initial support for parallel rendering via worker-threads - far from being perfect (especially with small mixer-period-sizes) but seems to help even on a DualCore machine

git-svn-id: https://lmms.svn.sf.net/svnroot/lmms/branches/lmms-mv@720 0778d3d1-df1d-0410-868b-ea421aaaa00d

include/mixer.h

@@ -31,6 +31,7 @@
 #endif
 
 #include <QtCore/QMutex>
+#include <QtCore/QSemaphore>
 #include <QtCore/QThread>
 #include <QtCore/QVector>
 
@@ -91,6 +92,8 @@ const tones BASE_TONE = A;
 const octaves BASE_OCTAVE = OCTAVE_4;
 
 
+class mixerWorkerThread;
+
 
 class mixer : public QObject
 {
@@ -361,7 +364,10 @@ private:
 	bool m_newBuffer[SURROUND_CHANNELS];
 	
 	Uint8 m_cpuLoad;
-	int m_parallelizingLevel;
+	bool m_multiThreaded;
+	QVector<mixerWorkerThread *> m_workers;
+	QSemaphore m_workerSem;
+
 
 	playHandleVector m_playHandles;
 	constPlayHandleVector m_playHandlesToRemove;
@@ -389,6 +395,7 @@ private:
 
 
 	friend class engine;
+	friend class mixerWorkerThread;
 
 } ;