ABout to try scene and script merger

types/asset/assetbatch.d.ts

@@ -0,0 +1,86 @@
+/**
+ * Copyright (c) 2026 Dominic Masters
+ *
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+/**
+ * Descriptor for one entry in an `AssetBatch`.
+ *
+ * `format`  — texture format constant (`Texture.FORMAT_*`). Alias for `input`
+ *             when the type is `Asset.TYPE_TEXTURE`.
+ * `axis`    — mesh axis constant (`Asset.MESH_AXIS_*`). Alias for `input`
+ *             when the type is `Asset.TYPE_MESH`.
+ * `input`   — generic numeric input for all other loader types.
+ */
+interface AssetBatchDescriptor {
+  path: string;
+  type: number;
+  format?: number;
+  axis?: number;
+  input?: number;
+}
+
+/** A group of asset entries locked and queued for loading together. */
+interface AssetBatch {
+  /** Number of entries in the batch. */
+  readonly count: number;
+  /** `true` when every entry has reached `LOADED`. */
+  readonly isLoaded: boolean;
+  /** `true` if any entry is in an `ERROR` state. */
+  readonly hasError: boolean;
+  /**
+   * Blocks until every entry is loaded.
+   * Returns `this` for chaining.
+   * @throws If any entry fails to load.
+   */
+  requireLoaded(): this;
+  /**
+   * Acquires one additional lock on every entry.
+   * Returns `this` for chaining.
+   */
+  lock(): this;
+  /**
+   * Releases all locks and clears the batch.
+   * After this call the object is invalid — do not use it again.
+   */
+  unlock(): void;
+  /**
+   * Returns the `AssetEntry` at `index`, adding an independent lock.
+   * The returned entry must be unlocked separately when no longer needed.
+   * Returns `undefined` if `index` is out of range or the batch is disposed.
+   */
+  entry(index: number): AssetEntry | undefined;
+
+  /**
+   * Fires once when every entry has loaded successfully.
+   * Subscribe with `onLoaded[0] = () => { ... }`.
+   */
+  readonly onLoaded: AssetEventProxy;
+  /**
+   * Fires each time a single entry finishes loading.
+   * Subscribe with `onEntryLoaded[0] = () => { ... }`.
+   */
+  readonly onEntryLoaded: AssetEventProxy;
+  /**
+   * Fires once when all entries have finished but at least one errored.
+   * Subscribe with `onError[0] = () => { ... }`.
+   */
+  readonly onError: AssetEventProxy;
+  /**
+   * Fires each time a single entry transitions to an error state.
+   * Subscribe with `onEntryError[0] = () => { ... }`.
+   */
+  readonly onEntryError: AssetEventProxy;
+
+  toString(): string;
+}
+
+interface AssetBatchConstructor {
+  /** Creates a batch from an array of descriptors. Works with or without `new`. */
+  (descriptors: AssetBatchDescriptor[]): AssetBatch;
+  new(descriptors: AssetBatchDescriptor[]): AssetBatch;
+}
+
+declare var AssetBatch: AssetBatchConstructor;

types/asset/assetentry.d.ts

@@ -5,6 +5,24 @@
  * https://opensource.org/licenses/MIT
  */
 
+/**
+ * An array-like proxy over one of an asset entry's events.
+ * Assign a function to a numbered slot to subscribe; assign `null` to
+ * unsubscribe that slot.
+ *
+ * @example
+ * entry.onLoaded[0] = () => Console.print('loaded!');
+ * entry.onLoaded[0] = null; // unsubscribe
+ */
+interface AssetEventProxy {
+  readonly length: number;
+  0: (() => void) | null;
+  1: (() => void) | null;
+  2: (() => void) | null;
+  3: (() => void) | null;
+  toString(): string;
+}
+
 /**
  * A live reference to an entry in the asset cache.
  * Holds a lock that keeps the entry alive; the lock is released automatically
@@ -26,6 +44,12 @@ interface AssetEntry {
    * is not yet loaded.
    */
   readonly texture: Texture | undefined;
+  /** Event proxy — subscribe up to 4 callbacks for when loading completes. */
+  readonly onLoaded: AssetEventProxy;
+  /** Event proxy — subscribe up to 4 callbacks for when the entry is disposed. */
+  readonly onUnloaded: AssetEventProxy;
+  /** Event proxy — subscribe up to 4 callbacks for when loading fails. */
+  readonly onError: AssetEventProxy;
   /**
    * Blocks until the entry reaches `LOADED` (or `ERROR`).
    * Returns `this` for chaining.