Top-down 2D game

// oxlint-disable no-underscore-dangle -- `window.__ignifxReady` is a test hook, and the double// underscore is what says it is not part of the game's API. The visual suite reads it by name.import { AUDIO_ASSET_TYPE, AUDIO_BUSES_ASSET_TYPE, AudioSource } from "@ignifx/audio";import { createApp, isIgnifxError, Vec2 } from "@ignifx/core";import { INPUT_ACTIONS_ASSET_TYPE } from "@ignifx/input";import { I18N_ASSET_TYPE } from "@ignifx/ui";// Vite virtual modules the plugins serve, typed by `@ignifx/vite-plugin/client` and// `@ignifx/editor-host/client`.import { attachEditorPlayControls } from "virtual:ignifx/editor";import { manifest } from "virtual:ignifx/manifest";import { acceptHotReload, scripts } from "virtual:ignifx/scripts";import { extensions } from "./extensions.js";import { installFrameTimeProbe } from "./frame-time-probe.js";import { createGameUi, hasTouch } from "./game-ui.js";import { installGameplayProbe } from "./gameplay-probe.js";import { createGameMenus } from "./menus/game-menus.js";import { applySettings, loadInputOverrides, loadSettings } from "./menus/settings-store.js";import { createRun } from "./run.js";import { scriptType } from "./script-types.js";import type { GameMenus } from "./menus/game-menus.js";import type { GraphicsHooks } from "./menus/settings-store.js";import type { Run } from "./run.js";// Types only: they are erased before the dev server sees this file, so no script module joins the// entry's graph and an edit to one hot-patches it instead of reloading the page (`script-types.ts`).import type { HudLine } from "./scripts/hud-line.js";import type { MenuController } from "./scripts/menu-controller.js";import type { PlayerController } from "./scripts/player-controller.js";import type { SaveGame } from "./scripts/save-game.js";import type { Shrine } from "./scripts/shrine.js";import type { AudioBusesAsset, AudioClip } from "@ignifx/audio";import type { App, AssetHandle, Entity } from "@ignifx/core";import type { InputActionsAsset } from "@ignifx/input";import type { LocaleAsset } from "@ignifx/ui";/** * A top-down 2D game: a tilemap with a collision layer, a Y-sorted layer of props and a character, * a dead-zoned camera follow, shrines to light, a title screen, a pause menu, a settings screen * with interactive rebinding, and a save file. * * The level is data: `assets/scenes/main.scene.json` holds every entity, component and reference, * and this file loads it. The shape of this file is the shape of every ignifx game: * * 1. `createApp` with `extensions()` from `./extensions.ts`; `ignifx.config.ts` carries the settings. * 2. Register the scripts from `virtual:ignifx/scripts`, accept hot reloads, and hand the app to *    the ignifx editor's play controls. * 3. Load what the scene's scripts read while it loads (input actions, audio buses), then the *    scene itself. **Await it before `app.start()`**: a load awaited before the loop runs settles as *    soon as it finishes; once the loop is running, delivery waits for a `PreUpdate`. * 4. The post-load steps a scene file cannot express — the README's "The level" lists them. * 5. `app.start()`. * * ## Query flags * * - `?static=1` stops the clock before the first frame and leaves the front end out, so the picture *   is exactly the authored scene and nothing depends on how long a frame took. It is what the *   visual golden suite in `tests/visual/` opens. * - `?hud=1` keeps the DOM overlay visible in a `?static=1` scene, which is what the gallery *   capture script uses; a golden leaves it off so the image never depends on how the runner draws *   a system font. * - `?probe=1` installs `window.__ignifxGameplay`, the read-only test hook the gameplay half of *   `tests/visual/tests/templates.spec.ts` measures the character with. See `src/gameplay-probe.ts`. * - `?locale=<tag>` picks a locale from `assets/strings.i18n.json` before the menus are built. */declare global {  interface Window {    /** Resolves once the game has presented a settled frame. See the module comment. */    __ignifxReady: Promise<AppStatus>;  }}/** What `window.__ignifxReady` resolves to. */type AppStatus = "ready" | "unsupported";/** The level, by its asset address. */const MAIN_SCENE = "scenes/main.scene.json";/** How many animation frames the scene is given before the image is called settled. */const SETTLE_FRAMES = 12;/** Explicit loader types for the template assets. */const ACTIONS = { type: INPUT_ACTIONS_ASSET_TYPE } as const;const CLIP = { type: AUDIO_ASSET_TYPE } as const;const BUSES = { type: AUDIO_BUSES_ASSET_TYPE } as const;const STRINGS = { type: I18N_ASSET_TYPE } as const;/** The sounds, which stay out of the scene file: each one is optional (see `clipOrNull`). */interface Sounds {  readonly pickup: AssetHandle<AudioClip>;  readonly footstep: AssetHandle<AudioClip>;  readonly uiClick: AssetHandle<AudioClip>;  readonly uiHover: AssetHandle<AudioClip>;  readonly ambient: AssetHandle<AudioClip>;}/** The entities of the loaded scene that the code below wires up. */interface World {  /** The character. */  readonly player: Entity;  /** The camera that follows it. */  readonly camera: Entity;  /** Where the character starts: wherever the scene puts it. */  readonly spawn: Vec2;  /** Every shrine in the scene, in scene order. */  readonly shrines: readonly Shrine[];}function noop(): void {  // Nothing to do: the promise executor runs synchronously and replaces this on the next line.}let announceReady: (status: AppStatus) => void = noop;window.__ignifxReady = new Promise<AppStatus>((resolve) => {  announceReady = resolve;});function nextFrame(): Promise<void> {  return new Promise<void>((resolve) => {    requestAnimationFrame(() => {      resolve();    });  });}/** * Waits for several animation frames, so a newly built scene has presented. * * @param frames - How many frames to wait for. * @returns A promise that resolves after the last of them. */function settle(frames: number): Promise<void> {  let chain = Promise.resolve();  for (let index = 0; index < frames; index += 1) {    chain = chain.then(nextFrame);  }  return chain;}/** * The clip behind a handle, or `null` when the browser refused to decode it. * * @remarks * `AssetHandle.value` is only meaningful once the handle is `"loaded"`; every sound in this * template is optional, so a failed decode costs the game that sound and nothing else. * * @param handle - The handle to read. * @returns The clip, or `null`. */function clipOrNull(handle: AssetHandle<AudioClip>): AudioClip | null {  return handle.state === "loaded" ? handle.value : null;}/** Swaps the canvas for the "no WebGPU here" panel in `index.html`. */function showUnsupported(): void {  document.body.dataset["webgpu"] = "unavailable";}/** * Finds an entity of the loaded scene by name. * * @param app - The running app. * @param name - The entity's name in `assets/scenes/main.scene.json`. * @returns The entity. * @throws Error when the scene has no entity of that name. */function requireEntity(app: App, name: string): Entity {  const entity = app.world.findByName(name);  if (entity === null) {    throw new Error(`${MAIN_SCENE} has no entity named "${name}".`);  }  return entity;}/** * Wires up the loaded scene: the optional sounds, and the entities the front end needs. * * @param app - The app the scene was loaded in. * @param sounds - The sounds that decoded, and the ones that did not. * @returns The character, the camera, the spawn point and the shrines. */function prepareWorld(app: App, sounds: Sounds): World {  const player = requireEntity(app, "Player");  // The clips are handed over rather than loaded inside the scripts, so a script that is  // hot-reloaded does not re-request a file the asset service has already delivered.  if (clipOrNull(sounds.footstep) !== null) {    player.requireComponent(scriptType<PlayerController>(app, "topdown/PlayerController")).footstep = sounds.footstep;  }  const shrines = app.world.components(scriptType<Shrine>(app, "topdown/Shrine"));  for (const shrine of shrines) {    if (clipOrNull(sounds.pickup) !== null) {      shrine.clip = sounds.pickup;    }  }  const here = player.transform.position2D;  return {    player,    camera: requireEntity(app, "Main Camera"),    spawn: new Vec2(here.x, here.y),    shrines: [...shrines],  };}/** * Builds the front end and the save file over a world that is already standing. * * @param app - The running app. * @param sounds - The sounds that decoded, and the ones that did not. * @param world - What {@link prepareWorld} found. * @param hud - The HUD element, or `null` under an app with no DOM overlay. * @param isBench - Whether the frame-time harness is driving, in which case the game starts *   immediately instead of waiting on a title screen. * @returns A promise that answers with the run once the front end is up. */async function installFrontEnd(  app: App,  sounds: Sounds,  world: World,  hud: HTMLDivElement | null,  isBench: boolean,): Promise<Run> {  // A 2D sprite scene has no shadow-casting light and no post-process chain, so the settings  // screen leaves both graphics rows out rather than offering a switch that does nothing.  const graphics: GraphicsHooks = {    supportsShadows: false,    supportsPostProcessing: false,    setShadows: (): void => {      // No shadows in a sprite scene.    },    setPostProcessing: (): void => {      // No post-process chain in a sprite scene.    },  };  await loadInputOverrides(app);  const settings = await loadSettings(app, app.i18n.locale);  applySettings(app, settings, graphics);  const host = app.world.createEntity("Game UI");  const saveGame = host.addComponent(scriptType<SaveGame>(app, "topdown/SaveGame"));  let menus: GameMenus | null = null;  const run = createRun(world.player, world.shrines, world.spawn, (): void => {    if (saveGame.checkpoint()) {      menus?.toast(app.i18n.t("toast.checkpoint"));    }  });  saveGame.run = run.state;  menus = createGameMenus(app, {    settings,    graphics,    gameplayMap: "Player",    rebindable: [      { action: "interact", labelKey: "action.interact" },      { action: "pause", labelKey: "action.pause" },    ],    creditKeys: ["credits.engine", "credits.art", "credits.license"],    sounds: { click: clipOrNull(sounds.uiClick), hover: clipOrNull(sounds.uiHover) },    onStartNew: (): void => {      saveGame.restart();    },    onContinue: (save): void => {      saveGame.restore(save);    },    onSaveNow: (): Promise<boolean> => saveGame.save(),    onQuitToTitle: (): void => {      saveGame.restart();    },  });  host.addComponent(scriptType<MenuController>(app, "topdown/MenuController")).menus = menus;  const line = host.addComponent(scriptType<HudLine>(app, "topdown/HudLine"));  line.element = hud;  line.render = (): string => app.i18n.t("hud.status", { score: run.score() });  // `interact` runs a shape query and now says what it found, because a control the player is told  // to press has to do something the player can see.  const controller = world.player.getComponent(scriptType<PlayerController>(app, "topdown/PlayerController"));  if (controller !== null) {    controller.onLookAround = (names: readonly string[]): void => {      menus.toast(        names.length === 0          ? app.i18n.t("toast.nothingNearby")          : app.i18n.t("toast.nearby", { names: names.join(", ") }),      );    };  }  // The ambient pad loops on the `Music` bus, which `game.audio.json` marks as not pausable so the  // menus can duck it rather than silence it.  if (clipOrNull(sounds.ambient) !== null) {    app.world.createEntity("Ambience").addComponent(AudioSource, {      clip: sounds.ambient,      bus: "Music",      loop: true,      playOnAwake: true,      volume: 0.9,    });  }  if (isBench) {    // The frame-time harness measures a *running* game, so it skips the title screen. Everything    // else is the scene a player gets.    return run;  }  // The game boots into its title screen. `MenuController` reconciles `app.pause()` against the  // screen stack every frame, so this one call is what stops the world until "New game".  menus.show("title");  app.pause();  return run;}async function main(): Promise<AppStatus> {  const canvas = document.querySelector("#game");  if (!(canvas instanceof HTMLCanvasElement)) {    throw new Error('2d-topdown needs a <canvas id="game"> element on the page.');  }  const flags = new URLSearchParams(window.location.search);  const isStatic = flags.get("static") === "1";  const isBench = flags.get("bench") === "1";  const showOverlay = (!isStatic || flags.get("hud") === "1") && !isBench;  let app: App;  try {    app = await createApp({      canvas,      settings: import.meta.env.IGNIFX_CONFIG,      // The address-to-URL table `@ignifx/vite-plugin` built from `assets/`. Importing the virtual      // module rather than fetching `assets.manifest.json` means the table is in the bundle, so      // the first asset request needs no round trip.      assets: { manifest },      extensions: extensions(),    });  } catch (error) {    // IGX-0701 is the one failure a shipped game must handle itself: the browser has no WebGPU and    // ignifx has no fallback renderer by decision (ADR-0001).    if (isIgnifxError(error) && error.code === "IGX-0701") {      showUnsupported();      return "unsupported";    }    throw error;  }  // Every class under `src/scripts/**` with a `static typeId`, from the plugin's virtual registry. It  // is the only way code reaches a script: the scene names them by `typeId`, and so does  // `scriptType`. In development the registry hot-reloads edited scripts through `app.hotReload`  // (`"patch"` by default).  app.registerComponents(scripts);  acceptHotReload(app);  // Under `vite dev`, lets the ignifx editor's play view play, pause, step and stop this app. In a  // production build it is an empty function (`vite.config.ts`).  attachEditorPlayControls(app);  // The strings come first and alone: every label below is read out of them, and the document is  // under three kilobytes, so nothing is gained by making the loading screen wait for it.  const strings = app.assets.load<LocaleAsset>("strings.i18n.json", STRINGS);  await strings.promise;  await app.i18n.load(strings);  const locale = flags.get("locale");  if (locale !== null && app.i18n.availableLocales.includes(locale)) {    app.i18n.locale = locale;  }  // The overlay comes up before the first asset is requested, so the loading bar sees every byte.  const gameUi = createGameUi(app, {    loadingLabel: app.i18n.t("loading.label"),    buttons: [{ control: "interact", label: "E", ariaLabel: app.i18n.t("action.interact") }],    moveLabel: app.i18n.t("action.move"),    pauseLabel: app.i18n.t("action.pause"),    touch: !isStatic && hasTouch(),  });  app.ui.visible = showOverlay;  const sounds: Sounds = {    pickup: app.assets.load<AudioClip>("pickup.wav", CLIP),    footstep: app.assets.load<AudioClip>("footstep.wav", CLIP),    uiClick: app.assets.load<AudioClip>("ui-click.wav", CLIP),    uiHover: app.assets.load<AudioClip>("ui-hover.wav", CLIP),    ambient: app.assets.load<AudioClip>("ambient.wav", CLIP),  };  const actions = app.assets.load<InputActionsAsset>("game.input.json", ACTIONS);  const buses = app.assets.load<AudioBusesAsset>("game.audio.json", BUSES);  await Promise.all([actions.promise, buses.promise]);  // The clips are awaited together and separately from the rest: a browser that refuses to decode  // a sound should cost the game its audio, not its first frame.  await Promise.all(    Object.values(sounds).map(async (handle: AssetHandle<AudioClip>): Promise<void> => {      await handle.promise.catch((error: unknown) => {        app.log.warn("a sound could not be decoded: {error}", String(error));      });    }),  );  // Installed here rather than through `input.actions` in `ignifx.config.ts`, so that the maps  // exist before the scene loads: `PlayerController` resolves its action names in `awake`, which  // runs while `loadScene` builds it.  app.input.loadActions(actions.value);  await app.audio.buildBuses(buses.value.buses);  // The level: the loader fetches every atlas, clip set and tilemap the file names before it builds  // an entity, so each still sprite draws the frame its `frameName` names from the first frame.  await app.world.loadScene(MAIN_SCENE);  const world = prepareWorld(app, sounds);  if (isStatic) {    // Stopping the clock *before* `start()` means no fixed step ever runs, so nothing falls,    // nothing animates and the camera never chases: the frame is exactly what was authored. The    // front end is left out for the same reason.    app.time.timeScale = 0;  } else {    const run = await installFrontEnd(app, sounds, world, gameUi.hud, isBench);    // A read-only test hook, and only under `?probe=1`: the gameplay half of the template spec    // measures the character in metres rather than in pixels. See `src/gameplay-probe.ts`.    if (flags.get("probe") === "1") {      installGameplayProbe(app, world.player, world.camera, world.shrines, run);    }  }  if (isStatic && showOverlay && gameUi.hud !== null) {    // `?static=1` leaves the front end out, so nothing writes the HUD. `?hud=1` says the overlay is    // wanted anyway — the gallery capture asks for exactly that — so the zero state is written once.    gameUi.hud.textContent = app.i18n.t("hud.status", { score: 0 });  }  gameUi.loading.hide();  if (isBench) {    installFrameTimeProbe(app);  }  await app.start();  await settle(SETTLE_FRAMES);  app.log.info("2d-topdown running; sprites:", app.twoD.spriteCount);  return "ready";}void main().then(announceReady, (error: unknown) => {  showUnsupported();  announceReady("unsupported");  // Rethrown out of the promise chain so it reaches `window.onerror` as an uncaught error rather  // than a swallowed rejection. Templates never log through `console` (coding standards §6).  setTimeout(() => {    throw error;  }, 0);});