---
title: "First-person weapons: API"
package: "@phaser-ae/fps-weapons"
tier: Pro
version: 3.0.0-0
released: 2026-10-24
updated: 2026-10-24
description: "The weapons of a first-person shooter as rules: melee, hitscan and projectile guns with rates, ammunition, pellets, spread, falloff and switching."
url: https://phaser.io/packs/fps-weapons/api
site: Phaser - https://phaser.io
---

# First-person weapons: API

`@phaser-ae/fps-weapons` — A first-person arsenal: hitscan, projectile and melee weapons with rates, auto fire, ammunition types, pellets, spread, falloff and switching.

## The pack

### `fpsWeapons`

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

Compose the weapons and ammunition rules under `game.fpsWeapons`.

## Helpers

### `createArsenal`

```ts
function createArsenal(config: ArsenalConfig): Arsenal
```

Make an arsenal. Throws, naming the field, on a config it cannot use.

### `scaleDamage`

```ts
function scaleDamage(damage: number, dist: number, falloff?: { from: number; to: number; min: number }): number
```

Damage after falloff: full up to `falloff.from` cells, falling linearly to `falloff.min` of it at `falloff.to`
cells and beyond. Without a falloff, the damage unchanged. Rounded to a whole number.

## Classes

### `Arsenal`

```ts
class Arsenal
```

A player's weapons and ammunition: which are carried, which is in hand, the trigger, rates of fire, raising and
lowering, automatic switching when a weapon runs dry, and pickups. It decides when a shot goes off and with what
pellets and damage; the game resolves each pellet against its world (`cell-dungeon`'s ray, its enemies). Time moves
only through `tick`. Get one from `createArsenal`.

- `constructor(config: ArsenalConfig)`
- `get state(): ArsenalState` — A copy of the state.
- `get current(): WeaponDef` — The weapon in hand.
- `get owned(): string[]` — The weapons carried, best last.
- `ammo(type: string): number` — Ammunition carried of a type (0 for an unknown type).
- `get rounds(): number | null` — Ammunition for the weapon in hand, or null when it needs none.
- `weapon(id: string): WeaponDef | undefined` — A weapon's definition, or undefined.
- `get view(): { phase: ArsenalState['phase']; raised: number; recoil: number }` — How far the weapon in hand is through raising (0 to 1, 1 when ready), for drawing it coming up or going down.
- `trigger(held: boolean): void` — Hold or release the trigger.
- `select(id: string): boolean` — Switch to a carried weapon: the one in hand lowers, then this one rises. False when it is not carried or already in hand.
- `cycle(direction: 1 | -1): boolean` — Switch to the next (1) or previous (−1) carried weapon that can fire.
- `give(id: string, ammo = 0): ArsenalEvent[]` — Pick up a weapon (with `ammo` rounds of its type, default 0): it is carried from now on. Switches to it when it is better than the one in hand.
- `addAmmo(type: string, amount: number): number` — Add ammunition, up to the type's maximum. Returns how much was taken (0 when full or unknown).
- `max(type: string): number` — The most of an ammunition type that can be carried now; 0 for an unknown type.
- `setMax(type: string, max: number): void` — Carry more of an ammunition type (a backpack): the maximum becomes `max`, 1 to 100000. Unknown types are ignored.
- `tick(dt: number): { shots: WeaponShot[]; events: ArsenalEvent[] }` — Run the arsenal on by `dt` seconds (0 to 10): raising and lowering, cooldowns, and shots while the trigger allows.
- `restore(state: ArsenalState): void` — Put back a saved state. Throws on one that names weapons this arsenal lacks.

## Types

### `AmmoDef`

```ts
interface AmmoDef
```

An ammunition type.

- `id: string` — Unique id.
- `max: number` — Most that can be carried, 1 to 100000.
- `start?: number` — How much a new arsenal has; default 0.

### `ArsenalConfig`

```ts
interface ArsenalConfig
```

A player's arsenal.

- `weapons: WeaponDef[]` — Every weapon there is, in order of preference (later is better when switching automatically). 1 to 32.
- `ammo: AmmoDef[]` — Every ammunition type.
- `owned?: string[]` — Weapons carried at the start; default the first.
- `current?: string` — The weapon in hand at the start; default the best owned one with ammunition.
- `autoSwitch?: boolean` — Switch to the best owned weapon with ammunition when the one in hand runs dry; default true.
- `seed?: number` — Seed for damage and spread, 0 to 4294967295; default 1.

### `ArsenalEvent`

```ts
type ArsenalEvent = | { type: 'switched'; weapon: string } | { type: 'empty'; weapon: string } | { type: 'picked-up'; weapon: string }
```

What a step did besides firing.

### `ArsenalState`

```ts
interface ArsenalState
```

Everything that changes; a save holds exactly this.

- `owned: string[]` — Weapons carried, by id, in the config's order.
- `ammo: Record<string, number>` — Ammunition by type.
- `current: string` — The weapon in hand (or being raised).
- `phase: 'ready' | 'cooldown' | 'lowering' | 'raising'` — `'ready'`, `'cooldown'` (between shots), `'lowering'` or `'raising'`.
- `timer: number` — Seconds left in the phase.
- `next: string | null` — The weapon to raise once this one is lowered, or null.
- `held: boolean` — Whether the trigger is held.
- `spent: boolean` — Whether this press has already fired (one-shot weapons).
- `shots: number` — Shots fired.
- `rng: number[]` — The random stream.
- `maxes?: Record<string, number>` — Ammunition maximums raised above the config's (a backpack), by type.

### `WeaponDef`

```ts
interface WeaponDef
```

A weapon.

- `id: string` — Unique id, 1 to 100 characters.
- `kind: WeaponKind` — `'hitscan'` (an instant ray per pellet), `'projectile'` (something that flies) or `'melee'` (a short reach).
- `damage: [number, number]` — Damage per pellet, `[min, max]` whole numbers from 0 to 10000, drawn evenly.
- `rate: number` — Seconds between shots, 0.03 to 10.
- `auto?: boolean` — True: fires again while the trigger is held. False (default): one shot per press.
- `ammo?: string` — The ammunition type it uses; none (the default) for a weapon that needs none.
- `cost?: number` — Ammunition per shot, 1 to 100; default 1.
- `pellets?: number` — Pellets (rays or projectiles) per shot, 1 to 64; default 1.
- `spread?: number` — Half-angle of the cone pellets scatter in, radians, 0 to 1; default 0.
- `range?: number` — Reach in cells, 0.5 to 512; default 64, or 1.5 for melee.
- `falloff?: { from: number; to: number; min: number }` — Damage falls from full at `from` cells to `min` (0 to 1) at `to` cells; default none.
- `projectile?: { speed: number; radius: number; splash?: { radius: number; damage: [number, number]; knock?: number } }` — Projectile weapons: speed in units per second, radius in units, and splash damage around where it lands, with `knock`, how hard the blast pushes bodies away (units per second at its centre; default 0).
- `raise?: number` — Seconds to raise it when switched to, 0 to 5; default 0.2.
- `lower?: number` — Seconds to lower it when switching away, 0 to 5; default 0.2.
- `noise?: number` — How many units away a shot is heard, 0 to 256; default 16, or 0 for melee.
- `sound?: string` — The sound of a shot, by name, for the game to play; default none.

### `WeaponKind`

```ts
type WeaponKind = 'hitscan' | 'projectile' | 'melee'
```

How a weapon delivers its damage.

### `WeaponShot`

```ts
interface WeaponShot
```

One shot: what the game resolves against the world.

- `weapon: string` — The weapon's id.
- `kind: WeaponKind` — How it delivers damage.
- `pellets: { yaw: number; damage: number }[]` — Each pellet: its angle off the aim (radians, positive turns right like the engine's yaw) and its damage before falloff.
- `range: number` — Reach in cells.
- `noise: number` — Units away it is heard.
- `sound?: string` — The weapon's `sound`, if it has one.
- `falloff?: { from: number; to: number; min: number }` — The falloff to apply by distance with `scaleDamage`, if any.
- `projectile?: { speed: number; radius: number; splash?: { radius: number; damage: [number, number]; knock?: number } }` — Projectile settings, for projectile weapons.

---

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