#pragma once
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#include <cmath>
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/**
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* First order filter for smoothing parameter changes
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*
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*/
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class FirstOrderSmoother
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{
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public:
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FirstOrderSmoother()
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{
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}
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~FirstOrderSmoother()
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{
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}
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/**
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* @brief Prepares filter for playback
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*
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* @param smoothingTimeInMs Amount of time to reach target value in milliseconds
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* @param samplingRate Current sampling rate
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*/
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void prepare(float smoothingTimeInMs, float samplingRate)
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{
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const float c_twoPi = 6.283185307179586476925286766559f;
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a = exp(-c_twoPi / (smoothingTimeInMs * 0.001f * samplingRate));
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b = 1.0f - a;
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z = 0.0f;
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};
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/**
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* @brief Processes a single sample
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*
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* @param in Target value to reach
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*/
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inline float process(float in)
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{
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z = (in * b) + (z * a);
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return z;
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}
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private:
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float a;
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float b;
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float z;
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};
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