How to make a snow mask in ActionScript 2?

Question

ActionScript

Hello, there is a script that generates snowflakes:

for(i=0; i<1000; i++)
{
var t:MovieClip = snow_mc.duplicateMovieClip("snow"+i,i);
t._x = random(750);
t._y = random(550);
t._xscale = t._yscale = random(80)+20;
t.gotoAndPlay(Math.round(random(81)+1));
}

The task is to make the snowflakes be under the mask, that is, the background of the picture wakes up (the ball in which it is snowing).
if you add a mask called mask_mc :
_root.setMask(mask_mc);
then the mask cuts out all layers and the background too, but you need the mask to cut out only the snow...

Answer 1

And if the mask is not installed inside the root root?