# Fog of war in a 128x128 byte grid

> Odd & Out's fog of war is a 128x128 Uint8Array painted by the characters, read by materials as a texture and by the minimap, and testable in Node.

Canonical page: https://andersonmancini.dev/blog/odd-and-out-fog-of-war-in-128x128-bytes

Published: 2026-10-09 · 1 min read · Tags: shaders, game-dev, three.js, javascript, odd-and-out

The fog of war in [Odd & Out](https://andersonmancini.dev/blog/odd-and-out.md) is a grid of 128 by 128 bytes. Zero means never seen, 255 means seen. That is the whole system, and it serves three readers.

## The grid

Characters paint it as they walk, with a soft-edged circle. It is plain numbers in a `Uint8Array`, with a `version` that bumps on every change, so the texture uploads only when something changed.

## Three readers

- **The materials.** The stylized materials read the grid as a texture and cover what is still unseen with mist.
- **The minimap**, which draws the same data.
- **The scene itself.** A cheap `unseen(x, z)` check asks whether nothing of the 3x3 cells around a point has been seen. The texture is read bilinearly, so a cell next to a seen one is a little seen too, and `unseen` mirrors that. If the mist covers the place entirely, whatever stands there need not be drawn.

Points outside the grid count as unseen.

## Why a byte grid

- It is tiny: 16 KB per level.
- It is testable in Node, with no renderer.
- It is trivially serializable if you want to save what the player discovered.
- A single texture feeds every material through the shared stylized module, so adding a new material that respects the mist is a few lines.

## A pattern

Anything that is "a map of what the game knows" can be this: a small typed array, one version counter, and several consumers. The same idea is behind [the foot analysis](https://andersonmancini.dev/blog/odd-and-out-foot-slide-gait-analysis.md): keep the maths separate from the scene, and tests are cheap.

The project is on its [project page](https://andersonmancini.dev/projects/odd-and-out-game.md).

## Related projects

- [Odd & Out Game](https://andersonmancini.dev/projects/odd-and-out-game.md) — Free co-op alien adventure for the browser