/home/marsyas/marsyas/src/marsyas/Biquad.cpp

/*
 ** Copyright (C) 1998-2010 George Tzanetakis <gtzan@cs.uvic.ca>
 **  
 ** This program is free software; you can redistribute it and/or modify
 ** it under the terms of the GNU General Public License as published by
 ** the Free Software Foundation; either version 2 of the License, or
 ** (at your option) any later version.
 ** 
 ** This program is distributed in the hope that it will be useful,
 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 ** GNU General Public License for more details.
 ** 
 ** You should have received a copy of the GNU General Public License
 ** along with this program; if not, write to the Free Software 
 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "common.h" 
#include "Biquad.h"

using std::cout;
using std::endl;

using std::ostringstream;
using namespace Marsyas;

Biquad::Biquad(mrs_string name):MarSystem("Biquad",name)
{

    filter = new Filter("filter");

    b.create(3);    
    a.create(3);

    addControls();
}

Biquad::Biquad(const Biquad& orig): MarSystem(orig) 
{
 filter = new Filter("filter");
 b.create(3);
 a.create(3);
}

Biquad::~Biquad()
{
  delete filter;;
}


MarSystem* Biquad::clone() const 
{
    return new Biquad(*this);
}

void Biquad::addControls()
{

    addctrl("mrs_string/type","lowpass");
    addctrl("mrs_real/resonance", 1.0);
    addctrl("mrs_real/frequency", 500.0);

    setctrlState("mrs_string/type", true);
    setctrlState("mrs_real/resonance", true);
    setctrlState("mrs_real/frequency", true);

}

void Biquad::myUpdate(MarControlPtr sender)
{
    (void) sender;
    /* 
        Formula utilized is from "Audio-EQ-Cookbook" by Robert Bristow-Johnson
        http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
        Last retrieved March 20, 2007.
    */

    mrs_string type = getctrl("mrs_string/type")->to<mrs_string>();

    freq_ = getctrl("mrs_real/frequency")->to<mrs_real>();
    q_ = getctrl("mrs_real/resonance")->to<mrs_real>();
    
    fs_ = getctrl("mrs_real/israte")->to<mrs_real>();
    
    setctrl("mrs_real/osrate", fs_);
    setctrl("mrs_natural/onSamples", getctrl("mrs_natural/inSamples")->to<mrs_natural>());
    
    w0_ = 2 * PI * freq_ / fs_;

    

    if (type == "lowpass")
    {
        alpha_ = sin(w0_)/(2*q_);

        b(0) = (1 - cos(w0_))/2;
        b(1) =  1 - cos(w0_);
        b(2) = (1 - cos(w0_))/2;
        
        a(0) = 1 + alpha_;
        a(1) = -2 * cos(w0_); // Arian: was positive
        a(2) = 1 - alpha_;
        
        filter->updControl("mrs_realvec/ncoeffs", b);
        filter->updControl("mrs_realvec/dcoeffs", a);

    }
    else if (type == "bandpass")
    {
        alpha_ = sin(w0_)/(2*q_);

        b(0) = sin(w0_)/2;
        b(1) =  0;
        b(2) = -sin(w0_)/2;
        
        a(0) = 1 + alpha_;
        a(1) = -2 * cos(w0_); // Arian: was positive
        a(2) = 1 - alpha_;
        
        filter->updControl("mrs_realvec/ncoeffs", b);
        filter->updControl("mrs_realvec/dcoeffs", a);
    }
    else if (type == "highpass") 
    {
        b(0) = (1 + cos(w0_))/2;
        b(1) = -(1 + cos(w0_));
        b(2) =  (1 + cos(w0_))/2;
        a(0) =   1 + alpha_;
        a(1) =  -2*cos(w0_);
        a(2) =   1 - alpha_;
        filter->updControl("mrs_realvec/ncoeffs", b);
        filter->updControl("mrs_realvec/dcoeffs", a);
    }
    else if (type == "allpass")
    {
            alpha_ = sin(w0_)/(2*q_);
        
        b(0) = 1 - alpha_;
        b(1) = -2 * cos(w0_);
        b(2) = 1 + alpha_;
        
        a(0) = 1 + alpha_;
        a(1) = -2 * cos(w0_);
        a(2) = 1 - alpha_;
        
        
        filter->updControl("mrs_realvec/ncoeffs", b);
        filter->updControl("mrs_realvec/dcoeffs", a);

    }




    else
    {
        MRSWARN("BIQUAD: wrong type specified");
    
    }
    filter->setctrl("mrs_real/israte", fs_);
    filter->setctrl("mrs_real/osrate", fs_);
    filter->setctrl("mrs_natural/inObservations", getctrl("mrs_natural/inObservations")->to<mrs_natural>());
    filter->setctrl("mrs_natural/onObservations", getctrl("mrs_natural/onObservations")->to<mrs_natural>());
    filter->setctrl("mrs_natural/inSamples", getctrl("mrs_natural/inSamples")->to<mrs_natural>());
    filter->setctrl("mrs_natural/onSamples", getctrl("mrs_natural/onSamples")->to<mrs_natural>());
}


void Biquad::myProcess(realvec& in, realvec& out)
{
    filter->process(in,out);    

}

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