Invalidate the lighting bind memo in the instanced draw path

examples/smoke_render/lib/smoke_scenes.dart

@@ -211,6 +211,57 @@ final List<SmokeScene> kSmokeScenes = <SmokeScene>[
     scene.add(node);
     return (scene: scene, camera: _camera());
   }),
+  // Two instanced meshes plus a plain mesh, all sharing a lit pipeline.
+  // Covers hardware instancing and, because the draws share a pipeline, the
+  // engine-lighting bind bookkeeping between instanced and non-instanced
+  // draws; a lost bind reads as black or missing geometry here.
+  SmokeScene('instanced_lighting', () {
+    final scene = Scene();
+    scene.add(
+      Node()..addComponent(
+        DirectionalLightComponent(
+          DirectionalLight(direction: vm.Vector3(-0.4, -1.0, -0.35)),
+        ),
+      ),
+    );
+    // Non-instanced receiver, drawn from the same pipeline as the instances.
+    scene.add(
+      Node(
+        mesh: Mesh(
+          PlaneGeometry(width: 4.0, depth: 4.0),
+          PhysicallyBasedMaterial()
+            ..baseColorFactor = vm.Vector4(0.78, 0.78, 0.80, 1.0)
+            ..metallicFactor = 0.0
+            ..roughnessFactor = 0.9
+            ..vertexColorWeight = 0.0,
+        ),
+      )..localTransform = vm.Matrix4.translation(vm.Vector3(0, -0.6, 0)),
+    );
+    // Two separate instanced meshes, so the second one draws after a
+    // same-pipeline run has already started.
+    for (var mesh = 0; mesh < 2; mesh++) {
+      final instanced = InstancedMesh(
+        geometry: CuboidGeometry(vm.Vector3(0.5, 0.5, 0.5)),
+        material: PhysicallyBasedMaterial()
+          ..baseColorFactor = mesh == 0
+              ? vm.Vector4(0.85, 0.35, 0.20, 1.0)
+              : vm.Vector4(0.20, 0.55, 0.90, 1.0)
+          ..metallicFactor = 0.1
+          ..roughnessFactor = 0.45
+          ..vertexColorWeight = 0.0,
+      );
+      for (var i = 0; i < 3; i++) {
+        instanced.addInstance(
+          vm.Matrix4.translation(
+                vm.Vector3((i - 1) * 0.85, mesh * 0.75, mesh * 0.6 - 0.3),
+              ) *
+              vm.Matrix4.rotationY(0.5 + i * 0.3),
+        );
+      }
+      scene.add(Node()..addComponent(InstancedMeshComponent(instanced)));
+    }
+    return (scene: scene, camera: _camera());
+  }),
   // A directional light casting a shadow from a floating cuboid onto a
   // ground plane. Exercises the ShadowPass (a depth-only shadow-map pass)
   // and the lit material's shadow sampling, which the other scenes don't.

packages/flutter_scene/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.20.1
+
+* Fixed instanced meshes losing their lighting, shadow, and fog bindings on GLES, which drew them (and any mesh sharing their pipeline) black.
+
 ## 0.20.0
 
 * The `.fscene` document core (document model, stable ids, JSON/binary serialization, prefab composition, diffing) moved to the new pure-Dart `scene` package; `flutter_scene` re-exports it, so existing imports are unchanged.

packages/flutter_scene/lib/src/gpu/web/render_pass.dart

@@ -195,6 +195,12 @@ base class RenderPass {
   /// through the VAO cache when the draw is issued: (view, slot, whether the
   /// stream is instance-rate).
   final List<(BufferView, int, bool)> _pendingVertexBindings = [];
+
+  /// Uniform-block binding points, and texture units mapped to the GL target
+  /// bound there, occupied since the last [clearBindings]. Recorded so the
+  /// clear can release exactly what it handed out.
+  final Set<int> _boundUniformBlocks = {};
+  final Map<int, int> _boundTextureUnits = {};
   PrimitiveType _primitiveType = PrimitiveType.triangle;
   BufferView? _inlineVertexBufferView;
 
@@ -582,6 +588,7 @@ base class RenderPass {
         bufferView.offsetInBytes,
         lengthInBytes,
       );
+      _boundUniformBlocks.add(blockBinding);
       return;
     }
 
@@ -679,6 +686,7 @@ base class RenderPass {
     final target = texture.glTarget;
     gl.activeTexture(web.WebGL2RenderingContext.TEXTURE0 + unit);
     gl.bindTexture(target, texture.glTexture);
+    _boundTextureUnits[unit] = target;
     if (sampler != null) {
       // Sampler parameters are per-texture-object GL state; skip the ones
       // already applied to this texture. Per-draw texParameteri calls are
@@ -767,16 +775,33 @@ base class RenderPass {
   }
 
   void clearBindings() {
-    // Clears per-draw resource bindings (vertex/index buffers, uniforms,
-    // textures) but NOT the bound pipeline - matching flutter_gpu, where the
-    // pipeline persists until the next bindPipeline. flutter_scene's encoder
-    // relies on this: it caches the last pipeline and skips re-binding it
-    // across consecutive draws with the same material, so nulling it here
-    // would leave later draws with no pipeline.
+    // Drops every per-draw resource binding, leaving the bound pipeline in
+    // place (matching flutter_gpu, where the pipeline persists until the next
+    // bindPipeline; the encoder skips rebinding a pipeline it already bound,
+    // so nulling it here would leave later draws without one).
+    //
+    // Releasing the uniform blocks and texture units matters beyond tidiness.
+    // They are GL context state rather than per-draw descriptors, so leaving
+    // them attached lets a draw that should have rebound a slot read the
+    // previous draw's resource and render correctly, which hides bind
+    // lifetime bugs here that break on the native backends.
     final gl = _gpuContext._gl;
     if (_vao != null) {
       gl.bindVertexArray(null);
     }
+    for (final binding in _boundUniformBlocks) {
+      gl.bindBufferBase(
+        web.WebGL2RenderingContext.UNIFORM_BUFFER,
+        binding,
+        null,
+      );
+    }
+    _boundUniformBlocks.clear();
+    for (final entry in _boundTextureUnits.entries) {
+      gl.activeTexture(web.WebGL2RenderingContext.TEXTURE0 + entry.key);
+      gl.bindTexture(entry.value, null);
+    }
+    _boundTextureUnits.clear();
     _inlineVertexBufferView = null;
     _indexBufferView = null;
     _pendingVertexBindings.clear();

packages/flutter_scene/lib/src/scene_encoder.dart

@@ -358,6 +358,15 @@ base class SceneEncoder {
     _boundPipeline = pipeline;
   }
 
+  // Drops the pass's bindings. The engine-lighting memo tracks what is
+  // already bound on the pass, so it has to be forgotten here or the next
+  // draw skips rebinding slots that were just wiped; never call
+  // `clearBindings` directly.
+  void _clearBindings() {
+    _renderPass.clearBindings();
+    EngineLightingUniforms.invalidateBindMemo();
+  }
+
   void _encode(
     gpu.RenderPipeline pipeline,
     Matrix4 worldTransform,
@@ -376,8 +385,7 @@ base class SceneEncoder {
     // FFI, and re-issuing the full set per item dominated main-thread frame
     // time in draw-heavy scenes.
     if (!identical(_boundPipeline, pipeline)) {
-      _renderPass.clearBindings();
-      EngineLightingUniforms.invalidateBindMemo();
+      _clearBindings();
     }
     _bindPipeline(pipeline);
     // The material reads its cross-fade coverage from this transient field as
@@ -438,7 +446,7 @@ base class SceneEncoder {
     bool windingFlipped,
     double fade,
   ) {
-    _renderPass.clearBindings();
+    _clearBindings();
     _bindPipeline(pipeline);
     material.lodFade = fade;
     final materialVertex = material.materialVertexShader(