diff options
Diffstat (limited to 'pd/doc/6.externs')
| -rw-r--r-- | pd/doc/6.externs/dspobj~.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/pd/doc/6.externs/dspobj~.c b/pd/doc/6.externs/dspobj~.c index a8841f21..5c3fa86b 100644 --- a/pd/doc/6.externs/dspobj~.c +++ b/pd/doc/6.externs/dspobj~.c @@ -12,9 +12,16 @@ static t_class *dspobj_class; typedef struct _dspobj { - t_object x_obj; + t_object x_obj; /* obligatory header */ + t_float x_f; /* place to hold inlet's value if it's set by message */ } t_dspobj; + /* this is the actual performance routine which acts on the samples. + It's called with a single pointer "w" which is our location in the + DSP call list. We return a new "w" which will point to the next item + after us. Meanwhile, w[0] is just a pointer to dsp-perform itself + (no use to us), w[1] and w[2] are the input and output vector locations, + and w[3] is the number of points to calculate. */ static t_int *dspobj_perform(t_int *w) { t_float *in = (t_float *)(w[1]); @@ -28,6 +35,9 @@ static t_int *dspobj_perform(t_int *w) return (w+4); } + /* called to start DSP. Here we call Pd back to add our perform + routine to a linear callback list which Pd in turn calls to grind + out the samples. */ static void dspobj_dsp(t_dspobj *x, t_signal **sp) { dsp_add(dspobj_perform, 3, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n); @@ -37,13 +47,21 @@ static void *dspobj_new(void) { t_dspobj *x = (t_dspobj *)pd_new(dspobj_class); outlet_new(&x->x_obj, gensym("signal")); + x->x_f = 0; return (x); } + /* this routine, which must have exactly this name (with the "~" replaced + by "_tilde) is called when the code is first loaded, and tells Pd how + to build the "class". */ void dspobj_tilde_setup(void) { dspobj_class = class_new(gensym("dspobj~"), (t_newmethod)dspobj_new, 0, sizeof(t_dspobj), 0, A_DEFFLOAT, 0); - class_addmethod(dspobj_class, nullfn, gensym("signal"), 0); + /* this is magic to declare that the leftmost, "main" inlet + takes signals; other signal inlets are done differently... */ + CLASS_MAINSIGNALIN(dspobj_class, t_dspobj, x_f); + /* here we tell Pd about the "dsp" method, which is called back + when DSP is turned on. */ class_addmethod(dspobj_class, (t_method)dspobj_dsp, gensym("dsp"), 0); } |