1 files changed, 130 insertions, 0 deletions
diff --git a/src/autowah.cc b/src/autowah.cc
new file mode 100644
index 0000000..a18c8d3
--- /dev/null
+++ b/src/autowah.cc
@@ -0,0 +1,130 @@
+/*
+    Copyright (C) 2009 Fons Adriaensen <fons@kokkinizita.net>
+    
+    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 <math.h>
+#include <string.h>
+#include "autowah.h"
+
+
+void Ladspa_Autowah::setport (PortIndex port, PortData *data)
+{
+	_port [port] = (float*)data;
+}
+
+
+#define G_RES 4.0f
+#define F_MIN 300.0f
+#define F_RAT 10
+#define B_MIN 0.03f
+#define B_RAT 4
+#define T_MIN 0.05f 
+#define T_LOG 2
+
+
+void Ladspa_Autowah::active (bool act)
+{
+    if (! act) return;
+
+    _wbase = F_MIN * 6.28f / _fsam;
+    _bbase = B_MIN;
+    _rfact = 64.0f / (_fsam * T_MIN);
+    _z1 = _z2 = 0;
+    _s1 = _s2 = 0;
+    _gx = _gy = 0;
+    _dr = 0;
+}
+
+
+void Ladspa_Autowah::runproc (SampleCount len, bool add)
+{
+    int   i, k;
+    float *inp = _port [A_INP];
+    float *out = _port [A_OUT];
+    float z1, z2, s1, s2, gx, gy;
+    float ds1, ds2, dgx, dgy;
+    float gd, rf, md, fr, dr;
+    float b, p, t, w, x, y;
+
+    gx = _gx;
+    gy = _gy;
+    t = _port [C_OPMIX][0];
+    _gy = G_RES * t;
+    _gx = _gy + 1 - t;
+    dgx = (_gx - gx) / len;
+    dgy = (_gy - gy) / len;
+
+    gd = 10 * powf (10.0f, 0.05f * _port [C_DRIVE][0]);
+    rf = 1.0f - _rfact / powf (10.0f, T_LOG * _port [C_DECAY][0]);
+    md = _port [C_RANGE][0];
+    fr = _port [C_FREQ][0];
+
+    z1 = _z1;
+    z2 = _z2;
+    s1 = _s1;
+    s2 = _s2;
+    dr = _dr;
+
+    while (len)
+    {
+	k = (len > 80) ? 64 : len;
+
+	p = 0;
+	for (i = 0; i < k; i++)
+	{
+	    x = inp [i];
+	    p += x * x;
+	}
+	p = gd * sqrtf (p / k);
+
+	if (p > dr) dr += 0.1f *(p - dr);
+	if (dr > md) dr = md;
+	t = dr + fr; 
+	dr = dr * rf + 1e-10f;
+	w = _wbase  * (1 + (F_RAT - 1) * t * t); 
+	b = w * _bbase * (1 + (B_RAT - 1) * t);
+        if (w > 0.7f) w = 0.7f;
+
+	_s1 = -cosf (w);
+	_s2 = (1 - b) / (1 + b);
+	ds1 = (_s1 - s1) / k;
+	ds2 = (_s2 - s2) / k;
+  
+	for (i = 0; i < k; i++)
+	{
+	    s1 += ds1;
+	    s2 += ds2;
+            gx += dgx;
+            gy += dgy;
+            x = inp [i];
+            y = x - s2 * z2;
+            out [i] = gx * x - gy * (z2 + s2 * y);                           
+            y -= s1 * z1;
+            z2 = z1 + s1 * y;
+            z1 = y + 1e-10f;
+	}
+	inp += k;
+	out += k;
+	len -= k;
+    }
+
+    _z1 = z1;
+    _z2 = z2;
+    _dr = dr;
+}
+