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/*
* window.c - window generation abstraction
* 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>
#include <stdlib.h>
static t_class *window_class;
typedef struct _window
{
t_object x_obj;
t_float x_f;
t_float *x_window;
t_int x_size;
t_symbol *x_type;
t_float x_typearg;
} t_window;
static t_int *window_perform(t_int *w)
{
t_window *x = (t_window *)(w[1]);
t_float *in = (t_float *)(w[2]);
t_float *out = (t_float *)(w[3]);
t_float *window = x->x_window;
int n = (int)(w[4]);
while (n--)
{
*out++ = (*in++) * (*window++);
}
return (w+5);
}
static void window_size(t_window *x, t_int n)
{
if (x->x_size != n){
if (x->x_window) free(x->x_window);
x->x_window = malloc(sizeof(float)*n);
x->x_size = n;
}
}
static void window_type(t_window *x, t_symbol *s, t_float f)
{
int i;
float a = 0;
float a_inc = 2 * M_PI / (float)(x->x_size);
if (!s) s = gensym("hamming");
if (s == gensym("hamming")){
for (i=0; i<x->x_size; i++){
float c = cos(a);
x->x_window[i] = (0.54 - 0.46 * c);
a += a_inc;
}
}
else if (s == gensym("hann")){
for (i=0; i<x->x_size; i++){
float c = cos(a);
x->x_window[i] = (0.5 - 0.5 * c);
a += a_inc;
}
}
else if (s == gensym("hann/hamming")){
for (i=0; i<x->x_size; i++) {
float c = cos(a);
x->x_window[i] = (0.5 - 0.5 * c) / (0.54 - 0.46 * c);
a += a_inc;
}
}
else if (s == gensym("bfft_pink")){
x->x_window[0] = 1.0f; //DC
x->x_window[1] = 1.0f / sqrt((double)(x->x_size>>1)); //NY
for (i=2; i<x->x_size; i+=2) {
double freq = (double)(i>>1);
float amp = sqrt(1.0 / freq);
x->x_window[i] = amp;
x->x_window[i+1] = amp;
}
}
else if (s == gensym("bfft_blue")){
x->x_window[0] = 1.0f; //DC
x->x_window[1] = sqrt((double)(x->x_size>>1)); //NY
for (i=2; i<x->x_size; i+=2) {
double freq = (double)(i>>1);
float amp = sqrt(freq);
x->x_window[i] = amp;
x->x_window[i+1] = amp;
}
}
else if (s == gensym("bfft_db/octave")){
float power = f/6.0;
x->x_window[0] = 1.0f; //DC
x->x_window[1] = pow((double)(x->x_size>>1), power); //NY
for (i=2; i<x->x_size; i+=2) {
double freq = (double)(i>>1);
float amp = pow(freq, power);
x->x_window[i] = amp;
x->x_window[i+1] = amp;
}
}
/* default is no window */
else{
post("bwin~: unknown window type, using rectangular");
for (i=0; i<x->x_size; i++) x->x_window[i] = 1.0f;
}
x->x_type = s;
x->x_typearg = f;
}
static void window_dsp(t_window *x, t_signal **sp)
{
int n = sp[0]->s_n;
if (x->x_size != n){
window_size(x, n);
window_type(x, x->x_type, x->x_typearg);
}
dsp_add(window_perform, 4, x, sp[0]->s_vec, sp[1]->s_vec, n);
}
static void window_free(t_window *x)
{
free(x->x_window);
}
static void *window_new(t_symbol *s)
{
t_window *x = (t_window *)pd_new(window_class);
outlet_new(&x->x_obj, &s_signal);
x->x_window = 0;
window_size(x, 64);
window_type(x, s, 0);
return (x);
}
void window_tilde_setup(void)
{
window_class = class_new(gensym("bwin~"), (t_newmethod)window_new, (t_method)window_free,
sizeof(t_window), 0, A_DEFSYMBOL, A_NULL);
CLASS_MAINSIGNALIN(window_class, t_window, x_f);
class_addmethod(window_class, (t_method)window_dsp, gensym("dsp"), A_NULL);
class_addmethod(window_class, (t_method)window_type, gensym("type"), A_SYMBOL, A_DEFFLOAT, A_NULL);
}
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