private void SetupCoeffs()
{
var window = WWWindowFunc.BlackmanWindow(WindowLength);
// ループ処理を簡単にするため最初と最後に0を置く。
mCoeffs = new double[1 + WindowLength + 1];
int center = WindowLength / 2;
for (int i = 0; i < WindowLength / 2 + 1; ++i)
{
int numerator = i;
int denominator = Factor;
int numeratorReminder = numerator % (denominator * 2);
if (numerator == 0)
{
mCoeffs[1 + center + i] = 1.0f;
}
else if (numerator % denominator == 0)
{
// sinc(180 deg) == 0, sinc(360 deg) == 0, ...
mCoeffs[1 + center + i] = 0.0f;
}
else
{
mCoeffs[1 + center + i] = Math.Sin(Math.PI * numeratorReminder / denominator)
/ (Math.PI * numerator / denominator)
* window[center + i];
}
mCoeffs[1 + center - i] = mCoeffs[1 + center + i];
}
}
public OverlappedFft(int fftLength)
{
mFftLength = fftLength;
mFft = new WWRadix2Fft(mFftLength);
mOverlapInputSamples = new double[mFftLength / 2];
mWindow = WWWindowFunc.BlackmanWindow(mFftLength / 2 - 1);
mLastOutputSamplesTail = new double[mFftLength / mSpliceDenominator];
mFirstTime = true;
}