[Mesa-dev] [Bug 38869] Cannot create a valid pBuffer with height and/or width of zero

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=38869

--- Comment #4 from Jonathan Kirkham <jonathan.kirkham at arm.com> 2011-07-21 05:00:18 PDT ---
(In reply to comment #3)
> (In reply to comment #2)
> > (In reply to comment #0)
> > > Both the EGL and GLX specifications allow pbuffers to be created with a height
> > > and/or width of zero (and these are the default values).
> > 
> > Is there any language in the specs that specifically allow this?  If there is,
> > we should add a test case.
> 
> The spec says the default values for the width/height attribs are zero.  That's
> all I found after a quick skim.

(In reply to comment #1)
> "Both the EGL and GLX specifications allow pbuffers to be created with a height
> and/or width of zero (and these are the default values)."
> [...]
> "Other implementations throw a BAD_VALUE error in this case although this is
> not
> part of either specification."
> 
> I'm not clear on what you're saying.  According to the GLX spec, it looks like
> a size 0 x 0 pbuffer is legal.  But are you saying other implementations throw
> BadValue if you try that?
> 
> In Mesa, have you tried removing the width==0 || height==0 check?  If so, what
> happens when you create a 0x0 pbuffer?
> 
> Also, off-hand, I don't know of a way to directly generate an X error with Xlib
> calls.  Remember, the fake GLX layer we're talking about here has no internal
> hooks into X so we can't do everything that the real GLX library does.  I
> suppose we could set up an unrelated protocol request that purposely has bad
> arguments to generate the error.  If you need this, could you try to implement
> it?


I meant that other implementations that DO NOT support heights and widths of
zero (although they should be doing so) throw a BAD_VALUE error to indicate
that they cannot create the pbuffer.

Implementations that do support it (e.g. the Nvidia driver) return a valid
pbuffer handle that can be queryied etc.

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