Finished up MVP for scene callbacks

Nuake/Engine.cpp

@@ -259,12 +259,23 @@ namespace Nuake
 		return std::reinterpret_pointer_cast<EngineSubsystemScriptable>(subsystems[subsystemId]);
 	}
 
-	void Engine::OnWindowSetScene(Ref<Scene> scene)
+	void Engine::OnWindowSetScene(Ref<Scene> oldScene, Ref<Scene> newScene)
 	{
-		if (scene != nullptr)
+		// Inform the subsystems that we are going to destroy/swap out the old scene
+		for (auto subsystem : subsystems)
 		{
-			scene->OnPreInitialize().AddStatic(&Engine::OnScenePreInitialize, scene);
-			scene->OnPostInitialize().AddStatic(&Engine::OnScenePostInitialize, scene);
+			if (subsystem == nullptr)
+				continue;
+
+			subsystem->OnScenePreDestroy(oldScene);
+		}
+
+		// Hook into when the internal pieces of the scene are just about to be ready and when the scene is finally
+		// ready to present (ie, all initialized and loaded).
+		if (newScene != nullptr)
+		{
+			newScene->OnPreInitialize().AddStatic(&Engine::OnScenePreInitialize, newScene);
+			newScene->OnPostInitialize().AddStatic(&Engine::OnScenePostInitialize, newScene);
 		}
 	}
 

Nuake/Engine.h

@@ -58,7 +58,7 @@ namespace Nuake
 		static Ref<EngineSubsystemScriptable> GetScriptedSubsystem(const int subsystemId);
 
 	protected:
-		static void OnWindowSetScene(Ref<Scene> scene);
+		static void OnWindowSetScene(Ref<Scene> oldScene, Ref<Scene> newScene);
 		static void InitializeCoreSubsystems();
 		static void OnScriptingEngineGameAssemblyLoaded();
 

Nuake/src/Subsystems/EngineSubsystem.h

@@ -21,6 +21,7 @@ namespace Nuake
 
         virtual void OnScenePreInitialize(Ref<Scene> scene) {}
         virtual void OnScenePostInitialize(Ref<Scene> scene) {}
+        virtual void OnScenePreDestroy(Ref<Scene> scene) {}
 
     private:
         bool canEverTick = false;

Nuake/src/Subsystems/EngineSubsystemScriptable.cpp

@@ -1,5 +1,7 @@
 #include "EngineSubsystemScriptable.h"
 
+#include "Coral/Type.hpp"
+
 namespace Nuake
 {
  
@@ -32,6 +34,10 @@ void EngineSubsystemScriptable::Tick(float deltaTime)
 
 void EngineSubsystemScriptable::OnScenePreInitialize(Ref<Scene> scene)
 {
+    if (!cSharpObjectInstance.IsValid())
+        return;
+
+    cSharpObjectInstance.InvokeMethod("InternalOnScenePreInitialize");
 }
 
 void EngineSubsystemScriptable::OnScenePostInitialize(Ref<Scene> scene)
@@ -39,9 +45,19 @@ void EngineSubsystemScriptable::OnScenePostInitialize(Ref<Scene> scene)
     if (!cSharpObjectInstance.IsValid())
         return;
 
-    cSharpObjectInstance.InvokeMethod("OnScenePostInitialize", scene);
+    cSharpObjectInstance.InvokeMethod("InternalOnSceneReady");
 }
+
+void EngineSubsystemScriptable::OnScenePreDestroy(Ref<Scene> scene)
+{
+    if (!cSharpObjectInstance.IsValid())
+        return;
+
+    if (cSharpObjectInstance.GetType().GetTypeId() == -1)
+        return;
     
+    cSharpObjectInstance.InvokeMethod("InternalOnScenePreDestroy");
+}
 }
 
 

Nuake/src/Subsystems/EngineSubsystemScriptable.h

@@ -21,6 +21,7 @@ namespace Nuake
 
         virtual void OnScenePreInitialize(Ref<Scene> scene) override;
         virtual void OnScenePostInitialize(Ref<Scene> scene) override;
+        virtual void OnScenePreDestroy(Ref<Scene> scene) override;
 
     private:
         Coral::ManagedObject cSharpObjectInstance;

Nuake/src/Window.cpp

@@ -305,9 +305,9 @@ Ref<Scene> Window::GetScene()
 
 bool Window::SetScene(Ref<Scene> newScene)
 {
+    windowSetSceneDelegate.Broadcast(scene, newScene);
+    
     scene = newScene;
-
-    windowSetSceneDelegate.Broadcast(newScene);
     
     return true;
 }

Nuake/src/Window.h

@@ -14,7 +14,7 @@ namespace Nuake
 	class Scene;
 	class FrameBuffer;
 
-	DECLARE_MULTICAST_DELEGATE(OnWindowSetSceneDelegate, Ref<Scene>)
+	DECLARE_MULTICAST_DELEGATE(OnWindowSetSceneDelegate, Ref<Scene>, Ref<Scene>)
 	
 	class Window
 	{
@@ -66,6 +66,8 @@ namespace Nuake
 		void SetOnWindowClosedCallback(std::function<void(Window& window)> callback);
 		void SetOnDragNDropCallback(std::function<void(Window&, const std::vector<std::string>& paths)> callback);
 
+		// Delegate is broadcasted BEFORE the actual internal scene has been reassigned, this is to keep
+		// the potential old scene relevant before its ultimate destruction.
 		OnWindowSetSceneDelegate& OnWindowSetScene() { return windowSetSceneDelegate; }
 
 	private:

NuakeNet/src/EngineSubsystem.cs

@@ -20,9 +20,29 @@
         }
 
         public virtual void Initialize() {}
-        public virtual void OnScenePreInit(Scene scene) {}
-        public virtual void OnScenePostInit(Scene scene) {}
-        public virtual void OnSceneUnloaded(Scene scene) {}
+        
+        public virtual void OnScenePreInitialize(Scene scene) {}
+        public virtual void OnSceneReady(Scene scene) {}
+        public virtual void OnScenePreDestroy(Scene scene) {}
+        
         public virtual void OnTick(float deltaTime) {}
+        
+        // Since the engine doesn't have the concept of scene instances, we just pass
+        // a new `Scene` here since all functions in Scene are statics. This is largely
+        // to keep the API a little more stable going forward.
+        private void InternalOnScenePreInitialize()
+        {
+            OnScenePreInitialize(new Scene());
+        }
+        
+        private void InternalOnSceneReady()
+        {
+            OnSceneReady(new Scene());
+        }
+
+        private void InternalOnScenePreDestroy()
+        {
+            OnScenePreDestroy(new Scene());
+        }
     }
 }