Adapt the processing to mono/stereo

src/sfizz/EQPool.cpp

@@ -8,7 +8,7 @@ using namespace std::chrono_literals;
 sfz::EQHolder::EQHolder(const MidiState& state)
 :midiState(state)
 {
-    eq.setChannels(2);
+
 }
 
 void sfz::EQHolder::reset()
@@ -16,9 +16,10 @@ void sfz::EQHolder::reset()
     eq.clear();
 }
 
-void sfz::EQHolder::setup(const EQDescription& description, uint8_t velocity)
+void sfz::EQHolder::setup(const EQDescription& description, unsigned numChannels, uint8_t velocity)
 {
     reset();
+    eq.setChannels(numChannels);
     this->description = &description;
     const auto normalizedVelocity = normalizeVelocity(velocity);
 
@@ -80,7 +81,7 @@ sfz::EQPool::EQPool(const MidiState& state, int numEQs)
     setnumEQs(numEQs);
 }
 
-sfz::EQHolderPtr sfz::EQPool::getEQ(const EQDescription& description, uint8_t velocity)
+sfz::EQHolderPtr sfz::EQPool::getEQ(const EQDescription& description, unsigned numChannels, uint8_t velocity)
 {
     AtomicGuard guard { givingOutEQs };
     if (!canGiveOutEQs)
@@ -93,7 +94,7 @@ sfz::EQHolderPtr sfz::EQPool::getEQ(const EQDescription& description, uint8_t ve
     if (eq == eqs.end())
         return {};
 
-    (**eq).setup(description, velocity);
+    (**eq).setup(description, numChannels, velocity);
     return *eq;
 }
 

src/sfizz/EQPool.h

@@ -17,8 +17,10 @@ public:
      * @brief Setup a new EQ based on an EQ description.
      *
      * @param description the EQ description
+     * @param numChannels the number of channels for the EQ
+     * @param description the triggering velocity/value
      */
-    void setup(const EQDescription& description, uint8_t velocity);
+    void setup(const EQDescription& description, unsigned numChannels, uint8_t velocity);
     /**
      * @brief Process a block of stereo inputs
      *
@@ -84,11 +86,11 @@ public:
      * @brief Get an EQ object to use in Voices
      *
      * @param description the filter description to bind to the EQ
-     * @param noteNumber the triggering note number
+     * @param numChannels the number of channels for the EQ
-     * @param velocity the triggering note velocity
+     * @param velocity the triggering note velocity/value
      * @return EQHolderPtr release this when done with the filter; no deallocation will be done
      */
-    EQHolderPtr getEQ(const EQDescription& description, uint8_t velocity);
+    EQHolderPtr getEQ(const EQDescription& description, unsigned numChannels, uint8_t velocity);
     /**
      * @brief Get the number of active EQs
      *

src/sfizz/FilterPool.cpp

@@ -9,7 +9,7 @@ using namespace std::chrono_literals;
 sfz::FilterHolder::FilterHolder(const MidiState& midiState)
 : midiState(midiState)
 {
-    filter.setChannels(2);
+
 }
 
 void sfz::FilterHolder::reset()
@@ -17,11 +17,12 @@ void sfz::FilterHolder::reset()
     filter.clear();
 }
 
-void sfz::FilterHolder::setup(const FilterDescription& description, int noteNumber, uint8_t velocity)
+void sfz::FilterHolder::setup(const FilterDescription& description, unsigned numChannels, int noteNumber, uint8_t velocity)
 {
     reset();
     this->description = &description;
     filter.setType(description.type);
+    filter.setChannels(numChannels);
 
     baseCutoff = description.cutoff;
     if (description.random != 0) {
@@ -88,7 +89,7 @@ sfz::FilterPool::FilterPool(const MidiState& state, int numFilters)
     setNumFilters(numFilters);
 }
 
-sfz::FilterHolderPtr sfz::FilterPool::getFilter(const FilterDescription& description, int noteNumber, uint8_t velocity)
+sfz::FilterHolderPtr sfz::FilterPool::getFilter(const FilterDescription& description, unsigned numChannels, int noteNumber, uint8_t velocity)
 {
     AtomicGuard guard { givingOutFilters };
     if (!canGiveOutFilters)
@@ -101,7 +102,7 @@ sfz::FilterHolderPtr sfz::FilterPool::getFilter(const FilterDescription& descrip
     if (filter == filters.end())
         return {};
 
-    (**filter).setup(description, noteNumber, velocity);
+    (**filter).setup(description, numChannels, noteNumber, velocity);
     return *filter;
 }
 

src/sfizz/FilterPool.h

@@ -17,10 +17,11 @@ public:
      * @brief Setup a new filter based on a filter description, and a triggering note parameters.
      *
      * @param description the filter description
+     * @param numChannels the number of channels
      * @param noteNumber the triggering note number
-     * @param velocity the triggering note velocity
+     * @param velocity the triggering note velocity/value
      */
-    void setup(const FilterDescription& description, int noteNumber = static_cast<int>(Default::filterKeycenter), uint8_t velocity = 0);
+    void setup(const FilterDescription& description, unsigned numChannels, int noteNumber = static_cast<int>(Default::filterKeycenter), uint8_t velocity = 0);
     /**
      * @brief Process a block of stereo inputs
      *
@@ -88,11 +89,12 @@ public:
      * @brief Get a filter object to use in Voices
      *
      * @param description the filter description to bind to the filter
+     * @param numChannels the number of channels in the underlying filter
      * @param noteNumber the triggering note number
      * @param velocity the triggering note velocity
      * @return FilterHolderPtr release this when done with the filter; no deallocation will be done
      */
-    FilterHolderPtr getFilter(const FilterDescription& description, int noteNumber = static_cast<int>(Default::filterKeycenter), uint8_t velocity = 0);
+    FilterHolderPtr getFilter(const FilterDescription& description, unsigned numChannels, int noteNumber = static_cast<int>(Default::filterKeycenter), uint8_t velocity = 0);
     /**
      * @brief Get the number of active filters
      *

src/sfizz/Voice.cpp

@@ -91,14 +91,15 @@ void sfz::Voice::startVoice(Region* region, int delay, int number, uint8_t value
     ASSERT((filters.capacity() - filters.size()) >= region->filters.size());
     ASSERT((equalizers.capacity() - equalizers.size()) >= region->equalizers.size());
 
+    const unsigned numChannels = region->isStereo ? 2 : 1;
     for (auto& filter: region->filters) {
-        auto newFilter = resources.filterPool.getFilter(filter, number, value);
+        auto newFilter = resources.filterPool.getFilter(filter, numChannels, number, value);
         if (newFilter)
             filters.push_back(newFilter);
     }
 
     for (auto& eq: region->equalizers) {
-        auto newEQ = resources.eqPool.getEQ(eq, value);
+        auto newEQ = resources.eqPool.getEQ(eq, numChannels, value);
         if (newEQ)
             equalizers.push_back(newEQ);
     }
@@ -276,17 +277,6 @@ void sfz::Voice::renderBlock(AudioSpan<float> buffer) noexcept
     else
         processMono(buffer);
 
-    const float* inputChannels[2] { buffer.getChannel(0), buffer.getChannel(1) };
-    float* outputChannels[2] { buffer.getChannel(0), buffer.getChannel(1) };
-
-    for (auto& filter: filters) {
-        filter->process(inputChannels, outputChannels, buffer.getNumFrames());
-    }
-
-    for (auto& eq: equalizers) {
-        eq->process(inputChannels, outputChannels, buffer.getNumFrames());
-    }
-
     if (!egEnvelope.isSmoothing())
         reset();
 
@@ -319,6 +309,17 @@ void sfz::Voice::processMono(AudioSpan<float> buffer) noexcept
     egEnvelope.getBlock(span1);
     applyGain<float>(span1, leftBuffer);
 
+    // Filtering and EQ
+    const float* inputChannel[1] { leftBuffer.data() };
+    float* outputChannel[1] { leftBuffer.data() };
+    for (auto& filter: filters) {
+        filter->process(inputChannel, outputChannel, numSamples);
+    }
+
+    for (auto& eq: equalizers) {
+        eq->process(inputChannel, outputChannel, numSamples);
+    }
+
     // Prepare for stereo output
     copy<float>(leftBuffer, rightBuffer);
 
@@ -390,6 +391,18 @@ void sfz::Voice::processStereo(AudioSpan<float> buffer) noexcept
     multiplyAdd<float>(span2, span3, rightBuffer);
     applyGain<float>(sqrtTwoInv<float>, leftBuffer);
     applyGain<float>(sqrtTwoInv<float>, rightBuffer);
+
+    // Filtering and EQ
+    const float* inputChannels[2] { leftBuffer.data(), rightBuffer.data() };
+    float* outputChannels[2] { leftBuffer.data(), rightBuffer.data() };
+
+    for (auto& filter: filters) {
+        filter->process(inputChannels, outputChannels, numSamples);
+    }
+
+    for (auto& eq: equalizers) {
+        eq->process(inputChannels, outputChannels, numSamples);
+    }
 }
 
 void sfz::Voice::fillWithData(AudioSpan<float> buffer) noexcept