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View Full Version : wglGetProcdress("wglCopyImageSubDataNV") fails ?!



henniman
10-13-2009, 03:49 AM
Hi all,

i have NV Driver 191.07 istalled,
( XP 32, 1x NV8800GTX, 1x6200 TurboCache )

and
wglGetProcdress("wglCopyImageSubDataNV") fails
wglGetProcdress("glCopyImageSubDataNV") works

the spec says

-----
Name NV_copy_image

Name Strings

GL_NV_copy_image
WGL_NV_copy_image
GLX_NV_copy_image

[...]

Status Shipping (July 2009, Release 190)
---


am i doing something wrong?

Best,
Hendrik

aqnuep
10-13-2009, 07:54 AM
I suppose only GL_NV_copy_image extension is exposed by the implementation, but not WGL_NV_copy_image. Usually in case of those extensions which have all the three forms (GL/WGL/GLX) the function is exposed only in form of glFunctionName.

I don't have an NVIDIA card but I suppose this is the case, so skip the first line.

henniman
10-13-2009, 10:30 AM
Yes, i think this is the case, too.
I am interested
in the wglCopyImageSubDataNV function call since it
should be able to copy data across contexts.

But just to be sure: i do not have to make
some more initialization to get wgl procedure adresses?
If the call for the gl function adress succeeds, there is
no other possible cause than the wgl function is not
implemented?

Thanks
Hendrik

aqnuep
10-14-2009, 12:37 AM
You don't need a WGL version of the function to copy data across contexts. Textures can be always shared between contexts, so the textures visible in the first context can be used also in the other one.

So you can simply use the normal version of the function.
Just be careful to synchronize the two contexts (this is needed anyway).

skynet
10-14-2009, 12:49 AM
...but you cannot share textures between contexts on separate GPUs. I think, wglCopyImageSubDataNV works in tandem with NV_gpu_affinity, which is only available on Quadro cards. So it might be possible that WGL_NV_copy_image is Quadro-only, too.

aqnuep
10-14-2009, 01:18 AM
I don't think that there is any word about in WGL_NV_copy_image is multi-GPU related stuff. Also it's for sure not Quadro-only. I have to read more about NV_gpu_affinity but I suppose that there should be some way to share some resources between separate GPU contexts. Otherwise the whole multi-GPU stuff would loose most of it's sense (at least in my vision).

henniman
10-14-2009, 08:52 AM
i got some information that the WGL_NV_copy_image extension is only supported on quadro cards.

anyway i never got any decent doc about this
multi/single/performance/compatibility modes
in nvidia drivers. can anyone help here?