Fast but not first
The RayCore is not, as the company claims, the world’s first ray-tracing chip. The startup qualifies its claim by calling it the world’s first ray-tracing GPU IP.
The first actual ray-tracing chip was built by Advanced Rendering Technology in Cambridge, UK, in 1995. The company still operates, but gave up its silicon solution about six years ago. Caustic Graphics — now part of Imagination Technologies — started in 2006, building prototype ray-tracing accelerators using FPGAs.
Siliconarts’ goal is to offer an IP block that can be part of an SoC. Caustic is offering a fully function add-in board as a ray-tracing accelerator, while Imagination is offering the IP as part of its library.
Also, like Caustic, Siliconarts offers a blended capability using ray tracing for only certain parts of the scene or image. That saves enormous amounts of time and gives beautiful and (hopefully) physically accurate results.
Ray tracing is one of the great goals of computer graphics and has always been difficult to realize quickly because of its enormous computational load. GPUs are often used, but because of the organization of GPUs, they are not the ideal implementation, even with their thousands of processors.
A ray-tracing image is said to “resolve” or converge, meaning it processes (and processes and processes) until the viewer is satisfied or accepts the image. You may have seen the effect of the scintillation of an image as it builds up all the ray paths.
At Siggraph, AMD showed a technology demo using four high-end Radeon adapter cards running ray tracing. With four cards, the AMD demo could resolve an acceptable image in about two to three seconds, which is pretty fast, but not as fast as the 33 ms that’s required for a 30 frames/second real-time display such as we get in high-definition games today. The desired goal is 16 ms.
Given its performance claims, Siliconarts looks damned interesting. Assuming the startup’s software is clever enough not to launch rays that can’t be seen, a RayCore chip could generate 300 Mrays/second on an HD screen, which would seem to be fast enough.
A ray has to bounce off of several surfaces to create a realistic image. Siliconarts says it will allow up to 15 bounces, which is a lot. Even at that max, you could theoretically realize 30 frames/second, which would be astounding and earth-shaking. Given its location in South Korea, it’s easy to guess which customers Siliconarts targets.
– Jon Peddie is a veteran graphics analyst and principal of Jon Peddie Research in Tiburon, Calif.