pitch to frequency and frequency to pitch conversions

logscaling.cpp

#define TUNINGFREQ 440.0

float p2f( float pitch ){
    return pow( 2.0, (pitch-69.0)/12.0 ) * TUNINGFREQ;
}

float f2p( float freq ){
    return (log2( freq / TUNINGFREQ ) * 12.0f ) + 69.0f;
}