implemented functions from NativeFunctions.cs

src/game/GameObjectPool.cpp

@@ -94,17 +94,20 @@ std::pair<u32, GameObject&> GameObjectPool::emplace(GameObject&& new_obj)
     return std::pair<u32, GameObject&>(i, r);
 }
 
-void GameObjectPool::erase(u32 index)
+bool GameObjectPool::erase(u32 index)
 {
     if(index >= size)
         throw UsefulException(ougge_format("index %i is out of size %i", index, size));
-    if(!isIndexUsed(index))
-        throw UsefulException(ougge_format("there is no object at index %i", index));
+    if(!isIndexUsed(index)){
+        // throw UsefulException(ougge_format("there is no object at index %i", index));
+        return false;
+    }
     
     buffer[index] = GameObject();
     used_indices[index/64] &= ~(u64(1)<<(index%64)); // mark index bit as unused
     if(index < first_unused_index)
         first_unused_index = index;
+    return true;
 }
 
 GameObjectPool::iterator::iterator(GameObjectPool* pool, u32 index)

src/game/GameObjectPool.hpp

@@ -45,7 +45,7 @@ public:
     ~GameObjectPool();
     GameObject& get(u32 index);
     std::pair<u32, GameObject&> emplace(GameObject&& new_obj);
-    void erase(u32 index);
+    bool erase(u32 index);
 
     #pragma region iterator class
     class iterator {

src/main.cpp

@@ -40,7 +40,7 @@ public:
 void createExampleObject(Engine& engine){
     std::cout<<"creating ExampleObject"<<std::endl;
     auto& monoSystem = engine.getModule<modules::MonoGameObjectSystem>();
-    game::GameObject& exampleObj = monoSystem.createGameObject();
+    game::GameObject& exampleObj = monoSystem.createAndConstructGameObject();
     std::string componentClassName = "Ougge.ExampleComponent";
     if(!monoSystem.tryCreateComponent(exampleObj, componentClassName))
         throw UsefulException(ougge_format("couldn't create component '%s'", componentClassName.c_str()));

src/modules/MonoGameObjectSystem.cpp

@@ -15,6 +15,28 @@ MonoGameObjectSystem::MonoGameObjectSystem(Engine& engine, u32 max_game_objects)
     gameObjectCtor = Mono::Method<void(u64, u32)>(gameObjectClass, ".ctor");
     gameObjectInvokeUpdate = Mono::Method<void(f64)>(gameObjectClass, "InvokeUpdate");
     gameObjectTryCreateComponent = Mono::Method<Mono::Bool(Mono::String)>(gameObjectClass, "TryCreateComponent_internal");
+    registerNativeCallbacks();
+}
+
+// sets implementations for extern functions from src-csharp/NativeFunctions.cs
+void MonoGameObjectSystem::registerNativeCallbacks(){
+    static MonoGameObjectSystem* this_static = this;
+    if(this_static != this)
+        throw new UsefulException("creation of more than one instance of MonoGameObjectSystem is not allowed");
+
+    auto createGameObject_callback = static_cast<void(*)(u64*, u32*)> (
+        [](u64* id_out, u32* index_out) -> void {
+            this_static->createGameObjectInPool(id_out, index_out);
+        }
+    );
+    mono_add_internal_call("createGameObject", (void*)createGameObject_callback);
+    
+    auto freeGameObject_callback = static_cast<bool(*)(u32)>(
+        [](u32 index) -> bool {
+            return this_static->gameObjectPool.erase(index);
+        }
+    );
+    mono_add_internal_call("freeGameObject", (void*)freeGameObject_callback);
 }
 
 void MonoGameObjectSystem::beginFrame(){
@@ -23,10 +45,20 @@ void MonoGameObjectSystem::beginFrame(){
     }
 }
 
-game::GameObject& MonoGameObjectSystem::createGameObject(){
+// is used in NativeFunctions.cs
+game::GameObject& MonoGameObjectSystem::createGameObjectInPool(u64* id_out, u32* index_out){
     auto pair = gameObjectPool.emplace(game::GameObject(mono.createObject(gameObjectClass)));
+    *id_out = ++obj_id;
+    *index_out = pair.first;
     game::GameObject& obj = pair.second;
-    gameObjectCtor(obj.getObjectHandle().getObject(), ++obj_id, pair.first);
+    return obj;
+}
+
+game::GameObject& MonoGameObjectSystem::createAndConstructGameObject(){
+    u64 obj_id;
+    u32 obj_index;
+    game::GameObject& obj = createGameObjectInPool(&obj_id, &obj_index);
+    gameObjectCtor(obj.getObjectHandle().getObject(), obj_id, obj_index);
     return obj;
 }
 

src/modules/MonoGameObjectSystem.hpp

@@ -24,8 +24,12 @@ public:
     const std::string& getName() override;
     void beginFrame() override;
     
-    game::GameObject& createGameObject();
+    game::GameObject& createAndConstructGameObject();
     bool tryCreateComponent(game::GameObject& obj, const std::string& componentClassName);
+
+private:
+    void registerNativeCallbacks();
+    game::GameObject& createGameObjectInPool(u64* id_out, u32* index_out);
 };
 
 }