Creation of a Flash Stabilize! clone using Box2D – part 2

package {
	import flash.display.Sprite;
	import flash.events.Event;
	import flash.events.MouseEvent;
	import Box2D.Dynamics.*;
	import Box2D.Collision.*;
	import Box2D.Collision.Shapes.*;
	import Box2D.Common.Math.*;
	public class stabilize extends Sprite {
		public var m_sprite: Sprite = new Sprite();
		public var m_world:b2World;
		// the_crate is the crate sprite
		public var the_crate:crate=new crate();
		// droppable_area is the sprite representing the area your mouse
		// must overlap to drop a crate
		public var droppable_area:drop_area = new drop_area();
		public function stabilize() {
			var gravity:b2Vec2=new b2Vec2(0,9.8);
			var worldAABB:b2AABB = new b2AABB();
			worldAABB.lowerBound.Set(-1000,-1000);
			worldAABB.upperBound.Set(1000,1000);
			m_world=new b2World(worldAABB,gravity,true);
			m_sprite = new Sprite();
			addChild(m_sprite);
			addChild(droppable_area);
			addChild(the_crate);
			debug_draw();
			AddBox(250/30,350/30,10/30,10/30,0,false);
			AddBox(250/30,350/30,200/30,10/30,20,false);
			addEventListener(Event.ENTER_FRAME,Update);
			stage.addEventListener(MouseEvent.MOUSE_DOWN,mousePressed);
			stage.addEventListener(MouseEvent.MOUSE_MOVE,mouseMoved);
		}
		public function mousePressed(e:MouseEvent) {
			// look at hitTestPoint... the final true value says it's going to to check against the actual pixels
			// instead of the bounding box
			if (droppable_area.hitTestPoint(mouseX,mouseY,true)) {
				AddBox(mouseX/30,mouseY/30,0.5,0.5,3,true);
			}
		}
		public function mouseMoved(e:MouseEvent) {
			the_crate.x=mouseX;
			the_crate.y=mouseY;
			if (droppable_area.hitTestPoint(mouseX,mouseY,true)) {
				the_crate.alpha=1;
			} else {
				the_crate.alpha=0.5;
			}
		}
		// function AddBox
		// px: x position
		// py: y position
		// _halfwidth: half of the box width
		// _halfheight: half of the box height
		// density: density of the box (0: static)
		// is_crate: if true, it's a crate (and you should render the proper movieclip
		public function AddBox(px:Number,py:Number,_halfwidth:Number,_halfheight:Number,density:Number,is_crate:Boolean) {
			var bodyDef:b2BodyDef = new b2BodyDef();
			bodyDef.position.Set(px,py);
			var boxDef:b2PolygonDef = new b2PolygonDef();
			boxDef.SetAsBox(_halfwidth,_halfheight);
			boxDef.density=density;
			boxDef.friction=0.3;
			boxDef.restitution=0.2;
			if (is_crate) {
				bodyDef.userData = new crate();
			}
			var body:b2Body=m_world.CreateBody(bodyDef);
			body.CreateShape(boxDef);
			body.SetMassFromShapes();
			if (is_crate) {
				addChild(bodyDef.userData);
			}
		}
		public function Update(e:Event) {
			m_world.Step(1/30,10);
			for (var bb:b2Body = m_world.m_bodyList; bb; bb = bb.m_next) {
				if (bb.m_userData is Sprite) {
					bb.m_userData.x=bb.GetPosition().x*30;
					bb.m_userData.y=bb.GetPosition().y*30;
					bb.m_userData.rotation = bb.GetAngle() * (180/Math.PI);
				}
			}
		}
		public function debug_draw() {
			var dbgDraw:b2DebugDraw = new b2DebugDraw();
			var dbgSprite:Sprite = new Sprite();
			m_sprite.addChild(dbgSprite);
			dbgDraw.m_sprite=m_sprite;
			dbgDraw.m_drawScale=30;
			dbgDraw.m_alpha=1;
			dbgDraw.m_fillAlpha=0.5;
			dbgDraw.m_lineThickness=1;
			dbgDraw.m_drawFlags=b2DebugDraw.e_shapeBit;
			m_world.SetDebugDraw(dbgDraw);
 
		}
	}
}