btRigidBody* Okno::addBolw(float x,float y,float z,float mass)
{
    btTransform t;  //position and rotation
    t.setIdentity();
    t.setOrigin(btVector3(x,y,z));  //put it to x,y,z coordinates
    btCylinderShape * cylinder1 = new btCylinderShape(btVector3(1,1.7,1));

    btCylinderShape * cylinder2 = new btCylinderShape(btVector3(0.5, 1, 0.5));
    btCompoundShape * bolw = new btCompoundShape();
    bolw->addChildShape(t,cylinder1);
    t.setIdentity();
    t.setOrigin(btVector3(x,y+2.7,z));
    bolw->addChildShape(t, cylinder2);
    btVector3 inertia(0,0,0);
    btScalar masses[2] = { mass,mass/2};
    bolw->calculatePrincipalAxisTransform(masses,t,inertia);
    t.setIdentity();

    btMotionState* motion=new btDefaultMotionState(t);  //set the position (and motion)
    btRigidBody::btRigidBodyConstructionInfo info(mass*2,motion,bolw,inertia);  //create the constructioninfo, you can create multiple bodies with the same info
    btRigidBody* body=new btRigidBody(info);    //let's create the body itself
    body->setFriction(1);
    body->setRestitution(0);
    world->addRigidBody(body);  //and let the world know about it
    bodies.push_back(body); //to be easier to clean, I store them a vector
    return body;

}