---
title: "Fog of war: API"
package: "@phaser-ae/fog"
tier: Free
version: 3.0.0-3
released: 2026-10-14
updated: 2026-10-19
description: "Tile-grid fog of war with shadowcast lights, a brightness for every cell and a memory of what the player has already seen."
url: https://phaser.io/packs/fog/api
site: Phaser - https://phaser.io
---

# Fog of war: API

`@phaser-ae/fog` — A tile-grid fog of war: shadowcast lights over opaque cells, a brightness per cell, and a memory of what was seen. Headless. game.fog.create().

## The pack

### `fog`

```ts
function fog(): Pack<{ fog: FogApi }>
```

The fog-of-war pack: a factory for `FogGrid`s. Headless, no columns, no passes.

## Classes

### `FogGrid`

```ts
class FogGrid
```

A fog-of-war grid: recursive shadowcasting over opaque cells from any number of lights, a brightness per
cell, and a memory of what has been seen. Headless; the game draws it (a dark tile per cell by `state()`,
or an alpha from `lightAt()`).

- `readonly cols: number` — Columns.
- `readonly rows: number` — Rows.
- `falloff: FogFalloff` — Default falloff for lights without their own.
- `memory: boolean` — Remember explored cells.
- `readonly opaque: Uint8Array` — 1 where a cell blocks light; cols × rows, row-major.
- `readonly light: Float32Array` — Brightness 0..1 per cell after `compute()`.
- `readonly explored: Uint8Array` — 1 where a cell has ever been lit (when `memory`).
- `readonly lights: FogLight[]` — The lights. `addLight` appends; mutate and `compute()`.
- `constructor(opts: FogGridOptions)` — Build an empty, dark grid. Sizes are floored and at least 1.
- `index(col: number, row: number): number` — Row-major index of a cell.
- `inBounds(col: number, row: number): boolean` — True inside the grid.
- `cellAt(x: number, y: number, cellSize = 1, originX = 0, originY = 0): Cell | null` — The cell under a world point, given the cell size and the grid's origin; null outside.
- `isOpaque(col: number, row: number): boolean` — True when the cell blocks light (outside the grid counts as opaque).
- `setOpaque(col: number, row: number, on: boolean): void` — Make a cell a wall or not.
- `clearOpaque(): void` — Every cell open.
- `blockFrom(grid: ReadonlyArray<ReadonlyArray<number>>, wallValue = 1): void` — Set the walls from a 2D array (rows of values), treating `wallValue` as opaque.
- `addLight(col: number, row: number, radius: number, opts: { intensity?: number; falloff?: FogFalloff } = {}): FogLight` — Add a light; returns it to move later. Intensity default 1.
- `removeLight(src: FogLight): void` — Remove one light; unknown lights are ignored.
- `clearLights(): void` — Remove every light.
- `compute(): void` — Recompute `light` from every light (the max where they overlap) and extend `explored`. Call after anything moved.
- `lightAt(col: number, row: number): number` — Brightness 0..1 at a cell; 0 outside.
- `isVisible(col: number, row: number): boolean` — True when lit now.
- `isExplored(col: number, row: number): boolean` — True when lit at some point (with `memory`).
- `state(col: number, row: number): FogState` — The three-way state of a cell.
- `canSee(fromCol: number, fromRow: number, toCol: number, toRow: number, range = Infinity): boolean` — Bresenham line of sight between two cells through open cells, within `range` cells.
- `reveal(col: number, row: number, radius: number): void` — Mark everything a light at (col, row) with `radius` would reach as explored, without changing `light`.
- `revealAll(): void` — Everything explored (a map reveal).
- `resetMemory(): void` — Nothing explored.

## Types

### `Cell`

```ts
interface Cell
```

A grid cell.

- `col: number` — Column.
- `row: number` — Row.

### `FogApi`

```ts
interface FogApi
```

`game.fog`.

- `create(opts: FogGridOptions): FogGrid` — A fresh grid. Not scene-scoped: the game holds it.

### `FogFalloff`

```ts
type FogFalloff = 'none' | 'linear' | 'smooth' | 'quadratic'
```

How a light's brightness falls with distance, as a fraction 0..1 of its radius.

### `FogGridOptions`

```ts
interface FogGridOptions
```

What `create` takes.

- `cols: number` — Columns.
- `rows: number` — Rows.
- `falloff?: FogFalloff` — Default falloff. Default 'smooth'.
- `memory?: boolean` — Remember lit cells as 'explored' once the light moves on. Default true.

### `FogLight`

```ts
interface FogLight
```

A light source on the grid. Mutate `col`/`row` to move it, then `compute()`.

- `col: number` — Cell column.
- `row: number` — Cell row.
- `radius: number` — Reach in cells.
- `intensity: number` — Brightness at the source, 0..1.
- `falloff?: FogFalloff` — This light's falloff; the grid's when omitted.

### `FogState`

```ts
type FogState = 'unseen' | 'explored' | 'visible'
```

A cell's state: never lit, lit once and remembered, or lit now.

---

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