From 405f9fc712836937bf44dba48c64c1741bc4101c Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Sun, 28 Feb 2016 11:57:18 -0500
Subject: change VCA model to facilitate Harrison *and* SSL designs

---
 libs/ardour/gain_control.cc | 80 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 64 insertions(+), 16 deletions(-)

(limited to 'libs/ardour/gain_control.cc')

diff --git a/libs/ardour/gain_control.cc b/libs/ardour/gain_control.cc
index 5af0e2d397..3021151bdc 100644
--- a/libs/ardour/gain_control.cc
+++ b/libs/ardour/gain_control.cc
@@ -39,10 +39,17 @@ GainControl::GainControl (Session& session, const Evoral::Parameter &param, boos
 double
 GainControl::get_value() const
 {
-	if (!_master) {
-		return AutomationControl::get_value();
+	Glib::Threads::Mutex::Lock sm (master_lock, Glib::Threads::TRY_LOCK);
+
+	if (sm.locked()) {
+		if (_masters.empty()) {
+			return AutomationControl::get_value();
+		}
+		return AutomationControl::get_value() * get_master_gain ();
+	} else {
+		/* could not take lock */
+		return AutomationControl::get_value ();
 	}
-	return AutomationControl::get_value() * _master->get_value();
 }
 
 void
@@ -106,25 +113,49 @@ GainControl::get_user_string () const
 	return std::string(theBuf);
 }
 
-void
-GainControl::set_master (boost::shared_ptr<GainControl> m)
+gain_t
+GainControl::get_master_gain () const
 {
-	double old_master_val;
+	/* Master lock MUST be held */
 
-	if (_master) {
-		old_master_val = _master->get_value();
-	} else {
-		old_master_val = 1.0;
+	gain_t g = 1.0;
+
+	for (Masters::const_iterator m = _masters.begin(); m != _masters.end(); ++m) {
+		g *= (*m)->get_value ();
 	}
 
-	_master = m;
+	return g;
+}
 
-	double new_master_val;
+void
+GainControl::add_master (boost::shared_ptr<GainControl> m)
+{
+	gain_t old_master_val;
+	gain_t new_master_val;
+
+	{
+		Glib::Threads::Mutex::Lock lm (master_lock);
+		old_master_val = get_master_gain ();
+		_masters.push_back (m);
+		new_master_val = get_master_gain ();
+	}
 
-	if (_master) {
-		new_master_val = _master->get_value();
-	} else {
-		new_master_val = 1.0;
+	if (old_master_val != new_master_val) {
+		Changed(); /* EMIT SIGNAL */
+	}
+}
+
+void
+GainControl::remove_master (boost::shared_ptr<GainControl> m)
+{
+	gain_t old_master_val;
+	gain_t new_master_val;
+
+	{
+		Glib::Threads::Mutex::Lock lm (master_lock);
+		old_master_val = get_master_gain ();
+		_masters.remove (m);
+		new_master_val = get_master_gain ();
 	}
 
 	if (old_master_val != new_master_val) {
@@ -132,3 +163,20 @@ GainControl::set_master (boost::shared_ptr<GainControl> m)
 	}
 }
 
+void
+GainControl::clear_masters ()
+{
+	gain_t old_master_val;
+	gain_t new_master_val;
+
+	{
+		Glib::Threads::Mutex::Lock lm (master_lock);
+		old_master_val = get_master_gain ();
+		_masters.clear ();
+		new_master_val = get_master_gain ();
+	}
+
+	if (old_master_val != new_master_val) {
+		Changed(); /* EMIT SIGNAL */
+	}
+}
-- 
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