demonstrate that Mixxx does not need to handle vsync itself

src/waveform/visualplayposition.cpp

@@ -59,7 +59,7 @@ double VisualPlayPosition::getAtNextVSync(VSyncThread* vSyncThread) {
     if (m_valid) {
         VisualPlayPositionData data = m_data.getValue();
         int refToVSync = vSyncThread->fromTimerToNextSyncMicros(data.m_referenceTime);
-        int offset = refToVSync - data.m_callbackEntrytoDac;
+        int offset = data.m_callbackEntrytoDac;
         offset = math_min(offset, m_audioBufferMicros * kMaxOffsetBufferCnt);
         double playPos = data.m_enginePlayPos;  // load playPos for the first sample in Buffer
         // add the offset for the position of the sample that will be transferred to the DAC
@@ -78,11 +78,9 @@ void VisualPlayPosition::getPlaySlipAtNextVSync(VSyncThread* vSyncThread, double
 
     if (m_valid) {
         VisualPlayPositionData data = m_data.getValue();
-        int refToVSync = vSyncThread->fromTimerToNextSyncMicros(data.m_referenceTime);
-        int offset = refToVSync - data.m_callbackEntrytoDac;
-        offset = math_min(offset, m_audioBufferMicros * kMaxOffsetBufferCnt);
         double playPos = data.m_enginePlayPos;  // load playPos for the first sample in Buffer
-        playPos += data.m_positionStep * offset * data.m_rate / m_audioBufferMicros;
+        playPos += data.m_positionStep * data.m_callbackEntrytoDac *
+                data.m_rate / m_audioBufferMicros;
         *pPlayPosition = playPos;
         *pSlipPosition = data.m_slipPosition;
     }

src/waveform/vsyncthread.cpp

@@ -55,33 +55,9 @@ void VSyncThread::run() {
         } else { // if (m_vSyncMode == ST_TIMER) {
             emit vsyncRender(); // renders the new waveform.
 
-            // wait until rendering was scheduled. It might be delayed due a
-            // pending swap (depends one driver vSync settings)
             m_semaVsyncSlot.acquire();
 
-            // qDebug() << "ST_TIMER                      " << lastMicros << restMicros;
-            int remainingForSwap = m_waitToSwapMicros - static_cast<int>(
-                m_timer.elapsed().toIntegerMicros());
-            // waiting for interval by sleep
-            if (remainingForSwap > 100) {
-                usleep(remainingForSwap);
-            }
-
-            // swaps the new waveform to front in case of gl-wf
-            emit vsyncSwap();
-
-            // wait until swap occurred. It might be delayed due to driver vSync
-            // settings.
-            m_semaVsyncSlot.acquire();
-
-            // <- Assume we are VSynced here ->
             int lastSwapTime = static_cast<int>(m_timer.restart().toIntegerMicros());
-            if (remainingForSwap < 0) {
-                // Our swapping call was already delayed
-                // The real swap might happens on the following VSync, depending on driver settings
-                m_droppedFrames++; // Count as Real Time Error
-            }
-            // try to stay in right intervals
             m_waitToSwapMicros = m_syncIntervalTimeMicros +
                     ((m_waitToSwapMicros - lastSwapTime) % m_syncIntervalTimeMicros);
         }

src/waveform/waveformwidgetfactory.cpp

@@ -721,7 +721,7 @@ void WaveformWidgetFactory::swap() {
                     if (glw->context() != QGLContext::currentContext()) {
                         glw->makeCurrent();
                     }
-                    glw->swapBuffers();
+                    //glw->swapBuffers();
                 }
                 //qDebug() << "swap x" << m_vsyncThread->elapsed();
             }

src/waveform/widgets/glsimplewaveformwidget.cpp

@@ -34,8 +34,6 @@ GLSimpleWaveformWidget::GLSimpleWaveformWidget(const QString& group, QWidget* pa
     setAttribute(Qt::WA_NoSystemBackground);
     setAttribute(Qt::WA_OpaquePaintEvent);
 
-    setAutoBufferSwap(false);
-
     m_initSuccess = init();
 }
 

src/waveform/widgets/glslwaveformwidget.cpp

@@ -66,8 +66,6 @@ GLSLWaveformWidget::GLSLWaveformWidget(
     setAttribute(Qt::WA_NoSystemBackground);
     setAttribute(Qt::WA_OpaquePaintEvent);
 
-    setAutoBufferSwap(false);
-
     m_initSuccess = init();
 }
 

src/waveform/widgets/glvsynctestwidget.cpp

@@ -36,8 +36,6 @@ GLVSyncTestWidget::GLVSyncTestWidget(const QString& group, QWidget* parent)
     setAttribute(Qt::WA_NoSystemBackground);
     setAttribute(Qt::WA_OpaquePaintEvent);
 
-    setAutoBufferSwap(false);
-
     m_initSuccess = init();
     qDebug() << "GLVSyncTestWidget.isSharing() =" << isSharing();
 }

src/waveform/widgets/glwaveformwidget.cpp

@@ -36,8 +36,6 @@ GLWaveformWidget::GLWaveformWidget(const QString& group, QWidget* parent)
     setAttribute(Qt::WA_NoSystemBackground);
     setAttribute(Qt::WA_OpaquePaintEvent);
 
-    setAutoBufferSwap(false);
-
     m_initSuccess = init();
 }