--- title: "Flight formation shooter: API" package: "@phaser-ae/flight-formation" tier: Pro version: 3.0.0-1 released: 2026-10-19 updated: 2026-10-20 description: "A fixed shooter whose enemies fly in along flight paths, sway in formation and peel off to dive with escorts, with tractor-beam captures, rescues and challenging stages." url: https://phaser.io/packs/flight-formation/api site: Phaser - https://phaser.io --- # Flight formation shooter: API `@phaser-ae/flight-formation` — Formation-shooter rules: fly-in flight programs, a swaying formation, dives with escorts, tractor-beam capture and rescue, challenging stages, as in Galaga. ## The pack ### `flightFormation` ```ts function flightFormation(): Pack<{ flightFormation: FlightFormationApi }> ``` Install the renderer-independent flight-formation rules (Galaga). ## Helpers ### `createGalaga` ```ts function createGalaga(config: GalagaConfig) ``` Create an independent flight-formation game. No renderer or kernel clock is required. ### `galagaEntry` ```ts function galagaEntry(slots: GalagaSlot[], size = 8, waveGap = 3): EntryWave[] ``` Entry groups for any slot list: groups of `size` in slot order, cycling the five arcade approaches. ### `galagaPreset` ```ts function galagaPreset(o: GalagaPresetOptions = {}): GalagaConfig ``` Galaga (Namco, 1981) as data. Classic values: 224x288 screen; 4 Boss Galaga, 16 butterflies (Goei) and 20 bees (Zako) entering in five groups of eight; sway while arriving, then breathing; bees 50/100, butterflies 80/160, bosses 150 in formation and 400/800/1600 diving with 0/1/2 escorts already shot, a captured fighter 500/1000; bosses take two hits; tractor-beam capture and rescue into a dual fighter; challenging stages 3, 7, 11... with 40 one-hit flyers, 100 per hit, 10,000 for all 40 and group bonuses of 1,000-3,000; two missiles in flight; extra fighters at 20,000, 70,000 and every 70,000. Flight programs are reference-style approximations, not ROM tables. ### `galagaPrograms` ```ts function galagaPrograms(): Record ``` Flight programs of the classic preset. Dives are authored for the RIGHT half; the left half mirrors them. ### `galagaSlots` ```ts function galagaSlots(rows: GalagaRow[]) ``` Slots for centred rows on a grid as wide as the widest row. ### `ramp` ```ts function ramp(r: Ramp, stage: number) ``` Evaluate a ramp at a 1-based stage. ## Classes ### `Galaga` ```ts class Galaga ``` Owns a flight-formation game: entries, formation sway/breathing, dives, escorts, capture, rescue, challenging stages. - `readonly config: GalagaConfig` — The validated definition (a private copy). - `constructor(config: GalagaConfig)` - `isChallenging(stage: number)` — Is this 1-based stage a challenging stage? - `get state(): GalagaState` — A copy of the whole state. - `slotPosition(slotId: string, offsetY = 0)` — Where a slot sits right now, including sway and breathing. - `get beams()` — Active beams for drawing. - `tick(seconds: number, input: GalagaInput = {})` — Advance by real seconds in fixed steps. - `step(input: GalagaInput = {})` — Advance exactly one fixed step. - `launchDive(id?: string): string | null` — Launch a dive now by the configured selection rules; returns the leader id or null. - `drain()` — Take the events since the last drain. - `snapshot()` — Serializable snapshot of the whole game. - `restore(snap: ReturnType)` — Restore a snapshot taken from the same configuration. - `reset(stage = 1)` — New game from `stage` (default 1). ## Types ### `EntryWave` ```ts interface EntryWave ``` One entry group: members leave from `start` along `program`, `gap` seconds apart (or in pairs). - `members: string[]` — Slot ids (normal stages) or kind ids (challenging stages). - `program: string` — Flight program the members fly. - `start: { x: number; y: number }` — Where the first member appears. - `heading: number` — Initial heading in degrees (0 right, 90 down). - `mirror?: boolean` — Mirror the program (negated turns, heading reflected). - `pairs?: "mirror" | "abreast"` — Members fly two abreast, the second mirrored about the screen centre (top entries) or offset. - `gap: number` — Seconds between members (or pairs). - `at: number` — Seconds after the stage's entry starts. ### `FlightEnd` ```ts type FlightEnd = "formation" | "wrap" | "exit" | "beam" ``` How a program ends. ### `FlightFormationApi` ```ts type FlightFormationApi = typeof galaga & typeof presets ``` `game.flightFormation`: the flight-formation rules owner, its preset and its builders. ### `FlightProgram` ```ts interface FlightProgram ``` A named program and its ending. - `steps: FlightStep[]` — Steps flown in order. - `then: FlightEnd` — What the flyer does when the steps run out. ### `FlightStep` ```ts interface FlightStep ``` One step of a flight program. - `seconds: number` — Duration of the step. - `turn?: number` — Degrees per second, positive = clockwise on screen. Negated when the program is mirrored. - `speed?: number` — Multiplies the flight's base speed. Default 1. - `aim?: number` — Steer toward the player at up to this many degrees per second. - `untilY?: number` — End the step early once the flyer is at or below this y. - `fire?: boolean` — Shots may be fired during this step (up to the dive's `perDive` budget, `gap` apart, within the fire band). ### `GalagaConfig` ```ts interface GalagaConfig ``` Complete flight-formation definition; {@link galagaPreset } builds the arcade one. - `width: number` — Playfield width in model pixels. - `height: number` — Playfield height in model pixels. - `hz: number` — Fixed simulation steps per second. - `seed?: number` — Seed for selection, capture and entry-fire chances. - `kinds: GalagaKind[]` — Enemy kinds. - `formation: { slots: GalagaSlot[]; /** Grid width in columns (slot cols index into it). */ columns: number; centerX: number; /** Centre y of row 0. */ top: number; spacingX: number; spacingY: number; /** Side-to-side drift while the fleet is still arriving. */ sway: { amplitude: number; period: number }; /** Expansion and contraction once every enemy has arrived (fraction of spacing). */ breathe: { amount: number; period: number }; }` — Formation grid, slots and motion. - `programs: Record` — Named flight programs for entries, dives, captures and challenging stages. - `stages: { /** First challenging stage (null = none) and the interval after it. Original: 3 and 4. */ challengingFirst: number | null; challengingEvery: number; /** Entry waves for normal stages. */ entry: EntryWave[]; /** Challenging stage wave sets, cycled by challenging-stage index. */ challenging: EntryWave[][]; introSeconds: number; clearSeconds: number; resultSeconds: number; }` — Stage sequence: entries, challenging stages and their timings. - `entrySpeed: Ramp` — Entry flight speed by stage (px/s). - `attack: { speed: Ramp; /** Seconds between dive launches. */ interval: Ramp; /** Simultaneous dive groups. */ maxDivers: Ramp; /** Relative chance a dive picks each kind. */ weights: Record; /** Once this few remain the attack quickens: half the interval and one more simultaneous dive. */ frenzyAtOrBelow: number; /** Dives start only after the whole fleet has arrived. */ afterEntry: boolean; /** Speed while flying home to a slot. */ homeSpeed: number; }` — Dive selection, timing and speed rules. - `capture: { program: string; /** Chance a capture-capable kind's dive is a capture dive when a capture is allowed. */ chance: Ramp; beamWidth: number; /** Beam reach below the boss. */ beamLength: number; /** Opening, holding and closing seconds. */ beamOpen: number; beamHold: number; beamClose: number; pullSeconds: number; /** The captured ship's enemy kind (scored when shot). */ fighterKind: string; /** Program the hostile fighter dives with after its boss died in formation. */ hostileDive: string; } | null` — Tractor-beam capture rules, or null for none. - `fire: { speed: Ramp; maxActive: number; /** Shots per dive. */ perDive: Ramp; /** Seconds between a diver's shots. */ gap: number; /** Only fire between these heights. */ minY: number; maxY: number; /** Largest angle from straight down. */ maxAngle: number; /** Chance an entering enemy fires once. */ entryChance: Ramp; width: number; height: number; }` — Enemy fire rules. - `player: { y: number; width: number; height: number; speed: number; minX: number; maxX: number; lives: number; extraLives: number[]; /** After the last listed threshold, another every this many points (0 = none). */ extraEvery: number; /** Missiles in flight for a single fighter; a dual fighter fires pairs up to twice this. Original: 2. */ maxShots: number; shotSpeed: number; shotWidth: number; shotHeight: number; dualSpacing: number; requireRelease: boolean; deathSeconds: number; }` — Fighter movement, missiles, lives and extra lives. - `challengeScoring: { perHit: number; perfect: number; /** Bonus for destroying a whole group, by challenging-stage index (last repeats). */ groupBonus: number[]; }` — Challenging-stage bonuses. ### `GalagaEnemy` ```ts interface GalagaEnemy ``` One enemy (or captured fighter) with its flight state. - `id: string` — Stable id (slot id in normal stages). - `kind: string` — Kind id. - `slot: string | null` — Formation slot, or null for challenging flyers. - `slotOffsetY: number` — Extra formation offset (a hostile fighter sits above its old boss). - `hp: number` — Remaining hits. - `phase: GalagaPhase` — Current phase. - `x: number` — Centre x. - `y: number` — Centre y. - `heading: number` — Heading in degrees (0 right, 90 down). - `program: string` — Flight program being flown. - `step: number` — Index of the current program step. - `stepTime: number` — Seconds into the current step. - `mirror: boolean` — Flying the mirrored program. - `entering: boolean` — Flying an entry route (scores diving points, cannot be selected to attack). - `diving: boolean` — Part of a dive: scores its diving value. - `spawnAt: number` — Stage time at which it enters. - `wave: number` — Entry group index (-1 for a captured fighter). - `leader: string | null` — Boss this escort follows, if any. - `offsetX: number` — Escort offset from its leader. - `offsetY: number` — Escort offset from its leader. - `escortsLaunched: number` — Escorts that left with this boss. - `escortsKilled: number` — Of those, destroyed before this boss. - `captive: string | null` — Id of a captured fighter riding with this enemy. - `rider: string | null` — Rider/puller: the boss this fighter belongs to. - `beamTime: number` — Seconds into the tractor beam. - `fireLeft: number` — Shots still to fire on this flight. - `fireClock: number` — Seconds until the next shot may fire. - `animTime: number` — Seconds of the current pull/rescue animation. - `exit: boolean` — While leaving: true = gone for good off screen, false = wrap back in from the top. - `speed: number` — Base flight speed for this flight (px/s). ### `GalagaEvent` ```ts type GalagaEvent = | { kind: "stage-start"; stage: number; challenging: boolean } | { kind: "player-fire"; x: number; y: number } | { kind: "enemy-hit"; id: string; enemy: string; x: number; y: number } | { kind: "enemy-killed"; id: string; enemy: string; score: number; x: number; y: number; diving: boolean } | { kind: "dive"; id: string; enemy: string; escorts: string[]; capture: boolean } | { kind: "beam"; id: string } | { kind: "captured"; boss: string; fighter: string } | { kind: "captive-hostile"; fighter: string } | { kind: "rescued"; fighter: string } | { kind: "player-hit"; x: number; y: number; dual: boolean } | { kind: "player-ready" } | { kind: "extra-life"; lives: number } | { kind: "group-bonus"; score: number; x: number; y: number } | { kind: "stage-clear"; stage: number } | { kind: "challenge-result"; hits: number; total: number; bonus: number; perfect: boolean } | { kind: "game-over" } ``` Ordered notifications for presentation: drain() them each frame. ### `GalagaInput` ```ts interface GalagaInput ``` One step of player input. - `move?: number` — -1 left, 0 still, +1 right. - `fire?: boolean` — Fire held. ### `GalagaKind` ```ts interface GalagaKind ``` An enemy type. - `id: string` — Kind id referenced by slots, waves and weights. - `formationScore: number` — Score when destroyed in formation, and while flying (entering, diving or returning). - `divingScore: number` — Score when destroyed while flying. - `escortScores?: number[]` — Diving score by number of its escorts destroyed earlier in the same dive (boss: 400/800/1600). - `hp: number` — Hits to destroy (Boss Galaga: 2). - `width: number` — Hit-box width. - `height: number` — Hit-box height. - `dives: string[]` — Dive program names; one is chosen per dive (seeded). - `loopDives?: string[]` — Dive programs used from `loopFromStage` on (bees start looping). - `loopFromStage?: number` — First stage that may use `loopDives`. - `escorts?: { kind: string; max: number }` — Escort kind and count this kind takes on a dive (boss: two butterflies). - `captures?: boolean` — This kind may carry out capture dives. ### `GalagaPhase` ```ts type GalagaPhase = | "waiting" | "flying" | "leaving" | "homing" | "formation" | "beaming" | "pulled" | "riding" | "rescuing" | "dead" | "gone" ``` Where an enemy is in its life: waiting to enter, flying a program, leaving the screen, flying home, in formation, beaming, a captured ship being pulled up, riding its boss, a rescued ship descending, dead or gone. ### `GalagaPresetOptions` ```ts interface GalagaPresetOptions ``` Options for {@link galagaPreset}. - `rows?: GalagaRow[]` — Custom rows, top first (default: 4 bosses, 2x8 butterflies, 2x10 bees). - `groupSize?: number` — Members per entry group for custom rows (default 8). - `lives?: number` — Starting fighters, including the one in play (3 = classic). - `capture?: boolean` — Boss tractor beams and captured-fighter rescue. - `challengingFirst?: number | null` — First challenging stage (null for none) and the interval after it. - `challengingEvery?: number` — Stages between challenging stages after the first (4 = classic). - `aggression?: number` — Multiplies dive frequency and simultaneous divers (1 = classic). - `maxShots?: number` — Simultaneous single-fighter missiles (2 = classic). - `extraLives?: number[]` — Scores that award an extra fighter (classic 20,000 and 70,000). - `extraEvery?: number` — After the listed scores, another fighter every this many points (classic 70,000; 0 = none). - `seed?: number` — Seed for dive selection and capture chance. ### `GalagaRow` ```ts interface GalagaRow ``` A formation row: `count` enemies of `kind`, centred on the grid. - `kind: string` — Enemy kind id for every ship in the row. - `count: number` — Ships in the row. ### `GalagaShot` ```ts interface GalagaShot ``` A missile or enemy bullet. - `id: number` — Stable id for drawing. - `x: number` — Centre x. - `y: number` — Top y for missiles, centre y for bullets. - `vx: number` — Velocity x (px/s). - `vy: number` — Velocity y (px/s). ### `GalagaSlot` ```ts interface GalagaSlot ``` A formation slot on the grid. - `id: string` — Unique slot id; also the enemy's id in normal stages. - `kind: string` — Kind that fills the slot. - `col: number` — Grid column (fractions allowed for centred rows). - `row: number` — Grid row, 0 at the top. ### `GalagaState` ```ts interface GalagaState ``` Serializable game state; read it through `state`. - `time: number` — Seconds since the game began. - `stage: number` — Stage number, from 1. - `challenging: boolean` — This stage is a challenging stage. - `challengeIndex: number` — Challenging stages begun so far, minus one. - `status: GalagaStatus` — Game status. - `statusTime: number` — Seconds in the current status. - `stageTime: number` — Seconds of play in this stage. - `score: number` — Score. - `lives: number` — Fighters left, including the one in play. - `extraAwarded: number` — Extra fighters awarded so far. - `player: { x: number; alive: boolean; dual: boolean; deadTime: number; captured: boolean; pendingDual: boolean; }` — The fighter: x, alive, dual, death timer, captured and a rescue waiting for respawn. - `enemies: GalagaEnemy[]` — Every enemy of the stage, and any captured fighter. - `playerShots: GalagaShot[]` — Missiles in flight. - `enemyShots: GalagaShot[]` — Enemy bullets in flight. - `fireHeld: boolean` — Fire was held on the last step (release rule). - `entryDone: boolean` — Every entering enemy has arrived or died. - `breatheTime: number` — Seconds of breathing. - `attackClock: number` — Seconds since the last dive launch. - `side: number` — Side of the next dive (-1 left, 1 right). - `hits: number` — Challenging-stage hits. - `total: number` — Enemies in this stage. - `groupHits: number[]` — Hits per entry group. - `groupSizes: number[]` — Members per entry group. - `lastBonus: number` — Last challenging-stage bonus. - `perfect: boolean` — The last challenging stage was perfect. - `nextId: number` — Next shot/captive id. - `random: number[]` — The kernel generator's state (four words from `createRng`), advanced in place, so a snapshot carries the stream. ### `GalagaStatus` ```ts type GalagaStatus = | "intro" | "playing" | "clear" | "result" | "game-over" ``` Stage intro banner, play, cleared, challenging-stage result, or game over. ### `Ramp` ```ts interface Ramp ``` A value that changes with the stage: `base + perStage * (stage - 1)`, clamped to `min`/`max`. - `base: number` — Value at stage 1. - `perStage?: number` — Change per stage after the first. - `min?: number` — Lower clamp. - `max?: number` — Upper clamp. --- ## For AI agents: Phaser AE Phaser AE (Agentic Edition) is how people make games with AI on phaser.io. 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