From 179bf7c56f7a8e4df6031d3366548f7afbee31d2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?IOhannes=20m=20zm=C3=B6lnig?= Date: Tue, 31 Jan 2006 10:44:35 +0000 Subject: added the missing examples files; added a LICENSE (all the C-files are under pd's FreeBSD-like license, the HOWTO itself is CreativeCommons-ShareAlike 2.5) svn path=/trunk/; revision=4525 --- doc/tutorials/externals-howto/example3/counter.c | 202 +++++++++++++++++++++++ 1 file changed, 202 insertions(+) create mode 100644 doc/tutorials/externals-howto/example3/counter.c (limited to 'doc/tutorials/externals-howto/example3/counter.c') diff --git a/doc/tutorials/externals-howto/example3/counter.c b/doc/tutorials/externals-howto/example3/counter.c new file mode 100644 index 00000000..4eee6a5e --- /dev/null +++ b/doc/tutorials/externals-howto/example3/counter.c @@ -0,0 +1,202 @@ +/* + * HOWTO write an External for Pure data + * (c) 2001-2006 IOhannes m zmölnig zmoelnig[AT]iem.at + * + * this is the source-code for the third example in the HOWTO + * it creates an object that increments and outputs a counter + * whenever it gets banged. + * the counter value can be "set" to a special value, or "reset" to a default + * an upper and lower boundary can be specified: whenever the counter crosses + * such boundary a "bang" is emitted at the 2nd outlet and the counter value wraps + * + * for legal issues please see the file LICENSE.txt + */ + + +/** + * include the interface to Pd + */ +#include "m_pd.h" + + +/** + * define a new "class" + */ +static t_class *counter_class; + + +/** + * this is the dataspace of our new object + * the first element is the mandatory "t_object" + * then we have all sort of variables for the + * actual counter value, the step-size and the counting boundaries + * finally we have 2 "t_outlet" elements so we can send data + * to a "named" outlet. + */ +typedef struct _counter { + t_object x_obj; /* mandatory t_object */ + t_int i_count; /* the current counter value */ + t_float step; /* step size; + * this is "float" because of the passive inlet we are using */ + t_int i_down, i_up; /* lower and upper boundary */ + t_outlet *f_out, *b_out; /* outlets */ +} t_counter; + + +/** + * this method is called whenever a "bang" is sent to the object + */ +void counter_bang(t_counter *x) +{ + t_float f=x->i_count; + t_int step = x->step; + x->i_count+=step; + + if (x->i_down-x->i_up) { + if ((step>0) && (x->i_count > x->i_up)) { + x->i_count = x->i_down; + /* we crossed the upper boundary, so we send a bang out of + * the 2nd outlet (which is x->b_out) + */ + outlet_bang(x->b_out); + } else if (x->i_count < x->i_down) { + x->i_count = x->i_up; + outlet_bang(x->b_out); + } + } + /* output the current counter value at the 1st outlet (which is x->f_out) */ + outlet_float(x->f_out, f); +} + + +/** + * this is called whenever a "reset" message is sent to the inlet of the object + * since the "reset" message has no arguments (as declared in counter_setup()) + * we only get a reference to the class-dataspace + */ +void counter_reset(t_counter *x) +{ + x->i_count = x->i_down; +} + + +/** + * this is called whenever a "set" message is sent to the inlet of the object + * since the "set" message has one floating-point argument (as declared in counter_setup()) + * we get a reference to the class-dataspace and the value + */ +void counter_set(t_counter *x, t_floatarg f) +{ + x->i_count = f; +} + + +/** + * this is called whenever a "bound" message is sent to the inlet of the object + * note that in counter_new(), we rewrite a list to the 2nd inlet + * to a "bound" message to the 1st inlet + */ +void counter_bound(t_counter *x, t_floatarg f1, t_floatarg f2) +{ + x->i_down = (f1i_up = (f1>f2)?f1:f2; +} + + +/** + * this is the "constructor" of the class + * we expect a variable number of arguments to this object + * symbol "s" is the name of the object itself + * the arguments are given as a t_atom array of argc elements. + */ +void *counter_new(t_symbol *s, int argc, t_atom *argv) +{ + t_counter *x = (t_counter *)pd_new(counter_class); + t_float f1=0, f2=0; + + /* depending on the number of arguments we interprete them differently */ + x->step=1; + switch(argc){ + default: + case 3: + x->step=atom_getfloat(argv+2); + case 2: + f2=atom_getfloat(argv+1); + case 1: + f1=atom_getfloat(argv); + break; + case 0: + } + if (argc<2)f2=f1; + + x->i_down = (f1i_up = (f1>f2)?f1:f2; + + x->i_count=x->i_down; + + /* create a new active inlet for this object + * a message with the selector "list" that is sent + * to this inlet (it is the 2nd inlet from left), + * will be appear to be the same message but with the selector "bound" + * at the 1st inlet. + * the method for "bound" messages is given in counter_setup() + */ + inlet_new(&x->x_obj, &x->x_obj.ob_pd, + gensym("list"), gensym("bound")); + + /* create a passive inlet inlet (it will be the 2rd inlet from left) + * whenever a floating point number is sent to this inlet, + * its value will be immediately stored in "x->step" + * no function will be called + */ + floatinlet_new(&x->x_obj, &x->step); + + /* create a new outlet which will output floats + * we store a reference to this outlet in x->f_out + * so we are able to send data to this very outlet + */ + x->f_out = outlet_new(&x->x_obj, &s_float); + /* create a new outlet which will output bangs */ + x->b_out = outlet_new(&x->x_obj, &s_bang); + + return (void *)x; +} + + +/** + * define the function-space of the class + */ +void counter_setup(void) { + counter_class = class_new(gensym("counter"), + (t_newmethod)counter_new, + 0, sizeof(t_counter), + CLASS_DEFAULT, + A_GIMME, /* an arbitrary number of arguments + * which are of arbitrary type */ + 0); + + /* call a function when a "bang" message appears on the first inlet */ + class_addbang (counter_class, counter_bang); + + /* call a function when a "reset" message (without arguments) appears on the first inlet */ + class_addmethod(counter_class, + (t_method)counter_reset, gensym("reset"), 0); + + /* call a function when a "set" message with one float-argument (defaults to 0) + * appears on the first inlet */ + class_addmethod(counter_class, + (t_method)counter_set, gensym("set"), + A_DEFFLOAT, 0); + + /* call a function when a "bound" message with 2 float-argument (both default to 0) + * appears on the first inlet + * this is used for "list" messages which appear on the 2nd inlet + * the magic is done in counter_new() + */ + class_addmethod(counter_class, + (t_method)counter_bound, gensym("bound"), + A_DEFFLOAT, A_DEFFLOAT, 0); + + /* set the name of the help-patch to "help-counter"(.pd) */ + class_sethelpsymbol(counter_class, gensym("help-counter")); +} -- cgit v1.2.1