add grid overlay

thermion_dart/native/include/GridOverlay.hpp

@@ -0,0 +1,53 @@
+#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>
+
+#include "material/gizmo.h"
+
+#include "Aabb2.h"
+
+namespace thermion_filament {
+
+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;
+};
+
+}