gfx_init("vis",1024,768);

zp=-0.84;
fill=0;
radj=1;
while ((c=gfx_getchar())!=27 && c >= 0)
(
  c == 'f' ? fill=!fill;
  c == 'j' ? jitter=!jitter;
  c == 'm' ? radj = !radj;

  gfx_r=gfx_g=gfx_b=1;
  gfx_a=1;
  gfx_x=gfx_y=0;
  gfx_printf("[f]ill=%s, [j]itter=%s, [m]ove=%s [%f] %d,%d",fill?"on":"off",jitter?"on":"off",radj?"on":"off",zp,mouse_x,mouse_y);
  gfx_a=0.25;


  radj ? zp+=0.03;
  gfx_getchar('up') ? zp+=0.03;
  gfx_getchar('down') ? zp-=0.03;
  zp2+=0.1; 
  rd = (1+sin(zp*1.3))*(gfx_w/8-16) + 3;
  jitter ? (  
    xoffs=0.5+sin(zp2*6.7)*0.5;
    yoffs=0.5+sin(zp2*7.7)*0.5;
    rd|=0;
    rd += 0.5+sin(zp2*3.1)*0.5
  ) : ( xoffs=yoffs=0; rd|= 0;);


  gfx_circle(xoffs+(gfx_w/4)|0,yoffs+(gfx_h/2)|0,rd, fill,0);
  gfx_circle(xoffs+(gfx_w*3/4)|0,yoffs+(gfx_h/2)|0,rd, fill,1);

  gfx_mode=4+(1<<4); // filtering off, additive
  gfx_a=1;
  zsz=20;
  outsz=gfx_w/4;
  gfx_blit(-1,0,0,
        gfx_w/4-zsz, gfx_h/2-zsz, zsz*2,zsz*2, 
        0,gfx_h-outsz,outsz,outsz);

  gfx_blit(-1,0,0,
        gfx_w*3/4-zsz, gfx_h/2-zsz, zsz*2,zsz*2, 
        gfx_w-outsz,gfx_h-outsz,outsz,outsz);
  gfx_mode=0;

  gfx_update();
  sleep(30);
);