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#include "Timbre.h"
#include "minorGems/util/stringUtils.h"
#include <math.h>
#include <stdio.h>
double twelthRootOfTwo = pow( 2, 1.0/12 );
// for major scale
// W, W, H, W, W, W, H
int halfstepMap[ 7 ] = { 0, 2, 4, 5, 7, 9, 11 };
// minor scale
// W,H,W,W,H,W,W
//int halfstepMap[ 7 ] = { 0, 2, 3, 5, 7, 8, 10 };
// gets frequency of note in our scale
double getFrequency( double inBaseFrequency, int inScaleNoteNumber ) {
int octavesUp = inScaleNoteNumber / 7;
int numHalfsteps = halfstepMap[ inScaleNoteNumber % 7 ] + octavesUp * 12;
return inBaseFrequency * pow( twelthRootOfTwo, numHalfsteps );
}
/*
Was used during testing
#include "minorGems/sound/formats/aiff.h"
int outputFileNumber = 0;
// outputs a wave table as an AIFF
void outputWaveTable( Sint16 *inTable, int inLength, int inSampleRate ) {
// generate the header
int headerSize;
unsigned char *aiffHeader =
getAIFFHeader( 1,
16,
inSampleRate,
inLength,
&headerSize );
char *fileName = autoSprintf( "waveTable%d.aiff", outputFileNumber );
outputFileNumber++;
FILE *aiffFile = fopen( fileName, "wb" );
delete [] fileName;
//printf( "Header size = %d\n", headerSize );
fwrite( aiffHeader, 1, headerSize, aiffFile );
delete [] aiffHeader;
for( int i=0; i<inLength; i++ ) {
Sint16 val = inTable[i];
unsigned char msb = val >> 8 & 0xFF;
unsigned char lsb = val && 0xFF;
fwrite( &msb, 1, 1, aiffFile );
fwrite( &lsb, 1, 1, aiffFile );
}
fclose( aiffFile );
}
*/
Timbre::Timbre( int inSampleRate,
double inLoudness,
double inBaseFrequency,
int inNumWaveTableEntries,
double( *inWaveFunction )( double ) )
: mNumWaveTableEntries( inNumWaveTableEntries ),
mWaveTable( new Sint16*[ inNumWaveTableEntries ] ),
mWaveTableLengths( new int[ inNumWaveTableEntries ] ) {
// build wave table for each possible pitch in image
for( int i=0; i<mNumWaveTableEntries; i++ ) {
double freq = getFrequency( inBaseFrequency, i );
double period = 1.0 / freq;
// wave table contains more than one period to more
// accurately represent a signal with frequency freq
int periodsInTable = 5;
int tableLength = (int)( periodsInTable * period * inSampleRate );
mWaveTableLengths[i] = tableLength;
mWaveTable[i] = new Sint16[ tableLength ];
// store double samples in temp table so we can compute
// max value for normalization
double *tempTable = new double[ tableLength ];
double maxValue = 0;
int s;
for( s=0; s<tableLength; s++ ) {
//double t = (double)s / (double)inSampleRate;
//double waveValue = inWaveFunction( 2 * M_PI * t * freq );
// base t on table length to ensure a perfect set of periods
// in our table. Otherwise, we hear clicks when table is looped
double t = (double)s / (double)(tableLength);
double waveValue = inWaveFunction( 2 * M_PI * t * periodsInTable );
tempTable[s] = waveValue;
// track max value
if( waveValue > maxValue ) {
maxValue = waveValue;
}
else if( -waveValue > maxValue ) {
maxValue = -waveValue;
}
}
// now normalize and convert to int
for( s=0; s<tableLength; s++ ) {
double waveValue = tempTable[s] * inLoudness / maxValue;
// convert to int
mWaveTable[i][s] = (Sint16)( 32767 * waveValue );
}
delete [] tempTable;
mWaveTableLengths[i] = tableLength;
// to examine waveforms for testing
// outputWaveTable( mWaveTable[i], tableLength, inSampleRate );
}
}
Timbre::~Timbre() {
delete [] mWaveTableLengths;
for( int i=0; i<mNumWaveTableEntries; i++ ) {
delete [] mWaveTable[i];
}
delete [] mWaveTable;
}
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