99 lines
2.2 KiB
C++
99 lines
2.2 KiB
C++
//========= Copyright Valve Corporation, All rights reserved. ============//
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//
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// Purpose:
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//
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// $NoKeywords: $
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//=============================================================================//
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#ifndef LOWPASSSTREAM_H
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#define LOWPASSSTREAM_H
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#ifdef _WIN32
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#pragma once
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#endif
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// ------------------------------------------------------------------ //
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// Default implementations of the operators used for averaging.
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// ------------------------------------------------------------------ //
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template< class DataType >
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inline void SetToZero( DataType &data )
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{
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data = 0;
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}
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template< class DataType >
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inline void AddSamples( DataType const &d1, DataType const &d2, DataType &out )
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{
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out = d1 + d2;
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}
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template< class DataType >
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inline DataType DivideSample( DataType const &data, int factor )
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{
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return data / factor;
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}
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// This class does a simple low pass filter on data that you pass through it.
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// You tell it the number of samples to hang onto and it will average that number
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// of samples as you feed it data.
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template< class DataType, int nSamples >
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class CLowPassStream
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{
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public:
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CLowPassStream();
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// Add a sample to the list.
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void AddSample( DataType const &data );
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// Get the current average.
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DataType GetCurrentAverage();
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private:
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DataType m_Samples[nSamples];
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int m_iOutSample;
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int m_nSamplesGotten; // incremented until it reaches nSamples.
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// helps avoid the startup transient.
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};
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template< class DataType, int nSamples >
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inline CLowPassStream<DataType, nSamples>::CLowPassStream()
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{
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for( int i=0; i < nSamples; i++ )
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SetToZero( m_Samples[i] );
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m_iOutSample = 0;
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m_nSamplesGotten = 0;
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}
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template< class DataType, int nSamples >
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inline void CLowPassStream<DataType, nSamples>::AddSample( DataType const &data )
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{
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m_Samples[m_iOutSample] = data;
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++m_nSamplesGotten;
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if( m_nSamplesGotten >= nSamples )
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m_nSamplesGotten = nSamples;
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++m_iOutSample;
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if( m_iOutSample >= nSamples )
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m_iOutSample = 0;
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}
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template< class DataType, int nSamples >
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inline DataType CLowPassStream<DataType, nSamples>::GetCurrentAverage()
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{
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DataType data;
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SetToZero( data );
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for( int i=0; i < nSamples; i++ )
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AddSamples( data, m_Samples[i], data );
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return DivideSample( data, m_nSamplesGotten );
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}
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#endif // LOWPASSSTREAM_H
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