From 1674261f8900b7085c84ad64dc073ea550d25f9e Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sun, 21 Jun 2020 17:36:01 +0200
Subject: [PATCH] On plugin internal-state change, mark preset as modified

---
 libs/ardour/ardour/plugin.h |  6 ++++++
 libs/ardour/lv2_plugin.cc   |  2 +-
 libs/ardour/plugin.cc       |  8 ++++++++
 libs/ardour/session_vst.cc  | 12 ++++++++----
 4 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/libs/ardour/ardour/plugin.h b/libs/ardour/ardour/plugin.h
index e4b5d1adbe..a062cc8858 100644
--- a/libs/ardour/ardour/plugin.h
+++ b/libs/ardour/ardour/plugin.h
@@ -376,6 +376,12 @@ protected:
 	/** Do the actual removal of a preset of the provided name */
 	virtual void do_remove_preset (std::string) = 0;
 
+
+	/** Plugin's [internal] state changed, mark preset and session
+	 * as modified.
+	 */
+	void state_changed ();
+
 	ARDOUR::AudioEngine& _engine;
 	ARDOUR::Session&     _session;
 	PluginInfoPtr        _info;
diff --git a/libs/ardour/lv2_plugin.cc b/libs/ardour/lv2_plugin.cc
index f841e6e8c1..22587da4b6 100644
--- a/libs/ardour/lv2_plugin.cc
+++ b/libs/ardour/lv2_plugin.cc
@@ -2999,7 +2999,7 @@ LV2Plugin::connect_and_run(BufferSet& bufs,
 					    atom->type == _uri_map.urids.atom_Object) {
 						LV2_Atom_Object* obj = (LV2_Atom_Object*)atom;
 						if (obj->body.otype == _uri_map.urids.state_StateChanged) {
-							_session.set_dirty ();
+							Plugin::state_changed ();
 						}
 					}
 				}
diff --git a/libs/ardour/plugin.cc b/libs/ardour/plugin.cc
index b3a805b9f5..1330011173 100644
--- a/libs/ardour/plugin.cc
+++ b/libs/ardour/plugin.cc
@@ -493,6 +493,14 @@ Plugin::parameter_changed_externally (uint32_t which, float /* value */)
 	PresetDirty (); /* EMIT SIGNAL */
 }
 
+void
+Plugin::state_changed ()
+{
+	_parameter_changed_since_last_preset = true;
+	_session.set_dirty ();
+	PresetDirty (); /* EMIT SIGNAL */
+}
+
 int
 Plugin::set_state (const XMLNode& node, int /*version*/)
 {
diff --git a/libs/ardour/session_vst.cc b/libs/ardour/session_vst.cc
index af1fd01b3a..fad298fe77 100644
--- a/libs/ardour/session_vst.cc
+++ b/libs/ardour/session_vst.cc
@@ -502,10 +502,14 @@ intptr_t Session::vst_callback (
 
 	case audioMasterUpdateDisplay:
 		SHOW_CALLBACK ("audioMasterUpdateDisplay");
-		// something has changed, update 'multi-fx' display
-		/* TODO: consider emitting  ParameterChangedExternally() for each ctrl input */
-		if (session) {
-			session->set_dirty ();
+		/* Something has changed, update 'multi-fx' display.
+		 * (Ardour watches output ports already, and redraws when idle.)
+		 *
+		 * We assume that the internal state of the plugin has changed,
+		 * and session as well as preset is marked as modified.
+		 */
+		if (plug) {
+			plug->state_changed ();
 		}
 		return 0;