RE: [Axiom-developer] axiom graphics and porting

[Page, Bill]

In the context of this discussion let me recall a much earlier
email from Mike Dewar:

http://lists.gnu.org/archive/html/axiom-developer/2002-11/msg00151.html

Re: [Axiom-developer] Windows front end
Subject:        Re: [Axiom-developer] Windows front end
Date:   Fri, 29 Nov 2002 10:24:19 +0000

On Thu, Nov 28, 2002 at 10:35:20AM -0500, Tim Daly wrote:
<snip> 
> Mike Dewar wrote:
> > 1. Graphics: On Unix this is done with a combination of bespoke
> > Axiom data structures and some pretty convoluted X-Windows code.
> > On Windows we added facilities to create OpenInventor data structures
> > (OpenInventor is the basis for VRML - the virtual reality markup
> > language).  The Inventor geometries were then exported to a little
> > application we wrote based on the standard SceneViewer application
> > you get with many OpenInventor toolkits.  The results were definitely
> > superior to the Unix version.
> 
> Is the "little application" in the code we have? If not, would NAG
> be willing to share it?

No and no :-(  As I said its based on something which was part of the
Inventor toolkit we were using and that is a commercial product which
we were licensing.  However it shouldn't be too difficult to find a
free VRML viewer and adapt that.  

> I'm happy to hear that work was done to make the graphics more open.
> One of the stated goals on the homepage is to "give away" the graphics.
> I was planning to enhance the abilities of some other open source
> product (like GNUPlot) with the facilities available in Axiom. That
> way they gain with new function and we gain because we don't have to
> support the graphics any more.

I think we looked at GNUPlot and decided it wasn't good enough because
it lacked many of the features for manipulating 3D images that were in
the Unix version.  Using Open Inventor/VRML means you can export images
to industrial-strength visualisation packages which was important to us.
After we released Axiom under Windows, Maple moved their graphics onto
OpenGL (the toolkit Open Inventor is built on) so we're not the only
people who think that this is a good approach :-) Of course GNUplot has
probably come a long way since we looked at it and may be suitable for
your needs, but I doubt its as good as Mathematica and Maple's
offerings.

> The graphics facility is useful and necessary but the expertise
> needed to do it right is a whole other field of research. Scott
> Morrison did the graphics and he's no longer following computer
> algebra.

Don't underestimate the importance of visualisation and computer
algebra.  Over the years I've met a number of users who chose Axiom
primarily because of its graphics.
 
> If you happen to have some useful web and/or book references I'd
> appreciate it if you mention them to the group.

http://www.web3d.org/vrml/vrml.htm seems to be a good place to start
investigating VRML.

...

-----------

In the meantime VRML has evolved into X3D. See

http://www.web3d.org/x3d/overview.html

And OpenInventor is now available as open source

http://oss.sgi.com/projects/inventor

and is apparently also available for native Windows

http://www.studierstube.org/openinventor

I think the concepts discussed here by Tim and Mike still apply,
maybe even more so. If Axiom graphics needs to be re-written
and/or modified to be more portable between linux and Windows
then I definitely think that consideration should be given
to compatibility with the web as well. X3D/VRML seems to me
to be a good approach. This looks especially attractive in
the context of the MathAction website since it would allow
Axiom graphics to be served in a compatible manner between
the desktop and a remote graphics browser. This is also
obviously important for the Doyen project.

It seems quite clear that what we called "computer graphics"
yesterday is just going to be some limited form of virtual
reality display in the near future. From my point of view,
if we have to invest significant effort in re-developing
things, then we should aim as high as is practical. Otherwise
it would be better I think to just take the shorter path
(involving Cygwin as described previously).

As far as I can tell right now the only cross-platform
desktop X3G browser is dependent on java

http://www.xj3d.org

but that might change in the next few months as more
options become available.

In any case, perhaps we should seriously consider trying
to recover NAG's work on OpenInventor in Axiom graphics.

Regards,
Bill Page.