From da1f0065d07250b86b9a761b012987e4825f491f Mon Sep 17 00:00:00 2001
From: Hans-Christoph Steiner <eighthave@users.sourceforge.net>
Date: Mon, 28 Nov 2005 16:53:25 +0000
Subject: This commit was generated by cvs2svn to compensate for changes in
 r4068, which included commits to RCS files with non-trunk default branches.

svn path=/trunk/externals/smlib/; revision=4069
---
 source/bp.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 source/bp.c

(limited to 'source/bp.c')

diff --git a/source/bp.c b/source/bp.c
new file mode 100644
index 0000000..d21bc19
--- /dev/null
+++ b/source/bp.c
@@ -0,0 +1,123 @@
+#include "defines.h"
+
+/*--------------- bp ---------------*/
+
+typedef struct bpctl
+{
+    float c_x1;
+    float c_x2;
+    float c_coef1;
+    float c_coef2;
+    float c_gain;
+} t_bpctl;
+
+typedef struct bp
+{
+    t_object x_obj;
+    float x_freq;
+    float x_q;
+    t_bpctl x_cspace;
+    t_bpctl *x_ctl;
+    float x_f;
+} t_bp;
+
+t_class *bp_class;
+
+static void bp_docoef(t_bp *x, t_floatarg f, t_floatarg q);
+
+static void *bp_new(t_floatarg f, t_floatarg q)
+{
+    t_bp *x = (t_bp *)pd_new(bp_class);
+    inlet_new(&x->x_obj, &x->x_obj.ob_pd, gensym("float"), gensym("ft1"));
+    inlet_new(&x->x_obj, &x->x_obj.ob_pd, gensym("float"), gensym("ft2"));
+    outlet_new(&x->x_obj, gensym("float"));
+    x->x_ctl = &x->x_cspace;
+    x->x_cspace.c_x1 = 0;
+    x->x_cspace.c_x2 = 0;
+    bp_docoef(x, f, q);
+    x->x_f = 0;
+    return (x);
+}
+
+static float bp_qcos(float f)
+{
+    if (f >= -(0.5f*3.14159f) && f <= 0.5f*3.14159f)
+    {
+    	float g = f*f;
+    	return (((g*g*g * (-1.0f/720.0f) + g*g*(1.0f/24.0f)) - g*0.5f) + 1);
+    }
+    else return (0);
+}
+
+static void bp_docoef(t_bp *x, t_floatarg f, t_floatarg q)
+{
+    float r, oneminusr, omega;
+    if (f < 0.0001f) f = 0.0001f;
+    if (q < 0) q = 0;
+    x->x_freq = f;
+    x->x_q = q;
+    omega = f * (2.0f * 3.14159f);
+    if (q < 0.001) oneminusr = 1.0f;
+    else oneminusr = omega/q;
+    if (oneminusr > 1.0f) oneminusr = 1.0f;
+    r = 1.0f - oneminusr;
+    x->x_ctl->c_coef1 = 2.0f * bp_qcos(omega) * r;
+    x->x_ctl->c_coef2 = - r * r;
+    x->x_ctl->c_gain = 2 * oneminusr * (oneminusr + r * omega);
+    /* post("r %f, omega %f, coef1 %f, coef2 %f",
+    	r, omega, x->x_ctl->c_coef1, x->x_ctl->c_coef2); */
+}
+
+static void bp_ft1(t_bp *x, t_floatarg f)
+{
+    bp_docoef(x, f, x->x_q);
+}
+
+static void bp_ft2(t_bp *x, t_floatarg q)
+{
+    bp_docoef(x, x->x_freq, q);
+}
+
+static void bp_clear(t_bp *x, t_floatarg q)
+{
+    x->x_ctl->c_x1 = x->x_ctl->c_x2 = 0;
+}
+
+static void bp_perform(t_bp *x, t_float in)
+{
+	float out;
+    t_bpctl *c = x->x_ctl;
+    float last = c->c_x1;
+    float prev = c->c_x2;
+    float coef1 = c->c_coef1;
+    float coef2 = c->c_coef2;
+    float gain = c->c_gain;
+
+	float output =  in + coef1 * last + coef2 * prev;
+   	out = gain * output;
+
+	prev = last;
+	last = output;
+
+	/* NAN protect */
+    if (!((last <= 0) || (last >= 0)))
+    	last = 0;
+    if (!((prev <= 0) || (prev >= 0)))
+    	prev = 0;
+    c->c_x1 = last;
+    c->c_x2 = prev;
+
+    outlet_float(x->x_obj.ob_outlet, out);
+}
+
+void bp_setup(void)
+{
+    bp_class = class_new(gensym("bp"), (t_newmethod)bp_new, 0,
+	sizeof(t_bp), 0, A_DEFFLOAT, A_DEFFLOAT, 0);
+    class_addfloat(bp_class, (t_method)bp_perform);
+    class_addmethod(bp_class, (t_method)bp_ft1,
+    	gensym("ft1"), A_FLOAT, 0);
+    class_addmethod(bp_class, (t_method)bp_ft2,
+    	gensym("ft2"), A_FLOAT, 0);
+    class_addmethod(bp_class, (t_method)bp_clear, gensym("clear"), 0);
+}
-- 
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