From 8803cd664ce7554ba42417b326de2d0b0c407549 Mon Sep 17 00:00:00 2001 From: Paul Davis Date: Fri, 26 Jun 2015 22:15:51 -0400 Subject: a more-likely-to-be-correct version of swing quantization. This needs to be converted to fixed point, still. --- libs/ardour/quantize.cc | 106 ++++++++++++++++++++++++++++++++++-------------- 1 file changed, 76 insertions(+), 30 deletions(-) (limited to 'libs') diff --git a/libs/ardour/quantize.cc b/libs/ardour/quantize.cc index 163bb66f62..bcce41c96d 100644 --- a/libs/ardour/quantize.cc +++ b/libs/ardour/quantize.cc @@ -52,6 +52,63 @@ Quantize::~Quantize () { } +static double +swing_position (double pos, double grid, double swing, double offset) +{ + /* beats start out numbered at zero. + * + * every other position on the start-quantize-grid is + * optionally swung, meaning that its position is moved + * somewhere between its natural position and 2/3 of + * the way to the next start-quantize-grid position. + * + * so, if the _start grid is 0.5, the beat at 0 isn't + * swung, but something at 0.5 is, the beat at 1 isn't + * swung, but something at 1.5 is. + * + * if the start grid is 1.0, the beat at 0 isn't swung, + * but the beat at 1.0 is. the beat at 2.0 isn't swung, + * but the beat at 3.0 is. and so on. + * + * so the criterion for a position being swung is + * whether or not ((possible_grid_position / grid) % 2) != 0 + */ + + const bool swing_quantize_grid_position = pos > 0.0 && fmod ((pos/grid), 2.0) != 0; + const bool swing_previous_grid_position = pos > grid && fmod ((pos-grid)/grid, 2.0) != 0; + + /* one of these will not be subject to swing */ + + double swung_pos = pos; + double swung_previous_grid_position; + + if (pos > grid) { + swung_previous_grid_position = pos - grid; + } else { + swung_previous_grid_position = 0.0; + } + + if (swing_previous_grid_position) { + swung_previous_grid_position = swung_previous_grid_position + (2.0/3.0 * swing * grid); + } + + if (swing_quantize_grid_position) { + swung_pos = swung_pos + (2.0/3.0 * swing * grid); + } + + /* now correct for start-of-model offset */ + + pos += offset; + + if (fabs (pos - swung_pos) > fabs (pos - swung_previous_grid_position)) { + pos = swung_previous_grid_position; + } else { + pos = swung_pos; + } + + return pos; +} + Command* Quantize::operator () (boost::shared_ptr model, Evoral::Beats position, @@ -66,47 +123,38 @@ Quantize::operator () (boost::shared_ptr model, const double round_pos = round(position.to_double() / _start_grid) * _start_grid; const double offset = round_pos - position.to_double(); - bool even; MidiModel::NoteDiffCommand* cmd = new MidiModel::NoteDiffCommand (model, "quantize"); for (std::vector::Notes>::iterator s = seqs.begin(); s != seqs.end(); ++s) { - even = false; -; - /* TODO 'swing' probably requires a 2nd iteration: - * first quantize notes to the grid, then apply beat shift - */ for (Evoral::Sequence::Notes::iterator i = (*s).begin(); i != (*s).end(); ++i) { - double new_start = round (((*i)->time().to_double() - offset) / _start_grid) * _start_grid + offset; - double new_end = round (((*i)->end_time().to_double() - offset) / _end_grid) * _end_grid + offset; - - if (_swing > 0.0 && even) { - - double next_grid = new_start + _start_grid; - - /* find a spot 2/3 (* swing factor) of the way between the grid point - we would put this note at, and the nominal position of the next note. - */ + /* compute new start + end points WITHOUT the offset + * caused by the start of the model (see above). + * + * these versions of new_start and new_end are + * guaranteed to precisely align with the quantize grid(s). + */ + + double new_start = round (((*i)->time().to_double() - offset) / _start_grid) * _start_grid; + double new_end = round (((*i)->end_time().to_double() - offset) / _end_grid) * _end_grid; - new_start = new_start + (2.0/3.0 * _swing * (next_grid - new_start)); - new_end = new_end + (2.0/3.0 * _swing * (next_grid - new_start)); + if (_swing) { - } else if (_swing < 0.0 && even) { + new_start = swing_position (new_start, _start_grid, _swing, offset); + new_end = swing_position (new_end, _end_grid, _swing, offset); + + } else { - double prev_grid = new_start - _start_grid; - - /* find a spot 2/3 (* swing factor) of the way between the grid point - we would put this note at, and the nominal position of the previous note. - */ - - new_start = new_start - (2.0/3.0 * _swing * (new_start - prev_grid)); - new_end = new_end - (2.0/3.0 * _swing * (new_start - prev_grid)); + /* now correct for start-of-model offset */ + new_start += offset; + new_end += offset; } - + double delta = new_start - (*i)->time().to_double(); + if (fabs (delta) >= _threshold) { if (_snap_start) { delta *= _strength; @@ -128,8 +176,6 @@ Quantize::operator () (boost::shared_ptr model, cmd->change ((*i), MidiModel::NoteDiffCommand::Length, new_dur); } } - - even = !even; } } -- cgit v1.2.3