thinman@uunet.UU.NET (01/30/91)
We need a new graphics programming language for Virtual
Reality. It should be a user-pull effort, not a vendor-push
effort. In this article I outline the alternatives with
which we will be faced if we don't move now.
Sources of fear: PHIGS
There is a strong push by the X vendor community to
standardize around PHIGS. This is an old architecture and
(apparently) meets most of the needs of the high-end CAD
market, but doesn't serve other 3D graphics users (i.e.
scientific visualization, virtual reality). PHIGS is a data
list representation standard only. It does not address
putting a complete program into the graphics hardware; it
assumes instead a sufficiently fast linkage between hardware
and application for pleasant interaction speeds.
Sources of fear: PEX
The X Window System will soon be updated to include PHIGS
support (PHIGS Extensions for X). Like everything in X, PEX
is a clumsy poorly-architected kludge. However, it follows
the above profile and it will succeed. X already has
support for animation and stereo viewing, and if there is
enough market interest the big money behind X will pay to
have real-time support kludged into PEX.
Sources of fear: Renderman
Renderman is Pixar's photorealistic rendering system
designed around the Reyes rendering algorithm. They wrote it
for their cinema special effects work. Renderman is a very
nice system for drawing static pictures. With today's Hot
Chips, it can be real-time simply by ignoring 99% of its
graphics control parameters. But, it is proprietary, and
will stay that way. Also, it is merely a graphics library
and thus provides only some of what we need.
Sources of fear: GL
Silicon Graphic's GL is the proprietary control system for
SGI's custom graphics platforms. It is oriented around
hardware-based polygonal rendering. I don't know how
portable it is, but its installed base puts it in the
running. Software-based 3D is simple enough that someone
will write a GL emulator to achieve software portability for
their project. An Australian graphics package called 'VOGLE'
claims to be something like this.
The above systems are the top contenders in the race for a
clumsy and unpleasant Virtual Reality software development
environment.
Lance Norskog
thinman@cup.portal.com