On Mon, 31 Jul 2000 17:12:33 +1200, "Edmund Horner"
<ejr### [at] paradisenetnz> wrote:

>Hello all.
>
>Lately I've been planning to raytrace a whole lot of graphics for a game I'm
>making...  Antialiased pictures would be nicer, of course, but that leaves
>the issue of which background colour to use for the rendering.

Use the alpha channel output (+UA with png or tga output). The alpha
channel, as POV interprets it, is an additional channel in the image
which represents the amount of "presense" in a pixel. The background
(or sky_sphere) get a 0 and a direct hit in an object gets 255.
Antialiasing does its job here, too, so anything in between 0 and 255
will happen on the edges of objects, which you find problematic.

Now, with the alpha channel output, you can open the graphic in a
paint program and defringe the edges so that the background color is
removed. In PhotoShop, you have to set the background to whatever it
is in your scene, open the file, load the alpha channel as a
selection, copy then paste to a new file, and then defringe.

If you don't have PhotoShop available, I am certain the GIMP or
PaintShop Pro have such abilities. If they do not, you can come up
with the same result using MegaPOV post-processing, but it will be
more tedious.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] usanet
TAG      e-mail : pet### [at] tagpovrayorg

Post a reply to this message