<?php
/*
    Copyright (C) 2004 Aaron Cyril Spike

    This file is part of FretFind 2-D.

    FretFind 2-D is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    FretFind 2-D is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with FretFind 2-D; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
/*
Base Frequency, frequency of $tunenote=0
Fn/(2^(n/12))=Fb

Frequency Fn of any note n
Fb*2^(n/12)=Fn

Note n of any frequency Fn
n=12*Log2(Fn/Fb)
*/
function freq2midipb($freq,$pbrsemitones=1,$pbrcents=0,$tunefreq=440,$tunenote=69)
{
	$pbrsemitones=$pbrsemitones<0?0:$pbrsemitones;
	$pbrsemitones=$pbrsemitones>24?24:$pbrsemitones;
	$pbrcents=$pbrcents<0?0:$pbrcents;
	$pbrcents=$pbrcents>100?100:$pbrcents;
	$tunenote=$tunenote<0?0:$tunenote;
	$tunenote=$tunenote>127?127:$tunenote;
	$tunefreq=$tunefreq<1?1:$tunefreq;
	$tunefreq=$tunefreq>22000?22000:$tunefreq;

	$basefreq=$tunefreq/pow(2,(($tunenote)/12));
	$precisenote=12*(log($freq/$basefreq)/log(2));
	$note=round($precisenote);
//	past assumption that I needed to center the wheel at 8192 to avoid negatives
//	must have been wrong
//	$pb=round(819200*($precisenote-$note)/((100*$pbrsemitones)+$pbrcents))+8192;
	$pb=round(819200*($precisenote-$note)/((100*$pbrsemitones)+$pbrcents))+0;
	return array('note'=>$note,'pb'=>$pb);
}
?>