What does the PFD_MAIN_PLANE mean?

OpenGL OpenGL: Basic Coding
1

Hi!
I’m using Delphi 5.0 and OpenGL with it.
Can you tell me what does the “iLayerType” field of the PixelFormatDescriptor stands for? One of the valid choose of “iLayerType” is “PFD_MAIN_PLANE”, can you tell me what does it mean?
Thank you!

2

MSDN Quote :

iLayerType
Ignored. Earlier implementations of OpenGL used this member, but it is no longer used.

EDIT : ok, looks like MS changed its docs… The online MSDN says that iLayerType can be MAIN, OVERLAY or UNDERLAY. Doesn’t say it is ignored anymore… Anyway… MAIN_PLANE means that the OpenGL window will share the usual graphics layer (== Windows frame buffer). Overlays and underlays can be used for special compositing effects. Never seen any sample code using them though.

[This message has been edited by kehziah (edited 07-10-2003).]

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Thank you!