   depth buffer and height mapping hijinx
  Hello Everyone;I want to write a small demo which shows a city and uses a height map for the terrain;In particular, I want the roads to be smooth, but the edges to be consistent more or less with the height map;  so I was thinking a cheap way to do this would be to render the height map first, and then clear the depth buffer before rendering the road.But I want other objects on in the scene (eg buildings) to be able to intersect with the height map as if the depth buffer were never cleared.Is there a simple way to do something like this, such as to copy the data from the depth buffer elsewhere before clearing it, and then restore it after the road has been drawn?Thanks,-Lunpa   
  Do'h, I could just disable the depth buffer and re-enable it again.Haha, never mind folks.   