Yep, Doom Can Run on Seven-Segment Displays

“Can it run Doom?” is a question that we don’t want to ever die. Originally, it was a practical question; people wanted to know if a computer had the performance necessary to run the game. But even the cheapest computers have been able to run Doom flawlessly for decades now, so the question has evolved into a tongue-in-cheek query about more unconventional hardware. We’re now to a point where almost everything can run Doom, but the question is more interesting when we consider how to display the graphics. As it turns out, you can indeed play Doom on a screen made of seven-segment displays.

A seven-segment display is, as the name implies, a display consisting of seven individual segments (usually short lines). This is the quintessential “digital display,” as it is so common. A single seven-segment display can show the full range of English alphanumeric characters, but it is still quite rudimentary. If, however, you arrange 1,152 seven-segment displays into a 48x24 grid, you can display more complex graphics. By changing the character shown on each individual display (or simply controlling each segment separately), you get something like subpixels and effectively increase that resolution beyond the 48x24 base array. But is that enough to make Doom playable?

A team from Brigham Young University’s Network Enhanced Technologies (NET) Lab developed the Seven Segment Sign, which is the previously described screen made of 1,152 seven-segment displays. A Raspberry Pi 3 Model B+ controls all of those seven-segment displays through daisy-chained MAX7219 serial eight-digit display driver chips via the GPIO pins. The team doesn’t specify the Seven Segment Sign’s max framerate, but it seems to be capable of at least 10FPS.

It seems that their code handles the translation of raster graphics into characters for the seven-segment displays by dividing each display into two “pixels” in each axis. It isn’t clear if they needed to manually define the graphics entities for Doom, but the result is that foreground sprites (like enemies) are distinguishable from the background walls.

While it certainly isn’t an ideal experience, Doom does seem to be playable on the Seven Segment Sign. The graphics are very Spartan — as we would expect — but the game doesn’t need much. Players can see hallways and enemies, which means that they can progress through the game.

The obvious next step is for some brave gamer to set a speed run record in Doom on the Seven Segment Sign.