Add Wuzhang finale and lazy unit loading

src/game/data/unitAssets.ts

@@ -0,0 +1,127 @@
+import Phaser from 'phaser';
+
+export type UnitDirection = 'south' | 'east' | 'north' | 'west';
+
+const unitWalkFrameCount = 4;
+export const unitSheetFrameSize = 313;
+const unitWalkFrameRate = 8;
+const unitIdleFrameRate = 4;
+
+const unitSheetRows: Record<UnitDirection, number> = {
+  south: 0,
+  east: 1,
+  north: 2,
+  west: 3
+};
+
+type UnitSheetAsset = {
+  key: string;
+  url: string;
+  actionKey: string;
+  actionUrl: string;
+};
+
+const unitSheetModules = import.meta.glob('../../assets/images/units/unit-*.png', {
+  eager: true,
+  import: 'default'
+}) as Record<string, string>;
+
+function textureKeyFromPath(path: string) {
+  const fileName = path.split('/').pop() ?? path;
+  return fileName.replace(/\.png$/i, '');
+}
+
+const unitSheetUrls = Object.fromEntries(
+  Object.entries(unitSheetModules).map(([path, url]) => [textureKeyFromPath(path), url])
+);
+
+const unitSheets = Object.entries(unitSheetUrls)
+  .filter(([key]) => !key.endsWith('-actions'))
+  .map(([key, url]) => ({
+    key,
+    url,
+    actionKey: `${key}-actions`,
+    actionUrl: unitSheetUrls[`${key}-actions`]
+  }))
+  .filter((sheet): sheet is UnitSheetAsset => Boolean(sheet.actionUrl))
+  .sort((left, right) => left.key.localeCompare(right.key));
+
+const unitSheetAssetsByKey = new Map(unitSheets.map((sheet) => [sheet.key, sheet]));
+
+export function unitTextureVariantKeys(baseKey: string) {
+  const prefix = `${baseKey}-`;
+  const keys = unitSheets
+    .map((sheet) => sheet.key)
+    .filter((key) => key === baseKey || key.startsWith(prefix))
+    .sort();
+
+  return keys.length > 0 ? keys : [baseKey];
+}
+
+export function loadUnitSheets(scene: Phaser.Scene, keys: Iterable<string>, onReady: () => void) {
+  const uniqueKeys = Array.from(new Set(keys));
+  const missingSheets = uniqueKeys
+    .filter((key) => !scene.textures.exists(key) || !scene.textures.exists(`${key}-actions`))
+    .map((key) => unitSheetAssetsByKey.get(key) ?? missingUnitSheet(key));
+
+  if (missingSheets.length <= 0) {
+    onReady();
+    return;
+  }
+
+  scene.load.once('complete', onReady);
+  missingSheets.forEach(({ key, url, actionKey, actionUrl }) => {
+    if (!scene.textures.exists(key)) {
+      scene.load.spritesheet(key, url, {
+        frameWidth: unitSheetFrameSize,
+        frameHeight: unitSheetFrameSize
+      });
+    }
+    if (!scene.textures.exists(actionKey)) {
+      scene.load.spritesheet(actionKey, actionUrl, {
+        frameWidth: unitSheetFrameSize,
+        frameHeight: unitSheetFrameSize
+      });
+    }
+  });
+  scene.load.start();
+}
+
+export function ensureUnitAnimations(scene: Phaser.Scene, keys: Iterable<string>) {
+  Array.from(new Set(keys)).forEach((key) => {
+    if (!scene.textures.exists(key)) {
+      return;
+    }
+
+    (['south', 'east', 'north', 'west'] as UnitDirection[]).forEach((direction) => {
+      const frames = Array.from({ length: unitWalkFrameCount }, (_, frameIndex) => ({
+        key,
+        frame: unitSheetRows[direction] * unitWalkFrameCount + frameIndex
+      }));
+      const walkAnimationKey = `${key}-walk-${direction}`;
+      const idleAnimationKey = `${key}-idle-${direction}`;
+
+      if (!scene.anims.exists(walkAnimationKey)) {
+        scene.anims.create({
+          key: walkAnimationKey,
+          frames,
+          frameRate: unitWalkFrameRate,
+          repeat: -1
+        });
+      }
+
+      if (!scene.anims.exists(idleAnimationKey)) {
+        scene.anims.create({
+          key: idleAnimationKey,
+          frames,
+          frameRate: unitIdleFrameRate,
+          repeat: -1
+        });
+      }
+    });
+  });
+}
+
+function missingUnitSheet(key: string): never {
+  throw new Error(`Missing unit sheet asset for ${key}`);
+}