From ba0dac92f2ac707d0ed4565ef197eed1079bb68d Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Mon, 20 Jul 2020 22:54:54 +0200
Subject: [PATCH] Add a main-outs volume control and dedicated master-volume

This is intended for loudness normalization - #8318 to add
additional gain as last step.
---
 libs/ardour/ardour/route.h   |  2 ++
 libs/ardour/ardour/session.h |  1 +
 libs/ardour/route.cc         | 19 +++++++++++++++++++
 libs/ardour/session.cc       |  9 +++++++++
 4 files changed, 31 insertions(+)

diff --git a/libs/ardour/ardour/route.h b/libs/ardour/ardour/route.h
index 7f71e35156..1d309d0970 100644
--- a/libs/ardour/ardour/route.h
+++ b/libs/ardour/ardour/route.h
@@ -500,6 +500,7 @@ public:
 
 	boost::shared_ptr<GainControl> gain_control() const;
 	boost::shared_ptr<GainControl> trim_control() const;
+	boost::shared_ptr<GainControl> volume_control() const;
 	boost::shared_ptr<PhaseControl> phase_control() const;
 
 	/**
@@ -682,6 +683,7 @@ protected:
 
 	boost::shared_ptr<GainControl>  _gain_control;
 	boost::shared_ptr<GainControl>  _trim_control;
+	boost::shared_ptr<GainControl>  _volume_control;
 	boost::shared_ptr<PhaseControl> _phase_control;
 	boost::shared_ptr<Amp>               _amp;
 	boost::shared_ptr<Amp>               _trim;
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index f0e0709839..19e1b87bf4 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -957,6 +957,7 @@ public:
 
 	boost::shared_ptr<Route> monitor_out() const { return _monitor_out; }
 	boost::shared_ptr<Route> master_out() const { return _master_out; }
+	boost::shared_ptr<GainControl>  master_volume () const;
 
 	PresentationInfo::order_t master_order_key () const { return _master_out ? _master_out->presentation_info ().order () : -1; }
 	bool ensure_stripable_sort_order ();
diff --git a/libs/ardour/route.cc b/libs/ardour/route.cc
index 1822889b91..370caa46c5 100644
--- a/libs/ardour/route.cc
+++ b/libs/ardour/route.cc
@@ -252,6 +252,13 @@ Route::init ()
 	}
 
 	_main_outs.reset (new Delivery (_session, _output, _pannable, _mute_master, _name, Delivery::Main));
+	/* master outut volume */
+	if (is_master()) {
+		_volume_control.reset (new GainControl (_session, MainOutVolume));
+		_volume_control->set_flag (Controllable::NotAutomatable);
+		//add_control (_volume_control);
+		_main_outs->add_gain (_volume_control);
+	}
 	_main_outs->activate ();
 
 	if (is_monitor()) {
@@ -2524,6 +2531,10 @@ Route::state (bool save_template)
 	node->add_child_nocopy (_mute_control->get_state ());
 	node->add_child_nocopy (_phase_control->get_state ());
 
+	if (_volume_control) {
+		node->add_child_nocopy (_volume_control->get_state ());
+	}
+
 	if (!skip_saving_automation) {
 		node->add_child_nocopy (Automatable::get_automation_xml_state ());
 	}
@@ -2761,6 +2772,8 @@ Route::set_state (const XMLNode& node, int version)
 				_solo_isolate_control->set_state (*child, version);
 			} else if (control_name == _mute_control->name()) {
 				_mute_control->set_state (*child, version);
+			} else if (_volume_control && control_name == _volume_control->name()) {
+				_volume_control->set_state (*child, version);
 			} else if (control_name == _phase_control->name()) {
 				_phase_control->set_state (*child, version);
 			} else {
@@ -4612,6 +4625,12 @@ Route::trim_control() const
 	return _trim_control;
 }
 
+boost::shared_ptr<GainControl>
+Route::volume_control() const
+{
+	return _volume_control;
+}
+
 boost::shared_ptr<PhaseControl>
 Route::phase_control() const
 {
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 8dc7ad20cc..ca6d3a0cfa 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -925,6 +925,15 @@ Session::auto_connect_master_bus ()
 	}
 }
 
+boost::shared_ptr<GainControl>
+Session::master_volume () const
+{
+	if (_master_out) {
+		return _master_out->volume_control ();
+	}
+	return boost::shared_ptr<GainControl> ();
+}
+
 void
 Session::remove_monitor_section ()
 {