view projects/d-box/Biquad.h @ 45:579c86316008 newapi

Major API overhaul. Moved to a single data structure for handling render functions. Functionally, generally similar except for scheduling within PRU loop function, which now uses interrupts from the PRU rather than polling. This requires an updated kernel.

//
//  Biquad.h
//
//  Created by Nigel Redmon on 11/24/12
//  EarLevel Engineering: earlevel.com
//  Copyright 2012 Nigel Redmon
//
//  For a complete explanation of the Biquad code:
//  http://www.earlevel.com/main/2012/11/25/biquad-c-source-code/
//
//  License:
//
//  This source code is provided as is, without warranty.
//  You may copy and distribute verbatim copies of this document.
//  You may modify and use this source code to create binary code
//  for your own purposes, free or commercial.
//

#ifndef Biquad_h
#define Biquad_h

enum {
    bq_type_lowpass = 0,
    bq_type_highpass,
    bq_type_bandpass,
    bq_type_notch,
    bq_type_peak,
    bq_type_lowshelf,
    bq_type_highshelf
};

class Biquad {
public:
    Biquad();
    Biquad(int type, double Fc, double Q, double peakGainDB);
    ~Biquad();
    void setType(int type);
    void setQ(double Q);
    void setFc(double Fc);
    void setPeakGain(double peakGainDB);
    void setBiquad(int type, double Fc, double Q, double peakGain);
    float process(float in);
    
    double getQ();
    double getFc();
    double getPeakGain();

    double getStartingQ();
	double getStartingFc();
	double getStartingPeakGain();

protected:
    void calcBiquad(void);

    int type;
    double a0, a1, a2, b1, b2;
    double Fc, Q, peakGain;
    double startFc, startQ, startPeakGain;
    double z1, z2;
};

inline double Biquad::getQ()
{
	return Q;
}

inline double Biquad::getFc()
{
	return Fc;
}

inline double Biquad::getPeakGain()
{
	return peakGain;
}

inline double Biquad::getStartingQ()
{
	return startQ;
}

inline double Biquad::getStartingFc()
{
	return startFc;
}

inline double Biquad::getStartingPeakGain()
{
	return startPeakGain;
}

inline float Biquad::process(float in) {
    double out = in * a0 + z1;
    z1 = in * a1 + z2 - b1 * out;
    z2 = in * a2 - b2 * out;
    return out;
}

#endif // Biquad_h