add a biquad with audio inlet for coefficients.

add abstraction to compute a set of standard filter : 
low pass / high pass / band pass / band cut / low shelf and high shelf
 

svn path=/trunk/externals/nusmuk/; revision=10069

1 files changed, 112 insertions, 0 deletions

diff --git a/biquad/bq~.c b/biquad/bq~.c
new file mode 100644
index 0000000..d8a70b4
--- /dev/null
+++ b/biquad/bq~.c
@@ -0,0 +1,112 @@
+/* Copyright (c) 1997-1999 Miller Puckette.
+* For information on usage and redistribution, and for a DISCLAIMER OF ALL
+* WARRANTIES, see the file, "LICENSE.txt," in this distribution.  */
+
+// modification of this code by cyrille henry in order to change the biquad topology and add audio inlet for filter coefs
+
+#include "m_pd.h"
+#include <math.h>
+
+/* ---------------- bq~ - raw bq filter ----------------- */
+
+typedef struct bqctl
+{
+    t_sample c_x1;
+    t_sample c_x2;
+    t_sample c_y1;
+    t_sample c_y2;
+} t_bqctl;
+
+typedef struct bq_tilde
+{
+    t_object x_obj;
+    t_float x_f;
+    t_bqctl x_cspace;
+    t_bqctl *x_ctl;
+} t_bq_tilde;
+
+t_class *bq_tilde_class;
+
+static void *bq_tilde_new(t_symbol *s, int argc, t_atom *argv)
+{
+    t_bq_tilde *x = (t_bq_tilde *)pd_new(bq_tilde_class);
+    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_signal, &s_signal);
+    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_signal, &s_signal);
+    inlet_new(&x->x_obj, &x->x_obj.ob_pd, &s_signal, &s_signal);
+    outlet_new(&x->x_obj, &s_signal);
+    x->x_ctl = &x->x_cspace;
+    x->x_cspace.c_x1 = x->x_cspace.c_x2 = 0;
+    x->x_cspace.c_y1 = x->x_cspace.c_y2 = 0;
+    x->x_f = 0;
+    return (x);
+}
+
+static t_int *bq_tilde_perform(t_int *w)
+{
+    t_sample *in = (t_sample *)(w[1]);
+    t_sample *ina1 = (t_sample *)(w[2]);
+    t_sample *ina2 = (t_sample *)(w[3]);
+    t_sample *inb1 = (t_sample *)(w[4]);
+    t_sample *inb2 = (t_sample *)(w[5]);
+    t_sample *inb3 = (t_sample *)(w[6]);
+    t_sample *out = (t_sample *)(w[7]);
+    t_bqctl *c = (t_bqctl *)(w[8]);
+    int n = (t_int)(w[9]);
+    int i;
+    t_sample last_in = c->c_x1;
+    t_sample prev_in = c->c_x2;
+    t_sample last_out = c->c_y1;
+    t_sample prev_out = c->c_y2;
+
+    for (i = 0; i < n; i++)
+    {
+        t_sample output =  *inb1++ * *in + *inb2++ * last_in + *inb3++ * prev_in - *ina1++ * last_out - *ina2++ * prev_out;
+//        if (PD_BIGORSMALL(output))
+//            output = 0; i don't understnd why it did not compile with this 2 lines. 
+// should be fixed latter if denormal is a problem
+        *out++ = output; 
+        prev_in = last_in;
+        prev_out = last_out;
+        last_out = output;
+        last_in = *in++;
+    }
+    c->c_x1 = last_in;
+    c->c_x2 = prev_in;
+    c->c_y1 = last_out;
+    c->c_y2 = prev_out;
+
+    return (w+10);
+}
+
+static void bq_tilde_set(t_bq_tilde *x, t_symbol *s, int argc, t_atom *argv)
+{
+    t_bqctl *c = x->x_ctl;
+    c->c_x1 = atom_getfloatarg(0, argc, argv);
+    c->c_x2 = atom_getfloatarg(1, argc, argv);
+    c->c_y1 = atom_getfloatarg(2, argc, argv);
+    c->c_y2 = atom_getfloatarg(3, argc, argv);
+}
+
+static void bq_tilde_dsp(t_bq_tilde *x, t_signal **sp)
+{
+    dsp_add(bq_tilde_perform, 9,
+        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, x->x_ctl, sp[0]->s_n);
+
+}
+
+void bq_tilde_setup(void)
+{
+    bq_tilde_class = class_new(gensym("bq~"), (t_newmethod)bq_tilde_new,
+        0, sizeof(t_bq_tilde), 0, A_GIMME, 0);
+    CLASS_MAINSIGNALIN(bq_tilde_class, t_bq_tilde, x_f);
+    class_addmethod(bq_tilde_class, (t_method)bq_tilde_dsp, gensym("dsp"), 0);
+    class_addmethod(bq_tilde_class, (t_method)bq_tilde_set, gensym("set"),
+        A_GIMME, 0);
+    class_addmethod(bq_tilde_class, (t_method)bq_tilde_set, gensym("clear"),
+        A_GIMME, 0);
+}
+
+