update README

README.md

@@ -27,12 +27,13 @@ PRs are welcome but please create a placeholder PR to discuss before writing any
 
 ## Getting Started
 
-This package is currently only tested on Flutter >= `3.15.0-15.2.pre`, so you will need to first switch to the `beta` channel: 
+This package is currently only tested on Flutter >= `3.16.0-0.2.pre`, so you will need to first switch to the `beta` channel: 
 
 ```
 flutter channel beta
 flutter upgrade
 ```
+Earlier versions have specific issues that will prevent them from working on Windows/MacOS!
 
 Next, clone this repository and pull the latest binaries from Git LFS:
 
@@ -115,6 +116,9 @@ When a `FilamentWidget` is added to the widget hierarchy:
 
 It's important to note that there *will* be a delay between adding a `FilamentWidget` and the actual rendering viewport becoming available. This is why we fill `FilamentWidget` with red - to make it abundantly clear that you need to handle this asynchronous delay appropriately.  You can call `await _filamentController.isReadyForScene` if you need to wait until the viewport is actually ready for rendering.
 
+> Currently, the `initial` widget will also be displayed whenever the viewport is resized (including changing orientation on mobile and drag-to-resize on desktop). You probably want to change this from the default red.
+
+
 Congratulations! You now have a scene. It's completely empty, so you probably want to add.
 
 ### Load a background
@@ -358,6 +362,7 @@ Separately, we also force the Filament gltfio library to load assets via in-memo
 ```
 git checkout flutter-filament-windows
 mkdir out && cd out
+"C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe" --build . --target gltf_viewer --config Debug
 ```
 
 Building notes:

example/integration_test/plugin_integration_test.dart

@@ -6,7 +6,6 @@ import 'package:flutter/gestures.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:integration_test/integration_test.dart';
-import 'package:golden_toolkit/golden_toolkit.dart';
 import 'package:polyvox_filament/widgets/filament_widget.dart';
 import '../lib/main.dart' as app;
 
@@ -31,7 +30,7 @@ void main() {
 
   int _counter = 0;
 
-  Future _snapshot(WidgetTester tester, Device device, String label,
+  Future _snapshot(WidgetTester tester, String label,
       [int seconds = 0]) async {
     await tester.pumpAndSettle(Duration(milliseconds: 16));
     for (int i = 0; i < seconds; i++) {
@@ -50,8 +49,6 @@ void main() {
     _counter++;
   }
 
-  late Device device;
-
   Future tap(WidgetTester tester, String label, [int seconds = 0]) async {
     var target = find.text(label).first;
     await tester.dragUntilVisible(
@@ -62,7 +59,7 @@ void main() {
         duration: Duration(milliseconds: 10));
     await tester.tap(target);
     await _snapshot(
-        tester, device, label.replaceAll(RegExp("[ -:]"), ""), seconds);
+        tester, label.replaceAll(RegExp("[ -:]"), ""), seconds);
   }
 
   Future<void> pumpUntilFound(
@@ -84,14 +81,13 @@ void main() {
     timer.cancel();
   }
 
-  testGoldens('test', (WidgetTester tester) async {
+  testWidgets('test', (WidgetTester tester) async {
     app.main();
     await pumpUntilFound(tester, find.byType(app.ExampleWidget));
-    device = Device(size: Size(800, 600), name: "desktop");
 
     await tester.pumpAndSettle();
 
-    await _snapshot(tester, device, "fresh");
+    await _snapshot(tester, "fresh");
 
     await tap(tester, "create viewer (default ubershader)", 4);
 
@@ -111,7 +107,7 @@ void main() {
     await tester.pumpAndSettle();
     await tester.sendEventToBinding(testPointer.scroll(const Offset(0.0, 1.0)));
     await tester.pumpAndSettle();
-    await _snapshot(tester, device, "zoomin");
+    await _snapshot(tester, "zoomin");
 
     // rotate
     testPointer =
@@ -127,7 +123,7 @@ void main() {
     await tester.pumpAndSettle();
     await tester.sendEventToBinding(testPointer.up());
 
-    await _snapshot(tester, device, "rotate", 2);
+    await _snapshot(tester,  "rotate", 2);
 
     // pan
     testPointer = TestPointer(1, PointerDeviceKind.mouse, null, kPrimaryButton);
@@ -144,7 +140,7 @@ void main() {
     await tester.sendEventToBinding(testPointer.up());
     await tester.pumpAndSettle();
 
-    await _snapshot(tester, device, "pan");
+    await _snapshot(tester,  "pan");
 
     await tap(tester, "transform to unit cube");
     await tap(tester, "set shapes position to 1, 1, -1");
@@ -154,9 +150,9 @@ void main() {
     await tap(tester, "move camera to 1, 1, -1");
     await tap(tester, 'set camera to first camera in shapes GLB');
 
-    await tap(tester, 'resize');
-    await tap(tester, 'resize');
-    await tap(tester, 'resize');
-    await tap(tester, 'resize');
+    await tap(tester, 'resize', 1);
+    await tap(tester, 'resize', 1);
+    await tap(tester, 'resize', 1);
+    await tap(tester, 'resize', 1);
   });
 }

example/pubspec.yaml

@@ -6,7 +6,7 @@ description: Demonstrates how to use the polyvox_filament plugin.
 publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 
 environment:
-  sdk: ">=2.12.0 <4.0.0"
+  sdk: ">=3.0.0 <4.0.0"
 
 # Dependencies specify other packages that your package needs in order to work.
 # To automatically upgrade your package dependencies to the latest versions
@@ -29,7 +29,6 @@ dev_dependencies:
   integration_test:
     sdk: flutter
   flutter_lints: ^1.0.0
-  golden_toolkit: ^0.15.0
   crypto:
   image_compare: ^1.1.2
 

lib/filament_controller.dart

@@ -17,11 +17,11 @@ class TextureDetails {
 }
 
 abstract class FilamentController {
-  // the current target size of the viewport, in logical pixels
-  ui.Size size = ui.Size.zero;
 
   Future get isReadyForScene;
 
+  TextureDetails? get textureDetails;
+
   ///
   /// The result(s) of calling [pick] (see below).
   /// This may be a broadcast stream, so you should ensure you have subscribed to this stream before calling [pick].
@@ -29,6 +29,11 @@ abstract class FilamentController {
   ///
   Stream<FilamentEntity?> get pickResult;
 
+  ///
+  /// Whether the controller is currently rendering at [framerate].
+  ///
+  bool get rendering;
+
   ///
   /// Set to true to continuously render the scene at the framerate specified by [setFrameRate] (60 fps by default).
   ///
@@ -63,7 +68,7 @@ abstract class FilamentController {
 
 
   ///
-  /// Destroys the backing texture. You probably want to call [destroy] instead of this; this is exposed mostly for lifecycle changes which are handled by FilamentWidget.
+  /// Destroys the specified backing texture. You probably want to call [destroy] instead of this; this is exposed mostly for lifecycle changes which are handled by FilamentWidget.
   ///
   Future destroyTexture();
 
@@ -79,13 +84,13 @@ abstract class FilamentController {
   /// 5) The FilamentWidget will replace the empty Container with a Texture widget
   /// If you need to wait until a FilamentViewer has been created, [await] the [isReadyForScene] Future.
   ///
-  Future<TextureDetails> createViewer(int width, int height);
+  void createViewer(int width, int height);
 
   ///
   /// Resize the viewport & backing texture.
   /// This is called by FilamentWidget; you shouldn't need to invoke this manually.
   ///
-  Future<TextureDetails> resize(int width, int height, {double scaleFactor = 1.0});
+  Future resize(int width, int height, {double scaleFactor = 1.0});
 
   ///
   /// Set the background image to [path] (which should have a file extension .png, .jpg, or .ktx).

lib/filament_controller_ffi.dart

@@ -16,8 +16,6 @@ class FilamentControllerFFI extends FilamentController {
 
   double _pixelRatio = 1.0;
 
-  int? _textureId;
-
   Completer _isReadyForScene = Completer();
   Future get isReadyForScene => _isReadyForScene.future;
 
@@ -27,13 +25,15 @@ class FilamentControllerFFI extends FilamentController {
 
   Pointer<Void>? _viewer;
 
-  bool _resizing = false;
 
   final String? uberArchivePath;
 
   Stream<FilamentEntity> get pickResult => _pickResultController.stream;
   final _pickResultController = StreamController<FilamentEntity>.broadcast();
 
+  @override
+  TextureDetails? textureDetails;
+
   ///
   /// This controller uses platform channels to bridge Dart with the C/C++ code for the Filament API.
   /// Setting up the context/texture (since this is platform-specific) and the render ticker are platform-specific; all other methods are passed through by the platform channel to the methods specified in PolyvoxFilamentApi.h.
@@ -52,10 +52,11 @@ class FilamentControllerFFI extends FilamentController {
   }
 
   bool _rendering = false;
+  bool get rendering => _rendering;
 
   @override
   Future setRendering(bool render) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _rendering = render;
@@ -64,7 +65,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future render() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.render_ffi(_viewer!);
@@ -89,7 +90,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future destroyViewer() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     var viewer = _viewer;
@@ -103,25 +104,24 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future destroyTexture() async {
-    if (_textureId != null) {
-      throw Exception("No texture available");
+    if(textureDetails != null) {
+      await _channel.invokeMethod("destroyTexture", textureDetails!.textureId);
     }
-    print("Destroying texture");
-    // we need to flush all references to the previous texture ID before calling destroy, otherwise the Texture widget will attempt to render a non-existent texture and crash.
-    // however, this is not a synchronous stream, so we need to ensure the Texture widget has been removed from the hierarchy before destroying
-    _textureId = null;
-    await _channel.invokeMethod("destroyTexture", _textureId!);
     print("Texture destroyed");
   }
 
   ///
   /// Called by `FilamentWidget`. You do not need to call this yourself.
   ///
-  Future<TextureDetails> createViewer(int width, int height) async {
+  void createViewer(int width, int height) async {
     if (_viewer != null) {
       throw Exception(
           "Viewer already exists, make sure you call destroyViewer first");
     }
+    if(textureDetails != null) { 
+      throw Exception(
+          "Texture already exists, make sure you call destroyTexture first");
+    }
     if (_isReadyForScene.isCompleted) {
       throw Exception(
           "Do not call createViewer when a viewer has already been created without calling destroyViewer");
@@ -132,14 +132,14 @@ class FilamentControllerFFI extends FilamentController {
       throw Exception("Failed to get resource loader");
     }
 
-    size = ui.Size(width * _pixelRatio, height * _pixelRatio);
+    var size = ui.Size(width * _pixelRatio, height * _pixelRatio);
 
     print("Creating viewer with size $size");
 
     var textures =
         await _channel.invokeMethod("createTexture", [size.width, size.height]);
     var flutterTextureId = textures[0];
-    _textureId = flutterTextureId;
+
 
     // void* on iOS (pointer to pixel buffer), void* on Android (pointer to native window), null on Windows/macOS
     var surfaceAddress = textures[1] as int? ?? 0;
@@ -193,7 +193,7 @@ class FilamentControllerFFI extends FilamentController {
     _assetManager = _lib.get_asset_manager(_viewer!);
 
     _isReadyForScene.complete(true);
-    return TextureDetails(textureId: _textureId!, width: width, height: height);
+    textureDetails = TextureDetails(textureId: flutterTextureId!, width: width, height: height);
   }
 
   ///
@@ -259,33 +259,38 @@ class FilamentControllerFFI extends FilamentController {
   /// # Given we don't do this on other platforms, I'm OK to stick with the existing solution for the time being.
   /// ############################################################################
   ///
-
-  ///
-  ///
-  /// Other options:
-  /// 1) never destroy the texture, simply allocate a large (4k?) texture and crop as needed
-  /// 2) double-buffering?
+ 
   @override
-  Future<TextureDetails> resize(int width, int height,
-      {double scaleFactor = 1.0}) async {
-    if (_textureId == null) {
-      throw Exception("No texture created, ignoring call to resize.");
-    }
-    var textureId = _textureId;
-    _textureId = null;
+  Future resize(int width, int height, {double scaleFactor = 1.0}) async {
 
+    // we defer to the FilamentWidget to ensure that every call to [resize] is synchronized 
+    // so this exception should never be thrown (right?)
+    if(textureDetails == null) {
+      throw Exception("Resize currently underway, ignoring");
+    }
+
+    var _textureDetails = textureDetails;
+
+    textureDetails = null;
+    
     _lib.set_rendering_ffi(_viewer!, false);
 
-    if (_viewer != null) {
-      _lib.destroy_swap_chain_ffi(_viewer!);
+    if(_textureDetails != null) {
+      if (_viewer != null) {
+        _lib.destroy_swap_chain_ffi(_viewer!);
+      }
+
+      await _channel.invokeMethod("destroyTexture", _textureDetails!.textureId);
+      print("Destroyed texture ${_textureDetails!.textureId}");
     }
 
-    await _channel.invokeMethod("destroyTexture", textureId);
+    var newSize = ui.Size(width * _pixelRatio, height * _pixelRatio);
 
-    size = ui.Size(width * _pixelRatio, height * _pixelRatio);
+    print("Size after pixel ratio : $width x $height ");
 
-    var textures =
-        await _channel.invokeMethod("createTexture", [size.width, size.height]);
+
+    var textures = await _channel
+        .invokeMethod("createTexture", [newSize.width, newSize.height]);
 
     // void* on iOS (pointer to pixel buffer), void* on Android (pointer to native window), null on Windows/macOS
     var surfaceAddress = textures[1] as int? ?? 0;
@@ -296,28 +301,27 @@ class FilamentControllerFFI extends FilamentController {
     _lib.create_swap_chain_ffi(
         _viewer!,
         Pointer<Void>.fromAddress(surfaceAddress),
-        size.width.toInt(),
-        size.height.toInt());
+        newSize.width.toInt(),
+        newSize.height.toInt());
     if (nativeTexture != 0) {
       assert(surfaceAddress == 0);
       print("Creating render target from native texture  $nativeTexture");
       _lib.create_render_target_ffi(
-          _viewer!, nativeTexture, size.width.toInt(), size.height.toInt());
+          _viewer!, nativeTexture, newSize.width.toInt(), newSize.height.toInt());
     }
 
     _lib.update_viewport_and_camera_projection_ffi(
-        _viewer!, size.width.toInt(), size.height.toInt(), 1.0);
+        _viewer!, newSize.width.toInt(), newSize.height.toInt(), 1.0);
 
     await setRendering(_rendering);
-
-    _textureId = textures[0];
-
-    return TextureDetails(textureId: _textureId!, width: width, height: height);
+    textureDetails = TextureDetails(textureId: textures[0]!, width: width, height: height);
   }
 
+  
+
   @override
   Future clearBackgroundImage() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.clear_background_image_ffi(_viewer!);
@@ -325,7 +329,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future setBackgroundImage(String path, {bool fillHeight = false}) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_background_image_ffi(
@@ -334,7 +338,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future setBackgroundColor(Color color) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_background_color_ffi(
@@ -348,7 +352,7 @@ class FilamentControllerFFI extends FilamentController {
   @override
   Future setBackgroundImagePosition(double x, double y,
       {bool clamp = false}) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_background_image_position_ffi(_viewer!, x, y, clamp);
@@ -356,7 +360,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future loadSkybox(String skyboxPath) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.load_skybox_ffi(_viewer!, skyboxPath.toNativeUtf8().cast<Char>());
@@ -364,7 +368,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future loadIbl(String lightingPath, {double intensity = 30000}) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.load_ibl_ffi(
@@ -373,7 +377,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future removeSkybox() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.remove_skybox_ffi(_viewer!);
@@ -381,7 +385,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future removeIbl() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.remove_ibl_ffi(_viewer!);
@@ -399,7 +403,7 @@ class FilamentControllerFFI extends FilamentController {
       double dirY,
       double dirZ,
       bool castShadows) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     var entity = _lib.add_light_ffi(_viewer!, type, colour, intensity, posX,
@@ -409,7 +413,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future removeLight(FilamentEntity light) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.remove_light_ffi(_viewer!, light);
@@ -417,7 +421,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future clearLights() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.clear_lights_ffi(_viewer!);
@@ -425,7 +429,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future<FilamentEntity> loadGlb(String path, {bool unlit = false}) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     if (unlit) {
@@ -446,7 +450,7 @@ class FilamentControllerFFI extends FilamentController {
       throw Exception(
           "loadGltf has a race condition on Windows which is likely to crash your program. If you really want to try, pass force=true to loadGltf");
     }
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     var asset = _lib.load_gltf_ffi(
@@ -461,7 +465,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future panStart(double x, double y) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.grab_begin(_viewer!, x * _pixelRatio, y * _pixelRatio, true);
@@ -469,7 +473,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future panUpdate(double x, double y) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.grab_update(_viewer!, x * _pixelRatio, y * _pixelRatio);
@@ -477,7 +481,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future panEnd() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.grab_end(_viewer!);
@@ -485,7 +489,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future rotateStart(double x, double y) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.grab_begin(_viewer!, x * _pixelRatio, y * _pixelRatio, false);
@@ -493,7 +497,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future rotateUpdate(double x, double y) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.grab_update(_viewer!, x * _pixelRatio, y * _pixelRatio);
@@ -501,7 +505,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future rotateEnd() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.grab_end(_viewer!);
@@ -510,7 +514,7 @@ class FilamentControllerFFI extends FilamentController {
   @override
   Future setMorphTargetWeights(
       FilamentEntity asset, String meshName, List<double> weights) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     var weightsPtr = calloc<Float>(weights.length);
@@ -526,7 +530,7 @@ class FilamentControllerFFI extends FilamentController {
   @override
   Future<List<String>> getMorphTargetNames(
       FilamentEntity asset, String meshName) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     var names = <String>[];
@@ -544,7 +548,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future<List<String>> getAnimationNames(FilamentEntity asset) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     var animationCount = _lib.get_animation_count(_assetManager!, asset);
@@ -561,7 +565,7 @@ class FilamentControllerFFI extends FilamentController {
   @override
   Future<double> getAnimationDuration(
       FilamentEntity asset, int animationIndex) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     var duration =
@@ -573,7 +577,7 @@ class FilamentControllerFFI extends FilamentController {
   @override
   Future setMorphAnimationData(
       FilamentEntity asset, MorphAnimationData animation) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
 
@@ -603,7 +607,7 @@ class FilamentControllerFFI extends FilamentController {
   @override
   Future setBoneAnimation(
       FilamentEntity asset, BoneAnimationData animation) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     // var data = calloc<Float>(animation.frameData.length);
@@ -640,7 +644,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future removeAsset(FilamentEntity asset) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.remove_asset_ffi(_viewer!, asset);
@@ -648,7 +652,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future clearAssets() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.clear_assets_ffi(_viewer!);
@@ -656,7 +660,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future zoomBegin() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.scroll_begin(_viewer!);
@@ -664,7 +668,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future zoomUpdate(double x, double y, double z) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.scroll_update(_viewer!, x, y, z);
@@ -672,7 +676,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future zoomEnd() async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.scroll_end(_viewer!);
@@ -684,7 +688,7 @@ class FilamentControllerFFI extends FilamentController {
       bool reverse = false,
       bool replaceActive = true,
       double crossfade = 0.0}) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.play_animation_ffi(
@@ -693,14 +697,14 @@ class FilamentControllerFFI extends FilamentController {
 
   Future setAnimationFrame(
       FilamentEntity asset, int index, int animationFrame) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_animation_frame(_assetManager!, asset, index, animationFrame);
   }
 
   Future stopAnimation(FilamentEntity asset, int animationIndex) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.stop_animation(_assetManager!, asset, animationIndex);
@@ -708,7 +712,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future setCamera(FilamentEntity asset, String? name) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     var result = _lib.set_camera(
@@ -720,7 +724,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future setToneMapping(ToneMapper mapper) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
 
@@ -729,7 +733,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future setPostProcessing(bool enabled) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
 
@@ -738,35 +742,35 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future setBloom(double bloom) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_bloom_ffi(_viewer!, bloom);
   }
 
   Future setCameraFocalLength(double focalLength) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_camera_focal_length(_viewer!, focalLength);
   }
 
   Future setCameraFocusDistance(double focusDistance) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_camera_focus_distance(_viewer!, focusDistance);
   }
 
   Future setCameraPosition(double x, double y, double z) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_camera_position(_viewer!, x, y, z);
   }
 
   Future moveCameraToAsset(FilamentEntity asset) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.move_camera_to_asset(_viewer!, asset);
@@ -774,7 +778,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future setViewFrustumCulling(bool enabled) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_view_frustum_culling(_viewer!, enabled);
@@ -782,21 +786,21 @@ class FilamentControllerFFI extends FilamentController {
 
   Future setCameraExposure(
       double aperture, double shutterSpeed, double sensitivity) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_camera_exposure(_viewer!, aperture, shutterSpeed, sensitivity);
   }
 
   Future setCameraRotation(double rads, double x, double y, double z) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_camera_rotation(_viewer!, rads, x, y, z);
   }
 
   Future setCameraModelMatrix(List<double> matrix) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     assert(matrix.length == 16);
@@ -810,7 +814,7 @@ class FilamentControllerFFI extends FilamentController {
 
   Future setMaterialColor(FilamentEntity asset, String meshName,
       int materialIndex, Color color) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     var result = _lib.set_material_color(
@@ -828,21 +832,21 @@ class FilamentControllerFFI extends FilamentController {
   }
 
   Future transformToUnitCube(FilamentEntity asset) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.transform_to_unit_cube(_assetManager!, asset);
   }
 
   Future setPosition(FilamentEntity asset, double x, double y, double z) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_position(_assetManager!, asset, x, y, z);
   }
 
   Future setScale(FilamentEntity asset, double scale) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_scale(_assetManager!, asset, scale);
@@ -850,14 +854,14 @@ class FilamentControllerFFI extends FilamentController {
 
   Future setRotation(
       FilamentEntity asset, double rads, double x, double y, double z) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     _lib.set_rotation(_assetManager!, asset, rads, x, y, z);
   }
 
   Future hide(FilamentEntity asset, String meshName) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     if (_lib.hide_mesh(
@@ -866,7 +870,7 @@ class FilamentControllerFFI extends FilamentController {
   }
 
   Future reveal(FilamentEntity asset, String meshName) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     if (_lib.reveal_mesh(
@@ -885,13 +889,13 @@ class FilamentControllerFFI extends FilamentController {
   }
 
   void pick(int x, int y) async {
-    if (_viewer == null || _resizing) {
+    if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
     final outPtr = calloc<EntityId>(1);
     outPtr.value = 0;
 
-    _lib.pick_ffi(_viewer!, x, size.height.toInt() - y, outPtr);
+    _lib.pick_ffi(_viewer!, x, textureDetails!.height - y, outPtr);
     int wait = 0;
     while (outPtr.value == 0) {
       await Future.delayed(Duration(milliseconds: 50));

lib/filament_controller_method_channel.dart

@@ -670,4 +670,12 @@ class FilamentControllerMethodChannel extends FilamentController {
     // TODO: implement getNameForEntity
     throw UnimplementedError();
   }
+  
+  @override
+  // TODO: implement textureDetails
+  TextureDetails? get textureDetails => throw UnimplementedError();
+  
+  @override
+  // TODO: implement rendering
+  bool get rendering => throw UnimplementedError();
 }

lib/widgets/filament_widget.dart

@@ -9,7 +9,7 @@ import 'package:polyvox_filament/filament_controller.dart';
 
 import 'dart:async';
 
-typedef ResizeCallback = void Function(Size oldSize, Size newSize);
+typedef ResizeCallback = void Function(Size newSize);
 
 class ResizeObserver extends SingleChildRenderObjectWidget {
   final ResizeCallback onResized;
@@ -36,14 +36,14 @@ class _RenderResizeObserver extends RenderProxyBox {
     required this.onLayoutChangedCallback,
   }) : super(child);
 
-  late var _oldSize = size;
+  Size _oldSize = Size.zero;
 
   @override
-  void performLayout() {
+  void performLayout() async {
     super.performLayout();
-    if (size != _oldSize) {
-      onLayoutChangedCallback(_oldSize, size);
-      _oldSize = size;
+    if (size.width != _oldSize.width || size.height != _oldSize.height) {
+      onLayoutChangedCallback(size);
+      _oldSize = Size(size.width, size.height);
     }
   }
 }
@@ -65,62 +65,11 @@ class FilamentWidget extends StatefulWidget {
 }
 
 class _FilamentWidgetState extends State<FilamentWidget> {
-  TextureDetails? _textureDetails;
-
-  late final AppLifecycleListener _listener;
-  AppLifecycleState? _lastState;
-
-  String? _error;
-
   int? _width;
   int? _height;
 
-  void _handleStateChange(AppLifecycleState state) async {
-    switch (state) {
-      case AppLifecycleState.detached:
-        print("Detached");
-        _textureDetails = null;
-
-        await widget.controller.destroyViewer();
-        await widget.controller.destroyTexture();
-        break;
-      case AppLifecycleState.hidden:
-        print("Hidden");
-        if (Platform.isIOS) {
-          _textureDetails = null;
-          await widget.controller.destroyViewer();
-          await widget.controller.destroyTexture();
-        }
-        break;
-      case AppLifecycleState.inactive:
-        print("Inactive");
-        break;
-      case AppLifecycleState.paused:
-        print("Paused");
-        break;
-      case AppLifecycleState.resumed:
-        print("Resumed");
-        if (!Platform.isWindows) {
-          if (_textureDetails == null) {
-            var size = ((context.findRenderObject()) as RenderBox).size;
-            print("Size after resuming : $size");
-            _height = size.height.ceil();
-            _width = size.width.ceil();
-            await widget.controller.createViewer(_width!, _height!);
-            print("Created viewer Size after resuming");
-          }
-        }
-        break;
-    }
-    _lastState = state;
-  }
-
   @override
   void initState() {
-    _listener = AppLifecycleListener(
-      onStateChange: _handleStateChange,
-    );
-
     WidgetsBinding.instance.addPostFrameCallback((timeStamp) async {
       // when attaching a debugger via Android Studio on startup, this can delay presentation of the widget
       // (meaning the widget may attempt to create a viewer with size 0x0).
@@ -131,26 +80,174 @@ class _FilamentWidgetState extends State<FilamentWidget> {
       var size = ((context.findRenderObject()) as RenderBox).size;
       _width = size.width.ceil();
       _height = size.height.ceil();
-      try {
-        _textureDetails =
-            await widget.controller.createViewer(_width!, _height!);
-      } catch (err) {
-        setState(() {
-          _error = err.toString();
-        });
+      setState(() {});
+    });
+    super.initState();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    if (_width == null || _height == null) {
+      return widget.initial ?? Container(color: Colors.red);
+    }
+
+    return ResizeObserver(
+        onResized: (newSize) {
+          WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
+            setState(() {
+              _width = newSize.width.ceil();
+              _height = newSize.height.ceil();
+            });
+          });
+        },
+        child: _SizedFilamentWidget(
+          initial: widget.initial,
+          width: _width!,
+          height: _height!,
+          controller: widget.controller,
+        ));
+  }
+}
+
+class _SizedFilamentWidget extends StatefulWidget {
+  final int width;
+  final int height;
+  final Widget? initial;
+  final FilamentController controller;
+
+  const _SizedFilamentWidget(
+      {super.key,
+      required this.width,
+      required this.height,
+      this.initial,
+      required this.controller});
+
+  @override
+  State<StatefulWidget> createState() => _SizedFilamentWidgetState();
+}
+
+class _SizedFilamentWidgetState extends State<_SizedFilamentWidget> {
+  String? _error;
+
+  late final AppLifecycleListener _appLifecycleListener;
+  AppLifecycleState? _lastState;
+
+  @override
+  void initState() {
+    _appLifecycleListener = AppLifecycleListener(
+      onStateChange: _handleStateChange,
+    );
+
+    WidgetsBinding.instance.addPostFrameCallback((timeStamp) async {
+      // when attaching a debugger via Android Studio on startup, this can delay presentation of the widget
+      // (meaning the widget may attempt to create a viewer with size 0x0).
+      // we just add a small delay here which should avoid this
+      if (!kReleaseMode) {
+        await Future.delayed(Duration(seconds: 2));
       }
+      try {
+        widget.controller.createViewer(widget.width, widget.height);
+      } catch (err) {
+        _error = err.toString();
+      }
+      setState(() {});
     });
 
     super.initState();
   }
 
+  Timer? _resizeTimer;
+  bool _resizing = false;
+
+  Future _resize() {
+    final completer = Completer();
+    // resizing the window can be sluggish (particular in debug mode), exacerbated when simultaneously recreating the swapchain and resize the window.
+    // to address this, whenever the widget is resized, we set a timer for Xms in the future.
+    // this timer will call [resize] with the widget size at that point in time.
+    // any subsequent widget resizes will cancel the timer and replace with a new one.
+    // debug mode does need a longer timeout.
+    _resizeTimer?.cancel();
+
+    _resizeTimer = Timer(const Duration(milliseconds: kReleaseMode ? 20 : 100), () async {
+      if(!mounted) {
+        return;
+      }
+      var size = ((context.findRenderObject()) as RenderBox).size;
+      var width = size.width.ceil();
+      var height = size.height.ceil();
+      while (_resizing) {
+        await Future.delayed(Duration(milliseconds: 20));
+      }
+      _resizing = true;
+      await widget.controller.resize(width, height);
+      _resizeTimer = null;
+      setState(() {});
+      _resizing = false;
+      completer.complete();
+    });
+    return completer.future;
+  }
+
+  @override
+  void didUpdateWidget(_SizedFilamentWidget oldWidget) {
+    super.didUpdateWidget(oldWidget);
+
+    if (oldWidget.height != widget.height || oldWidget.width != widget.width) {
+      _resize();
+    }
+  }
+
   @override
   void dispose() {
-    _listener.dispose();
+    _appLifecycleListener.dispose();
     super.dispose();
   }
 
-  Timer? _resizeTimer;
+  bool _wasRenderingOnInactive = false;
+
+  void _handleStateChange(AppLifecycleState state) async {
+    switch (state) {
+      case AppLifecycleState.detached:
+        print("Detached");
+
+        if (widget.controller.textureDetails != null) {
+          await widget.controller.destroyViewer();
+          await widget.controller.destroyTexture();
+        }
+        break;
+      case AppLifecycleState.hidden:
+        print("Hidden");
+        if (Platform.isIOS && widget.controller.textureDetails != null) {
+          await widget.controller.destroyViewer();
+          await widget.controller.destroyTexture();
+        }
+        break;
+      case AppLifecycleState.inactive:
+        print("Inactive");
+        // on Windows in particular, restoring a window after minimizing stalls the renderer (and the whole application) for a considerable length of time.
+        // disabling rendering on minimize seems to fix the issue (so I wonder if there's some kind of command buffer that's filling up while the window is minimized).
+        _wasRenderingOnInactive = widget.controller.rendering;
+        await widget.controller.setRendering(false);
+        break;
+      case AppLifecycleState.paused:
+        print("Paused");
+        break;
+      case AppLifecycleState.resumed:
+        print("Resumed");
+        if (!Platform.isWindows) {
+          if (widget.controller.textureDetails == null) {
+            var size = ((context.findRenderObject()) as RenderBox).size;
+            widget.controller
+                .createViewer(size.width.ceil(), size.height.ceil());
+          }
+        } else {
+          await _resize();
+        }
+        await widget.controller.setRendering(_wasRenderingOnInactive);
+        break;
+    }
+    _lastState = state;
+  }
 
   @override
   Widget build(BuildContext context) {
@@ -164,51 +261,26 @@ class _FilamentWidgetState extends State<FilamentWidget> {
           ]));
     }
 
-    // if no texture ID is available, display the [initial] widget (solid red by default)
-    late Widget content;
-
-    if (_textureDetails == null ||
-        _textureDetails!.height != _height ||
-        _textureDetails!.width != _width) {
-      content = widget.initial ?? Container(color: Colors.red);
-    } else {
-      content = Texture(
-        key: ObjectKey("texture_${_textureDetails!.textureId}"),
-        textureId: _textureDetails!.textureId,
-        filterQuality: FilterQuality.none,
-        freeze: false,
-      );
+    if (widget.controller.textureDetails == null || _resizeTimer != null) {
+      return widget.initial ?? Container(color: Colors.red);
     }
-
     // see [FilamentControllerFFI.resize] for an explanation of how we deal with resizing
-    return ResizeObserver(
-        onResized: (Size oldSize, Size newSize) async {
-          _resizeTimer?.cancel();
+    var texture = Texture(
+      key: ObjectKey("texture_${widget.controller.textureDetails!.textureId}"),
+      textureId: widget.controller.textureDetails!.textureId,
+      filterQuality: FilterQuality.none,
+      freeze: false,
+    );
 
-          _resizeTimer = Timer(const Duration(milliseconds: 50), () async {
-            var newWidth = newSize.width.ceil();
-            var newHeight = newSize.height.ceil();
-            try {
-              _textureDetails =
-                  await widget.controller.resize(newWidth, newHeight);
-              setState(() {
-                _width = newWidth;
-                _height = newHeight;
-              });
-            } catch (err) {
-              print(err);
-            }
-          });
-        },
-        child: Stack(children: [
-          Positioned.fill(
-              child: Platform.isLinux || Platform.isWindows
-                  ? Transform(
-                      alignment: Alignment.center,
-                      transform: Matrix4.rotationX(
-                          pi), // TODO - this rotation is due to OpenGL texture coordinate working in a different space from Flutter, can we move this to the C++ side somewhere?
-                      child: content)
-                  : content)
-        ]));
+    return Stack(children: [
+      Positioned.fill(
+        child: Platform.isLinux || Platform.isWindows
+              ? Transform(
+                  alignment: Alignment.center,
+                  transform: Matrix4.rotationX(
+                      pi), // TODO - this rotation is due to OpenGL texture coordinate working in a different space from Flutter, can we move this to the C++ side somewhere?
+                  child: texture)
+              : texture)
+    ]);
   }
 }

pubspec.yaml

@@ -4,8 +4,8 @@ version: 0.0.1
 homepage:
 
 environment:
-  sdk: ">=3.0.0 <3.11.0"
-  flutter: ">=1.20.0"
+  sdk: ">=3.0.0 <4.0.0"
+  flutter: ">=3.16.0-0.2.pre"
 
 dependencies:
   flutter:

windows/opengl_texture_buffer.cpp

@@ -70,12 +70,14 @@ OpenGLTextureBuffer::OpenGLTextureBuffer(
       std::make_unique<flutter::TextureVariant>(flutter::PixelBufferTexture(
           [=](size_t width,
               size_t height) -> const FlutterDesktopPixelBuffer * {
+
             if (width != this->_width || height != this->_height) {
-              std::cout << "Front-end widget has been resized, you need to "
-                           "teardown/rebuild the swapchain. This pixel buffer "
-                           "will be discarded."
-                        << std::endl;
-              return nullptr;
+              if(!this->logged) {
+                std::cout << "Front-end widget expects " << width << "x" << height << " but this is " << this->_width << "x" << this->_height 
+                          << std::endl;
+                this->logged = true;
+              }
+              return nullptr; 
             }
             uint8_t *data = (uint8_t *)pixelData.get();