backend-infra-engineer: Release v0.3.2 snapshot

src/app/platform/timing.h

@@ -0,0 +1,117 @@
+#ifndef YAZE_APP_CORE_TIMING_H
+#define YAZE_APP_CORE_TIMING_H
+
+#include <SDL.h>
+#include <cstdint>
+
+namespace yaze {
+
+/**
+ * @class TimingManager
+ * @brief Provides accurate timing for animations and frame pacing
+ * 
+ * This class solves the issue where ImGui::GetIO().DeltaTime only updates
+ * when events are processed (mouse movement, etc). It uses SDL's performance
+ * counter to provide accurate timing regardless of input events.
+ */
+class TimingManager {
+ public:
+  static TimingManager& Get() {
+    static TimingManager instance;
+    return instance;
+  }
+
+  /**
+   * @brief Update the timing manager (call once per frame)
+   * @return The delta time since last update in seconds
+   */
+  float Update() {
+    uint64_t current_time = SDL_GetPerformanceCounter();
+    float delta_time = 0.0f;
+    
+    if (last_time_ > 0) {
+      delta_time = (current_time - last_time_) / static_cast<float>(frequency_);
+      
+      // Clamp delta time to prevent huge jumps (e.g., when debugging)
+      if (delta_time > 0.1f) {
+        delta_time = 0.1f;
+      }
+      
+      accumulated_time_ += delta_time;
+      frame_count_++;
+      
+      // Update FPS counter once per second
+      if (accumulated_time_ >= 1.0f) {
+        fps_ = static_cast<float>(frame_count_) / accumulated_time_;
+        frame_count_ = 0;
+        accumulated_time_ = 0.0f;
+      }
+    }
+    
+    last_time_ = current_time;
+    last_delta_time_ = delta_time;
+    return delta_time;
+  }
+  
+  /**
+   * @brief Get the last frame's delta time in seconds
+   */
+  float GetDeltaTime() const {
+    return last_delta_time_;
+  }
+  
+  /**
+   * @brief Get current FPS
+   */
+  float GetFPS() const {
+    return fps_;
+  }
+  
+  /**
+   * @brief Get total elapsed time since first update
+   */
+  float GetElapsedTime() const {
+    if (last_time_ == 0) return 0.0f;
+    uint64_t current_time = SDL_GetPerformanceCounter();
+    return (current_time - first_time_) / static_cast<float>(frequency_);
+  }
+  
+  /**
+   * @brief Reset the timing state
+   */
+  void Reset() {
+    last_time_ = 0;
+    first_time_ = SDL_GetPerformanceCounter();
+    accumulated_time_ = 0.0f;
+    frame_count_ = 0;
+    fps_ = 0.0f;
+    last_delta_time_ = 0.0f;
+  }
+
+ private:
+  TimingManager() {
+    frequency_ = SDL_GetPerformanceFrequency();
+    first_time_ = SDL_GetPerformanceCounter();
+    last_time_ = 0;
+    accumulated_time_ = 0.0f;
+    frame_count_ = 0;
+    fps_ = 0.0f;
+    last_delta_time_ = 0.0f;
+  }
+
+  uint64_t frequency_;
+  uint64_t first_time_;
+  uint64_t last_time_;
+  float accumulated_time_;
+  uint32_t frame_count_;
+  float fps_;
+  float last_delta_time_;
+
+  TimingManager(const TimingManager&) = delete;
+  TimingManager& operator=(const TimingManager&) = delete;
+};
+
+}  // namespace yaze
+
+#endif  // YAZE_APP_CORE_TIMING_H
+