anchor.diff:  ;;                   ResHandle materialRes, int layer);
   (defh3fun ("showOverlay" show-overlay) void
     "Shows an overlay on the screen.
  -		
  +                
   This function displays an overlay with a specified material at a specified position on the screen.
   An overlay is a 2D image that can be used to render 2D GUI elements. The coordinate system
   used has its origin (0, 0) at the top-left corner of the screen and its maximum (1, 1) at
  
positive.code:                         how many units per second particle is moving; valid for get-/setResourceParamf
     :move-vel-max      - Maximum value for selecting random initial value of velocity defining
                          how many units per second particle is moving; valid for get-/setResourceParamf
     :move-vel-end-rate - Percentage of the initial translation velocity value when particle is dying;
                          valid for get-/setResourceParamf
     :rot-vel-min       - Minimum value for selecting random initial value of velocity defining
                          how many degrees per second particle is rotating; valid for get-/setResourceParamf
     :rot-vel-max       - Maximum value for selecting random initial value of velocity defining
  
negative.code:    :camera          - Camera giving view on scene
     :emitter         - Particle system emitter
     :terrain         - Terrain node
     :listener        - Listener node
     :sound           - Sound node
  "
    (:undefined 0)
    :group
  