Space Invaders

Hi all,

I have had a little space invaders type game on the go for a while and had some free time so I thought I'd have a blast at finishing it. I have a function checking every frame whether the passed instance hits another movieclip (one of around twenty that it could hit) using onEnterFrame, a for loop to go through the different movieclips and hitTest().

The problem is this function is itself being called several times at once (its a missile that launches on pressing the space bar) so I very quickly end up with the for loop running every frame on several different instances. (I think) this causes a huge slowdown where it pretty much grinds to a halt. There are many more complex games out than mine so I assume it must be my crappy coding :o - Does anyone have any suggestions?

here is the code

stop ();

/* Control variables for use in functions */
var missileDuplicate:MovieClip; //name of the most current missile (set dynamically)
var bombDuplicate:MovieClip; // name of the most current bomb (set dynamically)
var j:Number = 3; //used to increment missile name
var k:Number = 1; //used to increment bomb name
var intervalId:Number; //counter for setInterval
var keyListener:Object = new Object ();

/*Difficulty variables eventually set automatically */
var distance:Number = 5; //speed of ship
var missileNum:Number = 200; //maximum missiles
var bombNum:Number; //number of bombs this level
var bombFreq:Number; //frequency of bombs
var bombSpeed:Number; //not used yet
var bombDiff:Number; //not used yet

bombNum = 10;
bombFreq = 3000;
bombDiff = 2;


/* setting up thew stage */
this.createEmptyMovieClip ("parent_mc", 0);

parent_mc.attachMovie ("missile_mc", "missile_mc", 2, {_x:250, _y:392});
parent_mc.missile_mc.stop ();
parent_mc.missile_mc._visible = false;

parent_mc.attachMovie ("bomb_mc", "bomb_mc", 1, {_x:250});
parent_mc.bomb_mc.stop ();
parent_mc.bomb_mc._visible = false;

missiles_txt.text = missileNum; //counts down the number of missiles left


/* Bomb control functions */
function bombsAway ()
{
var l:Number = missileNum + k;
bombDuplicate = parent_mc.bomb_mc.duplicateMovieClip ("bomb" + k + "_mc", l, {_x:Math.floor (Math.random () * (445 - 0 + 1)) + 0});
bombControl (bombDuplicate);
if (k == bombNum)
{
clearInterval (intervalId);
return;
}
k++;
}
intervalId = setInterval (this, "bombsAway", bombFreq);

function bombControl (missMov:MovieClip)
{
missMov.onEnterFrame = function ()
{
if (missMov.hitTest (base_mc))
{
this.gotoAndStop (2);
}
};
}

/*missile control*/
function hitMe (missMov:MovieClip)
{
missMov.onEnterFrame = function ()
{
if ((missMov.hitTest (blocks.blocks1)) || (missMov.hitTest (blocks.blocks2)) || (missMov.hitTest (blocks.blocks3)))
{
removeMovieClip (missMov);
}
for (var i=1; bombNum; i++){
var mov:MovieClip = MovieClip("parent_mc.bomb"+i+"_mc");

if (missMov.hitTest (mov)){
removeMovieClip(mov);
removeMovieClip(missMov);}}
};
}

/*keypress control */
keyListener.onKeyDown = function ()
{
if (Key.isDown (Key.LEFT))
{
ship_mc._x = Math.max (ship_mc._x - distance, 0);
}
else if (Key.isDown (Key.RIGHT))
{
ship_mc._x = Math.min (ship_mc._x + distance, Stage.width - 120 - ship_mc._width);
}
else if (Key.isDown (Key.SPACE))
{
if (j < missileNum + 3)
{
missileDuplicate = parent_mc.missile_mc.duplicateMovieClip ("missile" + j + "_mc", j);
missileDuplicate._x = ship_mc._x + (ship_mc._width / 2);
missiles_txt.text = missileNum + 2 - j;
j++;
hitMe (missileDuplicate);
}
}
};
Key.addListener (keyListener);


hopefully you can see the bit I'm talking about is in the hitMe function

Any help you could give would be greatly appreciated

Sam