Design issues (opengl, hdr, channels, pigment(?))

Tom Burdick tburdi1 at uic.edu
Fri Feb 2 05:56:21 CET 2007


Out of curiousity, when does opengl produce incorrect results?

If your using the built in image filtering then perhaps. If your using shaders 
or lookup tables (textures full of look up values) there shouldn't be a 
problem.

-Tom

On Thursday 01 February 2007 01:04:01 pm Cyrille Berger wrote:
> > > Which means, that we would need to have two plugins
> > > implementation, one for
> > > opengl and one for C++/mmx ?
> >
> > Why do you always need both implementations? Why not
> > always provide a general/slow C++ one and if there is
> > the need for a faster plugin, provide the openGL one
> > as well. Let krita dynamically decide which plugin is
> > best to use...
>
> That makes two implementations ;) (two implementation for each plugin that
> can be "openglised"). What I hoped we could do in the filters was:
>
> KisSomeOperation* op = colorSpace->constructSomeOperation();
>
> while(I can iterate)
> {
> 	op->transform(mypixelsfrommyiterator);
> }
>
> and have constructSomeOperation return the fastest implementation. On the
> other hand, as OpenGL seems to give inaccurate results, maybe having two
> plugins is better (like "fast but inaccurate blur" "slow but accurate
> blur", or add KisFilter::fastProcess(blabla); and use OpenGL only for
> previewing, while the correct transformation is applied on background)
>
> > > Yes it's plain asm files, so we don't want them :) I
> > > am still working on the
> > > library that would allow us to have the same
> > > implementation for mmx/sse and
> > > normal instruction.
> >
> > Sorry if this is neive but doesn't GCC already do
> > autovectorization and can optimize using mmx if the
> > correct compiler flags are used? (looks like pentium2
> > and higher)
> > Wouldn't it be better just to write the code to be as
> > clean as possible and check the resulting asm with all
> > of the optimization flags turned on?
>
> Because of :
>
> http://lists.kde.org/?l=kde-kimageshop&m=116603817419705&w=2
> and especially:
> http://lists.kde.org/?l=kde-kimageshop&m=116591635104447&w=2




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