some strategic documentation

[ardour.git] / libs / ardour / delivery.cc

diff --git a/libs/ardour/delivery.cc b/libs/ardour/delivery.cc
index 5a4fbd3e1defe3c1f5bf5cc481f36fefd29ebd60..b2cdc0b324b30944bfcca4c81b56e5db029ff3a5 100644 (file)
--- a/libs/ardour/delivery.cc
+++ b/libs/ardour/delivery.cc
@@ -52,7 +52,7 @@ Delivery::Delivery (Session& s, boost::shared_ptr<IO> io, boost::shared_ptr<Pann
        : IOProcessor(s, boost::shared_ptr<IO>(), (role_requires_output_ports (r) ? io : boost::shared_ptr<IO>()), name)
        , _role (r)
        , _output_buffers (new BufferSet())
-       , _amp (new Amp (s))
+       , _current_gain (GAIN_COEFF_UNITY)
        , _no_outs_cuz_we_no_monitor (false)
        , _mute_master (mm)
        , _no_panner_reset (false)
@@ -68,8 +68,6 @@ Delivery::Delivery (Session& s, boost::shared_ptr<IO> io, boost::shared_ptr<Pann
        if (_output) {
                _output->changed.connect_same_thread (*this, boost::bind (&Delivery::output_changed, this, _1, _2));
        }
-
-       _amp->activate ();
 }
 
 /* deliver to a new IO object */
@@ -78,7 +76,7 @@ Delivery::Delivery (Session& s, boost::shared_ptr<Pannable> pannable, boost::sha
        : IOProcessor(s, false, (role_requires_output_ports (r) ? true : false), name, "", DataType::AUDIO, (r == Send))
        , _role (r)
        , _output_buffers (new BufferSet())
-       , _amp (new Amp (s))
+       , _current_gain (GAIN_COEFF_UNITY)
        , _no_outs_cuz_we_no_monitor (false)
        , _mute_master (mm)
        , _no_panner_reset (false)
@@ -94,10 +92,9 @@ Delivery::Delivery (Session& s, boost::shared_ptr<Pannable> pannable, boost::sha
        if (_output) {
                _output->changed.connect_same_thread (*this, boost::bind (&Delivery::output_changed, this, _1, _2));
        }
-
-       _amp->activate ();
 }
 
+
 Delivery::~Delivery()
 {
        DEBUG_TRACE (DEBUG::Destruction, string_compose ("delivery %1 destructor\n", _name));
@@ -238,7 +235,6 @@ Delivery::run (BufferSet& bufs, framepos_t start_frame, framepos_t end_frame, pf
 
        PortSet& ports (_output->ports());
        gain_t tgain;
-       bool need_amp = true;
 
        if (_output->n_ports ().get (_output->default_type()) == 0) {
                goto out;
@@ -263,59 +259,28 @@ Delivery::run (BufferSet& bufs, framepos_t start_frame, framepos_t end_frame, pf
 
        tgain = target_gain ();
 
-       if (tgain < GAIN_COEFF_SMALL && _amp->gain() < GAIN_COEFF_SMALL) {
-
-               /* special case (but very common) fast path:
-                *
-                * if we are supposed to be silent, and we were already silent,
-                * then short-circuit the computation in Amp and just put silence into
-                * our output(s)
-                */
-
-               _output->silence (nframes);
-
-               if (!result_required) {
-                       /* if !result_required, then the buffers won't actually
-                        * be used. This means we don't actually need to silence
-                        * them, because we've already filled the output ports
-                        * with silence.
-                        *
-                        * but we just noted that result_required is true,
-                        * and so we do need to run the amp to ensure
-                        * that the buffers are silenced.
-                        */
-                       need_amp = false;
-               }
-       }
-
-       if (need_amp) {
+       if (tgain != _current_gain) {
+               /* target gain has changed */
 
-               bufs.set_count (output_buffers().count ());
+               _current_gain = Amp::apply_gain (bufs, _session.nominal_frame_rate(), nframes, _current_gain, tgain);
 
-               if (_role != Main) {
+       } else if (tgain < GAIN_COEFF_SMALL) {
 
-                       /* inserts, external and internal sends have
-                        * automatable gain and the Amp::run() method has
-                        * already been executed by the time we get here.
-                        *
-                        * XXX we do not expose the automatable gain for
-                        * Inserts as of September 2015.
-                        */
-
-               } else {
-
-                       /* main outs have no automatable gain, the amp is just
-                        * used for ramping gain changes caused by monitoring
-                        * state changes.
-                        */
-
-                       _amp->set_gain (tgain, this);
-                       _amp->run (bufs, 0, 0, nframes, false);
+               /* we were quiet last time, and we're still supposed to be quiet.
+                  Silence the outputs, and make sure the buffers are quiet too,
+               */
 
+               _output->silence (nframes);
+               if (result_required) {
+                       bufs.set_count (output_buffers().count ());
+                       Amp::apply_simple_gain (bufs, nframes, GAIN_COEFF_ZERO);
                }
-
-       } else {
                goto out;
+
+       } else if (tgain != GAIN_COEFF_UNITY) {
+
+               /* target gain has not changed, but is not unity */
+               Amp::apply_simple_gain (bufs, nframes, tgain);
        }
 
         // Speed quietning
@@ -335,7 +300,7 @@ Delivery::run (BufferSet& bufs, framepos_t start_frame, framepos_t end_frame, pf
                // MIDI data will not have been delivered by the panner
 
                if (bufs.count().n_midi() > 0 && ports.count().n_midi () > 0) {
-                       _output->copy_to_outputs (bufs, DataType::MIDI, nframes, 0);
+                       _output->copy_to_outputs (bufs, DataType::MIDI, nframes, ports.port(0)->port_offset());
                }
 
        } else {
@@ -347,7 +312,7 @@ Delivery::run (BufferSet& bufs, framepos_t start_frame, framepos_t end_frame, pf
                 }
 
                if (bufs.count().n_midi() > 0 && ports.count().n_midi () > 0) {
-                       _output->copy_to_outputs (bufs, DataType::MIDI, nframes, 0);
+                       _output->copy_to_outputs (bufs, DataType::MIDI, nframes, ports.port(0)->port_offset());
                }
        }
 
@@ -548,7 +513,7 @@ Delivery::target_gain ()
           we're not monitoring, then be quiet.
        */
 
-       if (_role == Main && _session.config.get_use_monitor_fades() && _no_outs_cuz_we_no_monitor) {
+       if (_no_outs_cuz_we_no_monitor) {
                return GAIN_COEFF_ZERO;
        }