A set of of utilities for using MIDI Input with AutoHotkey

code gathered from this AutoHotkey forum discussion

this repo adds a 64 bit midi_in.dll

Here's a list of all exported functions in midi_in.dll with some explanation of how they (should)work.

int open(HWND targetWindowHandle, int deviceID)
	
	targetWindowHandle should be a handle to the script itself
	deviceID is passed to winmm.dll\midiInOpen unchecked so you'll have to check possible values with winmm.dll\midiInGetNumDevs and winmm.dll\midiInGetDevCaps


	Returns:
	0 - success
	50 - window handle was null
	60 - hMidiIn was not null
	anything else - error code from winmm.dll\midiInOpen



int close()

	Closes the midi in device (unless already closed) and resets the internal midiIn handle
	This function must be called before openMidiIn can be called again.
	Unloading (detatching) the DLL automatically calls this function.


void start()

	calls midiInStart(hMidiIn)

void stop()

	calls midiInStop(hMidiIn)

int getNumDevs()

	calls midiInGetNumDevs()
	returns the number of installed midi input devices
	
char* getDevName(int deviceID)
	
	returns a midi input device name

These are used to determine when closing and opening midi input is necessary

char* getCurDevName()
int getCurDevID()


The midi data is sent to the ahk script with windows messages.

Which messages are sent on which midi input are specified by "adding listeners". Internally these functions just write message number values in 2d and 1d arrays (e.g. notes x channels, or just channel for pitch wheel)

listenNoteRange(int rangeStart, int rangeEnd, int modeFlags, int channel, int msgNumber)
	
	wParam - note number
	lParam - velocity (0x00 - 0x7F)

	rangeStart, rangeEnd
		midi note numbers (0x00 - 0x7F)

	msgNumber
		the (first) message number to be sent

	modeFlags (default = 0)
		& 0x01 - use increasing msgNumbers for subsequent notes
		& 0x02 - ignore black keys on note range
		& 0x04 - ignore white keys on note range

	channel
		if 0, listen to all channels (default), otherwise 1-16
	

listenNote(int noteNumber, int channel, int msgNumber

int listenCC(int ccNumber, int channel, int msgNumber)

	wParam - cc number (0x00 - 0x7F)
	lParam - cc value (0x00 - 0x7F)


int listenWheel(int channel, int msgNumber)

	wParam - wheel position
		value range is 0x0000 - 0x3FFF, middle = 0x2000		


int listenChanAT(int channel, int msgNumber)

	wParam - channel aftertouch value (0x00 - 0x7F)


void removeAllListeners()

	Resets all "listener" arrays to zero. Not really sure if this is useful.

The dll also stores the most recent values of controller data even when nothing is sent forward.

int getNoteOn(int noteNumber, int channel)

	Returns 0 if key is up, otherwise the last key down velocity

int getCC(int ccNumber, int channel)
int getWheel(int channel)
int getChanAT(int channel)