---
title: "Rooftop Runner 2D: API"
package: "@phaser-ae/rooftop-runner-2d"
tier: Pro
version: 3.0.0-3
released: 2026-10-14
updated: 2026-10-19
description: "Forward-only rooftop running with tap-or-hold jumps, rising speed and obstacles, on seeded courses that come with a replay proving they can be cleared, finite or streamed without end."
url: https://phaser.io/packs/rooftop-runner-2d/api
site: Phaser - https://phaser.io
---

# Rooftop Runner 2D: API

`@phaser-ae/rooftop-runner-2d` — Forward-only rooftop survival with variable jumps, increasing speed, obstacle impacts and certified finite or streamed courses.

## The pack

### `rooftopRunner2d`

```ts
function rooftopRunner2d():Pack<{rooftopRunner2d:typeof rules}>
```

Install renderer-independent runner rules and generation.

## Helpers

### `createRooftop`

```ts
function createRooftop(config: RooftopConfig)
```

Start a run on `config`, validated and copied. The result has `config`, `state` (a copy), `tick(input?)` (one 1/60 s
tick; does nothing once won or lost; returns the state), `reset()`, `rewind(frames = 120)`, `recording()` (the inputs
played up to now) and `replay(frames)` (plays a `RooftopFrame[]`; at most 24000 ticks). Throws on an invalid config.

### `createRooftopStream`

```ts
function createRooftopStream(options: RooftopOptions)
```

Start an endless run. It begins like a 6-roof `generateRooftop` course, and each time the runner stands on the
last roof it appends a certified 5-roof stretch. The result has `state` (the runner's state plus `chunk`, the
stretches appended), `config` (the terrain still kept), `tick(input?)`, `reset()`, `rewind(frames = 120)`,
`recording()` and `solveAhead()` (an input route to win the stretch ahead, or null).

### `generateRooftop`

```ts
function generateRooftop(options: RooftopOptions): RooftopLevel
```

Make a course for `options` and prove it winnable by planning and replaying a solution. Throws on invalid options, or if no candidate course can be solved within 100 tries.

### `planRooftop`

```ts
function planRooftop(config: RooftopConfig, maxFrames = 12000, start?: RooftopState): RooftopFrame[] | null
```

Searches takeoff time AND hold length at the actual incoming speed for each landing.

### `ROOFTOP_STEP`

```ts
const ROOFTOP_STEP: number
```

Seconds in one fixed tick of the rules: 1/60.

### `rooftopStyles`

```ts
const rooftopStyles: readonly ["skyline", "girders", "obstacles", "mixed"]
```

Every `RooftopStyle`, for menus and validation.

### `validateRooftop`

```ts
function validateRooftop(c: RooftopConfig)
```

Check a course. Throws on the first fault: a number out of range or not finite, a roof or obstacle with a duplicate id, a bad shape or an unknown kind.

## Types

### `Roof`

```ts
type Roof = { … }
```

A roof the runner can land on, in world units with x to the right and y down.

- `id: string` — Unique among the config's roofs and obstacles; `RooftopState.support` names it while the runner stands on it.
- `left: number` — The x of the roof's left edge.
- `right: number` — The x of the roof's right edge; at least 30 units past `left`.
- `top: number` — The y of the walking surface; a larger y is lower.
- `kind: 'building' | 'girder' | 'tower'` — `'building'` and `'tower'` have solid sides that end the run if struck below the surface; a `'girder'`'s side is only 18 units deep.

### `RoofObstacle`

```ts
type RoofObstacle = { … }
```

Something on or above a roof that the runner must clear, in world units.

- `id: string` — Unique among the config's roofs and obstacles; a clipped crate's id is listed in `RooftopState.hits`.
- `x: number` — The x of the obstacle's centre.
- `y: number` — The y of the obstacle's centre.
- `w: number` — Width, at least 1.
- `h: number` — Height, at least 1.
- `kind: 'crate' | 'hazard' | 'ceiling'` — `'crate'` is clipped once and costs speed; `'hazard'` and `'ceiling'` (an overhead beam) end the run on contact.

### `Rooftop`

```ts
type Rooftop = ReturnType<typeof createRooftop>
```

A run made by `createRooftop`.

### `RooftopConfig`

```ts
type RooftopConfig = { … }
```

A finite course and the runner's motor, in world units and seconds. `validateRooftop` states the accepted ranges.

- `roofs: Roof[]` — The roofs, 1 to 200.
- `obstacles: RoofObstacle[]` — The obstacles, 0 to 300.
- `start: { /** The x of the centre. */ x: number; /** The y of the centre; standing on a roof at \`top\` it is \`top - 13\`. */ y: number; }` — Where the runner's 16 by 26 body starts: its centre.
- `finish: number` — The x the runner must reach while on a roof to win.
- `speed: number` — The starting horizontal speed, in units a second; 100 to 700.
- `maxSpeed: number` — The horizontal speed the run accelerates to, in units a second; from `speed` up to 900.
- `acceleration: number` — Horizontal acceleration, in units a second squared; 0 to 100.
- `gravity: number` — Downward acceleration, in units a second squared; 400 to 1800.
- `jumpSpeed: number` — Upward speed a jump starts with, in units a second; 200 to 700.
- `deathY: number` — Falling below this y loses the run.

### `RooftopFrame`

```ts
type RooftopFrame = { … }
```

An input held for a run of ticks: a replay or a solution is a list of these.

- `input: RooftopInput` — The input applied on every tick of the run.
- `frames: number` — How many consecutive ticks of 1/60 s the input is held; a whole number from 1 to 24000.

### `RooftopInput`

```ts
type RooftopInput = { … }
```

One tick's input.

- `jump?: boolean` — Whether the jump button is held this tick: a press starts a jump, releasing while rising cuts it short. Anything but a boolean throws.

### `RooftopLevel`

```ts
type RooftopLevel = { … }
```

A generated course with the input route that proves it can be won.

- `seed: number` — The seed it was made from.
- `parameters: Required<RooftopOptions>` — The options with every default filled in.
- `config: RooftopConfig` — The course, ready for `createRooftop`.
- `solution: RooftopFrame[]` — An input route, compressed into runs of ticks, that replays to a win.
- `metrics: { /** Ticks the solution takes to reach the finish. */ frames: number; /** Jumps the solution makes. */ jumps: number; /** Which candidate layout (counting from 0) was the first that could be solved. */ attempt: number; /** The roofs and obstacles as JSON: equal signatures mean equal layouts. */ signature: string; /** Roofs in the course. */ roofs: number; }` — Facts about the solved course.

### `RooftopOptions`

```ts
type RooftopOptions = { … }
```

What `generateRooftop` takes.

- `seed: number` — Unsigned 32-bit integer; the same seed and options make the same course.
- `difficulty?: Difficulty` — `'easy'`, `'medium'`, `'hard'` or `'very-hard'`; default `'medium'`. Harder is faster, with wider gaps and bigger height changes.
- `style?: RooftopStyle` — The kind of course; default `'mixed'`.
- `roofs?: number` — Roofs in the course, 3 to 30; default 6 plus 2 for each difficulty step plus the seed modulo 3.

### `RooftopState`

```ts
type RooftopState = { … }
```

Where the runner is and how the run stands; plain data, copied on every read.

- `x: number` — The x of the body's centre, in world units.
- `y: number` — The y of the body's centre, in world units; a larger y is lower.
- `vx: number` — Horizontal speed, in units a second.
- `vy: number` — Vertical speed, in units a second; negative is rising.
- `frame: number` — Ticks played since the start.
- `grounded: boolean` — Whether the runner stands on a roof.
- `support: string | null` — The id of the roof it stands on, or null in the air.
- `held: boolean` — Whether jump was held on the last tick; a jump needs a fresh press.
- `coyote: number` — Ticks left (at most 4) in which a jump is still allowed after leaving a roof.
- `jumps: number` — Jumps made so far.
- `hits: string[]` — The ids of the crates already clipped.
- `won: boolean` — Whether the finish was reached.
- `lost: boolean` — Whether the run has ended in a loss.
- `reason: string` — A sentence on how the run stands, such as why it was lost.
- `distance: number` — The furthest the runner has got from the start along x, in world units.

### `RooftopStream`

```ts
type RooftopStream = ReturnType<typeof createRooftopStream>
```

An endless run made by `createRooftopStream`.

### `RooftopStyle`

```ts
type RooftopStyle = 'skyline' | 'girders' | 'obstacles' | 'mixed'
```

The look of a generated course: `'skyline'` buildings and towers, `'girders'` girder roofs between buildings, `'obstacles'` crates and hazards on the roofs, `'mixed'` a bit of each.

---

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