clipka <ano### [at] anonymousorg> wrote:
> Am 08.05.2010 07:43, schrieb Warp:

> >    I don't know why anyone would want to use anything else than what 3.6 did,
> > but even if more options are made available, the 3.6 way should definitely
> > be the default, as it's the most useful and it's what people expect.

> One could argue that e.g. sky spheres should show up in the background, 
> to allow for rendering opaque clouds against an otherwise transparent 
> background.

  You mean that, with respect to alpha transparency, the sky_sphere would
work the same as if it was an actual sphere primitive with that texture
(naturally without lighting affecting it)?

  I agree that it sounds sensible and could be useful.

  (Nitpicking, but I disagree on the clouds example, though. sky_sphere is
the wrong but unfortunately too much used place to put clouds. Clouds do not
work that way in real life. Clouds work much better on a *plane* which is
parallel to the ground. :) )

> I've also found that 3.6 is /not/ doing it right either (at least with 
> regard to PNG), as it premultiplies alpha. Maybe 3.5 had that right, and 
> people complained about /that/ change?

  I don't really understand the difference. It has never come up as any kind
of problem when I have used POV-Ray 3.6 to render some alpha-channeled images.

  (Is the perceived problem that pre-multiplying means that some color
accuracy can be lost in the process?)

-- 
                                                          - Warp

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