diff options
Diffstat (limited to 'reson.c')
| -rw-r--r-- | reson.c | 156 |
1 files changed, 156 insertions, 0 deletions
@@ -0,0 +1,156 @@ +/* + * Copyright (c) 1997-1999 Mark Danks. + * For information on usage and redistribution, and for a DISCLAIMER OF ALL + * WARRANTIES, see the file, "GEM.LICENSE.TERMS" in this distribution. + */ + +/* Original code by Miller Puckette */ +/* a non-interpolating reson filter, not very carefully coded... */ +/* 11/29/94 modified to do interpolation - M. Danks */ + +#include "m_pd.h" + +#include <stdlib.h> + +#define BUFSIZE 4096 + +typedef struct resonctl +{ + float c_freq; + float c_samprate; + float c_feedback; + int c_delayinsamps; + float c_fraction; + int c_phase; + float *c_buf; +} t_resonctl; + +typedef struct sigreson +{ + t_object x_obj; /* header */ + t_resonctl *x_ctl; /* pointer to state */ + t_resonctl x_cspace; /* garage for state when not in a chain */ +} t_sigreson; + +/* the DSP routine -- called for every n samples of input */ +static t_int *cu_reson(t_int *w) +{ + t_float *in1 = (t_float *)(w[1]); + t_float *in2 = (t_float *)(w[2]); + t_float *out = (t_float *)(w[3]); + t_resonctl *x = (t_resonctl *)(w[4]); + int n = (int)(w[5]); + long i; + int writephase = x->c_phase; + for (i = 0; i < n; i++) + { + /* note two tricks: 1. input is read before output + * is written, because the routine might be called + * in-place; + * 2 - a seed of 1E-20 is thrown in to avoid floating + * underflow which slows the calculation down. + */ + int readphase, phase, delayinsamps; + float fraction, f, g, freq, freqtemp; + + float ftemp; + + freq = *in2++; + freqtemp = (freq < 1 ? 1 : freq); + + ftemp = x->c_samprate/freqtemp; + if (ftemp >= BUFSIZE-1) + ftemp = BUFSIZE - 1.f; + else if (ftemp < 1.0) + ftemp = 1.f; + delayinsamps = (int)ftemp; + fraction = ftemp - delayinsamps; + + readphase = writephase - delayinsamps; + phase = readphase & (BUFSIZE-1); + f = x->c_buf[phase] + fraction * + (x->c_buf[(phase-1)& (BUFSIZE-1)] - x->c_buf[phase]); + g = *in1++; + *out++ = x->c_buf[(writephase++) & (BUFSIZE-1)] = + g + x->c_feedback * f + 1E-20f; + } + x->c_phase = writephase & (BUFSIZE-1); + return (w+6); +} + +/* sets the reson frequency */ + +void sigreson_float(t_sigreson *x, t_floatarg f) +{ + float ftemp; + + x->x_ctl->c_freq = (f < 1 ? 1 : f); + + ftemp = x->x_ctl->c_samprate/x->x_ctl->c_freq; + if (ftemp >= BUFSIZE - 1) + ftemp = BUFSIZE - 1.f; + else if (ftemp < 1.0) + ftemp = 1.f; + x->x_ctl->c_delayinsamps = (int)ftemp; + x->x_ctl->c_fraction = ftemp - x->x_ctl->c_delayinsamps; +} + +/* routine which FTS calls to put you on the DSP chain or take you off. */ + +static void sigreson_dsp(t_sigreson *x, t_signal **sp) +{ + x->x_ctl->c_samprate = sp[0]->s_sr; + sigreson_float(x, x->x_ctl->c_freq); + dsp_add(cu_reson, 5, sp[0]->s_vec, sp[1]->s_vec, sp[2]->s_vec, + x->x_ctl, sp[0]->s_n); +} + +static void sigreson_ft1(t_sigreson *x, t_floatarg f) /* sets feedback */ +{ + if (f > .99999) f = .99999f; + else if (f < -.99999) f = -.99999f; + x->x_ctl->c_feedback = (float)f; +} + +static void sigreson_ff(t_sigreson *x) /* cleanup on free */ +{ + free(x->x_ctl->c_buf); +} + +static t_class *sigreson_class; + +void *sigreson_new(t_floatarg f, t_floatarg g) +{ + t_sigreson *x = (t_sigreson *)pd_new(sigreson_class); + outlet_new(&x->x_obj, &s_signal); + + /* things in "cspace" are things you'll actually use at DSP time */ + x->x_cspace.c_phase = 0; + if (!(x->x_cspace.c_buf = (float *)malloc(BUFSIZE * sizeof(float)))) + { + error("buffer alloc failed"); + return (0); + } + x->x_cspace.c_samprate = 44100.f; /* just a plausible default */ + + /* control block is in the garage at startup */ + x->x_ctl = &x->x_cspace; + sigreson_float(x, (t_float)f); /* setup params */ + sigreson_ft1(x, g); + /* make a "float" inlet */ + inlet_new(&x->x_obj, &x->x_obj.ob_pd, &s_signal, &s_signal); + inlet_new(&x->x_obj, &x->x_obj.ob_pd, &s_float, gensym("ft1")); + return (x); +} + +void reson_setup() +{ + sigreson_class = class_new(gensym("reson~"), (t_newmethod)sigreson_new, + (t_method)sigreson_ff, sizeof(t_sigreson), 0, + A_DEFFLOAT, A_DEFFLOAT, 0); + class_addfloat(sigreson_class, (t_method)sigreson_float); + class_addmethod(sigreson_class, (t_method)sigreson_ft1, gensym("ft1"), A_FLOAT, 0); + class_addmethod(sigreson_class, (t_method)nullfn, &s_signal, A_NULL); + class_addmethod(sigreson_class, (t_method)sigreson_dsp, gensym("dsp"), A_NULL); +} + |