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implement TempoMap::framepos_minus_beats() using new bar|beat map structure, and fix accuracy of TempoMap::framepos_plus_bbt()

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git-svn-id: svn://localhost/ardour2/branches/3.0@11155 d708f5d6-7413-0410-9779-e7cbd77b26cf
This commit is contained in:
Paul Davis 2012-01-04 03:27:55 +00:00
parent b1a33855ce
commit 365a8f7f14
2 changed files with 48 additions and 77 deletions
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1
libs/ardour/ardour/tempo.h
View file

@ -271,6 +271,7 @@ class TempoMap : public PBD::StatefulDestructible
framepos_t framepos_plus_bbt (framepos_t pos, Timecode::BBT_Time b);
framepos_t framepos_plus_beats (framepos_t, Evoral::MusicalTime);
framepos_t framepos_minus_bbt (framepos_t pos, Timecode::BBT_Time b);
framepos_t framepos_minus_beats (framepos_t, Evoral::MusicalTime);
Evoral::MusicalTime framewalk_to_beats (framepos_t pos, framecnt_t distance);

124
libs/ardour/tempo.cc
View file

@ -1632,83 +1632,51 @@ TempoMap::framepos_plus_beats (framepos_t pos, Evoral::MusicalTime beats)
framepos_t
TempoMap::framepos_minus_beats (framepos_t pos, Evoral::MusicalTime beats)
{
Metrics::const_iterator i;
const TempoSection* tempo = 0;
const TempoSection* t;
return framepos_minus_bbt (pos, BBT_Time (beats));
}
framepos_t
TempoMap::framepos_minus_bbt (framepos_t pos, BBT_Time op)
{
BBTPointList::const_iterator i;
framecnt_t extra_frames = 0;
/* start from the bar|beat right before (or at) pos */
i = bbt_before_or_at (pos);
/* Find the starting tempo */
/* we know that (*i).frame is less than or equal to pos */
extra_frames = pos - (*i).frame;
/* walk backwards */
for (i = metrics->begin(); i != metrics->end(); ++i) {
/* This is a bit of a hack, but pos could be -ve, and if it is,
we consider the initial metric changes (at time 0) to actually
be in effect at pos.
*/
framepos_t f = (*i)->frame ();
if (pos < 0 && f == 0) {
f = pos;
}
if ((*i)->frame() > pos) {
break;
}
if ((t = dynamic_cast<const TempoSection*>(*i)) != 0) {
tempo = t;
}
}
bool no_more_tempos = false;
/* Move i back to the tempo before "pos" */
if (i != metrics->begin ()) {
while (i != metrics->begin ()) {
--i;
t = dynamic_cast<TempoSection*> (*i);
if (t) {
break;
}
}
} else {
no_more_tempos = true;
}
/* We now have:
tempo -> the Tempo for "pos"
i -> the first metric before "pos", unless no_more_tempos is true
*/
while (beats) {
/* Distance to the end of this section in frames */
framecnt_t distance_frames = no_more_tempos ? max_framepos : (pos - (*i)->frame());
/* Distance to the end in beats */
Evoral::MusicalTime distance_beats = distance_frames / tempo->frames_per_beat (_frame_rate);
/* Amount to subtract this time */
double const sub = min (distance_beats, beats);
/* Update */
beats -= sub;
pos -= sub * tempo->frames_per_beat (_frame_rate);
/* Move i and tempo back, if there's anything to move to */
if (i != metrics->begin ()) {
while (i != metrics->begin ()) {
--i;
if ((t = dynamic_cast<const TempoSection*>(*i)) != 0) {
tempo = t;
break;
}
while (i != _map.begin() && (op.bars || op.beats)) {
--i;
if ((*i).is_bar()) {
if (op.bars) {
op.bars--;
}
} else {
no_more_tempos = true;
if (op.beats) {
op.beats--;
}
}
}
/* handle ticks (assumed to be less than
* BBT_Time::ticks_per_bar_division, as always.
*/
return pos;
if (op.ticks) {
frameoffset_t tick_frames = llrint ((*i).meter->frames_per_division (*(*i).tempo, _frame_rate) * (op.ticks/BBT_Time::ticks_per_bar_division));
framepos_t pre_tick_frames = (*i).frame + extra_frames;
if (tick_frames < pre_tick_frames) {
return pre_tick_frames - tick_frames;
}
return 0;
} else {
return (*i).frame + extra_frames;
}
}
/** Add the BBT interval op to pos and return the result */
@ -1718,6 +1686,7 @@ TempoMap::framepos_plus_bbt (framepos_t pos, BBT_Time op)
BBT_Time op_copy (op);
int additional_minutes = 1;
BBTPointList::const_iterator i;
framecnt_t backup_frames = 0;
while (true) {
@ -1725,10 +1694,8 @@ TempoMap::framepos_plus_bbt (framepos_t pos, BBT_Time op)
op = op_copy;
if ((*i).frame != pos) {
/* we know that (*i).frame is before pos */
cerr << "Need to account for offset of " << (pos - (*i).frame) << endl;
}
/* we know that (*i).frame is before or equal to pos */
backup_frames = pos - (*i).frame;
while (i != _map.end() && (op.bars || op.beats)) {
++i;
@ -1754,14 +1721,17 @@ TempoMap::framepos_plus_bbt (framepos_t pos, BBT_Time op)
additional_minutes *= 2;
/* go back and try again */
cerr << "reached end of map with op now at " << op << " end = " << _map.back().frame << ' ' << _map.back().bar << '|' << _map.back().beat << ", trying to walk " << op_copy << " ... retry\n";
warning << "reached end of map with op now at " << op << " end = "
<< _map.back().frame << ' ' << _map.back().bar << '|' << _map.back().beat << ", trying to walk "
<< op_copy << " ... retry"
<< endmsg;
}
if (op.ticks) {
return (*i).frame +
return (*i).frame - backup_frames +
llrint ((*i).meter->frames_per_division (*(*i).tempo, _frame_rate) * (op.ticks/BBT_Time::ticks_per_bar_division));
} else {
return (*i).frame;
return (*i).frame - backup_frames;
}
}