Stop buttons MIDI control.

Author: Archie3d

README.md

@@ -23,13 +23,23 @@ The rest and the most of the code (including voicing, spatialisation, reverb, et
 The convolution reverb uses impulse responses 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).
-> In a DAW use `Program` parameter to control the sequencer steps.
-
-Control MIDI channel:
-- `CC 1` modulation wheel enables/disables tremulant;
-- `CC 7` controls the global volume and the volume of each division which has `swell` enabled;
-- `CC 91` controls the reverb output level;
+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).
+> In a DAW you may use `Program` parameter to control the sequencer steps.
+
+MIDI controllers (CCs):
+- `CC 1` modulation wheel enables/disables tremulant
+- `CC 7` controls the global volume (on the control MIDI channel) and the volume of each division which has `swell` config flag enabled (on the swell MIDI channel)
+- `CC 91` controls the reverb output level
+- `CC 98` Stops control
+
+> :point_right: The stops control follows the original Aeolus convention. The control mode is set by the message `01mm0ggg`, where `mm` is the control mode, and `ggg` is the control group (division number, counter from the top starting from `0`).
+> Control modes are:
+> - `00` Disable the division (all stops are off)
+> - `01` Set stop off
+> - `10` Set stop on
+> - `11` Toggle
+>
+> Once the control message is received the value of the format `000bbbbb` will execute the selected control mode action on specified stop buton `bbbbb`, counted from `0`.
 
 ## Custom organ configuration
 Custom organ configuration will be loaded by the plugin if found at `Documents/Aeolus/organ_config.json` location.

Source/aeolus/engine.cpp

@@ -863,9 +863,9 @@ void Engine::applyVolume(float* outL, float* outR, int numFrames)
 
 void Engine::processControlMIDIMessage(const MidiMessage& message)
 {
-    // NOTE: VST3 will not pass the program change MIDI messages through.
-    // Instead program change must be handled at the processor level
-    // via the setCurrentProgram() method.
+    // @note VST3 will not pass the program change MIDI messages through.
+    //       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.
@@ -874,6 +874,71 @@ void Engine::processControlMIDIMessage(const MidiMessage& message)
 
         if (step >= 0 && step < _sequencer->getStepsCount())
             _sequencer->setStep(step);
+    } else if (message.isController() && message.getControllerNumber() == CC_STOP_BUTTONS) {
+        const auto value{ message.getControllerValue() };
+
+        if (value & 0xC8 == 0x40) {
+            // 01mm0ggg
+            StopControlMode mode { StopControlMode::Disabled };
+
+            const int modeValue{ (value >> 4) & 0x03 >> 4 };
+            switch (modeValue) {
+                case 0: mode = StopControlMode::Disabled; break;
+                case 1: mode = StopControlMode::SetOff; break;
+                case 2: mode = StopControlMode::SetOn; break;
+                case 3: mode = StopControlMode::Toggle; break;
+                default: break;
+            }
+
+            _stopControlMode = mode;
+            _stopControlGroup = value & 0x07;
+
+            if (_stopControlMode == StopControlMode::Disabled) {
+                // Disable message does not require a 2nd part and can be processed immeditely.
+                processStopControlMessage();
+
+                _stopControlMode.reset();
+            }
+        } else if (value & 0xE0 == 0) {
+            // 000bbbbb
+            if (_stopControlMode.has_value()) {
+                _stopControlButton = value & 0x1F;
+
+                processStopControlMessage();
+            }
+        } else {
+            _stopControlMode.reset();
+        }
+    }
+}
+
+void Engine::processStopControlMessage()
+{
+    if (!_stopControlMode.has_value())
+        return;
+
+    if (!juce::isPositiveAndBelow(_stopControlGroup, _divisions.size()))
+        return;
+
+    auto* division{ _divisions.getUnchecked(_stopControlGroup) };
+
+    const auto mode{ *_stopControlMode };
+
+    switch (mode) {
+        case StopControlMode::Disabled:
+            division->disableAllStops();
+            break;
+        case StopControlMode::SetOff:
+            division->enableStop(_stopControlButton, false);
+            break;
+        case StopControlMode::SetOn:
+            division->enableStop(_stopControlButton, true);
+            break;
+        case StopControlMode::Toggle:
+            division->enableStop(_stopControlButton, !division->isStopEnabled(_stopControlButton));
+            break;
+        default:
+            break;
     }
 }
 

Source/aeolus/engine.h

@@ -32,6 +32,7 @@
 #include "aeolus/dsp/convolver.h"
 #include "aeolus/dsp/interpolator.h"
 
+#include <optional>
 #include <vector>
 
 AEOLUS_NAMESPACE_BEGIN
@@ -304,8 +305,12 @@ class Engine
     void applyVolume(juce::AudioBuffer<float>& out);
     void applyVolume(float* outL, float* outR, int numFrames);
 
+    /// Process control MIDI messages: program change (sequencer) and stop buttons CC.
     void processControlMIDIMessage(const juce::MidiMessage& message);
 
+    /// Process stop buttons MIDI controls.
+    void processStopControlMessage();
+
     float _sampleRate;
 
     RingBuffer<NoteEvent, 1024> _pendingNoteEvents;
@@ -314,6 +319,10 @@ class Engine
 
     AudioParameterPool _params;     ///< Internal parameters.
 
+    std::optional<StopControlMode> _stopControlMode{};
+    int _stopControlGroup{};
+    int _stopControlButton{};
+
     /// List of all divisions
     juce::OwnedArray<Division> _divisions;
 

Source/aeolus/globals.h

@@ -103,7 +103,15 @@ constexpr static float TUNING_FREQUENCY_DEFAULT = 440.0f;
 enum {
     CC_MODULATION = 1,
     CC_VOLUME = 7,
-    CC_REVERB = 91
+    CC_REVERB = 91,
+    CC_STOP_BUTTONS = 98
+};
+
+enum class StopControlMode {
+    Disabled,   // 0b00
+    SetOff,     // 0b01
+    SetOn,      // 0b10
+    Toggle      // 0b11
 };
 
 //==============================================================================