---
title: "Platform walker: API"
package: "@phaser-ae/platform-walker"
tier: Pro
version: 3.0.0-3
released: 2026-10-14
updated: 2026-10-19
description: "Arcade platform movement for players and enemies alike, with walking, fixed or variable jumps, falls, ladders, bars, screen wrap and riding moving platforms, all driven by simple intents."
url: https://phaser.io/packs/platform-walker/api
site: Phaser - https://phaser.io
---

# Platform walker: API

`@phaser-ae/platform-walker` — Kinematic arcade platform movement for players and enemies: walk, fixed or variable jumps, falls, ladders, bars, wrap and riding moving platforms.

## The pack

### `platformWalker`

```ts
function platformWalker(): Pack<{ platformWalker: typeof api }>
```

Install the renderer-independent platform walker API.

## Helpers

### `bubbleBobbleProfile`

```ts
function bubbleBobbleProfile(o: PresetOptions = {}): WalkerProfile
```

Bubble Bobble (1986): one-way platforms jumped through from below, variable jump height, air steering,
falling out of the bottom re-enters at the top (map `wrapY`). Speeds and heights are estimates from play.

### `createWalkerWorld`

```ts
function createWalkerWorld(o: WalkerWorldOptions): WalkerWorld
```

Create a walker world over a map.

### `jumpmanProfile`

```ts
function jumpmanProfile(o: PresetOptions = {}): WalkerProfile
```

Donkey Kong's Jumpman (1981). Walk 2 px in 3 frames (40 px/s), climb 2 px per 5 frames (24 px/s), the air
moves 1 px in 2 frames (30 px/s) (TASVideos frame analyses). The jump is a fixed arc chosen at take-off with
no steering and no jumping from ladders. The arc height (about 14 px, enough to clear a barrel) and the fall
limit (falls taller than Mario are fatal) are estimates from play; no disassembly figure is published.

### `labPlayerProfile`

```ts
function labPlayerProfile(o: PresetOptions = {}): WalkerProfile
```

A friendly modern-arcade player for custom levels: variable jump, air control, ladders and bars.

### `lodeRunnerProfile`

```ts
function lodeRunnerProfile(o: PresetOptions = {}): WalkerProfile
```

Lode Runner (1983): grid-aligned running and climbing at one speed, no jump, constant-speed falls, catching
ladders and bars while falling, stepping off ladders sideways at any row, dropping from bars. Speeds are
estimates (the runner crosses a 28-column screen in about five seconds).

### `marioBrosProfile`

```ts
function marioBrosProfile(o: PresetOptions = {}): WalkerProfile
```

Mario Bros (1983): momentum walking with a skid, a high fixed arc with slight steering, head bumps on the
solid floors above, the screen wrapping left and right, ice floors. Speeds and heights are estimates from play.

### `snowBrosProfile`

```ts
function snowBrosProfile(o: PresetOptions = {}): WalkerProfile
```

Snow Bros (1990): like Bubble Bobble with down plus jump dropping through floors. Estimates from play.

### `spacePanicProfile`

```ts
function spacePanicProfile(o: PresetOptions = {}): WalkerProfile
```

Space Panic (1980): walk floors and climb ladders, no jump; aliens fall into dug holes (a dig-trap rule). Estimates.

### `walkerProfile`

```ts
function walkerProfile(input: WalkerProfileInput = {}, base?: WalkerProfile): WalkerProfile
```

Build a complete profile: defaults (a 12 x 16 body for 8-unit tiles), then a base, then overrides.

## Types

### `AirHorizontal`

```ts
type AirHorizontal = "fixed" | "keep" | "control"
```

How horizontal speed behaves in the air during a jump.

### `ClimbProfile`

```ts
interface ClimbProfile
```

Ladders.

- `enabled: boolean` — May climb at all.
- `speed: number` — Climbing speed upward, units per second.
- `downSpeed: number` — Climbing speed downward, units per second.
- `snap: number` — How far from a ladder's centre a body may be and still grab it, world units.
- `glide: number` — Centring speed toward the ladder's centre while climbing, units/s. 0 snaps at once.
- `exit: "ends" | "anywhere"` — Leave ladders only at their ends ('ends', Donkey Kong) or sideways at any row onto floor or bar ('anywhere', Lode Runner).
- `broken: "block" | "pass" | "up"` — Broken ladder cells stop climbers ('block', Donkey Kong's Jumpman), are passed ('pass', barrels), or are passed going up only ('up': pull yourself up a broken ladder, but never climb down one).
- `grabInAir?: boolean` — Pressing up or down while airborne (jumping or falling) grabs a ladder within `snap` (a house rule for Donkey Kong; the arcade never does). Default false.
- `catchWhenFalling: boolean` — A falling body that drops into a ladder cell catches it (Lode Runner).
- `enterFromTop: boolean` — Pressing down on a ladder's top enters it.
- `sideTolerance: number` — How close to a row boundary feet must be to step off sideways ('anywhere'), world units.
- `exitToAir?: boolean` — With `exit: 'anywhere'`: a sideways step off a ladder is allowed even where nothing supports the body beside it, so it walks off into the air and falls (Lode Runner). Absent or false: only onto floor, bar or another ladder.
- `alignToRow?: boolean` — With `exit: 'anywhere'`: a sideways push while between rows first moves the climber to the nearest row line (within a tile, on the ladder) from which that sideways step is possible, so holding a direction ends in a step off (Lode Runner centres vertically; a floors-only exit such as Space Panic's reaches the floor). Absent or false: no effect.

### `FallProfile`

```ts
interface FallProfile
```

Falling.

- `gravity: number` — Gravity, units/s².
- `maxSpeed: number` — Terminal falling speed, units per second.
- `mode: "accelerate" | "constant"` — 'accelerate' under gravity, or 'constant' speed (`maxSpeed`) when falling without a jump (Lode Runner).
- `walkOffCarry: number` — Fraction of horizontal ground speed kept when walking off an edge (0: drop straight down).
- `airAccel: number` — Steering acceleration while falling (not jumping), units/s²; 0 for none.
- `death: number | null` — Longest safe fall from the highest point reached, world units; longer falls are reported fatal. `null`: never.
- `bounce: number` — On landing faster than `bounceMin`, bounce up with this fraction of the landing speed (barrels). 0: none.
- `bounceMin: number` — Minimum landing speed that bounces, units per second.
- `centre?: number` — Grid games: speed (units per second) at which a body falling without a jump glides to the centre of its column, so it drops cleanly into a one-cell hole (Lode Runner centres fallers). 0 or absent: off (the default).
- `from?: "apex" | "takeoff"` — Where fall heights are measured from: the highest point reached ('apex', default) or, during a jump, the height it started from ('takeoff', Donkey Kong: death 15 px below take-off).

### `FlightProfile`

```ts
interface FlightProfile
```

Free flight (no gravity): flying enemies, debug cameras.

- `enabled: boolean` — Fly instead of walking.
- `speed: number` — Speed on each axis, units per second.
- `platforms: boolean` — Collide with one-way platforms from above.

### `HangProfile`

```ts
interface HangProfile
```

Hand-over-hand bars.

- `enabled: boolean` — May hang at all.
- `speed: number` — Speed along a bar, units per second.
- `catchWhenFalling: boolean` — A falling body catches a bar it falls into (except the bar it dropped from).

### `JumpKind`

```ts
type JumpKind = "none" | "fixed" | "variable"
```

How a jump is shaped.

### `JumpProfile`

```ts
interface JumpProfile
```

Jumping.

- `kind: JumpKind` — 'none' (Lode Runner, Space Panic), 'fixed' (arc decided at take-off: Donkey Kong, Mario Bros), 'variable' (release cuts it).
- `speed: number` — Upward take-off speed, units per second.
- `gravity: number | null` — Gravity while the jump rises and falls, units/s². `null` uses `fall.gravity`.
- `horizontal: AirHorizontal` — 'fixed': horizontal speed set at take-off from the stick (`airSpeed`); 'keep': ground speed carries; 'control': steer with `airAccel`.
- `airSpeed: number` — Horizontal speed in the air for 'fixed' and the steering target for 'control', units per second.
- `airAccel: number` — Steering acceleration for 'control', units/s².
- `cut: number` — Variable jumps: upward speed is multiplied by this when jump is released while rising.
- `fromLadder: boolean` — May jump while climbing.
- `fromHang: boolean` — May jump while hanging from a bar.
- `coyote: number` — Seconds after walking off an edge during which a jump is still allowed.
- `buffer: number` — Seconds a jump press is remembered before landing.
- `wallBounce: boolean` — Bounce back off walls hit in the air (horizontal speed reverses) instead of stopping.
- `steer?: number` — For 'fixed' and 'keep' jumps: steering acceleration toward the stick's direction at `airSpeed`, units/s² (a little air control). Default 0 (none).

### `MaterialRule`

```ts
interface MaterialRule
```

Per-material ground behaviour.

- `traction: number` — Braking multiplier (ice ~0.08): how quickly speed bleeds away when the stick is released or reversed.
- `accel?: number` — Acceleration multiplier. Default: `traction`.
- `speed?: number` — Top speed multiplier. Default 1.

### `PresetOptions`

```ts
interface PresetOptions
```

Options shared by the presets: the tile size the level uses (presets are authored for 8-unit tiles at 60 Hz).

- `tile?: number` — Tile size of the level in world units; every distance and speed scales by tile / 8. Default 8.

### `WalkerBody`

```ts
interface WalkerBody
```

A body in the world. Read through `world.body(id)` or `world.bodies()`; change through world calls.

- `id: string` — Unique id.
- `tags: string[]` — Free tags for rules and controllers ('player', 'enemy', 'barrel').
- `x: number` — Centre x, world units.
- `y: number` — Centre y, world units.
- `feet: number` — Bottom edge (feet), world units.
- `vx: number` — Velocity x, units per second.
- `vy: number` — Velocity y, units per second.
- `facing: -1 | 1` — -1 left, 1 right.
- `mode: WalkerMode` — Movement mode.
- `support: WalkerSupport | null` — What it stands on (ground mode), else null.
- `ladderCol: number | null` — The ladder column being climbed, or null.
- `jumping: boolean` — Inside a jump (as opposed to falling after walking off).
- `apex: number` — Highest point (smallest feet y) since leaving the ground: fall heights are measured from it.
- `stun: number` — Seconds of stun left (0 when not stunned). While stunned, intents are ignored.
- `flipped: boolean` — Stunned upside-down (flipped) rather than dazed.
- `ghost: boolean` — Knocked: no intents, ballistic; `ghost` passes through everything.
- `speedScale: number` — Multiplier on walk, climb, hang and flight speeds (anger, hurry-up).
- `enabled: boolean` — Disabled bodies are not moved, sensed or carried.
- `outside: boolean` — Below an open map bottom (or beyond an open side).
- `embedded: boolean` — Overlapping a solid cell (after a map edit or a crush).
- `wrapped: boolean` — Wrapped across the map this step: renderers should snap instead of interpolating.
- `snapped: boolean` — Moved discontinuously this step (wrap, teleport): renderers should snap.
- `intent: WalkerIntent` — The current intent.
- `profile: WalkerProfile` — Movement rules.
- `sensors: WalkerSensors` — Sensor readings from the end of the last step.
- `modeTime: number` — Seconds in the current mode.

### `WalkerBodyDef`

```ts
interface WalkerBodyDef
```

How to add a body. Position by centre (`x`, `y`) or by feet (`x`, `feet`).

- `id?: string` — Unique id; defaults to `${name}-${n}`.
- `name?: string` — Id prefix when `id` is omitted. Default 'body'.
- `x: number` — Centre x.
- `y?: number` — Centre y (or give `feet`).
- `feet?: number` — Feet y (bottom edge).
- `profile?: WalkerProfile | WalkerProfileInput` — Movement profile, complete or partial (merged over defaults).
- `facing?: -1 | 1` — Initial facing. Default 1.
- `tags?: string[]` — Tags.
- `enabled?: boolean` — Start disabled.

### `WalkerController`

```ts
interface WalkerController
```

Something that drives or reacts to bodies every step (enemy AI, bots, rule packs).

- `readonly id: string` — Controller id.
- `think?(world: WalkerWorld, dt: number): void` — Before bodies move: set intents.
- `sense?(world: WalkerWorld, dt: number): void` — After bodies move and sensors refresh: react.

### `WalkerEvent`

```ts
type WalkerEvent = | { kind: "jumped"; id: string; x: number; y: number } | { kind: "dropped"; id: string; x: number; y: number } | { kind: "landed"; id: string; fall: number; fatal: boolean; on: "map" | "surface"; surface: string; col: number; row: number; x: number; y: number } | { kind: "support-lost"; id: string; cause: "edge" | "removed" | "teleported" | "inactive"; surface: string } | { kind: "bumped"; id: string; col: number; row: number; surface: string; x: number; y: number } | { kind: "ladder-enter"; id: string; col: number; at: "bottom" | "top" | "fall" | "side" } | { kind: "ladder-exit"; id: string; col: number; at: "top" | "bottom" | "side" | "jump" | "removed" } | { kind: "hang-start"; id: string; row: number } | { kind: "hang-end"; id: string; row: number; cause: "drop" | "end" | "removed" | "jump" | "climb" } | { kind: "wrapped"; id: string; axis: "x" | "y" } | { kind: "hazard"; id: string; col: number; row: number; surface: string } | { kind: "embedded"; id: string; col: number; row: number; crushedBy: string; cause: "surface" | "edit" | "overlap" } | { kind: "out-of-bounds"; id: string; side: "left" | "right" | "top" | "bottom" } | { kind: "bounced"; id: string; surface: string } | { kind: "stun-end"; id: string }
```

Events, in order, from `drain()`.

### `WalkerIntent`

```ts
interface WalkerIntent
```

What a body wants this step. Players map keys to it; controllers compute it.

- `x: number` — -1 left .. 1 right.
- `y: number` — -1 up .. 1 down (ladders, dropping, flight).
- `jump: boolean` — Jump held. A press is detected from the previous step.

### `WalkerMode`

```ts
type WalkerMode = "ground" | "air" | "climb" | "hang" | "fly" | "knocked"
```

Movement mode.

### `WalkerProfile`

```ts
interface WalkerProfile
```

Everything about how one body moves. Serialisable; change at runtime with `setProfile`.

- `width: number` — Body width, world units.
- `height: number` — Body height, world units.
- `foot: number` — Half-span sampled for support under the feet, world units (0: centre only; arcade bodies fall when the centre leaves).
- `stepUp: number` — Highest ledge stepped up onto while walking, world units (stepped girders).
- `stepDown: number` — Deepest drop followed while walking without falling, world units.
- `walk: WalkProfile` — Walking.
- `jump: JumpProfile` — Jumping.
- `fall: FallProfile` — Falling.
- `climb: ClimbProfile` — Ladders.
- `hang: HangProfile` — Bars.
- `flight: FlightProfile` — Flight.
- `edge: "walk-off" | "stop"` — At an edge: fall off ('walk-off') or refuse to step past it ('stop').
- `wrap: boolean` — Follow the map's wrap (Mario Bros sides, Bubble Bobble bottom-to-top).
- `oneWayDrop: boolean` — Down plus a jump press drops through a one-way floor.
- `passPlatforms: boolean` — Ignore one-way floors and ladder tops entirely (a barrel plunging down the screen).
- `platform: boolean` — Other bodies can stand on this one (trapped guards, frozen enemies).
- `materials: Record<string, MaterialRule>` — Ground rules per map material name.

### `WalkerProfileInput`

```ts
type WalkerProfileInput = Partial<Omit<WalkerProfile, "walk" | "jump" | "fall" | "climb" | "hang" | "flight" | "materials">> & { /** Walking overrides. */ walk?: Partial<WalkProfile>; /** Jump overrides. */ jump?: Partial<JumpProfile>; /** Fall overrides. */ fall?: Partial<FallProfile>; /** Ladder overrides. */ climb?: Partial<ClimbProfile>; /** Bar overrides. */ hang?: Partial<HangProfile>; /** Flight overrides. */ flight?: Partial<FlightProfile>; /** Material rules (merged by name). */ materials?: Record<string, MaterialRule>; }
```

Any subset of a profile; nested groups merge field by field.

### `WalkerSensors`

```ts
interface WalkerSensors
```

Sensor readings refreshed after every step; what AI needs to decide.

- `wallAhead: boolean` — A wall directly ahead in the facing direction.
- `edgeAhead: boolean` — Grounded and no support under the leading edge ahead.
- `ladderUp: boolean` — A ladder that can be climbed upward from here (within grab range).
- `ladderDown: boolean` — A ladder that can be climbed downward from here.
- `ladderX: number | null` — Centre x of the nearest grabbable ladder, or null.
- `barHere: boolean` — Inside a bar cell.
- `col: number` — The cell the body occupies (feet row).
- `row: number` — The cell the body occupies (feet row).
- `hitWall: boolean` — Hit a wall horizontally this step.
- `hitCeiling: boolean` — Hit a ceiling this step.
- `hitFloor: boolean` — Landed or touched a floor this step (flight included).

### `WalkerSupport`

```ts
interface WalkerSupport
```

What a body is standing on.

- `on: "map" | "surface"` — A map cell or a provider surface.
- `surface: string` — Surface id when `on` is 'surface'.
- `col: number` — Supporting cell column (map support).
- `row: number` — Supporting cell row (map support).
- `kind: string` — Support kind ('solid', 'platform', 'ladder-top', 'bound', or the surface kind).
- `material: string` — Material name ('' none).
- `oneWay: boolean` — One-way support (can be dropped through).

### `WalkerWorld`

```ts
interface WalkerWorld
```

The hub of the platform mechanic layer. Create with `createWalkerWorld`.

- `readonly map: PlatformMap` — The level.
- `readonly dt: number` — Fixed step, seconds.
- `readonly time: number` — Simulated seconds.
- `readonly steps: number` — Fixed steps run.
- `add(def: WalkerBodyDef): string` — Add a body; returns its id.
- `remove(id: string): void` — Remove a body.
- `has(id: string): boolean` — Whether a body exists.
- `body(id: string): WalkerBody` — A copy of a body's state. Throws for an unknown id.
- `peek(id: string): Readonly<WalkerBody>` — A body's live state, not a copy: cheap enough to read many times a step. Read it within the step; never keep it across steps or write to it (the world changes it as it steps). Throws for an unknown id.
- `bodies(tag?: string): WalkerBody[]` — Copies of every body, in insertion order, optionally filtered by tag.
- `setIntent(id: string, intent: Partial<WalkerIntent>): void` — Set a body's intent for the coming steps.
- `setProfile(id: string, profile: WalkerProfileInput): void` — Patch a body's profile.
- `setSpeedScale(id: string, k: number): void` — Speed multiplier (anger, hurry-up).
- `setFacing(id: string, facing: -1 | 1): void` — Face a direction.
- `setTags(id: string, tags: string[]): void` — Replace a body's tags.
- `enable(id: string, on: boolean): void` — Enable or disable a body (disabled bodies are frozen and invisible to sensors and riders).
- `stun(id: string, seconds: number, o?: { flip?: boolean }): void` — Stun: ignore intents for `seconds` (flipped or dazed); the body still falls and is carried. 0 clears.
- `knock(id: string, o: { vx: number; vy: number; ghost?: boolean; seconds?: number; gravity?: number }): void` — Knock: launch ballistically, ignoring intents until landing (or for `seconds`); `ghost` passes through everything; `gravity` defaults to the profile's (at least 300).
- `teleport(id: string, x: number, feet: number): void` — Move instantly (flagged `snapped`); the body settles onto support next step.
- `grabLadder(id: string, col: number): boolean` — Put a body onto a ladder column at its current height (scripted climbs, AI recovery).
- `addProvider(p: SurfaceProvider): void` — Add a surface provider.
- `removeProvider(id: string): void` — Remove a surface provider by id.
- `addController(c: WalkerController): void` — Add a controller.
- `removeController(id: string): void` — Remove a controller by id.
- `surface(id: string): Surface | null` — Surfaces seen in the current step (all providers plus platform bodies), by id.
- `surfaces(): Surface[]` — Surfaces seen in the current step.
- `riders(): RiderMap` — Surface id to rider body ids, from the end of the last step.
- `overlaps(a: string, b: string, inset?: number): boolean` — Two bodies' boxes overlap (wrap-aware), shrunk by `inset` on every side.
- `query(left: number, top: number, right: number, bottom: number, tag?: string): WalkerBody[]` — Bodies whose boxes overlap a rectangle (wrap-aware), optionally by tag.
- `step(): void` — One fixed step: providers, controllers think, bodies move, riders and sensors, controllers sense.
- `tick(seconds: number): number` — Run whole fixed steps for elapsed seconds; returns the number run.
- `drain(): WalkerEvent[]` — Events since the last drain.
- `snapshot(): WalkerWorldSnapshot` — Serialisable state.
- `restore(s: WalkerWorldSnapshot): void` — Restore a snapshot (providers and controllers restore their own).

### `WalkerWorldOptions`

```ts
interface WalkerWorldOptions
```

World options.

- `map: PlatformMap` — The level.
- `providers?: SurfaceProvider[]` — Surface providers, stepped in order before bodies move.
- `controllers?: WalkerController[]` — Controllers, run in order.
- `step?: number` — Fixed step, seconds. Default 1/60.
- `maxSteps?: number` — Most fixed steps `tick` runs per call (spiral-of-death guard). Default 8.

### `WalkerWorldSnapshot`

```ts
interface WalkerWorldSnapshot
```

Serialisable world state (providers and controllers snapshot themselves).

- `bodies: BodyState[]` — Bodies in insertion order (with private movement state).
- `seq: number` — Id counter.
- `time: number` — Simulated seconds.
- `steps: number` — Steps run.
- `acc: number` — Unconsumed tick time.
- `riders: [string, string[]][]` — Riders at the end of the last step.
- `events: WalkerEvent[]` — Undrained events.

### `WalkProfile`

```ts
interface WalkProfile
```

Walking on the ground.

- `speed: number` — Top walking speed, units per second.
- `accel: number` — Acceleration toward the target speed, units/s². 0 is arcade-instant (full speed at once).
- `decel: number` — Braking when the stick is released or reversed, units/s². 0 stops dead.
- `turn?: number` — Braking while the stick points against the motion (the skid when turning), units/s². Default `decel`.

---

## For AI agents: Phaser AE

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