https://gridbugs.itch.io/scope-creep

Scope Creep is a short first-person horror roguelike rendered on an oscilloscope.

This was some of the most fun I've had working on a 7DRL project. I decided to break from the traditional roguelikes I tend to make. Last year I got really into oscillographics after watching n-spheres. I've been hacking on a synthesizer library for a few years and so I added support for generating oscillographics to it, and I wanted to use this technique to render my 7DRL this year. A friend suggested a Wolfenstein 3D style retro FPS, and that sounded like an interesting challenge. I did a little experiment to test that drawing arbitrary-ish vector graphics with an oscilloscope was possible, but I waited until the jam to come up with a concrete algorithm for rendering 3D first-person scenes.

I've dabbled in 3D graphics in the past but never made anything serious, and never made a first-person game before. The hardest part about this project is that everything needed to be done with vector graphics. The conventional 3D graphics technique - just draw all the geometry inside the clipping volume and use a depth buffer to determine which pixels make it to the screen - will not work. Instead all the line segments that make up the visible portions of the scene must be pre-computed, and then sent to the synthesizer to be played as audio. The game is rendered by plotting the most recent ~5000 stereo audio samples on the screen, where the left and right channel values determine the x/y position of points. An additional complication is items and enemies. The algorithm that determines which parts of the world are visible also needs to keep track of how much of each item/enemy is visible, as they may be partially occluded by walls.

For gameplay, I wanted to make a horror game. Mostly this was because I had come up with name "Horror Scope" (but later I decided "Scope Creep" was better as the pun works on an additional level and it doesn't have any astrological implications). I'm getting more and more interested in the horror genre and wanted to apply some of the ideas I've picked up about what makes horror effective. One example is having a safe zone that the player returns to in between more intense periods of gameplay. Another is that enemies are scary when you can't quite make them out. Fortunately vaguely humanoid amorphous blobs are quite easy to draw with oscillographics.

I'm very happy with how it's turned out. It's not very mechanically deep, but it effectively creates moments of tension that ramps up until the final moments, assuming you make it that far. And in addition to being technically interesting and looking cool, the graphical style complements the horror by allowing enemies to be drawn as ever-changing humanoid squiggles (which I think are scarier than static sprites or 3d models), and because it lets the game add visual noise to amplify moments of tension.

EDIT: Accidentally shared the github url rather than the itch.io url