Added MidiControlListener for controlling LMMS via MIDI

MidiControlListener is MidiEventProcessor that listens for specific
MIDI events in order to control LMMS' transportation (currently only
start/stop). Can be advanced later to control other things in LMMS.

src/core/engine.cpp

@@ -45,6 +45,7 @@
 #include "project_notes.h"
 #include "song_editor.h"
 #include "song.h"
+#include "midi_control_listener.h"
 
 #include "resources_db.h"
 #include "local_resources_provider.h"
@@ -72,6 +73,7 @@ projectJournal * engine::s_projectJournal = NULL;
 ladspa2LMMS * engine::s_ladspaManager = NULL;
 dummyTrackContainer * engine::s_dummyTC = NULL;
 controllerRackView * engine::s_controllerRackView = NULL;
+MidiControlListener * engine::s_midiControlListener = NULL;
 QMap<QString, QString> engine::s_pluginFileHandling;
 LmmsStyle * engine::s_lmmsStyle = NULL;
 
@@ -117,6 +119,8 @@ void engine::init( const bool _has_gui )
 
 	s_mixer->initDevices();
 
+	s_midiControlListener = new MidiControlListener();
+
 	if( s_hasGUI )
 	{
 		s_mainWindow = new mainWindow;

src/core/midi/midi_control_listener.cpp

@@ -0,0 +1,163 @@
+/*
+ * midi_control_listener.cpp - implementation of the MIDI listener that
+ *                             controls LMMS' transportation and other things
+ *
+ * Copyright (c) 2009 Achim Settelmeier <lmms/at/m1.sirlab.de>
+ *
+ * This file is part of Linux MultiMedia Studio - http://lmms.sourceforge.net
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+
+#include "midi_control_listener.h"
+#include "mixer.h"
+#include "midi_client.h"
+#include "midi_port.h"
+#include "engine.h"
+#include "note.h"
+#include "song.h"
+
+
+MidiControlListener::MidiControlListener() :
+	m_port( "unnamed_midi_controller",
+	       engine::getMixer()->getMidiClient(), this, NULL,
+	       midiPort::Input ),
+	m_controlKeyPressed( false )
+{
+	// default settings
+	m_useControlKey = true;   // use control key
+	m_controlKey = 60;        // C5
+	m_controlChannel = -1;    // listen on all channels
+
+#warning TODO replace hard-coded defaults
+	// test config
+	m_port.subscribeReadablePort( "24:0", true );
+	m_actionMapKeys[57] = ActionPlay;
+	m_actionMapKeys[59] = ActionStop;
+	m_actionMapControllers[24] = ActionPlay;
+	m_actionMapControllers[23] = ActionStop;
+}
+
+
+
+
+MidiControlListener::~MidiControlListener()
+{
+}
+
+
+
+
+void MidiControlListener::processInEvent( const midiEvent & _me,
+					 const midiTime & _time )
+{
+	// pre-check whether this MIDI packet suits our configuration
+	switch( _me.m_type )
+	{
+		case MidiNoteOn:
+		case MidiNoteOff:
+		case MidiControlChange:
+			// ignore commands for other channels
+			if( m_controlChannel != -1 &&
+				m_controlChannel != _me.channel() )
+			{
+				return;
+			}
+			break;
+		default:
+			// ignore commands other than note on/off and
+			// control change
+			return;
+	}
+
+	// check MIDI packet type and act upon
+	switch( _me.m_type )
+	{
+		case MidiNoteOn:
+		if( _me.key() == m_controlKey)
+		{
+			if( _me.velocity() == 0 )
+			{
+				// special case: key press with velocity 0
+				// means key release
+				m_controlKeyPressed = false;
+				break;
+			}
+			m_controlKeyPressed = true;
+			break;
+		}
+		else if( !m_useControlKey || m_controlKeyPressed )
+		{
+			if( _me.velocity() > 0 &&
+				m_actionMapKeys.contains( _me.key() ) )
+			{
+				act( m_actionMapKeys.value( _me.key(),
+								ActionNone ) );
+			}
+		}
+		break;
+
+	case MidiNoteOff:
+		if( _me.key() == m_controlKey )
+		{
+			m_controlKeyPressed = false;
+		}
+		break;
+
+	case MidiControlChange:
+		// controller changed to a value other than zero
+		if( _me.m_data.m_param[1] > 0 )
+		{
+			switch( m_actionMapControllers.value(
+					_me.m_data.m_param[0], ActionNone ) )
+			{
+				case ActionNone:
+					break;
+				case ActionPlay:
+					engine::getSong()->play();
+					break;
+				case ActionStop:
+					engine::getSong()->stop();
+					break;
+			}
+		}
+		break;
+	default:
+		// nop
+		break;
+	}
+}
+
+
+
+
+void MidiControlListener::act( EventAction _action )
+{
+	switch( _action )
+	{
+		case ActionNone:
+			break;
+		case ActionPlay:
+			engine::getSong()->play();
+			break;
+		case ActionStop:
+			engine::getSong()->stop();
+			break;
+	}
+}
+