package{

     import Box2D.Collision.b2AABB;

     import Box2D.Collision.b2RayCastInput;

     import Box2D.Collision.b2RayCastOutput;

     import Box2D.Collision.Shapes.b2CircleShape;

     import Box2D.Collision.Shapes.b2PolygonShape;

     import Box2D.Collision.Shapes.b2Shape;

     import Box2D.Common.Math.b2Vec2;

     import Box2D.Dynamics.b2Body;

     import Box2D.Dynamics.b2BodyDef;

     import Box2D.Dynamics.b2Fixture;

     import Box2D.Dynamics.b2FixtureDef;

     import Box2D.Dynamics.b2World;

     import flash.display.Sprite;

     import flash.utils.getTimer;

     import Box2D.Dynamics.Joints.b2PulleyJoint;

     import Box2D.Dynamics.Joints.b2PulleyJointDef;

     /**

     *

     */

     public class Main extends BaseMain{

         public function Main(){

             super(new b2Vec2(0,10));

         }

         override protected function init():void{

             var bodyA:b2Body=this.createBox(50,50,100,400);

             var bodyB:b2Body=this.createCircle(25,700,400);

             var jointDef:b2PulleyJointDef=new b2PulleyJointDef();

             //悬挂的两个点

             var gaA:b2Vec2=new b2Vec2(100/_pixelToMeter,100/_pixelToMeter);

             var gaB:b2Vec2=new b2Vec2(700/_pixelToMeter,100/_pixelToMeter);

             var anchorA:b2Vec2=bodyA.GetWorldCenter();

             var anchorB:b2Vec2=bodyB.GetWorldCenter();

             var r:Number=1;//如果系数是2,那么 length1 的变化会是 length2 的两倍。另外连接 body1 的绳子的约束力将会是连接 body2 绳子的一半。

             jointDef.Initialize(bodyA,bodyB,gaA,gaB,anchorA,anchorB,r);

             var joint:b2PulleyJoint=_world.CreateJoint(jointDef) as b2PulleyJoint;

         }

         override protected function stepBefore():void{ 

         }

     };

 }