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authorPeter D'Hoye <peter.dhoye@gmail.com>2009-05-24 21:28:16 +0000
committerPeter D'Hoye <peter.dhoye@gmail.com>2009-05-24 21:28:16 +0000
commit526b5580dabbfed7cfe5439dc3a90ec727f563c2 (patch)
tree22b1af92348785daad16714ee5e2b633017e0e48 /apps/plugins/pdbox/PDa/extra/lowpass.c
parent4f2dfcc01b260d946044ef2b6af5fe36cb772c8d (diff)
downloadrockbox-526b5580dabbfed7cfe5439dc3a90ec727f563c2.tar.gz
rockbox-526b5580dabbfed7cfe5439dc3a90ec727f563c2.zip
Cut the files in half and it might work better (note to self: check your tree is really clean before patching)
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21070 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'apps/plugins/pdbox/PDa/extra/lowpass.c')
-rw-r--r--apps/plugins/pdbox/PDa/extra/lowpass.c93
1 files changed, 1 insertions, 92 deletions
diff --git a/apps/plugins/pdbox/PDa/extra/lowpass.c b/apps/plugins/pdbox/PDa/extra/lowpass.c
index c242aff0a8..251b7175f3 100644
--- a/apps/plugins/pdbox/PDa/extra/lowpass.c
+++ b/apps/plugins/pdbox/PDa/extra/lowpass.c
@@ -84,95 +84,4 @@ void lowpass_setup(void)
84 class_addfloat(lowpass_class,lowpass_float); 84 class_addfloat(lowpass_class,lowpass_float);
85} 85}
86 86
87 87
88
89
90/* (C) Guenter Geiger <geiger@epy.co.at> */
91
92
93/*
94
95 These filter coefficients computations are taken from
96 http://www.harmony-central.com/Computer/Programming/Audio-EQ-Cookbook.txt
97
98 written by Robert Bristow-Johnson
99
100*/
101
102#include "m_pd.h"
103#ifdef NT
104#pragma warning( disable : 4244 )
105#pragma warning( disable : 4305 )
106#endif
107#include <math.h>
108#include "filters.h"
109
110
111
112/* ------------------- lowpass ----------------------------*/
113
114static t_class *lowpass_class;
115
116void lowpass_bang(t_rbjfilter *x)
117{
118 t_atom at[5];
119 t_float omega = e_omega(x->x_freq,x->x_rate);
120 t_float alpha = e_alpha(x->x_bw*0.01,omega);
121 t_float b1 = 1 - cos(omega);
122 t_float b0 = b1/2.;
123 t_float b2 = b0;
124 t_float a0 = 1 + alpha;
125 t_float a1 = -2.*cos(omega);
126 t_float a2 = 1 - alpha;
127
128/* post("bang %f %f %f",x->x_freq, x->x_gain, x->x_bw); */
129
130 if (!check_stability(-a1/a0,-a2/a0,b0/a0,b1/a0,b2/a0)) {
131 post("lowpass: filter unstable -> resetting");
132 a0=1.;a1=0.;a2=0.;
133 b0=1.;b1=0.;b2=0.;
134 }
135
136 SETFLOAT(at,-a1/a0);
137 SETFLOAT(at+1,-a2/a0);
138 SETFLOAT(at+2,b0/a0);
139 SETFLOAT(at+3,b1/a0);
140 SETFLOAT(at+4,b2/a0);
141
142 outlet_list(x->x_obj.ob_outlet,&s_list,5,at);
143}
144
145
146void lowpass_float(t_rbjfilter *x,t_floatarg f)
147{
148 x->x_freq = f;
149 lowpass_bang(x);
150}
151
152
153static void *lowpass_new(t_floatarg f,t_floatarg bw)
154{
155 t_rbjfilter *x = (t_rbjfilter *)pd_new(lowpass_class);
156
157 x->x_rate = 44100.0;
158 outlet_new(&x->x_obj,&s_float);
159/* floatinlet_new(&x->x_obj, &x->x_gain); */
160 floatinlet_new(&x->x_obj, &x->x_bw);
161
162 if (f > 0.) x->x_freq = f;
163 if (bw > 0.) x->x_bw = bw;
164 return (x);
165}
166
167
168void lowpass_setup(void)
169{
170 lowpass_class = class_new(gensym("lowpass"), (t_newmethod)lowpass_new, 0,
171 sizeof(t_rbjfilter), 0,A_DEFFLOAT,A_DEFFLOAT,0);
172 class_addbang(lowpass_class,lowpass_bang);
173 class_addfloat(lowpass_class,lowpass_float);
174}
175
176
177
178