FPS/batch counter works

src/features/editScene/EditorApp.cpp

@@ -38,22 +38,31 @@
 //=============================================================================
 
 ImGuiRenderListener::ImGuiRenderListener(Ogre::ImGuiOverlay *imguiOverlay,
-					 EditorUISystem *uiSystem)
+					 EditorUISystem *uiSystem,
+					 Ogre::RenderWindow* renderWindow)
 	: m_imguiOverlay(imguiOverlay)
 	, m_uiSystem(uiSystem)
+	, m_renderWindow(renderWindow)
 {
+	m_lastTime = m_timer.getMilliseconds();
 }
 
 void ImGuiRenderListener::preViewportUpdate(
 	const Ogre::RenderTargetViewportEvent &evt)
 {
 	(void)evt;
+	
+	// Calculate delta time
+	unsigned long currentTime = m_timer.getMilliseconds();
+	m_deltaTime = (currentTime - m_lastTime) / 1000.0f;
+	m_lastTime = currentTime;
+	
 	// Start ImGui frame before viewport renders
 	Ogre::ImGuiOverlay::NewFrame();
 
-	// Render editor UI
+	// Render editor UI with delta time
 	if (m_uiSystem) {
-		m_uiSystem->update();
+		m_uiSystem->update(m_deltaTime);
 	}
 }
 
@@ -61,6 +70,13 @@ void ImGuiRenderListener::postViewportUpdate(
 	const Ogre::RenderTargetViewportEvent &evt)
 {
 	(void)evt;
+	
+	// Capture stats after rendering (they're updated at end of frame)
+	if (m_renderWindow && m_uiSystem) {
+		Ogre::RenderTarget::FrameStats stats = m_renderWindow->getStatistics();
+		m_uiSystem->setLastBatchCount(static_cast<int>(stats.batchCount));
+	}
+	
 	// End ImGui frame after viewport renders
 	ImGui::EndFrame();
 }
@@ -207,7 +223,7 @@ void EditorApp::setup()
 
 		// Create and register ImGui render listener
 		m_imguiListener = std::make_unique<ImGuiRenderListener>(
-			m_imguiOverlay, m_uiSystem.get());
+			m_imguiOverlay, m_uiSystem.get(), getRenderWindow());
 		getRenderWindow()->addListener(m_imguiListener.get());
 
 		// Register input listeners

src/features/editScene/EditorApp.hpp

@@ -31,7 +31,8 @@ class RoomLayoutSystem;
 class ImGuiRenderListener : public Ogre::RenderTargetListener {
 public:
 	ImGuiRenderListener(Ogre::ImGuiOverlay *imguiOverlay,
-			    EditorUISystem *uiSystem);
+			    EditorUISystem *uiSystem,
+			    Ogre::RenderWindow* renderWindow);
 
 	void preViewportUpdate(const Ogre::RenderTargetViewportEvent &evt) override;
 	void postViewportUpdate(const Ogre::RenderTargetViewportEvent &evt) override;
@@ -39,6 +40,15 @@ public:
 private:
 	Ogre::ImGuiOverlay *m_imguiOverlay;
 	EditorUISystem *m_uiSystem;
+	Ogre::RenderWindow* m_renderWindow;
+	
+	// Timer for delta time calculation
+	Ogre::Timer m_timer;
+	unsigned long m_lastTime = 0;
+	float m_deltaTime = 0.0f;
+	
+	// Frame stats (updated in postViewportUpdate)
+	int m_lastBatchCount = 0;
 };
 
 /**

src/features/editScene/systems/EditorUISystem.cpp

@@ -176,7 +176,7 @@ void EditorUISystem::registerModularComponents()
 	ComponentRegistration::registerAll(m_componentRegistry, m_sceneMgr, m_physicsSystem, m_renderWindow);
 }
 
-void EditorUISystem::update()
+void EditorUISystem::update(float deltaTime)
 {
 	// Render UI windows
 	// Note: NewFrame() is called by ImGuiRenderListener::preViewportUpdate
@@ -192,6 +192,9 @@ void EditorUISystem::update()
 	if (m_showFileDialog) {
 		renderFileDialog();
 	}
+	
+	// Render FPS overlay
+	renderFPSOverlay(deltaTime);
 }
 
 void EditorUISystem::setSelectedEntity(flecs::entity entity)
@@ -1131,3 +1134,65 @@ void EditorUISystem::renderFileDialog()
 	
 	ImGui::End();
 }
+
+
+void EditorUISystem::renderFPSOverlay(float deltaTime)
+{
+	// Toggle FPS overlay with F12 key
+	if (ImGui::IsKeyPressed(ImGuiKey_F12)) {
+		m_showFPSOverlay = !m_showFPSOverlay;
+	}
+	
+	if (!m_showFPSOverlay) {
+		return;
+	}
+	
+	// Update FPS calculation
+	m_fpsTimeAccumulator += deltaTime;
+	m_fpsFrameCount++;
+	
+	// Note: Batch count is set by ImGuiRenderListener::postViewportUpdate 
+	// after each frame render (stats are updated at end of frame)
+	
+	// Update FPS every 0.5 seconds for smoother display
+	if (m_fpsTimeAccumulator >= 0.5f) {
+		m_currentFPS = m_fpsFrameCount / m_fpsTimeAccumulator;
+		m_fpsTimeAccumulator = 0.0f;
+		m_fpsFrameCount = 0;
+	}
+	
+	// Set up transparent window style
+	ImGuiWindowFlags windowFlags = ImGuiWindowFlags_NoDecoration | 
+	                               ImGuiWindowFlags_AlwaysAutoResize | 
+	                               ImGuiWindowFlags_NoSavedSettings | 
+	                               ImGuiWindowFlags_NoFocusOnAppearing | 
+	                               ImGuiWindowFlags_NoNav;
+	
+	// Position in top-right corner with padding
+	ImVec2 windowPos = ImVec2(ImGui::GetIO().DisplaySize.x - 10.0f, 10.0f);
+	ImVec2 windowPivot = ImVec2(1.0f, 0.0f); // Top-right pivot
+	
+	ImGui::SetNextWindowPos(windowPos, ImGuiCond_Always, windowPivot);
+	ImGui::SetNextWindowBgAlpha(0.35f); // Semi-transparent background
+	
+	if (ImGui::Begin("FPS Overlay", nullptr, windowFlags)) {
+		// FPS text color based on performance
+		ImVec4 fpsColor;
+		if (m_currentFPS >= 60.0f) {
+			fpsColor = ImVec4(0.0f, 1.0f, 0.0f, 1.0f); // Green for 60+ FPS
+		} else if (m_currentFPS >= 30.0f) {
+			fpsColor = ImVec4(1.0f, 1.0f, 0.0f, 1.0f); // Yellow for 30-60 FPS
+		} else {
+			fpsColor = ImVec4(1.0f, 0.0f, 0.0f, 1.0f); // Red for <30 FPS
+		}
+		
+		ImGui::TextColored(fpsColor, "%.1f FPS", m_currentFPS);
+		ImGui::Text("Batches: %d", m_lastBatchCount);
+		
+		ImGui::Separator();
+		
+		ImVec4 hintColor = ImVec4(1.0f, 1.0f, 1.0f, 0.5f);
+		ImGui::TextColored(hintColor, "F12 to toggle");
+	}
+	ImGui::End();
+}

src/features/editScene/systems/EditorUISystem.hpp

@@ -35,7 +35,12 @@ public:
 	 * Update and render all UI windows
 	 * Call this once per frame
 	 */
-	void update();
+	void update(float deltaTime);
+	
+	/**
+	 * Render FPS and batch count overlay
+	 */
+	void renderFPSOverlay(float deltaTime);
 
 	/**
 	 * Set the currently selected entity
@@ -83,6 +88,11 @@ public:
 	 * Set physics system for debug toggle
 	 */
 	void setPhysicsSystem(EditorPhysicsSystem* physics) { m_physicsSystem = physics; }
+	
+	/**
+	 * Set last frame batch count (called from render listener)
+	 */
+	void setLastBatchCount(int count) { m_lastBatchCount = count; }
 
 
 
@@ -144,6 +154,15 @@ private:
 
 	// Settings
 	bool m_parentSceneNodes = true; // Whether child entities inherit parent's SceneNode
+	
+	// FPS overlay settings
+	bool m_showFPSOverlay = true;   // Show FPS counter by default
+	
+	// FPS tracking
+	float m_fpsTimeAccumulator = 0.0f;
+	int m_fpsFrameCount = 0;
+	float m_currentFPS = 0.0f;
+	int m_lastBatchCount = 0;
 
 	// Physics system reference (for debug toggle)
 	EditorPhysicsSystem* m_physicsSystem = nullptr;