So, another busy month gone by. I'm still in the throws of pre-shipment testing at work but fortunately my code seems to be pretty stable now. I've even managed to get far enough ahead that I've been able to work at home on other projects while the rest of the gang catches up. To their credit, their stuff was harder to work on than mine. I got to design and write my code from scratch. No legacy code for me.
One of the things I've been working on is getting deeper into the GIMP. If you haven't seen it yet, take a look at the November Linux Journal. The first of a 4 part series I wrote on the GIMP was published in that issue. I also have started to learn much more about how to create interesting effects. If you have some free time and online-money to burn, check out my GIMP Gallery. I've put most of my more interesting images there.
This month I'm going to talk a little about how to use the GIMP to create a frame with a 3D metallic or plastic look. The process turns out to be fairly simply and is one you will probably get to know by heart if you use the GIMP very often.
I'll also cover my notes from SIGGRAPH '97. I wish I could have done this right after I got back when the conference was still fresh in my mind, but things didn't work out that way.
As usual, feel free to send me comments
on any of this.
CurveSoft announces release of FontScope.CurveSoft(tm) is pleased to announce the availability of FontScope(tm): A commercial, high-performance portable rasterizer ibrary for Type 1 scalable fonts sometimes also called PostScript(tm) fonts.
FontScope allows developers and programmers to build Type 1 scalable font support directly into their applications thus roviding a fast, efficient, high quality platform-independent solution to the problem of providing scalable font support.
See http://www.curvesoft.com for further details about the product.
If you have access to a Linux(x86) or a SunOS(SPARC) machine, we strongly suggest downloading the demo program since that allows you to test FontScope on your own Type 1 fonts as well as get an idea of thespeed and quality. If unanswered questions still remain, please email them to email@example.com
A: Check out the VRML update on BUILDER.COM:
Q: Whats the latest news on commercial game development for Linux?
A: There was an important announcement from Crack.com recently. Check out
ldconfig generally looks in /usr/local/lib, along with a few other places, for libraries. To make sure it does, check /etc/ld.so.conf and make sure that directoy is listed there. Check the man pages for ldconfig if you have any further problems.
If ldconfig -p shows gtk is already installed then the other possibility is to add the following to your .profile:
Tethys <firstname.lastname@example.org> wrote in respose to a Musing last month about NetPBM not having JPEG conversion tools:
I did a review of all the Linux scanner information I could find in my Graphics Muse column in March of this year. You can take a look at it starting at the Linux Gazette's (which is the online magazine that carries my Graphics Muse column) table of contents at http://www.ssc.com/lg.
Gregory Gardener <GardenerG@code20nl.npt.nuwc.navy.mil> wrote:
Don't choose a platform, choose a technology: Java and/or VRML. Why? By doing so you remove the need for your end users to be required to have a particular platform to use your software. Second, you can more easily fit into any organization no matter what platforms they might already have.
#3 is a problem. There are only a few VRML browsers for Linux right now and I don't know much abou them. Liquid Reality is one - it requires you have the Java runtime environment installed and working. VRML on non-Linux is actually better supported right now, but that's probably a situation that will be fixed within the next year (again, my guess).
Now, assume you go with these two. Now you can choose your *own* development platform. I'd pick Linux. Why? Because MS is not being very forthcoming about their support of Java - Linux has embraced it quite happily. I'm just getting started with Java development so I can't tell you how to use the tools, but the Java Development Kit (JDK), all the way up to version 1.1.3, has been ported to Linux. There is a commercial Java IDE kit, Vibe, for Linux already.
VRML is like HTML and you can write it using vi or EMACS or whatever text editor you'd like. Eventually there will be WYSIWYG editors for VRML, but for now it shouldn't be difficult to do by hand. In fact, many of the current VRML texts are written from the point of view that you are writing it by hand.
Alternatives: OpenGL/Motif/C. This is the way I'd do it right now simply because I already now Motif and C and OpenGL is something I've been studying off and on for a few months now. I really like OpenGL, but if you use Motif/C your application is less portable across platforms (i.e., it's not very easy to port to MS or Macs). OpenGL has been ported to lots of platforms, but it doesn't provide a windowing toolkit so you have to use it with a toolkit native to your platforms (Motif/X, MS Windows, etc).
Now, this still might not address your problem because "an interactive educational system" can encompass all sorts of display data so it's hard to say if Java/VRML will work for you. What sort of graphics do you need to display? How do they need to be displayed? User Interfaces (UI's) is a big area of study that few people hear about because the hype from the technologies you use for them gets more attention. The problem still exists - which technology do you use? The answer - whatever one you're most comfortable with for now. Eventually, you need to get familiar with Java and VRML.
This month we'll talk about a common trick many people are using in their Web pages today: image rollovers. An image rolllover is an image that changes based on user input. For example, if you look at my GIMP pages (you'll need Netscape 3.x or later for this) you'll see image rollovers in the menus. When you place the mouse over the text for one of the menu items, the Gallery for example, the text background changes to a light blue or cyan color. The text is actually an image, not ordinary HTML text. When you place the mouse over the image it is swapped out for another image, the cyan colored version. Thats a rollover.
Adding rollovers is actually fairly easy. First, you need to make two copies of an image (we're taking a very basic approach to this - you can actually create multiple versions of the image to be displayed based on different types of user input). The first copy is the original, the image to be displayed initially or when no user input is being applied. The second is the image to be swapped in when the user moves the mouse over the original or clicks on the image. Creating these images can be done in any number of ways. Personally, I use the GIMP. It's well-designed for these kind of image processing tasks.
These are called events. There are number of different events that
nor to use with rollovers. The ones of interest are:
|User clicks on an image.
|1.0 (Navigator pre-3.x)
|User moves the mouse over the image
|1.0 (Navigator pre-3.x)
|User moves cursor out from link or image map.
|1.1 (Navigator 3.x)
|User presses a mouse key down but doesn't release it.
|1.2 (Navigator 4.x)
|User releases the mouse button.
|1.2 (Navigator 4.x)
like any other object. Images in a document (documents are HTML pages)
are referenced using names, such as
First, lets look at the image's HTML definition:
A few other things we should note about this bit of HTML:
<!-- Hide script from older browsers
SampleImages = new Array(numitems);
SampleImages = new Image();
SampleImages = new Image();
// Establish the two image objects we want to use.
// Event handler called for onMouseOver event
status = input_status;
document.dog.src = SampleImages.src;
// Event handler called for onMouseOut event
document.dog.src = SampleImages.src;
// End of hidden script -->
The second function, mouseOut(), is called when the mouse is moved out of the image area. It, too, has two lines. The first clears the status bar and the second places the image in the first element of the SampleImages array over the image currently in the object called "dog". In this case, the SampleImages array's first element holds the same image source as the original image displayed in the IMG tag in our HTML source.
A few things to note about the code: I used an array to hold the images I wanted to use for my rollover. In this simple example I could just have easily used
The image object also contains a number of other properties, such as the BORDER width, image HEIGHT and WIDTH, and the VSPACE attribute for setting the vertical space around the image. By not specifying the HEIGHT and WIDTH for the document.dog object in the functions I have assumed the new image has the same dimensions as the old. If this were not the case you might want to update the image dimensions in your functions as well.
Well, that should get you started. Image rollovers are kinda cool to play with and can add a little pizazz to an otherwise drap Web page, but be careful. Like most of the neat toys on the Web, too much of anything can be annoying.
SIGGRAPH 97 NotesFor those that don't know, SIGGRAPH is the yearly conference on computer graphics sponsored by the ACM. To be exact, SIGGRAPH is the Special Interest Group - Graphics of the ACM and the conference is an extension of that, but in the past few years this conference has grown into a major exposition where all the big names in the computer and entertainment industry show their latest wares. This year the conference was held in Los Angeles. It was also my inaguaration into this madhouse.
I should tell you that what follows is not specifically Linux related. I will try to associated what I saw or learned with Linux as much as possible, but in general Linux is not a powerhouse at SIGGRAPH, In fact, with the exception of one technical course and a couple of engineers manning booths at the show, I didn't hear anyone talk about Linux. We have some work ahead of us to get real notice.
For me, SIGGRAPH lasted 4 days, Sunday through Wednesday, even though the conference actually ran for 6 days. I went as my vacation (sick, isn't it) and after 4 days had been run so ragged I decided my last full day would do something quite and peaceful - so I went to Universal Studios. SIGGRAPH, for those who've never been, is non-stop energy drain, both physically and mentally.
My first day there I spent going through lines - at the airport, at the car rental (my god, what a mess), and at the conference registration booths. I had preregistered and so I only needed to pick up my conference materials, but that took about 45 minutes. Having not been to a conference of any kind since a trip to Interop back in 1991, I was a bit disappointed to see no texts provided for the courses. In fact, the courses weren't really courses, they were presentations in front of monster sized audiences. I remember the Interop courses being a bit more personal, more like real classes.
Although I got there late, I did managed to get into the Introductory class on OpenGL that was given by SGI staff members. It was mostly a discussion on basic OpenGL syntax. I did manage to wind up sitting right next to Bruce Peren's office mate at Pixar - a very nice fellow named Jim W. (my notes didn't include his last name - hope he doesn't get made at me). That seemed strange until I found out that Pixar sends just about everyone to SIGGRAPH. A few days later I saw Larry Gritz but didn't get a chance to talk to him. Like most people at SIGGRAPH, he was in a hurry to get somewhere.
The rest of the day I spent wondering around the LA convention center looking for where other classes and events would be held. There was a career center downstairs where people could post resumes and companies posted job positions. Xi Graphics had a posting there, but other than that I didn't see any Linux-related postings. By the time I got back to my hotel it was about 9pm - and I had yet to eat that day. One word of warning to future attendees: take snacks! Finding food can be hard and what you do find can be awful (at least in LA by the convention center) and you will need the enegy! Being a running, I should have brought a few energy bars with me. Well, that's a lesson learned.
The next day I went to the Advanced OpenGL course, also taught by SGI staff. This was a more interesting class to me, since it talked about techniques a bit more than just syntax. There were some good discussions on using environment maps (mapping an image to surface), projecting textures, and billboarding. This last one is a cool technique I wasn't aware of. An image is mapped onto a planar surface and that surface is programmed to always face towards the viewer. It is sort of like taking a photo of a tree, cutting away all of the photo except the tree, and pasting it to a popsicle stick. The stick is then rotated so that the photo of the tree always faces you. It simulates a 3D effect without all the overhead of huge polygon counts for a real tree. This technique works well for scene objects that are in the distance but looses its effect up close. You can see billboarding effects in many games.
Another effect they covered was the creation of fire. They used a noise function along with what are called "quad mappings" to blur regions of the noise. They then added some turbulence and an absolute value
When I got home I went to visit my sister and her kids and watched them play Super Mario Bros on their ... Sega? Anyway, having just returned from SIGGRAPH I could see the effects they talked about in the advanced OpenGL course. It was very enlightening.
One of my reasons for going to the OpenGL courses was to get an idea for how multimedia applications could be built for Linux. An alternative to an OpenGL based multimedia kit would be one based on VRML. I attended the VRML Demo SIG on Monday night and it had some very cool demos using VRML 2.0. If based on CD-ROM this could be a very good cross platform environment for multimedia packages (edutainment, for example). The current drawback is that the demos required 2.0 capable browsers, but there should any number of those showing up in the next year or so. According to CGW (freebie that was dropped at my hotel room - very nice touch), Netscape 4.0 has the SGI Cosmo Player embedded in it now. I haven't been able to get this to work yet, however. Since I have a 2.0 kernel installed now I can try some of the other VRML browsers available. Maybe I'll get to that next month.
|On Tuesday I arrived 1/2 hour early to take the 3D
Animation Workshop. I was about 20th in line of 100 or so, but somehow
managed to miss getting a little blue ticket. Despite the people
at the door having seen me there for 30 minutes waiting (before others
had showed up) I still didn't get in. I was very pissed. This
class was one of my prime reasons for my going to SIGGRAPH. Hint:
if you get in line at SIGGRAPH, make sure you check with the people in
front of you to see if you need to have some special form, ticket, or sacrificial
offering to get in.
My fallback course was the GUI/Multimedia class. There really wasn't much multimedia discussion - mostly it covered how to design GUI intefaces. Lots of design criteria which I'd learned by fire long ago. When they finally did get around to multimedia they talked about the lack of standards and how most applications are reinventing GUI rules. This was my assessment before going to the class, but it was nice to have it reinforced by someone who studies such things for a living.
Next I skipped out to Mark Kilgard's OpenGL w/Windowing systems class. Pretty good stuff. Brian Paul talked about MesaGL a little as well as some portability issues. Both are very nice guys - I chatted with them a bit after the class. One thing Mark mentioned was that there arent' any toolkits specifically built with OpenGL, which makes sense. There is an overhead in creating widgets using OpenGL that would make it unsuitable for most applications. Instead, OpenGL is integrated into applications using some other toolkit, like Motif, XForms, or Tk, using a toolkit specific OpenGL-capable widget.
Later on I stumbled into the Java3D class for a few minutes. Looks interesting but I didn't get too many details. Sun is saying a beta release of a sample implementation of the specification is due out in December of 1997 but the course speakers said they hoped to have it out much sooner. They also expect that since the specification is public and being openly developed that sample implementations from non-Sun sources are likely to show up before the Sun release. Or at least they expect that - they didn't have any information on any specific implementations. At this point I haven't heard of any Java3D announcements from my usual sources.
I talked to a couple of recruiters at the career fair, mostly just to get a feel for what companies are looking for these days. They mentioned that the best way people can avoid getting lost in the crowd of candidates at the fair is to submit resumes based on job postings from the corporate web sites. If you go next year looking for work, check out some of the participating companies job listings before heading to the career fair.
First day of the show for me was Wednesday. It looked more like a cross between a theme park ride and a disco, especially when Intel rolled out their MMX "clean-room dancers". SGI offered a 1/2 hour demo ride with their O2 systems. Cute demo but really didn't give a good feel for what you were really buying. After talking to some of the show staff and taking the demo ride I still don't know exactly what applications come with the stock O2 box. The $4995 price offered to conference participants wasn't bad, however. Certainly compares well with a comparably equipped PC running NT. There is a freeware/shareward CD available for O2 developers according to one of the engineers I talked to, but I didn't see it.
The SGI O2 demo showed me one thing which I had hoped I'd find out from the show: how to create multimedia applications. In fact, after the demo a White Paper was passed out explaining how the demo was put together. Some items, like the networking that allowed real-time texture mapping of live video, are not really possible on Linux boxes with available software. But most of the rest is: OpenGL rendered in Motif widgets was used for the GUI and OpenGL and VRML were used for interactive 3D displays. OpenGL is available commercially and with MesaGL. Motif is available commercially. I'm not certain VRML is available for integration into applications via an API, but animation could be done using MPEG. There are some MPEG API's, such as MpegTV's API. ImageMagick's PlugIn distribution appears to have an MPEG library, but I don't know if it provides a decent enough API for commercial multimedia applications.
After seeing the SGI demo and the VRML SIG demos I've changed my mind about VRML - it's ready for prime time. I wouldn't recommend it for network applications yet, at least not Internet based applications, but for private networks (such as kiosks) or CD-based multimedia applications it could offer some unique possibilities.
Wacom was at the show and a few of the staff didn't get defensive when I brought up Linux (it all depends on how non-abrasively you bring up the subject). They were even quite apologetic about not having any info on which tablets were supported by XFree86. They now have a pad that is actually a full-color flat screen - you simply draw on it like you do with the tablets. Very cool, but currently runs > $2200.
Cosmo Software (new division of SGI) staff were pleasant as well, mentioning that it might be possible to provide someone with the source to port the Cosmo Player to Linux. The player (which plays VRML 2.0 scenes) is free for various other platforms. I guess they just need someone to ask for it and provide some credentials to prove they could do a decent port. Unfortunately, I'm not certain who to talk to about this.
Huge crowds formed around the Apple booth right at the entrance. One demo I caught caused an OS lockup, but for the most part people were quite excited about the products. I don't know much about Mac's so didn't stay long. However, like LInux, Mac is an underdog in the OS world and I can't help but hope they survive.
The one thing about this trip that stood out for me was LA itself.
It was Hot. Outside. Inside. In classes. In the
car. In the hotel. Everywhere. Hot. LA also has an ugly
downtown compared to others I've seen. It also apparently has very
few restaurants anywhere near the Convention Center. A 6 block walk
in Colorado is no big deal, but a 6 block walk in LA in August....*sigh*.
Food was a big problem for me. I hope the same problem doesn't exist
in Orlando next year.
|submitted resumes based on job postings from their web sites.
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:
Let me know what you'd like to hear about!
Graphics Muse #1, November 1996
Graphics Muse #2, December 1996
Graphics Muse #3, January 1997
Graphics Muse #4, February 1997
Graphics Muse #5, March 1997
Graphics Muse #6, April 1997
Graphics Muse #7, May 1997
Graphics Muse #8, June 1997
Graphics Muse #9, July 1997
Graphics Muse #10, August 1997
Graphics Muse #11, October 1997