raphics architectures are in the midst of a
major transition. In the past, these were
specialized architectures designed to support
a single rendering algorithm: the standard
Z buffer. Realtime 3D graphics has now
advanced to the point where the Z-buf-
fer algorithm has serious shortcomings for
generating the next generation of higher-
quality visual effects demanded by games
and other interactive 3D applications. There
is also a desire to use the high computa-
tional capability of graphics architectures
to support collision detection, approximate
physics simulations, scene management, and
simple artificial intelligence. In response to
these forces, graphics architectures are evolving
toward a general-purpose parallel-programming