Croquet ARB_imaging

Bert Freudenberg bert at isg.cs.uni-magdeburg.de
Sun Dec 22 00:32:15 UTC 2002


Am Sonntag, 22.12.02 um 00:51 Uhr schrieb Joshua 'Schwa' Gargus:
>
> About your hack... when you say "if your renderer changes", you mean
> like if I have a dual-head setup with two different graphics cards,
> and I drag the Squeak window from one to the other?  Wouldn't this
> be a problem even if the function could be found directly in
> opengl32.dll?  Oh, I think I see... the function in opengl32.dll
> probably redirects the call to whichever driver is currently active.
> But when you use wglGetProcAddress, that indirection no longer
> occurs, so if the renderer changes, you're sunk.  Does that sound
> right?

Not quite. The function address returned by getProcAddress is OpenGL 
context specific. So when you have more than one context, or you 
destroy and create one, the absolutely correct way is to get a new 
function address. In practice, the address is only driver specific  and 
can be safely shared across all contexts on a device. It may differ 
between physical screens, however.

-- Bert




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