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[3.8.0] MIDI Learn 2 (MIDI 2.0 support)

On this page:

• Introduction
• Example

Related pages:

• [3.0.1] Parameter MIDI Mapping (MIDI 1.0 support)
• [3.6.12] MIDI Learn (MIDI 1.0 support)
• [3.8.0] Parameter MIDI Mapping 2 (MIDI 2.0 support)

Introduction

MIDI Learn Interface: Vst:: IMidiLearn2.

• [plug imp]
• [extends Vst:: IEditController]
• [released: 3.8.0]
• [optional]
• [replaces Vst::IMidiLearn]

If this interface is implemented by the edit controller, the host will call this method whenever there is live MIDI-CC input for the plug-in. This way, the plug-in can change its MIDI-CC parameter mapping and notify the host using the Vst:: IComponentHandler::restartComponent with the kMidiCCAssignmentChanged flag.

Use this if you want to implement custom MIDI-Learn functionality in your plug-in.

Example

In mycontroller.h

//------------------------------------------------------------------------
// here an example of how a VST 3 plug-in could support this IMidiLearn2 interface.
// we need to define somewhere the iids:
  
//in MyController class declaration
class MyController : public Vst::EditController, public Vst::IMidiLearn2
{
    // ...
    //--- IMidiLearn2 ---------------------------------
    tresult PLUGIN_API onLiveMidi2ControllerInput (BusIndex index, MidiChannel channel,
                                                   Midi2Controller midiCC) SMTG_OVERRIDE;
    
	tresult PLUGIN_API onLiveMidi1ControllerInput (BusIndex index, MidiChannel channel,
	                                               CtrlNumber midiCC) SMTG_OVERRIDE;
    // ...
  
    OBJ_METHODS (MyController, Vst::EditController)
    DEFINE_INTERFACES
        // ...
        DEF_INTERFACE (Vst::IMidiLearn2)
    END_DEFINE_INTERFACES (Vst::EditController)
    //...
}

In mycontroller.cpp

#include "pluginterfaces/vst/ivstmidimapping2.h
 
namespace Steinberg {
    namespace Vst {
        DEF_CLASS_IID (IMidiLearn2)
    }
}
  
//------------------------------------------------------------------------
tresult PLUGIN_API  MyController::onLiveMidi2ControllerInput (BusIndex index, MidiChannel channel, Midi2Controller midiCC)
{
    // if we are not in doMIDILearn (triggered by a UI button for example) or wrong channel then return
    if (!doMIDILearn || index != 0 || channel != 0 || midiLearnParamID == InvalidParamID)
        return kResultFalse;
 
    auto currentMapping = midiCCMapping.find ({CCType::CC, midiCC});
    if (currentMapping == midiCCMapping.end () || currentMapping->second != midiLearnParamID)
    {
        removeCurrentMidiLearnParamAssignment ();
        midiCCMapping[{CCType::CC, midiCC}] = midiLearnParamID;
        
        if (auto _componentHandler = getComponentHandler ())
            _componentHandler->restartComponent (kMidiCCAssignmentChanged);
    }
    return kResultTrue;
}

//------------------------------------------------------------------------
tresult PLUGIN_API  MyController::onLiveMidi1ControllerInput (BusIndex index, MidiChannel channel, CtrlNumber midiCC)
{
    // if we are not in doMIDILearn (triggered by a UI button for example) or wrong channel then return
    if (!doMIDILearn || index != 0 || channel != 0 || midiLearnParamID == InvalidParamID)
        return kResultFalse;
 
    CCKey key { midiCC.registered ? CCType::RPN : CCType::NRPN, (midiCC.bank << 7) | midiCC.index };
    auto currentMapping = midiCCMapping.find (key);
    if (currentMapping == midiCCMapping.end () || currentMapping->second != midiLearnParamID)
    {
        removeCurrentMidiLearnParamAssignment ();
        midiCCMapping[key] = midiLearnParamID;

        if (auto _componentHandler = getComponentHandler ())
            _componentHandler->restartComponent (kMidiCCAssignmentChanged);
    }
    return kResultTrue;
}