Make Session::audible_frame() return a (more) correct answer when the transport has changed direction since it last started rolling. Fixes some playhead anomolies when reversing the transport.

git-svn-id: svn://localhost/ardour2/branches/3.0@6999 d708f5d6-7413-0410-9779-e7cbd77b26cf

5 files changed, 14 insertions, 5 deletions

diff --git a/gtk2_ardour/editor.cc b/gtk2_ardour/editor.cc
index 9a3a94bf8d..b4e952970b 100644
--- a/gtk2_ardour/editor.cc
+++ b/gtk2_ardour/editor.cc
@@ -5175,6 +5175,7 @@ Editor::super_rapid_screen_update ()
 	 * 1.  we don't update things when there's a pending locate request, otherwise
 	 *     when the editor requests a locate there is a chance that this method
 	 *     will move the playhead before the locate request is processed, causing
+	 *     a visual glitch.
 	 * 2.  if we're not rolling, there's nothing to do here (locates are handled elsewhere).
 	 * 3.  if we're still at the same frame that we were last time, there's nothing to do.
 	 */
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index e2f3ff1625..8f0a2504eb 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -987,6 +987,7 @@ class Session : public PBD::StatefulDestructible, public PBD::ScopedConnectionLi
 	int      load_state (std::string snapshot_name);
 
 	nframes_t _last_roll_location;
+	nframes_t _last_roll_or_reversal_location;
 	nframes_t _last_record_location;
 
 	bool              pending_locate_roll;
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 56e4660125..4ac6f9ebbc 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -1104,17 +1104,20 @@ Session::audible_frame () const
 
 		/* MOVING */
 
-		/* check to see if we have passed the first guaranteed
+		/* Check to see if we have passed the first guaranteed
 		   audible frame past our last start position. if not,
 		   return that last start point because in terms
 		   of audible frames, we have not moved yet.
+
+		   `Start position' in this context means the time we last
+		   either started or changed transport direction.
 		*/
 
 		if (_transport_speed > 0.0f) {
 
 			if (!play_loop || !have_looped) {
-				if (tf < _last_roll_location + offset) {
-					return _last_roll_location;
+				if (tf < _last_roll_or_reversal_location + offset) {
+					return _last_roll_or_reversal_location;
 				}
 			}
 
@@ -1126,8 +1129,8 @@ Session::audible_frame () const
 
 			/* XXX wot? no backward looping? */
 
-			if (tf > _last_roll_location - offset) {
-				return _last_roll_location;
+			if (tf > _last_roll_or_reversal_location - offset) {
+				return _last_roll_or_reversal_location;
 			} else {
 				/* backwards */
 				ret += offset;
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 82b5d3a249..ae2eda81d4 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -184,6 +184,7 @@ Session::first_stage_init (string fullpath, string snapshot_name)
 	play_loop = false;
 	have_looped = false;
 	_last_roll_location = 0;
+	_last_roll_or_reversal_location = 0;
 	_last_record_location = 0;
 	pending_locate_frame = 0;
 	pending_locate_roll = false;
diff --git a/libs/ardour/session_transport.cc b/libs/ardour/session_transport.cc
index aab27fe68b..6d7d3b4521 100644
--- a/libs/ardour/session_transport.cc
+++ b/libs/ardour/session_transport.cc
@@ -1012,6 +1012,7 @@ Session::set_transport_speed (double speed, bool abort, bool clear_state)
 
 		if ((_transport_speed && speed * _transport_speed < 0.0) || (_last_transport_speed * speed < 0.0) || (_last_transport_speed == 0.0f && speed < 0.0f)) {
 			todo = PostTransportWork (todo | PostTransportReverse);
+			_last_roll_or_reversal_location = _transport_frame;
 		}
 
 		_last_transport_speed = _transport_speed;
@@ -1097,6 +1098,8 @@ void
 Session::start_transport ()
 {
 	_last_roll_location = _transport_frame;
+	_last_roll_or_reversal_location = _transport_frame;
+	
 	have_looped = false;
 
 	/* if record status is Enabled, move it to Recording. if its