c@121: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
c@121: /*
c@121:     Constant-Q library
c@121:     Copyright (c) 2013-2014 Queen Mary, University of London
c@121: 
c@121:     Permission is hereby granted, free of charge, to any person
c@121:     obtaining a copy of this software and associated documentation
c@121:     files (the "Software"), to deal in the Software without
c@121:     restriction, including without limitation the rights to use, copy,
c@121:     modify, merge, publish, distribute, sublicense, and/or sell copies
c@121:     of the Software, and to permit persons to whom the Software is
c@121:     furnished to do so, subject to the following conditions:
c@121: 
c@121:     The above copyright notice and this permission notice shall be
c@121:     included in all copies or substantial portions of the Software.
c@121: 
c@121:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
c@121:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
c@121:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
c@121:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
c@121:     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
c@121:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
c@121:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
c@121: 
c@121:     Except as contained in this notice, the names of the Centre for
c@121:     Digital Music; Queen Mary, University of London; and Chris Cannam
c@121:     shall not be used in advertising or otherwise to promote the sale,
c@121:     use or other dealings in this Software without prior written
c@121:     authorization.
c@121: */
c@121: 
c@121: #include "Pitch.h"
c@121: 
c@121: #include <math.h>
c@121: 
c@121: float
c@121: Pitch::getFrequencyForPitch(int midiPitch,
c@121: 			    float centsOffset,
c@121: 			    float concertA)
c@121: {
c@121:     float p = float(midiPitch) + (centsOffset / 100);
c@121:     return concertA * powf(2.0, (p - 69.0) / 12.0);
c@121: }
c@121: 
c@121: int
c@121: Pitch::getPitchForFrequency(float frequency,
c@121: 			    float *centsOffsetReturn,
c@121: 			    float concertA)
c@121: {
c@121:     float p = 12.0 * (log(frequency / (concertA / 2.0)) / log(2.0)) + 57.0;
c@121: 
c@121:     int midiPitch = int(p + 0.00001);
c@121:     float centsOffset = (p - midiPitch) * 100.0;
c@121: 
c@121:     if (centsOffset >= 50.0) {
c@121: 	midiPitch = midiPitch + 1;
c@121: 	centsOffset = -(100.0 - centsOffset);
c@121:     }
c@121:     
c@121:     if (centsOffsetReturn) *centsOffsetReturn = centsOffset;
c@121:     return midiPitch;
c@121: }
c@121: