ogre visibleflag

/** Sets a mask which is bitwise 'and'ed with objects own visibility masks
            to determine if the object is visible.
        @remarks
            Note that this is combined with any per-viewport visibility mask
            through an 'and' operation. @see Viewport::setVisibilityMask
*/
virtual void setVisibilityMask(uint32 vmask) { mVisibilityMask = vmask; }

=========================================
/** Sets the visiblity flags for this object.
        @remarks
            As well as a simple true/false value for visibility 
(as seen in setVisible), 
            you can also set visiblity flags which when 'and'ed

with the SceneManager's
            visibility mask can also make an object invisible.
*/
virtual void setVisibilityFlags(uint32 flags) { mVisibilityFlags = flags; }