feature: wasmUrl config

feature: update readme

Author: huanghaiyang

Diff for: README.md

@@ -60,7 +60,8 @@ var options = {
     canvas: document.getElementById('canvas'), // canvas element
     subUrl: '/test/test.ass', // Link to subtitles
     fonts: ['/test/font-1.ttf', '/test/font-2.ttf'], // Links to fonts (not required, default font already included in build)
-    workerUrl: '/libassjs-worker.js' // Link to file "libassjs-worker.js"
+    workerUrl: '/libassjs-worker.js', // Link to file "libassjs-worker.js"
+    wasmUrl: '/libassjs.wasm', // Link to file "libassjs.wasm" (not required, default loaded by workerUrl)
 };
 var instance = new SubtitlesOctopus(options);
 // And then...
@@ -111,6 +112,8 @@ When creating an instance of SubtitleOctopus, you can set the following options:
 - `subContent`: The content of the subtitle file to play. (Require either
   `subContent` or `subUrl` to be specified)
 - `workerUrl`: The URL of the worker. (Default: `libassjs-worker.js`)
+- `wasmUrl`: The URL of the WebAssembly file. (if your wasm file is not in the
+  same directory as the worker, you need to specify this) (Optional)
 - `fonts`: An array of links to the fonts used in the subtitle. (Optional)
 - `availableFonts`: Object with all available fonts - Key is font name in lower
   case, value is link: `{"arial": "/font1.ttf"}` (Optional)

Diff for: src/post-worker.js

@@ -552,7 +552,7 @@ function onMessageFromMainEmscriptenThread(message) {
                 self.renderMode = 'wasm-blend';
                 console.error("'createImageBitmap' needed for 'lossy' unsupported. Falling back to default!");
             }
-
+            self.wasmUrl = message.data.wasmUrl;
             self.availableFonts = message.data.availableFonts;
             self.fallbackFont = message.data.fallbackFont;
             self.lazyFileLoading = message.data.lazyFileLoading;

Diff for: src/pre-worker.js

@@ -77,6 +77,15 @@ Module["preRun"].push(function () {
     }
 });
 
+// override locateFile for wasm file requests
+Module['locateFile'] = function (url) {
+    // if we have a wasmUrl, use it
+    if (self.wasmUrl && /\.wasm$/.test(url)) {
+        return self.wasmUrl;
+    }
+    return url;
+};
+
 Module['onRuntimeInitialized'] = function () {
     self.octObj = new Module.SubtitleOctopus();
 

Diff for: src/subtitles-octopus.js

@@ -32,6 +32,7 @@ var SubtitlesOctopus = function (options) {
     self.onReadyEvent = options.onReady; // Function called when SubtitlesOctopus is ready (optional)
     if (supportsWebAssembly) {
         self.workerUrl = options.workerUrl || 'subtitles-octopus-worker.js'; // Link to WebAssembly worker
+        self.wasmUrl = options.wasmUrl || null; // Link to WebAssembly binary
     } else {
         self.workerUrl = options.legacyWorkerUrl || 'subtitles-octopus-worker-legacy.js'; // Link to legacy worker
     }
@@ -108,6 +109,7 @@ var SubtitlesOctopus = function (options) {
             height: self.canvas.height,
             URL: document.URL,
             currentScript: self.workerUrl,
+            wasmUrl: self.wasmUrl,
             preMain: true,
             renderMode: self.renderMode,
             subUrl: self.subUrl,
@@ -678,7 +680,7 @@ var SubtitlesOctopus = function (options) {
             style: style
         });
     };
-    
+
     self.getStyles = function (onSuccess, onError) {
         self.fetchFromWorker({
             target: 'get-styles'