Flash as making snow animation effect

Use pure flash ActionScript to achieve the snow animation effect.

Effect Demo:

Click here to download the source file (Decompression password: www.webjx.com)

The way to do this is to put the following code directly into the 1th frame of the newly created flash document:

function Addmasker ()
{
_root.createemptymovieclip ("Masker",-2);
With (Masker)
{
LineStyle (1, 13421772, 100);
Beginfill (0, 100);
MoveTo (Sidediswidth, sidedisheight);
LineTo (Sidediswidth + scenewidth, sidedisheight);
LineTo (Sidediswidth + scenewidth, sidedisheight + sceneheight);
LineTo (sidediswidth, sidedisheight + sceneheight);
Endfill ();
}//End of With
Createsnow ();
}//End of the function
function Createsnow ()
{
var _l1 = 0;
while (_l1 < snownum)
{
var _l2 = Snowspace.createemptymovieclip ("s" + _L1, _L1);
var _l3 = Math.random () * 3;
Drawsnow (_L2, _L3);
_l1++;
}//End While
}//End of the function
function Drawsnow (snow, radius)
{
var p = radius * 0.900000;
With (Snow)
{
colors = [13421772, 16777215];
Alphas = [100, 100];
Ratios = [0, 255];
Matrix = {matrixtype: "box", X:-math.random () * 2 * radius, Y:-math.random () * 2 * radius, W:2 * radius, H:2 * radius, r:1.570796};
Begingradientfill ("Radial", colors, alphas, ratios, matrix);
Curveto (p, p, radius, 0);
Curveto (p, p, 0, RADIUS);
Curveto (-P, p,-radius, 0);
Curveto (p, p, 0,-radius);
Endfill ();
}//End of With
Snowproperty (Snow, scenewidth, sceneheight);
}//End of the function
function Snowproperty (Snow, W, h)
{
snow._x = Sidediswidth + math.random () * W;
snow._y = Sidedisheight + math.random () * H;
Snow._rotation = Math.random () * 120 + 30;
snow.stepx = Math.Cos (snow._rotation * 3.141593/180);
Snow.stepy = Math.random () * 2 + 1;
SetInterval (snowfall, snow);
}//End of the function
Function snowfall (snow)
{
snow._x = snow._x + snow.stepx;
snow._y = snow._y + snow.stepy;
if (Sidediswidth > Snow._x)
{
snow._x = Sidediswidth + scenewidth;
}//End If
if (Sidediswidth + scenewidth < snow._x)
{
snow._x = Sidediswidth;
}//End If
if (Sidedisheight + sceneheight < snow._y)
{
snow._y = Sidedisheight;
}//End If
}//End of the function
var scenewidth = 550;
var sceneheight = 400;
var sidediswidth = stage.width/2-SCENEWIDTH/2;
var sidedisheight = stage.height/2-SCENEHEIGHT/2;
var snownum = 150;
var snowspace = _root.createemptymovieclip ("Room", 1);
Addmasker ();