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Tempo ramps - one approach to audio-locked meters.

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- audio-locked meters retain their 'home' bar position
	  unless altered by another metric.
	  this is an alternative to a more strict model
	  which isn't quite so flexible.
This commit is contained in:
nick_m 2016-04-17 02:34:40 +10:00
parent 4f8fa6787a
commit b24ce3fbe9
2 changed files with 23 additions and 14 deletions
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34
libs/ardour/tempo.cc
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@ -1288,10 +1288,16 @@ TempoMap::recompute_meters (Metrics& metrics)
if (meter->movable()) {
const double beats = ((pulse_at_frame_locked (metrics, meter->frame()) - prev_m->pulse()) * prev_m->note_divisor());
const double floor_beats = beats - fmod (beats, prev_m->divisions_per_bar());
b_bbt = make_pair (floor_beats + prev_m->beat(), BBT_Time ((floor_beats / prev_m->divisions_per_bar()) + prev_m->bbt().bars, 1, 0));
const double true_pulse = prev_m->pulse() + (floor_beats / prev_m->note_divisor());
const double pulse_off = true_pulse - (beats / prev_m->note_divisor()) - prev_m->pulse();
pulse = true_pulse - pulse_off;
if (floor_beats + prev_m->beat() < meter->beat()) {
/* tempo change caused a change in beat (bar). */
b_bbt = make_pair (floor_beats + prev_m->beat(), BBT_Time ((floor_beats / prev_m->divisions_per_bar()) + prev_m->bbt().bars, 1, 0));
const double true_pulse = prev_m->pulse() + (floor_beats / prev_m->note_divisor());
const double pulse_off = true_pulse - (beats / prev_m->note_divisor()) - prev_m->pulse();
pulse = true_pulse - pulse_off;
} else {
b_bbt = make_pair (meter->beat(), meter->bbt());
pulse = pulse_at_frame_locked (metrics, meter->frame());
}
} else {
b_bbt = make_pair (0.0, BBT_Time (1, 1, 0));
}
@ -2028,8 +2034,6 @@ TempoMap::solve_map (Metrics& imaginary, MeterSection* section, const framepos_t
}
}
section->set_frame (frame);
for (Metrics::iterator i = imaginary.begin(); i != imaginary.end(); ++i) {
MeterSection* m;
if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
@ -2037,7 +2041,7 @@ TempoMap::solve_map (Metrics& imaginary, MeterSection* section, const framepos_t
/*
here we set the beat for this frame.
we set it 'incorrectly' to the next bar's first beat
and use the delat to find the meter's pulse.
and use the delta to find the meter's pulse.
*/
double new_pulse = 0.0;
pair<double, BBT_Time> b_bbt;
@ -2045,14 +2049,20 @@ TempoMap::solve_map (Metrics& imaginary, MeterSection* section, const framepos_t
if (section->movable()) {
const double beats = ((pulse_at_frame_locked (imaginary, frame) - prev_m->pulse()) * prev_m->note_divisor());
const double floor_beats = beats - fmod (beats, prev_m->divisions_per_bar());
b_bbt = make_pair (floor_beats + prev_m->beat(), BBT_Time ((floor_beats / prev_m->divisions_per_bar()) + prev_m->bbt().bars, 1, 0));
const double true_pulse = prev_m->pulse() + (floor_beats / prev_m->note_divisor());
const double pulse_off = true_pulse - (beats / prev_m->note_divisor()) - prev_m->pulse();
new_pulse = true_pulse - pulse_off;
if (floor_beats + prev_m->beat() < section->beat()) {
/* disallow position change if it will alter out beat
we allow tempo changes to do this in recompute_meters().
blocking this is an option, but i'm not convinced that
this is what the user would actually want.
*/
return;
}
b_bbt = make_pair (section->beat(), section->bbt());
new_pulse = pulse_at_frame_locked (imaginary, frame);
} else {
b_bbt = make_pair (0.0, BBT_Time (1, 1, 0));
}
section->set_frame (frame);
section->set_beat (b_bbt);
section->set_pulse (new_pulse);
prev_m = m;