Alice 4

A dedicated tablet for running 80s SGI demos!

We decided to make a portable tablet that did nothing but run mid-1980's Silicon Graphics (SGI) demos. The demos were famous. They were pre-installed on all SGI machines for a decade, and they induced instant nostalgia in anyone who had spent time with those wonderful workstations. Both of us had worked at SGI and had used the machines extensively. [...]

The ARM runs Linux and the demos (which we found in source form in a tar file on an ancient FTP site). Brad wrote a replacement IrisGL library, which performs the transformation, clipping, and lighting, and creates an in-memory list of 2D triangles to rasterize. The FPGA rasterizes them, performing color interpolation and Z buffering. The FPGA also scans the frame buffer to the LCD. [...]

The GPU has a rasterization rate of about 50 million Gouraud (color-interpolated) Z-buffered pixels per second. The triangle overhead lets us do almost 2 million (empty) triangles per second. It's hard to compare these numbers to real SGI machines, but we seem to be matching the performance of machines built in the early 1990s.

Previously, previously, previously, previously.

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