Special-case VCA at 0 (-inf dB), force gain slaves to -inf dB

4 files changed, 14 insertions, 6 deletions

diff --git a/libs/ardour/ardour/gain_control.h b/libs/ardour/ardour/gain_control.h
index 0a7bddcf4f..42465cc225 100644
--- a/libs/ardour/ardour/gain_control.h
+++ b/libs/ardour/ardour/gain_control.h
@@ -51,6 +51,7 @@ class LIBARDOUR_API GainControl : public SlavableAutomationControl {
 	void inc_gain (gain_t);
 
 protected:
+	void post_add_master (boost::shared_ptr<AutomationControl>);
 	bool get_masters_curve_locked (framepos_t, framepos_t, float*, framecnt_t) const;
 };
 
diff --git a/libs/ardour/ardour/slavable_automation_control.h b/libs/ardour/ardour/slavable_automation_control.h
index 4a3c990147..5057ef4070 100644
--- a/libs/ardour/ardour/slavable_automation_control.h
+++ b/libs/ardour/ardour/slavable_automation_control.h
@@ -99,9 +99,9 @@ protected:
 
 		double val_ctrl () const { return _val_ctrl; }
 		double val_master () const { return _val_master; }
-		double val_master_inv () const { return _val_master == 0 ? 1.0 : 1.0 / _val_master; }
 
-		double master_ratio () const { return _val_master == 0 ? master()->get_value() : master()->get_value() / _val_master; }
+		double val_master_inv () const { return _val_master == 0 ? 0 : 1.0 / _val_master; }
+		double master_ratio () const { return _val_master == 0 ? 0 : master()->get_value() / _val_master; }
 
 		int set_state (XMLNode const&, int);
 
diff --git a/libs/ardour/gain_control.cc b/libs/ardour/gain_control.cc
index ee356b017c..7b0f4e404c 100644
--- a/libs/ardour/gain_control.cc
+++ b/libs/ardour/gain_control.cc
@@ -102,6 +102,15 @@ GainControl::inc_gain (gain_t factor)
 	}
 }
 
+void
+GainControl::post_add_master (boost::shared_ptr<AutomationControl> m)
+{
+	if (m->get_value() == 0) {
+		/* master is at -inf, which forces this ctrl to -inf on assignment */
+		Changed (false, Controllable::NoGroup); /* EMIT SIGNAL */
+	}
+}
+
 bool
 GainControl::get_masters_curve_locked (framepos_t start, framepos_t end, float* vec, framecnt_t veclen) const
 {
diff --git a/libs/ardour/slavable_automation_control.cc b/libs/ardour/slavable_automation_control.cc
index 46b86c7cf5..cb88d36fe9 100644
--- a/libs/ardour/slavable_automation_control.cc
+++ b/libs/ardour/slavable_automation_control.cc
@@ -150,9 +150,7 @@ SlavableAutomationControl::masters_curve_multiply (framepos_t start, framepos_t
 			= boost::dynamic_pointer_cast<SlavableAutomationControl>(mr->second.master());
 		assert (sc);
 		rv |= sc->masters_curve_multiply (start, end, vec, veclen);
-		if (mr->second.val_master () != 0) {
-			apply_gain_to_buffer (vec, veclen, 1.f / mr->second.val_master ());
-		}
+		apply_gain_to_buffer (vec, veclen, mr->second.val_master_inv ());
 	}
 	return rv;
 }
@@ -166,7 +164,7 @@ SlavableAutomationControl::reduce_by_masters_locked (double value, bool ignore_a
 			/* need to scale given value by current master's scaling */
 			const double masters_value = get_masters_value_locked();
 			if (masters_value == 0.0) {
-				value = 0.0; // XXX 1.0, see master_ratio(), val_master_inv()
+				value = 0.0;
 			} else {
 				value /= masters_value;
 				value = std::max (lower(), std::min(upper(), value));