BALANCING ACT
Clinton Keith, chief technical officer
for Vivendi Software's High Moon Studios, notes that the difficulty in targeting games to different platforms is in matching
the application with the system hardware. High Moon Studios developed the popular Darkwatch game that runs on
both the PlayStation and Xbox platforms.
Keith indicated that bottleneck identification is critical to
enhancing system performance. Once identified, the bottlenecks can be addressed. This means moving where and how
computation is performed, depending on the architecture.
For example, CPU/GPU communication is constrained on
both the PlayStation 3 and Xbox 360. Memory and DMA
bandwidth are often more of an issue than raw computational
performance. That's something developers should consider
when designing the system because it may mean that those
extra cycles can be used for other chores.
Game developers have taken shortcuts and made approximations due to the game platforms' lower-than-necessary performance to provide a computationally accurate real-time gaming
environment. It's only recently that more complex simulation
could be performed.
Backgrounds started as fixed images, grew to sprite objects,
and then became objects with more density and complexity. A
tree may appear lifelike from one angle, but not from another.
Shadows may not be realistic, and so on. Incorporate more algorithms and processing power, and the difference between the
apparent and real instances becomes smaller.
Platforms like the Xbox 360 and PlayStation 3 open up the
possibility of modeling objects like trees. It would use a rule-based system running on an SPE that might otherwise
be idle. Other possibilities include moving computation currently found on
some GPUs to the CPU (or SPE). Taking
advantage of more computation power
may only be part of the issue, though.
Loading, memory, and bandwidth
also come into play, so moving code and
data to different parts of the system may
open up opportunities. It may be possible to reduce the amount of information
that flows between the CPU complex
and GPU, improving overall system efficiency. For example, a CPU can "chew
down" polygons into triangles handled
more efficiently by the GPU. This, in
turn, may free up cycles for other tasks.
Many tasks like the tree simulations
are becoming possible with this new
hardware. High on the list is improved
accuracy, particularly when it comes to
simulating the physics of a game. However, gaming platforms can't take
advantage of new hardware like Ageia's
PhysX chip (see "BFG Technologies And Ageia Make Physics Fun,").
But they can apply their multicore
performance to the task, making them
significantly better than earlier gaming
platforms and most PC-based solutions.
Chips like Ageia's will still have the
edge, just like GPUs have the edge for
graphics, so they may show up in future
gaming platforms.
Another key area affected by the new
hardware is improved scripting language execution and artificial-intelligence support. The latter would allow
flocking algorithms to be used, thus
enhancing the realism.
Even more possibilities open up as
multiplayer games are added to the mix.
Using single systems to coordinate the
other systems involved limits overall
system utilization. Balancing ease of
programming, system response, and system utilization is a complex task that's
made more difficult with the need to
address multithreaded applications running on these platforms.
Keith notes that the potential of the
Xbox 360 and PlayStation 3 is just at
the onset. It will take a copule of years,
plus tools like CodePlay's Sieve, to really see what they can do. Developers at
companies such as High Moon Studios
are already exploring the possibilities
when using up to 32 hardware threads.
In the meantime, expect some stunning
and aggressively intelligent games to
emerge on these platforms.
NEED MORE INFORMATION?
•Ageia
www.ageia.com
•BFG Technologies
www.bfgtech.com
•CodePlay
www.codeplay.com
•IBM
www.ibm.com
•Microsoft
www.microsoft.com
•Sony
www.sony.com
•Vivendi
www.vivendi.com