Want to See Raytracing on the SNES?
Probably not something anyone would ever expect from a console that is about 20 years old, but thanks to one very persistent programmer and a new expansion chip for the Super Nintendo.
The SuperRT chip was the brainchild of one Ben Carter, a software engineer and game developer. Carter, on a whim, used the Super Nintendo to help him learn Verilog and FPGA design. In the process, he also set some restrictions on his own plans, such as trying to emulate the Super FX chip used by a few Super Nintendo games (like Star Fox) and not using any external processing resources.
Carter, who lives in Japan, used a Japanese Super Famicom for this project, which also includes a Pachinko game PCB, sets of shifters, and more technical items to make a frankenstein-looking project that Carter displays upon his home desk.
Cater goes into details on the whole process on his own personal video, uploaded onto his youtube channel. The short version is that the SuperRT chip is able to construct a scene using a specialized command language, which is then executed by parallel execution units on the chip. Carter describes them as CISC processors that perform ray intersection tests, which then cast about four rays per screen pixel, calculating the direct shadows from a directional light source and a single reflection.
All of this is simply a fancy way of saying showcasing what would have been groundbreaking graphics in the early 1990s, with fully 3D shapes casting shadows and reflections across a green, checkered field. The results are actually pretty impressive, considering the age of the hardware.
The whole process on what the SuperRT chip does is actually chronicled on Carter's personal blog for his website, Shironeko Labs. You can read the entire journey Carter went on here, where he goes into detail on aspects such as the ray and execution engine, the converter modules, and more technical jargon that offers a step by step process to creating the video above.