magnum/src/Magnum/Platform/Platform.js.in

/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                2020, 2021, 2022, 2023, 2024, 2025
              Vladimír Vondruš <mosra@centrum.cz>

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
*/

/* JavaScript called by C++ code in EmscriptenApplication and Sdl2Application.
   Doing it this way instead of having it inline with EM_ASM(), because this
   provides an actually usable way of expressing dependencies. With EM_ASM()
   one would instead have to pass
    -s EXPORTED_FUNCTIONS=[...]
   to the linker, and OF COURSE there still isn't a way to combine multiple of
   those together: https://github.com/emscripten-core/emscripten/issues/19058
   Which would mean shifting the burden of specifying all possible exported
   functions to the end user, which has no way to know if the list is correct
   until the actual code needing given function gets called!

   Note: can't use let or const, as that breaks closure compiler:
    ERROR - [JSC_LANGUAGE_FEATURE] This language feature is only supported for
    ECMASCRIPT6 mode or better: const declaration.

   Also, lengthBytesUTF8, stringToUTF8 and UTF8ToString are only made library
   functions as of https://github.com/emscripten-core/emscripten/pull/19097
   (Emscripten 3.1.35), before that they cause an error if included in __deps.
   There's (of course, what else to expect) no way to query Emscripten version
   from within the JS library file, and there's also no useful change in the
   predefined setting variables between 3.1.34 and 35 I could rely on. Well,
   except for STRUCT_INFO, which got removed from settings_internal.js in 35,
   but the dumb-as-a-rock preprocessor in src/parseTools.js doesn't even
   recognize #ifndef, tells me to use #if if I attempt to use #ifdef, and then
   while it does what's expected on 3.1.34, on 3.1.35 it fails on
    ReferenceError: STRUCT_INFO is not defined
   Ourageously stupid. All of this. So what I do instead is passing this file
   through configure_file() and replacing MagnumPlatform_EMSCRIPTEN_3135_ONLY
   with a // on older versions. */

mergeInto(LibraryManager.library, {
    /* Used by both EmscriptenApplication and Sdl2Application */
    magnumPlatformSetContainerCssClass__deps: [
        ${MagnumPlatform_EMSCRIPTEN_3135_ONLY} '$UTF8ToString'
    ],
    magnumPlatformSetContainerCssClass: function(string, size) {
        /* Handle also the classic #container for backwards compatibility. We
           also need to preserve the mn-container otherwise next time we'd have
           no way to look for it anymore.

           Using UTF8ToString() instead of AsciiToString() as it has an
           explicit size parameter and thus doesn't need a null-terminated
           input, which would potentially require yet another allocation.
           UTF8ToString() is also used elsewhere while AsciiToString() isn't,
           so even while AsciiToString() is significantly smaller it would
           still cause the JS to get bigger compared to using UTF8ToString()
           everywhere. */
        (Module['canvas'].closest('.mn-container') ||
         document.getElementById('container')).className = (['mn-container', UTF8ToString(string, size)]).join(' ');
    },
    magnumPlatformSetCursor__deps: [
        ${MagnumPlatform_EMSCRIPTEN_3135_ONLY} '$UTF8ToString'
    ],
    magnumPlatformSetCursor: function(string, size) {
        /* This could again use AsciiToString() but here we can pass explicit
           size and avoid a length calculation */
        Module['canvas'].style.cursor = UTF8ToString(string, size);
    },

    /* Used by EmscriptenApplication only */
    magnumPlatformCanvasId__deps: ['malloc',
        ${MagnumPlatform_EMSCRIPTEN_3135_ONLY} '$lengthBytesUTF8', '$stringToUTF8'
    ],
    magnumPlatformCanvasId: function() {
        var id = '#' + Module['canvas'].id;
        var bytes = lengthBytesUTF8(id) + 1;
        var memory = _malloc(bytes);
        stringToUTF8(id, memory, bytes);
        return memory;
    },
    /* There's also emscripten_set_window_title(), but this takes an explicit
       length, allowing the caller to not need to make a null-terminated copy.
       Sized UTF8ToString() is also used everywhere else in our code, which is
       better than mixing it with unsized according to Emscripten UTF8ToString()
       docs:

        N.B. mixing frequent uses of UTF8ToString() with and without
        maxBytesToRead may throw JS JIT optimizations off, so it is worth to
        consider consistently using one */
    magnumPlatformSetWindowTitle__deps: [
        ${MagnumPlatform_EMSCRIPTEN_3135_ONLY} '$UTF8ToString'
    ],
    magnumPlatformSetWindowTitle: function(string, size) {
        document.title = UTF8ToString(string, size);
    },
    magnumPlatformKeyboardListeningElement__deps: ['malloc',
        ${MagnumPlatform_EMSCRIPTEN_3135_ONLY} '$lengthBytesUTF8', '$stringToUTF8'
    ],
    magnumPlatformKeyboardListeningElement: function() {
        var element = Module['keyboardListeningElement'] || document;

        if(element === document) return 1; /* EMSCRIPTEN_EVENT_TARGET_DOCUMENT */
        if(element === window) return 2; /* EMSCRIPTEN_EVENT_TARGET_WINDOW */
        if('id' in element) {
            var id = '#' + element.id;
            /* This could theoretically also use just stringToAscii(), but
               as stringToUTF8() is used elsewhere stringToAscii() would still
               inflate the JS even though it's smaller. */
            var bytes = lengthBytesUTF8(id) + 1;
            var memory = _malloc(bytes);
            stringToUTF8(id, memory, bytes);
            return memory;
        }

        return 0;
    },
    magnumPlatformRequestAnimationFrame__deps: [
        ${MagnumPlatform_EMSCRIPTEN_2010_ONLY} '$dynCall'
    ],
    magnumPlatformRequestAnimationFrame: function(callback, state) {
        var drawEvent = function() {
            var id = window.requestAnimationFrame(drawEvent);
            if(!dynCall('ii', callback, [state]))
                window.cancelAnimationFrame(id);
        };
        window.requestAnimationFrame(drawEvent);
    },
});

// kate: hl javascript