Box2d性能问题

Question

我正在使用带有cocos2dx的Box2d。我在每个帧上创建一个动态的身体，并在创建150个动态身体后，游戏性能下降。这是我用来执行此操作的代码：

Settings()
{
    viewCenter.Set(0.0f, 20.0f);
    hz = 10.0f;
    velocityIterations = 8;
    positionIterations = 3;
    drawShapes = 1;
    drawJoints = 1;
    drawAABBs = 0;
    drawContactPoints = 0;
    drawContactNormals = 0;
    drawContactImpulse = 0;
    drawFrictionImpulse = 0;
    drawCOMs = 0;
    drawStats = 0;
    drawProfile = 0;
    enableWarmStarting = 1;
    enableContinuous = 1;
    enableSubStepping = 0;
    enableSleep = 1;
    pause = 0;
    singleStep = 0;
}

class Tumbler : public Test
{
public:

    enum
    {
        e_count = 800
    };

    Tumbler()
    {
        b2BodyDef bd;
        bd.allowSleep = true;
        bd.gravityScale = 9.8;
        ground = m_world->CreateBody(&bd);
        m_count = 0;
        m_count_obj = 0;


        bd2.type = b2_dynamicBody;
        bd2.allowSleep = true;
        bd2.gravityScale = 9.8f;
        bd2.position.Set(512,600);

        shape_.m_p.Set(0,0);
        shape_.m_radius = 4;
        body = NULL;
    }

    void Step(Settings* settings,cocos2d::Sprite* data)
    {
        Test::Step(settings,data);

        if (m_count_obj<=e_count && 0 == (m_count%15))
        {

            m_count_obj++;

            body = m_world->CreateBody(&bd2);
            body->SetUserData(data);
            body->SetBullet(false);
            body->SetLinearVelocity(b2Vec2(150,1500));
            body->CreateFixture(&shape_, 1.0f);

        }

        ++m_count;
    }

    static Test* Create()
    {
        return new Tumbler;
    }

    b2Body* ground = NULL;
    int32 m_count;
    int32 m_count_obj;
    b2EdgeShape shape;
    b2BodyDef bd2;
    b2CircleShape shape_;
    b2Body* body;
};

我需要创建大约3000个动态物体。我从cocos2dx示例中获得了此代码。