Add MIDI controller device index to InputEventMIDI.device property.

It is possible to query the OS for the connected MIDI controllers,
but the event messages' device field was not being used. This implements
controller index being sent in InputEventMIDI messages in the device
property, matching the index from OS.get_connected_midi_inputs().

Based on the work done by @ramdor.

Closes godotengine/godot-proposals#7733

Co-authored-by: Richie <richie_github@grange-lane.co.uk>

core/os/midi_driver.cpp

@@ -42,9 +42,10 @@ void MIDIDriver::set_singleton() {
 	singleton = this;
 }
 
-void MIDIDriver::receive_input_packet(uint64_t timestamp, uint8_t *data, uint32_t length) {
+void MIDIDriver::receive_input_packet(int device_index, uint64_t timestamp, uint8_t *data, uint32_t length) {
 	Ref<InputEventMIDI> event;
 	event.instantiate();
+	event->set_device(device_index);
 	uint32_t param_position = 1;
 
 	if (length >= 1) {

core/os/midi_driver.h

@@ -51,7 +51,7 @@ public:
 
 	virtual PackedStringArray get_connected_inputs();
 
-	static void receive_input_packet(uint64_t timestamp, uint8_t *data, uint32_t length);
+	static void receive_input_packet(int device_index, uint64_t timestamp, uint8_t *data, uint32_t length);
 
 	MIDIDriver();
 	virtual ~MIDIDriver() {}

drivers/alsamidi/midi_driver_alsamidi.cpp

@@ -82,13 +82,13 @@ size_t MIDIDriverALSAMidi::msg_expected_data(uint8_t status_byte) {
 }
 
 void MIDIDriverALSAMidi::InputConnection::parse_byte(uint8_t byte, MIDIDriverALSAMidi &driver,
-		uint64_t timestamp) {
+		uint64_t timestamp, int device_index) {
 	switch (msg_category(byte)) {
 		case MessageCategory::RealTime:
 			// Real-Time messages are single byte messages that can
 			// occur at any point.
 			// We pass them straight through.
-			driver.receive_input_packet(timestamp, &byte, 1);
+			driver.receive_input_packet(device_index, timestamp, &byte, 1);
 			break;
 
 		case MessageCategory::Data:
@@ -100,7 +100,7 @@ void MIDIDriverALSAMidi::InputConnection::parse_byte(uint8_t byte, MIDIDriverALS
 
 				// Forward a complete message and reset relevant state.
 				if (received_data == expected_data) {
-					driver.receive_input_packet(timestamp, buffer, received_data + 1);
+					driver.receive_input_packet(device_index, timestamp, buffer, received_data + 1);
 					received_data = 0;
 
 					if (msg_category(buffer[0]) != MessageCategory::Voice) {
@@ -130,13 +130,13 @@ void MIDIDriverALSAMidi::InputConnection::parse_byte(uint8_t byte, MIDIDriverALS
 			expected_data = msg_expected_data(byte);
 			skipping_sys_ex = false;
 			if (expected_data == 0) {
-				driver.receive_input_packet(timestamp, &byte, 1);
+				driver.receive_input_packet(device_index, timestamp, &byte, 1);
 			}
 			break;
 	}
 }
 
-int MIDIDriverALSAMidi::InputConnection::read_in(MIDIDriverALSAMidi &driver, uint64_t timestamp) {
+int MIDIDriverALSAMidi::InputConnection::read_in(MIDIDriverALSAMidi &driver, uint64_t timestamp, int device_index) {
 	int ret;
 	do {
 		uint8_t byte = 0;
@@ -147,7 +147,7 @@ int MIDIDriverALSAMidi::InputConnection::read_in(MIDIDriverALSAMidi &driver, uin
 				ERR_PRINT("snd_rawmidi_read error: " + String(snd_strerror(ret)));
 			}
 		} else {
-			parse_byte(byte, driver, timestamp);
+			parse_byte(byte, driver, timestamp, device_index);
 		}
 	} while (ret > 0);
 
@@ -165,7 +165,7 @@ void MIDIDriverALSAMidi::thread_func(void *p_udata) {
 		size_t connection_count = md->connected_inputs.size();
 
 		for (size_t i = 0; i < connection_count; i++) {
-			connections[i].read_in(*md, timestamp);
+			connections[i].read_in(*md, timestamp, (int)i);
 		}
 
 		md->unlock();

drivers/alsamidi/midi_driver_alsamidi.h

@@ -58,7 +58,7 @@ class MIDIDriverALSAMidi : public MIDIDriver {
 				rawmidi_ptr{ midi_in } {}
 
 		// Read in and parse available data, forwarding any complete messages through the driver.
-		int read_in(MIDIDriverALSAMidi &driver, uint64_t timestamp);
+		int read_in(MIDIDriverALSAMidi &driver, uint64_t timestamp, int device_index);
 
 		snd_rawmidi_t *rawmidi_ptr = nullptr;
 
@@ -68,7 +68,7 @@ class MIDIDriverALSAMidi : public MIDIDriver {
 		size_t expected_data = 0;
 		size_t received_data = 0;
 		bool skipping_sys_ex = false;
-		void parse_byte(uint8_t byte, MIDIDriverALSAMidi &driver, uint64_t timestamp);
+		void parse_byte(uint8_t byte, MIDIDriverALSAMidi &driver, uint64_t timestamp, int device_index);
 	};
 
 	Vector<InputConnection> connected_inputs;

drivers/coremidi/midi_driver_coremidi.cpp

@@ -39,8 +39,9 @@
 
 void MIDIDriverCoreMidi::read(const MIDIPacketList *packet_list, void *read_proc_ref_con, void *src_conn_ref_con) {
 	MIDIPacket *packet = const_cast<MIDIPacket *>(packet_list->packet);
+	int *device_index = static_cast<int *>(src_conn_ref_con);
 	for (UInt32 i = 0; i < packet_list->numPackets; i++) {
-		receive_input_packet(packet->timeStamp, packet->data, packet->length);
+		receive_input_packet(*device_index, packet->timeStamp, packet->data, packet->length);
 		packet = MIDIPacketNext(packet);
 	}
 }
@@ -64,7 +65,7 @@ Error MIDIDriverCoreMidi::open() {
 	for (int i = 0; i < sources; i++) {
 		MIDIEndpointRef source = MIDIGetSource(i);
 		if (source) {
-			MIDIPortConnectSource(port_in, source, (void *)this);
+			MIDIPortConnectSource(port_in, source, static_cast<void *>(&i));
 			connected_sources.insert(i, source);
 		}
 	}

drivers/winmidi/midi_driver_winmidi.cpp

@@ -36,7 +36,7 @@
 
 void MIDIDriverWinMidi::read(HMIDIIN hMidiIn, UINT wMsg, DWORD_PTR dwInstance, DWORD_PTR dwParam1, DWORD_PTR dwParam2) {
 	if (wMsg == MIM_DATA) {
-		receive_input_packet((uint64_t)dwParam2, (uint8_t *)&dwParam1, 3);
+		receive_input_packet((int)dwInstance, (uint64_t)dwParam2, (uint8_t *)&dwParam1, 3);
 	}
 }
 
@@ -44,7 +44,7 @@ Error MIDIDriverWinMidi::open() {
 	for (UINT i = 0; i < midiInGetNumDevs(); i++) {
 		HMIDIIN midi_in;
 
-		MMRESULT res = midiInOpen(&midi_in, i, (DWORD_PTR)read, (DWORD_PTR)this, CALLBACK_FUNCTION);
+		MMRESULT res = midiInOpen(&midi_in, i, (DWORD_PTR)read, (DWORD_PTR)i, CALLBACK_FUNCTION);
 		if (res == MMSYSERR_NOERROR) {
 			midiInStart(midi_in);
 			connected_sources.insert(i, midi_in);