   deferred shading (skies)
  The algorithm:1.) Do all deferred lighting.2.) Draw the sky last.I was reading the stalker paper and it suggested that because of this, the top half of the screen pretty much wont need to be calculated for lighting. But the only way of doing lighting for a directional light outdoors, would be to draw a fullscreen quad and still light the pixels where the sky will exist in the end.So is the only way to accomplish this through stenciling?   