protected virtual void UpdateFrequencyMapping(int bandIndex)
{
BandData _CurrentBand = _BandFrecuencies[bandIndex];
_CurrentBand._maximumFrequencyIndex =
Math.Min(_spectrumProvider.GetFftBandIndex(_CurrentBand._maximumFrequency) + 1, _maxFftIndex);
_CurrentBand._minimumFrequencyIndex =
Math.Min(_spectrumProvider.GetFftBandIndex(_CurrentBand._minimumFrequency), _maxFftIndex);
int actualResolution = SpectrumResolution;
int indexCount = _CurrentBand._maximumFrequencyIndex - _CurrentBand._minimumFrequencyIndex;
double linearIndexBucketSize = Math.Round(indexCount / (double)actualResolution, 3);
_spectrumIndexMax = _spectrumIndexMax.CheckBuffer(actualResolution, true);
_spectrumLogScaleIndexMax = _spectrumLogScaleIndexMax.CheckBuffer(actualResolution, true);
//?????? Isnt this one?
//double maxLog = Math.Log(actualResolution, actualResolution);
double maxLog = 1.0;
for (int i = 1; i < actualResolution; i++)
{
int logIndex =
(int)((maxLog - Math.Log((actualResolution + 1) - i, (actualResolution + 1))) * indexCount) +
_CurrentBand._minimumFrequencyIndex;
_spectrumIndexMax[i - 1] = _CurrentBand._minimumFrequencyIndex + (int)(i * linearIndexBucketSize);
_spectrumLogScaleIndexMax[i - 1] = logIndex;
}
if (actualResolution > 0)
{
_spectrumIndexMax[_spectrumIndexMax.Length - 1] =
_spectrumLogScaleIndexMax[_spectrumLogScaleIndexMax.Length - 1] = _CurrentBand._maximumFrequencyIndex;
}
_BandFrecuencies[bandIndex] = _CurrentBand;
}
protected virtual SpectrumPointData[] CalculateSpectrumPoints(double maxValue, float[] fftBuffer, int bandIndex)
{
BandData _CurrentBand = _BandFrecuencies[bandIndex];
var dataPoints = new List <SpectrumPointData>();
double value0 = 0, value = 0;
double lastValue = 0;
double actualMaxValue = maxValue;
int spectrumPointIndex = 0;
for (int i = _CurrentBand._minimumFrequencyIndex; i <= _CurrentBand._maximumFrequencyIndex; i++)
{
switch (ScalingStrategy)
{
case ScalingStrategy.Decibel:
value0 = (((20 * Math.Log10(fftBuffer[i])) - MinDbValue) / DbScale) * actualMaxValue;
break;
case ScalingStrategy.Linear:
value0 = (fftBuffer[i] * ScaleFactorLinear) * actualMaxValue;
break;
case ScalingStrategy.Sqrt:
value0 = ((Math.Sqrt(fftBuffer[i])) * ScaleFactorSqr) * actualMaxValue;
break;
}
bool recalc = true;
value = Math.Max(0, Math.Max(value0, value));
while (spectrumPointIndex <= _spectrumIndexMax.Length - 1 &&
i ==
(IsXLogScale
? _spectrumLogScaleIndexMax[spectrumPointIndex]
: _spectrumIndexMax[spectrumPointIndex]))
{
if (!recalc)
{
value = lastValue;
}
if (value > maxValue)
{
value = maxValue;
}
if (_useAverage && spectrumPointIndex > 0)
{
value = (lastValue + value) / 2.0;
}
dataPoints.Add(new SpectrumPointData {
SpectrumPointIndex = spectrumPointIndex, Value = value
});
lastValue = value;
value = 0.0;
spectrumPointIndex++;
recalc = false;
}
//value = 0;
}
return(dataPoints.ToArray());
}
