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/*
ZynAddSubFX - a software synthesizer
LFO.C - LFO implementation
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 "LFO.h"
LFO::LFO(LFOParams *lfopars,REALTYPE basefreq){
if (lfopars->Pstretch==0) lfopars->Pstretch=1;
REALTYPE lfostretch=pow(basefreq/440.0,(lfopars->Pstretch-64.0)/63.0);//max 2x/octave
REALTYPE lfofreq=(pow(2,lfopars->Pfreq*10.0)-1.0)/12.0*lfostretch;
incx=fabs(lfofreq)*(REALTYPE)SOUND_BUFFER_SIZE/(REALTYPE)SAMPLE_RATE;
if (lfopars->Pcontinous==0){
if (lfopars->Pstartphase==0) x=RND;
else x=fmod((lfopars->Pstartphase-64.0)/127.0+1.0,1.0);
} else {
REALTYPE tmp=fmod(lfopars->time*incx,1.0);
x=fmod((lfopars->Pstartphase-64.0)/127.0+1.0+tmp,1.0);
};
//Limit the Frequency(or else...)
if (incx>0.49999999) incx=0.499999999;
lfornd=lfopars->Prandomness/127.0;
if (lfornd<0.0) lfornd=0.0; else if (lfornd>1.0) lfornd=1.0;
// lfofreqrnd=pow(lfopars->Pfreqrand/127.0,2.0)*2.0*4.0;
lfofreqrnd=pow(lfopars->Pfreqrand/127.0,2.0)*4.0;
switch (lfopars->fel){
case 1:lfointensity=lfopars->Pintensity/127.0;break;
case 2:lfointensity=lfopars->Pintensity/127.0*4.0;break;//in octave
default:lfointensity=pow(2,lfopars->Pintensity/127.0*11.0)-1.0;//in centi
x-=0.25;//chance the starting phase
break;
};
amp1=(1-lfornd)+lfornd*RND;
amp2=(1-lfornd)+lfornd*RND;
lfotype=lfopars->PLFOtype;
lfodelay=lfopars->Pdelay/127.0*4.0;//0..4 sec
incrnd=nextincrnd=1.0;
freqrndenabled=(lfopars->Pfreqrand!=0);
computenextincrnd();
computenextincrnd();//twice because I want incrnd & nextincrnd to be random
};
LFO::~LFO(){
};
/*
* LFO out
*/
REALTYPE LFO::lfoout(){
REALTYPE out;
switch (lfotype){
case 1: //LFO_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;
case 2: //LFO_SQUARE
if (x<0.5) out=-1;
else out=1;
break;
case 3: //LFO_RAMPUP
out=(x-0.5)*2.0;
break;
case 4: //LFO_RAMPDOWN
out=(0.5-x)*2.0;
break;
case 5: //LFO_EXP_DOWN 1
out=pow(0.05,x)*2.0-1.0;
break;
case 6: //LFO_EXP_DOWN 2
out=pow(0.001,x)*2.0-1.0;
break;
default:out=cos(x*2.0*PI);//LFO_SINE
};
if ((lfotype==0)||(lfotype==1)) out*=lfointensity*(amp1+x*(amp2-amp1));
else out*=lfointensity*amp2;
if (lfodelay<0.00001) {
if (freqrndenabled==0) x+=incx;
else {
float tmp=(incrnd*(1.0-x)+nextincrnd*x);
if (tmp>1.0) tmp=1.0;
else if (tmp<0.0) tmp=0.0;
x+=incx*tmp;
};
if (x>=1) {
x=fmod(x,1.0);
amp1=amp2;
amp2=(1-lfornd)+lfornd*RND;
computenextincrnd();
};
} else lfodelay-=(REALTYPE)SOUND_BUFFER_SIZE/(REALTYPE)SAMPLE_RATE;
return(out);
};
/*
* LFO out (for amplitude)
*/
REALTYPE LFO::amplfoout(){
REALTYPE out;
out=1.0-lfointensity+lfoout();
if (out<-1.0) out=-1.0;
else if (out>1.0) out=1.0;
return(out);
};
void LFO::computenextincrnd(){
if (freqrndenabled==0) return;
incrnd=nextincrnd;
nextincrnd=pow(0.5,lfofreqrnd)+RND*(pow(2.0,lfofreqrnd)-1.0);
};
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