Crossing the threshold
Graphics chips could get close to rendering "anything," at least. Peercy noted two capabilities needed in graphics hardware in order to run nearly all general shading routines with relative ease: higher-precision data types and what he called "texture pixel." The latter of those capabilities arrived with the Radeon 8500 in the form of pixel shaders capable of dependent texture operations. NVIDIA extended its pixel shaders to incorporate this capability in the GeForce4 Ti chip, and newer cards like Matrox's Parhelia have this feature, as well.

The former of those capabilities is set to arrive on the scene with ATI's R300—now powering the Radeon 9700—and NVIDIA's forthcoming chip, code-named NV30. Both of these next-gen chips can process 128-bit floating-point datatypes for increased precision and extended dynamic range. Extended dynamic range will allow lifelike representations of subtle lighting effects and soft color tones. Increased precision will allow the chips to render complex shader techniques without accumulating error through multiple rendering passes. (Color artifacting with 32-bit color isn't so bad through one or two rendering passes, but it becomes a real problem after the same data makes 10 to 20 passes through the pipeline.)

Some recently released chips, like Matrox's Parhelia and 3DLabs' P10, offer increased color precision by assigning 10 bits to each red, green, and blue color channel at the expense of precision in the alpha (transparency) channel. These solutions are sometimes helpful, but they can't match true floating-point datatypes. The inability to represent fractions makes some types of math difficult, and quantization error is a problem. Plus, some applications will want to use the alpha channel, and two bits of alpha is hardly enough.

So ATI's R300 and NVIDIA's NV30 will comprise the first generation of dedicated graphics chips capable of cinematic quality shading. They won't be capable of rendering all of the best effects seen in recent movies with all of the detail in each scene in real time, but they should be able to deliver some exceptionally compelling graphics in real time. Gamers had better hold on to their seats once games that use these chips arrive. And these chips will challenge entire banks of servers by rendering production-quality frames at near-real-time speeds. Graphics guru John Carmack's recent Slashdot post on the subject anticipates replacing entire render farms with graphics cards within 12 months:

Note that this doesn't mean that technical directors at the film studios will have to learn a new language -- there will be translators that will go from existing languages. Instead of sending their RIB code to the renderfarm, you will send it to a program that decomposes it for hardware acceleration. They will return image files just like everyone is used to.

Multi chip and multi card solutions are also coming, meaning that you will be able to fit more frame rendering power in a single tower case than Pixar's entire rendering farm. Next year.

I had originally estimated that it would take a few years for the tools to mature to the point that they would actually be used in production work, but some companies have done some very smart things, and I expect that production frames will be rendered on PC graphics cards before the end of next year. It will be for TV first, but it will show up in film eventually.

ATI has already stated that its R300 chip can work in parallel configurations using as many as 256 chips.

Not only that, but artists and animators should be able to preview effects and animation sequences instantaneously, tweaking and fiddling with them in real time on a workstation equipped with a single or multi-chip AGP card.

So Pixar had better be ready to receive its carton of graphics cards. Only two years after Tom Duff laughed out loud at NVIDIA's ambitions, graphics chip makers are on the brink of reaching their goal of producing Hollywood-class graphics on a chip.

What's ahead
With this set of advances, we can see the way forward in graphics hardware more clearly than before. As ATI's Rick Bergman noted at the Radeon 9700 launch, what comes next will largely build on the foundation established by this new generation of chips. Future chips will be faster versions of what we have now, and the additional power will make ever more complex scenes and rendering techniques possible in real time. Newer generations of chips will further clean up the rendering pipeline, bringing more mathematical precision to any remaining pockets of lower precision. And although most of the advancements we've talked about are related primarily to pixel shading, vertex processing power will continue to mushroom, as well.

In fact, Peercy's prescient insights about multi-pass rendering's possibilities may prove to be only a way station to the future of real-time graphics. Already, graphics chip makers have introduced programmability into their chips in the form of pixel and vertex shaders, making rendering in multiple passes less necessary. The move toward general programmability on graphics chips has begun in earnest.

But before I get too far into such things, we should turn our attention to the next-gen graphics chips arriving soon and see more precisely how they fit into the picture.