Well, as you've noticed Paul, it makes no sense semantically to use an
entry point queried with one context while another is bound; yet that's
exactly what people are pushing for. However to answer your specific
question; presumably the implementation would solve this by installing a
stub entry point in the dispatch state for contexts which do not support
this extension. The stub would simply set an error and return. As Steve
points out, it is an error to call the entry point when the extension is
not supported, and this extension should never be considered a substitute
from querying the GL_EXTENSIONS string.
At 09:00 AM 10/14/99 -0400, Paul Miller wrote:
>> I've only heard one implementor opine that a driver would be more
>> difficult to implement due to GetProcAddress returning context
>> independent pointers. As another implementor, I don't agree.
>
>A lot of discussion here has been on the side of the driver-writer. As
>an application developer interested in multi-head OpenGL applications,
>I'm wondering what would happen in a (contrived) scenario like this:
>
>I have two graphics accelerators installed. The "main" one is a typical
>AGP 2D/3D card like the TNT2 or a Diamond FireGL 1. It can do
>1280x1024x32 with 32-bit Z and 8-bit stencil. My second head is attached
>to a PCI-based board that can do 1600x1200x64 (16-bits per component)
>with a 21-bit log Z and 8-bit stencil, plus it can do multitexture and
>some other extensions.
>
>My application is smart enough to put the typical controls on the
>"typical" card, and the fancy super-high-res deep-pixel image processing
>windows on the "fancy" card. Naturally I'm interested in whatever
>extensions are present in the fancy card such as MultiTexture and the
>future SeparateAlphaBlendMode extension.
>
>Since I have these different windows, I would expect to be able to get
>different features/extensions from the different contexts. What would
>happen when I query the extensions with context-independent function
>pointers? Assuming I get a pointer, what happens when I call it?
>
>Sorry for the long-winded example. :-)
>
>--
>Paul T. Miller | [EMAIL PROTECTED]
>Principal Engineer | Softimage Graphics and Effects Software Group
>Avid Technology, Inc. | Opinions expressed here are my own.
