fix sync delay

Source/DelayEngine.h

@@ -231,6 +231,13 @@ public:
         }
     }
 
+    static float syncTimeMs (int index, double bpm)
+    {
+        const int idx = std::clamp (index, 0, numDivisions - 1);
+        const double secondsPerBeat = 60.0 / std::max (1.0, bpm);
+        return static_cast<float> (divisionBeats[static_cast<std::size_t> (idx)] * secondsPerBeat * 1000.0);
+    }
+
 private:
     static float softClip (float x)
     {

Source/PluginEditor.cpp

@@ -57,6 +57,22 @@ public:
         panKnob.setValueTextFunction ([] (double v) { return juce::String (juce::roundToInt (v * 100.0)) + "%"; });
         onToggle.setInverted (true);
 
+        syncToggle.onClick = [this]
+        {
+            if (syncToggle.getToggleState())
+                return;
+
+            const int index = juce::roundToInt (proc.apvts.getRawParameterValue (ParameterIDs::timeSync)->load());
+            const float ms = mindball::DelayEngine::syncTimeMs (index, proc.getCurrentBpm());
+
+            if (auto* timeParam = proc.apvts.getParameter (ParameterIDs::time))
+            {
+                timeParam->beginChangeGesture();
+                timeParam->setValueNotifyingHost (timeParam->convertTo0to1 (juce::roundToInt (ms)));
+                timeParam->endChangeGesture();
+            }
+        };
+
         buildInfo.setJustificationType (juce::Justification::centredRight);
         buildInfo.setFont (juce::Font (juce::Font::getDefaultMonospacedFontName(), 9.0f, 0));
 

Source/PluginProcessor.cpp

@@ -84,6 +84,11 @@ bool MindballAudioProcessor::isBusesLayoutSupported (const BusesLayout& layouts)
         && (mainIn == juce::AudioChannelSet::mono() || mainIn == juce::AudioChannelSet::stereo());
 }
 
+double MindballAudioProcessor::getCurrentBpm() const
+{
+    return lastBpm.load (std::memory_order_relaxed);
+}
+
 void MindballAudioProcessor::processBlock (juce::AudioBuffer<float>& buffer, juce::MidiBuffer&)
 {
     juce::ScopedNoDenormals noDenormals;
@@ -109,13 +114,14 @@ void MindballAudioProcessor::processBlock (juce::AudioBuffer<float>& buffer, juc
     }
     wasBypassed = false;
 
-    double bpm = 120.0;
+    double bpm = lastBpm.load (std::memory_order_relaxed);
     if (auto* playHead = getPlayHead())
     {
         juce::AudioPlayHead::CurrentPositionInfo pos;
-        if (playHead->getCurrentPosition (pos))
+        if (playHead->getCurrentPosition (pos) && pos.bpm > 0)
-            bpm = pos.bpm > 0 ? pos.bpm : 120.0;
+            bpm = pos.bpm;
     }
+    lastBpm.store (bpm, std::memory_order_relaxed);
 
     mindball::DelayEngine::Params p;
     p.feedback  = *apvts.getRawParameterValue (ParameterIDs::feedback);

Source/PluginProcessor.h

@@ -53,6 +53,8 @@ public:
     void getStateInformation (juce::MemoryBlock& destData) override;
     void setStateInformation (const void* data, int sizeInBytes) override;
 
+    double getCurrentBpm() const;
+
     float getDryMeterL() const { return dryMeterL.load (std::memory_order_relaxed); }
     float getDryMeterR() const { return dryMeterR.load (std::memory_order_relaxed); }
     float getWetMeterL() const { return wetMeterL.load (std::memory_order_relaxed); }
@@ -70,6 +72,7 @@ private:
     float meterDryL = 0.0f, meterDryR = 0.0f;
     float meterWetL = 0.0f, meterWetR = 0.0f;
     float meterDecay = 0.0f;
+    std::atomic<double> lastBpm { 120.0 };
     std::atomic<float> dryMeterL { 0.0f }, dryMeterR { 0.0f };
     std::atomic<float> wetMeterL { 0.0f }, wetMeterR { 0.0f };
 };