1 files changed, 77 insertions, 0 deletions
diff --git a/source/hip.c b/source/hip.c
new file mode 100644
index 0000000..b1425c1
--- /dev/null
+++ b/source/hip.c
@@ -0,0 +1,77 @@
+#include "defines.h"
+
+/*--------------- hip ---------------*/
+
+typedef struct hipctl
+{
+    float c_x;
+    float c_coef;
+} t_hipctl;
+
+typedef struct hip
+{
+    t_object x_obj;
+    float x_sr;
+    float x_hz;
+    t_hipctl x_cspace;
+    t_hipctl *x_ctl;
+    float x_f;
+} t_hip;
+
+t_class *hip_class;
+
+static void hip_ft1(t_hip *x, t_floatarg f);
+
+static void *hip_new(t_floatarg f)
+{
+    t_hip *x = (t_hip *)pd_new(hip_class);
+    inlet_new(&x->x_obj, &x->x_obj.ob_pd, gensym("float"), gensym("ft1"));
+    outlet_new(&x->x_obj, gensym("float"));
+    x->x_ctl = &x->x_cspace;
+    x->x_cspace.c_x = 0;
+    hip_ft1(x, f);
+    x->x_f = 0;
+    return (x);
+}
+
+static void hip_ft1(t_hip *x, t_floatarg f)
+{
+    if (f < 0.001) f = 10;
+    x->x_hz = f;
+    x->x_ctl->c_coef = 1 - f * (2 * 3.14159f);
+    if (x->x_ctl->c_coef < 0) x->x_ctl->c_coef = 0;
+}
+
+static void hip_perform(t_hip *x, t_float in)
+{
+    t_hipctl *c = x->x_ctl;
+    float last = c->c_x;
+    float coef = c->c_coef;
+	float out;
+
+	float new = in + coef * last;
+	out = new - last;
+	last = new;
+
+	/* NAN protect */
+    if (!((last <= 0) || (last >= 0)))
+    	last = 0;
+    c->c_x = last;
+
+    outlet_float(x->x_obj.ob_outlet, out);
+}
+
+static void hip_clear(t_hip *x, t_floatarg q)
+{
+    x->x_cspace.c_x = 0;
+}
+
+void hip_setup(void)
+{
+    hip_class = class_new(gensym("hip"), (t_newmethod)hip_new, 0,
+	sizeof(t_hip), 0, A_DEFFLOAT, 0);
+	class_addfloat(hip_class, (t_method)hip_perform);
+    class_addmethod(hip_class, (t_method)hip_ft1,
+    	gensym("ft1"), A_FLOAT, 0);
+    class_addmethod(hip_class, (t_method)hip_clear, gensym("clear"), 0);
+}
+\ No newline at end of file