/// <reference types="webxr" />
import { Component, ComponentConstructor, Object as Object3D, Physics, I18N, MorphTargets, Font, ParticleEffect } from './wonderland.js';
import { Emitter, RetainEmitter } from './utils/event.js';
import { Version } from './version.js';
import { WASM } from './wasm.js';
import { Logger } from './utils/logger.js';
import { MaterialManager } from './resources/material-manager.js';
import { MeshManager } from './resources/mesh-manager.js';
import { ResourceManager } from './resources/resource.js';
import { TextureManager } from './resources/texture-manager.js';
import { ImageLike, ProgressCallback } from './types.js';
import { XRSessionState, WebXR } from './webxr.js';
import { Prefab, InMemoryLoadOptions, LoadOptions } from './prefab.js';
import { Scene, ActivateOptions } from './scene.js';
import { PrefabGLTF, GLTFOptions } from './scene-gltf.js';
/**
 * Ensures that this API is compatible with the given
 * runtime version.
 *
 * We only enforce compatibility for major and minor components, i.e.,
 * the runtime and the API must both be of the form `x.y.*`.
 *
 * @throws If the major or the minor components are different.
 *
 * @param version The target version
 */
export declare function checkRuntimeCompatibility(version: Version): void;
/**
 * Main Wonderland Engine instance.
 *
 * Controls the canvas, rendering, and JS <-> WASM communication.
 */
export declare class WonderlandEngine {
    #private;
    /**
     * {@link Emitter} for WebXR session end events.
     *
     * Usage from within a component:
     *
     * ```js
     * this.engine.onXRSessionEnd.add(() => console.log("XR session ended."));
     * ```
     */
    get onXRSessionEnd(): Emitter;
    /**
     * {@link RetainEmitter} for WebXR session start events.
     *
     * Usage from within a component:
     *
     * ```js
     * this.engine.onXRSessionStart.add((session, mode) => console.log(session, mode));
     * ```
     *
     * By default, this emitter is retained and will automatically call any callback added
     * while a session is already started:
     *
     * ```js
     * // XR session is already active.
     * this.engine.onXRSessionStart.add((session, mode) => {
     *     console.log(session, mode); // Triggered immediately.
     * });
     * ```
     */
    get onXRSessionStart(): Emitter<[XRSession, XRSessionMode]>;
    /**
     * {@link Emitter} for canvas / main framebuffer resize events.
     *
     * Usage from within a component:
     *
     * ```js
     * this.engine.onResize.add(() => {
     *     const canvas = this.engine.canvas;
     *     console.log(`New Size: ${canvas.width}, ${canvas.height}`);
     * });
     * ```
     *
     * @note The size of the canvas is in physical pixels, and is set via {@link WonderlandEngine.resize}.
     */
    readonly onResize: Emitter;
    /** Whether AR is supported by the browser. */
    get arSupported(): boolean;
    /** Whether VR is supported by the browser. */
    get vrSupported(): boolean;
    /**
     * {@link RetainEmitter} signalling the end of the loading screen.
     *
     * Listeners get notified when the first call to {@link Scene#load()} is
     * invoked. At this point the new scene has not become active, and none of
     * its resources or components are initialized.
     *
     * Compared to {@link onSceneLoaded}, this does not wait for all components
     * to be fully initialized and activated. Any handler added inside
     * {@link Component#init()}, {@link Component#start()} or
     * {@link Component#onActivate()} will be called immediately.
     *
     * Usage:
     *
     * ```js
     * this.engine.onLoadingScreenEnd.add(() => console.log("Wait is over!"));
     * ```
     */
    readonly onLoadingScreenEnd: RetainEmitter<void[]>;
    /**
     * {@link Emitter} for scene loaded events.
     *
     * Listeners get notified when a call to {@link Scene#load()} finishes. At
     * this point all resources are loaded and all components had their
     * {@link Component#init()} as well as (if active)
     * {@link Component#start()} and {@link Component#onActivate()} methods
     * called.
     *
     * Usage from within a component:
     *
     * ```js
     * this.engine.onSceneLoaded.add(() => console.log("Scene switched!"));
     * ```
     *
     * @deprecated Use {@link onSceneActivated} instead.
     */
    readonly onSceneLoaded: Emitter<void[]>;
    /**
     * {@link Emitter} for scene activated events.
     *
     * This listener is notified with the old scene as first parameter, and
     * the new scene as second.
     *
     * This listener is notified after all resources are loaded and all components had their
     * {@link Component#init()} as well as (if active)
     * {@link Component#start()} and {@link Component#onActivate()} methods
     * called.
     *
     * Usage from within a component:
     *
     * ```js
     * this.engine.onSceneActivated.add((oldScene, newScene) => {
     *     console.log(`Scene switch from ${oldScene.filename} to ${newScene.filename}`);
     * });
     * ```
     */
    readonly onSceneActivated: Emitter<[Scene, Scene]>;
    /**
     * Triggered when a hot reload is requested.
     *
     * When using the Wonderland Editor, this will be triggered when packaging
     * the project.
     *
     * @note When {@link autoHotReload} is `true`, the emitter is notified after the
     * scene is reloaded.
     *
     * To customize the hot reload behavior, set the {@link autoHotReload} to `false`,
     * and use this emitter:
     *
     * ```js
     * this.engine.onHotReloadRequest.add(async (filename: string) => {
     *     // This handler can be used to re-download a scene, download components,
     *     // fetch an API, anything!
     *     await this.loadMainScene(filename);
     * });
     * ```
     */
    readonly onHotReloadRequest: Emitter<[string]>;
    /**
     * Access to internationalization.
     */
    readonly i18n: I18N;
    /**
     * WebXR related state, `null` if no XR session is active.
     */
    get xr(): XRSessionState | null;
    /**
     * If `true`, {@link Texture}, {@link Object3D}, and {@link Component}
     * instances have their prototype erased upon destruction.
     *
     * #### Object
     *
     * ```js
     * engine.erasePrototypeOnDestroy = true;
     *
     * const obj = engine.scene.addObject();
     * obj.name = 'iamalive';
     * console.log(obj.name); // Prints 'iamalive'
     *
     * obj.destroy();
     * console.log(obj.name); // Throws an error
     * ```
     *
     * #### Component
     *
     * Components will also be affected:
     *
     * ```js
     * class MyComponent extends Component {
     *     static TypeName = 'my-component';
     *     static Properties = {
     *         alive: Property.bool(true)
     *     };
     *
     *     start() {
     *         this.destroy();
     *         console.log(this.alive) // Throws an error
     *     }
     * }
     * ```
     *
     * A component is also destroyed if its ancestor gets destroyed:
     *
     * ```js
     * class MyComponent extends Component {
     *     ...
     *     start() {
     *         this.object.parent.destroy();
     *         console.log(this.alive) // Throws an error
     *     }
     * }
     * ```
     *
     * @note Native components will not be erased if destroyed via object destruction:
     *
     * ```js
     * const mesh = obj.addComponent('mesh');
     * obj.destroy();
     * console.log(mesh.active) // Doesn't throw even if the mesh is destroyed
     * ```
     *
     * @since 1.1.1
     */
    erasePrototypeOnDestroy: boolean;
    /**
     * If `true`, the materials will be wrapped in a proxy to support pre-1.2.0
     * material access, i.e.,
     *
     * ```js
     * const material = new Material(engine, 'Phong Opaque');
     * material.diffuseColor = [1.0, 0.0, 0.0, 1.0];
     * ```
     *
     * If `false`, property accessors will not be available and material
     * properties should be accessed via methods, i.e.,
     *
     * ```js
     * const PhongOpaque = engine.materials.getTemplate('Phong Opaque');
     * const material = new PhongOpaque();
     * material.setDiffuseColor([1.0, 0.0, 0.0, 1.0]);
     * ...
     * const diffuse = material.getDiffuseColor();
     * ```
     *
     * When disabled, reading/writing to materials is slightly more efficient on the CPU.
     */
    legacyMaterialSupport: boolean;
    /**
     * If `true`, automatically reloads the scene sent by the editor socket.
     *
     * @note The {@link onHotReloadRequest} emitter is notified **after** the scene is re-loaded.
     *
     * To use custom hot-reload code, set this boolean to `false` and add the reloading code
     *
     */
    autoHotReload: boolean;
    /**
     * If `true`, uncompressed images will be automatically converted
     * to `ImageBitmap` before upload to the GPU.
     *
     * For more information, have a look at the
     * [ImageBitmap](https://developer.mozilla.org/en-US/docs/Web/API/ImageBitmap) documentation.
     */
    loadUncompressedImagesAsBitmap: boolean;
    /**
     * Scene cache in scene manager.
     *
     * @hidden
     */
    _scenes: (Prefab | null)[];
    /**
     * Currently active scene.
     *
     * @hidden
     */
    _scene: Scene;
    /** Incremented every time a new main scene is loaded. */
    _mainSceneVersion: number;
    /** @hidden */
    private _textures;
    /** @hidden */
    private _materials;
    /** @hidden */
    private _meshes;
    /** @hidden */
    private _morphTargets;
    /** @hidden */
    private _fonts;
    /** @hidden */
    private _particleEffects;
    /**
     * Current loading uncompressed images.
     *
     * @note Indexed by js image index.
     *
     * @hidden
     */
    private _uncompressedPromises;
    /**
     * Create a new engine instance.
     *
     * @param wasm Wasm bridge instance
     * @param loadingScreen Loading screen .bin file data
     *
     * @hidden
     */
    constructor(wasm: WASM, loadingScreen: ArrayBuffer | null, withRenderer: boolean);
    /**
     * Start the engine if it's not already running.
     *
     * When using the {@link loadRuntime} function, this method is called
     * automatically.
     */
    start(): void;
    /**
     * Register a custom JavaScript component type.
     *
     * You can register a component directly using a class inheriting from {@link Component}:
     *
     * ```js
     * import { Component, Type } from '@wonderlandengine/api';
     *
     * export class MyComponent extends Component {
     *     static TypeName = 'my-component';
     *     static Properties = {
     *         myParam: {type: Type.Float, default: 42.0},
     *     };
     *     init() {}
     *     start() {}
     *     update(dt) {}
     *     onActivate() {}
     *     onDeactivate() {}
     *     onDestroy() {}
     * });
     *
     * // Here, we assume we have an engine already instantiated.
     * // In general, the registration occurs in the `index.js` file in your
     * // final application.
     * engine.registerComponent(MyComponent);
     * ```
     *
     * {@label CLASSES}
     * @param classes Custom component(s) extending {@link Component}.
     *
     * @since 1.0.0
     */
    registerComponent(...classes: ComponentConstructor[]): void;
    /**
     * Register a component bundle
     *
     * The module must be of the form:
     *
     * ```js
     * export default function(engine) {
     *     engine.registerComponent(MyComponent);
     *     ...
     * }
     * ```
     *
     * Alternatively, you can manually register a component bundle:
     *
     * ```js
     * const registerBundle = (await import(url)).default;
     * registerBundle(engine);
     * ```
     *
     * @param url The URL of the module to register.
     * @param nocache If `true`, force browser to re-download the file.
     */
    registerBundle(url: string, nocache?: boolean): Promise<void>;
    /**
     * Update the loading screen progress bar.
     *
     * @param value Current loading percentage, in the range [0; 1].
     *
     * @since 1.2.1
     */
    setLoadingProgress(percentage: number): void;
    /**
     * Switch the current active scene.
     *
     * Once active, the scene will be updated and rendered on the canvas.
     *
     * The currently active scene is accessed via {@link WonderlandEngine.scene}:
     *
     * ```js
     * import {Component} from '@wonderlandengine/api';
     *
     * class MyComponent extends Component{
     *     start() {
     *         console.log(this.scene === this.engine.scene); // Prints `true`
     *     }
     * }
     * ```
     *
     * @note This method will throw if the scene isn't activatable.
     *
     * #### Component Lifecycle
     *
     * Marking a scene as active will:
     * * Call {@link Component#onDeactivate} for all active components of the previous scene
     * * Call {@link Component#onActivate} for all active components of the new scene
     *
     * #### Usage
     *
     * ```js
     * const scene = await engine.loadScene('Scene.bin');
     * engine.switchTo(scene);
     * ```
     *
     * @returns A promise that resolves once the scene is ready.
     *
     * @since 1.2.0
     */
    switchTo(scene: Scene, opts?: ActivateOptions): Promise<void>;
    /**
     * Load the scene from a URL, as the main scene of a new {@link Scene}.
     *
     * #### Usage
     *
     * ```js
     * // The method returns the main scene
     * const scene = await engine.loadMainScene();
     * ```
     *
     * #### Destruction
     *
     * Loading a new main scene entirely resets the state of the engine, and destroys:
     * - All loaded scenes, prefabs, and gltf files
     * - Meshes
     * - Textures
     * - Materials
     *
     * @note This method can only load Wonderland Engine `.bin` files.
     *
     * @param options The URL pointing to the scene to load or an object
     *     holding additional loading options.
     * @param progress Optional progress callback. When setting a custom
     *     callback, you need to manually call {@link setLoadingProgress} to
     *     get progress updates in the loading screen.
     * @returns The main scene of the new {@link Scene}.
     */
    loadMainScene(options: LoadOptions & ActivateOptions, progress?: ProgressCallback): Promise<Scene>;
    /**
     * Similar to {@link WonderlandEngine.loadMainScene}, but loading is done
     * from an `ArrayBuffer`.
     *
     * @param options An object containing the buffer and extra metadata.
     * @returns The main scene of the new {@link Scene}.
     */
    loadMainSceneFromBuffer(options: InMemoryLoadOptions & ActivateOptions): Promise<Scene>;
    /**
     * Load a {@link Prefab} from a URL.
     *
     * #### Usage
     *
     * ```js
     * const prefab = await engine.loadPrefab('Prefab.bin');
     * ```
     *
     * @note This method can only load Wonderland Engine `.bin` files.
     * @note This method is a wrapper around {@link WonderlandEngine.loadPrefabFromBuffer}.
     *
     * @param url The URL pointing to the prefab to load.
     * @param progress Optional progress callback.
     * @returns The loaded {@link Prefab}.
     */
    loadPrefab(options: LoadOptions, progress?: ProgressCallback): Promise<Prefab>;
    /**
     * Similar to {@link WonderlandEngine.loadPrefab}, but loading is done from
     * an `ArrayBuffer`.
     *
     * @param options An object containing the buffer and extra metadata.
     * @returns A new loaded {@link Prefab}.
     */
    loadPrefabFromBuffer(options: InMemoryLoadOptions): Prefab;
    /**
     * Load a scene from a URL.
     *
     * At the opposite of {@link WonderlandEngine.loadMainScene}, the scene loaded
     * will be added to the list of existing scenes, and its resources will be made
     * available for other scenes/prefabs/gltf to use.
     *
     * #### Resources Sharing
     *
     * Upon loading, the scene resources are added in the engine, and references
     * to those resources are updated.
     *
     * It's impossible for a scene loaded with this method to import pipelines.
     * Thus, the loaded scene will reference existing pipelines in the main scene,
     * based on their names.
     *
     * #### Usage
     *
     * ```js
     * const scene = await engine.loadScene('Scene.bin');
     * ```
     *
     * @note This method can only load Wonderland Engine `.bin` files.
     *
     * @param options The URL pointing to the scene to load or an object
     *     holding additional loading options.
     * @param progress Optional progress callback.
     * @returns A new loaded {@link Scene}.
     */
    loadScene(options: LoadOptions, progress?: ProgressCallback): Promise<Scene>;
    /**
     * Create a glTF scene from a URL.
     *
     * @note Loading glTF files requires `enableRuntimeGltf` to be checked in
     *     the editor Project Settings.
     *
     * @note This method is a wrapper around {@link WonderlandEngine.loadGLTFFromBuffer}.
     *
     * @param options The URL pointing to the scene to load or an object
     *     holding additional loading options, optionally including
     *     {@link GLTFOptions}. {@link LoadOptions.streamed} is ignored as
     *     streamed glTF parsing isn't supported.
     * @param progress Optional progress callback.
     * @returns A new loaded {@link PrefabGLTF}.
     */
    loadGLTF(opts: LoadOptions & GLTFOptions, progress?: ProgressCallback): Promise<PrefabGLTF>;
    /**
     * Similar to {@link WonderlandEngine.loadScene}, but loading is done from
     * an `ArrayBuffer`.
     *
     * @throws If the scene is streamable.
     *
     * @param options An object containing the buffer and extra metadata.
     * @returns A new loaded {@link Scene}.
     */
    loadSceneFromBuffer(options: InMemoryLoadOptions): Scene;
    /**
     * Similar to {@link WonderlandEngine.loadGLTF}, but loading is done from
     * an `ArrayBuffer`.
     *
     * @note Loading glTF files requires `enableRuntimeGltf` to be checked in
     *     the editor Project Settings.
     *
     * @param options An object containing the buffer and extra glTF metadata.
     * @returns A new loaded {@link PrefabGLTF}.
     */
    loadGLTFFromBuffer(options: InMemoryLoadOptions & GLTFOptions): PrefabGLTF;
    /**
     * Checks whether the given component is registered or not.
     *
     * @param typeOrClass A string representing the component typename (e.g., `'cursor-component'`),
     *     or a component class (e.g., `CursorComponent`).
     * @returns `true` if the component is registered, `false` otherwise.
     */
    isRegistered(typeOrClass: string | ComponentConstructor): boolean;
    /**
     * Retrieve the registered component from its type name.
     *
     * @param typename The component {@link Component.TypeName} property
     * @returns The class if a component was registered with given name, `null` otherwise.
     */
    getComponentClass<T extends Component>(typename: string): ComponentConstructor<T> | null;
    /**
     * Resize the canvas and the rendering context.
     *
     * @note The `width` and `height` parameters will be scaled by the
     * `devicePixelRatio` value. By default, the pixel ratio used is
     * [window.devicePixelRatio](https://developer.mozilla.org/en-US/docs/Web/API/Window/devicePixelRatio).
     *
     * @param width The width, in CSS pixels.
     * @param height The height, in CSS pixels.
     * @param devicePixelRatio The pixel ratio factor.
     */
    resize(width: number, height: number, devicePixelRatio?: number): void;
    /**
     * Run the next frame.
     *
     * @param fixedDelta The elapsed time between this frame and the previous one.
     *
     * @note The engine automatically schedules next frames. You should only
     * use this method for testing.
     */
    nextFrame(fixedDelta?: number): void;
    /**
     * Request an XR session.
     *
     * @note Please use this call instead of directly calling `navigator.xr.requestSession()`.
     * Wonderland Engine requires to be aware that a session is started, and this
     * is done through this call.
     *
     * @param mode The XR mode.
     * @param features An array of required features, e.g., `['local-floor', 'hit-test']`.
     * @param optionalFeatures An array of optional features, e.g., `['bounded-floor', 'depth-sensing']`.
     * @returns A promise resolving with the `XRSession`, a string error message otherwise.
     */
    requestXRSession(mode: XRSessionMode, features: string[], optionalFeatures?: string[]): Promise<XRSession>;
    /**
     * Offer an XR session.
     *
     * Adds an interactive UI element to the browser interface to start an XR
     * session. Browser support is optional, so it's advised to still allow
     * requesting a session with a UI element on the website itself.
     *
     * @note Please use this call instead of directly calling `navigator.xr.offerSession()`.
     * Wonderland Engine requires to be aware that a session is started, and this
     * is done through this call.
     *
     * @param mode The XR mode.
     * @param features An array of required features, e.g., `['local-floor', 'hit-test']`.
     * @param optionalFeatures An array of optional features, e.g., `['bounded-floor', 'depth-sensing']`.
     * @returns A promise resolving with the `XRSession`, a string error message otherwise.
     *
     * @since 1.1.5
     */
    offerXRSession(mode: XRSessionMode, features: string[], optionalFeatures?: string[]): Promise<XRSession>;
    /**
     * Wrap an object ID using {@link Object}.
     *
     * @note This method performs caching and will return the same
     * instance on subsequent calls.
     *
     * @param objectId ID of the object to create.
     * @returns The object
     *
     * @deprecated Use {@link Scene#wrap} instead.
     *
     */
    wrapObject(objectId: number): Object3D;
    toString(): string;
    /** Currently active scene. */
    get scene(): Scene;
    /**
     * WebAssembly bridge.
     *
     * @note Use with care. This object is used to communicate
     * with the WebAssembly code throughout the api.
     *
     * @hidden
     */
    get wasm(): WASM;
    /**
     * WebXR api.
     *
     * @hidden
     */
    get webxr(): WebXR;
    /** Canvas element that Wonderland Engine renders to. */
    get canvas(): HTMLCanvasElement;
    /**
     * Current WebXR session or `null` if no session active.
     *
     * @deprecated Use {@link XRSessionState.session} on the {@link xr}
     * object instead.
     */
    get xrSession(): XRSession | null;
    /**
     * Current WebXR frame or `null` if no session active.
     *
     * @deprecated Use {@link XRSessionState.frame} on the {@link xr}
     * object instead.
     */
    get xrFrame(): XRFrame | null;
    /**
     * Current WebXR base layer or `null` if no session active.
     *
     * @deprecated Use {@link XRSessionState.baseLayer} on the {@link xr}
     * object instead.
     */
    get xrBaseLayer(): XRProjectionLayer | XRWebGLLayer | null;
    /**
     * Current WebXR framebuffer or `null` if no session active.
     *
     * @deprecated Use {@link XRSessionState.framebuffers} on the {@link xr}
     * object instead.
     */
    get xrFramebuffer(): WebGLFramebuffer | null;
    /**
     * WebXR framebuffer scale factor.
     */
    get xrFramebufferScaleFactor(): number;
    set xrFramebufferScaleFactor(value: number);
    /** Physics manager, only available when physx is enabled in the runtime. */
    get physics(): Physics | null;
    /** Texture resources */
    get textures(): TextureManager;
    /** Material resources */
    get materials(): MaterialManager;
    /** Mesh resources */
    get meshes(): MeshManager;
    /** Morph target set resources */
    get morphTargets(): ResourceManager<MorphTargets>;
    /** Font resources */
    get fonts(): ResourceManager<Font>;
    /** Particle effect resources */
    get particleEffects(): ResourceManager<ParticleEffect>;
    /** Get all uncompressed images. */
    get images(): ImageLike[];
    /**
     * Promise that resolve once all uncompressed images are loaded.
     *
     * This is equivalent to calling {@link WonderlandEngine.images}, and wrapping each
     * `load` listener into a promise.
     */
    get imagesPromise(): Promise<ImageLike[]>;
    /**
     * `true` if the texture streaming is currently idle, i.e.,
     * not attempting to upload any textures.
     *
     * @hidden
     */
    get isTextureStreamingIdle(): boolean;
    /**
     * `true` if reverse-Z rendering is supported and enabled.
     *
     * @hidden
     */
    get isReverseZEnabled(): boolean;
    set autoResizeCanvas(flag: boolean);
    /** `true` if the canvas is automatically resized by the engine. */
    get autoResizeCanvas(): boolean;
    /** Retrieves the runtime version. */
    get runtimeVersion(): Version;
    /** Engine {@link Logger}. Use it to turn on / off logging. */
    get log(): Logger;
    /**
     * Initialize the engine.
     *
     * @note Should be called after the WebAssembly is fully loaded.
     *
     * @hidden
     */
    _init(withRenderer: boolean): boolean;
    /**
     * Reset the runtime state, including:
     *     - Component cache
     *     - Images
     *     - Callbacks
     *
     * @note This api is meant to be used internally.
     *
     * @hidden
     */
    _reset(): Promise<void>;
    /**
     * Attempt to hot reload the engine.
     *
     * @param filename URL of the file to use for the reload.
     *     If `null`, forces a full page reload.
     *
     * @hidden
     */
    _reloadRequest(filename: string | null): Promise<void>;
    /**
     * Add an empty scene.
     *
     * @returns The newly created scene
     *
     * @hidden
     */
    _createEmpty(): Scene;
    /** @hidden */
    _destroyScene(instance: Prefab): void;
    /**
     * Reload the state of the engine with a new main scene.
     *
     * @param index Scene index.
     *
     * @hidden
     */
    private _reload;
    /**
     * Helper to load a main scene from an `ArrayBuffer` or `ReadableStream`.
     *
     * @param data Buffer or stream.
     * @param url Base URL.
     * @param nocache If `true`, force a browser reload of files to download.
     *     Only affects components loading for now.
     * @param options Activation options.
     * @returns The loaded main scene.
     *
     * @hidden
     */
    private _loadMainScene;
    /**
     * Helper to load prefab and activatable scene from an `ArrayBuffer`.
     *
     * @param PrefabClass Scene constructor.
     * @param options Loading options.
     * @returns The loaded prefab.
     *
     * @hidden
     */
    private _loadSceneFromBuffer;
    /**
     * Helper to load prefab and activatable scene from a `ReadableStream`.
     *
     * @param PrefabClass Scene constructor.
     * @param options Loading options.
     * @returns The loaded prefab.
     *
     * @hidden
     */
    private _loadSceneFromStream;
    /**
     * Checks if the loaded scene is a prefab and throws an error if not.
     *
     * @param scene The loaded scene
     *
     * @hidden
     */
    private _validateLoadedPrefab;
    /**
     * Checks if the loaded scene is a scene (and not a prefab) and throws an
     * error if not.
     *
     * @param scene The loaded scene
     *
     * @hidden
     */
    private _validateLoadedScene;
    /**
     * Set the scene data on the engine, before the activation occurs.
     *
     * @hidden
     */
    private _preactivate;
    /**
     * Notify the runtime when images are ready to be uploaded.
     *
     * @param sceneIndex Index of the scene where the image originated
     * @hidden
     */
    private _loadUncompressedImages;
}