"clipka" <nomail@nomail> wrote:
> "JeffBTX" <nomail@nomail> wrote:
> > Antialias_Clipped is not covered in the documentation (revision.txt says that
> > the documentation WAS changed, but searching the CHM file I cannot find +ac,
> > +AC, or Antialias_Clipped). Would appreciate an explanation, I can't even guess
> > what "CLIPPING" is in relation to antialiasing...
>
> FYI: This refers to the clipping of overly-bright colors to the displayable
> range (0.0 to 1.0 in POV-Ray terms, or 0..255 in 8-bit RGB terms).
>
> With anti-aliasing active, "prehistoric" versions of POV-Ray clipped such colors
> on a *per-ray* basis, instead of the resulting pixel value. This seems to have
> been changed in the course of introduction of proper gamma handling, so that
> POV-Ray 3.6.1 clipped the colors on a per-pixel basis; note that this has the
> same effect as generating HDR output, and converting the image to 8-bit in a
> post-processing step.
>
> However, in some situations - especially with extremely-overly-bright objects in
> the scene - this approach may seem to give inferior results, which may be the
> reason why it was re-introduced later (as an option) in 2007 (but never
> released before; interestingly, it has also never been re-introduced to 3.7).
>
> However, I think it was an oversight to include the 2007 change into 3.6.2
> without at least changing the default to "off", as this has been the standard
> for years now.
>
> As already mentioned, POV-Ray 3.7 also invariably uses per-pixel clipping
> (unless HDR output is used of course, in which no clipping is performed at
> all).

.... then it sounds like something "not- to- worry- about", for someone
transitioning from 3.6.1 to 3.6.2 (I think...)

.... thanks for your reply Clipka.

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