aUCBLogo Demos and Tests / pixtest

be pixtest
   cs ht
   setScreenColor 0
;   norefresh
   setUpdateGraph false
   n=1000
   x=Array n
   c=Array n
   repeat n
   [   w=random 360
      r=600*rnd^1.1
      x.repcount=(List  cos w  sin w)*r
      c.repcount=hsb 360*repcount/n  1/4  1
   ]
   ox=x+0   ; to create the same structure as in x, so that we can use xcopy and x+=v
   v=x/100
   i=0
   t=0
   forever
;   repeat 10000000
   [;   t0=timefine
      if key? [stop]
      xcopy "ox x      ; copy only the values (no new nodes are made)
      x+=v         ; dito
      v*=1.02
      repeat n
      [   if (norm x.repcount) > 300
         [   w=random 360
            r=300*rnd^1.1
            x.repcount=(List  cos w  sin w)*r
            v.repcount=x.repcount/100
         ]
      ]
      clean
      setPixel x c
      updateGraph
      gc
   ;   t = (i*t + timefine-t0)/(i+1)
   ;   ct (pr 1/t "frames/sec)
   ;   i+=1
   ]
end