🚀 go-pugleaf

On Sun, 18 May 2003 15:08:04 -0700, "Nicholas Gessler"
<gessler@ucla.edu> wrote:

>I am looking for an extremely simple example of using MIDI.
>Simply the MIDI equivalent of Beep (frequency, duration) which does NOT work
>with Win95.
>Can someone just provide me with a few lines of code to get me started?
>
>Thanks,
>Nick
>

Usually I don't think of MIDI as being a replacement for the Beep
function (I think it would more natural to implement a Beep function
using waveform audio functions).

Here is a crude attempt at a MIDI based beep.  I don't know how
correct the FreqToNote function is, I just Googled for it.

#include <windows.h>
#include <mmsystem.h>
#include <math.h>

#define NOTEON(c, n, v) ( 0x90 | (c) | ((n) << 8) | ((v) <<16) )
#define CHANGE_INSTR(c, i) ( 0xC0 | (c) | ((i) << 8) )

DWORD FreqToNote(DWORD frequency)
{
	double freq;
	int x;

	for(x = 0; x < 127; x++)
	{
		freq = (440.0 / 32) * pow(2,((x - 9) / 12));
		if (freq > frequency)
			break;
	}
	
	return x;
}
void MIDIBeep(DWORD frequency, DWORD duration)
{
	HMIDIOUT hMidiOut;
	UINT dev = MIDI_MAPPER;

	midiOutOpen(&hMidiOut, dev, NULL, 0, CALLBACK_NULL);
	midiOutShortMsg(hMidiOut, CHANGE_INSTR(0, 56) /* trumpet */);
	midiOutShortMsg(hMidiOut, NOTEON(0, FreqToNote(frequency),
0x7F));
	Sleep(duration);
	midiOutReset(hMidiOut);
	midiOutClose(hMidiOut);
}

int main(int,char*)
{
	Beep(600,1000);
	MIDIBeep(600,1000);
	return 0;
}
Chris Hill
Chris244@aol.com