn about splines, antialiasing theory and many other useful things.  I also suggest that you visit the nearest vocational college bookstore and look for books on shop trigonometry, particularly compound angles.  Standard math books give this material very short shrift at best.  To design things like polyhedra and complex csg's compound angles are very useful.  If you find a used copy of Bowditch, or some other navigation manual, you can learn a few useful things about sections of spheres as well.  Good luck.

David Robertson <[email protected]> from the Computer Science Department of the University of Otaga wrote:

I enjoyed your summary of X Windows hardware support (or lack thereof).  There is a very interesting web page at
http://parallel.nas.nasa.gov/Parallel/Projects/FOGL/index.html
which gives NASA Ames position regarding Mesa hardware support.  Sadly the page has not been updated since last October, despite the date at the bottom of the page.

Alejandro <[email protected]> wrote:

I read your four article in Linux Journal, now I'm trying to update my version of gimp. I download a file in rpm format, but it doesn't  work. Could you please tell me where to find the las versions of Gimp, and what file I should download?

You're problem, assuming the file you downloaded was a newer version of the GIMP than what you already had on your system, is probably that the version of GIMP you downloaded doesn't work with the GTK libraries you have.  In that case, you need to get a compatible version of the GTK libraries.

Larry S. Marso ([email protected]) wrote to the GIMP User list:

The manual says that Wacom's Artpad is supported, but that patches are required to take advantage of some features, including the pressure sensitive pen.  (The ArtzII is the 6x8 tablet version).

Where are such patches?

If you haven't found them yet, take a look at:  http://www.msc.cornell.edu/~otaylor/gtk-gimp/step-by-step.html

But I had some problems with pressure sensitivity, like random pointer lockups and such, and generally did not like the feel of that much, so although I still use the patched version of gimp -.99.18 - I turned pressure sensitivity off.. I have ArtPad II.

I should mention that I've found the patched 0.99.18 for Wacom ArtZII absolutely flawless (including the pressure sensitivity feature).

Well, I wish it was faster ... and had more options.  But I've never experienced "pointer lockups and such".  The gsumi app available on the same web site provides a bitmap drawing capability at extremely high resolution (the default is 4000x4000) with pressure sensitive drawing (including caligraphic tips).  Great for creating postscript signatures, and also for high resolution drawings suitable for subsequent manipulation by Gimp.

 Offline storage using a Jaz Drive

Last year I attempted to address the problem by installing a 450Mb floppy tape drive on my file server.  Once installed, this worked fairly well with the zftape driver and the taper backup software, but initially I had quite a time getting the zftape driver installed.  From the point of view of cost the floppy tape drive is a good solid solution.  A floppy tape drive currently runs less than $150US.  From the point of view of convenience, well, it takes a long time to backup 1G of data onto a tape drive running off of a floppy controller.  Taper does provide a fairly convenient curses based interface for selecting the files to be backed up or retrieved, but my needs were less administrative.   I simply wanted to copy over a directory tree to some offline media and then clean up that tree.  Later, if I needed them, I wanted to be able to copy them back in.  I'm wasn't quite at the point where offline media management was a real problem - I didn't need special tools for keeping track of what I had on the offline media.  What I needed was a removable hard disk.

Fast forward to this year.  Technology once again has heard the cry of the meek and a flurry of removable hard disk solutions are now hitting the shelves.  One of the first, and currently the most popular if you believe the noise in the trade magazines, is the Iomega Zip drive.  This is a drive with a cartridge that looks somewhat like a fat floppy disk.  The cartridge holds 100Mb of data, good enough for 3 or 4 of my smaller projects or one large project.  The drives are running under $130US (I've seen them as low as $119) and the cartridges are about $20 each, cheaper if bought in bundles of 3 or more.  The drives are available as either parallel or SCSI connected devices.

The problem with this solution is simply size.  100Mb of data can be generated fairly fast using the GIMP - I've had swap files from this tool larger than that.  I also had a hard time finding an external drive.  Most of the drives I could find locally were internal drives.  This was probably just a local distribution or supply problem, but then I didn't look very hard for these drives once I'd decided they simply were too small.

The next step up from this for Iomega is the Jaz drive.  The first versions of these drives, which is what I purchased, hold about 1G of data.  The latest versions will support the old 1G cartridges and the newer 2G cartridges.  An external SCSI version is available so I was able to connect the drive to my recently purchased Adaptec 2940 (which is what I hooked my scanner to) without having to dig into the innards of my hardware.  Again, convenience is a key here - I was willing to pay a little more for ease of use.

There are a number of removable hard drive solutions on the market today, however I wasn't able to find information on support for any of these devices except the Iomega drives.  This information is available at the Jaztool page.  Jaztool is a package for managing the drive, which I'll discuss in a moment.  Strangely, the Jaz Drive Mini-Howto does not appear to be on the Linux Documentation Project pages, although a Mini-Howto for the Zip drive can be found there.

Since the drive is connected to a SCSI controller there aren't any Jaz-specific drivers necessary.  You just need to find a SCSI card with supported drivers.  I chose the Adaptec 2940 because the driver for it (aic7xxx) was a loadable module that was precompiled in the Red Hat 4.2 distribution that I currently use.  In other words, I was able to simply plug the card in, run insmod aic7xxx, and the card was running.  The 2940 has a high density SCSI connector which is the same sort of connector used by the Jaz drive.  I had previously purchased a high density to 25 pin cable converter to connect my 2940 to the UMAX scanner (which has the 25pin connector), so I simply stuck the Jaz driver between the scanner and the adapter.  The Jaz drive comes with a converter, if you need it (the UMAX scanner did not).  Total time for hardware install - about 20 minutes.
 
As mentioned earlier, there is a tool for managing the Jaz drive called Jaztool.  This package provides a software means to eject, write protect or read/write enable, and retrieve drive status.  Password protection is available but not officially supported. The man page gives information on how to use this feature if you wish to give it a try.  Mode 5 (password protected write and read) is not supported by jaztool, even though the Jaz drive supports it.   You cannot access the cartridge that comes with the drive in write mode, so you'll need to use the jaztool program to allow you write access to that cartridge.  The Jaz Drive Mini-Howto explains how to do this quite clearly.  The disk can be mounted as delivered using the VFAT filesystem type, which means that long file names can be used.  This removes the need to reformat disk with native Unix filesystem.  However, the disk that comes packaged with drive is nearly full.  It contains a large number of MS-related tools for DOS, Win3.1, Win95 and WinNT.  Since I didn't need these I simply mounted the drive and used rm -rf * on it to clean it up.  Once I'd done that, I decided to go ahead and just place an ext2 filesystem on the driver.  This is simple enough following the information provided in the Jaz Driver Mini-Howto on the Jaztools page at http://www.cnct.com/~bwillmot/jaztool/.

Speed on the drive is quite good - the Jaz drive has an average of 12ms seek times, compared to the 29ms of the Zip drive.  This provides the sort of file management I was looking for by allowing me to simply copy files to and from the drive and at a speed comparable to my regular disk drives.  Its certainly faster than the floppy tape solution.

As I was writing this article I started to consider if I had gotten my moneys worth.  The Jaz drive runs about $299US for an external SCSI drive, about $199US for internal drives.  Compared to the floppy tape I got about twice the storage space for about twice the price.  At least I thought I had, until I added in the cost of the SCSI card and the media.  The cost for the SCSI card I can significantly reduce by making full use of the 7 devices I can connect to it, but it still ran about $240US.  The media, on the other hand is significantly higher.  Travan 3 tapes (which are what you use with the floppy tape drive) run about $30US or so (I think - its been awhile since I purchased them).  The Jaz cartridges are $125US each!  You can save a little by purchasing them in packs of 3 for about $300US.  The good news here is that recent court rulings have allowed another company (whose name escapes me right now) to sell Zip and Jaz compatible media here in the US.  The result should be a drop in the price of the media over the next 6 months to a year.  The one cartridge I have now will hold me for another couple of months at least.  By then, keeping my fingers crossed, I'll be able to get a 3 pack for $250 or less.

So, adding the Iomega Jaz drive was simple enough.  The information and software provided by Bob Willmot (the Jaztools author) made getting the cartridge running almost a no-brainer.  And I now have over a Gigabyte of external storage that I can access nearly as fast as my regular hard drives.  All things considered, its been one of my better investments.
 
 
   

X Server Update Part II - Metro Link Last month I provided the first part of an update on 3D support available in X Servers and from other places.  I had gotten a number of emails from readers asking where they could find drivers for various 3D video cards.  I also wanted to find out to what extent the X Input Extension is supported.  Since I hadn't done so in the past, I decided to contact the various X server vendors and see what they had to say on the subject.  I sent out a query to the 4 X server vendors I knew of:  Xi Graphics, Metro Link, XFree86 and S.u.S.E.  The query read as follows:  Do you have any information which I may use in my column related to your current or planned support for 3D hardware acceleration (specifically related to OpenGL/Mesa, but not necessarily so)?  What about support for alternative input devices via the X Input Extension.  The GIMP, and its X toolkit Gtk, both make use of X Input if available and I expect many other tools will do so as well in the near future.  Last months article covered 3 vendors, Xi Graphics and XFree86/S.u.S.E, plus the Mesa package.  This month I'll cover Metro Link.  Due to a bit of poor time managment on my part, I wasn't able to cover Metro Link at the same time as the others.  My apologies to all parties for this.  While reading this article please keep in mind that my intent was to simply query for information about X Input and 3D hardware support.  It is not intended for this to be a comparison of the vendors products nor do I offer any editorial on the quality of their products.  I have tried to remove some of the marketing information both from last months article and this months, but I also want to be fair to the respondents and provide as much of the information that they provided that is relevent to the topic.  My first contact with Metro Link was through the assistance of Dirk Hohndel at S.u.S.E., who forwarded my request to Garry M. Paxinos.  Garry was quite helpful and offered information on his own and had Chris Bare contact me with additional information.  Garry first provided me with a few dates:  March 30 - Metro-X 4.3 server release. May - CDE 2.1.10 July - Hardware Accelerated OpenGL This he followed up with a little more detail:  We have a Level II OpenGL source code license from SGI.  This makes it difficult for us to work with GPL'd source.  We have been shipping a software only version of OpenGL since October 8, 1995.  Due to both the competitive nature of this activity and that things might change before release, it is rather difficult for us to have detailed comments on:  Architectural issues. Chip/Board Support Relationships with Chip/Board Vendors (most are under NDA anyway) Relationships with OS vendors   We plan on making our plans public when we get closer to our release.  Count on quite a few press releases.        -Top of next column-		More Musings...   XFPovray
		Current plans are for 3 to 4 specific chip types to be supported in our initial OpenGL hardware release.  We plan on supporting at least two different CPUs in that release.  We've had a policy since our FCS (First Customer Shipment) back in 1995 that all customers will receive a copy of the hardware version when it is released. Garry noted that Metro Link supports 5 different CPUs:  x86, PPC, Alpha, 68k, and Sparc.  He also mentioned that they support multiple operating systems.  Although I didn't mention it last month, both XFree86 and Xi Graphics servers are also available for other operating systems besides Linux.  Not long after my first contact with Garry, Chris Bare provided a more detailed description of what is in the works.  Chris is the engineer responsible for Metro Link's X Input Support.  Metro-X 4.3 (due out in the next month or so as I write this) will include support for dynamically loadable X Input driver modules. The 4.3 release will include drivers for Elo Graphics, Carroll, Micro Touch and Lucas/Deeco touch screens. We are also going to make available a skeleton driver and documentation for anyone interested in supporting devices on their own.  This technology will also be donated to Xfree86 for inclusion in one of their future releases.  Our graphical configuration tool provides a fast and accurate on-screen calibration procedure for any supported touch screen.  Future plans include support for the Wacom tablet as a loadable X Input module and support for 3D input devices like the Space Orb. We are interested in supporting any device there is a reasonably demand for, so if there are any devices your readers have asked about, please let me know. As you can see, Metro Link did not list specific boards which they plan to support.  Neither XFree86 nor Xi specifically mentioned any boards last month.  There appears to be quite of bit of work in the pipe line, however, and according the Garry we should see a flurry of announcements in the relative near term.  Chris does point out some specific input devices that will be supported in the next release, however.  Contact Information  Announcement: comp.os.linux.announce  Web Site: http://www.metrolink.com  Business:  [email protected], which is an autoresponder  Human sales contact:  [email protected]  Garry added:  We do make announcments to c.o.l.a.  And we are working on updating our web site including plans on keeping it up to date. The [email protected] address is our standard public address.    However, that is an autoresponder.   The address [email protected] is referenced in the autoreply and is the 'human' that handles any sales questions manualy.

    The following links are just starting points for finding more information about computer graphics and multimedia in general for Linux systems. If you have some application specific information for me, I'll add them to my other pages or you can contact the maintainer of some other web site. I'll consider adding other general references here, but application or site specific information needs to go into one of the following general references and not listed here.
 

Online Magazines and News sources C|Net Tech News Linux Weekly News Slashdot.org General Web Sites Linux Graphics mini-Howto  Unix Graphics Utilities  Linux Multimedia Page  Some of the Mailing Lists and Newsgroups I keep an eye on and where I get much of the information in this column:  The Gimp User and Gimp Developer Mailing Lists.  The IRTC-L discussion list  comp.graphics.rendering.raytracing  comp.graphics.rendering.renderman  comp.graphics.api.opengl  comp.os.linux.announce

Future Directions

Let me know what you'd like to hear about!