OnePole.h

/*
 * Adapted from: http://www.earlevel.com/main/2012/12/15/a-one-pole-filter/
 *
 *      by: Adán L. Benito
 *      on: November 2018
 *      original code by Nigel Redmon
 *
 */
#pragma once
 
class OnePole
{
public:
        typedef enum {
                LOWPASS,
                HIGHPASS,
        } Type;
        OnePole();
        OnePole(float cutoff, float samplingRate, Type type = LOWPASS);
        int setup(float cutoff, float samplingRate, Type type = LOWPASS);
        void setFilter(float cutoff, Type type = LOWPASS);
        float process(float input);
private:
        float _samplingRate;
        int _type;
        float a0, b1, ym1;
        void setFc(float cutoff);
};