Method SnappingProcessor

src/SpectralDataManager.cpp:216–253

 }

bool SpectralDataManager::Worker::SnappingProcessor(SpectrumTransformer &transformer) {
   auto &worker = static_cast<Worker &>(transformer);
   // Compute power spectrum in the newest window
   {
      MyWindow &record = worker.NthWindow(0);
      float *pSpectrum = &record.mSpectrums[0];
      const double dc = record.mRealFFTs[0];
      *pSpectrum++ = dc * dc;
      float *pReal = &record.mRealFFTs[1], *pImag = &record.mImagFFTs[1];
      for (size_t nn = worker.mSpectrumSize - 2; nn--;) {
         const double re = *pReal++, im = *pImag++;
         *pSpectrum++ = re * re + im * im;
      }
      const double nyquist = record.mImagFFTs[0];
      *pSpectrum = nyquist * nyquist;

      const double &sr = worker.mSnapSamplingRate;
      const double nyquistRate = sr / 2;
      const double &threshold = worker.mSnapThreshold;
      const double &spectrumSize = worker.mSpectrumSize;
      const int &targetBin = worker.mSnapTargetFreqBin;

      int binBound = spectrumSize * threshold;
      float maxValue = std::numeric_limits<float>::min();

      // Skip the first and last bin
      for(int i = -binBound; i < binBound; i++){
         int idx = std::clamp(targetBin + i, 0, static_cast<int>(spectrumSize - 1));
         if(record.mSpectrums[idx] > maxValue){
            maxValue = record.mSpectrums[idx];
            // Update the return frequency
            worker.mSnapReturnFreqBin = idx;
         }
      }
   }

   return true;
}

bool SpectralDataManager::Worker::OvertonesProcessor(SpectrumTransformer &transformer) {
   auto &worker = static_cast<Worker &>(transformer);