Re: AW: [Openexr-devel] Missing include - and other questions...

[Drew Hess]

Hi Matthias,

If you have a programmable GPU available with support for 16-bit FP
pixels, you can do a neat trick with a Cg shader and a 16-bit lookup
table.  Assuming you can bake your tonemap into the table and you have the
right hardware, this is pretty fast.

I've attached the Cg shader that does this.


-dwh-



On Mon, 26 Jan 2004, Matthias Biedermann wrote:

> Hi folks,
> 
> 
> thanks for your quick answers!
> 
> Well, I've already investigated into that tone-mapping stuff and have
> found Reinhard's technique implemented in your toolset "exrtools",
> Billy. 
> However, the tonemapping needed for my work (which will finish in the
> midst of June...) is just for displaying the HDR as textures, so
> "business as usual". The "problem" is that tonemapping is not the main
> focus of my thesis and thus doesn't have to be very sophisticated but
> rapid. As I'm dynamically rendering HDR-cubemaps in moving/interactive
> scenes lit by a static (but rotateable/exchangeable) HDR-lightprobe
> there is not much time to use clever multipass operators and such - the
> GPU will have enough fun with the spherical harmonics anyway...;->
> 
> So if you can recommend or tell about experiences with some fast global
> tonemapping operators like some sort of log-mapping
> (Weber-Fechner's-law, global step of Reinhard's) or (N)URQV, I'd be
> happy about any information!
> 
> 
> Bye,
> Matthias
> 
> 
> 
> 
> > -----Ursprüngliche Nachricht-----
> > Von: Billy Biggs [mailto:address@hidden 
> > Gesendet: Montag, 26. Januar 2004 21:46
> > An: Matthias Biedermann
> > Cc: address@hidden
> > Betreff: Re: [Openexr-devel] Missing include - and other questions...
> > 
> > 
> > Florian Kainz (address@hidden):
> > 
> > > > btw: I'm very delighted to have found such a flexible and 
> > extensible 
> > > > open-source tool for handling HDR-images as I need them 
> > (along with 
> > > > other stuff) in my diploma thesis. Is there already more 
> > information 
> > > > available for using OpenEXR with dynamic rendering of cubemaps as 
> > > > XXXXX has asked ...? Or some general "paper"-stuff about 
> > OpenEXR and 
> > > > its concepts (like tonemapping etc.) to use for citations?
> > > 
> > > [...]
> > >
> > > No tone-mapping techniques I know of depend on a particular 
> > image file 
> > > format.  The only requirement is, of course, that the input 
> > files must 
> > > be able to represent the image's full dynamic range.  For various 
> > > papers about tone mapping, check the SIGGRAPH proceedings 
> > from 1998 to 
> > > 2003.
> > 
> >   Techniques don't depend on a file format, but implementations
> > sometimes do. ;-)   I implement some tone mapping algorithms in
> > exrtools, and will post improved versions soon.
> > 
>   http://scanline.ca/exrtools/
> 
>   -Billy
> 
> 
> 
> _______________________________________________
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> http://mail.nongnu.org/mailman/listinfo/openexr-devel
> 
> 
>

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