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/* rcosc~.c by Martin Peach 20100331 */
/* Pd external emulating a resistor-capacitor-controlled oscillator */
/* The first control parameter is a time constant in seconds (or resistance X capacitance) */
/* The second control parameter is a threshold above which the cap is set to discharge */
/* The third control parameter is a threshold below which the cap is set to charge */
#include "m_pd.h"
static t_class *rcosc_tilde_class;
typedef struct _rcosc_tilde
{
t_object rc_obj;
t_float rc_f;
t_float rc_upper_threshold; /* if rc_dir is 1, charge to here */
t_float rc_lower_threshold; /* if rc_dir is 0, discharge to here */
t_int rc_dir;
double rc_node;
double rc_one;
double rc_zero;
double rc_sp;
double rc_slewmax;
} t_rcosc_tilde;
static t_int *rcosc_tilde_perform(t_int *w);
static void rcosc_tilde_dsp(t_rcosc_tilde *x, t_signal **sp);
static void *rcosc_tilde_new(t_floatarg f);
static t_int *rcosc_tilde_perform(t_int *w)
{
t_rcosc_tilde *x = (t_rcosc_tilde *)(w[1]);
t_sample *in = (t_sample *)(w[2]);
t_sample *out = (t_sample *)(w[3]);
int n = (int)(w[4]);
double slewrate, delta, node, overshoot;
int i, n_oversamples = 64;
// if (x->rc_rc < x->rc_sp) slewrate = 1.0;
// else slewrate = x->rc_sp/x->rc_rc;
while (n--)
{
slewrate = x->rc_one/(n_oversamples*(x->rc_sp*(*in++)));
if (slewrate < x->rc_zero) slewrate = x->rc_zero;
else if (slewrate > x->rc_one) slewrate = x->rc_one;
node = x->rc_node;
for (i = 0; i < n_oversamples; ++i)
{
if (x->rc_dir)
{
delta = slewrate*(x->rc_one - x->rc_node);
if (delta > x->rc_slewmax) delta = x->rc_slewmax;
x->rc_node += delta;
overshoot = x->rc_node - x->rc_upper_threshold;
if (overshoot > 0)
{
x->rc_dir = 0;
x->rc_node = x->rc_upper_threshold - overshoot; /* bounce */
}
}
else
{
delta = slewrate*(x->rc_zero - x->rc_node);
if (delta < -x->rc_slewmax) delta = -x->rc_slewmax;
x->rc_node += delta;
overshoot = x->rc_lower_threshold - x->rc_node;
if (overshoot > 0)
{
x->rc_dir = 1;
x->rc_node = x->rc_lower_threshold + overshoot; /* bounce */
}
}
}
*out++ = ((node + x->rc_node)*3)-3;
}
return (w+5);
}
static void rcosc_tilde_dsp(t_rcosc_tilde *x, t_signal **sp)
{
x->rc_sp = sys_getsr();
dsp_add(rcosc_tilde_perform, 4, x, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);
}
static void *rcosc_tilde_new(t_floatarg f)
{
t_rcosc_tilde *x = (t_rcosc_tilde *)pd_new(rcosc_tilde_class);
x->rc_f = f;
x->rc_node = 0.0;
x->rc_upper_threshold = 0.666; /* if rc_dir is 1, charge to here */
x->rc_lower_threshold = 0.333; /* if rc_dir is 0, discharge to here */
x->rc_slewmax = 0.003;/* arbitrary slew rate limit */
x->rc_dir = 1; /* start charging */
x->rc_one = 1;
x->rc_zero = 0;
outlet_new(&x->rc_obj, &s_signal);
post("rcosc~ 20100331 Martin Peach");
return (void *)x;
}
void rcosc_tilde_setup(void)
{
rcosc_tilde_class = class_new(gensym("rcosc~"),
(t_newmethod)rcosc_tilde_new,
0, sizeof(t_rcosc_tilde),
CLASS_DEFAULT,
A_DEFFLOAT, 0);
class_addmethod(rcosc_tilde_class, (t_method)rcosc_tilde_dsp, gensym("dsp"), 0);
CLASS_MAINSIGNALIN(rcosc_tilde_class, t_rcosc_tilde, rc_f);
}
/* fin rcosc~.c */
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