Michael Jones (mtj++at++babar)
Tue, 27 Dec 1994 17:27:30 -0800
:Yeah, IMHO, the Performer team blew it big time by not giving Inventor better
:coverage.
It was my decision, not the team's. At the time of our release I felt that it
was necessary to support both IRIX 4.0.5 and 5.x customers with our
IRIS Performer 1.2 product. Since the version of IRIS Inventor for 4.0.5
lacks the key feature required for a successful Inventor-format loader,
I just gave up on a complete solution and hacked out the loader that you
love to hate one afternoon a week before our release.
The key feature is the ability to ask Inventor to give back the polygons
it would draw at any node. This is required to allow for importation of
procedural objects such as cones and spline-edged text. Without it we'd
have to implement all of Inventor just to provide file import capability.
Since the next release of IRIS Performer will be based on IRIX 5.3, we
can now take advantage of this feature of IRIS Inventor 2.0 to bring
you a fully working loader that reads *all* Inventor files (binary and
ASCII) and handles complexity-nodes, NURB surfaces, and the other
"hard to translate just by looking at the file format" nodes correctly.
It's hard for me to agree that this course of action was a big mistake
since the number of Inventor users seemed very small at the time and
our desire to have identical capability in the IRIX 4.0.5 and 5.x versions
of Performer was so very great.
If its any consolation, we're working hard on robust IRIS Inventor
support at this time. In fact, now that Silicon Studio has selected IRIS
Performer for it's entertainment authoring developments and the IRIS
Inventor format for the external representation, we have a very focused
effort to support both the complete format and the full set of Inventor
widgets and manipulators within the Performer scene-graph. Anybody
who uses either Inventor or Performer is sure to benefit from these
current development efforts.
:I read in the FAQ that a more complete Inventor reader was to be
:distributed through the info-performer mailing list "at a future time." I
guess
:the future hasn't happened yet. In the mean time, I've pulled a copy of pfiv.c
:out of /usr/src/Performer/... and I'm trying to hack out my own LoadIv()
:function.
The future was delayed slightly as we strove to make the new loader more
efficient. The first version, though complete in it's support, lacked automatic
sharing of textures and materials throughout the scene-graph, reducing
performance to about 2x that of IRIS Inventor. Now that we've put more
effort into the loader and it's ingenuity about sharing geostates and the
geostate components, we've been able to considerably improve that ratio
closer to the IRIS Performer efficiency with other file formats, such as
Wavefront, OpenFlight, and Designer's Workbench.
We're working hard to get the new loader out via the mailing list this
week, so check your email for the latest info. Remember though that this
will only work for those IRIS Performer 1.2 users who have upgraded
to IRIX 5.x -- IRIX 4.0.5 users will never have full Inventor import
capability.
:That's another thing. I've been reading Gavin Bell's postings in
:comp.sys.sgi.graphics. He is asking if any Inventor users would be upset if
:Inventor's C API were to disappear in a future (the next?) release. I guess
:we'd better hope the Performer team is moving to C++ or we are really going to
:be left out in the cold.
IRIS Performer's written in C, C++, and MIPS Assembler. The utility
code and all other source is distributed in C for broadest usability. The
new Inventor loader is in both C and C++, so you'll need the C++
compiler if you want to recompile it. We'll be distributing the object code
DSO as well as the source though, so you can use it without having the
C++ compiler if you don't want to change it.
We will be compiling all of Performer with the C++ compiler in the next
release but plan to keep the utility library source in C. Any comments on
this plan? What would you prefer?
:Thanks again.
:Thom
Thank you for your postings. We try to serve each of our customers well
and we slip from time to time. Thanks for being patient with us on the
Inventor-loader issue.
--Be seeing you, Phone:415.390.1455 Fax:415.390.2658 M/S:8U-590 Michael T. Jones Silicon Graphics, Advanced Graphics Division mtj++at++sgi.com 2011 N. Shoreline Blvd., Mtn. View, CA 94039-7311
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