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.

thermion_dart/native/include/scene/GridOverlay.hpp

@@ -0,0 +1,49 @@
+#pragma once
+
+#include <vector> 
+
+#include <utils/Entity.h>
+#include <filament/Engine.h>
+#include <filament/Material.h>
+#include <filament/MaterialInstance.h>
+#include <filament/Scene.h>
+#include <filament/Camera.h>
+#include <filament/View.h>
+#include <filament/Viewport.h>
+
+#include <gltfio/AssetLoader.h>
+#include <gltfio/FilamentAsset.h>
+#include <gltfio/FilamentInstance.h>
+#include <gltfio/ResourceLoader.h>
+
+#include <filament/IndexBuffer.h>
+#include <filament/InstanceBuffer.h>
+
+namespace thermion {
+
+using namespace filament;
+using namespace utils;
+
+class GridOverlay { 
+    public:
+        GridOverlay(Engine& engine);
+        void destroy();
+
+        utils::Entity sphere() {
+            return _sphereEntity;
+        }
+
+        utils::Entity grid() {
+            return _gridEntity;
+        }
+        
+    private:
+        Engine &_engine;
+        utils::Entity _gridEntity;
+        utils::Entity _sphereEntity;
+        Material* _material;
+        MaterialInstance* _materialInstance;
+        MaterialInstance* _sphereMaterialInstance;
+};
+
+}