Create a MovieClip out of another object - actionscript-3

Question

In my Actionscript program, I draw a polygon using the methods:
this.graphics.moveTo()
and
this.graphics.lineTo()
In the update function of the polygon model I change it a bit, and then draw it all over again. Eventually, every call to the update() function draws the updated polygon and I can see it changes.
On some point of the program, I want to be able to use this polygon as a movieclip, so I
can attach a mask to it - so as the polygon drawn over and over again, I could see a nice
background in the form of that polygon, fills it inside.
Problem is - I do not know how to take this array of points I have, which is my polygon representation, and turn it into a movieclip ( if possible at all... )
If you have any other recommendations how to implement the above, It would be great.

Answer 1

You can just create a new MovieClip and use it's graphics for drawing. So instead of using this.graphics.moveTo / lineTo, try this:
var mc:MovieClip = new MovieClip();
mc.graphics.moveTo(...);
mc.graphics.lineTo(...);
this.addChild(mc);
A convenient way of drawing, if you want to type less, is to do something like this:
var mc:MovieClip = new MovieClip();
with(mc.graphics) {
clear();
lineStyle(...);
moveTo(...);
lineTo(...);
...
ect.
}
this.addChild(mc);

Answer 2

I suggest you take a look at Point class. For example,
var p1:Point = new Point(100,150);
Then you can have an array of points
var arrPoints:Array = new Array(p1,p2,p3);
With a for loop, you can decide if i==0 you use moveTo and for the rest use lineTo. You can have a special condition at the end to close your polygon, i==arrPoints.length-1.
So, basically create a movieclip object, use its graphic property to fill it with the points you defined in your array. As long as your points are in a movieclip, you can mask it. Finally, that "this" notation you used is probably referring to the main movieclip which is the stage.
var mc:MovieClip = new MovieClip();
mc.graphics.moveTo(p1.x,p1.y);
will draw your graphics into your mc.