Rack/plugins/community/repos/Autodafe/src/Biquad.h

//
//  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/2012/11/26/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

namespace rack_plugin_Autodafe {

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);

protected:
	void calcBiquad(void);

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

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

} // namespace rack_plugin_Autodafe

#endif // Biquad_h