feat: add basic profiling/metrics system (#104)

- Add ProfilingMetrics struct to track performance data
- Track frame time (current and 60-frame rolling average)
- Calculate FPS from average frame time
- Count draw calls, UI elements, and visible elements per frame
- Track total runtime and current frame number
- PyScene counts elements during render
- Expose metrics via mcrfpy.getMetrics() returning dict

This provides basic performance monitoring capabilities for
identifying bottlenecks and optimizing rendering performance.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/GameEngine.cpp

@@ -140,6 +140,9 @@ void GameEngine::run()
     clock.restart();
     while (running)
     {
+        // Reset per-frame metrics
+        metrics.resetPerFrame();
+        
         currentScene()->update();
         testTimers();
         
@@ -171,8 +174,12 @@ void GameEngine::run()
         currentFrame++;
         frameTime = clock.restart().asSeconds();
         fps = 1 / frameTime;
-        int whole_fps = (int)fps;
-        int tenth_fps = int(fps * 100) % 10;
+        
+        // Update profiling metrics
+        metrics.updateFrameTime(frameTime * 1000.0f); // Convert to milliseconds
+        
+        int whole_fps = metrics.fps;
+        int tenth_fps = (metrics.fps * 10) % 10;
         
         if (!headless && window) {
             window->setTitle(window_title + " " + std::to_string(whole_fps) + "." + std::to_string(tenth_fps) + " FPS");

src/GameEngine.h

@@ -37,6 +37,41 @@ public:
     //std::map<std::string, Timer> timers;
     std::map<std::string, std::shared_ptr<PyTimerCallable>> timers;
     std::string scene;
+    
+    // Profiling metrics
+    struct ProfilingMetrics {
+        float frameTime = 0.0f;          // Current frame time in milliseconds
+        float avgFrameTime = 0.0f;       // Average frame time over last N frames
+        int fps = 0;                     // Frames per second
+        int drawCalls = 0;               // Draw calls per frame
+        int uiElements = 0;              // Number of UI elements rendered
+        int visibleElements = 0;         // Number of visible elements
+        
+        // Frame time history for averaging
+        static constexpr int HISTORY_SIZE = 60;
+        float frameTimeHistory[HISTORY_SIZE] = {0};
+        int historyIndex = 0;
+        
+        void updateFrameTime(float deltaMs) {
+            frameTime = deltaMs;
+            frameTimeHistory[historyIndex] = deltaMs;
+            historyIndex = (historyIndex + 1) % HISTORY_SIZE;
+            
+            // Calculate average
+            float sum = 0.0f;
+            for (int i = 0; i < HISTORY_SIZE; ++i) {
+                sum += frameTimeHistory[i];
+            }
+            avgFrameTime = sum / HISTORY_SIZE;
+            fps = avgFrameTime > 0 ? static_cast<int>(1000.0f / avgFrameTime) : 0;
+        }
+        
+        void resetPerFrame() {
+            drawCalls = 0;
+            uiElements = 0;
+            visibleElements = 0;
+        }
+    } metrics;
     GameEngine();
     GameEngine(const McRogueFaceConfig& cfg);
     ~GameEngine();

src/McRFPy_API.cpp

@@ -45,6 +45,8 @@ static PyMethodDef mcrfpyMethods[] = {
     {"find", McRFPy_API::_find, METH_VARARGS, "find(name, scene=None) - find first UI element with given name"},
     {"findAll", McRFPy_API::_findAll, METH_VARARGS, "findAll(pattern, scene=None) - find all UI elements matching name pattern (supports * wildcards)"},
     
+    {"getMetrics", McRFPy_API::_getMetrics, METH_VARARGS, "getMetrics() - get performance metrics (returns dict)"},
+    
     {NULL, NULL, 0, NULL}
 };
 
@@ -882,3 +884,25 @@ PyObject* McRFPy_API::_findAll(PyObject* self, PyObject* args) {
     
     return results;
 }
+
+PyObject* McRFPy_API::_getMetrics(PyObject* self, PyObject* args) {
+    // Create a dictionary with metrics
+    PyObject* dict = PyDict_New();
+    if (!dict) return NULL;
+    
+    // Add frame time metrics
+    PyDict_SetItemString(dict, "frame_time", PyFloat_FromDouble(game->metrics.frameTime));
+    PyDict_SetItemString(dict, "avg_frame_time", PyFloat_FromDouble(game->metrics.avgFrameTime));
+    PyDict_SetItemString(dict, "fps", PyLong_FromLong(game->metrics.fps));
+    
+    // Add draw call metrics
+    PyDict_SetItemString(dict, "draw_calls", PyLong_FromLong(game->metrics.drawCalls));
+    PyDict_SetItemString(dict, "ui_elements", PyLong_FromLong(game->metrics.uiElements));
+    PyDict_SetItemString(dict, "visible_elements", PyLong_FromLong(game->metrics.visibleElements));
+    
+    // Add general metrics
+    PyDict_SetItemString(dict, "current_frame", PyLong_FromLong(game->getFrame()));
+    PyDict_SetItemString(dict, "runtime", PyFloat_FromDouble(game->runtime.getElapsedTime().asSeconds()));
+    
+    return dict;
+}

src/McRFPy_API.h

@@ -77,4 +77,7 @@ public:
     // Name-based finding methods
     static PyObject* _find(PyObject*, PyObject*);
     static PyObject* _findAll(PyObject*, PyObject*);
+    
+    // Profiling/metrics
+    static PyObject* _getMetrics(PyObject*, PyObject*);
 };

src/PyScene.cpp

@@ -72,8 +72,16 @@ void PyScene::render()
     // Render in sorted order (no need to copy anymore)
     for (auto e: *ui_elements)
     {
-        if (e)
+        if (e) {
+            // Track metrics
+            game->metrics.uiElements++;
+            if (e->visible) {
+                game->metrics.visibleElements++;
+                // Count this as a draw call (each visible element = 1+ draw calls)
+                game->metrics.drawCalls++;
+            }
             e->render();
+        }
     }
     
     // Display is handled by GameEngine