"David Fontaine" wrote:
> When using aa, does POV aa the alpha channel too so
> you can have a smooth transition to the background?

Yes, but unfortunately the *colour* isn't antialiased correctly.

When alpha is on, POV-Ray still use the background colour when it calculates
AA'ed pixels. It shouldn't. It's like it takes the background into account
twice - both in the colours and in the transparency. It should only do it in
the transparency.

Say you have a red sphere on a black background. The AA'ed pixels should
have the same red colour as the sphere but with some transparency. But
instead they are a darker red with some transparency because they are mixed
with the black background colour.

Result: When you use the alpha channel together with antialiasing, objects
will seem to have a very thin halo around them with the same colour as the
background colour you originally used.

But a much bigger problem is the way POV-Ray handles (semi-)transparent
objects. They are handled as though they were solid.

I'm not saying it's a bug. Maybe it's just an (in my opinion) unwanted
feature. But I would certainly appreciate it if somebody would fix it!

Rune
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