1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
/*
* cheby.c - chebyshev polynomial evaluation
* Copyright (c) 2000-2003 by Tom Schouten
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "m_pd.h"
#include <math.h>
#define MAX_ORDER 1024
#define DEFAULT_ORDER 4
typedef struct chebyctl
{
t_float c_gain[MAX_ORDER];
t_int c_order;
} t_chebyctl;
typedef struct cheby
{
t_object x_obj;
t_float x_f;
t_chebyctl x_ctl;
} t_cheby;
static void cheby_bang(t_cheby *x)
{
}
static void cheby_coef(t_cheby *x, t_floatarg coef, t_floatarg f)
{
int i = (int)coef;
if ((i > 0) && (i < x->x_ctl.c_order + 1)){
x->x_ctl.c_gain[i-1] = f;
/* post("cheby: harmonic %d set to %f", i, f); */
}
}
static t_int *cheby_perform(t_int *w)
{
t_float *in = (float *)(w[3]);
t_float *out = (float *)(w[4]);
t_chebyctl *ctl = (t_chebyctl *)(w[1]);
t_float *gain = ctl->c_gain;
t_int i;
t_int n = (t_int)(w[2]), k;
t_float x,y,t1,t2,t,acc;
for (i = 0; i < n; i++)
{
x = *in++;
gain = ctl->c_gain;
t2 = 1; /* T_0 */
t1 = x; /* T_1 */
acc = *gain++ * x; /* a_1 T_1 */
for (k=2; k<=ctl->c_order; k++){
t = 2*x*t1 - t2; /* T_k = 2 x T_{k-1} - T_{k-2} */
acc += *gain++ * t; /* a_k T_k */
t2 = t1;
t1 = t;
}
*out++ = acc;
}
return (w+5);
}
static void cheby_dsp(t_cheby *x, t_signal **sp)
{
dsp_add(cheby_perform, 4, &x->x_ctl, sp[0]->s_n,
sp[0]->s_vec, sp[1]->s_vec);
}
static void cheby_free(void)
{
}
t_class *cheby_class;
static void *cheby_new(t_floatarg order_f)
{
int i;
int order = (int)order_f;
t_cheby *x = (t_cheby *)pd_new(cheby_class);
outlet_new(&x->x_obj, gensym("signal"));
if (order < 1) order = DEFAULT_ORDER; /* default */
if (order > MAX_ORDER) order = MAX_ORDER; /* maximum */
//post("cheby: order = %d", order);
x->x_ctl.c_order = order;
cheby_coef(x, 1, 1);
for (i=2; i<order+1; i++){
cheby_coef(x, 0, i);
}
return (void *)x;
}
void cheby_tilde_setup(void)
{
//post("cheby~ v0.1");
cheby_class = class_new(gensym("cheby~"), (t_newmethod)cheby_new,
(t_method)cheby_free, sizeof(t_cheby), 0, A_DEFFLOAT, 0);
CLASS_MAINSIGNALIN(cheby_class, t_cheby, x_f);
class_addmethod(cheby_class, (t_method)cheby_bang, gensym("bang"), 0);
class_addmethod(cheby_class, (t_method)cheby_dsp, gensym("dsp"), 0);
class_addmethod(cheby_class, (t_method)cheby_coef, gensym("coef"),
A_DEFFLOAT, A_DEFFLOAT, 0);
}
|
