C sin wave equation in PD

/*compiled on ubuntu 10.04 Linux*/
#include "m_pd.h"
#include "math.h"

#define PI 3.14159265358979323846
#define deg2rad(deg) ((deg * PI) / 180.0)
#define rad2deg(rad) ((180.0 * rad) / PI)



static t_class *sineq_tilde_class;

typedef struct _sineq_tilde
{
    t_object x_obj;
    t_float amp;    /*amplitude*/
    t_float freq;   /*frequency*/
    t_sample f_sineq;
    t_float f;
    t_float phase;  /*phase in radians*/
    t_float vertoff;    /*vertical offset*/

} t_sineq_tilde;

void *sineq_tilde_new(t_floatarg f)
{
    t_sineq_tilde *x =(t_sineq_tilde *)pd_new(sineq_tilde_class);
    x->f_sineq = f;

    inlet_new(&x->x_obj, &x->x_obj.ob_pd, &s_float, &s_float);
    floatinlet_new(&x->x_obj, &x->amp);
    floatinlet_new(&x->x_obj, &x->freq);
    floatinlet_new(&x->x_obj, &x->phase);
    floatinlet_new(&x->x_obj, &x->vertoff);

    x->amp = 0;
    x->freq = 0;
    x->phase = 0;
    x->vertoff = 0;

    outlet_new(&x->x_obj, gensym("signal"));
    return (void *)x;

}

t_int *sineq_tilde_perform(t_int *w)
{
    t_sineq_tilde *x    = (t_sineq_tilde *)(w[1]);
    t_float         *in1 =      (t_float *)(w[2]);
    t_float         *in2 =      (t_float *)(w[3]);
    t_float         *in3 =      (t_float *)(w[4]);
    t_float         *in4 =      (t_float *)(w[5]);
    t_sample        *out =      (t_sample *)(w[6]);
    int                 n =     (int)       (w[7]);

    /*not sure how to implement the t value here*/
    /*t_sample f_sineq =     y=amp*sin(freq*time+phase)+vertoff */
    while (n--)
    {
        float amp=w[2];
        float freq=w[3];
        float phase=w[4];
        float vertoff=w[5];
        *out++ = amp*sin(2*PI*freq+(deg2rad(phase)))+vertoff;
    }
    return (w+8);
}

void sineq_tilde_dsp(t_sineq_tilde *x, t_signal **sp)
{
    dsp_add(sineq_tilde_perform, 7, x,
        sp[0]->s_vec, sp[1]->s_vec, sp[2]->s_vec, sp[3]->s_vec,
        sp[4]->s_vec, sp[0]->s_n);
}

void sineq_tilde_setup(void)
{
    sineq_tilde_class = class_new(gensym("sineq~"),
        (t_newmethod)sineq_tilde_new, 0,
        sizeof(t_sineq_tilde), 0,
        A_DEFFLOAT, 0);
    class_addmethod(sineq_tilde_class,
        (t_method)sineq_tilde_dsp, gensym("dsp"), 0);
    CLASS_MAINSIGNALIN(sineq_tilde_class,t_sineq_tilde, f);
}