---
title: "Visibility and line of sight: API"
package: "@phaser-ae/visibility-2d"
tier: Free
version: 3.0.0-4
released: 2026-10-14
updated: 2026-10-20
description: "Answers the three questions a 2D game asks of its walls, what can be seen from here, can this point see that one, and what does a ray hit first."
url: https://phaser.io/packs/visibility-2d/api
site: Phaser - https://phaser.io
---

# Visibility and line of sight: API

`@phaser-ae/visibility-2d` — Visibility polygons, line-of-sight checks and raycasts against wall segments. Headless. game.visibility.create().

## The pack

### `visibility2d`

```ts
function visibility2d(): Pack<{ visibility: Visibility2dApi }>
```

The 2D visibility pack: visibility polygons, line of sight and raycasts against wall segments. Headless, no
columns, no passes — a factory for `Visibility2d` sets. The lighting pack uses the same class for its shadows.

## Classes

### `Visibility2d`

```ts
class Visibility2d
```

A set of wall segments and the queries on them: the VISIBILITY POLYGON from a point (rays to every segment
corner ±ε, the nearest hit each, sorted by angle — the classic fan), line of sight between two points, and a
raycast. Pure geometry, no kernel state: `game.visibility.create()` makes one; the lighting pack keeps one as
`game.lights.occluders`.

- `readonly segments: Segment[]` — The occluders. Add with `addSegment/addRect/addPoly`, or mutate a returned Segment to move a wall.
- `constructor(bounds?: { x: number; y: number; w: number; h: number })` — Optional starting bounds (see `setBounds`).
- `setBounds(x: number, y: number, w: number, h: number): void` — A rectangle rays always stop at, so a polygon in an open world is finite. The lighting pack sets it to the camera's view each frame.
- `addSegment(x1: number, y1: number, x2: number, y2: number): Segment` — Add one wall. Returns it, to move or to find and remove later.
- `addRect(x: number, y: number, w: number, h: number): void` — Add the four walls of an axis-aligned rectangle (top-left x, y; width, height).
- `addPoly(points: ReadonlyArray<Vec2> | ReadonlyArray<number>, closed = true): void` — Add a polyline's edges, as points or a flat [x, y, x, y…] list; `closed` (default true) joins the last point to the first.
- `remove(s: Segment): void` — Remove one segment returned by `addSegment`; unknown segments are ignored.
- `clear(): void` — Drop every segment (the bounds stay).
- `visibility(lx: number, ly: number, maxDist = Infinity): Vec2[]` — The visibility polygon from (lx, ly): its vertices in angle order, ready to fan into triangles. `maxDist` caps the rays (a light's radius) and culls segments beyond it. Empty when nothing bounds the rays (no segments in reach, no bounds, no maxDist).
- `canSee(ax: number, ay: number, bx: number, by: number, maxDist = Infinity): boolean` — True when the straight line from a to b crosses no segment (bounds ignored) and is within `maxDist`.
- `raycast(ox: number, oy: number, dirX: number, dirY: number, maxDist = Infinity): RayHit | null` — The nearest segment (or bounds) hit by a ray from (ox, oy) along (dirX, dirY), within `maxDist`; null when nothing is hit.

## Types

### `RayHit`

```ts
interface RayHit
```

What `raycast` returns when the ray hits something.

- `x: number` — Hit point x.
- `y: number` — Hit point y.
- `dist: number` — Distance from the origin along the ray.

### `Segment`

```ts
interface Segment
```

One occluding wall segment, from (x1, y1) to (x2, y2). Mutate the fields to move it.

- `x1: number` — Start x.
- `y1: number` — Start y.
- `x2: number` — End x.
- `y2: number` — End y.

### `Vec2`

```ts
interface Vec2
```

A point in world units.

- `x: number` — x, world units.
- `y: number` — y, world units.

### `Visibility2dApi`

```ts
interface Visibility2dApi
```

`game.visibility`.

- `create(bounds?: { x: number; y: number; w: number; h: number }): Visibility2d` — A fresh, empty occluder set. Not scene-scoped: the game holds it (drop it when the level ends).

---

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