forked from NaiJi/project-kyoku
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
120 lines
2.4 KiB
C++
120 lines
2.4 KiB
C++
#include "tools/bpmcalculator.h"
|
|
#include <cmath>
|
|
#include <numeric>
|
|
#include <iostream>
|
|
|
|
constexpr float MICROSECONDS_IN_MINUTE_f = 60000000.;
|
|
|
|
BPMCalculator::BPMCalculator(const std::shared_ptr<Music>& music) :
|
|
_music(music)
|
|
{
|
|
reset();
|
|
}
|
|
|
|
void BPMCalculator::reset()
|
|
{
|
|
_calculating = false;
|
|
_deltas.clear();
|
|
_previous_click_offset = 0;
|
|
_approximated_bpm = 0;
|
|
_need_recalculate = true;
|
|
}
|
|
|
|
void BPMCalculator::setMusic(const std::shared_ptr<Music>& music)
|
|
{
|
|
_music = music;
|
|
reset();
|
|
}
|
|
|
|
std::shared_ptr<Music> BPMCalculator::music() const
|
|
{
|
|
return _music;
|
|
}
|
|
|
|
void BPMCalculator::start()
|
|
{
|
|
reset();
|
|
|
|
_calculating = true;
|
|
}
|
|
|
|
void BPMCalculator::stop()
|
|
{
|
|
_calculating = false;
|
|
}
|
|
|
|
void BPMCalculator::click()
|
|
{
|
|
if (!_calculating)
|
|
return;
|
|
|
|
const microsec click_offset = _music->fetchOffset();
|
|
_need_recalculate = true;
|
|
|
|
if (_previous_click_offset == 0)
|
|
{
|
|
_previous_click_offset = click_offset;
|
|
return;
|
|
}
|
|
|
|
const microsec delta = click_offset - _previous_click_offset;
|
|
_deltas.emplace_back(delta);
|
|
|
|
_previous_click_offset = click_offset;
|
|
}
|
|
|
|
float BPMCalculator::fetchCurrentBPMApproximation()
|
|
{
|
|
if (!_need_recalculate)
|
|
return _approximated_bpm;
|
|
|
|
_need_recalculate = false;
|
|
|
|
const microsec sum = std::accumulate(_deltas.begin(), _deltas.end(), 0);
|
|
bool hasEnoughDeltas = _deltas.size() >= 8;
|
|
|
|
_approximated_bpm = (!hasEnoughDeltas)
|
|
? 0.
|
|
: calculateBPM(sum, _deltas.size());
|
|
|
|
return _approximated_bpm;
|
|
}
|
|
|
|
float BPMCalculator::calculateBPM(microsec all_microseconds, std::size_t beats_amount) const
|
|
{
|
|
if (beats_amount == 0)
|
|
return 0;
|
|
|
|
float relation = static_cast<float>(all_microseconds)
|
|
/ static_cast<float>(beats_amount);
|
|
|
|
return static_cast<float>(1. / relation);
|
|
}
|
|
|
|
microsec BPMCalculator::getStartingOffset() const
|
|
{
|
|
return _first_click_offset;
|
|
}
|
|
|
|
void BPMCalculator::setStartingOffset(microsec offset)
|
|
{
|
|
_first_click_offset = offset;
|
|
}
|
|
|
|
void BPMCalculator::moveStartingOffsetBy(microsec shift)
|
|
{
|
|
_first_click_offset += shift;
|
|
}
|
|
|
|
microsec BPMCalculator::fetchTimeUntilNextBeat()
|
|
{
|
|
const microsec actual_offset = _music->fetchOffset() - _first_click_offset;
|
|
|
|
return fetchBeatInterval() % actual_offset;
|
|
}
|
|
|
|
microsec BPMCalculator::fetchBeatInterval()
|
|
{
|
|
return static_cast<microsec>(1. / fetchCurrentBPMApproximation());
|
|
}
|