Remove some locks from the audio thread (#36)

vberthiaume · Jul 9, 2024 · 8b0e2d3 · 8b0e2d3
1 parent c217297
commit 8b0e2d3
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Showing 4 changed files with 26 additions and 22 deletions.
diff --git a/source/DSP/GainedOscillator.h b/source/DSP/GainedOscillator.h
@@ -43,7 +43,7 @@ class GainedOscillator
         osc.setFrequency (newValue, force);
     }
 
-    void setOscShape (int newShape);
+    void setOscShape (OscShape::Values newShape) { nextOsc.store (newShape); }
 
     /**
      * @brief Sets the gain for the oscillator in the processorChain.
@@ -69,9 +69,7 @@ class GainedOscillator
     template <typename ProcessContext>
     void process (const ProcessContext& context) noexcept
     {
-        //TODO: lock in audio thread!!! This should/could be a try lock and the other one a lock,
-        // so we only lock in the other place. But are these actuallty different threads though?
-        std::lock_guard<std::mutex> lock (processMutex);
+        updateOscillators();
 
         processorChain.process (context);
     }
@@ -85,7 +83,9 @@ class GainedOscillator
         gainIndex
     };
 
-    std::mutex processMutex;
+    std::atomic<OscShape::Values> currentOsc { OscShape::none }, nextOsc { { OscShape::saw } };
+
+    void updateOscillators();
 
     bool isActive = true;
 
@@ -99,23 +99,28 @@ class GainedOscillator
 
 //====================================================================================================
 
-template<std::floating_point T>
-void GainedOscillator<T>::setOscShape (int newShape)
+template <std::floating_point T>
+void GainedOscillator<T>::updateOscillators()
 {
-    auto& osc = processorChain.template get<oscIndex> ();
+    //compare the current osc type with the (buffered next osc type). Get outta here if they the same
+    const auto nextOscBuf { nextOsc.load() };
+    if (currentOsc == nextOscBuf)
+        return;
 
+    //this is to make sure we preserve the same gain after we re-init, right?
     bool wasActive = isActive;
     isActive = true;
 
-    switch (newShape)
+    auto& osc = processorChain.template get<oscIndex>();
+    switch (nextOscBuf)
     {
     case OscShape::none:
+        osc.initialise ([&] (T /*x*/) { return T (0); });
         isActive = false;
         break;
 
     case OscShape::saw:
     {
-        std::lock_guard<std::mutex> lock (processMutex);
         osc.initialise ([](T x)
                         {
                             //this is a sawtooth wave; as x goes from -pi to pi, y goes from -1 to 1
@@ -126,7 +131,6 @@ void GainedOscillator<T>::setOscShape (int newShape)
 
     case OscShape::sawTri:
     {
-        std::lock_guard<std::mutex> lock (processMutex);
         osc.initialise ([](T x)
                         {
                             T y = juce::jmap (x, T (-juce::MathConstants<double>::pi), T (juce::MathConstants<double>::pi), T (-1), T (1)) / 2;
@@ -142,7 +146,6 @@ void GainedOscillator<T>::setOscShape (int newShape)
 
     case OscShape::triangle:
     {
-        std::lock_guard<std::mutex> lock (processMutex);
         osc.initialise ([](T x)
                         {
                             if (x < 0)
@@ -156,7 +159,6 @@ void GainedOscillator<T>::setOscShape (int newShape)
 
     case OscShape::pulse:
     {
-        std::lock_guard<std::mutex> lock (processMutex);
         osc.initialise ([](T x)
                         {
                             if (x < 0)
@@ -169,8 +171,6 @@ void GainedOscillator<T>::setOscShape (int newShape)
 
     case OscShape::noise:
     {
-        std::lock_guard<std::mutex> lock (processMutex);
-
         osc.initialise ([&](T /*x*/)
                         {
                             return distribution (generator);
@@ -190,4 +190,6 @@ void GainedOscillator<T>::setOscShape (int newShape)
         else
             setGain (0);
     }
+
+    currentOsc.store (nextOscBuf);
 }
diff --git a/source/DSP/PhatOscillators.h b/source/DSP/PhatOscillators.h
@@ -68,7 +68,7 @@ class PhatOscillators : public juce::AudioProcessorValueTreeState::Listener
     }
 
     void setOscFreq (OscId oscNum, int newMidiNote);
-    void setOscShape (OscId oscNum, int newShape);
+    void setOscShape (OscId oscNum, OscShape::Values newShape);
     void setOscTuning (OscId oscNum, float newTuning);
 
     void setOscSub (float newSub)
@@ -203,9 +203,9 @@ void PhatOscillators<T>::parameterChanged (const juce::String& parameterID, floa
     else if (parameterID == osc2TuningID.getParamID ())
         setOscTuning (OscId::osc2Index, newValue);
     else if (parameterID == osc1ShapeID.getParamID ())
-        setOscShape (OscId::osc1Index, (int) newValue);
+        setOscShape (OscId::osc1Index, static_cast<OscShape::Values> (newValue));
     else if (parameterID == osc2ShapeID.getParamID ())
-        setOscShape (OscId::osc2Index, (int) newValue);
+        setOscShape (OscId::osc2Index, static_cast<OscShape::Values> (newValue));
     else if (parameterID == oscSubID.getParamID ())
         setOscSub (newValue);
     else if (parameterID == oscMixID.getParamID ())
@@ -318,7 +318,7 @@ void PhatOscillators<T>::setOscFreq (OscId oscNum, int newMidiNote)
 }
 
 template <std::floating_point T>
-void PhatOscillators<T>::setOscShape (OscId oscNum, int newShape)
+void PhatOscillators<T>::setOscShape (OscId oscNum, OscShape::Values newShape)
 {
     switch (oscNum)
     {

diff --git a/source/DSP/ProPhatVoice.h b/source/DSP/ProPhatVoice.h
@@ -496,8 +496,10 @@ void ProPhatVoice<T>::updateLfo()
 {
     T lfoOut;
     {
-        //TODO: LOCK IN AUDIO THREAD
-        std::lock_guard<std::mutex> lock (lfoMutex);
+        std::unique_lock<std::mutex> lck (lfoMutex, std::defer_lock);
+        if (! lck.try_lock())
+            return;
+
         lfoOut = lfo.processSample (T (0)) * lfoAmount;
     }
 

diff --git a/source/Utility/Helpers.h b/source/Utility/Helpers.h
@@ -218,7 +218,7 @@ struct Selection
 
 struct OscShape : public Selection
 {
-    enum
+    enum Values
     {
         none = 0,
         saw,