package
{
         import Box2D.Collision.b2Bound;
         import Box2D.Dynamics.b2World;
         import Box2D.Common.Math.b2Vec2;
         import Box2D.Dynamics.b2BodyDef;
         import Box2D.Dynamics.b2Body;
         import Box2D.Collision.Shapes.b2PolygonShape;
         import Box2D.Dynamics.b2Fixture;
         import Box2D.Dynamics.b2FixtureDef;
         import Box2D.Dynamics.b2DebugDraw;
         import flash.display.MovieClip;
         import flash.display.Sprite;
         import flash.events.Event;
         
         [SWF(width = "800", height = "600", backgroundColor="#fafed6", frameRate = "30")]

         public class Main extends MovieClip
         {
              private const PIXELS_TO_METRE:int = 30;
              private const SWF_HALF_WIDTH:int = 400;
              private const SWF_HEIGHT:int = 600;
              private var _world:b2World;
          
              public function Main()
              {
                   // создаем мир
                   _world = new b2World(new b2Vec2(0, 10), true);

// создаем свойства тела
var groundBodyDef:b2BodyDef = new b2BodyDef();
groundBodyDef.position.Set(SWF_HALF_WIDTH / PIXELS_TO_METRE,     
                    SWF_HEIGHT / PIXELS_TO_METRE-20 / PIXELS_TO_METRE);

// добавляем тело к миру
var groundBody:b2Body = _world.CreateBody(groundBodyDef);

// создаем форму (shape)
var groundBox:b2PolygonShape = new b2PolygonShape();
groundBox.SetAsBox(SWF_HALF_WIDTH / PIXELS_TO_METRE, 20 / PIXELS_TO_METRE);

// устанавливаем свойства тела
var groundFixtureDef:b2FixtureDef = new b2FixtureDef();
groundFixtureDef.shape = groundBox; // форма
groundFixtureDef.density = 1;       // плотность
groundFixtureDef.friction = 1;      // трение
groundBody.CreateFixture(groundFixtureDef);

// создаем динамическое тело
var bodyDef:b2BodyDef = new b2BodyDef();
bodyDef.type = b2Body.b2_dynamicBody;    // тело будет динамическим
bodyDef.position.Set(SWF_HALF_WIDTH / PIXELS_TO_METRE, 4);
var body:b2Body = _world.CreateBody(bodyDef);
           
var dynamicBox:b2PolygonShape = new b2PolygonShape();
dynamicBox.SetAsBox(1, 1);
           
var fixtureDef:b2FixtureDef = new b2FixtureDef();
fixtureDef.shape = dynamicBox;
fixtureDef.density = 1;
fixtureDef.friction = 0.3;
           
body.CreateFixture(fixtureDef);

// отображаем все на экране
var debugSprite:Sprite = new Sprite();
addChild(debugSprite);
var debugDraw:b2DebugDraw = new b2DebugDraw();
debugDraw.SetSprite(debugSprite);
debugDraw.SetDrawScale(PIXELS_TO_METRE);
debugDraw.SetLineThickness(1.0);
debugDraw.SetAlpha(1);
debugDraw.SetFillAlpha(0.4);
debugDraw.SetFlags(b2DebugDraw.e_shapeBit);
_world.SetDebugDraw(debugDraw);

// добавляем слушателя
addEventListener(Event.ENTER_FRAME, update);

public function update(e:Event):void
{
       var timeStep:Number = 1 / 30;
       var velocityIterations:int = 6;
       var positionIterations:int = 2;
           
       _world.Step(timeStep, velocityIterations, positionIterations);

_world.ClearForces();

// отрисовываем
_world.DrawDebugData();