first pass at internal sends. this is a very tentative work in progress, and it is possible that major changes may follow in the near future. it is certainly not complete, but the fundamental changes to Port/Buffer operation merit a commit at this point

git-svn-id: svn://localhost/ardour2/branches/3.0@4464 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 84 insertions, 42 deletions

diff --git a/libs/ardour/audio_port.cc b/libs/ardour/audio_port.cc
index 55d65d850d..0e48c2a699 100644
--- a/libs/ardour/audio_port.cc
+++ b/libs/ardour/audio_port.cc
@@ -29,9 +29,10 @@ AudioPort::AudioPort (const std::string& name, Flags flags, bool ext, nframes_t
 	: Port (name, DataType::AUDIO, flags, ext)
 	, _has_been_mixed_down (false)
 	, _buffer (0)
+	, _internal_buffer (false)
 {
 	assert (name.find_first_of (':') == string::npos);
-	
+
 	if (external ()) {
 		
 		/* external ports use the external port buffer */
@@ -41,8 +42,9 @@ AudioPort::AudioPort (const std::string& name, Flags flags, bool ext, nframes_t
 
 		/* internal ports need their own buffers */
 		_buffer = new AudioBuffer (capacity);
-		
 	}
+
+	check_buffer_status ();
 	
 }
 
@@ -56,11 +58,22 @@ AudioPort::cycle_start (nframes_t nframes, nframes_t offset)
 {
 	/* caller must hold process lock */
 
-	_has_been_mixed_down = false;
+	/* For external (JACK) ports, get_buffer() must only be run 
+	   on outputs here in cycle_start().
 
-	if (external ()) {
-		/* external ports use JACK's memory */
-		_buffer->set_data ((Sample *) jack_port_get_buffer (_jack_port, nframes), nframes + offset);
+	   Inputs must be done in the correct processing order, which 
+	   requires interleaving with route processing. that will 
+	   happen when Port::get_buffer() is called.
+	*/
+	
+	if (!receives_input() && external ()) {
+		_buffer->set_data ((Sample *) jack_port_get_buffer (_jack_port, nframes) + offset, nframes);
+	}
+
+	if (receives_input()) {
+		_has_been_mixed_down = false;
+	} else {
+		_buffer->silence (nframes, offset);
 	}
 }
 
@@ -69,36 +82,21 @@ AudioPort::get_audio_buffer (nframes_t nframes, nframes_t offset)
 {
 	/* caller must hold process lock */
 
-	if (_has_been_mixed_down) {
-		return *_buffer;
-	}
-
-	if (receives_input ()) {
-
-		/* INPUT */
+	if (receives_input () && !_has_been_mixed_down) {
 
-		/* If we're external (), we have some data in our buffer set up by JACK;
-		   otherwise, we have an undefined buffer.  In either case we mix down
-		   our non-JACK inputs; either accumulating into the JACK data or
-		   overwriting the undefined data */
-		   
-		mixdown (nframes, offset, !external ());
+		/* external ports use JACK's memory unless otherwise noted */
 		
-	} else {
-
-		/* OUTPUT */
-
-		if (!external ()) {
-			/* start internal output buffers with silence */
-			_buffer->silence (nframes, offset);
+		if (external()) {
+			if (!using_internal_data()) {
+				_buffer->set_data ((Sample *) jack_port_get_buffer (_jack_port, nframes) + offset, nframes);
+			} else {
+				_buffer->silence (nframes, offset);
+			}
 		}
-		
-	}
-	
-	if (nframes) {
-		_has_been_mixed_down = true;
-	}
 
+		mixdown (nframes, offset, !external ());
+	} 
+	
 	return *_buffer;
 }
 
@@ -111,22 +109,46 @@ AudioPort::cycle_end (nframes_t nframes, nframes_t offset)
 void
 AudioPort::mixdown (nframes_t cnt, nframes_t offset, bool first_overwrite)
 {
+	/* note: this is only called for input ports */
+
 	if (_connections.empty()) {
-		if (first_overwrite) {
+
+		/* no internal mixing to do, so for internal ports
+		   just make sure the buffer is silent.
+		*/
+		
+		if (!external()) {
 			_buffer->silence (cnt, offset);
+		} 
+
+	} else {
+
+		set<Port*>::const_iterator p = _connections.begin();
+
+		/* mix in internally-connected ports. if this is an external port
+		   then it may already have data present from JACK. in that case, we 
+		   do not want to overwrite that data, so we skip the initial ::read_from()
+		   call and do everything with accumulate_from()
+		 */
+
+		if (!external()) {
+			_buffer->read_from (dynamic_cast<AudioPort*>(*p)->get_audio_buffer (cnt, offset), cnt, offset);
+			++p;
+			
 		}
-		return;
-	}
-	
-	set<Port*>::const_iterator p = _connections.begin();
 
-	if (first_overwrite) {
-		_buffer->read_from (dynamic_cast<AudioPort*>(*p)->get_audio_buffer (cnt, offset), cnt, offset);
-		++p;
+		for (; p != _connections.end (); ++p) {
+			_buffer->accumulate_from (dynamic_cast<AudioPort*>(*p)->get_audio_buffer (cnt, offset), cnt, offset);
+
+		}
 	}
 
-	for (; p != _connections.end (); ++p) {
-		_buffer->accumulate_from (dynamic_cast<AudioPort*>(*p)->get_audio_buffer (cnt, offset), cnt, offset);
+	/* XXX horrible heuristic designed to check that we worked the whole buffer.
+	   Needs fixing but its a hard problem.
+	*/
+
+	if (cnt && offset == 0) {
+		_has_been_mixed_down = true;
 	}
 }
 
@@ -140,3 +162,23 @@ AudioPort::reset ()
 		_buffer->clear ();
 	}
 }
+
+bool
+AudioPort::using_internal_data () const
+{
+	return _internal_buffer;
+}
+
+void
+AudioPort::use_internal_data ()
+{
+	_buffer->replace_data (_buffer->capacity());
+	_internal_buffer = true;
+}
+
+void
+AudioPort::use_external_data ()
+{
+	_internal_buffer = false;
+	_buffer->drop_data ();
+}