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/*
* scrollgrid1D.c - 1D scroll grid attractor
* 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.
*/
/* 1D scroll grid attractor
for more information see:
Yalcin M., Ozoguz S., Suykens J.A.K., Vandewalle J., ``Families of
Scroll Grid Attractors'', International Journal of Bifurcation and
Chaos, vol. 12, no. 1, Jan. 2002, pp. 23-41.
this file implements a digital variant of the method introduced in
the paper, so that it can be used as a parametrizable, bounded
chatotic oscillator. in short it is a switched linear system,
with some added hard limiting to convert unstable oscillations
into stable ones.
*/
#include "m_pd.h"
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "filters.h"
typedef struct scrollgrid1Dctl
{
t_float c_x, c_y, c_z; /* state */
} t_scrollgrid1Dctl;
typedef struct scrollgrid1D
{
t_object x_obj;
t_float x_f;
t_scrollgrid1Dctl x_ctl;
} t_scrollgrid1D;
static inline t_float _fixedpoint(t_float x, int n)
{
int ix = (x + 0.5);
if (ix < 0) ix = 0;
else if (ix >= n) ix = n-1;
return (t_float)ix;
}
static inline t_float _sat(t_float x, t_float upper)
{
t_float lower = -1.0;
if (x < lower) x = lower;
else if (x > upper) x = upper;
return x;
}
static t_int *scrollgrid1D_perform(t_int *w)
{
t_float *freq = (t_float *)(w[3]);
t_float *t1 = (t_float *)(w[4]);
t_float *t2 = (t_float *)(w[5]);
t_float *order = (t_float *)(w[6]);
t_float *outx = (t_float *)(w[7]);
t_float *outy = (t_float *)(w[8]);
t_float *outz = (t_float *)(w[9]);
t_scrollgrid1Dctl *ctl = (t_scrollgrid1Dctl *)(w[1]);
int n = (int)(w[2]);
int i;
t_float inv_sr = 1.0 /sys_getsr();
t_float state[3] = {ctl->c_x, ctl->c_y, ctl->c_z};
t_float c,f;
t_float pole[2], r1, r2;
int o;
t_float x,y,z;
for (i=0; i<n; i++){
/* get params */
r1 = exp(1000.0 * inv_sr / (0.01 + fabs(*t1++)));
r2 = exp(-1000.0 * inv_sr / (0.01 + fabs(*t2++)));
f = *freq++;
o = (int)(*order++);
if (o < 2) o = 2;
pole[0] = r1 * cos(2.0 * M_PI * inv_sr * f);
pole[1] = r1 * sin(2.0 * M_PI * inv_sr * f);
/* debug */
//post("%f", r1);
/* base transform + clipping to prevent blowup */
/* projection onto axis containing fixed */
x = _sat(0.5 * (state[0] - state[2]), (t_float)o);
/* the "pure" oscillation axis */
y = _sat(0.5 * state[1], 1.0);
/* orthogonal complement of x */
z = _sat(0.5 * (state[0] + state[2]), 1.0);
/* output */
*outx++ = x;
*outy++ = y;
*outz++ = z;
/* calculate fixed point location (c, 0, -c) */
c = _fixedpoint(x, o);
/* inverse base transform */
state[0] = x + z;
state[1] = 2.0 * y;
state[2] = -x + z;
/* update transformed linear system around unstable fixed point */
state[0] -= c;
state[2] += c;
vcmul2(state, pole);
state[2] *= r2;
state[0] += c;
state[2] -= c;
}
ctl->c_x = state[0];
ctl->c_y = state[1];
ctl->c_z = state[2];
return (w+10);
}
static void scrollgrid1D_dsp(t_scrollgrid1D *x, t_signal **sp)
{
int n = sp[0]->s_n;
int k;
dsp_add(scrollgrid1D_perform,
9,
&x->x_ctl,
sp[0]->s_n,
sp[0]->s_vec,
sp[1]->s_vec,
sp[2]->s_vec,
sp[3]->s_vec,
sp[4]->s_vec,
sp[5]->s_vec,
sp[6]->s_vec);
}
static void scrollgrid1D_free(t_scrollgrid1D *x)
{
}
static void scrollgrid1D_reset(t_scrollgrid1D *x)
{
x->x_ctl.c_x = 1;
x->x_ctl.c_y = 1;
x->x_ctl.c_z = 1;
}
t_class *scrollgrid1D_class;
static void *scrollgrid1D_new(t_floatarg algotype)
{
t_scrollgrid1D *x = (t_scrollgrid1D *)pd_new(scrollgrid1D_class);
/* ins */
inlet_new(&x->x_obj, &x->x_obj.ob_pd, gensym("signal"), gensym("signal"));
inlet_new(&x->x_obj, &x->x_obj.ob_pd, gensym("signal"), gensym("signal"));
inlet_new(&x->x_obj, &x->x_obj.ob_pd, gensym("signal"), gensym("signal"));
/* outs */
outlet_new(&x->x_obj, gensym("signal"));
outlet_new(&x->x_obj, gensym("signal"));
outlet_new(&x->x_obj, gensym("signal"));
/* init data */
scrollgrid1D_reset(x);
return (void *)x;
}
void scrollgrid1D_tilde_setup(void)
{
//post("scrollgrid1D~ v0.1");
scrollgrid1D_class = class_new(gensym("scrollgrid1D~"),
(t_newmethod)scrollgrid1D_new,
(t_method)scrollgrid1D_free, sizeof(t_scrollgrid1D), 0, A_DEFFLOAT, 0);
CLASS_MAINSIGNALIN(scrollgrid1D_class, t_scrollgrid1D, x_f);
class_addmethod(scrollgrid1D_class, (t_method)scrollgrid1D_dsp,
gensym("dsp"), 0);
class_addmethod(scrollgrid1D_class, (t_method)scrollgrid1D_reset,
gensym("reset"), 0);
}
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