Eksportowanie do sieci Web

HTML5 export allows publishing games made in Godot Engine to the browser. This requires support for WebAssembly and WebGL in the user’s browser.

Ważne

Use the browser-integrated developer console, usually opened with F12, to view debug information like JavaScript, engine, and WebGL errors.

Uwaga

Many browsers, including Firefox and Chromium-based browsers, will not load exported projects when opened locally per file:// protocol. To get around this, use a local server.

Wskazówka

Python offers an easy method to start a local server. Use python -m SimpleHTTPServer with Python 2 or python -m http.server with Python 3 to serve the current working directory at http://localhost:8000.

WebGL 2

Until the OpenGL ES 3 renderer is removed from Godot in favor of Vulkan, HTML5 export uses WebGL 2 when the GLES3 option is selected.

Ostrzeżenie

Usage of WebGL 2 is not recommended due to its expected removal from Godot without replacement.

WebGL 2 is not supported in all browsers. Firefox and Chromium (Chrome, Opera) are the most popular supported browsers, Safari and Edge do not work. On iOS, all browsers are based on WebKit (i.e. Safari), so they will also not work.

Godot’s WebGL 2 renderer has issues with 3D and is no longer maintained.

Ograniczenia

For security and privacy reasons, many features that work effortlessly on native platforms are more complicated on the web platform. Following is a list of limitations you should be aware of when porting a Godot game to the web.

Używanie ciasteczek do przechowywania danych

Users must allow cookies (specifically IndexedDB) if persistence of the user:// file system is desired. When playing a game presented in an iframe, third-party cookies must also be enabled. Incognito/private browsing mode also prevents persistence.

Metoda OS.is_userfs_persistent() może być użyta do sprawdzenia czy system plików user:// jest trwały, ale może dawać fałszywe - pozytywne wyniki w niektórych przypadkach.

Pełny ekran i przechwytywanie myszy

Browsers do not allow arbitrarily entering full screen. The same goes for capturing the cursor. Instead, these actions have to occur as a response to a JavaScript input event. In Godot, this means entering full screen from within a pressed input event callback such as _input or _unhandled_input. Querying the class_Input singleton is not sufficient, the relevant input event must currently be active.

For the same reason, the full screen project setting doesn’t work unless the engine is started from within a valid input event handler. This requires customization of the HTML page.

Audio autoplay

Chrome restricts how websites may play audio. It may be necessary for the player to click or tap or press a key to enable audio.

Zobacz także

Google offers additional information about their Web Audio autoplay policies.

class_HTTPClient and class_HTTPRequest

The HTTP classes have several restrictions on the HTML5 platform:

  • Uzyskanie dostępu lub zmiana StreamPeer nie jest dostępna
  • Threaded/Blocking mode is not available
  • Cannot progress more than once per frame, so polling in a loop will freeze
  • No chunked responses
  • Weryfikacja hosta nie może być wyłączona
  • Subject to same-origin policy

Wyeksportowany .html plik nie może być użyty ponownie

On export, several text placeholders are replaced in the generated HTML file specifically for the given export options. It must not be reused in further exports.

Boot splash is not displayed

The default HTML page does not display the boot splash while loading. However, the image is exported as a PNG file, so custom HTML pages can display it.

Niezaimplementowana funkcjonalność

Poniższe funkcje są obecnie niedostępne na platformie HTML5:

  • Wątki
  • GDNative
  • C#
  • Synchronizacja schowka między Godotem a systemem operacyjnym
  • Networking other than class_HTTPClient and class_WebSocketClient

Wskazówka

Check the list of open HTML5 issues on Github to see if the functionality you’re interested in has an issue yet. If not, open one to communicate your interest.

Obsługa plików

Exporting for the web generates several files to be served from a web server, including a default HTML page for presentation. A custom HTML file can be used, see Customizing the Web export HTML page.

The generated .html file can be used as DirectoryIndex in Apache servers and can be renamed to e.g. index.html at any time, its name is never depended on by default.

The HTML page draws the game at maximum size within the browser window. This way it can be inserted into an <iframe> with the game’s size, as is common on most web game hosting sites.

The other exported files are served as they are, next to the .html file, names unchanged. The .wasm file is a binary WebAssembly module implementing the engine. The .pck file is the Godot main pack containing your game. The .js file contains start-up code and is used by the .html file to access the engine. The .png file contains the boot splash image. It is not used in the default HTML page, but is included for custom HTML pages.

The .pck file is binary, usually delivered with the MIME-type application/octet-stream. The .wasm file is delivered as application/wasm.

Ostrzeżenie

Delivering the WebAssembly module (.wasm) with a MIME-type other than application/wasm can prevent some start-up optimizations.

Delivering the files with server-side compression is recommended especially for the .pck and .wasm files, which are usually large in size. The WebAssembly module compresses particularly well, down to around a quarter of its original size with gzip compression.

Opcje Eksportu

If a runnable web export template is available, a button appears between the Stop scene and Play edited Scene buttons in the editor to quickly open the game in the default browser for testing.

If a path to a Custom HTML shell file is given, it will be used instead of the default HTML page. See Customizing the Web export HTML page.

Head Include is appended into the <head> element of the generated HTML page. This allows to, for example, load webfonts and third-party JavaScript APIs, include CSS, or run JavaScript code.

Wywoływanie JavaScript ze skryptu

In web builds, the JavaScript singleton is implemented. It offers a single method called eval that works similarly to the JavaScript function of the same name. It takes a string as an argument and executes it as JavaScript code. This allows interacting with the browser in ways not possible with script languages integrated into Godot.

func my_func():
    JavaScript.eval("alert('Calling JavaScript per GDScript!');")

The value of the last JavaScript statement is converted to a GDScript value and returned by eval() under certain circumstances:

  • W JavaSkrypt typ number jest w GDScript zwracany jako class_float
  • W JavaSkrypt typ boolean jest w GDScript zwracany jako class_bool
  • W JavaSkrypt typ string jest w GDScript zwracany jako class_string
  • JavaScript ArrayBuffer, TypedArray and DataView are returned as GDScript class_PoolByteArray
func my_func2():
    var js_return = JavaScript.eval("var myNumber = 1; myNumber + 2;")
    print(js_return) # prints '3.0'

Wszystkie inne wartości w JavaScript są zwracane jako null.

HTML5 export templates may be built without support for the singleton. With such templates, and on platforms other than HTML5, calling JavaScript.eval will also return null. The availability of the singleton can be checked with the JavaScript feature tag:

func my_func3():
    if OS.has_feature('JavaScript'):
        JavaScript.eval("""
            console.log('The JavaScript singleton is available')
        """)
    else:
        print("The JavaScript singleton is NOT available")

Wskazówka

GDScript’s multi-line strings, surrounded by 3 quotes """ as in my_func3() above, are useful to keep JavaScript code readable.

The eval method also accepts a second, optional Boolean argument, which specifies whether to execute the code in the global execution context, defaulting to false to prevent polluting the global namespace:

func my_func4():
    # execute in global execution context,
    # thus adding a new JavaScript global variable `MyGlobal`
    JavaScript.eval("var SomeGlobal = {};", true)