FMOD_RESULT bmx_FMOD_System_GetSpectrum(FMOD_SYSTEM *system, BBArray * spectrumArray, int channelOffset, FMOD_DSP_FFT_WINDOW windowType) {
int size = spectrumArray->scales[0];
float arr[size];
FMOD_RESULT res = FMOD_System_GetSpectrum(system, &arr[0], size, channelOffset, windowType);
float *s=(float*)BBARRAYDATA( spectrumArray, spectrumArray->dims );
for (int i = 0; i < size; i ++) {
s[i] = arr[i];
}
return res;
}
// ----------------------------------------------------------------------------
float * ofxSoundGetSpectrum(int nBands)
{
ofxSoundInitialize();
// set to 0
for (int i = 0; i < 8192; i++){
fftInterpValues[i] = 0;
}
// check what the user wants vs. what we can do:
if (nBands > 8192){
ofLog(OF_LOG_ERROR, "error in ofxSoundGetSpectrum, the maximum number of bands is 8192 - you asked for %i we will return 8192", nBands);
nBands = 8192;
} else if (nBands <= 0){
ofLog(OF_LOG_ERROR, "error in ofxSoundSpectrum, you've asked for %i bands, minimum is 1", nBands);
return fftInterpValues;
}
// FMOD needs pow2
int nBandsToGet = ofNextPow2(nBands);
if (nBandsToGet < 64) nBandsToGet = 64; // can't seem to get fft of 32, etc from fmodex
// get the fft
FMOD_System_GetSpectrum(sys, fftSpectrum, nBandsToGet, 0, FMOD_DSP_FFT_WINDOW_HANNING);
// convert to db scale
for(int i = 0; i < nBandsToGet; i++){
fftValues[i] = 10.0f * (float)log10(1 + fftSpectrum[i]) * 2.0f;
}
// try to put all of the values (nBandsToGet) into (nBands)
// in a way which is accurate and preserves the data:
//
if (nBandsToGet == nBands){
for(int i = 0; i < nBandsToGet; i++){
fftInterpValues[i] = fftValues[i];
}
} else {
float step = (float)nBandsToGet / (float)nBands;
//float pos = 0;
// so for example, if nBands = 33, nBandsToGet = 64, step = 1.93f;
int currentBand = 0;
for(int i = 0; i < nBandsToGet; i++){
// if I am current band = 0, I care about (0+1) * step, my end pos
// if i > endPos, then split i with me and my neighbor
if (i >= ((currentBand+1)*step)){
// do some fractional thing here...
float fraction = ((currentBand+1)*step) - (i-1);
float one_m_fraction = 1 - fraction;
fftInterpValues[currentBand] += fraction * fftValues[i];
currentBand++;
// safety check:
if (currentBand >= nBands){
ofLog(OF_LOG_ERROR, "ofxSoundGetSpectrum - currentBand >= nBands");
}
fftInterpValues[currentBand] += one_m_fraction * fftValues[i];
} else {
// do normal things
fftInterpValues[currentBand] += fftValues[i];
}
}
// because we added "step" amount per band, divide to get the mean:
for (int i = 0; i < nBands; i++){
fftInterpValues[i] /= step;
if (fftInterpValues[i] > 1)fftInterpValues[i] = 1; // this seems "wrong"
}
}
return fftInterpValues;
}
