public WeldJointDef()
 {
     type = JointType.WELD;
     localAnchorA = new Vec2();
     localAnchorB = new Vec2();
     referenceAngle = 0.0f;
 }

 /// <summary>
 /// Initialize the bodies, anchors, axis, and reference angle using the world anchor and world axis.
 /// </summary>
 public virtual void initialize(Body bA, Body bB, Vec2 anchor)
 {
     bodyA = bA;
     bodyB = bB;
     bA.getLocalPointToOut(anchor, localAnchorA);
     bB.getLocalPointToOut(anchor, localAnchorB);
 }

 public ContactPositionConstraint()
 {
     for (int i = 0; i < LocalPoints.Length; i++)
     {
         LocalPoints[i] = new Vec2();
     }
 }

 /// <summary>
 /// Initialize the bodies, anchors, axis, and reference angle using the world anchor and world axis.
 /// </summary>
 public void Initialize(Body bA, Body bB, Vec2 anchor)
 {
     BodyA = bA;
     BodyB = bB;
     bA.GetLocalPointToOut(anchor, LocalAnchorA);
     bB.GetLocalPointToOut(anchor, LocalAnchorB);
 }

 public WeldJointDef()
 {
     Type = JointType.Weld;
     LocalAnchorA = new Vec2();
     LocalAnchorB = new Vec2();
     ReferenceAngle = 0.0f;
 }

 public FrictionJointDef()
 {
     Type = JointType.Friction;
     LocalAnchorA = new Vec2();
     LocalAnchorB = new Vec2();
     MaxForce = 0f;
     MaxTorque = 0f;
 }

 public FrictionJointDef()
 {
     type = JointType.FRICTION;
     localAnchorA = new Vec2();
     localAnchorB = new Vec2();
     maxForce = 0f;
     maxTorque = 0f;
 }

 protected internal Vec2[] GetInitializedArray(int argLength)
 {
     var ray = new Vec2[argLength];
     for (int i = 0; i < ray.Length; i++)
     {
         ray[i] = new Vec2();
     }
     return ray;
 }

 public WorldManifold()
 {
     normal = new Vec2();
     points = new Vec2[Settings.maxManifoldPoints];
     for (int i = 0; i < Settings.maxManifoldPoints; i++)
     {
         points[i] = new Vec2();
     }
 }

 public WorldManifold()
 {
     Normal = new Vec2();
     Points = new Vec2[Settings.MAX_MANIFOLD_POINTS];
     for (int i = 0; i < Settings.MAX_MANIFOLD_POINTS; i++)
     {
         Points[i] = new Vec2();
     }
 }

 /// <summary> creates a manifold with 0 points, with it's points array full of instantiated ManifoldPoints.</summary>
 public Manifold()
 {
     points = new ManifoldPoint[Settings.maxManifoldPoints];
     for (int i = 0; i < Settings.maxManifoldPoints; i++)
     {
         points[i] = new ManifoldPoint();
     }
     localNormal = new Vec2();
     localPoint = new Vec2();
     pointCount = 0;
 }

 public PulleyJointDef()
 {
     Type = JointType.Pulley;
     GroundAnchorA = new Vec2(-1.0f, 1.0f);
     GroundAnchorB = new Vec2(1.0f, 1.0f);
     LocalAnchorA = new Vec2(-1.0f, 0.0f);
     LocalAnchorB = new Vec2(1.0f, 0.0f);
     LengthA = 0.0f;
     LengthB = 0.0f;
     Ratio = 1.0f;
     CollideConnected = true;
 }

        /// <param name="argWorldPool"></param>
        /// <param name="def"></param>
        public FrictionJoint(IWorldPool argWorldPool, FrictionJointDef def)
            : base(argWorldPool, def)
        {
            m_localAnchorA = new Vec2(def.localAnchorA);
            m_localAnchorB = new Vec2(def.localAnchorB);

            m_linearImpulse = new Vec2();
            m_angularImpulse = 0.0f;

            m_maxForce = def.maxForce;
            m_maxTorque = def.maxTorque;
        }

 public PulleyJointDef()
 {
     type = JointType.PULLEY;
     groundAnchorA = new Vec2(-1.0f, 1.0f);
     groundAnchorB = new Vec2(1.0f, 1.0f);
     localAnchorA = new Vec2(-1.0f, 0.0f);
     localAnchorB = new Vec2(1.0f, 0.0f);
     lengthA = 0.0f;
     lengthB = 0.0f;
     ratio = 1.0f;
     collideConnected = true;
 }

 public PolygonShape()
     : base(ShapeType.Polygon)
 {
     VertexCount = 0;
     Vertices = new Vec2[Settings.MAX_POLYGON_VERTICES];
     for (int i = 0; i < Vertices.Length; i++)
     {
         Vertices[i] = new Vec2();
     }
     Normals = new Vec2[Settings.MAX_POLYGON_VERTICES];
     for (int i = 0; i < Normals.Length; i++)
     {
         Normals[i] = new Vec2();
     }
     Radius = Settings.POLYGON_RADIUS;
     Centroid.SetZero();
 }

        static void Main(string[] args)
        {
            // Static Body
            Vec2 gravity = new Vec2(0, -10);
            bool doSleep = true;
            World world = new World(gravity);
            world.SleepingAllowed = doSleep;
            BodyDef groundBodyDef = new BodyDef();
            groundBodyDef.position.set_Renamed(0, -10);
            Body groundBody = world.createBody(groundBodyDef);
            PolygonShape groundBox = new PolygonShape();
            groundBox.setAsBox(50, 10);
            groundBody.createFixture(groundBox, 0);

            // Dynamic Body
            BodyDef bodyDef = new BodyDef();
            bodyDef.type = BodyType.DYNAMIC;
            bodyDef.position.set_Renamed(0, 4);
            Body body = world.createBody(bodyDef);
            PolygonShape dynamicBox = new PolygonShape();
            dynamicBox.setAsBox(1, 1);
            FixtureDef fixtureDef = new FixtureDef();
            fixtureDef.shape = dynamicBox;
            fixtureDef.density = 1;
            fixtureDef.friction = 0.3f;
            body.createFixture(fixtureDef);

            // Setup world
            float timeStep = 1.0f / 60.0f;
            int velocityIterations = 6;
            int positionIterations = 2;

            // Run loop
            for (int i = 0; i < 60; ++i)
            {
                world.step(timeStep, velocityIterations, positionIterations);
                Vec2 position = body.Position;
                float angle = body.Angle;
                Console.WriteLine("{0:0.00} {1:0.00} {2:0.00}", position.x, position.y, angle);
            }
        }

 public override void getAnchorB(Vec2 argOut)
 {
     m_bodyB.getWorldPointToOut(m_localAnchorB, argOut);
 }

        public PrismaticJoint(IWorldPool argWorld, PrismaticJointDef def)
            : base(argWorld, def)
        {
            m_localAnchorA = new Vec2(def.localAnchorA);
            m_localAnchorB = new Vec2(def.localAnchorB);
            m_localXAxisA = new Vec2(def.localAxisA);
            m_localXAxisA.normalize();
            m_localYAxisA = new Vec2();
            Vec2.crossToOutUnsafe(1f, m_localXAxisA, m_localYAxisA);
            m_referenceAngle = def.referenceAngle;

            m_impulse = new Vec3();
            m_motorMass = 0.0f;
            m_motorImpulse = 0.0f;

            m_lowerTranslation = def.lowerTranslation;
            m_upperTranslation = def.upperTranslation;
            m_maxMotorForce = def.maxMotorForce;
            m_motorSpeed = def.motorSpeed;
            m_enableLimit = def.enableLimit;
            m_enableMotor = def.enableMotor;
            m_limitState = LimitState.INACTIVE;

            m_K = new Mat33();
            m_axis = new Vec2();
            m_perp = new Vec2();
        }

 public override void getReactionForce(float inv_dt, Vec2 argOut)
 {
     argOut.set_Renamed(m_uB).mulLocal(m_impulse).mulLocal(inv_dt);
 }

 /// <summary>
 /// Ray-cast the world for all fixtures in the path of the ray. Your callback controls whether you
 /// get the closest point, any point, or n-points. The ray-cast ignores shapes that contain the
 /// starting point.
 /// </summary>
 /// <param name="callback">a user implemented callback class.</param>
 /// <param name="point1">the ray starting point</param>
 /// <param name="point2">the ray ending point</param>
 public virtual void raycast(RayCastCallback callback, Vec2 point1, Vec2 point2)
 {
     wrcwrapper.broadPhase = m_contactManager.m_broadPhase;
     wrcwrapper.callback = callback;
     input.maxFraction = 1.0f;
     input.p1.set_Renamed(point1);
     input.p2.set_Renamed(point2);
     m_contactManager.m_broadPhase.raycast(wrcwrapper, input);
 }