diff options
Diffstat (limited to 'filters/lowpass.c')
-rwxr-xr-x | filters/lowpass.c | 178 |
1 files changed, 89 insertions, 89 deletions
diff --git a/filters/lowpass.c b/filters/lowpass.c index 4e1b2b9..7155044 100755 --- a/filters/lowpass.c +++ b/filters/lowpass.c @@ -1,89 +1,89 @@ -/* (C) Guenter Geiger <geiger@epy.co.at> */
-
-
-/*
-
- These filter coefficients computations are taken from
- http://www.harmony-central.com/Computer/Programming/Audio-EQ-Cookbook.txt
-
- written by Robert Bristow-Johnson
-
-*/
-
-#include <m_pd.h>
-#ifdef NT
-#pragma warning( disable : 4244 )
-#pragma warning( disable : 4305 )
-#endif
-#include <math.h>
-#include "filters.h"
-
-
-
-/* ------------------- lowpass ----------------------------*/
-
-static t_class *lowpass_class;
-
-void lowpass_bang(t_rbjfilter *x)
-{
- t_atom at[5];
- t_float omega = e_omega(x->x_freq,x->x_rate);
- t_float alpha = e_alpha(x->x_bw*0.01,omega);
- t_float b1 = 1 - cos(omega);
- t_float b0 = b1/2.;
- t_float b2 = b0;
- t_float a0 = 1 + alpha;
- t_float a1 = -2.*cos(omega);
- t_float a2 = 1 - alpha;
-
-/* post("bang %f %f %f",x->x_freq, x->x_gain, x->x_bw); */
-
- if (!check_stability(-a1/a0,-a2/a0,b0/a0,b1/a0,b2/a0)) {
- post("lowpass: filter unstable -> resetting");
- a0=1.;a1=0.;a2=0.;
- b0=1.;b1=0.;b2=0.;
- }
-
- SETFLOAT(at,-a1/a0);
- SETFLOAT(at+1,-a2/a0);
- SETFLOAT(at+2,b0/a0);
- SETFLOAT(at+3,b1/a0);
- SETFLOAT(at+4,b2/a0);
-
- outlet_list(x->x_obj.ob_outlet,&s_list,5,at);
-}
-
-
-void lowpass_float(t_rbjfilter *x,t_floatarg f)
-{
- x->x_freq = f;
- lowpass_bang(x);
-}
-
-
-static void *lowpass_new(t_floatarg f,t_floatarg bw)
-{
- t_rbjfilter *x = (t_rbjfilter *)pd_new(lowpass_class);
-
- x->x_rate = 44100.0;
- outlet_new(&x->x_obj,&s_float);
-/* floatinlet_new(&x->x_obj, &x->x_gain); */
- floatinlet_new(&x->x_obj, &x->x_bw);
-
- if (f > 0.) x->x_freq = f;
- if (bw > 0.) x->x_bw = bw;
- return (x);
-}
-
-
-void lowpass_setup(void)
-{
- lowpass_class = class_new(gensym("lowpass"), (t_newmethod)lowpass_new, 0,
- sizeof(t_rbjfilter), 0,A_DEFFLOAT,A_DEFFLOAT,0);
- class_addbang(lowpass_class,lowpass_bang);
- class_addfloat(lowpass_class,lowpass_float);
-}
-
-
-
-
+/* (C) Guenter Geiger <geiger@epy.co.at> */ + + +/* + + These filter coefficients computations are taken from + http://www.harmony-central.com/Computer/Programming/Audio-EQ-Cookbook.txt + + written by Robert Bristow-Johnson + +*/ + +#include <m_pd.h> +#ifdef _MSC_VER +#pragma warning( disable : 4244 ) +#pragma warning( disable : 4305 ) +#endif +#include <math.h> +#include "filters.h" + + + +/* ------------------- lowpass ----------------------------*/ + +static t_class *lowpass_class; + +void lowpass_bang(t_rbjfilter *x) +{ + t_atom at[5]; + t_float omega = e_omega(x->x_freq,x->x_rate); + t_float alpha = e_alpha(x->x_bw*0.01,omega); + t_float b1 = 1 - cos(omega); + t_float b0 = b1/2.; + t_float b2 = b0; + t_float a0 = 1 + alpha; + t_float a1 = -2.*cos(omega); + t_float a2 = 1 - alpha; + +/* post("bang %f %f %f",x->x_freq, x->x_gain, x->x_bw); */ + + if (!check_stability(-a1/a0,-a2/a0,b0/a0,b1/a0,b2/a0)) { + post("lowpass: filter unstable -> resetting"); + a0=1.;a1=0.;a2=0.; + b0=1.;b1=0.;b2=0.; + } + + SETFLOAT(at,-a1/a0); + SETFLOAT(at+1,-a2/a0); + SETFLOAT(at+2,b0/a0); + SETFLOAT(at+3,b1/a0); + SETFLOAT(at+4,b2/a0); + + outlet_list(x->x_obj.ob_outlet,&s_list,5,at); +} + + +void lowpass_float(t_rbjfilter *x,t_floatarg f) +{ + x->x_freq = f; + lowpass_bang(x); +} + + +static void *lowpass_new(t_floatarg f,t_floatarg bw) +{ + t_rbjfilter *x = (t_rbjfilter *)pd_new(lowpass_class); + + x->x_rate = 44100.0; + outlet_new(&x->x_obj,&s_float); +/* floatinlet_new(&x->x_obj, &x->x_gain); */ + floatinlet_new(&x->x_obj, &x->x_bw); + + if (f > 0.) x->x_freq = f; + if (bw > 0.) x->x_bw = bw; + return (x); +} + + +void lowpass_setup(void) +{ + lowpass_class = class_new(gensym("lowpass"), (t_newmethod)lowpass_new, 0, + sizeof(t_rbjfilter), 0,A_DEFFLOAT,A_DEFFLOAT,0); + class_addbang(lowpass_class,lowpass_bang); + class_addfloat(lowpass_class,lowpass_float); +} + + + + |