From a0f8c026117d1bbe094894d614136efea4b65c97 Mon Sep 17 00:00:00 2001
From: "N.N." <krzyszcz@users.sourceforge.net>
Date: Thu, 14 Aug 2003 14:32:00 +0000
Subject: 10 new sickle classes

svn path=/trunk/externals/miXed/; revision=846
---
 cyclone/sickle/lores.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 cyclone/sickle/lores.c

(limited to 'cyclone/sickle/lores.c')

diff --git a/cyclone/sickle/lores.c b/cyclone/sickle/lores.c
new file mode 100644
index 0000000..9449947
--- /dev/null
+++ b/cyclone/sickle/lores.c
@@ -0,0 +1,109 @@
+/* Copyright (c) 2003 krzYszcz and others.
+ * For information on usage and redistribution, and for a DISCLAIMER OF ALL
+ * WARRANTIES, see the file, "LICENSE.txt," in this distribution.  */
+
+/* The general two-pole resonator (csound's lp2).  For a nice analysis
+   see section 9.1.3 of ``Introduction to Digital Filters'' by Smith. */
+
+/* CHECKME if creation args (or defaults) restored after signal disconnection */
+
+#include <math.h>
+#include "m_pd.h"
+#include "shared.h"
+#include "sickle/sic.h"
+
+#if defined(NT) || defined(MACOSX)
+/* cf pd/src/x_arithmetic.c */
+#define expf  exp
+#define cosf  cos
+#endif
+
+/* CHECKME negative resonance */
+/* CHECKME max resonance, esp. at low freqs (watch out, gain not normalized) */
+#define LORES_MAXRESONANCE  (1. - 1e-20)
+#define LORES_MINOMEGA      .0001         /* CHECKME */
+#define LORES_MAXOMEGA      SHARED_PI     /* CHECKME */
+
+typedef struct _lores
+{
+    t_sic  x_sic;
+    float  x_srcoef;
+    float  x_ynm1;
+    float  x_ynm2;
+} t_lores;
+
+static t_class *lores_class;
+
+static void lores_clear(t_lores *x)
+{
+    x->x_ynm1 = x->x_ynm2 = 0.;
+}
+
+/* LATER make ready for optional audio-rate modulation
+   (separate scalar case routines, use sic_makecostable(), etc.) */
+static t_int *lores_perform(t_int *w)
+{
+    t_lores *x = (t_lores *)(w[1]);
+    int nblock = (int)(w[2]);
+    t_float *xin = (t_float *)(w[3]);
+    t_float fin0 = *(t_float *)(w[4]);
+    t_float rin0 = *(t_float *)(w[5]);
+    t_float *out = (t_float *)(w[6]);
+    float ynm1 = x->x_ynm1;
+    float ynm2 = x->x_ynm2;
+    /* CHECKME sampled once per block */
+    float omega = fin0 * x->x_srcoef;
+    float radius, c1, c2, b0;
+    if (omega < LORES_MINOMEGA)
+	omega = LORES_MINOMEGA;
+    else if (omega > LORES_MAXOMEGA)
+	omega = LORES_MAXOMEGA;
+    if (rin0 > LORES_MAXRESONANCE)
+	rin0 = LORES_MAXRESONANCE;
+    /* radius = pow(base, rin0 - 1), which maps rin0 of 0..1 to radius
+       of 1/base..1, where base=exp(.125), and 1/base=.882496902585 */
+    radius = expf(rin0 * .125) * .882496902585;
+    c1 = 2. * radius * cos(omega);
+    c2 = radius * radius;
+    b0 = 1. - c1 + c2;
+    while (nblock--)
+    {
+	float yn;
+	*out++ = yn = b0 * *xin++ + c1 * ynm1 - c2 * ynm2;
+	ynm2 = ynm1;
+	ynm1 = yn;
+    }
+    /* LATER rethink */
+    x->x_ynm1 = (PD_BADFLOAT(ynm1) ? 0. : ynm1);
+    x->x_ynm2 = (PD_BADFLOAT(ynm2) ? 0. : ynm2);
+    return (w + 7);
+}
+
+static void lores_dsp(t_lores *x, t_signal **sp)
+{
+    x->x_srcoef = SHARED_2PI / sp[0]->s_sr;
+    lores_clear(x);
+    dsp_add(lores_perform, 6, x, sp[0]->s_n,
+	    sp[0]->s_vec, sp[1]->s_vec, sp[2]->s_vec, sp[3]->s_vec);
+}
+
+static void *lores_new(t_floatarg f1, t_floatarg f2)
+{
+    t_lores *x = (t_lores *)pd_new(lores_class);
+    x->x_srcoef = SHARED_2PI / sys_getsr();
+    sic_newinlet((t_sic *)x, f1);
+    sic_newinlet((t_sic *)x, f2);
+    outlet_new((t_object *)x, &s_signal);
+    lores_clear(x);
+    return (x);
+}
+
+void lores_tilde_setup(void)
+{
+    lores_class = class_new(gensym("lores~"),
+			    (t_newmethod)lores_new, 0,
+			    sizeof(t_lores), 0,
+			    A_DEFFLOAT, A_DEFFLOAT, 0);
+    sic_setup(lores_class, lores_dsp, SIC_FLOATTOSIGNAL);
+    class_addmethod(lores_class, (t_method)lores_clear, gensym("clear"), 0);
+}
-- 
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