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Diffstat (limited to 'modules/scrollgrid1D.c')
| -rw-r--r-- | modules/scrollgrid1D.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/modules/scrollgrid1D.c b/modules/scrollgrid1D.c new file mode 100644 index 0000000..bcac7fe --- /dev/null +++ b/modules/scrollgrid1D.c @@ -0,0 +1,220 @@ +/* + * 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 float _fixedpoint(float x, int n) +{ + int ix = (x + 0.5f); + if (ix < 0) ix = 0; + else if (ix >= n) ix = n-1; + return (float)ix; +} + +static inline float _sat(float x, float upper) +{ + float lower = -1.0f; + if (x < lower) x = lower; + else if (x > upper) x = upper; + return x; +} + +static t_int *scrollgrid1D_perform(t_int *w) +{ + + + t_float *freq = (float *)(w[3]); + t_float *t1 = (float *)(w[4]); + t_float *t2 = (float *)(w[5]); + t_float *order = (float *)(w[6]); + t_float *outx = (float *)(w[7]); + t_float *outy = (float *)(w[8]); + t_float *outz = (float *)(w[9]); + t_scrollgrid1Dctl *ctl = (t_scrollgrid1Dctl *)(w[1]); + t_int n = (t_int)(w[2]); + + t_int i; + t_float inv_sr = 1.0f /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; + t_int o; + t_float x,y,z; + + + for (i=0; i<n; i++){ + + /* get params */ + r1 = exp(1000.0f * inv_sr / (0.01f + fabs(*t1++))); + r2 = exp(-1000.0f * inv_sr / (0.01f + fabs(*t2++))); + f = *freq++; + o = (int)(*order++); + if (o < 2) o = 2; + pole[0] = r1 * cos(2.0f * M_PI * inv_sr * f); + pole[1] = r1 * sin(2.0f * M_PI * inv_sr * f); + + /* debug */ + //post("%f", r1); + + /* base transform + clipping to prevent blowup */ + x = _sat(0.5f * (state[0] - state[2]), (float)o); /* projection onto axis containing fixed */ + y = _sat(0.5f * state[1], 1.0f); /* the "pure" oscillation axis */ + z = _sat(0.5f * (state[0] + state[2]), 1.0f); /* orthogonal complement of x */ + + /* 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] = 2.0f * 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); + + +} + |