Andy Walker (awalker++at++multigen.com)
Wed, 19 Nov 1997 13:49:00 -0800
http://www.multigen.com/support/TechNotes/sgi_support/sgi_support.htm
Andrew R. Walker Email: awalker++at++multigen.com
Usability and Design Work: (408) 556-2627
MultiGen Inc. Fax: (408) 261-4101
San Jose, CA. 95125
> -----Original Message-----
> From: Steve Baker [SMTP:sbaker++at++link.com]
> Sent: Wednesday, November 19, 1997 11:14 AM
> To: Garrett Williams
> Cc: sgi; MultiGen
> Subject: Re: tree border
>
> On Wed, 19 Nov 1997, Garrett Williams wrote:
>
> > Just wondering if any one knew how to clean up the edges of tree
> > models..
> >
> > I have a T tree model with a rgba image applied. BUT at a distance
> away
> > the tree gets a white border around it making it look real bad...
>
> When you paint a texture map, you have to appreciate that
> MIP mapping will gradually blend together more and more of
> the texels as the range and/or slope increases.
>
> In the case of an '.inta' or '.rgba' map, this will cause two
> bad things to happen:
>
> 1) The pixels that you though would be clipped out by the
> transparency will gradually become semi-transparent, and
> hence you will start to see parts of the image that you
> thought you had thrown away.
>
> 2) The areas outside of the opaque region will gradually
> get mixed into the visible part.
>
> The simplest solution is to paint the areas of the RGB map
> that are transparent with colours similar to those found
> in the tree itself.
>
> In addition, I build my own MIP-maps (rather than letting
> Performer/OpenGL do it for me) so that I can control the
> contents of the lower level of detail maps. This is essential
> IMHO if you are going to make significant use of translucent
> textures.
>
> Steve Baker 817-619-8776 (Vox/Vox-Mail)
> Hughes Training Inc. 817-619-4028 (Fax)
> 2200 Arlington Downs Road SBaker++at++link.com (eMail)
> Arlington, Texas. TX 76005-6171 SJBaker1++at++airmail.net (Personal eMail)
> http://www.hti.com http://web2.airmail.net/sjbaker1
> (personal)
>
> ** Beware of Geeks bearing GIF's. **
>
>
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