Wednesday, August 13, 2008

Ian Romanick: SIGGRAPH 2008: Day 1

In spite of various travel failure, I managed to get to the Convention
Center by about 7:50AM. Registration opened at 8:00, and I was done
by 8:15...that even includes the time it took me to go back and get
my conference badge. I was originally given someone else's
badge. Oops.

While I was waiting in line, I took a quick peek at /. on my phone.
The story about
developer reaction to OpenGL 3.0
was depressing, at best. I knew
that people were going to be disappointed and upset, but I am a little
surprised at the level of anger that people seem to be expressing. I
can only hope that this is being over exaggerated on /.

One other random thing...I took a bus to downtown (the cab from
downtown to the hotel was $50 yesterday). It was an express
"commuter" bus. The vast majority of the people on it were
30-something / 40-something women. In the front part of the bus there
were 11 women to 1 man (me). I didn't take a census of the rest of
the bus, but the gender distribution appeared to be similarly skewed.
Is it my imagination, or does that seem odd?

I was able to make it to the first paper session. In a lot of
ways, the material in "Factoring Repeated Content Within and Among
Images" reminded me of MPEG macro blocks and motion vectors. Their
technique applies to still images, however. For certain types of
images, they are able to achieve very high quality at very good
compression ratios. In particular, images with very high frequency
information (they used an image of zebras standing in grass) tend to
not work well. The other advantage of their technique is that
decompression can be very easily implemented in a fragment shader.

The interactive
photo tourism
software presented next was, I have to admit, one of the
coolest things I've ever seen. I especially like the ability to use
"community" photos to find paths between sequences of personal photos
to create smooth transitions. The vacation photo slide show will
never be the same!

I was robbed! Michael Abrash wasn't one of the
presenters of the Larrabee paper. We got Larry Seiler instead (no
offense, Larry). That's the end of the bad news. Let me say this
now: Larrabee is going to change everything. I'm still a bit in shock
at how awesome the architecture is. Having worked on Cell, I
believe that Larrabee will be everything that Cell should

Larrabee fixes two significant limitations of the Cell architecture
with respect to implementing a "standard" graphics pipeline.

  • A normal memory architecture. Each core accesses memory via L2
    caches is the same programming model that we've been using forever.
    None of this local storage, software-managed cache nonsense.

  • A hardware texture unit. One of the areas that I was most worried
    about with porting Mesa to Cell was texture mapping. The way that
    textures are addressed and accessed was going to take a lot of
    instructions on Cell. On Larrabee, they just have a freakin' texture
    unit that can, as the Larry said, "support thousands of in-flight
    texture accesses" to hide latency.

Of course, no products, timelines, clock speeds, etc. were
announced. I don't know any of that either, so please don't ask.

I'm filled with a variety of emotions right now. On the one hand
I'm really, really excited for Larrabee and the opportunities
it will bring. I'm also even more disappointed that I already was
about Cell. The window for someone to create an OpenGL implementation
for Cell is now closed. Sure, they could do it, but nobody would
care. Opportunity lost. sigh

The surprise in the last session was the last paper. I wasn't
expecting much from "Real-Time Rendering of Textures With Feature
Curves," but there was some good bits there. Basically, they define a
normal-map using specially encoded Bezier curves for embossing /
engravings. The fragment shader then uses this information to
generate normals that preserve the discontinuity in the "trench" of
the engraving. Using a normal-map texture when there is a
discontinuity can result in some off artifacts in close-up views.
I'll probably mention this work next year in VGP352. I think
it will be a bit beyond the abilities of my students to implement it.
The algorithm has a number of complex details.

The various hair rendering papers were interesting...but
interesting to me in the same way as quantum physics is interesting.
That is, it's good to know that people are working on it, and it's
good to hear about it, but it's not generally useful in my day-to-day

I went and saw most of the expo floor between sessions. It wasn't
really that great. :( About every 4th booth was for an art school.
Of course, The Art Institute was there. There were also a
lot of "3D printer" booths. Yippie. Most disappointing of
all...there weren't any good booth hand-outs. I take that back.
Intel was giving out cool USB hubs, but they wouldn't give me one
because I work there. Fail.

I plan to finish the expo floor tomorrow. I will also try to look
at the rest of the posters. I looked at quite a few today as they are
spread all around the conference center. I've written enough for one
day, so I'll save the poster details for later. There are
some cool the guy doing audio processing and an Nvidia
GPU and audio output from the VGA port.


Complete Story


Sign up for PayPal and start accepting credit card payments instantly.
ILoveTux - howtos and news | About | Contact | TOS | Policy