//
// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
// Creation Date: Sat Jan  1 20:29:45 PST 2005
// Last Modified: Sat Jan  1 20:37:28 PST 2005
// Filename:      ...midiio/doc/windowsmidi/keymidi/keymidi.c
// URL:           http://midiio.sapp.org/doc/windowsmidi/keymidi/keymidi.c
// Syntax:        C; Visual C/C++ 5/6
//
// Description:   The example program shows how to open MIDI output,
//                send a MIDI message, and close MIDI output.
//                When you press a key on the computer keyboard, a MIDI
//                note will be either turned on or off.
//

#include <conio.h>     /* include for kbhit() and getch() functions */
#include <stdio.h>     /* for printf() function */

#include <windows.h>   /* required before including mmsystem.h */
#include <mmsystem.h>  /* multimedia functions (such as MIDI) for Windows */

int main(int argc, char** argv) {
   int ckey;           // storage for the current keyboard key being pressed
   int notestate = 0;  // keeping track of when the note is on or off
   int velocity = 100; // MIDI note velocity parameter value
   int midiport;       // select which MIDI output port to open
   int flag;           // monitor the status of returning functions
   HMIDIOUT device;    // MIDI device interface for sending MIDI output
 
   // variable which is both an integer and an array of characters:
   union { unsigned long word; unsigned char data[4]; } message;
   // message.data[0] = command byte of the MIDI message, for example: 0x90
   // message.data[1] = first data byte of the MIDI message, for example: 60
   // message.data[2] = second data byte of the MIDI message, for example 100
   // message.data[3] = not used for any MIDI messages, so set to 0
   message.data[0] = 0x90;  // MIDI note-on message (requires to data bytes)
   message.data[1] = 60;    // MIDI note-on message: Key number (60 = middle C)
   message.data[2] = 100;   // MIDI note-on message: Key velocity (100 = loud)
   message.data[3] = 0;     // Unused parameter

   // Assign the MIDI output port number (from input or default to 0)
   if (argc < 2) {
      midiport = 0;
   } else {
      midiport = atoi(argv[1]);
   }
   printf("MIDI output port set to %d.\n", midiport);

   // Open the MIDI output port
   flag = midiOutOpen(&device, midiport, 0, 0, CALLBACK_NULL);
   if (flag != MMSYSERR_NOERROR) {
      printf("Error opening MIDI Output.\n");
      return 1;
   }

   // Main event loop
   printf("Press \"q\" to quit.\n");
   while (1) {         // event loop
      if (kbhit()) {   // If a key on the computer keyboard has been pressed 
         ckey = getch();
         if (notestate == 0) {
            // Note is currently off, turn on note.
            message.data[2] = velocity;
            notestate = 1;
            printf("Note turned ON.\n");
         } else {
            // Note is currently on, turn off note.
            message.data[2] = 0;  // 0 velocity = note off
            notestate = 0;
            printf("Note turned OFF.\n");
         }
         flag = midiOutShortMsg(device, message.word);
         if (flag != MMSYSERR_NOERROR) {
            printf("Warning: MIDI Output is not open.\n");
         }
         if (ckey == 'q') break;
      }
   }

   // turn any MIDI notes currently playing:
   midiOutReset(device);

   // Remove any data in MIDI device and close the MIDI Output port
   midiOutClose(device);

   return 0;
}


/* Windows I/O functions used in this program:
 *
 * Keyboard Console Functions:
 * int kbhit(void) -- Returns true if a key on the computer keyboard has
 *                    been pressed, or false if no key has been pressed.
 * int getch(void) -- Returns the key which has been pressed on the computer
 *                    keyboard.  Returns -1 if there was not key press.
 *
 * MIDI Output Functions:
 * midiOutOpen     -- http://msdn.microsoft.com/library/en-us/multimed/htm/_win32_midioutopen.asp
 * midiOutShortMsg -- http://msdn.microsoft.com/library/en-us/multimed/htm/_win32_midioutshortmsg.asp
 * midiOutClose    -- http://msdn.microsoft.com/library/en-us/multimed/htm/_win32_midioutclose.asp
 * midiOutReset    -- http://msdn.microsoft.com/library/en-us/multimed/htm/_win32_midioutclose.asp
 */