Box2DのサンプルをFlexで動かしてみた。

Box2Dを久しぶりに触ってみました。
っと言っても、うまくいったためしがなかったので、チャレンジです。
実際の動作はこちら
http://moeten.info/flex/20080424_box2DTest1/bin-release/main.html

ソースはこちら
サンプルソースをFlex用に手直ししてます。
今回はImageコンポーネントにaddchildのがミソです。
Papervision3Dもそうだけど、this.addchildだとエラーが起きる場合はImageコンポーネントにaddchildすればほとんどＯＫ。
なぜそうなのかはわかりません＼(-o-)／

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" creationComplete="init()" viewSourceURL="srcview/index.html">
<mx:Script>
<![CDATA[
import flash.display.Sprite;
import flash.events.Event;
import Box2D.Dynamics.*;
import Box2D.Collision.*;
import Box2D.Collision.Shapes.*;
import Box2D.Common.Math.*;
public var m_world:b2World;
public var m_iterations:int = 10;
public var m_timeStep:Number = 1.0/30.0;
[Embed(source='PhysGround.swf')]
private static var PhysGround:Class;
[Embed(source='PhysBox.swf')]
private static var PhysBox:Class;
[Embed(source='PhysCircle.swf')]
private static var PhysCircle:Class;
private function init():void{
    // Add event for main loop
    this.addEventListener(Event.ENTER_FRAME, Update, false, 0, true);
    // Creat world AABB
    var worldAABB:b2AABB = new b2AABB();
    worldAABB.lowerBound.Set(-100.0, -100.0);
    worldAABB.upperBound.Set(100.0, 100.0);
    // Define the gravity vector
    var gravity:b2Vec2 = new b2Vec2(0.0, 10.0);
    // Allow bodies to sleep
    var doSleep:Boolean = true;
    // Construct a world object
    m_world = new b2World(worldAABB, gravity, doSleep);
    // set debug draw
    /*var dbgDraw:b2DebugDraw = new b2DebugDraw();
    var dbgSprite:Sprite = new Sprite();
    addChild(dbgSprite);
    dbgDraw.m_sprite = dbgSprite;
    dbgDraw.m_drawScale = 30.0;
    dbgDraw.m_fillAlpha = 0.0;
    dbgDraw.m_lineThickness = 1.0;
    dbgDraw.m_drawFlags = 0xFFFFFFFF;
    m_world.SetDebugDraw(dbgDraw);*/
    // Vars used to create bodies
    var body:b2Body;
    var bodyDef:b2BodyDef;
    var boxDef:b2PolygonDef;
    var circleDef:b2CircleDef;
    // Add ground body
    bodyDef = new b2BodyDef();
    //bodyDef.position.Set(15, 19);
    bodyDef.position.Set(10, 12);
    //bodyDef.angle = 0.1;
    boxDef = new b2PolygonDef();
    boxDef.SetAsBox(30, 3);
    boxDef.friction = 0.3;
    /*circleDef = new b2CircleDef();
    circleDef.radius = 10;
    circleDef.restitution = 0.2*/
    // Add sprite to body userData
    bodyDef.userData = new PhysGround();
    bodyDef.userData.width = 30 * 2 * 30;
    bodyDef.userData.height = 30 * 2 * 3;
    myImage.addChild(bodyDef.userData);
    body = m_world.CreateStaticBody(bodyDef);
    body.CreateShape(boxDef);
    //body.CreateShape(circleDef);
    body.SetMassFromShapes();
    // Add some objects
    for (var i:int = 1; i < 10; i++){
        bodyDef = new b2BodyDef();
        bodyDef.position.x = Math.random() * 15 + 5;
        bodyDef.position.y = Math.random() * 10;
        var rX:Number = Math.random() + 0.5;
        var rY:Number = Math.random() + 0.5;
        // Box
        if (Math.random() < 0.5){
            boxDef = new b2PolygonDef();
            boxDef.SetAsBox(rX, rY);
            boxDef.density = 1.0;
            boxDef.friction = 0.5;
            boxDef.restitution = 0.2;
            bodyDef.userData = new PhysBox();
            bodyDef.userData.width = rX * 2 * 30;
            bodyDef.userData.height = rY * 2 * 30;
            body = m_world.CreateDynamicBody(bodyDef);
            body.CreateShape(boxDef);
        }
        // Circle
        else {
            circleDef = new b2CircleDef();
            circleDef.radius = rX;
            circleDef.density = 1.0;
            circleDef.friction = 0.5;
            circleDef.restitution = 0.2
            bodyDef.userData = new PhysCircle();
            bodyDef.userData.width = rX * 2 * 30;
            bodyDef.userData.height = rX * 2 * 30;
            body = m_world.CreateDynamicBody(bodyDef);
            body.CreateShape(circleDef);
        }
        body.SetMassFromShapes();
        myImage.addChild(bodyDef.userData);
    }
}
public function Update(e:Event):void{
    m_world.Step(m_timeStep, m_iterations);
    // Go through body list and update sprite positions/rotations
    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);
        }
    }
}
]]>
</mx:Script>
<mx:Image id="myImage"  x="0" y="0" width="634" height="596"/>
</mx:Application>