08 |MAMAMAXIMXIMXIMXIMUUUUMMPPPCC| JUL 08 | http://www.maximumpc.com
QUICKSTART^
THE BEGINNING OF THE MAGAZINE, WHERE ARTICLES ARE SMALLT
he rumor mill is abuzz with specula-
tion that Intel’s upcoming graphics
processor, code-named Larrabee,
will be a ray-tracing powerhouse—but a
98-pound weakling at rasterization, the ren-
dering technique used in current games.
So what the heck is ray tracing? It’s a
rendering technique that traces the path of
light as it travels from the camera through
the pixels in an image plane. An algorithm
tests each ray of light to determine if it
intersects with any objects in the scene
and then takes into account the material
properties of those objects to determine the
color of the pixel it will render. Ray tracing
is capable of producing incredibly photo-
realistic three-dimensional scenes, but it is
massively expensive from a computational
point of view.
“As part of its run-up to the Larrabee
launch, Intel is making a big deal about ray
tracing,” said industry analyst Jon Peddie.
“They’ve been showing ray tracing to IDF
[Intel Developer Forum] attendees, software
developers, analysts, press, and OEMs, try-
ing to build up enthusiasm for the concept.We love ray tracing, but it has been a chal-
lenge to implement and is almost impossible
to do in real time.”
And, in fact, today’s graphic processors,
typifi ed by Nvidia’s GeForce and AMD’s ATI
Radeon HD product lines, are based on an en-
tirely diff erent rendering technique—raster-
ization and shading—and it is this technique
that the games industry currently revolves
around. Rasterization takes a three-dimen-sional scene constructed from polygons and
renders it to the two-dimensional surface of
a monitor; shading describes the process of
changing the color of a polygon
based on its angle to and dis-
tance from a light source.
But since Intel has been
making so much hay about
ray tracing lately, influential
game developers such as
John Carmack (id Software) and Cevat Yerli
(Crytek) have gone on record to play down
the technique’s value to the games indus-
try—at least within the next five years. Intel
is expected to demo Larrabee later this year,
but the product is not scheduled to launch
until 2009 or 2010.
When we asked Intel’s Nick Knupffer
for comment, he seemed taken aback by the
perception that Larrabee would be a weakrasterizing solution: “There would be little
point in us creating a discrete graphics part
if it was not competitive,” said Knupffer.
“We’ve been talking about ray tracing on the
one hand and Larrabee on the other, and I
think people have incorrectly equated the
two. But Intel has focused on DirectX and
OpenGL from day one.”
Knupffer also assured us, however, that
Larrabee would be unlike any solution that
Nvidia and AMD currently have to offer.
“We haven’t disclosed much about the
architecture,” he said, “but it would be safe
to say that it’s a fresh approach to graphics
processing.” Jon Peddie speculates that if
Intel is to support rasterization, “It will be
via a unified memory architecture, because
as far as I know, Larrabee has no graphics
circuitry, and that means it will be intrinsi-
cally limited in performance.”Intel research scientist Daniel Pohl used a ray-tracing technique to create this conversion of Quake 4.
(Image credit: Daniel Pohl, Intel; Quake 4 content by Raven Software.)THE NEWS
Intel is talking up the graphics technology in preparation of its Larrabee
launch, but game developers are having none of it —MICHAEL BROWN
Is Ray Tracing the Next
THE NEWS
Is Ray Tracing the Next
THE NEWS
Big Thing?
LARRABEE WILL BE UNLIKE
ANY SOLUTION THAT
NVIDIA AND AMD CURRENTLY
HAVE TO OFFER.