/* sc4pd 
   Decay~, Decay

   Copyright (c) 2004 Tim Blechmann.                                       

   This code is derived from:
	SuperCollider real time audio synthesis system
    Copyright (c) 2002 James McCartney. All rights reserved.
	http://www.audiosynth.com


   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.

   Based on:
     PureData by Miller Puckette and others.
         http://www.crca.ucsd.edu/~msp/software.html
     FLEXT by Thomas Grill
         http://www.parasitaere-kapazitaeten.net/ext
     SuperCollider by James McCartney
         http://www.audiosynth.com
     
   Coded while listening to: AMM: AMMMusic 1966
   
*/

#include "sc4pd.hpp"

/* todo: linear interpolation is broken */
/* ------------------------ Decay~ -----------------------------*/

class Decay_ar
    :public sc4pd_dsp
{
    FLEXT_HEADER(Decay_ar,sc4pd_dsp);

public:
    Decay_ar(int argc,t_atom * argv);

protected:
    virtual void m_signal(int n, t_sample *const *in, t_sample *const *out);
    virtual void m_dsp(int n, t_sample *const *in, t_sample *const *out);
    void m_set(float f);

private:
    FLEXT_CALLBACK_F(m_set);
    float m_b1;                       //leak
    float m_y1;                       //z-1
    float decayTime;
};

FLEXT_LIB_DSP_V("Decay~",Decay_ar);

Decay_ar::Decay_ar(int argc,t_atom * argv)
{
    FLEXT_ADDMETHOD_(0,"decayTime",m_set);

    AtomList Args(argc,argv);

    decayTime = sc_getfloatarg(Args,0);

    AddOutSignal();

    m_y1 = 0.f;
}

void Decay_ar::m_signal(int n, t_sample *const *in, 
				t_sample *const *out)
{
    t_sample *nout = *out;
    t_sample *nin = *in;

    float b1 = m_b1;
    float y1 = m_y1;

    if (b1 == m_b1) 
    {
	if (b1 == 1.f) 
	{
	    for (int i = 0; i!= n;++i)
	    {
		float y0 = (*(nin)++); 
		(*(nout)++) = y1 = y0 + y1;
	    }
	    
	} 
	else if (b1 == 0.f) 
	{
	    for (int i = 0; i!= n;++i)
	    {
		float y0 = (*(nin)++); 
		(*(nout)++) = y1 = y0;
	    }
	} 
	else 
	{
	    for (int i = 0; i!= n;++i)
	    {
		float y0 = (*(nin)++); 
		(*(nout)++) = y1 = y0 + b1 * y1;
	    }
	}
    } 
    else 
    {
	float b1_slope = CALCSLOPE(m_b1, b1);
	if (b1 >= 0.f && m_b1 >= 0) 
	{
	    for (int i = 0; i!= n;++i) 
	    {
		float y0 = (*(nin)++); 
		(*(nout)++) = y1 = y0 + b1 * (y1 - y0);
		b1 += b1_slope;
	    }
	} 
	else if (b1 <= 0.f && m_b1 <= 0) 
	{
	    for (int i = 0; i!= n;++i) 
	    {
		float y0 = (*(nin)++); 
		(*(nout)++) = y1 = y0 + b1 * (y1 + y0);
		b1 += b1_slope;
	    }
	} 
	else 
	{
	    for (int i = 0; i!= n;++i) 
	    {
		float y0 = (*(nin)++); 
		(*(nout)++) = y1 = (1.f - fabs(b1)) * y0 + b1 * y1;
		b1 += b1_slope;
	    }
	}
    }
    m_y1 = zapgremlins(y1);
}
    
void Decay_ar::m_set(float f)
{
    decayTime = f;
    m_b1= f == 0.f ? 0.f : exp(log001 / (decayTime * Samplerate()));
}

void Decay_ar::m_dsp(int n, t_sample *const *in, t_sample *const *out)
{
    m_b1= decayTime == 0.f ? 0.f : exp(log001 / (decayTime * Samplerate()));
}

/* todo: does it make sense to implement a message-based Decay? 
   Probably not... */


/* ------------------------ Decay ------------------------------*/

// class Decay_kr
//     :public flext_base
// {
//     FLEXT_HEADER(Decay_kr,flext_base);

// public:
//     Decay_kr(int argc,t_atom * argv);

// protected:
//     void m_set(float f);
//     void m_perform(float f);
    
// private:
//     float m_b1;                       //leak
//     float m_y1;                       //z-1

//     FLEXT_CALLBACK_F(m_set);
//     FLEXT_CALLBACK_F(m_perform);
// };

// FLEXT_LIB_V("Decay",Decay_kr);

// Decay_kr::Decay_kr(int argc,t_atom * argv)
// {
//     AtomList Args(argc,argv);

//     m_b1 = sc_getfloatarg(Args,0);
//     m_y1 = 0.f;

    
//     AddInFloat();
//     AddOutFloat();

//     FLEXT_ADDMETHOD(0,m_perform);
//     FLEXT_ADDMETHOD_(0,"leak",m_set);
// }

// void Decay_kr::m_perform(float f)
// {
//     m_y1 = f + m_y1 * m_b1;
//     ToOutFloat(0,m_y1);
// }

// void Decay_kr::m_set(float f)
// {
//     m_b1=f;
// }