Combine frames and scratch_rate into one optional because they are al…

…ways valid.

src/effects/backends/builtin/autopaneffect.cpp

@@ -88,10 +88,10 @@ void AutoPanEffect::processChannel(
     double period = m_pPeriodParameter->value();
     const auto smoothing = static_cast<float>(0.5 - m_pSmoothingParameter->value());
 
-    if (groupFeatures.beat_length_frames.has_value()) {
+    if (groupFeatures.beat_length.has_value()) {
         // period is a number of beats
         double beats = std::max(roundToFraction(period, 2), 0.25);
-        period = beats * *groupFeatures.beat_length_frames;
+        period = beats * groupFeatures.beat_length->frames;
 
         // TODO(xxx) sync phase
         //if (groupFeatures.has_beat_fraction) {

src/effects/backends/builtin/echoeffect.cpp

@@ -132,7 +132,7 @@ void EchoEffect::processChannel(
     const auto pingpong_frac = static_cast<CSAMPLE_GAIN>(m_pPingPongParameter->value());
 
     int delay_frames;
-    if (groupFeatures.beat_length_frames.has_value()) {
+    if (groupFeatures.beat_length.has_value()) {
         // period is a number of beats
         if (m_pQuantizeParameter->toBool()) {
             period = std::max(roundToFraction(period, 4), 1 / 8.0);
@@ -142,7 +142,7 @@ void EchoEffect::processChannel(
         } else if (period < 1 / 8.0) {
             period = 1 / 8.0;
         }
-        delay_frames = static_cast<int>(period * *groupFeatures.beat_length_frames);
+        delay_frames = static_cast<int>(period * groupFeatures.beat_length->frames);
     } else {
         // period is a number of seconds
         period = std::max(period, 1 / 8.0);

src/effects/backends/builtin/flangereffect.cpp

@@ -117,13 +117,13 @@ void FlangerEffect::processChannel(
         const GroupFeatureState& groupFeatures) {
     double lfoPeriodParameter = m_pSpeedParameter->value();
     double lfoPeriodFrames;
-    if (groupFeatures.beat_length_frames.has_value()) {
+    if (groupFeatures.beat_length.has_value()) {
         // lfoPeriodParameter is a number of beats
         lfoPeriodParameter = std::max(roundToFraction(lfoPeriodParameter, 2.0), kMinLfoBeats);
         if (m_pTripletParameter->toBool()) {
             lfoPeriodParameter /= 3.0;
         }
-        lfoPeriodFrames = lfoPeriodParameter * *groupFeatures.beat_length_frames;
+        lfoPeriodFrames = lfoPeriodParameter * groupFeatures.beat_length->frames;
     } else {
         // lfoPeriodParameter is a number of seconds
         lfoPeriodFrames = std::max(lfoPeriodParameter, kMinLfoBeats) *

src/effects/backends/builtin/metronomeeffect.cpp

@@ -94,18 +94,11 @@ void MetronomeEffect::processChannel(
     double bufferEnd = gs->m_framesSinceClickStart + engineParameters.framesPerBuffer();
 
     double nextClickStart = bufferEnd; // default to "no new click";
-    if (m_pSyncParameter->toBool() && groupFeatures.beat_length_frames.has_value()) {
-        if (groupFeatures.beat_fraction_buffer_end.has_value()) {
-            double beatLength = *groupFeatures.beat_length_frames;
-            if (groupFeatures.scratch_rate.has_value()) {
-                if (*groupFeatures.scratch_rate != 0.0) {
-                    beatLength /= *groupFeatures.scratch_rate;
-                } else {
-                    // no transport, nothing to do.
-                    return;
-                }
-            }
-
+    if (m_pSyncParameter->toBool() && groupFeatures.beat_fraction_buffer_end.has_value()) {
+        // Sync enabled and have a track with beats
+        if (groupFeatures.beat_length.has_value() && groupFeatures.beat_length->scratch_rate) {
+            double beatLength = groupFeatures.beat_length->frames /
+                    groupFeatures.beat_length->scratch_rate;
             double beatToBufferEnd;
             if (beatLength > 0) {
                 beatToBufferEnd =
@@ -122,7 +115,8 @@ void MetronomeEffect::processChannel(
                 nextClickStart = bufferEnd - beatToBufferEnd;
             }
         } else {
-            nextClickStart = *groupFeatures.beat_length_frames;
+            // no transport, nothing to do.
+            return;
         }
     } else {
         nextClickStart = engineParameters.sampleRate() * 60 / m_pBpmParameter->value();

src/effects/backends/builtin/phasereffect.cpp

@@ -132,13 +132,13 @@ void PhaserEffect::processChannel(
 
     double periodParameter = m_pLFOPeriodParameter->value();
     double periodSamples;
-    if (groupFeatures.beat_length_frames.has_value()) {
+    if (groupFeatures.beat_length.has_value()) {
         // periodParameter is a number of beats
         periodParameter = std::max(roundToFraction(periodParameter, 2.0), 1 / 4.0);
         if (m_pTripletParameter->toBool()) {
             periodParameter /= 3.0;
         }
-        periodSamples = periodParameter * *groupFeatures.beat_length_frames;
+        periodSamples = periodParameter * groupFeatures.beat_length->frames;
     } else {
         // periodParameter is a number of seconds
         periodSamples = std::max(periodParameter, 1 / 4.0) * engineParameters.sampleRate();

src/effects/backends/builtin/tremoloeffect.cpp

@@ -138,9 +138,9 @@ void TremoloEffect::processChannel(
     bool tripletDisabling = pState->tripletEnabled && !m_pTripletParameter->toBool();
 
     if (enableState == EffectEnableState::Enabling || quantizeEnabling || tripletDisabling) {
-        if (gf.beat_length_frames.has_value() && gf.beat_fraction_buffer_end.has_value()) {
+        if (gf.beat_length.has_value() && gf.beat_fraction_buffer_end.has_value()) {
             currentFrame = static_cast<unsigned int>(*gf.beat_fraction_buffer_end *
-                    *gf.beat_length_frames);
+                    gf.beat_length->frames);
         } else {
             currentFrame = 0;
         }
@@ -149,7 +149,7 @@ void TremoloEffect::processChannel(
 
     int framePerPeriod;
     double rate = m_pRateParameter->value();
-    if (gf.beat_length_frames.has_value() && gf.beat_fraction_buffer_end.has_value()) {
+    if (gf.beat_length.has_value() && gf.beat_fraction_buffer_end.has_value()) {
         if (m_pQuantizeParameter->toBool()) {
             const auto divider = static_cast<int>(log2(rate));
             rate = pow(2, divider);
@@ -158,7 +158,7 @@ void TremoloEffect::processChannel(
                 rate *= 3.0;
             }
         }
-        const auto framePerBeat = static_cast<int>(*gf.beat_length_frames);
+        const auto framePerBeat = static_cast<int>(gf.beat_length->frames);
         framePerPeriod = static_cast<int>(framePerBeat / rate);
     } else {
         framePerPeriod = static_cast<int>(engineParameters.sampleRate() / rate);

src/engine/controls/bpmcontrol.cpp

@@ -1108,8 +1108,7 @@ void BpmControl::collectFeatures(GroupFeatureState* pGroupFeatures, double speed
                 &beatFraction)) {
         const double rateRatio = m_pRateRatio->get();
         if (rateRatio != 0.0) {
-            pGroupFeatures->beat_length_frames = beatLengthFrames / rateRatio;
-            pGroupFeatures->scratch_rate = speed / rateRatio;
+            pGroupFeatures->beat_length = {beatLengthFrames / rateRatio, speed / rateRatio};
         }
         pGroupFeatures->beat_fraction_buffer_end = beatFraction;
     }

src/engine/effects/groupfeaturestate.h

@@ -2,16 +2,19 @@
 
 #include <optional>
 
+struct GroupFeatureBeatLength {
+    // Beat length adjusted by the rate slider
+    double frames;
+    // Rate change by temporary actions like scratching
+    // and not the rate slider.
+    double scratch_rate;
+};
+
 /// GroupFeatureState communicates metadata about EngineChannels to EffectProcessors.
 struct GroupFeatureState {
     GroupFeatureState() = default;
 
-    // Adjusted by the rate slider
-    std::optional<double> beat_length_frames;
-
-    // Rate change by temporary actions like scratching
-    // and not the rate slider.
-    std::optional<double> scratch_rate;
+    std::optional<GroupFeatureBeatLength> beat_length;
 
     // Beat fraction (0.0 to 1.0) of the position at the buffer end.
     // Previous beat is in the current or earlier buffer. The next beat