larly, you can build CPUs that have GPU-like
characteristics.” That said, ray tracing slightly
favors current CPUs because those chips were
designed for similar computations as the
physics-based ray engines.
Jerry Bautista, co-director of Intel’s
Tera-scale computing research program,
says, “There’s no computational diff erence
between tracing the path of a bullet and trac-
ing the path of a light ray.” That similarity
could even lead to ray-tracing engines being
recycled as a game’s physics engine, saving
programming and processing power. Bautista
also notes, “General compute engines like a
CPU are pretty well suited to physics kinds
of problems, whereas a GPU is more of a
stream compute engine and probably a little
better suited to... processing triangles at a
high speed.”
Ultimately, hardware companies want soft -
ware developers to have access to the fastest
parts, regardless of renderer. Intel is develop-
ing its massively scalable, multicore Larrabee
architecture. Nvidia is off ering ways for game
developers to run their own rendering code
directly on the video hardware, allowing even
those GPU devices to accelerate ray tracing.
BRIGHT FUTURE
According to Intel, hardware one to two
generations away could render a complete,
real-time scene with ray tracing. But nobody
sees that as the goal. Nvidia’s David Kirk says,
“If you could do all ray tracing, would you? I
don’t think you would. There are many eff ects
that you can do that involve diff use kinds of
lighting—that means soft er, more inter-refl ect-
ed kinds of lighting—that are horrendously
[taxing]... to do with ray tracing.”
The hardware companies want to give
soft ware developers more opportunities to
write their own renderers, mixing and match-
ing methods even within a single scene. Like
the current process in many animated movies,
a rasterizer could sketch in a game scene,
while a ray tracer could add sharp refl ections
and details.
This mix-and-match approach seems to
contradict an API standard, but Microsoft has
already been heading toward this solution.
DirectX even allows game developers to
send programmable shaders directly to the
graphics card, allowing open-ended accelera-
tion regardless of the 3D engine. Chas Boyd,
principal program manager for Windows
Display and Graphics Technology notes, “In
future releases, we will continue to increase
the generality of [Direct3D], and thus off er de-
velopers even more fl exibility in their choice
of rendering methods.”
AUTOPSYSanDisk Sansa e200
Even though it’s two years old, the e200 remains one of the most
feature-rich MP3 players we’ve tested. We pop the top to see what
powers this beast
http://www.maximumpc.com|AUG 08 |MAMAMAXIMXIMXIMXIMUUUUMMPPPCC| 63
SUBMIT YOUR IDEA Ever wonder what the inside of a power supply looks like?
Don’t take a chance on destroying your own rig; instead, let us do the dirty
work. Tell us what we should crack open for a future autopsy by writing to
[email protected].FM TRANSMITTER
Underneath the
e200’s two RAM
modules is the
device’s FM trans-
mitter, a tiny 5x5mm
chip that’s capable
of supporting any
FM reception-band
standard worldwide,
with the correct
firmware.OCTAL BUFFER The LC244A chip
inside the e200 is an octal buffer: It
serves as a bridge between eight dif-
ferent pairs of circuits to keep a single
circuit from being overwhelmed and
affecting the operations of the others.MEMORY These two memory
chips each hold 4GB of flash
memory. The controller for both
rests on the underside of the
raised circuit board, and the
board itself attaches to the e200
using a 40-pin connection.LCD The LCD panel is attached to an
internal controller on the circuit board.
This controller updates the panel’s
graphics using a direct-memory-
access engine that pulls data from any
of the e200’s RAM buffers.PROCESSOR The PP5024 is the
e200’s brain. The applications
processor includes two 32-bit
ARM7TDMI microprocessors that
each feature 100MHz of process-
ing power. The chip also has an
onboard high-speed USB 2.0
controller and audio mixer.