diff options
Diffstat (limited to 'libs/ardour/tempo.cc')
| -rw-r--r-- | libs/ardour/tempo.cc | 204 |
1 files changed, 202 insertions, 2 deletions
diff --git a/libs/ardour/tempo.cc b/libs/ardour/tempo.cc index adb207c752..90a428b9a0 100644 --- a/libs/ardour/tempo.cc +++ b/libs/ardour/tempo.cc @@ -1510,10 +1510,10 @@ TempoMap::get_points (framepos_t lower, framepos_t upper) const } const TempoSection& -TempoMap::tempo_section_at (framepos_t frame) +TempoMap::tempo_section_at (framepos_t frame) const { Glib::RWLock::ReaderLock lm (lock); - Metrics::iterator i; + Metrics::const_iterator i; TempoSection* prev = 0; for (i = metrics->begin(); i != metrics->end(); ++i) { @@ -1904,6 +1904,206 @@ TempoMap::bbt_subtract (const BBT_Time& start, const BBT_Time& decrement) const return result; } +/** + * add the BBT interval @param increment to @param start and return the result + */ +framepos_t +TempoMap::framepos_plus_bbt (framepos_t pos, BBT_Time op) const +{ + Metrics::const_iterator i; + const MeterSection* meter; + const MeterSection* m; + const TempoSection* tempo; + const TempoSection* t; + framecnt_t frames_per_beat; + + meter = &first_meter (); + tempo = &first_tempo (); + + assert (meter); + assert (tempo); + + /* find the starting metrics for tempo & meter */ + + for (i = metrics->begin(); i != metrics->end(); ++i) { + + if ((*i)->frame() > pos) { + break; + } + + if ((t = dynamic_cast<const TempoSection*>(*i)) != 0) { + tempo = t; + } else if ((m = dynamic_cast<const MeterSection*>(*i)) != 0) { + meter = m; + } + } + + /* We now have: + + meter -> the Meter for "pos" + tempo -> the Tempo for "pos" + i -> for first new metric after "pos", possibly metrics->end() + */ + + /* now comes the complicated part. we have to add one beat a time, + checking for a new metric on every beat. + */ + + frames_per_beat = tempo->frames_per_beat (_frame_rate, *meter); + + while (op.bars) { + + pos += llrint (frames_per_beat * meter->beats_per_bar()); + op.bars--; + + /* check if we need to use a new metric section: has adding frames moved us + to or after the start of the next metric section? in which case, use it. + */ + + if (i != metrics->end()) { + if ((*i)->frame() <= pos) { + + if ((t = dynamic_cast<const TempoSection*>(*i)) != 0) { + tempo = t; + } else if ((m = dynamic_cast<const MeterSection*>(*i)) != 0) { + meter = m; + } + ++i; + frames_per_beat = tempo->frames_per_beat (_frame_rate, *meter); + + } + } + + } + + while (op.beats) { + + /* given the current meter, have we gone past the end of the bar ? */ + + pos += frames_per_beat; + op.beats--; + + /* check if we need to use a new metric section: has adding frames moved us + to or after the start of the next metric section? in which case, use it. + */ + + if (i != metrics->end()) { + if ((*i)->frame() <= pos) { + + if ((t = dynamic_cast<const TempoSection*>(*i)) != 0) { + tempo = t; + } else if ((m = dynamic_cast<const MeterSection*>(*i)) != 0) { + meter = m; + } + ++i; + frames_per_beat = tempo->frames_per_beat (_frame_rate, *meter); + } + } + } + + if (op.ticks) { + if (op.ticks >= Meter::ticks_per_beat) { + pos += frames_per_beat; + pos += llrint (frames_per_beat * ((op.ticks % (uint32_t) Meter::ticks_per_beat) / (double) Meter::ticks_per_beat)); + } else { + pos += llrint (frames_per_beat * (op.ticks / (double) Meter::ticks_per_beat)); + } + } + + return pos; +} + +/** + * add the BBT interval @param increment to @param start and return the result + */ +double +TempoMap::framewalk_to_beats (framepos_t pos, framecnt_t distance) const +{ + Metrics::const_iterator i; + double beats = 0; + const MeterSection* meter; + const MeterSection* m; + const TempoSection* tempo; + const TempoSection* t; + double frames_per_beat; + + double ddist = distance; + double dpos = pos; + + meter = &first_meter (); + tempo = &first_tempo (); + + assert (meter); + assert (tempo); + + /* find the starting metrics for tempo & meter */ + + for (i = metrics->begin(); i != metrics->end(); ++i) { + + if ((*i)->frame() > pos) { + break; + } + + if ((t = dynamic_cast<const TempoSection*>(*i)) != 0) { + tempo = t; + } else if ((m = dynamic_cast<const MeterSection*>(*i)) != 0) { + meter = m; + } + } + + /* We now have: + + meter -> the Meter for "pos" + tempo -> the Tempo for "pos" + i -> for first new metric after "pos", possibly metrics->end() + */ + + /* now comes the complicated part. we have to add one beat a time, + checking for a new metric on every beat. + */ + + frames_per_beat = tempo->frames_per_beat (_frame_rate, *meter); + + while (ddist > 0) { + + /* if we're nearly at the end, but have a fractional beat left, + compute the fraction and then its all over + */ + + if (ddist < frames_per_beat) { + beats += Meter::ticks_per_beat * (ddist/frames_per_beat); + break; + } + + /* walk one beat */ + + ddist -= frames_per_beat; + dpos += frames_per_beat; + beats += 1.0; + + /* check if we need to use a new metric section: has adding frames moved us + to or after the start of the next metric section? in which case, use it. + */ + + if (i != metrics->end()) { + if ((*i)->frame() <= (framepos_t) dpos) { + + if ((t = dynamic_cast<const TempoSection*>(*i)) != 0) { + tempo = t; + } else if ((m = dynamic_cast<const MeterSection*>(*i)) != 0) { + meter = m; + } + ++i; + frames_per_beat = tempo->frames_per_beat (_frame_rate, *meter); + } + } + + } + + return beats; +} + + /** Compare the time of this with that of another MetricSection. * @param with_bbt True to compare using ::start(), false to use ::frame(). * @return -1 for less than, 0 for equal, 1 for greater than. |