desc: Single Pole Recursive Lowpass/Highpass Filter

slider1:200<20,22000,1>Frequency (Hz)
slider2:0<0,1,1{lowpass,highpass}>Mode
slider3:0<-24,24,0.1>Output (dB)

in_pin:L in
in_pin:R in
out_pin:L out
out_pin:R out

@init
y0 = y1 = 0;

@slider
C = exp(-2*$pi*slider1/srate);
gain=10^(slider3/20);

@sample
slider2==1?(
spl0 -= y0 = spl0 + C*(y0 - spl0);
spl1 -= y1 = spl1 + C*(y1 - spl1);
):(
spl0 = y0 = spl0 + C*(y0 - spl0);
spl1 = y1 = spl1 + C*(y1 - spl1);
);

spl0*=gain;
spl1*=gain;
