ticker.cc

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/*
    Copyright (C) 2008 Hans Baier

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "pbd/compose.h"
#include "pbd/stacktrace.h"

#include "evoral/midi_events.h"

#include "ardour/async_midi_port.h"
#include "ardour/audioengine.h"
#include "ardour/midi_buffer.h"
#include "ardour/midi_port.h"
#include "ardour/lmath.h"
#include "ardour/ticker.h"
#include "ardour/session.h"
#include "ardour/tempo.h"
#include "ardour/debug.h"

using namespace ARDOUR;
using namespace PBD;

class MidiClockTicker::Position : public Timecode::BBT_Time
{
public:

    Position() : speed(0.0f), frame(0), midi_beats(0) { }
    ~Position() { }
    
    bool sync (Session* s) {

            bool changed = false;
            
            double     sp = s->transport_speed();
            framecnt_t fr = s->transport_frame();
            
            if (speed != sp) {
                    speed = sp;
                    changed = true;
            }

            if (frame != fr) {
                    frame = fr;
                    changed = true;
            }

            /* Midi beats and clocks always gets updated for now */

            s->bbt_time (this->frame, *this);

            const TempoMap& tempo = s->tempo_map();

            const double divisions   = tempo.meter_at(frame).divisions_per_bar();
            const double divisor     = tempo.meter_at(frame).note_divisor();
            const double qnote_scale = divisor * 0.25f;
            double mb;

            mb  = (((bars - 1) * divisions) + beats - 1);
            mb += (double)ticks / (double)Position::ticks_per_beat * qnote_scale;
            mb *= 16.0f / divisor;

            if (mb != midi_beats) {
                    midi_beats = mb;
                    midi_clocks = midi_beats * 6.0f;
                    changed = true;
            }

            return changed;
    }

    double      speed;
    framecnt_t  frame;
    double      midi_beats;
    double      midi_clocks;
    
    void print (std::ostream& s) {
            s << "frames: " << frame << " midi beats: " << midi_beats << " speed: " << speed;
    }
};


MidiClockTicker::MidiClockTicker ()
        : _ppqn (24)
        , _last_tick (0.0)
        , _send_pos (false)
        , _send_state (false)
{
        _pos.reset (new Position());
}

MidiClockTicker::~MidiClockTicker()
{
        _pos.reset (0);
}

void
MidiClockTicker::set_session (Session* s)
{
        SessionHandlePtr::set_session (s);
        
         if (_session) {
                 _session->TransportStateChange.connect_same_thread (_session_connections, boost::bind (&MidiClockTicker::transport_state_changed, this));
                 _session->TransportLooped.connect_same_thread (_session_connections, boost::bind (&MidiClockTicker::transport_looped, this));
                 _session->Located.connect_same_thread (_session_connections, boost::bind (&MidiClockTicker::session_located, this));

                 update_midi_clock_port();
                 _pos->sync (_session);
         }
}

void
MidiClockTicker::session_located()
{
        DEBUG_TRACE (DEBUG::MidiClock, string_compose ("Session Located: %1, speed: %2\n", _session->transport_frame(), _session->transport_speed()));

        if (!_session || !_pos->sync (_session)) {
                return;
        }

        _last_tick = _pos->frame;

        if (!Config->get_send_midi_clock()) {
                return;
        }

        _send_pos = true;
}

void
MidiClockTicker::session_going_away ()
{
        SessionHandlePtr::session_going_away();
        _midi_port.reset ();
}

void
MidiClockTicker::update_midi_clock_port()
{
        _midi_port = _session->midi_clock_output_port();
}

void
MidiClockTicker::transport_state_changed()
{
        if (_session->exporting()) {
                /* no midi clock during export, for now */
                return;
        }

        if (!_session->engine().running()) {
                /* Engine stopped, we can't do anything */
                return;
        }

        if (! _pos->sync (_session)) {
                return;
        }

        DEBUG_TRACE (DEBUG::MidiClock,
                 string_compose ("Transport state change @ %4, speed: %1 position: %2 play loop: %3\n",
                                                        _pos->speed, _pos->frame, _session->get_play_loop(), _pos->frame)
        );

        _last_tick = _pos->frame;

        if (! Config->get_send_midi_clock()) {
                return;
        }

        _send_state = true;

        // tick (_pos->frame);
}

void
MidiClockTicker::transport_looped()
{
        Location* loop_location = _session->locations()->auto_loop_location();
        assert(loop_location);

        DEBUG_TRACE (DEBUG::MidiClock,
                     string_compose ("Transport looped, position: %1, loop start: %2, loop end: %3, play loop: %4\n",
                                     _session->transport_frame(), loop_location->start(), loop_location->end(), _session->get_play_loop())
                );

        // adjust _last_tick, so that the next MIDI clock message is sent
        // in due time (and the tick interval is still constant)

        framecnt_t elapsed_since_last_tick = loop_location->end() - _last_tick;

        if (loop_location->start() > elapsed_since_last_tick) {
                _last_tick = loop_location->start() - elapsed_since_last_tick;
        } else {
                _last_tick = 0;
        }
}

void
MidiClockTicker::tick (const framepos_t& /* transport_frame */, pframes_t nframes)
{
        if (!Config->get_send_midi_clock() || _session == 0 || _midi_port == 0) {
                return;
        }

        if (_send_pos) {
                if (_pos->speed == 0.0f) {
                        send_position_event (llrint (_pos->midi_beats), 0, nframes);
                } else if (_pos->speed == 1.0f) {
                        send_stop_event (0, nframes);
                        
                        if (_pos->frame == 0) {
                                send_start_event (0, nframes);
                        } else {
                                send_position_event (llrint (_pos->midi_beats), 0, nframes);
                                send_continue_event (0, nframes);
                        }
                } else {
                        /* Varispeed not supported */
                }

                _send_pos = false;
        }


        if (_send_state) {
                if (_pos->speed == 1.0f) {
                        if (_session->get_play_loop()) {
                                assert(_session->locations()->auto_loop_location());
                                
                                if (_pos->frame == _session->locations()->auto_loop_location()->start()) {
                                        send_start_event (0, nframes);
                                } else {
                                        send_continue_event (0, nframes);
                                }
                                
                        } else if (_pos->frame == 0) {
                                send_start_event (0, nframes);
                        } else {
                                send_continue_event (0, nframes);
                        }
                        
                        // send_midi_clock_event (0);
                        
                } else if (_pos->speed == 0.0f) {
                        send_stop_event (0, nframes);
                        send_position_event (llrint (_pos->midi_beats), 0, nframes);
                }

                _send_state = false;
        }

        if (_session->transport_speed() != 1.0f) {
                /* no varispeed support and nothing to do after this if stopped */
                return;
        }

        const framepos_t end = _pos->frame + nframes;
        double iter = _last_tick;

        while (true) {
                double clock_delta = one_ppqn_in_frames (llrint (iter));
                double next_tick   = iter + clock_delta;
                frameoffset_t next_tick_offset = llrint (next_tick) - end;

                DEBUG_TRACE (DEBUG::MidiClock,
                                 string_compose ("Tick: iter: %1, last tick time: %2, next tick time: %3, offset: %4, cycle length: %5\n",
                                                 iter, _last_tick, next_tick, next_tick_offset, nframes));

                if (next_tick_offset >= nframes) {
                        break;
                }

                if (next_tick_offset >= 0) {
                        send_midi_clock_event (next_tick_offset, nframes);
                }

                iter = next_tick;
        }

        _last_tick  = iter;
        _pos->frame = end;
}

double
MidiClockTicker::one_ppqn_in_frames (framepos_t transport_position)
{
        const Tempo& current_tempo = _session->tempo_map().tempo_at (transport_position);
        double frames_per_beat = current_tempo.frames_per_beat (_session->nominal_frame_rate());

        double quarter_notes_per_beat = 4.0 / current_tempo.note_type();
        double frames_per_quarter_note = frames_per_beat / quarter_notes_per_beat;

        return frames_per_quarter_note / double (_ppqn);
}

void
MidiClockTicker::send_midi_clock_event (pframes_t offset, pframes_t nframes)
{
        if (!_midi_port) {
                return;
        }

        static uint8_t msg = MIDI_CMD_COMMON_CLOCK;

        MidiBuffer& mb (_midi_port->get_midi_buffer (nframes));
        mb.push_back (offset, 1, &msg);

        DEBUG_TRACE (DEBUG::MidiClock, string_compose ("Tick with offset %1\n", offset));
}

void
MidiClockTicker::send_start_event (pframes_t offset, pframes_t nframes)
{
        if (!_midi_port) {
                return;
        }

        static uint8_t msg = { MIDI_CMD_COMMON_START };
        MidiBuffer& mb (_midi_port->get_midi_buffer (nframes));
        mb.push_back (offset, 1, &msg);

        DEBUG_TRACE (DEBUG::MidiClock, string_compose ("Start %1\n", _last_tick));
}

void
MidiClockTicker::send_continue_event (pframes_t offset, pframes_t nframes)
{
        if (!_midi_port) {
                return;
        }

        static uint8_t msg = { MIDI_CMD_COMMON_CONTINUE };
        MidiBuffer& mb (_midi_port->get_midi_buffer (nframes));
        mb.push_back (offset, 1, &msg);

        DEBUG_TRACE (DEBUG::MidiClock, string_compose ("Continue %1\n", _last_tick));
}

void
MidiClockTicker::send_stop_event (pframes_t offset, pframes_t nframes)
{
        if (!_midi_port) {
                return;
        }

        static uint8_t msg = MIDI_CMD_COMMON_STOP;
        MidiBuffer& mb (_midi_port->get_midi_buffer (nframes));
        mb.push_back (offset, 1, &msg);

        DEBUG_TRACE (DEBUG::MidiClock, string_compose ("Stop %1\n", _last_tick));
}

void
MidiClockTicker::send_position_event (uint32_t midi_beats, pframes_t offset, pframes_t nframes)
{
        if (!_midi_port) {
                return;
        }

        /* can only use 14bits worth */
        if (midi_beats > 0x3fff) {
                return;
        }

        /* split midi beats into a 14bit value */
        MIDI::byte msg[3];
        msg[0] = MIDI_CMD_COMMON_SONG_POS;
        msg[1] = midi_beats & 0x007f;
        msg[2] = midi_beats >> 7;

        MidiBuffer& mb (_midi_port->get_midi_buffer (nframes));
        mb.push_back (offset, 3, &msg[0]);

        DEBUG_TRACE (DEBUG::MidiClock, string_compose ("Song Position Sent: %1 to %2 (events now %3, buf = %4)\n", midi_beats, _midi_port->name(),
                                                       mb.size(), &mb));

}