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#pragma once
#include "TimeStamp.h"
namespace nCine
{
/// Frame interval and average FPS calculator
class FrameTimer
{
public:
/** @brief Frames per second */
static constexpr float FramesPerSecond = 60.0f;
/** @brief Seconds per frame */
static constexpr float SecondsPerFrame = 1.0f / FramesPerSecond;
/// Constructor
FrameTimer(float logInterval, float avgInterval);
/// Adds a frame to the counter and calculates the interval since the previous one
void AddFrame();
/// Starts counting the suspension time
void Suspend();
/// Drifts timers by the duration of last suspension
/*! \return A timestamp with last suspension duration */
TimeStamp Resume();
/// Returns the total number of frames counted
inline std::uint32_t GetTotalNumberFrames() const {
return _totNumFrames;
}
/// Returns the last frame duration in seconds between the last two subsequent calls to `addFrame()`
inline float GetLastFrameDuration() const {
return _frameDuration;
}
/// Returns current frame duration in seconds since the last call to `addFrame()`
inline float GetFrameDuration() const {
return _frameStart.secondsSince();
}
/// Returns current frame duration in ticks since the last call to `addFrame()`
inline std::uint64_t GetFrameDurationAsTicks() const {
return _frameStart.timeSince().ticks();
}
/// Returns the average FPS during the update interval
inline float GetAverageFps() const {
return _avgFps;
}
/// Returns a factor that represents how long the last frame took relative to the desired frame time
inline float GetTimeMult() const {
return _timeMults[0];
}
private:
/// Number of seconds between two average FPS calculations (user defined)
float _averageInterval;
/// Number of seconds between two logging events (user defined)
float _loggingInterval;
/// Timestamp at the beginning of a frame
TimeStamp _frameStart;
/// Last frame duration in seconds
float _frameDuration;
/// Timestamp at the begininng of application suspension
TimeStamp _suspensionStart;
/// Total number of frames counted
std::uint32_t _totNumFrames;
/// Frame counter for average FPS calculation
std::uint32_t _avgNumFrames;
/// Frame counter for logging
std::uint32_t _logNumFrames;
/// Time stamp at last average FPS calculation
TimeStamp _lastAvgUpdate;
/// Time stamp at last log event
TimeStamp _lastLogUpdate;
/// Average FPS calulated during the specified interval
float _avgFps;
/// Factor that represents how long the last frame took relative to the desired frame time
float _timeMults[3];
};
}
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