---
title: "Encounter director: API"
package: "@phaser-ae/encounter-director"
tier: Pro
version: 3.0.0-3
released: 2026-10-14
updated: 2026-10-19
description: "Plans timed, warned hazards across lanes, by seed or by hand, and plays them back, always leaving a safe lane and always time to reach it."
url: https://phaser.io/packs/encounter-director/api
site: Phaser - https://phaser.io
---

# Encounter director: API

`@phaser-ae/encounter-director` — Fair, timed plans of warned hazards across lanes, by seed or by hand, and a director that plays them: always a safe lane, always time to reach it.

## The pack

### `encounterDirector`

```ts
function encounterDirector(): Pack<{ encounterDirector: EncounterDirectorApi }>
```

The `encounter-director` pack: `game.encounterDirector`. No options.

## Helpers

### `createEncounter`

```ts
function createEncounter(plan: EncounterPlan): EncounterDirector
```

Play a plan. Throws, with every fault, on a plan `validateEncounter` refuses.

### `encounterKinds`

```ts
const encounterKinds: HazardKind[]
```

The built-in hazard kinds.

### `encounterPhases`

```ts
const encounterPhases: EncounterPhase[]
```

The built-in phases.

### `generateEncounter`

```ts
function generateEncounter(options: EncounterOptions = {}): EncounterPlan
```

Generate a plan. Throws, with every fault, when the options cannot make a fair one.

### `validateEncounter`

```ts
function validateEncounter(plan: EncounterPlan): string[]
```

Check a plan: timing, lanes, a safe lane at every moment, the budget, and time to reach safety. Empty when fair.

## Types

### `EncounterDirector`

```ts
interface EncounterDirector
```

A plan being played.

- `readonly plan: EncounterPlan` — The plan.
- `readonly time: number` — Seconds played.
- `readonly done: boolean` — True once the plan has run out.
- `readonly phase: string` — The phase now.
- `tick(dt: number): void` — Advance `dt` seconds.
- `hazards(): (HazardCue & { active: boolean; left: number })[]` — The hazards warning or live now, with `active` true for the live ones and `left` the seconds to the next change.
- `safeLanes(): number[]` — The lanes no live hazard covers.
- `live(lane: number): boolean` — True when a lane is covered by a live hazard.
- `drain(): EncounterEvent[]` — Events since the last call.
- `snapshot(): { time: number }` — The time, as plain JSON, to restore.
- `restore(save: { time: number }): void` — Go back (or on) to a saved time.

### `EncounterDirectorApi`

```ts
interface EncounterDirectorApi
```

What the `encounter-director` pack adds to a game: `game.encounterDirector`.

- `create: typeof createEncounter` — Play a plan.
- `generate: typeof generateEncounter` — Generate a fair plan by seed.
- `validate: typeof validateEncounter` — Check a plan.
- `kinds: typeof encounterKinds` — The built-in hazard kinds.
- `phases: typeof encounterPhases` — The built-in phases.

### `EncounterEvent`

```ts
type EncounterEvent = | { kind: 'warning' | 'active' | 'ended'; id: string; time: number } | { kind: 'phase'; name: string; time: number } | { kind: 'complete'; time: number }
```

Something the director says.

### `EncounterOptions`

```ts
interface EncounterOptions
```

What an encounter is generated from.

- `seed?: number` — The seed. Default 1.
- `lanes?: EncounterRange` — How many lanes. Default `[5, 7]`.
- `duration?: number` — Its length in seconds. Default 40.
- `budget?: number` — The most cost live at once. Default 3.
- `warning?: number` — The least warning, in seconds. Default 1.6.
- `laneTime?: number` — Seconds to cross one lane: warnings stretch so the furthest lane can reach a safe one. Default 0.7.
- `gap?: number` — Seconds of calm after a hazard before the next, at no pressure. Default 1.6.
- `kinds?: HazardKind[]` — The hazard kinds. Default `encounterKinds`.
- `phases?: EncounterPhase[]` — The phases. Default probe, pressure and finale.
- `intensity?: number` — Raises every phase's pressure: 0 as written, 1 as hard as it goes. Default 0.

### `EncounterPhase`

```ts
interface EncounterPhase
```

A stretch of the encounter.

- `name: string` — Its name.
- `at: number` — Where it starts, as a fraction of the encounter.
- `pressure: number` — How hard it presses, 0 to 1: how many lanes a hazard takes, how close hazards follow, whether they overlap.

### `EncounterPlan`

```ts
interface EncounterPlan
```

A plan: what the director plays.

- `seed: number` — The seed the plan was generated from; 1 for the default.
- `lanes: number` — How many lanes the encounter has, a whole number from 2 to 100; cues name lanes 0 to `lanes - 1`.
- `budget: number` — The most cost that may be live at once.
- `minWarning: number` — The least warning a cue may have.
- `secondsPerLane: number` — Seconds to cross a lane.
- `duration: number` — Seconds.
- `phases: { at: number; name: string }[]` — Phases by start time in seconds.
- `cues: HazardCue[]` — Every hazard in the encounter.

### `EncounterRange`

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

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

### `HazardCue`

```ts
interface HazardCue
```

One hazard in a plan.

- `id: string` — Its unique name within the plan, such as `'cue-0'`; events refer to the cue by it.
- `kind: string` — Its kind's name.
- `at: number` — When its warning starts, seconds into the encounter.
- `warning: number` — Seconds of warning.
- `duration: number` — Seconds live after it.
- `lanes: number[]` — The lanes it hits.
- `cost: number` — Its cost against the budget.

### `HazardKind`

```ts
interface HazardKind
```

A kind of hazard.

- `id: string` — Its name: `'beam'`, `'pulse'`, a game's own.
- `cost?: number` — What it costs against the budget while it is live. Default 1.
- `duration?: EncounterRange` — Seconds it is live. Default `[0.65, 1.3]`.
- `shape?: 'block' | 'scatter' | 'alternate'` — How the lanes it hits lie: side by side (`'block'`), anywhere (`'scatter'`), or every other (`'alternate'`). Default `'scatter'`.
- `weight?: number` — How common against the other kinds. Default 1.

---

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