virtual void do_simulation_controller(IVP_Event_Sim *event,IVP_U_Vector<IVP_Core> *core_list)
	{
		int i;
		for( i = core_list->len()-1; i >=0; i--) 
		{
			IVP_Core *pCore = core_list->element_at(i);

			IVP_Real_Object *pivp = pCore->objects.element_at(0);
			CPhysicsObject *pPhys = static_cast<CPhysicsObject *>(pivp->client_data);
			
			float dragForce = -0.5 * pPhys->GetDragInDirection( pCore->speed ) * m_airDensity * event->delta_time;
			if ( dragForce < -1.0f )
				dragForce = -1.0f;
			if ( dragForce < 0 )
			{
				IVP_U_Float_Point dragVelocity;
				dragVelocity.set_multiple( &pCore->speed, dragForce );
				pCore->speed.add( &dragVelocity );
			}
			float angDragForce = -pPhys->GetAngularDragInDirection( pCore->rot_speed ) * m_airDensity * event->delta_time;
			if ( angDragForce < -1.0f )
				angDragForce = -1.0f;
			if ( angDragForce < 0 )
			{
				IVP_U_Float_Point angDragVelocity;
				angDragVelocity.set_multiple( &pCore->rot_speed, angDragForce );
				pCore->rot_speed.add( &angDragVelocity );
			}
		}
	}
void CPhysicsDragController::Tick(btScalar dt)
{
    for(int i = 0; i < m_ents.Size(); i++)
    {
        CPhysicsObject * object = (CPhysicsObject *)m_ents[i];

        Vector dragLinearFinal(0,0,0);
        AngularImpulse dragAngularFinal(0,0,0);

        Vector vel;
        AngularImpulse ang;
        object->GetVelocity(&vel, &ang);

        btVector3 bull_vel;

        ConvertPosToBull(vel, bull_vel);

        float dragForce = -0.5 * object->GetDragInDirection( &bull_vel ) * m_airDensity * dt;
        if ( dragForce < -1.0f )
        {
            dragForce = -1.0f;
        }
        if ( dragForce < 0 )
        {
            Vector dragLinearFinal = vel * dragForce;
        }
        btVector3 bull_angimpulse;
        ConvertAngularImpulseToBull(ang, bull_angimpulse);

        float angDragForce = -object->GetAngularDragInDirection(&bull_angimpulse) * m_airDensity * dt;
        if ( angDragForce < -1.0f )
        {
            angDragForce = -1.0f;
        }
        if( angDragForce < 0)
        {
            dragAngularFinal = ang * angDragForce;
        }
        object->AddVelocity(&dragLinearFinal, &dragAngularFinal);
    }
}