Gravity is not applied with Box2D for Flash (v2.1a) - actionscript-3

Question

I am trying to follow a couple of tutorials on Box2D, but somehow I can't seem to get the gravity to be applied. Below is my code (with the URLs that I read for tutorials), maybe there is something I overlooked? Thanks for your help!
package
{
import Box2D.Collision.Shapes.b2PolygonShape;
import Box2D.Common.Math.b2Vec2;
import Box2D.Dynamics.b2Body;
import Box2D.Dynamics.b2BodyDef;
import Box2D.Dynamics.b2DebugDraw;
import Box2D.Dynamics.b2FixtureDef;
import Box2D.Dynamics.b2World;
import org.osflash.signals.natives.NativeSignal;
import flash.display.Sprite;
import flash.display.StageAlign;
import flash.display.StageScaleMode;
import flash.events.Event;
/*
* http://active.tutsplus.com/tutorials/games/introduction-to-box2d-for-flash-and-as3/
* http://blog.allanbishop.com/box2d-2-1a-tutorial-part-1/
* http://plasticsturgeon.com/2010/08/making-an-as3-game-in-box2d-flash-version-2-0-hello-world-box2d/
*/
[SWF(backgroundColor="#cccccc", frameRate="30", width="1280", height="720")]
public class Floor extends Sprite
{
private const WIDTH :uint = 1280;
private const HEIGHT :uint = 720;
private const FPS :uint = 30;
private const NUM_PIXELS_PER_METER :uint = 30;
private const TIMESTEP :Number = 0 / NUM_PIXELS_PER_METER;
private const VELOCITY_ITERATIONS :uint = 6;
private const POSITION_ITERATIONS :uint = 2;
private var _world :b2World;
private var _gravity :b2Vec2;
private var _updated :NativeSignal;
public function Floor()
{
init();
}
private function init():void
{
initStage();
initBox2D();
_updated = new NativeSignal ( this,
Event.ENTER_FRAME,
Event
);
_updated.add(onUpdated);
}
private function initStage():void
{
stage.frameRate = FPS;
stage.align = StageAlign.TOP_LEFT;
stage.scaleMode = StageScaleMode.NO_SCALE;
}
private function initBox2D():void
{
_gravity = new b2Vec2(0, 10);
_world = new b2World(_gravity, true);
var vector:b2Vec2 = new b2Vec2();
// floor
vector.x = (WIDTH * 0.5) / NUM_PIXELS_PER_METER;
vector.y = (HEIGHT * 0.75) / NUM_PIXELS_PER_METER;
var floorBodyDef:b2BodyDef = new b2BodyDef();
floorBodyDef.position.Set(vector.x, vector.y);
var floorBody:b2Body = _world.CreateBody(floorBodyDef);
vector.x = (WIDTH * 0.5) / NUM_PIXELS_PER_METER;
vector.y = 32 / NUM_PIXELS_PER_METER;
var floorBox:b2PolygonShape = new b2PolygonShape();
floorBox.SetAsBox(vector.x, vector.y);
var floorFixture:b2FixtureDef = new b2FixtureDef();
floorFixture.shape = floorBox;
floorFixture.density = 1;
floorFixture.friction = 1;
floorBody.CreateFixture(floorFixture);
// box
vector.x = (WIDTH * 0.5) / NUM_PIXELS_PER_METER;
vector.y = (HEIGHT * 0.125) / NUM_PIXELS_PER_METER;
var boxBodyDef:b2BodyDef = new b2BodyDef();
boxBodyDef.type = b2Body.b2_dynamicBody;
boxBodyDef.position.Set(vector.x, vector.y);
var boxBody:b2Body = _world.CreateBody(boxBodyDef);
var box:b2PolygonShape = new b2PolygonShape();
box.SetAsBox(1, 1);
var boxFixtureDef:b2FixtureDef = new b2FixtureDef();
boxFixtureDef.shape = box;
boxFixtureDef.density = 1;
boxFixtureDef.friction = 0.3;
boxFixtureDef.restitution = 0.1;
boxBody.CreateFixture(boxFixtureDef);
// debug
var debug:Sprite = new Sprite();
addChild(debug);
var debugDraw:b2DebugDraw = new b2DebugDraw();
debugDraw.SetSprite(debug);
debugDraw.SetDrawScale(NUM_PIXELS_PER_METER);
debugDraw.SetLineThickness(1.0);
debugDraw.SetAlpha(1);
debugDraw.SetFillAlpha(0.4);
debugDraw.SetFlags(b2DebugDraw.e_shapeBit);
_world.SetDebugDraw(debugDraw);
}
private function onUpdated(_:Event):void
{
_world.Step ( TIMESTEP,
VELOCITY_ITERATIONS,
POSITION_ITERATIONS
);
_world.ClearForces();
_world.DrawDebugData();
}
}
}

Answer 1

Sorry for being an idiot, when copying the TIMESTEP constant from elsewhere, I got a result of 0... My bad.