/*
  ZynAddSubFX - a software synthesizer
 
  EffectLFO.C - Stereo LFO used by some effects
  Copyright (C) 2002-2005 Nasca Octavian Paul
  Author: Nasca Octavian Paul

  This program is free software; you can redistribute it and/or modify
  it under the terms of version 2 of the GNU General Public License 
  as published by the Free Software Foundation.

  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 (version 2) for more details.

  You should have received a copy of the GNU General Public License (version 2)
  along with this program; if not, write to the Free Software Foundation,
  Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA

*/

#include <stdlib.h>
#include <stdio.h>
#include <math.h>

#include "EffectLFO.h"


EffectLFO::EffectLFO(){
    xl=0.0;xr=0.0;
    Pfreq=40;
    Prandomness=0;
    PLFOtype=0;
    Pstereo=96;
    
    updateparams();

    ampl1=(1-lfornd)+lfornd*RND;
    ampl2=(1-lfornd)+lfornd*RND;
    ampr1=(1-lfornd)+lfornd*RND;
    ampr2=(1-lfornd)+lfornd*RND;
};

EffectLFO::~EffectLFO(){
};


/*
 * Update the changed parameters
 */
void EffectLFO::updateparams(){
    REALTYPE lfofreq=(pow(2,Pfreq/127.0*10.0)-1.0)*0.03;
    incx=fabs(lfofreq)*(REALTYPE)SOUND_BUFFER_SIZE/(REALTYPE)SAMPLE_RATE;
    if (incx>0.49999999) incx=0.499999999; //Limit the Frequency

    lfornd=Prandomness/127.0;
    if (lfornd<0.0) lfornd=0.0; else if (lfornd>1.0) lfornd=1.0;

    if (PLFOtype>1) PLFOtype=1;//this has to be updated if more lfo's are added
    lfotype=PLFOtype;

    xr=fmod(xl+(Pstereo-64.0)/127.0+1.0,1.0);
};


/*
 * Compute the shape of the LFO
 */
REALTYPE EffectLFO::getlfoshape(REALTYPE x){
    REALTYPE out;
    switch (lfotype){
	case 1: //EffectLFO_TRIANGLE
		if ((x>0.0)&&(x<0.25)) out=4.0*x;
		else if ((x>0.25)&&(x<0.75)) out=2-4*x;
		     else out=4.0*x-4.0;
		break;
	//more to be added here; also ::updateparams() need to be updated (to allow more lfotypes)
	default:out=cos(x*2*PI);//EffectLFO_SINE
    };
    return(out);
};

/*
 * LFO output
 */
void EffectLFO::effectlfoout(REALTYPE *outl,REALTYPE *outr){
    REALTYPE out;    
    
    out=getlfoshape(xl);
    if ((lfotype==0)||(lfotype==1)) out*=(ampl1+xl*(ampl2-ampl1));
    xl+=incx;
    if (xl>1.0) {
	xl-=1.0;
	ampl1=ampl2;
	ampl2=(1.0-lfornd)+lfornd*RND;
    };
    *outl=(out+1.0)*0.5;

    out=getlfoshape(xr);
    if ((lfotype==0)||(lfotype==1)) out*=(ampr1+xr*(ampr2-ampr1));
    xr+=incx;
    if (xr>1.0) {
	xr-=1.0;
	ampr1=ampr2;
	ampr2=(1.0-lfornd)+lfornd*RND;
    };
    *outr=(out+1.0)*0.5;
};