---
title: "First-person bosses: API"
package: "@phaser-ae/fps-bosses"
tier: Pro
version: 3.0.0-0
released: 2026-10-24
updated: 2026-10-24
description: "Boss fights for first-person shooters: phases set by health, with volleys, rings of shots, charges, slams, summons and teleports, each with a warning."
url: https://phaser.io/packs/fps-bosses/api
site: Phaser - https://phaser.io
---

# First-person bosses: API

`@phaser-ae/fps-bosses` — Boss fights for first-person shooters: phases by health, volleys, rings, bursts, charges, slams, summons, teleports, armour and invulnerability.

## The pack

### `fpsBosses`

```ts
function fpsBosses(): Pack<{ fpsBosses: typeof kit; }>
```

Compose boss fights under `game.fpsBosses`.

## Helpers

### `createBosses`

```ts
function createBosses(defs: BossDef[], horde: Horde, world: EnemyWorld, seed = 1): Bosses
```

Boss fights for the bosses of `defs` among `horde`'s enemies, on `world` (the map's `enemyWorld()`). Throws on a def it cannot fight.

## Classes

### `Bosses`

```ts
class Bosses
```

Boss fights for first-person shooters, on top of `fps-enemies`: an enemy of a boss kind is taken over (the horde
keeps its health, pain, death and sounds) and fought in phases set by its health. Each phase has a way of moving
(holding, chasing, strafing, keeping away) and a pattern of attacks with warning wind-ups: fanned volleys, rings of
shots, aimed bursts, charges, ground slams, summons and teleports. A new phase can bring invulnerability, healing and
reinforcements; phases can carry armour. Projectiles, summons and damage come back as events for the game to apply,
as the horde's do, so it works on any map an `EnemyWorld` describes. Get one from `createBosses`.

- `constructor(defs: BossDef[], horde: Horde, world: EnemyWorld, seed = 1)`
- `adopt(id: string): boolean` — Take over an enemy if its kind is a boss: returns true when it now fights as one. Call it for every enemy placed.
- `list(): BossState[]` — The bosses, for a health bar.
- `has(id: string): boolean` — Whether an enemy is a boss.
- `scale(id: string, damage: number): number` — The damage a boss actually takes from `damage`: none while invulnerable, less with its phase's armour. Other enemies take it all.
- `tick(dt: number, player: BossTarget): BossEvent[]` — Run the bosses on by `dt` seconds (0 to 1) against the player.
- `summoned(boss: string, enemy: string): void` — Tell the bosses an enemy they summoned now stands (the game spawned it), so `max` counts it.
- `get state(): BossesState` — A copy of the state.
- `restore(state: BossesState): void` — Put back a saved state.

## Types

### `BossAttack`

```ts
type BossAttack = | { kind: 'volley'; count: number; spread: number; projectile: BossProjectile; damage: [number, number]; repeat?: number; interval?: number; windup?: number; sound?: string } | { kind: 'ring'; count: number; projectile: BossProjectile; damage: [number, number]; repeat?: number; interval?: number; windup?: number; sound?: string } | { kind: 'burst'; shots: number; interval: number; projectile: BossProjectile; damage: [number, number]; spread?: number; windup?: number; sound?: string } | { kind: 'charge'; speed: number; time: number; damage: [number, number]; windup?: number; sound?: string } | { kind: 'slam'; radius: number; damage: [number, number]; knock?: number; windup?: number; sound?: string } | { kind: 'summon'; enemy: string; count: number; radius?: number; max?: number; windup?: number; sound?: string } | { kind: 'teleport'; to?: 'near' | 'behind' | [number, number][]; windup?: number; sound?: string }
```

One attack in a boss's pattern. Every attack has a `windup` (seconds of warning, default 0.6) and may name a `sound`.
- `volley`: `count` shots fanned across `spread` radians at the player, `repeat` times `interval` apart.
- `ring`: `count` shots all round, `repeat` times `interval` apart (each ring turned half a gap).
- `burst`: `shots` aimed shots `interval` apart, scattered by `spread`.
- `charge`: a rush at the player at `speed` for up to `time` seconds, hurting on contact.
- `slam`: a blow to the ground hurting a player within `radius` who is on the ground, and knocking them back.
- `summon`: `count` enemies of kind `enemy` around it within `radius`, while fewer than `max` it summoned stand.
- `teleport`: to a random point near the player, behind the player, or one of `to`'s points.

### `BossDef`

```ts
interface BossDef
```

A boss: an enemy kind that a horde already knows (its hit points, size and sprite), and how it fights.

- `id: string` — The enemy kind it drives. Every enemy of this kind on the map becomes this boss.
- `name?: string` — Its name, for the health bar; default the id.
- `phases: BossPhase[]` — Its phases, first to last.
- `wake?: number` — How near the player must come, in sight, to wake it; default 30. It wakes when hurt too.
- `sounds?: { wake?: string }` — Sounds: as it wakes.

### `BossesState`

```ts
interface BossesState
```

Everything that changes; a save holds exactly this.

- `bosses: Fight[]` — Each boss's fight.
- `rng: number[]` — The random stream.

### `BossEvent`

```ts
type BossEvent = | { type: 'boss-wake'; id: string; name: string } | { type: 'boss-phase'; id: string; phase: number } | { type: 'boss-windup'; id: string; attack: string; time: number } | { type: 'projectile'; id: string; x: number; y: number; z: number; yaw: number; pitch: number; speed: number; radius: number; damage: number; splash?: { radius: number; damage: [number, number]; knock?: number } } | { type: 'slam'; id: string; x: number; z: number; radius: number; damage: number; knock: number } | { type: 'charge-hit'; id: string; damage: number } | { type: 'summon'; id: string; enemy: string; x: number; z: number; yaw: number } | { type: 'teleport'; id: string; x: number; z: number } | { type: 'boss-died'; id: string } | { type: 'sound'; id: string; sound: string; x: number; y: number; z: number }
```

What the bosses did. Projectiles, summons and damage are the game's to apply.

### `BossPhase`

```ts
interface BossPhase
```

A stretch of a fight: how the boss moves and what it does until its health falls to `until`.

- `until?: number` — The share of its health (0 to 1) at which the next phase begins; the last phase has none.
- `move?: 'hold' | 'chase' | 'strafe' | 'keep-away'` — How it moves between attacks: `'hold'` its ground, `'chase'` the player, `'strafe'` round them, or `'keep-away'` at `range`. Default `'chase'`.
- `speed?: number` — Movement speed, units per second; default 2.5.
- `range?: number` — Distance it keeps when strafing or keeping away; default 8.
- `attacks: BossAttack[]` — Its attacks.
- `order?: 'cycle' | 'random'` — `'cycle'` through the attacks in order (default) or pick at `'random'`.
- `pause?: [number, number]` — Seconds between attacks, `[min, max]`; default [1, 2].
- `armor?: number` — Damage it takes is multiplied by this, 0 (none) to 1 (all); default 1.
- `enter?: { sound?: string; invulnerable?: number; summon?: { enemy: string; count: number; radius?: number }; heal?: number }` — What happens as the phase begins: a `sound`, seconds `invulnerable`, a `summon`, a share of health healed.

### `BossProjectile`

```ts
interface BossProjectile
```

A boss's shot: speed and radius in world units, and an optional blast.

- `speed: number` — Units per second.
- `radius: number` — Radius.
- `splash?: { radius: number; damage: [number, number]; knock?: number }` — A blast where it lands.

### `BossState`

```ts
interface BossState
```

A boss now.

- `id: string` — The enemy's id.
- `def: string` — Its kind.
- `name: string` — Its name.
- `hp: number` — Hit points left.
- `max: number` — Hit points at full health.
- `phase: number` — Phase index.
- `awake: boolean` — Awake and fighting.
- `dead: boolean` — Dead.
- `stage: 'idle' | 'windup' | 'attack'` — `'idle'`, `'windup'` or `'attack'`.
- `attack: string` — The attack under way, by kind, or ''.
- `invulnerable: number` — Seconds of invulnerability left.

### `BossTarget`

```ts
interface BossTarget
```

The player as a boss sees them.

- `x: number` — Position.
- `z: number` — Position.
- `y?: number` — Feet height; default 0.
- `height?: number` — Height; default 1.6.
- `yaw?: number` — Facing (for teleporting behind them); default 0.
- `grounded?: boolean` — Standing on the ground (a slam only hurts the grounded); default true.
- `alive: boolean` — Alive.

---

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