diff options
Diffstat (limited to 'valverect~.c')
| -rw-r--r-- | valverect~.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/valverect~.c b/valverect~.c new file mode 100644 index 0000000..246878c --- /dev/null +++ b/valverect~.c @@ -0,0 +1,143 @@ +// sigpack
+// for
+// pure-data
+// by weiss
+// www.weiss-archive.de
+
+#include "m_pd.h"
+#include <math.h>
+#include <string.h>
+#ifdef _MSC_VER
+#pragma warning( disable : 4244 )
+#pragma warning( disable : 4305 )
+#endif
+
+// ------------------------ valverect~ -----------------------------
+// valve rectifier
+// code from swh_plugins by steve harris www.plugin.org.uk
+
+// 1.0 / ln(2)
+#define LN2R 1.442695041f
+/* Fast exponentiation function, y = e^x */
+#define f_exp(x) f_pow2(x * LN2R)
+
+static t_class *valverect_tilde_class;
+
+typedef struct _valverect_tilde
+{
+ t_object x_obj;
+ t_sample x_sag;//sag level[0-1]
+ t_sample x_dist_p;//distortion[0-1]
+ unsigned int x_apos;
+ float *x_avg;
+ int x_avg_size;
+ float x_avg_sizer;
+ float x_avgs;
+ float x_lp1tm1;
+ float x_lp2tm1;
+ float x_s_rate;
+ float x_f;
+} t_valverect_tilde;
+
+static void *valverect_tilde_new(t_floatarg sag, t_floatarg dist)
+{
+ t_valverect_tilde *x = (t_valverect_tilde *)pd_new(valverect_tilde_class);
+ x->x_sag = sag;
+ x->x_dist_p = dist;
+ outlet_new(&x->x_obj, gensym("signal"));
+ floatinlet_new(&x->x_obj, &x->x_sag);
+ floatinlet_new(&x->x_obj, &x->x_dist_p);
+ x->x_s_rate = sys_getsr();
+ x->x_avg_size = x->x_s_rate / 9;//number of samples in averaging buffer
+ x->x_avg_sizer = 9.0f / x->x_s_rate;//reciprocal of above
+ x->x_avg = (float *)getbytes(x->x_avg_size * sizeof(float));//averaging buffer
+ memset(x->x_avg, 0, x->x_avg_size * sizeof(float));
+ x->x_avgs = 0.0f;//sum of samples in averaging buffer
+ x->x_apos = 0;//position in averaging buffer
+ x->x_lp1tm1 = 0.0f;//last value in lowpass 1
+ x->x_lp2tm1 = 0.0f;//last value in lowpass 2
+ x->x_f = 0;
+ if (sag) x->x_sag = sag;
+ else x->x_sag = 0.0;
+ if (dist) x->x_dist_p = dist;
+ else x->x_dist_p = 0.0;
+ return (x);
+}
+
+/* Andrew Simper's pow(2, x) aproximation from the music-dsp list */
+static float f_pow2(float x)
+{
+ long *px = (long*)(&x); // store address of float as long pointer
+ const float tx = (x-0.5f) + (3<<22); // temporary value for truncation
+ const long lx = *((long*)&tx) - 0x4b400000; // integer power of 2
+ const float dx = x-(float)(lx); // float remainder of power of 2
+
+ x = 1.0f + dx*(0.6960656421638072f + // cubic apporoximation of 2^x
+ dx*(0.224494337302845f + // for x in the range [0, 1]
+ dx*(0.07944023841053369f)));
+ *px += (lx<<23); // add integer power of 2 to exponent
+
+ return x;
+}
+
+static t_int *valverect_tilde_perform(t_int *w)
+{
+ t_valverect_tilde *x = (t_valverect_tilde *)(w[1]);
+ t_float *in = (t_float *)(w[2]);
+ t_float *out = (t_float *)(w[3]);
+ int n = (int)(w[4]);
+ float abs, q, fx;
+ const float dist = x->x_dist_p * 40.0f + 0.1f;
+ float f;
+ while (n--)
+ {
+ f = *in++;
+ abs = fabs(f);
+ if(abs > x->x_lp1tm1) {
+ x->x_lp1tm1 = abs;
+ }
+ else {
+ x->x_lp1tm1 = 0.9999f * x->x_lp1tm1 + 0.0001f * abs;
+ }
+ x->x_avgs -= x->x_avg[x->x_apos];
+ x->x_avgs += x->x_lp1tm1;
+ x->x_avg[x->x_apos] = x->x_lp1tm1;
+ x->x_apos %= x->x_avg_size;
+
+ x->x_lp2tm1 = 0.999f * x->x_lp2tm1 + x->x_avgs * x->x_avg_sizer * 0.001f;
+ q = x->x_lp1tm1 * x->x_sag - x->x_lp2tm1 * 1.02f - 1.0f;
+ if(q > -0.01f) {
+ q = -0.01f;
+ }
+ else if(q < -1.0f) {
+ q = -1.0f;
+ }
+
+ if(f == q) {
+ fx = 1.0f / dist + q / (1.0f - f_exp(dist * q));
+ }
+ else {
+ fx = (f - q) / (1.0f - f_exp(-dist * (f - q))) + q / (1.0f - f_exp(dist * q));
+ }
+ *out++ = fx;
+ }
+ return (w+5);
+}
+
+static void valverect_tilde_dsp(t_valverect_tilde *x, t_signal **sp)
+{
+ dsp_add(valverect_tilde_perform, 4, x, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);
+}
+
+static void valverect_tilde_free(t_valverect_tilde *x)
+{
+ freebytes(x->x_avg, x->x_avg_size * sizeof(float));
+}
+
+void valverect_tilde_setup(void)
+{
+ valverect_tilde_class = class_new(gensym("valverect~"), (t_newmethod)valverect_tilde_new, (t_method)valverect_tilde_free,
+ sizeof(t_valverect_tilde), 0, A_DEFFLOAT, A_DEFFLOAT, 0);
+ CLASS_MAINSIGNALIN(valverect_tilde_class, t_valverect_tilde, x_f);
+ class_addmethod(valverect_tilde_class, (t_method)valverect_tilde_dsp, gensym("dsp"), 0);
+}
|