OpenRA3/apps/web/openra3.worker.js

'use strict';
// OpenRA3 WebAssembly worker bootstrap.
//
// The whole Emscripten runtime runs here (not on the page main thread), so the
// runtime's filesystem is local to this worker: `FS.createLazyFile` can use
// synchronous XHR to fetch assets on demand without blocking the page.
//
// Protocol with index.html:
//   page -> worker  { canvas, width, height }   (once, transfers the OffscreenCanvas)
//   page -> worker  { type: 'key' | 'text' | 'mousebutton' | 'mousemove' | 'wheel' | 'resize' | 'quit', ... }
//   worker -> page  { log } | { ready } | { openra3Frames }
//
// The Emscripten runtime is started by importScripts('openra3.js') once the
// canvas has arrived; main() then runs here and yields via Asyncify.

// Forward worker warnings/errors (including WebGPU validation messages from the
// runtime) to the page, which logs them to the main console.
(function () {
    var origError = console.error.bind(console);
    var origWarn = console.warn.bind(console);
    console.error = function () {
        origError.apply(null, arguments);
        try { self.postMessage({ log: '[worker error] ' + Array.prototype.join.call(arguments, ' ') }); } catch (e) {}
    };
    console.warn = function () {
        origWarn.apply(null, arguments);
        try { self.postMessage({ log: '[worker warn] ' + Array.prototype.join.call(arguments, ' ') }); } catch (e) {}
    };
})();

self.Module = {
    print: function (text) {
        self.postMessage({ log: String(text) });
    },
    printErr: function (text) {
        self.postMessage({ log: String(text) });
    },
    onRuntimeInitialized: function () {
        self.postMessage({ ready: true });
    },
};

var openra3Started = false;

self.onmessage = function (event) {
    var data = event.data;
    if (!data) return;

    if (!openra3Started) {
        if (!data.canvas) return;
        openra3Started = true;
        var canvas = data.canvas;
        if (data.width && data.height) {
            canvas.width = data.width;
            canvas.height = data.height;
        }
        self.Module.canvas = canvas;

        var start = function () {
            // `?nocache` on the page forces a fresh module + wasm fetch, so a
            // rebuild is picked up without clearing the browser cache.
            var bust = data.bust ? ('?v=' + data.bust) : '';
            if (bust) self.Module.locateFile = function (path) { return path + bust; };
            try {
                importScripts('openra3.js' + bust);
            } catch (error) {
                self.postMessage({ log: 'OpenRA3 worker failed to start: ' + error });
            }
        };

        // The WebGPU backend starts from a device created here (`Module.
        // preinitializedWebGPUDevice`); the WebGL backend ignores it. If WebGPU
        // is unavailable the runtime falls back to WebGL.
        if (typeof navigator !== 'undefined' && navigator.gpu) {
            navigator.gpu.requestAdapter().then(function (adapter) {
                if (!adapter) { start(); return; }
                adapter.requestDevice().then(function (device) {
                    self.Module.preinitializedWebGPUDevice = device;
                    start();
                }).catch(start);
            }).catch(start);
        } else {
            start();
        }
        return;
    }

    // Input is only meaningful once the runtime has initialized its exports.
    switch (data.type) {
    case 'key':
        if (self.Module.ccall) self.Module.ccall('openra3_key', null, ['string', 'number'], [data.code, data.down ? 1 : 0]);
        break;
    case 'text':
        if (self.Module._openra3_text) self.Module._openra3_text(data.char | 0);
        break;
    case 'mousebutton':
        if (self.Module._openra3_mouse_button) self.Module._openra3_mouse_button(data.x, data.y, data.left ? 1 : 0);
        break;
    case 'mousemove':
        if (self.Module._openra3_mouse_move) self.Module._openra3_mouse_move(data.x, data.y, data.dx, data.dy, data.left ? 1 : 0);
        break;
    case 'wheel':
        if (self.Module._openra3_wheel) self.Module._openra3_wheel(data.deltaY);
        break;
    case 'resize':
        if (self.Module._openra3_resize) self.Module._openra3_resize(data.width | 0, data.height | 0);
        break;
    case 'quit':
        if (self.Module._openra3_quit) self.Module._openra3_quit();
        break;
    default:
        break;
    }
};