feat: allow passing assetPathPrefix to ThermionViewerWasm to account for Flutter build asset paths

thermion_dart/lib/thermion_dart/compatibility/web/interop/thermion_viewer_wasm.dart

@@ -35,10 +35,9 @@ extension type _EmscriptenModule(JSObject _) implements JSObject {
 
 typedef ThermionViewerImpl = ThermionViewerWasm;
 
-
 ///
-/// A [ThermionViewer] implementation that forwards calls to
+/// A [ThermionViewer] implementation that forwards calls to the
-/// the (Emscripten-generated) ThermionDart JS module.
+/// (Emscripten-generated) ThermionDart JS module.
 ///
 class ThermionViewerWasm implements ThermionViewer {
   late _EmscriptenModule _module;
@@ -46,8 +45,36 @@ class ThermionViewerWasm implements ThermionViewer {
   bool _initialized = false;
   bool _rendering = false;
 
-  ThermionViewerWasm({JSObject? module, String moduleName = "thermion_dart"}) {
+  ///
-    _module = module as _EmscriptenModule? ?? window.getProperty<_EmscriptenModule>(moduleName.toJS);
+  /// Construct an instance of this class by explicitly passing the
+  /// module instance via the [module] property, or by specifying [moduleName],
+  /// being the name of the window property where the module has already been
+  /// loaded.
+  ///
+  /// Pass [assetPathPrefix] if you need to prepend a path to all asset paths
+  /// (e.g. on Flutter where the asset directory /foo is actually shipped under
+  /// the directory /assets/foo, you would construct this as:
+  ///
+  /// final viewer = ThermionViewerWasm(assetPathPrefix:"/assets/")
+  ///
+  ThermionViewerWasm(
+      {JSObject? module,
+      String moduleName = "thermion_dart",
+      String? assetPathPrefix}) {
+    _module = module as _EmscriptenModule? ??
+        window.getProperty<_EmscriptenModule>(moduleName.toJS);
+    if (assetPathPrefix != null) {
+      _setAssetPathPrefix(assetPathPrefix);
+    }
+  }
+
+  void _setAssetPathPrefix(String assetPathPrefix) {
+    _module.ccall(
+        "thermion_dart_web_set_asset_path_prefix",
+        "void",
+        <JSString>["string".toJS].toJS,
+        <JSAny>[assetPathPrefix.toJS].toJS,
+        null);
   }
 
   JSNumber? _viewer;
@@ -1847,29 +1874,22 @@ class ThermionViewerWasm implements ThermionViewer {
     // TODO: implement zoomUpdate
     throw UnimplementedError();
   }
-  
+
   @override
   Future setShadowType(ShadowType shadowType) async {
-      _module.ccall(
+    _module.ccall("set_shadow_type", "void", ["void*".toJS, "int".toJS].toJS,
-        "set_shadow_type",
+        [_viewer!, shadowType.index.toJS].toJS, null);
-        "void",
-        ["void*".toJS, "int".toJS].toJS,
-        [_viewer!, shadowType.index.toJS].toJS,
-        null);
   }
-  
+
   @override
   Future setShadowsEnabled(bool enabled) async {
-    _module.ccall(
+    _module.ccall("set_shadows_enabled", "void",
-        "set_shadows_enabled",
+        ["void*".toJS, "bool".toJS].toJS, [_viewer!, enabled.toJS].toJS, null);
-        "void",
-        ["void*".toJS, "bool".toJS].toJS,
-        [_viewer!, enabled.toJS].toJS,
-        null);
   }
-  
+
   @override
-  Future setSoftShadowOptions(double penumbraScale, double penumbraRatioScale) async {
+  Future setSoftShadowOptions(
+      double penumbraScale, double penumbraRatioScale) async {
     _module.ccall(
         "set_soft_shadow_options",
         "void",

thermion_dart/native/web/src/cpp/ThermionDartWebApi.cpp

@@ -15,37 +15,6 @@
 #include <emscripten/val.h>
 #include <emscripten/fetch.h>
 
-class PendingCall
-{
-public:
-  PendingCall()
-  {
-  }
-  ~PendingCall() {}
-
-  void Wait()
-  {
-    std::future<int32_t> accumulate_future = prom.get_future();
-    std::cout << "Loaded asset from Flutter of length " << accumulate_future.get() << std::endl;
-  }
-
-  void HandleResponse(void* data, int32_t length)
-  {
-    this->data = data;
-    this->length = length;
-    prom.set_value(length);
-  }
-void* data = nullptr;
-int32_t length = 0;
-
-private:
-  std::mutex mutex_;
-  std::condition_variable cv_;
-  bool notified_ = false;
-  std::promise<int32_t> prom;
-
-};
-
 using emscripten::val;
 
 extern "C"
@@ -60,8 +29,10 @@ extern "C"
   //   return 0;
   // }
 
-  EMSCRIPTEN_KEEPALIVE void thermion_filament_web_load_resource_callback(void* data, int32_t length, void* context) {
+  std::string _assetPathPrefix;
-    ((PendingCall*)context)->HandleResponse(data, length);
+
+  EMSCRIPTEN_KEEPALIVE void thermion_dart_web_set_asset_path_prefix(const char* prefix) {
+    _assetPathPrefix = std::string(prefix);
   }
 
   EMSCRIPTEN_KEEPALIVE EMSCRIPTEN_WEBGL_CONTEXT_HANDLE thermion_dart_web_create_gl_context() {
@@ -160,7 +131,7 @@ extern "C"
     // memcpy(data, request->data, request->numBytes);
     // emscripten_fetch_close(request);
     // return ResourceBuffer { data, (int32_t) request->numBytes, _lastResourceId  } ;
-    auto pathString = std::string(path);
+    auto pathString = _assetPathPrefix + std::string(path);
     void* data = nullptr;
     int32_t numBytes = 0;
 
@@ -199,12 +170,10 @@ extern "C"
       EM_ASM({
           var filename = UTF8ToString($0);
           var data = new Uint8Array(HEAPU8.subarray($1, $1 + $2));
-          console.log('Analyinzg /indexed');
 
           // Ensure the '/indexed' directory exists
           if (!FS.analyzePath('/indexed').exists) {
               FS.mkdir('/indexed');
-              console.log('Made dir /indexed');
           }
                 
           // Create all parent directories
@@ -214,13 +183,10 @@ extern "C"
               currentPath += '/' + parts[i];
               if (!FS.analyzePath(currentPath).exists) {
                   FS.mkdir(currentPath);
-                  console.log("Made dir " + currentPath);
               }
           }
-          console.log('Writing file to /indexed/' + filename);
           // Write the file
           FS.writeFile('/indexed/' + filename, data);
-          console.log('File written, syncing');
           
           FS.syncfs(false, function (err) {
               if (err) {

thermion_flutter/thermion_flutter_web/lib/thermion_flutter_web.dart

@@ -35,7 +35,7 @@ class ThermionFlutterWebPlugin extends ThermionFlutterPlatform {
     var width = window.innerWidth;
     var height = window.innerHeight;
 
-    var viewer = ThermionViewerWasm();
+    var viewer = ThermionViewerWasm(assetPathPrefix: "/assets/");
     await viewer.initialize(width, height, uberArchivePath: uberArchivePath);
     return viewer;
   }