I used alpha output with anti-aliasing but didn't get the desired result.
The anti-aliased pixels didn't have alpha values somewhere between 0 and 1.
Instead, they had values of either 0 or 1. So, it is impossible to render
anti-aliased objects for later compositing.

Roy

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Roy Schulz <roy### [at] gmxde> wrote:
: I used alpha output with anti-aliasing but didn't get the desired result.
: The anti-aliased pixels didn't have alpha values somewhere between 0 and 1.
: Instead, they had values of either 0 or 1. So, it is impossible to render
: anti-aliased objects for later compositing.

  Did you come to this conclusion from the preview window? If yes, then you
made too early conclusions. Although the preview window is unable to show
alpha-blended pixels, they are written ok to the image (as long as it's PNG).

  The next beta will have a pleasant surprise about this preview window
thing...

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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"Roy Schulz" wrote:
> I used alpha output with anti-aliasing but didn't get
> the desired result.

You can't count on what you see in the render window in POV-Ray. You have to
view the image in a program that supports the alpha channel, and even in
such a program you sometimes need to turn on the alpha channel yourself.

The next beta will correctly preview the alpha channel in the render window.

Rune
--
3D images and anims, include files, tutorials and more:
Rune's World:    http://rsj.mobilixnet.dk (updated June 26)
POV-Ray Users:   http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Webring: http://webring.povray.co.uk

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Warp wrote:
> 
> Roy Schulz <roy### [at] gmxde> wrote:
> : I used alpha output with anti-aliasing but didn't get the desired result.
> : The anti-aliased pixels didn't have alpha values somewhere between 0 and 1.
> : Instead, they had values of either 0 or 1. So, it is impossible to render
> : anti-aliased objects for later compositing.
> 
>   Did you come to this conclusion from the preview window? If yes, then you
> made too early conclusions. Although the preview window is unable to show
> alpha-blended pixels, they are written ok to the image (as long as it's PNG).
> 
	TGA also support alpha channel, I think.

-- 
Thierry http://la.buvette.org/exPOV/

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> Did you come to this conclusion from the preview window? If yes, then
> you made too early conclusions.

Mea culpa.

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On a related note, unless this has been changed since version 3.1, if you
output transparency to an image (like PNG), the following weirdness occurs:
a pixel whose ray passes through a 50% transparent object, and then hits the
background color will be colored 50% of the transparent object and 50% of
the background color. Then it is made 50% transparent.  What *should*
happen, however, is it should be 100% the color of the transparent object,
and 50% transparent. The background color shouldn't be a part of the pixel's
color, since the background itself is transparentness. This causes big
problems when you've got an object that's only 20% visible - the background
color dominates the pixel, but it should be dominated by the transparent
object. Again, the background color should be invisible, and the percent of
color that comes from the background should only serve to be the percent of
transparency of that pixel.

I dunno if this really qualifies as a "bug" that should be fixed.

--
- Slime
[ http://www.teja.nu/slime/ ]
[ http://www.teja.nu/slime/images/ ]
"Roy Schulz" <roy### [at] gmxde> wrote in message
news:3bb6df38@news.povray.org...
> I used alpha output with anti-aliasing but didn't get the desired result.
> The anti-aliased pixels didn't have alpha values somewhere between 0 and
1.
> Instead, they had values of either 0 or 1. So, it is impossible to render
> anti-aliased objects for later compositing.
>
> Roy
>
>
>

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On Mon, 1 Oct 2001 12:13:49 -0400, Slime wrote:
>I dunno if this really qualifies as a "bug" that should be fixed.

Probably not.  But because it was fixed before beta 1 came out, rather than
for any other reason.

--
#macro R(L P)sphere{L __}cylinder{L P __}#end#macro P(_1)union{R(z+_ z)R(-z _-z)
R(_-z*3_+z)torus{1__ clipped_by{plane{_ 0}}}translate z+_1}#end#macro S(_)9-(_1-
_)*(_1-_)#end#macro Z(_1 _ __)union{P(_)P(-_)R(y-z-1_)translate.1*_1-y*8pigment{
rgb<S(7)S(5)S(3)>}}#if(_1)Z(_1-__,_,__)#end#end Z(10x*-2,.2)camera{rotate x*90}

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