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/*
* lattice.c - a lattice filter for pd
* 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 MAXORDER 1024
#define MAXREFCO 0.9999
typedef struct latticesegment
{
t_float delay; // delay element
t_float rc; // reflection coefficient
} t_latticesegment;
typedef struct latticectl
{
t_latticesegment c_segment[MAXORDER]; // array of lattice segment data
t_int c_segments;
} t_latticectl;
typedef struct lattice
{
t_object x_obj;
t_float x_f;
t_latticectl x_ctl;
} t_lattice;
static t_int *lattice_perform(t_int *w)
{
t_float *in = (t_float *)(w[3]);
t_float *out = (t_float *)(w[4]);
t_latticectl *ctl = (t_latticectl *)(w[1]);
t_int i,j;
t_int n = (t_int)(w[2]);
t_float x,rc,d;
t_latticesegment* seg = ctl->c_segment;
t_int segments = ctl->c_segments;
for (i=0; i<n; i++)
{
x = *in++;
// section 0
rc = seg[0].rc;
x += seg[0].delay * rc;
// section 1 to segments-1
for (j=1; j < segments; j++)
{
rc = seg[j].rc;
d = seg[j].delay;
x += d * rc;
seg[j-1].delay = d - rc * x;
}
// stub
seg[segments-1].delay = x;
*out++ = x;
}
return (w+5);
}
static void lattice_dsp(t_lattice *x, t_signal **sp)
{
dsp_add(lattice_perform, 4, &x->x_ctl, (t_int)sp[0]->s_n,
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sp[0]->s_vec, sp[1]->s_vec);
}
static void lattice_free(void)
{
}
t_class *lattice_class;
static void lattice_rc(t_lattice *x, t_float segment, t_float refco)
{
t_int seg = (t_float)segment;
if ((seg >= 0) && (seg < x->x_ctl.c_segments)){
if (refco >= MAXREFCO) refco = MAXREFCO;
if (refco <= -MAXREFCO) refco = -MAXREFCO;
x->x_ctl.c_segment[seg].rc = refco;
}
}
static void lattice_reset(t_lattice *x)
{
t_float* buf = (t_float *)x->x_ctl.c_segment;
t_int n = x->x_ctl.c_segments;
t_int i;
for (i=0; i<n; i++) buf[i]=0;
}
static void *lattice_new(t_floatarg segments)
{
t_lattice *x = (t_lattice *)pd_new(lattice_class);
t_int seg = (t_int)segments;
outlet_new(&x->x_obj, gensym("signal"));
if (seg < 1) seg = 1;
if (seg > MAXORDER) seg = MAXORDER;
x->x_ctl.c_segments = seg;
lattice_reset(x);
return (void *)x;
}
void lattice_tilde_setup(void)
{
//post("lattice~ v0.1");
lattice_class = class_new(gensym("lattice~"), (t_newmethod)lattice_new,
(t_method)lattice_free, sizeof(t_lattice), 0, A_DEFFLOAT, 0);
CLASS_MAINSIGNALIN(lattice_class, t_lattice, x_f);
class_addmethod(lattice_class, (t_method)lattice_dsp, gensym("dsp"),
A_CANT, 0);
class_addmethod(lattice_class, (t_method)lattice_reset, gensym("reset"), 0);
class_addmethod(lattice_class, (t_method)lattice_rc,
gensym("rc"), A_FLOAT, A_FLOAT, 0);
}