> Because this 'solution' causes a lot of trouble (among others making HDR
> image output impossible without larger hacks).  And it does not solve
> the problem of non-linear tone mapping applied after the antialiasing
> step limiting the quality of the antialiasing results.

How does gamma correction after antialiasing limit the quality of the
antialiasing results?

If viewed on a monitor for which the gamma correction was correctly
performed, the gamma correction should exactly cancel out the monitor's
gamma effects, producing the original image as though non-linear tone
mapping never happened in the first place.

Gamma correction should always be done as the last thing in a renderer's
output. In fact, if the user plans to do anything more with the output
image, then they should turn off gamma correction, do whatever
postprocessing they want, and *then* apply gamma correction. Then, when the
image is displayed on a monitor, the gamma effects will cancel out the gamma
correction and present the viewer with the correct image.

> > So clip it at the maximum value that the output format supports? Which
> > happens still to be 1.0 at the vast majority of supported formats.
> >
>
> Could it be that you did not understand the fundamental difference
> between a HDR and a conventional image file format?  It does not make
> sense to speak of a maximum value in a HDR image file format, even if it
> has a theoretical maximum value.

HDR image output samples should be clipped, as Rune said, to the range which
the format supports. If HDR supports negative values, then the output should
be clipped to the range (-infinity, infinity) or in other words not clipped.
If it doesn't, then the output should be clipped to the range [0, infinity).

After this clipping, samples should be averaged together.

Finally, gamma correction should be applied as the last step as I mentioned
earlier.

 - Slime
 [ http://www.slimeland.com/ ]

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