feature!:

This is a breaking change needed to fully implement instancing and stencil highlighting.

Previously, users would work directly with entities (on the Dart side, ThermionEntity), e.g.

final entity = await viewer.loadGlb("some.glb");

However, Filament "entities" are a lower-level abstraction.

Loading a glTF file, for example, inserts multiple entities into the scene.

For example, each mesh, light, and camera within a glTF asset will be assigned an entity. A top-level (non-renderable) entity will also be created for the glTF asset, which can be used to transform the entire hierarchy.

"Asset" is a better representation for loading/inserting objects into the scene; think of this as a bundle of entities.

Unless you need to work directly with transforms, instancing, materials and renderables, you can work directly with ThermionAsset.

examples/flutter/materials/lib/main.dart

@@ -0,0 +1,80 @@
+import 'package:flutter/material.dart';
+import 'package:thermion_flutter/thermion_flutter.dart';
+import 'package:vector_math/vector_math_64.dart' hide Colors;
+
+void main() {
+  runApp(const MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  const MyApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Flutter Demo',
+      theme: ThemeData(
+        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
+        useMaterial3: true,
+      ),
+      home: const MyHomePage(title: 'Flutter Demo Home Page'),
+    );
+  }
+}
+
+class MyHomePage extends StatefulWidget {
+  const MyHomePage({super.key, required this.title});
+
+  final String title;
+
+  @override
+  State<MyHomePage> createState() => _MyHomePageState();
+}
+
+class _MyHomePageState extends State<MyHomePage> {
+  ThermionViewer? _viewer;
+  late ThermionAsset _asset;
+  late MaterialInstance _materialInstance;
+
+  @override
+  void initState() {
+    super.initState();
+    ThermionFlutterPlugin.createViewer().then((viewer) async {
+      _viewer = viewer;
+      await _viewer!.setPostProcessing(true);
+      _materialInstance = await _viewer!.createUnlitMaterialInstance();
+      _asset = await _viewer!.createGeometry(
+          GeometryHelper.cube(normals: false, uvs: false),
+          materialInstances: [_materialInstance]);
+
+      await _viewer!
+          .setTransform(_asset.entity, Matrix4.translation(Vector3.all(2)));
+      await _materialInstance.setParameterFloat4(
+          "baseColorFactor", 0.0, 1.0, 0.0, 1.0);
+      await _viewer!.setCameraPosition(0, 0, 10);
+      await _viewer!.setRendering(true);
+      setState(() {});
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+        body: Stack(children: [
+      if (_viewer == null) CircularProgressIndicator(),
+      if (_viewer != null) ...[
+        Positioned.fill(child: ThermionWidget(viewer: _viewer!)),
+        Align(
+            alignment: Alignment.bottomCenter,
+            child: Padding(
+                padding: EdgeInsets.all(12),
+                child: ElevatedButton(
+                    onPressed: () async {
+                      await _materialInstance.setParameterFloat4(
+                          "baseColorFactor", 1.0, 0.0, 0.0, 1.0);
+                    },
+                    child: Text("Set material property (baseColorFactor)"))))
+      ]
+    ]));
+  }
+}