Box2D入门第一天

开始学习Box2d，今天是第一天，上班好累的时候试着弄了弄Box2D，包括：

1 创建世界

2 创建debugdraw

3 创建一个简单的盒子

其中有很多东西不甚明了，

贴上代码如下以备忘：

package
{
	/**
	 * @create_time Apr 13, 2012 4:00:54 PM
	 * @author Ado
	 * @E-mail: adodo08@163.com
	 **/
	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 flash.display.Sprite;
	import flash.events.Event;
	import flash.events.MouseEvent;
	[SWF(width=1000,height=600,frameRate=24,backgroundColor=0xcccccc)]
	public class BoxTester extends Sprite
	{
		private var world:b2World;
		private var worldSprite:Sprite;
		private var drawScale:Number=20;
		public function BoxTester()
		{
			//创建世界，两个参数：重力与是否睡眠
			world = new b2World(new b2Vec2(0,10),true);
			//调试用的，估计，待研究
			drawDebug();
			addEventListener(Event.ENTER_FRAME, update);
			//让我很奇怪的是为什么监听不到鼠标事件
			addEventListener(MouseEvent.CLICK, generateBody);
		}
		
		private function generateBody(e:MouseEvent=null):void
		{
			//创建一个世界对象的流程，感觉很麻烦的样子，包括各类的数据
			var shape:b2PolygonShape = new b2PolygonShape();
			shape.SetAsBox(10/drawScale,10/drawScale);
			var fixture:b2FixtureDef = new b2FixtureDef();
			fixture.density = 1;
			fixture.friction = 2;
			fixture.restitution = 1;
			fixture.shape = shape;
			var bodyDef:b2BodyDef = new b2BodyDef();
			bodyDef.type = b2Body.b2_dynamicBody;
			bodyDef.position.Set(this.mouseX/drawScale, this.mouseY/drawScale);
			var body:b2Body = world.CreateBody(bodyDef);
			body.CreateFixture(fixture);
		}
		
		private function update(e:Event):void
		{
			world.Step(1/drawScale,10,10);
			world.ClearForces();
			world.DrawDebugData();
			generateBody();
		}
		private function drawDebug():void
		{
			var debugDraw:b2DebugDraw = new b2DebugDraw();
			var debugSprite:Sprite = new Sprite();
			addChild(debugSprite);//讲debugdraw的关联视图添加到舞台上
			debugDraw.SetSprite(debugSprite);//关联sprite到debugdraw
			debugDraw.SetDrawScale(drawScale);//设置debugdraw的比例
			debugDraw.SetFlags(b2DebugDraw.e_shapeBit|b2DebugDraw.e_jointBit);//？
			debugDraw.SetFillAlpha(0.5);//设置背景填充透明度
			world.SetDebugDraw(debugDraw);//关联世界
		}
	}
}