puredata/6.externs/dspobj~.c

   1 #include "m_pd.h"
   2 #ifdef NT
   3 #pragma warning( disable : 4244 )
   4 #pragma warning( disable : 4305 )
   5 #endif
   6
   7 /* ------------------------ dspobj~ ----------------------------- */
   8
   9 /* tilde object to take absolute value. */
  10
  11 static t_class *dspobj_class;
  12
  13 typedef struct _dspobj
  14 {
  15     t_object x_obj;     /* obligatory header */
  16     t_float x_f;        /* place to hold inlet's value if it's set by message */
  17 } t_dspobj;
  18
  19     /* this is the actual performance routine which acts on the samples.
  20     It's called with a single pointer "w" which is our location in the
  21     DSP call list.  We return a new "w" which will point to the next item
  22     after us.  Meanwhile, w[0] is just a pointer to dsp-perform itself
  23     (no use to us), w[1] and w[2] are the input and output vector locations,
  24     and w[3] is the number of points to calculate. */
  25 static t_int *dspobj_perform(t_int *w)
  26 {
  27     t_float *in = (t_float *)(w[1]);
  28     t_float *out = (t_float *)(w[2]);
  29     int n = (int)(w[3]);
  30     while (n--)
  31     {
  32         float f = *(in++);
  33         *out++ = (f > 0 ? f : -f);
  34     }
  35     return (w+4);
  36 }
  37
  38     /* called to start DSP.  Here we call Pd back to add our perform
  39     routine to a linear callback list which Pd in turn calls to grind
  40     out the samples. */
  41 static void dspobj_dsp(t_dspobj *x, t_signal **sp)
  42 {
  43     dsp_add(dspobj_perform, 3, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);
  44 }
  45
  46 static void *dspobj_new(void)
  47 {
  48     t_dspobj *x = (t_dspobj *)pd_new(dspobj_class);
  49     outlet_new(&x->x_obj, gensym("signal"));
  50     x->x_f = 0;
  51     return (x);
  52 }
  53
  54     /* this routine, which must have exactly this name (with the "~" replaced
  55     by "_tilde) is called when the code is first loaded, and tells Pd how
  56     to build the "class". */
  57 void dspobj_tilde_setup(void)
  58 {
  59     dspobj_class = class_new(gensym("dspobj~"), (t_newmethod)dspobj_new, 0,
  60         sizeof(t_dspobj), 0, A_DEFFLOAT, 0);
  61             /* this is magic to declare that the leftmost, "main" inlet
  62             takes signals; other signal inlets are done differently... */
  63     CLASS_MAINSIGNALIN(dspobj_class, t_dspobj, x_f);
  64         /* here we tell Pd about the "dsp" method, which is called back
  65         when DSP is turned on. */
  66     class_addmethod(dspobj_class, (t_method)dspobj_dsp, gensym("dsp"), 0);
  67 }