1 files changed, 83 insertions, 0 deletions
diff --git a/source/saturate~.c b/source/saturate~.c
new file mode 100644
index 0000000..809f7a0
--- /dev/null
+++ b/source/saturate~.c
@@ -0,0 +1,83 @@
+/* sIgpAck
+ * for
+ * pure-data
+ * www.weiss-archiv.de */
+
+#include "m_pd.h"
+#include <math.h>
+#ifdef _MSC_VER
+#pragma warning( disable : 4244 )
+#pragma warning( disable : 4305 )
+#endif
+
+/* ------------------------ sp.saturate~ ----------------------------- */
+/* signal soft saturation */
+/* code from www.musicdsp.org posted by bram de jong */
+
+static t_class *saturate_tilde_class;
+
+typedef struct _saturate_tilde
+{
+    t_object x_obj;
+	t_sample x_thresh;
+	float x_f;
+} t_saturate_tilde;
+
+static void *saturate_tilde_new(t_floatarg thresh)
+{
+    t_saturate_tilde *x = (t_saturate_tilde *)pd_new(saturate_tilde_class);
+	x->x_thresh = thresh;
+    outlet_new(&x->x_obj, gensym("signal"));
+	floatinlet_new(&x->x_obj, &x->x_thresh);
+	x->x_f = 0;
+	if(thresh) x->x_thresh = thresh;
+	else x->x_thresh = 1.;
+    return (x);
+}
+
+static float sigmoid(float x)
+{
+	if(fabs(x) < 1)
+		return x * (1.5f - 0.5f * x * x);
+	else
+		return x > 0.f ? 1.f : -1.f;
+}
+
+static t_int *saturate_tilde_perform(t_int *w)
+{
+	t_saturate_tilde *x = (t_saturate_tilde *)(w[1]);
+    t_float *in = (t_float *)(w[2]);
+    t_float *out = (t_float *)(w[3]);
+    int n = (int)(w[4]);
+	float f, value;
+	float t = x->x_thresh;
+    while (n--)
+    {
+		f = *in++;
+		if(fabs(f) < t)
+			value = f;
+		else
+		{
+			if(f > 0.f)
+				value = t + (1.f - t) * sigmoid((f - t)/((1 - t) * 1.5f));
+			else
+				value = -(t + (1.f - t) * sigmoid((-f - t)/((1 - t) * 1.5f)));
+		}
+		*out++ = value;
+    }
+    return (w+5);
+}
+
+static void saturate_tilde_dsp(t_saturate_tilde *x, t_signal **sp)
+{
+    dsp_add(saturate_tilde_perform, 4, x, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);
+}
+
+void saturate_tilde_setup(void)
+{
+    saturate_tilde_class = class_new(gensym("sp.saturate~"), (t_newmethod)saturate_tilde_new, 0,
+    	sizeof(t_saturate_tilde), 0, A_DEFFLOAT, 0);
+    CLASS_MAINSIGNALIN(saturate_tilde_class, t_saturate_tilde, x_f);
+    class_addmethod(saturate_tilde_class, (t_method)saturate_tilde_dsp, gensym("dsp"), 0);
+	class_addmethod(saturate_tilde_class, (t_method)saturate_tilde_dsp, gensym("sigmoid"), A_FLOAT, 0);
+}