Add support for MainOutVolume in main-outs delivery

libs/ardour/ardour/delivery.h

@@ -29,6 +29,7 @@
 #include "ardour/types.h"
 #include "ardour/chan_count.h"
 #include "ardour/io_processor.h"
+#include "ardour/gain_control.h"
 
 namespace ARDOUR {
 
@@ -100,6 +101,10 @@ public:
 	boost::shared_ptr<PannerShell> panner_shell() const { return _panshell; }
 	boost::shared_ptr<Panner> panner() const;
 
+	void add_gain (boost::shared_ptr<GainControl> gc) {
+		_gain_control = gc;
+	}
+
 	void unpan ();
 	void reset_panner ();
 	void defer_pan_reset ();
@@ -116,14 +121,13 @@ protected:
 	gain_t      _current_gain;
 	boost::shared_ptr<PannerShell> _panshell;
 
-#ifdef MIXBUS
-public: /* expose target_gain to mixbus processor Route::process_output_buffers */
-#endif
 	gain_t target_gain ();
 
 private:
-	bool        _no_outs_cuz_we_no_monitor;
-	boost::shared_ptr<MuteMaster> _mute_master;
+	bool _no_outs_cuz_we_no_monitor;
+
+	boost::shared_ptr<MuteMaster>  _mute_master;
+	boost::shared_ptr<GainControl> _gain_control;
 
 	static bool panners_legal;
 	static PBD::Signal0<void> PannersLegal;

libs/ardour/delivery.cc

@@ -571,6 +571,10 @@ Delivery::target_gain ()
 
 	gain_t desired_gain = _mute_master->mute_gain_at (mp);
 
+	if (_gain_control) {
+		desired_gain *= _gain_control->get_value();
+	}
+
 	if (_role == Listen && _session.monitor_out() && !_session.listening()) {
 
 		/* nobody is soloed, and this delivery is a listen-send to the

libs/ardour/gain_control.cc

@@ -35,10 +35,49 @@
 using namespace ARDOUR;
 using namespace std;
 
+static std::string gain_control_name (Evoral::Parameter const& param)
+{
+	switch (param.type()) {
+		case GainAutomation:
+			/* fallthrough */
+		case BusSendLevel:
+			return X_("gaincontrol");
+		case TrimAutomation:
+			return X_("trimcontrol");
+		case MainOutVolume:
+			return X_("mastervolume");
+		default:
+			break;
+	}
+	/* default in AutomationControl c'tor uses
+	 * EventTypeMap::instance().to_symbol(parameter)
+	 */
+	return "";
+}
+
+static boost::shared_ptr<AutomationList> automation_list_new (Evoral::Parameter const& param)
+{
+	switch (param.type()) {
+		case GainAutomation:
+			/* fallthrough */
+		case BusSendLevel:
+			/* fallthrough */
+		case TrimAutomation:
+			return boost::shared_ptr<AutomationList> (new AutomationList (param));
+		case MainOutVolume:
+			/* not automatable */
+			break;
+		default:
+			assert (0);
+			break;
+	}
+	return boost::shared_ptr<AutomationList> ();
+}
+
 GainControl::GainControl (Session& session, const Evoral::Parameter &param, boost::shared_ptr<AutomationList> al)
 	: SlavableAutomationControl (session, param, ParameterDescriptor(param),
-	                             al ? al : boost::shared_ptr<AutomationList> (new AutomationList (param)),
-	                             (param.type() == GainAutomation || param.type() == BusSendLevel) ? X_("gaincontrol") : X_("trimcontrol"),
+	                             al ? al : automation_list_new (param),
+	                             gain_control_name (param),
 	                             Controllable::GainLike)
 {
 }