Revamp synchronization with the audio engine

sakertooth · Sep 21, 2023 · fa3bbbf · fa3bbbf
1 parent 3a0e68c
commit fa3bbbf
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Showing 2 changed files with 36 additions and 66 deletions.
diff --git a/include/AudioEngine.h b/include/AudioEngine.h
@@ -27,6 +27,12 @@
 
 #include <QMutex>
 
+#ifdef __MINGW32__
+#include <mingw.condition_variable.h>
+#else
+#include <condition_variable>
+#endif
+
 #if (QT_VERSION >= QT_VERSION_CHECK(5,14,0))
 	#include <QRecursiveMutex>
 #endif
@@ -475,19 +481,10 @@ class LMMS_EXPORT AudioEngine : public QObject
 
 	bool m_clearSignal;
 
-	bool m_changesSignal;
-	unsigned int m_changes;
-	QMutex m_changesMutex;
-#if (QT_VERSION >= QT_VERSION_CHECK(5,14,0))
-	QRecursiveMutex m_doChangesMutex;
-#else
-	QMutex m_doChangesMutex;
-#endif
-	QMutex m_waitChangesMutex;
-	QWaitCondition m_changesAudioEngineCondition;
-	QWaitCondition m_changesRequestCondition;
-
-	bool m_waitingForWrite;
+	bool m_runChanges;
+	int m_numChanges;
+	std::condition_variable m_numChangesCond, m_runChangesCond;
+	std::mutex m_numChangesMutex, m_runChangesMutex;
 
 	friend class Engine;
 	friend class AudioEngineWorkerThread;

diff --git a/src/core/AudioEngine.cpp b/src/core/AudioEngine.cpp
@@ -90,12 +90,8 @@ AudioEngine::AudioEngine( bool renderOnly ) :
 	m_profiler(),
 	m_metronomeActive(false),
 	m_clearSignal( false ),
-	m_changesSignal( false ),
-	m_changes( 0 ),
-#if (QT_VERSION < QT_VERSION_CHECK(5,14,0))
-	m_doChangesMutex( QMutex::Recursive ),
-#endif
-	m_waitingForWrite( false )
+	m_runChanges(false),
+	m_numChanges(0)
 {
 	for( int i = 0; i < 2; ++i )
 	{
@@ -444,8 +440,6 @@ void AudioEngine::renderStageMix()
 
 	emit nextAudioBuffer(m_outputBufferRead);
 
-	runChangesInModel();
-
 	// and trigger LFOs
 	EnvelopeAndLfoParameters::instances()->trigger();
 	Controller::triggerFrameCounter();
@@ -463,6 +457,7 @@ const surroundSampleFrame *AudioEngine::renderNextBuffer()
 	renderStageInstruments();   // STAGE 1: run and render all play handles
 	renderStageEffects();       // STAGE 2: process effects of all instrument- and sampletracks
 	renderStageMix();           // STAGE 3: do master mix in mixer
+	runChangesInModel();		// STAGE 4: call runChangesInModel to process pending non-automated changes
 
 	s_renderingThread = false;
 	m_profiler.finishPeriod(processingSampleRate(), m_framesPerPeriod);
@@ -805,57 +800,44 @@ void AudioEngine::removePlayHandlesOfTypes(Track * track, PlayHandle::Types type
 
 void AudioEngine::requestChangeInModel()
 {
-	if( s_renderingThread )
-		return;
-
-	m_changesMutex.lock();
-	m_changes++;
-	m_changesMutex.unlock();
+	if (s_renderingThread || !m_isProcessing) { return; }
 
-	m_doChangesMutex.lock();
-	m_waitChangesMutex.lock();
-	if (m_isProcessing && !m_waitingForWrite && !m_changesSignal)
 	{
-		m_changesSignal = true;
-		m_changesRequestCondition.wait( &m_waitChangesMutex );
+		auto lock = std::lock_guard{m_numChangesMutex};
+		++m_numChanges;
 	}
-	m_waitChangesMutex.unlock();
-}
-
-
 
+	auto lock = std::unique_lock{m_runChangesMutex};
+	m_runChangesCond.wait(lock, [this] { return m_runChanges; });
+}
 
 void AudioEngine::doneChangeInModel()
 {
-	if( s_renderingThread )
-		return;
-
-	m_changesMutex.lock();
-	bool moreChanges = --m_changes;
-	m_changesMutex.unlock();
+	if (s_renderingThread || !m_isProcessing) { return; }
 
-	if( !moreChanges )
 	{
-		m_changesSignal = false;
-		m_changesAudioEngineCondition.wakeOne();
+		auto lock = std::lock_guard{m_numChangesMutex};
+		--m_numChanges;
 	}
-	m_doChangesMutex.unlock();
-}
-
-
 
+	m_numChangesCond.notify_one();
+}
 
 void AudioEngine::runChangesInModel()
 {
-	if( m_changesSignal )
 	{
-		m_waitChangesMutex.lock();
-		// allow changes in the model from other threads ...
-		m_changesRequestCondition.wakeOne();
-		// ... and wait until they are done
-		m_changesAudioEngineCondition.wait( &m_waitChangesMutex );
-		m_waitChangesMutex.unlock();
+		auto lock = std::lock_guard{m_runChangesMutex};
+		m_runChanges = true;
+	}
+	m_runChangesCond.notify_all();
+
+	{
+		auto lock = std::unique_lock{m_numChangesMutex};
+		m_numChangesCond.wait(lock, [this] { return m_numChanges == 0; });
 	}
+
+	auto lock = std::lock_guard{m_runChangesMutex};
+	m_runChanges = false;
 }
 
 bool AudioEngine::isAudioDevNameValid(QString name)
@@ -1304,16 +1286,7 @@ void AudioEngine::fifoWriter::run()
 
 void AudioEngine::fifoWriter::write( surroundSampleFrame * buffer )
 {
-	m_audioEngine->m_waitChangesMutex.lock();
-	m_audioEngine->m_waitingForWrite = true;
-	m_audioEngine->m_waitChangesMutex.unlock();
-	m_audioEngine->runChangesInModel();
-
-	m_fifo->write( buffer );
-
-	m_audioEngine->m_doChangesMutex.lock();
-	m_audioEngine->m_waitingForWrite = false;
-	m_audioEngine->m_doChangesMutex.unlock();
+	m_fifo->write(buffer);
 }
 
 } // namespace lmms