---
title: "Arena rooms: API"
package: "@phaser-ae/arena-layout"
tier: Free
version: 3.0.0-1
released: 2026-10-19
updated: 2026-10-19
description: "Seeded rooms for top-down action games, walled grids with obstacles in five styles and every cell reachable, plus the flow fields and wall sliding that bodies need."
url: https://phaser.io/packs/arena-layout/api
site: Phaser - https://phaser.io
---

# Arena rooms: API

`@phaser-ae/arena-layout` — Seeded rooms for top-down action games: walls, obstacles in five styles, all of it connected, a start and an exit, and a flow field to steer by.

## The pack

### `arenaLayout`

```ts
function arenaLayout(): Pack<{ arenaLayout: ArenaLayoutApi }>
```

The `arena-layout` pack: `game.arenaLayout`. Pure functions; no options.

## Helpers

### `arenaField`

```ts
function arenaField(a: ArenaLayout, goal: ArenaPoint): FlowGrid
```

The flow field towards a goal: every open cell knows the way, round the walls.

### `arenaSpawns`

```ts
function arenaSpawns(a: ArenaLayout, count: number, seed: number, minDistance = 180): ArenaPoint[]
```

`count` open cells at least `minDistance` from the start, chosen and ordered by a stream seeded with `seed`.

### `arenaSteer`

```ts
function arenaSteer(field: FlowGrid, p: ArenaPoint, cell = 40): ArenaPoint
```

The way to go from `p` on a flow field: towards the next cell's centre, so a round body clears corners.

### `arenaStyles`

```ts
const arenaStyles: readonly ["pillars", "courtyards", "barricades", "ruins", "galleries"]
```

The obstacle styles.

### `circleFree`

```ts
function circleFree(a: ArenaLayout, p: ArenaPoint, r = 12): boolean
```

True when a circle of radius `r` at `p` touches no wall and is inside the room.

### `generateArena`

```ts
function generateArena(options: ArenaOptions = {}): ArenaLayout
```

Generate a room. Throws, with every fault, on options `validateArena` refuses. Every open cell is reachable from the start.

### `isBlocked`

```ts
function isBlocked(a: ArenaLayout, col: number, row: number): boolean
```

True when the cell is a wall.

### `lineClear`

```ts
function lineClear(a: ArenaLayout, x0: number, y0: number, x1: number, y1: number): boolean
```

True when the straight line between two points crosses no wall cell: an exact walk of every cell the line passes
through, so sight and anything flying along the line agree.

### `moveInArena`

```ts
function moveInArena(a: ArenaLayout, p: ArenaPoint, dx: number, dy: number, r = 12, corner = 0.5): void
```

Move a circle by (dx, dy), sliding along walls rather than stopping at them. Changes `p` in place. Moving straight
at a wall's corner that it overlaps by no more than `corner` of its radius (0.5), it slips round the corner instead
of stopping; 0 turns that off.

### `validateArena`

```ts
function validateArena(options: ArenaOptions = {}): string[]
```

Check a room's options. Empty when one can be generated.

## Types

### `ArenaLayout`

```ts
interface ArenaLayout
```

A generated room.

- `seed: number` — The seed the room was generated from (a whole number, 0 to 2^32 - 1).
- `style: ArenaStyle` — The obstacle style used, whether chosen or picked by seed.
- `cols: number` — Columns across the room, the wall border included.
- `rows: number` — Rows down the room, the wall border included.
- `cell: number` — Side of one square cell, in world units.
- `walls: ArenaRect[]` — Every wall cell, the border included.
- `blocked: number[]` — Wall cells by index (`row * cols + col`), sorted.
- `start: ArenaPoint` — Where the player starts, in world units: the centre of a cell.
- `exit: ArenaPoint` — Where the exit is, in world units: the centre of a cell.
- `open: ArenaPoint[]` — Every open cell's centre, the border excluded.
- `route: ArenaPoint[]` — A shortest route of cell centres from the start to the exit.

### `ArenaLayoutApi`

```ts
interface ArenaLayoutApi
```

What the `arena-layout` pack adds to a game: `game.arenaLayout`.

- `generate: typeof generateArena` — Generate a room.
- `validate: typeof validateArena` — Check a room's options.
- `field: typeof arenaField` — The flow field towards a goal.
- `steer: typeof arenaSteer` — The way to go on a flow field.
- `free: typeof circleFree` — A circle clear of the walls?
- `move: typeof moveInArena` — Move a circle, sliding along walls.
- `spawns: typeof arenaSpawns` — Spawn points away from the start.
- `styles: typeof arenaStyles` — The obstacle styles.

### `ArenaOptions`

```ts
interface ArenaOptions
```

How a room is generated.

- `seed?: number` — The seed. Default 1.
- `cols?: ArenaRange` — Columns, walls included. Default `[12, 15]`.
- `rows?: ArenaRange` — Rows, walls included. Default `[16, 19]`.
- `cell?: number` — A cell's size in world units. Default 40.
- `style?: ArenaStyle` — The obstacle style. Default picked by seed.
- `obstacles?: ArenaRange` — How many obstacles are tried (those that would cut the room off are left out). Default `[9, 14]`.
- `start?: ArenaPlace` — Where the player starts. Default `'bottom'`.
- `exit?: ArenaPlace` — Where the exit is. Default `'top'`, its column picked by seed.
- `clearance?: { start?: number; exit?: number }` — Clear room kept round the start and the exit, in cells. Default 2.75 round the start, 2.25 round the exit.

### `ArenaPlace`

```ts
type ArenaPlace = 'top' | 'bottom' | 'centre' | { col: number; row: number }
```

A place in the room: a side, the middle, or a cell.

### `ArenaPoint`

```ts
interface ArenaPoint
```

A point, in world units.

- `x: number` — Horizontal position in world units, 0 at the room's left edge.
- `y: number` — Vertical position in world units, 0 at the room's top edge; grows downwards.

### `ArenaRange`

```ts
type ArenaRange = number | [number, number]
```

A number, or `[min, max]` picked by seed.

### `ArenaRect`

```ts
interface ArenaRect extends ArenaPoint
```

A wall cell's rectangle.

- `w: number` — Width in world units; one cell.
- `h: number` — Height in world units; one cell.

### `ArenaStyle`

```ts
type ArenaStyle = typeof arenaStyles[number]
```

An obstacle style.

---

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