AS3 collision detection in an object itself - actionscript-3

Question

I´m programing a space ship side scroll in as3. The bottom of the stage are mountains and here comes the problem, when I try to detect the ship collision against the mountains..
Because the poor collision detection and the need of avoid large loops my idea is create an object that works as a collider itself detecting a collision and avoiding parse all the stage or more selective metod.
I place "by hand" in the flash stage several instances of circles with a class for manage them where I place the If(this.collider.hits(ship)....
I spent looong time but I can find the way to make it work some of the mistakes i get are like this
Error 1061: Call to a possibly undefined method hitTestObject through a reference with static type Class.
some Idea? Thanks in advance

Answer 1

when you hit test with points it is important that the point being tested is relative to the object being tested against, eg
if(mountain.hitTestPoint(this.x + circle1.x, this.y + circle1.y))
will return true if the circles are inside the object calling the function because their position relative to the mountain is now relative to it rather then relative to the ships xy position within the clip... hope that makes sense.
btw I have done this myself in the past but I would have to remind you that you can only hit test with the points so there is no need to have circles, use blank sprites instead and set the visible flag in the properties panel to false, no drawing will make it slightly faster... not that you will notice, also sprites/graphics use less memory then movie clips.
also I would recommend hard coding some points in the clips rather then actually adding the clips in the sprite/clip itself, this will make it easier to work with them and scale later on (believe me this will annoy the hair from your head to do something later and slow the game to scale on the fly)
try something like this... you can determine the points values by adding a clip to the movie clip and getting its position from the properties if you must.
private var hitPoints:Vector.<Point> = new Vector.<Point>
hitPoints.push(new Point(10, 40));
hitPoints.push(new Point(30, 40));
//...do this for all your points
//loop through all your points and check if the hit relative to the ships position.
for(var i:int = 0; i < hitPoints.length; i++)
{
if (scene.hitTestPoint(ship.x + hitPoints[i].x, ship.y + hitPoints[i].y))
{
//do your hit stuff here
break;//don't forget to break
}
}
in this code you will need to make sure the scene object is a reference to your scenery at the bottom of the screen.
I hope this helps but if this is not enough help then you should post some of your code here so we can have a look and see where it can be improved.