#include <math.h>
#include <stdio.h>
#include <stdlib.h>

#include "driver.h"

void tick(void)
{
 int i;
 double x;
 double y;
 int ix;
 int iy;
 int pix;
 int piy;
 unsigned int tv;

 if (npar < 3)
  { printf("need three parameters\n");
    exit(1);
  }
 tv = winh - 1;
 while (tv & (tv + 1)) tv |= tv + 1;
 XSetFunction(disp,bitgc,GXcopy);
 XSetForeground(disp,bitgc,0);
 XFillRectangle(disp,pic,bitgc,0,0,winw,winh);
 XSetForeground(disp,bitgc,1);
 for (i=0;i<=pars[2];i++)
  { x = cos((i*pars[0]*2)*M_PI/pars[2]);
    y = sin((((i*pars[1]*2)*M_PI)+t)/pars[2]);
    ix = ((x+1) * (winw-1)) / 2;
    iy = ((y+1) * (winh-1)) / 2;
    if (i) XDrawLine(disp,pic,bitgc,pix,piy,ix,iy);
    pix = ix;
    piy = iy;
  }
}