From cdf8ded57019d5c905f16422d40be7b1a18ab3bc Mon Sep 17 00:00:00 2001
From: Tom Schouten <doelie@users.sourceforge.net>
Date: Tue, 21 Jan 2003 10:18:19 +0000
Subject: This commit was generated by cvs2svn to compensate for changes in
 r350, which included commits to RCS files with non-trunk default branches.

svn path=/trunk/externals/creb/; revision=351
---
 modules/lattice.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 143 insertions(+)
 create mode 100644 modules/lattice.c

(limited to 'modules/lattice.c')

diff --git a/modules/lattice.c b/modules/lattice.c
new file mode 100644
index 0000000..9403393
--- /dev/null
+++ b/modules/lattice.c
@@ -0,0 +1,143 @@
+/*
+ *   lattice.c  - a lattice filter for pd
+ *   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.
+ */
+
+
+
+#include "m_pd.h"
+#include <math.h>
+
+#define maxorder 1024
+
+typedef struct latticesegment
+{
+    t_float delay; // delay element
+    t_float rc;    // reflection coefficient
+} t_latticesegment;
+
+typedef struct latticectl
+{
+    t_latticesegment c_segment[maxorder]; // array of lattice segment data
+    t_int c_segments;
+} t_latticectl;
+
+typedef struct lattice
+{
+  t_object x_obj;
+  t_float x_f;
+  t_latticectl x_ctl;
+} t_lattice;
+
+
+
+static t_int *lattice_perform(t_int *w)
+{
+
+
+  t_float *in    = (float *)(w[3]);
+  t_float *out    = (float *)(w[4]);
+  t_latticectl *ctl  = (t_latticectl *)(w[1]);
+  t_int i,j;
+  t_int n = (t_int)(w[2]);
+  t_float x,rc,d;
+
+  t_latticesegment* seg = ctl->c_segment;
+  t_int segments = ctl->c_segments;
+  for (i=0; i<n; i++)
+  {
+      x = *in++;
+      // section 0
+      rc = seg[0].rc;
+      x += seg[0].delay * rc;
+      
+      // section 1 to segments-1
+      for (j=1; j < segments; j++)
+      {
+	  rc = seg[j].rc;
+	  d  = seg[j].delay;
+	  x += d * rc;
+	  seg[j-1].delay = d - rc * x; 
+      }
+      // stub
+      seg[segments-1].delay = x;
+
+      *out++ = x;
+  }
+
+  return (w+5);
+}
+
+static void lattice_dsp(t_lattice *x, t_signal **sp)
+{
+    dsp_add(lattice_perform, 4, &x->x_ctl, sp[0]->s_n, sp[0]->s_vec, sp[1]->s_vec);
+
+}                                  
+static void lattice_free(void)
+{
+
+}
+
+t_class *lattice_class;
+
+static void lattice_rc(t_lattice *x, t_float segment, t_float refco)
+{
+    t_int seg = (t_float)segment;
+    if ((seg >= 0) && (seg < x->x_ctl.c_segments)){
+	if (refco > 1.0f) refco = 1.0f;
+	if (refco < -1.0f) refco = -1.0f;
+	x->x_ctl.c_segment[seg].rc = refco;
+    }
+}
+
+static void lattice_reset(t_lattice *x)
+{
+    t_float* buf = (t_float *)x->x_ctl.c_segment;
+    t_int n = x->x_ctl.c_segments;
+    t_int i;
+    for (i=0; i<n; i++) buf[i]=0;
+}
+
+static void *lattice_new(t_floatarg segments)
+{
+    t_lattice *x = (t_lattice *)pd_new(lattice_class);
+    t_int seg = (t_int)segments;
+
+    outlet_new(&x->x_obj, gensym("signal")); 
+
+    if (seg < 1) seg = 1;
+    if (seg > maxorder) seg = maxorder;
+
+    x->x_ctl.c_segments = seg;
+
+    lattice_reset(x);
+
+    return (void *)x;
+}
+
+void lattice_tilde_setup(void)
+{
+  //post("lattice~ v0.1");
+    lattice_class = class_new(gensym("lattice~"), (t_newmethod)lattice_new,
+    	(t_method)lattice_free, sizeof(t_lattice), 0, A_DEFFLOAT, 0);
+    CLASS_MAINSIGNALIN(lattice_class, t_lattice, x_f); 
+    class_addmethod(lattice_class, (t_method)lattice_dsp, gensym("dsp"), 0); 
+    class_addmethod(lattice_class, (t_method)lattice_reset, gensym("reset"), 0); 
+    class_addmethod(lattice_class, (t_method)lattice_rc, gensym("rc"), A_FLOAT, A_FLOAT, 0); 
+
+}
+
-- 
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