From d0a14104c6848efc384075f6669a301b515c5a16 Mon Sep 17 00:00:00 2001
From: Cyrille Henry <nusmuk@users.sourceforge.net>
Date: Mon, 1 Jun 2009 13:53:17 +0000
Subject: add a work in progress vd~  object with "better" interpolation
 algorythm.

svn path=/trunk/externals/nusmuk/; revision=11606
---
 tab/vdc~-help.pd | 18 +++++++++++
 tab/vdc~.c       | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 111 insertions(+)
 create mode 100644 tab/vdc~-help.pd
 create mode 100644 tab/vdc~.c

diff --git a/tab/vdc~-help.pd b/tab/vdc~-help.pd
new file mode 100644
index 0000000..ce59096
--- /dev/null
+++ b/tab/vdc~-help.pd
@@ -0,0 +1,18 @@
+#N canvas 695 59 307 351 12;
+#X floatatom 35 39 0 0 0 0 - - -;
+#X text 115 131 signal output (delayed signal);
+#X obj 35 67 sig~;
+#X text 84 64 signal input (delay time in ms);
+#X text 178 97 creation argument: name of delay line;
+#X obj 31 297 phasor~;
+#X msg 31 272 222;
+#X obj 31 248 loadbang;
+#X obj 34 159 oscillo~;
+#X obj 34 92 vdc~ test;
+#X obj 32 322 delwrite~ test 1000;
+#X connect 0 0 2 0;
+#X connect 2 0 9 0;
+#X connect 5 0 10 0;
+#X connect 6 0 5 0;
+#X connect 7 0 6 0;
+#X connect 9 0 8 0;
diff --git a/tab/vdc~.c b/tab/vdc~.c
new file mode 100644
index 0000000..c2efbd0
--- /dev/null
+++ b/tab/vdc~.c
@@ -0,0 +1,93 @@
+#include "m_pd.h"
+#include "d_delay.c"
+
+
+/* ----------------------------- vdc~ ----------------------------- */
+static t_class *sigvdc_class;
+
+typedef struct _sigvdc
+{
+    t_object x_obj;
+    t_symbol *x_sym;
+    t_float x_sr;       /* samples per msec */
+    int x_zerodel;      /* 0 or vecsize depending on read/write order */
+    t_float x_f;
+} t_sigvdc;
+
+static void *sigvdc_new(t_symbol *s)
+{
+    t_sigvdc *x = (t_sigvdc *)pd_new(sigvdc_class);
+    if (!*s->s_name) s = gensym("vdc~");
+    x->x_sym = s;
+    x->x_sr = 1;
+    x->x_zerodel = 0;
+    outlet_new(&x->x_obj, &s_signal);
+    x->x_f = 0;
+    return (x);
+}
+
+
+static t_int *sigvdc_perform(t_int *w)
+{
+    t_sample *in = (t_sample *)(w[1]);
+    t_sample *out = (t_sample *)(w[2]);
+    t_delwritectl *ctl = (t_delwritectl *)(w[3]);
+    t_sigvdc *x = (t_sigvdc *)(w[4]);
+    int n = (int)(w[5]);
+
+    int nsamps = ctl->c_n;
+    t_sample limit = nsamps - n - 1;
+    t_sample fn = n-1;
+    t_sample *vp = ctl->c_vec, *bp, *wp = vp + ctl->c_phase;
+    t_sample zerodel = x->x_zerodel;
+    while (n--)
+    {
+        t_sample delsamps = x->x_sr * *in++ - zerodel, frac;
+        int idelsamps;
+        t_sample a, b, c, d, cminusb;
+        if (delsamps < 1.00001f) delsamps = 1.00001f;
+        if (delsamps > limit) delsamps = limit;
+        delsamps += fn;
+        fn = fn - 1.0f;
+        idelsamps = delsamps;
+        frac = delsamps - (t_sample)idelsamps;
+        bp = wp - idelsamps;
+        if (bp < vp + 4) bp += nsamps;
+        d = bp[-3];
+        c = bp[-2];
+        b = bp[-1];
+        a = bp[0];
+        cminusb = c-b;
+        *out++ = b + frac * (
+            cminusb - 0.1666667f * (1.-frac) * (
+                (d - a - 3.0f * cminusb) * frac + (d + 2.0f*a - 3.0f*b)
+            )
+        );
+    }
+    return (w+6);
+}
+
+static void sigvdc_dsp(t_sigvdc *x, t_signal **sp)
+{
+    t_sigdelwrite *delwriter =
+        (t_sigdelwrite *)pd_findbyclass(x->x_sym, sigdelwrite_class);
+    x->x_sr = sp[0]->s_sr * 0.001;
+    if (delwriter)
+    {
+        sigdelwrite_checkvecsize(delwriter, sp[0]->s_n);
+        x->x_zerodel = (delwriter->x_sortno == ugen_getsortno() ?
+            0 : delwriter->x_vecsize);
+        dsp_add(sigvdc_perform, 5,
+            sp[0]->s_vec, sp[1]->s_vec,
+                &delwriter->x_cspace, x, sp[0]->s_n);
+    }
+    else error("vdc~: %s: no such delwrite~",x->x_sym->s_name);
+}
+
+void vdc_tilde_setup(void)
+{
+    sigvdc_class = class_new(gensym("vdc~"), (t_newmethod)sigvdc_new, 0,
+        sizeof(t_sigvdc), 0, A_DEFSYM, 0);
+    class_addmethod(sigvdc_class, (t_method)sigvdc_dsp, gensym("dsp"), 0);
+    CLASS_MAINSIGNALIN(sigvdc_class, t_sigvdc, x_f);
+}
-- 
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