Linear smoother

lsmooth.dsp

import("stdfaust.lib");

// a linear smoother
lfsmooth(tau, flush, tgt) =
  ((+:(_,tgt):select2(flush))~_)~((tgt-_)<:(abs,(/(tau*ma.SR):(select2(sc)~_):abs),_):(min,_):copysign)
with {
  sc = (tgt!=tgt')|(tau!=tau');
  copysign(x,s) = abs(x)*select2(s<0.0,1.0,-1.0);
  //copysign = ffunction(float copysignf|copysign|copysignl(float,float),<math.h>,"");
};
lsmooth(tau) = lfsmooth(tau, 0);

process = lsmooth(t,x) with {
  x = hslider("[1] target",0.0,-1.0,1.0,0.001);
  t = hslider("[2] time",0.1,0.0,1.0,0.001);
};