From bfd126e73bb53bcba982a21fd8bcb088da20e1dd Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Wed, 11 Jan 2012 15:07:12 +0000
Subject: [PATCH] backport click latency correction change from a3

git-svn-id: svn://localhost/ardour2/branches/2.0-ongoing@11227 d708f5d6-7413-0410-9779-e7cbd77b26cf
---
 libs/ardour/ardour/session.h |  1 +
 libs/ardour/session_click.cc | 18 ++++++++++++++----
 libs/ardour/session_state.cc |  1 +
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index d467e99354..f2080c7040 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -1729,6 +1729,7 @@ class Session : public PBD::StatefulDestructible
 	nframes_t  click_length;
 	nframes_t  click_emphasis_length;
 	mutable Glib::RWLock click_lock;
+        nframes_t  _clicks_cleared;
 
 	static const Sample         default_click[];
 	static const nframes_t default_click_length;
diff --git a/libs/ardour/session_click.cc b/libs/ardour/session_click.cc
index 7dbfe4d406..ccc26b75c0 100644
--- a/libs/ardour/session_click.cc
+++ b/libs/ardour/session_click.cc
@@ -42,19 +42,28 @@ Session::click (nframes_t start, nframes_t nframes)
 	nframes_t end;
 	Sample *buf;
 	vector<Sample*> bufs;
+        nframes_t click_distance;
 
 	if (_click_io == 0) {
 		return;
 	}
 
 	Glib::RWLock::WriterLock clickm (click_lock, Glib::TRY_LOCK);
-	
-	if (!clickm.locked() || _transport_speed != 1.0 || !_clicking || click_data == 0) {
+        
+        click_distance = start - _clicks_cleared;
+
+	if (!clickm.locked() || _transport_speed != 1.0 || !_clicking || click_data == 0 || ((click_distance + nframes) < _worst_track_latency)) {
 		_click_io->silence (nframes);
 		return;
 	} 
-
-	end = start + nframes;
+                
+        if (start < _worst_track_latency) {
+                end = start + (_worst_track_latency - start);
+                start = 0;
+        } else {
+                start -= _worst_track_latency;
+                end = start + nframes;
+        }
 
 	buf = _passthru_buffers[0];
 	points = _tempo_map->get_points (start, end);
@@ -221,4 +230,5 @@ Session::clear_clicks ()
 	}
 
 	clicks.clear ();
+        _clicks_cleared = _transport_frame;
 }
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index a52732a8b2..8b833d5157 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -203,6 +203,7 @@ Session::first_stage_init (string fullpath, string snapshot_name)
 	first_file_data_format_reset = true;
 	first_file_header_format_reset = true;
 	butler_thread = (pthread_t) 0;
+        _clicks_cleared = 0;
 
 	AudioDiskstream::allocate_working_buffers();