Modified source engine (2017) developed by valve and leaked in 2020. Not for commercial purporses
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//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//=============================================================================//
#ifndef LOWPASSSTREAM_H
#define LOWPASSSTREAM_H
#ifdef _WIN32
#pragma once
#endif
// ------------------------------------------------------------------ //
// Default implementations of the operators used for averaging.
// ------------------------------------------------------------------ //
template< class DataType >
inline void SetToZero( DataType &data )
{
data = 0;
}
template< class DataType >
inline void AddSamples( DataType const &d1, DataType const &d2, DataType &out )
{
out = d1 + d2;
}
template< class DataType >
inline DataType DivideSample( DataType const &data, int factor )
{
return data / factor;
}
// This class does a simple low pass filter on data that you pass through it.
// You tell it the number of samples to hang onto and it will average that number
// of samples as you feed it data.
template< class DataType, int nSamples >
class CLowPassStream
{
public:
CLowPassStream();
// Add a sample to the list.
void AddSample( DataType const &data );
// Get the current average.
DataType GetCurrentAverage();
private:
DataType m_Samples[nSamples];
int m_iOutSample;
int m_nSamplesGotten; // incremented until it reaches nSamples.
// helps avoid the startup transient.
};
template< class DataType, int nSamples >
inline CLowPassStream<DataType, nSamples>::CLowPassStream()
{
for( int i=0; i < nSamples; i++ )
SetToZero( m_Samples[i] );
m_iOutSample = 0;
m_nSamplesGotten = 0;
}
template< class DataType, int nSamples >
inline void CLowPassStream<DataType, nSamples>::AddSample( DataType const &data )
{
m_Samples[m_iOutSample] = data;
++m_nSamplesGotten;
if( m_nSamplesGotten >= nSamples )
m_nSamplesGotten = nSamples;
++m_iOutSample;
if( m_iOutSample >= nSamples )
m_iOutSample = 0;
}
template< class DataType, int nSamples >
inline DataType CLowPassStream<DataType, nSamples>::GetCurrentAverage()
{
DataType data;
SetToZero( data );
for( int i=0; i < nSamples; i++ )
AddSamples( data, m_Samples[i], data );
return DivideSample( data, m_nSamplesGotten );
}
#endif // LOWPASSSTREAM_H