Add pause on unfocus feature

include/dusk/audio/DuskAudioSystem.h

@@ -12,6 +12,8 @@ namespace dusk::audio {
 
     void SetMasterVolume(f32 value);
 
+    void SetPaused(bool paused);
+
     u32 GetResetCount(int channelIdx);
 
     f32 VolumeFromU16(u16 value);

include/dusk/game_clock.h

@@ -8,6 +8,7 @@ namespace game_clock {
 
 void ensure_initialized();
 void reset_accumulator();
+void reset_frame_timer();
 
 constexpr float sim_pace() { return 1.0f / 30.0f; }
 constexpr float period_for_original_frames(float frame_count) { return frame_count * sim_pace(); }

include/dusk/main.h

@@ -5,6 +5,7 @@ namespace dusk {
     extern bool IsRunning;
     extern bool IsShuttingDown;
     extern bool IsGameLaunched;
+    extern bool IsFocusPaused;
 }
 
 #endif  // DUSK_MAIN_H

include/dusk/settings.h

@@ -68,6 +68,7 @@ struct UserSettings {
         ConfigVar<bool> enableMirrorMode;
         ConfigVar<bool> invertCameraXAxis;
         ConfigVar<bool> disableMainHUD;
+        ConfigVar<bool> pauseOnFocusLost;
 
         // Graphics
         ConfigVar<BloomMode> bloomMode;