Implement MIDI sending to VST from UI

vst/SfizzVstEditor.cpp

@@ -176,10 +176,20 @@ void SfizzVstEditor::uiEndSend(EditId id)
         getController()->endEdit(pid);
 }
 
-void SfizzVstEditor::uiSendMIDI(const uint8_t* msg, uint32_t len)
+void SfizzVstEditor::uiSendMIDI(const uint8_t* data, uint32_t len)
 {
-    // TODO send MIDI...
-    
+    SfizzVstController* ctl = getController();
+
+    Steinberg::OPtr<Vst::IMessage> msg { ctl->allocateMessage() };
+    if (!msg) {
+        fprintf(stderr, "[Sfizz] UI could not allocate message\n");
+        return;
+    }
+
+    msg->setMessageID("MidiMessage");
+    Vst::IAttributeList* attr = msg->getAttributes();
+    attr->setBinary("Data", data, len);
+    ctl->sendMessage(msg);
 }
 
 ///

vst/SfizzVstEditor.h

@@ -40,7 +40,7 @@ protected:
     void uiSendValue(EditId id, const EditValue& v) override;
     void uiBeginSend(EditId id) override;
     void uiEndSend(EditId id) override;
-    void uiSendMIDI(const uint8_t* msg, uint32_t len) override;
+    void uiSendMIDI(const uint8_t* data, uint32_t len) override;
 
 private:
     void loadSfzFile(const std::string& filePath);

vst/SfizzVstProcessor.cpp

@@ -22,8 +22,10 @@ static const char defaultSfzText[] =
     "<region>sample=*sine" "\n"
     "ampeg_attack=0.02 ampeg_release=0.1" "\n";
 
+enum { kMidiEventMaximumSize = 4 };
+
 SfizzVstProcessor::SfizzVstProcessor()
-    : _fifoToWorker(64 * 1024)
+    : _fifoToWorker(64 * 1024), _fifoMidiFromUi(64 * 1024)
 {
     setControllerClass(SfizzVstController::cid);
 }
@@ -181,6 +183,8 @@ tresult PLUGIN_API SfizzVstProcessor::process(Vst::ProcessData& data)
     else
         synth.disableFreeWheeling();
 
+    processMidiFromUi();
+
     if (Vst::IParameterChanges* pc = data.inputParameterChanges)
         processControllerChanges(*pc);
 
@@ -373,6 +377,40 @@ void SfizzVstProcessor::processEvents(Vst::IEventList& events)
     }
 }
 
+void SfizzVstProcessor::processMidiFromUi()
+{
+    sfz::Sfizz& synth = *_synth;
+
+    for (uint32 size = 0; _fifoMidiFromUi.peek(size) &&
+             _fifoMidiFromUi.size_used() >= sizeof(size) + size; ) {
+        _fifoMidiFromUi.discard(sizeof(size));
+
+        if (size > kMidiEventMaximumSize) {
+            _fifoMidiFromUi.discard(size);
+            continue;
+        }
+
+        uint8_t data[kMidiEventMaximumSize] = {};
+        _fifoMidiFromUi.get(data, size);
+
+        // interpret the MIDI message
+        switch (data[0] & 0xf0) {
+        case 0x80:
+            synth.noteOff(0, data[1] & 0x7f, data[2] & 0x7f);
+            break;
+        case 0x90:
+            synth.noteOn(0, data[1] & 0x7f, data[2] & 0x7f);
+            break;
+        case 0xb0:
+            synth.cc(0, data[1] & 0x7f, data[2] & 0x7f);
+            break;
+        case 0xe0:
+            synth.pitchWheel(0, (data[2] << 7) + data[1] - 8192);
+            break;
+        }
+    }
+}
+
 int SfizzVstProcessor::convertVelocityFromFloat(float x)
 {
     return std::min(127, std::max(0, (int)(x * 127.0f)));
@@ -425,6 +463,17 @@ tresult PLUGIN_API SfizzVstProcessor::notify(Vst::IMessage* message)
         reply->getAttributes()->setBinary("File", _state.scalaFile.data(), _state.scalaFile.size());
         sendMessage(reply);
     }
+    else if (!std::strcmp(id, "MidiMessage")) {
+        const void* data = nullptr;
+        uint32 size = 0;
+        result = attr->getBinary("Data", data, size);
+        if (size < kMidiEventMaximumSize) {
+            if (_fifoMidiFromUi.size_free() >= sizeof(size) + size) {
+                _fifoMidiFromUi.put(size);
+                _fifoMidiFromUi.put(reinterpret_cast<const uint8_t*>(data), size);
+            }
+        }
+    }
 
     return result;
 }

vst/SfizzVstProcessor.h

@@ -35,6 +35,7 @@ public:
     void processParameterChanges(Vst::IParameterChanges& pc);
     void processControllerChanges(Vst::IParameterChanges& pc);
     void processEvents(Vst::IEventList& events);
+    void processMidiFromUi();
     static int convertVelocityFromFloat(float x);
 
     tresult PLUGIN_API notify(Vst::IMessage* message) override;
@@ -58,6 +59,7 @@ private:
     volatile bool _workRunning = false;
     Ring_Buffer _fifoToWorker;
     RTSemaphore _semaToWorker;
+    Ring_Buffer _fifoMidiFromUi;
     std::mutex _processMutex;
 
     // file modification periodic checker