Doom on the Vectrex Turns a Pixel Shooter Into Vector Line Art
Modder Jason Kopp has Doom running on a Vectrex. Working as ArcadeJason, he built the demo around his Ultimate Vectrex Multicart 2 (UVMC2) cartridge. Doom was originally released in 1993. The Vectrex was released in 1982. Engadget
The Vectrex is the only vector-based home console ever released. It does not render a grid of pixels. Its built-in CRT steers an electron beam to trace lines directly on the screen.
That hardware split defines the build. The UVMC2 handles processing while the Vectrex tube handles display. Audio stays off the console bus entirely. It comes through a separate 3.5mm output on the cartridge. The software side uses an SDK created by modder Daniel Ferrer Guerrero.
The broader context here is the translation between two display models. Doom assumes a pixel buffer, a block of memory that stores the image as colored dots. The Vectrex has no pixel buffer. Every frame must therefore become a sequence of beam movements, with brightness modulation doing the work normally assigned to filled polygons and textures. Walls, enemies and projectiles survive as outlines and wireframe volumes. It plays. It reads as Doom, after the raster image has been reduced to what vectors can express efficiently.
Looking at what this means for system architecture, the Vectrex functions less as a console and more as a vector terminal. Compute lives on the cartridge. Display lives in the console. Audio lives on a separate analog path. For engineers accustomed to SoC integration, where processor, graphics and memory share one chip, that split looks inverted. All of the frame construction happens in the UVMC2, and the 1982 hardware is asked to do the one thing it still does natively, deflect a beam with analog precision. The SDK matters in that arrangement. It abstracts beam control, timing and flicker management so the author can work at the level of geometry rather than deflection voltages.
In my view, the longevity on display is the least surprising part. Vector hardware degrades gracefully because its failure modes are analog and visible, phosphor wear and deflection drift rather than silent bit rot. What is more interesting is the tooling pattern. A cartridge that carries its own processor, plus a community SDK for vector output, turns a closed console into an open display peripheral. I watched my own children treat old consoles as fixed artifacts, machines that play one generation of games and then retire. This approach treats them as input-output devices with a very distinctive renderer attached. For preservation and homebrew, the practical result is clear. Once beam driving is packaged behind an SDK, other pixel-grid games become candidates for the same treatment, subject to line budget and refresh constraints. Not every title will fit. Dense scenes will flicker. Fine text will blur. Those limits are physical. Within them, the Vectrex stops being a curiosity and starts behaving like a constrained vector GPU, one where the constraint is the point.
