Sequencer MIDI control.

Author: Archie3d

README.md

@@ -20,3 +20,6 @@ From the original implementation this project takes only `addsynth` and `rankwav
 The rest and the most of the code (including voicing, spatialisation, reverb, etc.) is all new, and it is not based on the original Aeolus, so the sound this plugin produces is different.
 
 The convolution reverb uses IRs from the [Open AIR](https://www.openair.hosted.york.ac.uk/) project database.
+
+## MIDI Control
+Sequencer steps are controlled via the program change messages sent on the control MIDI channel (program 0 corresponds to the first step of the sequencer, 1 - to the second and so on).

Source/PluginEditor.cpp

@@ -48,6 +48,8 @@ AeolusAudioProcessorEditor::AeolusAudioProcessorEditor (AeolusAudioProcessor& p)
     , _volumeLevelR{p.getEngine().getVolumeLevel().right, ui::LevelIndicator::Orientation::Horizontal}
     , _panicButton{"PANIC"}
     , _cancelButton{"Cancel"}
+    , _midiControlChannelLabel{{}, {"Conrol channel"}}
+    , _midiControlChannelComboBox{}
 {
     setLookAndFeel(&ui::CustomLookAndFeel::getInstance());
 
@@ -132,6 +134,21 @@ AeolusAudioProcessorEditor::AeolusAudioProcessorEditor (AeolusAudioProcessor& p)
 
     addAndMakeVisible(_sequencerView);
 
+    _midiControlChannelLabel.setColour(Label::textColourId, Colour(0x99, 0x99, 0x99));
+    addAndMakeVisible(_midiControlChannelLabel);
+
+    _midiControlChannelComboBox.addItem("All", 1);
+    for (int i = 1; i <= 16; ++i) {
+        _midiControlChannelComboBox.addItem(String(i), i + 1);
+    }
+
+    _midiControlChannelComboBox.setSelectedId(1 + _audioProcessor.getEngine().getMIDIControlChannel(), juce::dontSendNotification);
+    _midiControlChannelComboBox.onChange = [this]() {
+        _audioProcessor.getEngine().setMIDIControlChannel(_midiControlChannelComboBox.getSelectedId() - 1);
+    };
+
+    addAndMakeVisible(_midiControlChannelComboBox);
+
     resized();
 
     startTimerHz(10);
@@ -196,6 +213,10 @@ void AeolusAudioProcessorEditor::resized()
 
     _cancelButton.setColour(TextButton::buttonColourId, Colour(0x66, 0x66, 0x33));
     _cancelButton.setBounds((_midiKeyboard.getX() - 60)/2, getHeight() - 60, 60, 35);
+
+    int x = _midiKeyboard.getRight() + (getWidth() - _midiKeyboard.getRight() - 100) / 2;
+    _midiControlChannelLabel.setBounds(x, _midiKeyboard.getY(), 100, 20);
+    _midiControlChannelComboBox.setBounds(x, _midiControlChannelLabel.getBottom() + 5, 100, 20);
 }
 
 void AeolusAudioProcessorEditor::timerCallback()
@@ -218,7 +239,9 @@ void AeolusAudioProcessorEditor::refresh()
 {
     updateMeters();
     updateDivisionViews();
+    updateSequencerView();
     updateMidiKeyboardRange();
+    updateMidiControlChannel();
 }
 
 void AeolusAudioProcessorEditor::updateMeters()
@@ -245,3 +268,14 @@ void AeolusAudioProcessorEditor::updateDivisionViews()
     for (auto* dv : _divisionViews)
         dv->update();
 }
+
+void AeolusAudioProcessorEditor::updateSequencerView()
+{
+    _sequencerView.update();
+}
+
+void AeolusAudioProcessorEditor::updateMidiControlChannel()
+{
+    const int ch = _audioProcessor.getEngine().getMIDIControlChannel();
+    _midiControlChannelComboBox.setSelectedId(1 + ch, juce::dontSendNotification);
+}

Source/PluginEditor.h

@@ -54,6 +54,8 @@ class AeolusAudioProcessorEditor  : public juce::AudioProcessorEditor,
     void updateMeters();
     void updateMidiKeyboardRange();
     void updateDivisionViews();
+    void updateSequencerView();
+    void updateMidiControlChannel();
 
     AeolusAudioProcessor& _audioProcessor;
 
@@ -85,5 +87,9 @@ class AeolusAudioProcessorEditor  : public juce::AudioProcessorEditor,
     /// Organ cancel button
     juce::TextButton _cancelButton;
 
+    /// MIDI control channel selection
+    juce::Label _midiControlChannelLabel;
+    juce::ComboBox _midiControlChannelComboBox;
+
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (AeolusAudioProcessorEditor)
 };

Source/PluginProcessor.cpp

@@ -78,27 +78,30 @@ bool AeolusAudioProcessor::isMidiEffect() const
 
 double AeolusAudioProcessor::getTailLengthSeconds() const
 {
-    return 0.0;
+    return _engine.getReverbLengthInSeconds();
 }
 
 int AeolusAudioProcessor::getNumPrograms()
 {
-    return 1;   // NB: some hosts don't cope very well if you tell them there are 0 programs,
-                // so this should be at least 1, even if you're not really implementing programs.
+    // NB: some hosts don't cope very well if you tell them there are 0 programs,
+    // so this should be at least 1, even if you're not really implementing programs.
+    return jmax(1, _engine.getSequencer()->getStepsCount());
 }
 
 int AeolusAudioProcessor::getCurrentProgram()
 {
-    return 0;
+    return _engine.getSequencer()->getCurrentStep();
 }
 
-void AeolusAudioProcessor::setCurrentProgram (int /* index */)
+void AeolusAudioProcessor::setCurrentProgram (int index)
 {
+    if (index >= 0 && index < _engine.getSequencer()->getStepsCount())
+        _engine.getSequencer()->setStep(index);
 }
 
-const juce::String AeolusAudioProcessor::getProgramName (int /* index */)
+const juce::String AeolusAudioProcessor::getProgramName (int index)
 {
-    return {};
+    return juce::String("Sequencer step ") + juce::String(index + 1);
 }
 
 void AeolusAudioProcessor::changeProgramName (int /* index */, const juce::String& /* newName */)
@@ -196,7 +199,7 @@ void AeolusAudioProcessor::processMidi (juce::MidiBuffer& midiMessages)
     for (auto msgIter : midiMessages) {
         const auto msg = msgIter.getMessage();
 
-        _engine.getMidiKeyboardState().processNextMidiEvent(msg);
+        _engine.processMIDIMessage(msg);
     }
 
 }

Source/aeolus/engine.cpp

@@ -204,6 +204,7 @@ Engine::Engine()
     , _interpolator{1.0f}
     , _midiKeyboardState{}
     , _volumeLevel{}
+    , _midiControlChannel{0}
 {
     populateDivisions();
 
@@ -254,6 +255,11 @@ void Engine::postReverbIR(int num)
     _irSwitchEvents.send({num});
 }
 
+float Engine::getReverbLengthInSeconds() const
+{
+    return float(_convolver.length()) * SAMPLE_RATE_R;
+}
+
 void Engine::setReverbWet(float v)
 {
     _convolver.setDryWet(1.0f, v);
@@ -328,6 +334,17 @@ void Engine::process(float* outL, float* outR, int numFrames, bool isNonRealtime
     _volumeLevel.right.process(origOutR, origNumFrames);
 }
 
+void Engine::processMIDIMessage(const MidiMessage& message)
+{
+    const int ch = getMIDIControlChannel();
+
+    if (ch == 0 || message.getChannel() == 0 || message.getChannel() == getMIDIControlChannel())
+        processControlMIDIMessage(message);
+    
+    if (message.isNoteOnOrOff())
+        _midiKeyboardState.processNextMidiEvent(message);
+}
+
 void Engine::noteOn(int note, int midiChannel)
 {
     clearDivisionsTriggerFlag();
@@ -388,6 +405,9 @@ var Engine::getPersistentState() const
 {
     auto* obj = new DynamicObject();
 
+    // Save control channel
+    obj->setProperty("midi_ctrl_channel", getMIDIControlChannel());
+
     // Save the IR.
     int irNum = _selectedIR;
     obj->setProperty("ir", irNum);
@@ -410,6 +430,9 @@ var Engine::getPersistentState() const
 void Engine::setPersistentState(const var& state)
 {
     if (const auto* obj = state.getDynamicObject()) {
+        // Restore control channel
+        setMIDIControlChannel(obj->getProperty("midi_ctrl_channel"));
+
         // Restore the IR
         int irNum = obj->getProperty("ir");
 
@@ -580,4 +603,20 @@ void Engine::applyVolume(float* outL, float* outR, int numFrames)
     }
 }
 
+void Engine::processControlMIDIMessage(const MidiMessage& message)
+{
+    // NOTE: VST3 will not pass through the program change MIDI messages.
+    // Instead program change must be handled at the processor level
+    // via the setCurrentProgram() method.
+
+    // Here we handle the program change message nevertheless
+    // in case of a non-VST3 or stand-alone plugin.
+    if (message.isProgramChange()) {
+        int step = message.getProgramChangeNumber();
+
+        if (step >= 0 && step < _sequencer->getStepsCount())
+            _sequencer->setStep(step);
+    }
+}
+
 AEOLUS_NAMESPACE_END

Source/aeolus/engine.h

@@ -161,6 +161,8 @@ class Engine
      */
     int getReverbIR() const noexcept { return _selectedIR; }
 
+    float getReverbLengthInSeconds() const;
+
     /**
      * Set reverb wet output level (linear).
      * @note This must be called on the audio thread.
@@ -178,11 +180,26 @@ class Engine
      */
     Level& getVolumeLevel() noexcept { return _volumeLevel; }
 
+    /**
+     * Assign MIDI channel to be used to control the organ stops and sequencer.
+     */
+    int getMIDIControlChannel() const noexcept { return _midiControlChannel; }
+
+    /**
+     * Returns currently set MIDI control channel.
+     */
+    void setMIDIControlChannel(int c) noexcept { _midiControlChannel = c; }
+
     /**
      * Generate audio.
      */
     void process(float* outL, float* outR, int numFrames, bool isNonRealtime = false);
 
+    /**
+     * Process incoming MIDI messages.
+     */
+    void processMIDIMessage(const juce::MidiMessage& message);
+
     /**
      * Handle note-on events.
      */
@@ -233,6 +250,8 @@ class Engine
     /// Apply the gloval volume.
     void applyVolume(float* outL, float* outR, int numFrames);
 
+    void processControlMIDIMessage(const juce::MidiMessage& message);
+
     float _sampleRate;
 
     RingBuffer<NoteEvent, 1024> _pendingNoteEvents;
@@ -266,6 +285,8 @@ class Engine
 
     Level _volumeLevel;
 
+    std::atomic<int> _midiControlChannel;
+
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(Engine)
 };
 

Source/aeolus/sequencer.cpp

@@ -90,7 +90,6 @@ Sequencer::Sequencer(Engine& engine, int numSteps)
     : _engine{engine}
     , _steps(numSteps)
     , _currentStep{0}
-    , _listeners{}
 {
     jassert(_steps.size() > 0);
 
@@ -107,7 +106,7 @@ var Sequencer::getPersistentState() const
         stepsArr.add(_steps[stepIdx].getPersistentState());
 
     sequencerObj->setProperty("steps", stepsArr);
-    sequencerObj->setProperty("current_step", _currentStep);
+    sequencerObj->setProperty("current_step", getCurrentStep());
 
     return var{sequencerObj};
 }
@@ -148,10 +147,6 @@ void Sequencer::setStep(int index, bool captureCurrentState)
 
         _currentStep = index;
         recallState(_steps[_currentStep]);
-
-        _listeners.call([index](Listener& listener) {
-                listener.sequencerStepChanged(index);
-            });
     }
 }
 

Source/aeolus/sequencer.h

@@ -20,7 +20,7 @@
 #pragma once
 
 #include "aeolus/globals.h"
-
+#include <atomic>
 #include <vector>
 
 AEOLUS_NAMESPACE_BEGIN
@@ -51,22 +51,12 @@ class Sequencer
         void setPersistentState(const juce::var& v);
     };
 
-    class Listener
-    {
-    public:
-        virtual ~Listener() {};
-        virtual void sequencerStepChanged(int step) = 0;
-    };
-
     Sequencer() = delete;
     Sequencer(Engine& engine, int numSteps);
 
     int getStepsCount() const noexcept { return (int)_steps.size(); }
     int getCurrentStep() const noexcept { return _currentStep; }
 
-    void addListener(Listener* listener) { _listeners.add(listener); }
-    void removeListener(Listener* listener) { _listeners.remove(listener); }
-
     juce::var getPersistentState() const;
     void setPersistentState(const juce::var& v);
 
@@ -87,9 +77,7 @@ class Sequencer
 
     Engine& _engine;
     std::vector<OrganState> _steps;
-    int _currentStep;
-
-    juce::ListenerList<Listener> _listeners;
+    std::atomic<int> _currentStep;
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(Sequencer)
 };

Source/ui/DivisionControlPanel.cpp

@@ -46,7 +46,7 @@ DivisionControlPanel::DivisionControlPanel(aeolus::Division* division)
         _midiChannelComboBox.addItem(String(i), i + 1);
     }
 
-    _midiChannelComboBox.setSelectedId(1 + _division->getMIDIChannel(), true);
+    _midiChannelComboBox.setSelectedId(1 + _division->getMIDIChannel(), juce::dontSendNotification);
     _midiChannelComboBox.onChange = [this]() {
         _division->setMIDIChannel(_midiChannelComboBox.getSelectedId() - 1);
     };

Source/ui/SequencerView.cpp

@@ -37,13 +37,14 @@ SequencerView::SequencerView(aeolus::Sequencer* sequencer)
             _sequencer->stepForward();
         };
     addAndMakeVisible(_advanceButton);
-
-    _sequencer->addListener(this);
 }
 
-SequencerView::~SequencerView()
+void SequencerView::update()
 {
-    _sequencer->removeListener(this);
+    const auto currentStep = _sequencer->getCurrentStep();
+
+    for (int i = 0; i < _stepButtons.size(); ++i)
+        _stepButtons[i]->setToggleState(i == currentStep, juce::dontSendNotification);
 }
 
 void SequencerView::resized()
@@ -69,12 +70,6 @@ void SequencerView::resized()
     _advanceButton.setBounds(x, buttonPadding, 2 * buttonWidth, getHeight() - 2 * buttonPadding);
 }
 
-void SequencerView::sequencerStepChanged(int step)
-{
-    if (step >= 0 && step < _stepButtons.size())
-        _stepButtons[step]->setToggleState(true, juce::dontSendNotification);
-}
-
 void SequencerView::populateStepButtons()
 {
     const auto numSteps = _sequencer->getStepsCount();