[Mesa-dev] COMPSIZE function in OpenGL XML registry

[Shervin Sharifi]

Thank you.
I think there should be a way to calculate the size of the memory location
pointed by that pointer.
For cases where there is no shared memory between the client and the
server, the memory contents should be copied back and forth, which means
the size of the pointer should be known (unless I'm missing something).

Thanks,
  Shervin



On Wed, Jun 10, 2015 at 11:44 AM, Matt Turner <mattst88 at gmail.com> wrote:

> On Wed, Jun 10, 2015 at 11:25 AM, Shervin Sharifi <shervin0 at gmail.com>
> wrote:
> > Hi,
> >
> >  This may not be the right forum to ask this, but I didn't know of a
> better
> > forum, so I thought I can ask here.
> >
> >  I'm new to OpenGL. I am looking at XML registry for OpenGL and there are
> > some parameters with attributes containing a function COMPSIZE (I've
> pasted
> > an example below).
> >  I tried to find information on what the COMPSIZE function is, where/how
> it
> > is used, etc, but couldn't find documentation or credible information on
> the
> > Internet.
> >  Any information or pointer to that would be really helpful.
> >
> >  Thanks,
> >     Shervin
> >
> >
> >
> > This example is from gl.xml in the OpenGL registry:
> >
> >         <command>
> >             <proto>void <name>glBinormalPointerEXT</name></proto>
> >             <param group="BinormalPointerTypeEXT"><ptype>GLenum</ptype>
> > <name>type</name></param>
> >             <param><ptype>GLsizei</ptype> <name>stride</name></param>
> >             <param len="COMPSIZE(type,stride)">const void
> > *<name>pointer</name></param>
> >         </command>
>
> I'm just speculating, but I don't think there's really a definition of
> COMPSIZE or anything. I think it's just a way of saying that, for
> instance, the size of the memory pointed by the "pointer" parameter to
> glBinormalPointerEXT is a function of the "type" and "stride"
> parameters.
>
> Other functions, like glBitmap have similar things:
>
>             <param len="COMPSIZE(width,height)">const
> <ptype>GLubyte</ptype> *<name>bitmap</name></param>
>
> That is, the size of the block of memory pointed to by "bitmap" is
> described by the "width" and "height" parameters.
>
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