Re: [Openexr-devel] OpenEXR on the desktop!

[Ken McGaugh]

Drew Hess wrote:
> One thing you can do is load an image, convert it to its 8-bit
> representation ("baking in" the exposure, filmlook, gamma, etc.), and
> then throw out the OpenEXR image, leaving only the 8-bit version.
> Rinse and repeat.
>
> The problem with that method is that whenever you want to change one
> of those baked-in parameters, you have to reload the entire sequence
> and do it again.

We do something similar.  We bake in a simple tone mapping operation which
is basically a gamma and a softclip (knee function).  But what the user sees
actually goes through an 8-bit lookup table executed in a fragment shader
(and optionally a 3D lookup table as well).  The exposure control and desired
look parameters control how this 8-bit lookup table is generated.  You'd be
surprised how far you can re-expose and/or change the other parameters before
you start to see the quantizing.

--Ken