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authorPeter D'Hoye <peter.dhoye@gmail.com>2009-05-22 21:58:48 +0000
committerPeter D'Hoye <peter.dhoye@gmail.com>2009-05-22 21:58:48 +0000
commit513389b4c1bc8afe4b2dc9947c534bfeb105e3da (patch)
tree10e673b35651ac567fed2eda0c679c7ade64cbc6 /apps/plugins/pdbox/PDa/extra/bandpass.c
parent95fa7f6a2ef466444fbe3fe87efc6d5db6b77b36 (diff)
downloadrockbox-513389b4c1bc8afe4b2dc9947c534bfeb105e3da.tar.gz
rockbox-513389b4c1bc8afe4b2dc9947c534bfeb105e3da.zip
Add FS #10214. Initial commit of the original PDa code for the GSoC Pure Data plugin project of Wincent Balin. Stripped some non-sourcefiles and added a rockbox readme that needs a bit more info from Wincent. Is added to CATEGORIES and viewers, but not yet to SUBDIRS (ie doesn't build yet)
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21044 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'apps/plugins/pdbox/PDa/extra/bandpass.c')
-rw-r--r--apps/plugins/pdbox/PDa/extra/bandpass.c172
1 files changed, 172 insertions, 0 deletions
diff --git a/apps/plugins/pdbox/PDa/extra/bandpass.c b/apps/plugins/pdbox/PDa/extra/bandpass.c
new file mode 100644
index 0000000000..6de56d6174
--- /dev/null
+++ b/apps/plugins/pdbox/PDa/extra/bandpass.c
@@ -0,0 +1,172 @@
1
2/* (C) Guenter Geiger <geiger@epy.co.at> */
3
4
5/*
6
7 These filter coefficients computations are taken from
8 http://www.harmony-central.com/Computer/Programming/Audio-EQ-Cookbook.txt
9
10 written by Robert Bristow-Johnson
11
12*/
13
14#include "m_pd.h"
15#ifdef NT
16#pragma warning( disable : 4244 )
17#pragma warning( disable : 4305 )
18#endif
19#include <math.h>
20#include "filters.h"
21
22/* ------------------- bandpass ----------------------------*/
23
24static t_class *bandpass_class;
25
26void bandpass_bang(t_rbjfilter *x)
27{
28 t_atom at[5];
29 t_float omega = e_omega(x->x_freq,x->x_rate);
30 t_float alpha = e_alpha(x->x_bw* 0.01,omega);
31 t_float b1 = 0.;
32 t_float b0 = alpha;
33 t_float b2 = -alpha;
34 t_float a0 = 1 + alpha;
35 t_float a1 = -2.*cos(omega);
36 t_float a2 = 1 - alpha;
37
38/* post("bang %f %f %f",x->x_freq, x->x_gain, x->x_bw); */
39
40 if (!check_stability(-a1/a0,-a2/a0,b0/a0,b1/a0,b2/a0)) {
41 post("bandpass: filter unstable -> resetting");
42 a0=1.;a1=0.;a2=0.;
43 b0=1.;b1=0.;b2=0.;
44 }
45
46 SETFLOAT(at,-a1/a0);
47 SETFLOAT(at+1,-a2/a0);
48 SETFLOAT(at+2,b0/a0);
49 SETFLOAT(at+3,b1/a0);
50 SETFLOAT(at+4,b2/a0);
51
52 outlet_list(x->x_obj.ob_outlet,&s_list,5,at);
53}
54
55
56void bandpass_float(t_rbjfilter *x,t_floatarg f)
57{
58 x->x_freq = f;
59 bandpass_bang(x);
60}
61
62
63static void *bandpass_new(t_floatarg f,t_floatarg bw)
64{
65 t_rbjfilter *x = (t_rbjfilter *)pd_new(bandpass_class);
66
67 x->x_rate = 44100.0;
68 outlet_new(&x->x_obj,&s_float);
69/* floatinlet_new(&x->x_obj, &x->x_gain); */
70 floatinlet_new(&x->x_obj, &x->x_bw);
71 if (f > 0.) x->x_freq = f;
72 if (bw > 0.) x->x_bw = bw;
73 return (x);
74}
75
76
77void bandpass_setup(void)
78{
79 bandpass_class = class_new(gensym("bandpass"), (t_newmethod)bandpass_new, 0,
80 sizeof(t_rbjfilter), 0,A_DEFFLOAT,A_DEFFLOAT,0);
81 class_addbang(bandpass_class,bandpass_bang);
82 class_addfloat(bandpass_class,bandpass_float);
83}
84
85
86
87
88/* (C) Guenter Geiger <geiger@epy.co.at> */
89
90
91/*
92
93 These filter coefficients computations are taken from
94 http://www.harmony-central.com/Computer/Programming/Audio-EQ-Cookbook.txt
95
96 written by Robert Bristow-Johnson
97
98*/
99
100#include "m_pd.h"
101#ifdef NT
102#pragma warning( disable : 4244 )
103#pragma warning( disable : 4305 )
104#endif
105#include <math.h>
106#include "filters.h"
107
108/* ------------------- bandpass ----------------------------*/
109
110static t_class *bandpass_class;
111
112void bandpass_bang(t_rbjfilter *x)
113{
114 t_atom at[5];
115 t_float omega = e_omega(x->x_freq,x->x_rate);
116 t_float alpha = e_alpha(x->x_bw* 0.01,omega);
117 t_float b1 = 0.;
118 t_float b0 = alpha;
119 t_float b2 = -alpha;
120 t_float a0 = 1 + alpha;
121 t_float a1 = -2.*cos(omega);
122 t_float a2 = 1 - alpha;
123
124/* post("bang %f %f %f",x->x_freq, x->x_gain, x->x_bw); */
125
126 if (!check_stability(-a1/a0,-a2/a0,b0/a0,b1/a0,b2/a0)) {
127 post("bandpass: filter unstable -> resetting");
128 a0=1.;a1=0.;a2=0.;
129 b0=1.;b1=0.;b2=0.;
130 }
131
132 SETFLOAT(at,-a1/a0);
133 SETFLOAT(at+1,-a2/a0);
134 SETFLOAT(at+2,b0/a0);
135 SETFLOAT(at+3,b1/a0);
136 SETFLOAT(at+4,b2/a0);
137
138 outlet_list(x->x_obj.ob_outlet,&s_list,5,at);
139}
140
141
142void bandpass_float(t_rbjfilter *x,t_floatarg f)
143{
144 x->x_freq = f;
145 bandpass_bang(x);
146}
147
148
149static void *bandpass_new(t_floatarg f,t_floatarg bw)
150{
151 t_rbjfilter *x = (t_rbjfilter *)pd_new(bandpass_class);
152
153 x->x_rate = 44100.0;
154 outlet_new(&x->x_obj,&s_float);
155/* floatinlet_new(&x->x_obj, &x->x_gain); */
156 floatinlet_new(&x->x_obj, &x->x_bw);
157 if (f > 0.) x->x_freq = f;
158 if (bw > 0.) x->x_bw = bw;
159 return (x);
160}
161
162
163void bandpass_setup(void)
164{
165 bandpass_class = class_new(gensym("bandpass"), (t_newmethod)bandpass_new, 0,
166 sizeof(t_rbjfilter), 0,A_DEFFLOAT,A_DEFFLOAT,0);
167 class_addbang(bandpass_class,bandpass_bang);
168 class_addfloat(bandpass_class,bandpass_float);
169}
170
171
172
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