feat: remove bounding box from SceneAsset and create renderable wireframe bounding box in ThermionAsset

thermion_dart/lib/src/viewer/src/ffi/src/ffi_asset.dart

@@ -16,9 +16,10 @@ class FFIAsset extends ThermionAsset {
   final bool isInstance;
 
   late final ThermionEntity entity;
+  final ThermionViewer viewer;
 
-  FFIAsset(
-      this.pointer, this.sceneManager, this.engine, this._unlitMaterialProvider,
+  FFIAsset(this.pointer, this.sceneManager, this.engine,
+      this._unlitMaterialProvider, this.viewer,
       {this.isInstance = false}) {
     entity = SceneAsset_getEntity(pointer);
   }
@@ -41,7 +42,8 @@ class FFIAsset extends ThermionAsset {
     if (instance == nullptr) {
       throw Exception("No instance available at index $index");
     }
-    return FFIAsset(instance, sceneManager, engine, _unlitMaterialProvider);
+    return FFIAsset(
+        instance, sceneManager, engine, _unlitMaterialProvider, viewer);
   }
 
   ///
@@ -71,7 +73,8 @@ class FFIAsset extends ThermionAsset {
     if (created == FILAMENT_ASSET_ERROR) {
       throw Exception("Failed to create instance");
     }
-    return FFIAsset(created, sceneManager, engine, _unlitMaterialProvider);
+    return FFIAsset(
+        created, sceneManager, engine, _unlitMaterialProvider, viewer);
   }
 
   ///
@@ -90,7 +93,7 @@ class FFIAsset extends ThermionAsset {
     var count = await getInstanceCount();
     final result = List<ThermionAsset>.generate(count, (i) {
       return FFIAsset(SceneAsset_getInstance(pointer, i), sceneManager, engine,
-          _unlitMaterialProvider);
+          _unlitMaterialProvider, viewer);
     });
 
     return result;
@@ -184,4 +187,100 @@ class FFIAsset extends ThermionAsset {
       SceneManager_removeFromScene(sceneManager, child);
     }
   }
+
+  ThermionAsset? _boundingBoxAsset;
+
+  Aabb3 getBoundingBox() {
+    final aabb3 = SceneManager_getRenderableBoundingBox(sceneManager, entity);
+    return aabb3;
+  }
+
+  @override
+  Future<void> setBoundingBoxVisibility(bool visible) async {
+    if (_boundingBoxAsset == null) {
+      final boundingBox = await getBoundingBox();
+      final min = [
+        boundingBox.centerX - boundingBox.halfExtentX,
+        boundingBox.centerY - boundingBox.halfExtentY,
+        boundingBox.centerZ - boundingBox.halfExtentZ
+      ];
+      final max = [
+        boundingBox.centerX + boundingBox.halfExtentX,
+        boundingBox.centerY + boundingBox.halfExtentY,
+        boundingBox.centerZ + boundingBox.halfExtentZ
+      ];
+
+      // Create vertices for the bounding box wireframe
+      // 8 vertices for a cube
+      final vertices = Float32List(8 * 3);
+
+      // Bottom vertices
+      vertices[0] = min[0];
+      vertices[1] = min[1];
+      vertices[2] = min[2]; // v0
+      vertices[3] = max[0];
+      vertices[4] = min[1];
+      vertices[5] = min[2]; // v1
+      vertices[6] = max[0];
+      vertices[7] = min[1];
+      vertices[8] = max[2]; // v2
+      vertices[9] = min[0];
+      vertices[10] = min[1];
+      vertices[11] = max[2]; // v3
+
+      // Top vertices
+      vertices[12] = min[0];
+      vertices[13] = max[1];
+      vertices[14] = min[2]; // v4
+      vertices[15] = max[0];
+      vertices[16] = max[1];
+      vertices[17] = min[2]; // v5
+      vertices[18] = max[0];
+      vertices[19] = max[1];
+      vertices[20] = max[2]; // v6
+      vertices[21] = min[0];
+      vertices[22] = max[1];
+      vertices[23] = max[2]; // v7
+
+      // Indices for lines (24 indices for 12 lines)
+      final indices = [
+        // Bottom face
+        0, 1, 1, 2, 2, 3, 3, 0,
+        // Top face
+        4, 5, 5, 6, 6, 7, 7, 4,
+        // Vertical edges
+        0, 4, 1, 5, 2, 6, 3, 7
+      ];
+
+      // Create unlit material instance for the wireframe
+      final materialInstancePtr =
+          await withPointerCallback<TMaterialInstance>((cb) {
+        final key = Struct.create<TMaterialKey>();
+        MaterialProvider_createMaterialInstanceRenderThread(
+            _unlitMaterialProvider, key.address, cb);
+      });
+
+      final material = FFIMaterialInstance(materialInstancePtr, sceneManager);
+      await material.setParameterFloat4(
+          "baseColorFactor", 1.0, 1.0, 0.0, 1.0); // Yellow wireframe
+
+      // Create geometry for the bounding box
+      final geometry = Geometry(
+        vertices,
+        indices,
+        primitiveType: PrimitiveType.LINES,
+      );
+
+      _boundingBoxAsset = await viewer.createGeometry(
+        geometry,
+        materialInstances: [material],
+        keepData: false,
+      );
+    }
+    if (visible) {
+      await _boundingBoxAsset!.addToScene();
+    } else { 
+      await _boundingBoxAsset!.removeFromScene();
+    }
+  }
 }

thermion_dart/lib/src/viewer/src/ffi/src/ffi_gizmo.dart

@@ -32,6 +32,7 @@ class FFIGizmo extends FFIAsset implements GizmoAsset {
       super.sceneManager,
       super.renderableManager,
       super.unlitMaterialProvider,
+      super.viewer,
       this.gizmoEntities) {
     _nativeCallback =
         NativeCallable<GizmoPickCallbackFunction>.listener(_onPickResult);

thermion_dart/lib/src/viewer/src/ffi/src/thermion_dart.g.dart

@@ -230,6 +230,22 @@ external void MaterialInstance_setStencilWriteMask(
   int mask,
 );
 
+@ffi.Native<ffi.Void Function(ffi.Pointer<TMaterialInstance>, ffi.UnsignedInt)>(
+    symbol: "MaterialInstance_setTransparencyMode", isLeaf: true)
+external void _MaterialInstance_setTransparencyMode(
+  ffi.Pointer<TMaterialInstance> materialInstance,
+  int transparencyMode,
+);
+
+void MaterialInstance_setTransparencyMode(
+  ffi.Pointer<TMaterialInstance> materialInstance,
+  TTransparencyMode transparencyMode,
+) =>
+    _MaterialInstance_setTransparencyMode(
+      materialInstance,
+      transparencyMode.value,
+    );
+
 @ffi.Native<
     ffi.Pointer<TViewer> Function(ffi.Pointer<ffi.Void>, ffi.Pointer<ffi.Void>,
         ffi.Pointer<ffi.Void>, ffi.Pointer<ffi.Char>)>(isLeaf: true)
@@ -741,6 +757,12 @@ external void View_setFrustumCullingEnabled(
   bool enabled,
 );
 
+@ffi.Native<ffi.Pointer<TRenderTarget> Function(ffi.Pointer<TView>)>(
+    isLeaf: true)
+external ffi.Pointer<TRenderTarget> View_getRenderTarget(
+  ffi.Pointer<TView> tView,
+);
+
 @ffi.Native<ffi.Void Function(ffi.Pointer<TView>, ffi.Bool)>(isLeaf: true)
 external void View_setPostProcessing(
   ffi.Pointer<TView> tView,
@@ -1310,6 +1332,15 @@ external void Viewer_createRenderTargetRenderThread(
       onComplete,
 );
 
+@ffi.Native<
+    ffi.Void Function(ffi.Pointer<TViewer>, ffi.Pointer<TRenderTarget>,
+        ffi.Pointer<ffi.NativeFunction<ffi.Void Function()>>)>(isLeaf: true)
+external void Viewer_destroyRenderTargetRenderThread(
+  ffi.Pointer<TViewer> viewer,
+  ffi.Pointer<TRenderTarget> tRenderTarget,
+  ffi.Pointer<ffi.NativeFunction<ffi.Void Function()>> onComplete,
+);
+
 @ffi.Native<
         ffi.Void Function(
             ffi.Pointer<TEngine>,
@@ -2730,6 +2761,30 @@ enum TCullingMode {
       };
 }
 
+enum TTransparencyMode {
+  /// ! the transparent object is drawn honoring the raster state
+  DEFAULT(0),
+
+  /// the transparent object is first drawn in the depth buffer,
+  /// then in the color buffer, honoring the culling mode, but ignoring the depth test function
+  TWO_PASSES_ONE_SIDE(1),
+
+  /// the transparent object is drawn twice in the color buffer,
+  /// first with back faces only, then with front faces; the culling
+  /// mode is ignored. Can be combined with two-sided lighting
+  TWO_PASSES_TWO_SIDES(2);
+
+  final int value;
+  const TTransparencyMode(this.value);
+
+  static TTransparencyMode fromValue(int value) => switch (value) {
+        0 => DEFAULT,
+        1 => TWO_PASSES_ONE_SIDE,
+        2 => TWO_PASSES_TWO_SIDES,
+        _ => throw ArgumentError("Unknown value for TTransparencyMode: $value"),
+      };
+}
+
 typedef EntityId = ffi.Int32;
 typedef DartEntityId = int;
 

thermion_dart/lib/src/viewer/src/ffi/src/thermion_viewer_ffi.dart

@@ -511,7 +511,7 @@ class ThermionViewerFFI extends ThermionViewer {
     }
 
     var thermionAsset =
-        FFIAsset(asset, _sceneManager!, _engine!, _unlitMaterialProvider!);
+        FFIAsset(asset, _sceneManager!, _engine!, _unlitMaterialProvider!, this);
 
     return thermionAsset;
   }
@@ -551,7 +551,7 @@ class ThermionViewerFFI extends ThermionViewer {
       throw Exception("An error occurred loading GLB from buffer");
     }
     return FFIAsset(
-        assetPtr, _sceneManager!, _engine!, _unlitMaterialProvider!);
+        assetPtr, _sceneManager!, _engine!, _unlitMaterialProvider!, this);
   }
 
   ///
@@ -573,7 +573,7 @@ class ThermionViewerFFI extends ThermionViewer {
     }
 
     return FFIAsset(
-        assetPtr, _sceneManager!, _engine!, _unlitMaterialProvider!);
+        assetPtr, _sceneManager!, _engine!, _unlitMaterialProvider!, this);
   }
 
   ///
@@ -1642,7 +1642,7 @@ class ThermionViewerFFI extends ThermionViewer {
     }
 
     var asset =
-        FFIAsset(assetPtr, _sceneManager!, _engine!, _unlitMaterialProvider!);
+        FFIAsset(assetPtr, _sceneManager!, _engine!, _unlitMaterialProvider!, this);
 
     return asset;
   }
@@ -1760,7 +1760,7 @@ class ThermionViewerFFI extends ThermionViewer {
               _sceneManager!, material.pointer, cb);
         }
       });
-      _grid = FFIAsset(ptr, _sceneManager!, _engine!, _unlitMaterialProvider!);
+      _grid = FFIAsset(ptr, _sceneManager!, _engine!, _unlitMaterialProvider!, this);
     }
     await _grid!.addToScene();
     await setLayerVisibility(VisibilityLayers.OVERLAY, true);
@@ -2093,6 +2093,7 @@ class ThermionViewerFFI extends ThermionViewer {
         _sceneManager!,
         _engine!,
         nullptr,
+        this,
         gizmoEntities.toSet()
           ..add(SceneAsset_getEntity(gizmo.cast<TSceneAsset>())));
   }

thermion_dart/lib/src/viewer/src/shared_types/entities.dart

@@ -12,9 +12,8 @@ export 'light_options.dart';
 typedef ThermionEntity = int;
 
 abstract class ThermionAsset {
-  
   ThermionEntity get entity;
-  
+
   Future<List<ThermionEntity>> getChildEntities();
 
   ///
@@ -28,6 +27,11 @@ abstract class ThermionAsset {
   ///
   Future removeStencilHighlight();
 
+  ///
+  /// When visible is [true], renders the bounding box.
+  ///
+  Future setBoundingBoxVisibility(bool visible);
+
   ///
   ///
   ///