internal: add bounding box to SceneAsset & subclasses

thermion_dart/native/include/scene/GeometrySceneAsset.hpp

@@ -53,7 +53,14 @@ namespace thermion
             return _materialInstanceCount;
         }
 
-        const Box &getBoundingBox() const { return _boundingBox; }
+        const Aabb getBoundingBox() const override
+        {
+            return Aabb {
+
+                .min = _boundingBox.getMin(), // center - halfExtent
+                .max = _boundingBox.getMax()  // center + halfExtent
+            };
+        }
         VertexBuffer *getVertexBuffer() const { return _vertexBuffer; }
         IndexBuffer *getIndexBuffer() const { return _indexBuffer; }
 
@@ -137,7 +144,6 @@ namespace thermion
         utils::Entity _entity;
         RenderableManager::PrimitiveType _primitiveType;
         std::vector<std::unique_ptr<GeometrySceneAsset>> _instances;
-
     };
 
 } // namespace thermion

thermion_dart/native/include/scene/GltfSceneAsset.hpp

@@ -73,6 +73,10 @@ namespace thermion
             return _asset;
         }
 
+        const Aabb getBoundingBox() const override {
+            return _asset->getBoundingBox();
+        }
+
         void addAllEntities(Scene *scene) override
         {
             scene->addEntities(_asset->getEntities(), _asset->getEntityCount());

thermion_dart/native/include/scene/GltfSceneAssetInstance.hpp

@@ -39,6 +39,10 @@ namespace thermion
             return std::nullptr_t();
         };
 
+        const Aabb getBoundingBox() const override {
+            return _instance->getBoundingBox();
+        }
+
         SceneAssetType getType() override
         {
             return SceneAsset::SceneAssetType::Gltf;

thermion_dart/native/include/scene/SceneAsset.hpp

@@ -22,6 +22,9 @@ class SceneAsset {
         virtual ~SceneAsset() {
             
         }
+
+        virtual const Aabb getBoundingBox() const = 0;
+
         virtual SceneAssetType getType() = 0;
         
         virtual utils::Entity getEntity() {