Add option to limit automatable control parmaters

VCVRack VST currently exposes 9999 automatable-control parmaters.
This slows down various GUI dropdown lists and dialogs.
(even worse: those parameters are not mapped to anything by default).

This change allows to limit automatable parameters to a reasonable number,
without loosing state of already automated parameters in existing sessions.

3 files changed, 17 insertions, 6 deletions

diff --git a/libs/ardour/ardour/rc_configuration_vars.h b/libs/ardour/ardour/rc_configuration_vars.h
index 452a0822cc..365b546eb3 100644
--- a/libs/ardour/ardour/rc_configuration_vars.h
+++ b/libs/ardour/ardour/rc_configuration_vars.h
@@ -244,6 +244,7 @@ CONFIG_VARIABLE (int, vst_scan_timeout, "vst-scan-timeout", 1200) /* deciseconds
 CONFIG_VARIABLE (bool, discover_audio_units, "discover-audio-units", false)
 CONFIG_VARIABLE (bool, ask_replace_instrument, "ask-replace-instrument", true)
 CONFIG_VARIABLE (bool, ask_setup_instrument, "ask-setup-instrument", true)
+CONFIG_VARIABLE (uint32_t, limit_n_automatables, "limit-n-automatables", 512)
 
 /* custom user plugin paths */
 CONFIG_VARIABLE (std::string, plugin_path_vst, "plugin-path-vst", "@default@")
diff --git a/libs/ardour/automatable.cc b/libs/ardour/automatable.cc
index 2f60024ff0..fd7c0a9b01 100644
--- a/libs/ardour/automatable.cc
+++ b/libs/ardour/automatable.cc
@@ -240,16 +240,24 @@ Automatable::set_automation_xml_state (const XMLNode& node, Evoral::Parameter le
 				continue;
 			}
 
-			if (_can_automate_list.find (param) == _can_automate_list.end ()) {
-				warning << "Ignored automation data for non-automatable parameter" << endl;
-				continue;
-			}
-
 			if (!id_prop) {
 				warning << "AutomationList node without automation-id property, "
 					<< "using default: " << EventTypeMap::instance().to_symbol(legacy_param) << endmsg;
 			}
 
+			if (_can_automate_list.find (param) == _can_automate_list.end ()) {
+				boost::shared_ptr<AutomationControl> actl = automation_control (param);
+				if (actl && (*niter)->children().size() > 0 && Config->get_limit_n_automatables () > 0) {
+					actl->set_flags (Controllable::Flag ((int)actl->flags() & ~Controllable::NotAutomatable));
+					can_automate (param);
+					info << "Marked parmater as automatable" << endl;
+				} else {
+					warning << "Ignored automation data for non-automatable parameter" << endl;
+					continue;
+				}
+			}
+
+
 			boost::shared_ptr<AutomationControl> existing = automation_control (param);
 
 			if (existing) {
diff --git a/libs/ardour/plugin_insert.cc b/libs/ardour/plugin_insert.cc
index 2537f8d232..d5056e7259 100644
--- a/libs/ardour/plugin_insert.cc
+++ b/libs/ardour/plugin_insert.cc
@@ -434,6 +434,8 @@ PluginInsert::create_automatable_parameters ()
 	boost::shared_ptr<Plugin> plugin = _plugins.front();
 	set<Evoral::Parameter> a = _plugins.front()->automatable ();
 
+	const uint32_t limit_automatables = Config->get_limit_n_automatables ();
+
 	for (uint32_t i = 0; i < plugin->parameter_count(); ++i) {
 		if (!plugin->parameter_is_control (i)) {
 			continue;
@@ -452,7 +454,7 @@ PluginInsert::create_automatable_parameters ()
 
 		boost::shared_ptr<AutomationList> list(new AutomationList(param, desc));
 		boost::shared_ptr<AutomationControl> c (new PluginControl(this, param, desc, list));
-		if (!automatable) {
+		if (!automatable || (limit_automatables > 0 && i > limit_automatables)) {
 			c->set_flags (Controllable::Flag ((int)c->flags() | Controllable::NotAutomatable));
 		}
 		add_control (c);