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Improve the Exporting for the Web section.

Add "Export Type" options (threads, gdnative, regular).
Add warnings about "secure contexts" limitations.
Mentions threads and GDNative requirements.
Mention WebRTC as a networking API.
General refactor.

(cherry picked from commit 6d36e32eb5db260ac39b37fb594298bddea8b379)
Fabio Alessandrelli 4 years ago
parent
commit
b6f33a8e25
1 changed files with 108 additions and 54 deletions
  1. 108 54
      getting_started/workflow/export/exporting_for_web.rst

+ 108 - 54
getting_started/workflow/export/exporting_for_web.rst

@@ -12,27 +12,11 @@ in the user's browser.
                with :kbd:`F12`, to view **debug information** like JavaScript,
                with :kbd:`F12`, to view **debug information** like JavaScript,
                engine, and WebGL errors.
                engine, and WebGL errors.
 
 
-.. attention:: 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.
-
-               .. tip:: Python offers an easy method to start a local server.
-                        Use ``python -m http.server 8000 --bind 127.0.0.1`` with Python 3 to serve the
-                        current working directory at ``http://localhost:8000``.
-                        `Refer to MDN for additional information <https://developer.mozilla.org/en-US/docs/Learn/Common_questions/set_up_a_local_testing_server>`__.
-
-.. attention:: `There are significant bugs when running HTML5 projects on iOS <https://github.com/godotengine/godot/issues/26554>`__
+.. attention:: `There are significant bugs when running HTML5 projects on iOS <https://github.com/godotengine/godot/issues?q=is:issue+is:open+label:platform:html5+ios>`__
                (regardless of the browser). We recommend using
                (regardless of the browser). We recommend using
                :ref:`iOS' native export functionality <doc_exporting_for_ios>`
                :ref:`iOS' native export functionality <doc_exporting_for_ios>`
                instead, as it will also result in better performance.
                instead, as it will also result in better performance.
 
 
-.. note::
-
-    If you use Linux, due to
-    `poor Firefox WebGL performance <https://bugzilla.mozilla.org/show_bug.cgi?id=1010527>`__,
-    it's recommended to play the exported project using a Chromium-based browser
-    instead of Firefox.
-
 WebGL 2
 WebGL 2
 -------
 -------
 
 
@@ -49,6 +33,43 @@ WebKit (i.e. Safari), so they will also not work.
 
 
 Godot's WebGL 2 renderer has issues with 3D and is no longer maintained.
 Godot's WebGL 2 renderer has issues with 3D and is no longer maintained.
 
 
+.. _doc_javascript_export_options:
+
+Export options
+--------------
+
+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.
+
+You can choose the **Export Type** to select which features will be available:
+
+- *Regular*: is the most compatible across browsers, will not support threads, nor GDNative.
+- *Threads*: will require the browser to support `SharedArrayBuffer <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer>`__
+- *GDNative*: enables GDNative support but makes the binary bigger and slower to load.
+
+If you plan to use :ref:`VRAM compression <doc_import_images>` make sure that
+**Vram Texture Compression** is enabled for the targeted platforms (enabling
+both **For Desktop** and **For Mobile** will result in a bigger, but more
+compatible export).
+
+If a path to a **Custom HTML shell** file is given, it will be used instead of
+the default HTML page. See :ref:`doc_customizing_html5_shell`.
+
+**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.
+
+.. important:: Each project must generate their own HTML file. On export,
+               several text placeholders are replaced in the generated HTML
+               file specifically for the given export options. Any direct
+               modifications to that HTML file will be lost in future exports.
+               To customize the generated file, use the **Custom HTML shell**
+               option.
+
+.. warning:: **Export types** other then *Regular* are not yet supported by the
+             C# version.
+
 Limitations
 Limitations
 -----------
 -----------
 
 
@@ -56,6 +77,19 @@ For security and privacy reasons, many features that work effortlessly on
 native platforms are more complicated on the web platform. Following is a list
 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.
 of limitations you should be aware of when porting a Godot game to the web.
 
 
+.. _doc_javascript_secure_contexts:
+
+.. important:: Browser vendors are making more and more functionalities only
+               available in `secure contexts <https://developer.mozilla.org/en-US/docs/Web/Security/Secure_Contexts>`_,
+               this means that such features are only be available if the web
+               page is served via a secure HTTPS connection (localhost is
+               usually exempt from such requirement).
+
+.. tip:: Check the `list of open HTML5 issues on GitHub
+         <https://github.com/godotengine/godot/issues?q=is:open+is:issue+label:platform:html5>`__
+         to see if the functionality you're interested in has an issue yet. If
+         not, open one to communicate your interest.
+
 Using cookies for data persistence
 Using cookies for data persistence
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
@@ -68,6 +102,26 @@ The method ``OS.is_userfs_persistent()`` can be used to check if the
 ``user://`` file system is persistent, but can give false positives in some
 ``user://`` file system is persistent, but can give false positives in some
 cases.
 cases.
 
 
+Threads
+~~~~~~~
+
+As mentioned :ref:`above <doc_javascript_export_options>` multi-threading is
+only available if the appropriate **Export Type** is set and support for it
+across browsers is still limited.
+
+.. warning:: Requires a :ref:`secure context <doc_javascript_secure_contexts>`.
+             Browsers are also starting to require that the web page is served with specific
+             `cross-origin isolation headers <https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Embedder-Policy>`__.
+
+GDNative
+~~~~~~~~
+
+As mentioned :ref:`above <doc_javascript_export_options>` GDNative is only
+available if the appropriate **Export Type** is set.
+
+The export will also copy the required GDNative ``.wasm`` files to the output
+folder (and must be uploaded to your server along with your game).
+
 Full screen and mouse capture
 Full screen and mouse capture
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
@@ -82,8 +136,8 @@ 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
 engine is started from within a valid input event handler. This requires
 :ref:`customization of the HTML page <doc_customizing_html5_shell>`.
 :ref:`customization of the HTML page <doc_customizing_html5_shell>`.
 
 
-Audio autoplay
-~~~~~~~~~~~~~~
+Audio
+~~~~~
 
 
 Chrome restricts how websites may play audio. It may be necessary for the
 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.
 player to click or tap or press a key to enable audio.
@@ -91,10 +145,20 @@ player to click or tap or press a key to enable audio.
 .. seealso:: Google offers additional information about their `Web Audio autoplay
 .. seealso:: Google offers additional information about their `Web Audio autoplay
              policies <https://sites.google.com/a/chromium.org/dev/audio-video/autoplay>`__.
              policies <https://sites.google.com/a/chromium.org/dev/audio-video/autoplay>`__.
 
 
-:ref:`class_HTTPClient` and :ref:`class_HTTPRequest`
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.. warning:: Access to microphone requires a
+             :ref:`secure context <doc_javascript_secure_contexts>`.
 
 
-The HTTP classes have several restrictions on the HTML5 platform:
+Networking
+~~~~~~~~~~
+
+Low level networking is not implemented due to lacking support in browsers.
+
+Currently, only :ref:`HTTP client <doc_http_client_class>`,
+:ref:`HTTP requests <doc_http_request_class>`,
+:ref:`WebSocket (client) <doc_websocket>` and :ref:`WebRTC <doc_webrtc>` are
+supported.
+
+The HTTP classes also have several restrictions on the HTML5 platform:
 
 
  -  Accessing or changing the ``StreamPeer`` is not possible
  -  Accessing or changing the ``StreamPeer`` is not possible
  -  Threaded/Blocking mode is not available
  -  Threaded/Blocking mode is not available
@@ -103,11 +167,26 @@ The HTTP classes have several restrictions on the HTML5 platform:
  -  Host verification cannot be disabled
  -  Host verification cannot be disabled
  -  Subject to `same-origin policy <https://developer.mozilla.org/en-US/docs/Web/Security/Same-origin_policy>`__
  -  Subject to `same-origin policy <https://developer.mozilla.org/en-US/docs/Web/Security/Same-origin_policy>`__
 
 
-Exported ``.html`` file must not be reused
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Clipboard
+~~~~~~~~~
+
+Clipboard synchronization between engine and the operating system requires a
+browser supporting the `Clipboard API <https://developer.mozilla.org/en-US/docs/Web/API/Clipboard_API>`__,
+additionally, due to the API asynchronous nature might not be reliable when
+accessed from GDScript.
 
 
-Each project must generate their own HTML file. On export, several text placeholders are replaced in the **generated HTML
-file** specifically for the given export options. Any direct modifications to the **generated HTML file** will be lost in future exports. To customize the generated file, see :ref:`doc_customizing_html5_shell`.
+.. warning:: Requires a :ref:`secure context <doc_javascript_secure_contexts>`.
+
+Gamepads
+~~~~~~~~
+
+Gamepads will not be detected until one of their button is pressed. Gamepads
+might have the wrong mapping depending on the browser/OS/gamepad combination,
+sadly the `Gamepad API <https://developer.mozilla.org/en-US/docs/Web/API/Gamepad_API/Using_the_Gamepad_API>`__
+does not provide a reliable way to detect the gamepad information necessary
+to remap them based on model/vendor/OS due to privacy considerations.
+
+.. warning:: Requires a :ref:`secure context <doc_javascript_secure_contexts>`.
 
 
 Boot splash is not displayed
 Boot splash is not displayed
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -122,22 +201,6 @@ Shader language limitations
 When exporting a GLES2 project to HTML5, WebGL 1.0 will be used. WebGL 1.0
 When exporting a GLES2 project to HTML5, WebGL 1.0 will be used. WebGL 1.0
 doesn't support dynamic loops, so shaders using those won't work there.
 doesn't support dynamic loops, so shaders using those won't work there.
 
 
-Unimplemented functionality
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The following functionality is currently unavailable on the HTML5 platform:
-
- -  Threads
- -  GDNative
- -  C#
- -  Clipboard synchronization between engine and operating system
- -  Networking other than :ref:`class_HTTPClient` and :ref:`class_WebSocketClient`
-
-.. tip:: Check the `list of open HTML5 issues on GitHub
-         <https://github.com/godotengine/godot/issues?q=is:open+is:issue+label:platform:html5>`__
-         to see if the functionality you're interested in has an issue yet. If
-         not, open one to communicate your interest.
-
 Serving the files
 Serving the files
 -----------------
 -----------------
 
 
@@ -174,19 +237,10 @@ the ``.pck`` and ``.wasm`` files, which are usually large in size.
 The WebAssembly module compresses particularly well, down to around a quarter
 The WebAssembly module compresses particularly well, down to around a quarter
 of its original size with gzip compression.
 of its original size with gzip compression.
 
 
-Export options
---------------
-
-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 :ref:`doc_customizing_html5_shell`.
+**Hosts that provide on-the-fly compression:** GitHub Pages (gzip)
 
 
-**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.
+**Hosts that don't provide on-the-fly compression:** itch.io, GitLab Pages
+(`supports manual gzip precompression <https://webd97.de/post/gitlab-pages-compression/>`__)
 
 
 .. _doc_javascript_eval:
 .. _doc_javascript_eval: