---
title: "Swinging rope: API"
package: "@phaser-ae/rope-swing"
tier: Free
version: 3.0.0-1
released: 2026-10-19
updated: 2026-10-19
description: "A swinging rope for any body on a 2D physics world: a ninja rope that wraps round corners, a grappling hook, or a grapple arm that climbs ledges."
url: https://phaser.io/packs/rope-swing/api
site: Phaser - https://phaser.io
---

# Swinging rope: API

`@phaser-ae/rope-swing` — A swinging rope for a body on a physics-2d world: a ninja rope that wraps round corners as in Worms, a grappling hook, or a grapple arm that mantles.

## The pack

### `ropeSwing`

```ts
function ropeSwing(): Pack<{ ropeSwing: RopeSwingApi }>
```

The `rope-swing` pack: `game.ropeSwing`, swinging ropes for bodies on a physics-2d world.

## Functions

### `createRopeSwing`

```ts
function createRopeSwing(world: World, body: number, options: RopeSwingOptions): RopeSwing
```

Make a rope for a body on a world.

### `segmentEnters`

```ts
function segmentEnters(ax: number, ay: number, bx: number, by: number, s: SwingSurface): number | null
```

Where a segment first enters a convex surface, as a fraction along it, or null when it does not. Edges do not count.

### `surfaceCorners`

```ts
function surfaceCorners(s: SwingSurface): [number, number][]
```

A surface's corners, in order.

## Constants

### `ropeSwingPresets`

```ts
const ropeSwingPresets: { readonly ninja: { readonly range: 420; readonly wrap: true; readonly payOut: true; readonly mantle: 0; readonly reelSpeed: 220; }; readonly grapple: { readonly range: 340; readonly wrap: false; readonly payOut: false; readonly mantle: 64; readonly reelSpeed: 260; }; }
```

The two presets: the Worms ninja rope, and a straight grapple arm with a mantle.

## Types

### `RopeSwing`

```ts
interface RopeSwing
```

The rope, live.

- `readonly attached: boolean` — Whether the rope is hooked.
- `readonly mantling: boolean` — Whether the body is climbing onto a ledge (a mantle); the rope has let go once it is up.
- `fire(target: SwingPoint): { surface: string; x: number; y: number } | null` — Fire at a point: hook the first hookable surface along the line within range. Lets go of any rope first.
- `release(): void` — Let go: the body keeps its momentum.
- `reel(direction: number, dt: number): void` — Reel in (1) or pay out (-1), any amount between, for `dt` seconds.
- `step(dt: number): void` — After each world step: wrap and unwrap, move the bend, set the length.
- `readonly length: number` — The rope's whole length (hook to body, along its bends), or 0 when not hooked.
- `line(): SwingPoint[]` — The rope's line: hook, bends, then the body; empty when not hooked.
- `readonly taut: boolean` — Whether it is pulled straight between its last bend and the body.
- `readonly hook: { surface: string; x: number; y: number } | null` — Where it is hooked, and to what.
- `drain(): RopeSwingEvent[]` — What happened since the last drain, oldest first.

### `RopeSwingApi`

```ts
interface RopeSwingApi
```

What the `rope-swing` pack adds to a game: `game.ropeSwing`.

- `create: typeof createRopeSwing` — Make a rope for a body on a physics-2d world.
- `presets: typeof ropeSwingPresets` — The ninja rope and the grapple arm.

### `RopeSwingEvent`

```ts
type RopeSwingEvent = | { kind: 'hook'; surface: string; x: number; y: number } | { kind: 'miss' } | { kind: 'wrap'; x: number; y: number } | { kind: 'unwrap'; x: number; y: number } | { kind: 'release' } | { kind: 'jam' } | { kind: 'mantle'; surface: string }
```

What happened, for the caller and the presenter.

### `RopeSwingOptions`

```ts
interface RopeSwingOptions
```

How the rope behaves.

- `surfaces: SwingSurface[]` — The surfaces it hooks and wraps round. A surface is hookable unless it says `hookable: false`.
- `range?: number` — The furthest it reaches, and the longest it pays out to. Default 420.
- `shortest?: number` — The shortest it reels in to, beyond its bends. Default 16.
- `reelSpeed?: number` — How fast it reels, units per second. Default 220.
- `wrap?: boolean` — Wrap round corners (the ninja rope). False is a straight arm that lets go when terrain crosses it. Default true.
- `payOut?: boolean` — Allow paying out, past the length it hooked at. Default true.
- `mantle?: number` — Mantle: reeled in to within this of a hook on a ledge's top, or near one of its top corners (within 40 on any face), the body climbs up over the edge onto the top and lets go. Default 0 (off). The grapple preset uses 64: a body pressed against the ledge below its hook is about that far from it.
- `mantleTime?: number` — Seconds a mantle takes. Default 0.3.
- `bends?: number` — The most bends the rope keeps; past it the rope jams and lets go. Default 24.

### `SwingPoint`

```ts
interface SwingPoint
```

A point.

- `x: number` — Across.
- `y: number` — Down.

### `SwingSurface`

```ts
type SwingSurface = | { id: string; kind: 'box'; x: number; y: number; width: number; height: number; hookable?: boolean } | { id: string; kind: 'polygon'; points: ReadonlyArray<readonly [number, number]>; hookable?: boolean }
```

A surface the rope can hook and wrap round: a convex polygon, or a box (centre and size, unturned).

---

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