HTML5 shell class reference

Projects exported for the Web expose the 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.


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 Custom HTML page for Web export.

Static Methods

Promise Engine.load ( string basePath )
void Engine.unload ( )
boolean Engine.isWebGLAvailable ( [ number majorVersion=1 ] )
void Engine.setWebAssemblyFilenameExtension ( string extension )

Instance Properties

Emscripten Module engine.rtenv

インタンス メソッド

Engine Engine ( )
Promise engine.init ( [ string basePath ] )
Promise engine.preloadFile ( string|ArrayBuffer file [, string path ] )
Promise engine.start ( [ string arg1, string arg2, … ] )
Promise engine.startGame ( string execName, string mainPack )
void engine.setUnloadAfterInit ( boolean enabled )
void engine.setCanvas ( HTMLCanvasElement canvasElem )
void engine.setCanvasResizedOnStart ( boolean enabled )
void engine.setLocale ( string locale )
void engine.setExecutableName ( string execName )
void engine.setProgressFunc ( function callback )
void engine.setStdoutFunc ( function callback )
void engine.setStderrFunc ( function callback )

Static Method Descriptions


Load the engine from the specified base path.

  • basePath (string) -- ロードするエンジンのベースパス。




This method is called automatically once the engine is started unless explicitly disabled using engine.setUnloadAfterInit().

Engine.isWebGLAvailable([majorVersion = 1])

Check whether WebGL is available. Optionally, specify a particular version of WebGL to check for.

  • majorVersion (number) -- The major WebGL version to check for. Defaults to 1 for WebGL 1.0.

指定されたメジャーバージョンのWebGLが利用可能な場合は true、そうでない場合は false


Set an alternative filename extension for the WebAssembly module. By default it is assumed to be wasm.

  • extension (string) -- ドットなしのファイル名拡張子。

Instance Property Descriptions


The runtime environment provided by Emscripten's Module. For more information refer to the official documentation on Emscripten.

Instance Method Descriptions

class Engine()

Create a new instance of the Engine class.


Initialize the engine instance. Optionally, pass the base path to the engine to load it, if it hasn't been loaded yet. See Engine.load().

  • basePath (string) -- ロードするエンジンのベースパス。


engine.preloadFile(file[, path])

Load a file so it is available in the instance's file system once it runs. Must be called before starting the instance.

  • file (string|ArrayBuffer) --

    If type is string, the file will be loaded from that path.

    タイプが ArrayBuffer またはそのビューである場合、バッファはファイルのコンテンツとして使用されます。

  • path (string) -- Path by which the file will be accessible. Required, if file is not a string. If not passed, the path is derived from the URL of the loaded file.

Promise that resolves once the file is loaded.

engine.start([arg1, arg2, ])

Start the instance of the engine, using the passed strings as command line arguments. engine.startGame() can be used in typical cases instead.

This will initialize the instance if it is not initialized. For manual initialization, see engine.init(). The engine must be loaded beforehand.

Fails if a canvas cannot be found on the page.

  • variadic (string) -- Command line argument.


engine.startGame(execName, mainPack)

Start the game instance using the given executable URL and main pack URL.

This will initialize the instance if it is not initialized. For manual initialization, see engine.init().

This will load the engine if it is not loaded. The base path of the executable URL will be used as the engine base path.

  • execName (string) -- Executable name in a form of URL, omitting filename extension.
  • mainPack (string) -- URL of the main pack to start the game.



Specify whether the engine will be unloaded automatically after the instance is initialized. Enabled by default.

  • enabled (boolean) -- エンジンを初期化後にアンロードする場合は true、そうでない場合は false

Specify a canvas HTML element to use. By default, the first canvas element on the page is used for rendering.

  • canvasElem (HTMLCanvasElement) -- The canvas element to use.

Specifies whether the canvas will be resized to the width and height specified in the project settings on start. Enabled by default.

  • enabled (boolean) -- 開始時にcanvasのサイズを変更する場合は true、それ以外の場合は false

Specify a language code to select the proper localization for the game.


Complete list of supported locales.

  • locale (string) -- 言語コード。

Specify the virtual filename of the executable. By default, the base name of the loaded engine files is used.

This affects the output of OS.get_executable_path() and sets the automatically started main pack to ExecutableName.pck.

  • execName (string) -- 実行可能ファイル名。

Specify a callback function for displaying download progress. The callback function is called once per frame, so that the usage of requestAnimationFrame() is not necessary.

If the callback function receives a total amount of bytes as 0, this means that it is impossible to calculate. Possible reasons include:

  • ファイルは、サーバー側のチャンク圧縮で配信されます
  • ファイルはChromium上のサーバー側の圧縮で配信されます
  • すべてのファイルのダウンロードがまだ開始されていません(通常はマルチスレッドを使用しないサーバー)
  • callback (function) -- The callback function must accept two numeric arguments: the amount of bytes loaded so far, and the total number of bytes to load.

Specify a callback function for handling the standard output stream. This method should usually only be used in debug pages. By default, console.log() is used.

  • callback (function) -- The callback function must accept one string argument: the message to print.

Specify a callback function for handling the standard error stream. This method should usually only be used in debug pages. By default, console.warn() is used.

  • callback (function) -- The callback function must accept one string argument: the message to print.