Add MIDI Modulator processor

CHANGELOG.md

@@ -8,6 +8,7 @@ All notable changes to this project will be documented in this file.
 - Added "Crying Child" module.
 - Added "Solo-Vibe" module.
 - Added "Ladder Filter" module.
+- Added "MIDI Modulator" module.
 - Added "netlist view" to allow for customization of some circuit-modelled modules.
 - Added AVX support (for PCs that support it) for neural network-based modules.
 - Added mouse interactions for selecting and moving/deleting multiple modules at once.

CMakeLists.txt

@@ -85,6 +85,7 @@ juce_add_plugin(BYOD
     FORMATS ${JUCE_FORMATS}
     ProductName "BYOD"
     ICON_BIG res/logo.png
+    NEEDS_MIDI_INPUT True
 
     VST2_CATEGORY kPlugCategEffect
     VST3_CATEGORIES Fx Distortion

src/BYOD.cpp

@@ -46,16 +46,17 @@ void BYOD::prepareToPlay (double sampleRate, int samplesPerBlock)
     bypassScratchBuffer.setSize (2, samplesPerBlock);
 }
 
-void BYOD::processAudioBlock (AudioBuffer<float>& buffer)
+void BYOD::processBlock (AudioBuffer<float>& buffer, MidiBuffer& midi)
 {
+    const juce::ScopedNoDenormals noDenormals {};
     AudioProcessLoadMeasurer::ScopedTimer loadTimer { loadMeasurer, buffer.getNumSamples() };
 
     // push samples into bypass delay
     bypassScratchBuffer.makeCopyOf (buffer, true);
     processBypassDelay (bypassScratchBuffer);
 
     // real processing here!
-    procs->processAudio (buffer);
+    procs->processAudio (buffer, midi);
 
     chowdsp::BufferMath::sanitizeBuffer<AudioBuffer<float>, float> (buffer);
 }

src/BYOD.h

@@ -15,7 +15,9 @@ class BYOD : public chowdsp::PluginBase<BYOD>
     static void addParameters (Parameters& params);
     void prepareToPlay (double sampleRate, int samplesPerBlock) override;
     void releaseResources() override {}
-    void processAudioBlock (AudioBuffer<float>& buffer) override;
+    bool acceptsMidi() const override { return true; }
+    void processAudioBlock (AudioBuffer<float>&) override {}
+    void processBlock (AudioBuffer<float>& buffer, MidiBuffer& midiMessages) override;
     void processBlockBypassed (AudioBuffer<float>& buffer, MidiBuffer& midiMessages) override;
 
     AudioProcessorEditor* createEditor() override;

src/CMakeLists.txt

@@ -118,6 +118,7 @@ target_sources(BYOD PRIVATE
     processors/modulation/Rotary.cpp
     processors/modulation/Tremolo.cpp
     processors/modulation/Flanger.cpp
+    processors/modulation/MIDIModulator.cpp
     processors/modulation/phaser/Phaser4.cpp
     processors/modulation/phaser/Phaser8.cpp
     processors/modulation/scanner_vibrato/ScannerVibrato.cpp

src/headless/tests/PreBufferTest.cpp

@@ -41,8 +41,10 @@ class PreBufferTest : public UnitTest
             {
                 proc->prepareProcessing (testSampleRate, testBlockSize);
 
+                MidiBuffer midi;
                 AudioBuffer<float> buffer (1, testBlockSize);
                 buffer.clear();
+                proc->midiBuffer = &midi;
                 proc->processAudioBlock (buffer);
 
                 const auto steadyStateMax = [] (const auto& name)

src/headless/tests/StereoTest.cpp

@@ -44,13 +44,14 @@ class StereoTest : public UnitTest
         plugin.getVTS().getParameter ("mono_mode")->setValueNotifyingHost (0.0f);
         MessageManager::getInstance()->runDispatchLoopUntil (100);
 
+        MidiBuffer midi;
         AudioBuffer<float> buffer (2, blockSize);
         buffer.clear();
-        chain.processAudio (buffer);
+        chain.processAudio (buffer, midi);
 
         FloatVectorOperations::fill (buffer.getWritePointer (0), 1.0f, blockSize);
         FloatVectorOperations::fill (buffer.getWritePointer (1), 1.0f, blockSize);
-        chain.processAudio (buffer);
+        chain.processAudio (buffer, midi);
 
         auto leftMinMax = FloatVectorOperations::findMinAndMax (buffer.getReadPointer (0) + blockSize / 2, blockSize / 2);
         auto rightMinMax = FloatVectorOperations::findMinAndMax (buffer.getReadPointer (1) + blockSize / 2, blockSize / 2);
@@ -99,13 +100,14 @@ class StereoTest : public UnitTest
         plugin.getVTS().getParameter ("mono_mode")->setValueNotifyingHost (0.35f);
         MessageManager::getInstance()->runDispatchLoopUntil (100);
 
+        MidiBuffer midi;
         AudioBuffer<float> buffer (2, blockSize);
         buffer.clear();
-        chain.processAudio (buffer);
+        chain.processAudio (buffer, midi);
 
         FloatVectorOperations::fill (buffer.getWritePointer (0), 1.0f, blockSize);
         FloatVectorOperations::fill (buffer.getWritePointer (1), -1.0f, blockSize);
-        chain.processAudio (buffer);
+        chain.processAudio (buffer, midi);
 
         auto leftMinMax = FloatVectorOperations::findMinAndMax (buffer.getReadPointer (0) + blockSize / 2, blockSize / 2);
         auto rightMinMax = FloatVectorOperations::findMinAndMax (buffer.getReadPointer (1) + blockSize / 2, blockSize / 2);
@@ -138,13 +140,14 @@ class StereoTest : public UnitTest
         plugin.getVTS().getParameter ("mono_mode")->setValueNotifyingHost (0.35f);
         MessageManager::getInstance()->runDispatchLoopUntil (100);
 
+        MidiBuffer midi;
         AudioBuffer<float> buffer (2, blockSize);
         buffer.clear();
-        chain.processAudio (buffer);
+        chain.processAudio (buffer, midi);
 
         FloatVectorOperations::fill (buffer.getWritePointer (0), 1.0f, blockSize);
         FloatVectorOperations::fill (buffer.getWritePointer (1), -1.0f, blockSize);
-        chain.processAudio (buffer);
+        chain.processAudio (buffer, midi);
 
         auto leftMinMax = FloatVectorOperations::findMinAndMax (buffer.getReadPointer (0) + blockSize / 2, blockSize / 2);
         auto rightMinMax = FloatVectorOperations::findMinAndMax (buffer.getReadPointer (1) + blockSize / 2, blockSize / 2);
@@ -177,13 +180,14 @@ class StereoTest : public UnitTest
         plugin.getVTS().getParameter ("mono_mode")->setValueNotifyingHost (0.35f);
         MessageManager::getInstance()->runDispatchLoopUntil (100);
 
+        MidiBuffer midi;
         AudioBuffer<float> buffer (2, blockSize);
         buffer.clear();
-        chain.processAudio (buffer);
+        chain.processAudio (buffer, midi);
 
         FloatVectorOperations::fill (buffer.getWritePointer (0), 1.0f, blockSize);
         FloatVectorOperations::fill (buffer.getWritePointer (1), -1.0f, blockSize);
-        chain.processAudio (buffer);
+        chain.processAudio (buffer, midi);
 
         auto leftMinMax = FloatVectorOperations::findMinAndMax (buffer.getReadPointer (0) + blockSize / 2, blockSize / 2);
         auto rightMinMax = FloatVectorOperations::findMinAndMax (buffer.getReadPointer (1) + blockSize / 2, blockSize / 2);

src/processors/BaseProcessor.h

@@ -186,9 +186,15 @@ class BaseProcessor : private JuceProcWrapper
     const auto& getParameters() const { return AudioProcessor::getParameters(); }
 
     bool isOutputModulationPortConnected();
-
     const std::vector<String>* getParametersToDisableWhenInputIsConnected (int portIndex) const noexcept;
 
+    /**
+     * MIDI buffer that the processor may access during processAudio() or processAudioBypassed().
+     * While in those methods, the processor chain will ensure that the MIDI buffer is non-null.
+     * At all other times this will be null.
+     */
+    const MidiBuffer* midiBuffer = nullptr;
+
 protected:
     virtual void prepare (double sampleRate, int samplesPerBlock) = 0;
     virtual void releaseMemory() {}

src/processors/ProcessorStore.cpp

@@ -39,6 +39,7 @@
 
 #include "modulation/Chorus.h"
 #include "modulation/Flanger.h"
+#include "modulation/MIDIModulator.h"
 #include "modulation/Panner.h"
 #include "modulation/Rotary.h"
 #include "modulation/Tremolo.h"
@@ -118,6 +119,7 @@ ProcessorStore::StoreMap ProcessorStore::store = {
 
     { "Chorus", &processorFactory<Chorus> },
     { "Flanger", &processorFactory<Flanger> },
+    { "MIDI Modulator", &processorFactory<MidiModulator> },
     { "Panner", &processorFactory<Panner> },
     { "Phaser4", &processorFactory<Phaser4> },
     { "Phaser8", &processorFactory<Phaser8> },

src/processors/chain/ProcessorChain.cpp

@@ -16,6 +16,18 @@ namespace
         std::cout << "Level for channel: " << ch << ": " << level << std::endl;
     }
 }
+
+const MidiBuffer& getMidiBufferToUse (const MidiBuffer& hostMidiBuffer, MidiBuffer& internalMidiBuffer, int osFactor)
+{
+    if (hostMidiBuffer.isEmpty() || osFactor == 1)
+        return hostMidiBuffer;
+
+    internalMidiBuffer.clear();
+    for (const auto& midiEvent : hostMidiBuffer)
+        internalMidiBuffer.addEvent (midiEvent.getMessage(), midiEvent.samplePosition * osFactor);
+
+    return internalMidiBuffer;
+}
 } // namespace
 
 ProcessorChain::ProcessorChain (ProcessorStore& store,
@@ -70,6 +82,9 @@ void ProcessorChain::prepare (double sampleRate, int samplesPerBlock)
 
     ioProcessor.prepare (sampleRate, samplesPerBlock);
 
+    internalMidiBuffer.clear();
+    internalMidiBuffer.ensureSize (256);
+
     SpinLock::ScopedLockType scopedProcessingLock (processingLock);
     initializeProcessors();
 }
@@ -151,7 +166,7 @@ void ProcessorChain::runProcessor (BaseProcessor* proc, AudioBuffer<float>& buff
     }
 }
 
-void ProcessorChain::processAudio (AudioBuffer<float>& buffer)
+void ProcessorChain::processAudio (AudioBuffer<float>& buffer, const MidiBuffer& hostMidiBuffer)
 {
     SpinLock::ScopedTryLockType tryProcessingLock (processingLock);
     if (! tryProcessingLock.isLocked())
@@ -178,10 +193,15 @@ void ProcessorChain::processAudio (AudioBuffer<float>& buffer)
             inputBuffer.copyFrom (ch, 0, osBlock.getChannelPointer ((size_t) ch), osNumSamples);
     }
 
-    // process standalone modulation ports
     bool outProcessed = false;
+    const auto& processMidiBuffer = getMidiBufferToUse (hostMidiBuffer, internalMidiBuffer, ioProcessor.getOversamplingFactor());
+
     for (auto* processor : procs)
     {
+        // set up MIDI buffer
+        processor->midiBuffer = &processMidiBuffer;
+
+        // process standalone modulation ports
         auto noInputsConnected = processor->getNumInputConnections() == 0;
         auto modOutputConnected = processor->isOutputModulationPortConnected();
         if (noInputsConnected && modOutputConnected)
@@ -192,7 +212,10 @@ void ProcessorChain::processAudio (AudioBuffer<float>& buffer)
     runProcessor (&inputProcessor, inputBuffer, outProcessed);
 
     for (auto* processor : procs)
+    {
+        processor->midiBuffer = nullptr;
         processor->clearNumInputsReady();
+    }
 
     if (! outProcessed)
     {

src/processors/chain/ProcessorChain.h

@@ -22,7 +22,7 @@ class ProcessorChain : private AudioProcessorValueTreeState::Listener
 
     static void createParameters (Parameters& params);
     void prepare (double sampleRate, int samplesPerBlock);
-    void processAudio (AudioBuffer<float>& buffer);
+    void processAudio (AudioBuffer<float>& buffer, const MidiBuffer& hostMidiBuffer);
 
     auto& getProcessors() { return procs; }
     const auto& getProcessors() const { return procs; }
@@ -77,5 +77,7 @@ class ProcessorChain : private AudioProcessorValueTreeState::Listener
     chowdsp::DeferredAction mainThreadAction;
     std::unique_ptr<ParamForwardManager>& paramForwardManager;
 
+    MidiBuffer internalMidiBuffer;
+
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ProcessorChain)
 };