[Bf-committers] Re: image editor / draw alpha

[Branan Riley]

Fixed the patch upload, I think. Sorry about that.

On 6/14/06, Ton Roosendaal <ton at blender.org> wrote:
> Hi,
>
> Using defines for endianness is a bit cumbersome. In Blender code we
> use this:
>
> ./blenkernel/intern/blender.c:207:      G.order= 1; /* is short */
> ./blenkernel/intern/blender.c:208:      G.order=
> (((char*)&G.order)[0])?L_ENDIAN:B_ENDIAN
>
> Gives guaranteed results. :)
>
> I cannot find a reason why makefiles or scons should should set such
> defines... apart from some of the non-Blender libraries.
>
> -Ton-
>
>
> On 14 Jun, 2006, at 3:16, Ed Halley wrote:
>
> >
> > On Jun 13, 2006, at 7:47 PM, Branan Riley wrote:
> >> I'm running Gentoo Linux x86-64 on a Pentium 4, so endianness is
> >> probably the issue. I don't think testing for the Mac OS define would
> >> work, since there are also Intel-based macs. Does anyoen know the
> >> right define to check for to distinguish endianness?
> >
> > The current patch* for Mac Intel endianness looks for each of these:
> >
> >    #if ... || defined(__APPLE__)
> >
> > and turns them into
> >
> >    #if ... || (defined(__APPLE__) && !defined(__LITTLE_ENDIAN__))
> >
> > Similar adjustments are made in a couple makefiles.
> >
> > I am all for defining a better symbol to drive these checks, but this
> > seems to work for the few CLEARLY UNDERSTOOD endian issues.
> >
> > It is important for any code that deals with byte packing to be CLEAR
> > about its intentions.  This "it works because alpha is the low byte of
> > an int" stuff can't be sufficient.  More rigorous testing is needed,
> > and developers can't get complacent about assuming that all machines
> > work the same way that their favorite machine works.
> >
> > * (the current patch being what was passed around unofficially as
> >    'dougcorrs.diff' but never got posted on the patch server)
> >
> > --
> > [ e d @ h a l l e y . c c ]
> >
> >
> >
> >
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> >
> >
> >
> ------------------------------------------------------------------------
> --
> Ton Roosendaal  Blender Foundation ton at blender.org
> http://www.blender.org
>
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