AudioProcessor: Add VST2/VST3 midi note name support

Co-authored-by: Roland Rabien <roland@rabien.com>

modules/juce_audio_plugin_client/juce_audio_plugin_client_VST2.cpp

@@ -918,6 +918,7 @@ public:
             case Vst2::effSetProcessPrecision:      return handleSetSampleFloatType (args);
             case Vst2::effGetNumMidiInputChannels:  return handleGetNumMidiInputChannels();
             case Vst2::effGetNumMidiOutputChannels: return handleGetNumMidiOutputChannels();
+            case Vst2::effGetMidiKeyName:           return handleGetMidiKeyName (args);
             case Vst2::effEditIdle:                 return handleEditIdle();
             default:                                return 0;
         }
@@ -2049,6 +2050,22 @@ private:
         return 0;
     }
 
+    pointer_sized_int handleGetMidiKeyName (VstOpCodeArguments args)
+    {
+        if (processor != nullptr)
+        {
+            auto keyName = (Vst2::MidiKeyName*) args.ptr;
+
+            if (auto name = processor->getNameForMidiNoteNumber (keyName->thisKeyNumber, args.index))
+            {
+                name->copyToUTF8 (keyName->keyName, Vst2::kVstMaxNameLen);
+                return 1;
+            }
+        }
+
+        return 0;
+    }
+
     pointer_sized_int handleEditIdle()
     {
        #if JUCE_LINUX || JUCE_BSD

modules/juce_audio_plugin_client/juce_audio_plugin_client_VST3.cpp

@@ -525,9 +525,27 @@ public:
         return kResultFalse;
     }
 
+    tresult PLUGIN_API hasProgramPitchNames (Vst::ProgramListID, Steinberg::int32) override
+    {
+        for (int i = 0; i <= 127; ++i)
+            if (audioProcessor->getNameForMidiNoteNumber (i, 1))
+                return kResultTrue;
+
+        return kResultFalse;
+    }
+
+    tresult PLUGIN_API getProgramPitchName (Vst::ProgramListID, Steinberg::int32, Steinberg::int16 midiNote, Vst::String128 nameOut) override
+    {
+        if (auto name = audioProcessor->getNameForMidiNoteNumber (midiNote, 1))
+        {
+            toString128 (nameOut, *name);
+            return kResultTrue;
+        }
+
+        return kResultFalse;
+    }
+
     tresult PLUGIN_API getProgramInfo (Vst::ProgramListID, Steinberg::int32, Vst::CString, Vst::String128) override             { return kNotImplemented; }
-    tresult PLUGIN_API hasProgramPitchNames (Vst::ProgramListID, Steinberg::int32) override                                     { return kNotImplemented; }
-    tresult PLUGIN_API getProgramPitchName (Vst::ProgramListID, Steinberg::int32, Steinberg::int16, Vst::String128) override    { return kNotImplemented; }
     tresult PLUGIN_API selectUnit (Vst::UnitID) override                                                                        { return kNotImplemented; }
     tresult PLUGIN_API setUnitProgramData (Steinberg::int32, Steinberg::int32, IBStream*) override                              { return kNotImplemented; }
     Vst::UnitID PLUGIN_API getSelectedUnit() override                                                                           { return Vst::kRootUnitId; }

modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp

@@ -3090,6 +3090,22 @@ public:
         return result;
     }
 
+    std::optional<String> getNameForMidiNoteNumber (int note, int /*midiChannel*/) override
+    {
+        if (unitInfo == nullptr || unitInfo->getProgramListCount() == 0)
+            return std::nullopt;
+
+        Vst::String128 name{};
+        Vst::ProgramListInfo programListInfo{};
+
+        const auto nameOk = unitInfo->getProgramListInfo (0, programListInfo)      == kResultOk
+                         && unitInfo->hasProgramPitchNames (programListInfo.id, 0) == kResultTrue
+                         && unitInfo->getProgramPitchName (programListInfo.id, 0, (Steinberg::int16) note, name) == kResultOk;
+
+        return nameOk ? std::make_optional (toString (name))
+                      : std::nullopt;
+    }
+
     //==============================================================================
     void updateTrackProperties (const TrackProperties& properties) override
     {

modules/juce_audio_processors/format_types/juce_VSTPluginFormat.cpp

@@ -1335,6 +1335,18 @@ struct VSTPluginInstance final   : public AudioPluginInstance,
 
     int pluginCanDo (const char* text) const  { return (int) dispatch (Vst2::effCanDo, 0, 0, (void*) text,  0); }
 
+    std::optional<String> getNameForMidiNoteNumber (int note, int midiChannel) override
+    {
+        Vst2::MidiKeyName keyName{};
+
+        keyName.thisProgramIndex = getCurrentProgram();
+        keyName.thisKeyNumber = note;
+
+        return dispatch (Vst2::effGetMidiKeyName, midiChannel, 0, &keyName, 0.0f) != 0
+             ? std::make_optional (String::createStringFromData (keyName.keyName, Vst2::kVstMaxNameLen))
+             : std::nullopt;
+    }
+
     //==============================================================================
     void prepareToPlay (double rate, int samplesPerBlockExpected) override
     {

modules/juce_audio_processors/processors/juce_AudioProcessor.cpp

@@ -950,6 +950,11 @@ void AudioProcessor::copyXmlToBinary (const XmlElement& xml, juce::MemoryBlock&
         = ByteOrder::swapIfBigEndian ((uint32) destData.getSize() - 9);
 }
 
+std::optional<String> AudioProcessor::getNameForMidiNoteNumber (int /*note*/, int /*midiChannel*/)
+{
+    return std::nullopt;
+}
+
 std::unique_ptr<XmlElement> AudioProcessor::getXmlFromBinary (const void* data, const int sizeInBytes)
 {
     if (sizeInBytes > 8 && ByteOrder::littleEndianInt (data) == magicXmlNumber)

modules/juce_audio_processors/processors/juce_AudioProcessor.h

@@ -1327,6 +1327,21 @@ public:
     */
     virtual void updateTrackProperties (const TrackProperties& properties);
 
+    /** Returns a custom name for a MIDI note number.
+
+        This method allows the host to query your plugin for a custom name to display
+        for a given MIDI note number. It's useful for plugins that work with drum kits,
+        microtonal scales, or other mappings.
+
+        @param note         The MIDI note number for which the name is being requested.
+                            This is an integer in the range [0, 127], representing the
+                            full MIDI note range.
+        @param midiChannel  The MIDI channel associated with the note. This is a 1-based
+                            index (1-16). Use this parameter if your plugin provides
+                            channel-specific note mappings.
+    */
+    virtual std::optional<String> getNameForMidiNoteNumber (int note, int midiChannel);
+
     //==============================================================================
     /** Helper function that just converts an xml element into a binary blob.