/**
* Projects exported for the Web expose the :js:class:`Engine` class to the JavaScript environment, that allows
* fine control over the engine's start-up process.
*
* This API is built in an asynchronous manner and requires basic understanding
* of `Promises <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Using_promises>`__.
*
* @module Engine
* @header Web export JavaScript reference
*/
const Engine = (function () {
const preloader = new Preloader();
let loadPromise = null;
let loadPath = '';
let initPromise = null;
/**
* @classdesc The ``Engine`` class provides methods for loading and starting exported projects on the Web. For default export
* settings, this is already part of the exported HTML page. To understand practical use of the ``Engine`` class,
* see :ref:`Custom HTML page for Web export <doc_customizing_html5_shell>`.
*
* @description Create a new Engine instance with the given configuration.
*
* @global
* @constructor
* @param {EngineConfig} initConfig The initial config for this instance.
*/
function Engine(initConfig) { // eslint-disable-line no-shadow
this.config = new InternalConfig(initConfig);
this.rtenv = null;
}
/**
* Load the engine from the specified base path.
*
* @param {string} basePath Base path of the engine to load.
* @param {number=} [size=0] The file size if known.
* @returns {Promise} A Promise that resolves once the engine is loaded.
*
* @function Engine.load
*/
Engine.load = function (basePath, size) {
if (loadPromise == null) {
loadPath = basePath;
loadPromise = preloader.loadPromise(`${loadPath}.wasm`, size, true);
requestAnimationFrame(preloader.animateProgress);
}
return loadPromise;
};
/**
* Unload the engine to free memory.
*
* This method will be called automatically depending on the configuration. See :js:attr:`unloadAfterInit`.
*
* @function Engine.unload
*/
Engine.unload = function () {
loadPromise = null;
};
/**
* Safe Engine constructor, creates a new prototype for every new instance to avoid prototype pollution.
* @ignore
* @constructor
*/
function SafeEngine(initConfig) {
const proto = /** @lends Engine.prototype */ {
/**
* Initialize the engine instance. Optionally, pass the base path to the engine to load it,
* if it hasn't been loaded yet. See :js:meth:`Engine.load`.
*
* @param {string=} basePath Base path of the engine to load.
* @return {Promise} A ``Promise`` that resolves once the engine is loaded and initialized.
*/
init: function (basePath) {
if (initPromise) {
return initPromise;
}
if (loadPromise == null) {
if (!basePath) {
initPromise = Promise.reject(new Error('A base path must be provided when calling `init` and the engine is not loaded.'));
return initPromise;
}
Engine.load(basePath, this.config.fileSizes[`${basePath}.wasm`]);
}
const me = this;
function doInit(promise) {
// Care! Promise chaining is bogus with old emscripten versions.
// This caused a regression with the Mono build (which uses an older emscripten version).
// Make sure to test that when refactoring.
return new Promise(function (resolve, reject) {
promise.then(function (response) {
const cloned = new Response(response.clone().body, { 'headers': [['content-type', 'application/wasm']] });
Godot(me.config.getModuleConfig(loadPath, cloned)).then(function (module) {
const paths = me.config.persistentPaths;
module['initFS'](paths).then(function (err) {
me.rtenv = module;
if (me.config.unloadAfterInit) {
Engine.unload();
}
resolve();
});
});
});
});
}
preloader.setProgressFunc(this.config.onProgress);
initPromise = doInit(loadPromise);
return initPromise;
},
/**
* Load a file so it is available in the instance's file system once it runs. Must be called **before** starting the
* instance.
*
* If not provided, the ``path`` is derived from the URL of the loaded file.
*
* @param {string|ArrayBuffer} file The file to preload.
*
* If a ``string`` the file will be loaded from that path.
*
* If an ``ArrayBuffer`` or a view on one, the buffer will used as the content of the file.
*
* @param {string=} path Path by which the file will be accessible. Required, if ``file`` is not a string.
*
* @returns {Promise} A Promise that resolves once the file is loaded.
*/
preloadFile: function (file, path) {
return preloader.preload(file, path, this.config.fileSizes[file]);
},
/**
* Start the engine instance using the given override configuration (if any).
* :js:meth:`startGame <Engine.prototype.startGame>` can be used in typical cases instead.
*
* This will initialize the instance if it is not initialized. For manual initialization, see :js:meth:`init <Engine.prototype.init>`.
* The engine must be loaded beforehand.
*
* Fails if a canvas cannot be found on the page, or not specified in the configuration.
*
* @param {EngineConfig} override An optional configuration override.
* @return {Promise} Promise that resolves once the engine started.
*/
start: function (override) {
this.config.update(override);
const me = this;
return me.init().then(function () {
if (!me.rtenv) {
return Promise.reject(new Error('The engine must be initialized before it can be started'));
}
let config = {};
try {
config = me.config.getGodotConfig(function () {
me.rtenv = null;
});
} catch (e) {
return Promise.reject(e);
}
// Godot configuration.
me.rtenv['initConfig'](config);
// Preload GDExtension libraries.
if (me.config.gdextensionLibs.length > 0 && !me.rtenv['loadDynamicLibrary']) {
return Promise.reject(new Error('GDExtension libraries are not supported by this engine version. '
+ 'Enable "Extensions Support" for your export preset and/or build your custom template with "dlink_enabled=yes".'));
}
return new Promise(function (resolve, reject) {
for (const file of preloader.preloadedFiles) {
me.rtenv['copyToFS'](file.path, file.buffer);
}
preloader.preloadedFiles.length = 0; // Clear memory
me.rtenv['callMain'](me.config.args);
initPromise = null;
me.installServiceWorker();
resolve();
});
});
},
/**
* Start the game instance using the given configuration override (if any).
*
* This will initialize the instance if it is not initialized. For manual initialization, see :js:meth:`init <Engine.prototype.init>`.
*
* This will load the engine if it is not loaded, and preload the main pck.
*
* This method expects the initial config (or the override) to have both the :js:attr:`executable` and :js:attr:`mainPack`
* properties set (normally done by the editor during export).
*
* @param {EngineConfig} override An optional configuration override.
* @return {Promise} Promise that resolves once the game started.
*/
startGame: function (override) {
this.config.update(override);
// Add main-pack argument.
const exe = this.config.executable;
const pack = this.config.mainPack || `${exe}.pck`;
this.config.args = ['--main-pack', pack].concat(this.config.args);
// Start and init with execName as loadPath if not inited.
const me = this;
return Promise.all([
this.init(exe),
this.preloadFile(pack, pack),
]).then(function () {
return me.start.apply(me);
});
},
/**
* Create a file at the specified ``path`` with the passed as ``buffer`` in the instance's file system.
*
* @param {string} path The location where the file will be created.
* @param {ArrayBuffer} buffer The content of the file.
*/
copyToFS: function (path, buffer) {
if (this.rtenv == null) {
throw new Error('Engine must be inited before copying files');
}
this.rtenv['copyToFS'](path, buffer);
},
/**
* Request that the current instance quit.
*
* This is akin the user pressing the close button in the window manager, and will
* have no effect if the engine has crashed, or is stuck in a loop.
*
*/
requestQuit: function () {
if (this.rtenv) {
this.rtenv['request_quit']();
}
},
/**
* Install the progressive-web app service worker.
* @returns {Promise} The service worker registration promise.
*/
installServiceWorker: function () {
if (this.config.serviceWorker && 'serviceWorker' in navigator) {
try {
return navigator.serviceWorker.register(this.config.serviceWorker);
} catch (e) {
return Promise.reject(e);
}
}
return Promise.resolve();
},
};
Engine.prototype = proto;
// Closure compiler exported instance methods.
Engine.prototype['init'] = Engine.prototype.init;
Engine.prototype['preloadFile'] = Engine.prototype.preloadFile;
Engine.prototype['start'] = Engine.prototype.start;
Engine.prototype['startGame'] = Engine.prototype.startGame;
Engine.prototype['copyToFS'] = Engine.prototype.copyToFS;
Engine.prototype['requestQuit'] = Engine.prototype.requestQuit;
Engine.prototype['installServiceWorker'] = Engine.prototype.installServiceWorker;
// Also expose static methods as instance methods
Engine.prototype['load'] = Engine.load;
Engine.prototype['unload'] = Engine.unload;
return new Engine(initConfig);
}
// Closure compiler exported static methods.
SafeEngine['load'] = Engine.load;
SafeEngine['unload'] = Engine.unload;
// Feature-detection utilities.
SafeEngine['isWebGLAvailable'] = Features.isWebGLAvailable;
SafeEngine['isFetchAvailable'] = Features.isFetchAvailable;
SafeEngine['isSecureContext'] = Features.isSecureContext;
SafeEngine['isCrossOriginIsolated'] = Features.isCrossOriginIsolated;
SafeEngine['isSharedArrayBufferAvailable'] = Features.isSharedArrayBufferAvailable;
SafeEngine['isAudioWorkletAvailable'] = Features.isAudioWorkletAvailable;
SafeEngine['getMissingFeatures'] = Features.getMissingFeatures;
return SafeEngine;
}());
if (typeof window !== 'undefined') {
window['Engine'] = Engine;
}
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