Flash 8 making fireworks particle effects

Special effects Flash View address:
http://www.citydna.cn/works/etboy.asp
Make fireworks particle effects with flash 8
The action code is as follows: (code from FLASH8, now learning, hoho~~)

Stage.scalemode = "Noscale";
Import Flash.display.BitmapData;
Import Flash.filters.ConvolutionFilter;
Import Flash.geom.Rectangle;
var con = new Convolutionfilter (3, 3, [1, 1, 1, 1, 30, 1, 1, 1, 1], 38);
var rect:rectangle = new Rectangle (0, 0, stage.width, 200);
var bitmap1 = new BitmapData (Rect.width, Rect.height, false,0x00000000);
var bitmap2 = new BitmapData (Rect.width, Rect.height, true,0x00000000);
var bitmapShow1 = Createemptymovieclip ("BitmapShow1", 1). Attachbitmap (Bitmap1,
1);
The display canvas of the particle
var bitmapShow2 = Createemptymovieclip ("BitmapShow2", 2). Attachbitmap (BITMAP2,
2);
White sparkle on the display canvas
var m_mousex;
Mouse x coordinates
var M_mousey;
Mouse y coordinates
var sound1 = new Sound ();
The sound of the rising process
var sound2 = new Sound ();
Explosion Sound
var bit_px = new Array (bits);
X-coordinates of the explosion process
var bit_py = new Array (bits);
The y-coordinate of the explosion process
var bit_vx = new Array (bits);
X velocity of the explosion process
var bit_vy = new Array (bits);
The Y-velocity of the explosion process
var bit_sx = new Array (bits);
X-coordinate of the ascent process
var bit_sy = new Array (bits);
The y-coordinate of the ascent process
var bit_l = new Array (bits);
The life time of the particle
var bit_f = new Array (bits);
The sign of a rise or an explosion.
var bit_p = new Array (bits);
Sign of random white sparkle
var bit_c = new Array (bits);
Particle color
Init ();
function init () {
Sound1.attachsound ("Sound1");
Sound2.attachsound ("Sound2");
bits = 500;
The total maximum number of particles
Bit_max = 50;
Number of particles in one occurrence
Bit_sound = 2;
for (var j = 0; j<bits; j + +) {
BIT_F[J] = 0;
}
}
Onenterframe = function () {
Bitmap2.fillrect (New Rectangle (0, 0, Rect.width, rect.height),
0x00000000);
White Sparkle Clear
Bitmap2.applyfilter (Bitmap, Bitmap.rectangle, new Point (0, 0), con);
Rend ();
Bitmap1.applyfilter (Bitmap1, Bitmap1.rectangle, New Point (0, 0), con);
Blur Filter
};
OnMouseDown = function () {
M_mousex = _root._xmouse;
M_mousey = _root._ymouse;
if (Rect.contains (M_mousex, M_mousey)) {
var k = int (math.random () *256);
var l = Int (math.random () *256);
var i1 = Int (math.random () *256);
var J1 = k << 16 | L << 8 | I1;
var k1 = 0;
for (var l1 = 0; l1<bits; l1++) {
if (Bit_f[l1]!= 0) {
Continue
}
BIT_PX[L1] = M_mousex;
BIT_PY[L1] = M_mousey;
var d = math.random () *6.28;
var D1 = Math.random ();
BIT_VX[L1] = Math.sin (d) *d1/2;
BIT_VY[L1] = Math.Cos (d) *d1/2;
BIT_L[L1] = Int (math.random () *100) +100;
BIT_P[L1] = Int (math.random () *3);
if (random (4) = = 0) {
BIT_C[L1] = 0xFFFFFF;
} else {
BIT_C[L1] = J1;
}
BIT_SX[L1] = M_mousex;
BIT_SY[L1] = rect.height-5;
BIT_F[L1] = 2;
if (++k1 = = Bit_max) {
Break
}
}
Sound1.start (0);
}
};
function rend () {
var Flag:boolean = false;
var Flag1:boolean = false;
var Flag2:boolean = false;
for (var k = 0; k<bits; k++) {
Switch (Bit_f[k]) {
Case 1:
Explosion process
BIT_VY[K] + + = math.random ()/100;
Bit_px[k] + = bit_vx[k];
Bit_py[k] + = bit_vy[k];
bit_l[k]--;
if (bit_l[k] = = 0 | |!rect.contains (BIT_PX[K), bit_py
[K])) {
Bit_c[k] = 0x000000;
Bit_f[k] = 0;
else if (bit_p[k] = = 0) {
if (int (math.random () *2) = = 0) {
Bit_setwhite (int (bit_px[k]), int
(Bit_py[k]), 0xFFFFFFFF);
}
Bit_set (int (bit_px[k]), int (bit_py[k]), int
(Bit_c[k]));
} else {
Bit_set (int (bit_px[k]), int (bit_py[k]), int
(Bit_c[k]));
}
Break
Case 2:
Ascent Process
BIT_SY[K]-= 5;
if (Bit_sy[k]<=bit_py[k]) {
Bit_f[k] = 1;
Flag2 = true;
}
if (int (math.random () *20) = = 0) {
var i = Int (math.random () *2);
var j = Int (Math.random () *5);
Bit_set (Bit_sx[k]+i, Bit_sy[k]+j, 0xFFFFFF);
}
Break
}
}
if (Flag2) {
Sound2.start (0);
}
}
function Bit_set (I:number, J:number, K:number) {
Bitmap1.setpixel (I, J, K);
}
function Bit_setwhite (I:number, J:number, K:number) {
Bitmap2.setpixel32 (I, J, K);
White Sparkle
}