Method FillFirstWindow

libraries/lib-fft/SpectrumTransformer.cpp:194–229

}

void SpectrumTransformer::FillFirstWindow()
{
   // Transform samples to frequency domain, windowed as needed
   {
      auto pFFTBuffer = mFFTBuffer.data(), pInWaveBuffer = mInWaveBuffer.data();
      if (mInWindow.size() > 0) {
         auto pInWindow = mInWindow.data();
         for (size_t ii = 0; ii < mWindowSize; ++ii)
            *pFFTBuffer++ = *pInWaveBuffer++ * *pInWindow++;
      }
      else
         memmove(pFFTBuffer, pInWaveBuffer, mWindowSize * sizeof(float));
   }
   RealFFTf(mFFTBuffer.data(), hFFT.get());

   auto &record = Nth(0);

   // Store real and imaginary parts for later inverse FFT
   {
      float *pReal = &record.mRealFFTs[1];
      float *pImag = &record.mImagFFTs[1];
      int *pBitReversed = &hFFT->BitReversed[1];
      const auto last = mSpectrumSize - 1;
      for (size_t ii = 1; ii < last; ++ii) {
         const int kk = *pBitReversed++;
         *pReal++ = mFFTBuffer[kk];
         *pImag++ = mFFTBuffer[kk + 1];
      }
      // DC and Fs/2 bins need to be handled specially
      const float dc = mFFTBuffer[0];
      record.mRealFFTs[0] = dc;

      const float nyquist = mFFTBuffer[1];
      record.mImagFFTs[0] = nyquist; // For Fs/2, not really imaginary
   }
}

void SpectrumTransformer::RotateWindows()
{