   DirectDraw Overlay
  Hi,I am writing a tool which overlays real-time system information onto the screen while the user is playing a game, using an overlay surface. I currently have it display a black box in the YUV2 pixel format. I am wondering if it is possible to set certain colours to transparent, so that the game is visible underneath certain parts of the overlay. I believe that this should be done via colour keys, but I heard that Nvidia cards do not support it. Is this true, or is it possible to this with Nvidia cards? If so, are there any examples?Thanks,Matt   