Angus Dorbie (dorbie++at++bitch.reading.sgi.com)
Wed, 14 Aug 1996 22:31:00 +0100
(so that's what he meant, maybe I should learn to read)
Aha! NOW I get it, I didn't realise a stencil write was being made even on
a z fail (didn't know it was possible). Cheap perfect quality decals, great!
I think I might venture to use these now, unless I have big ones.
I must have been wrong about the Paradigm APEX demo looks like it's treating
both tail fins as the same base layer. A danger of pfdCombineLayers perhaps?
Thanks (everyone),
Angus.
On Aug 14, 11:01am, Sharon Clay wrote:
> Subject: Re: Flimmering
> +>---- On Aug 14, 6:01pm, Angus Dorbie wrote:
> > Subject: Re: Flimmering
> ->
> ->In the scenario below the decal2 will show through base1 & decal1 if you
> ->draw base1 & decal1 first. This is what I meant by "occlusion between
> ->decal surfaces", I didn't mean decals on the same base.
>
> No - Base2 will write 0 to the stencil bit everywhere it fails the depth
> buffer test and that will effectively "clear" the stencil bits so decal2
> will not show up at all.
>
> ->
> ->Eye decal1 & Base1 decal2 & Base2
> -> | |
> -> | ||
> -> | ||
> -><) || ||
> -> || |
> -> | |
> -> | |
> ->
> ->With one stencil bit this problem is unavoidable.
>
> The only case where you get into trouble is if a decal overflows
> its base because then the base cannot set all of the proper stencil
> bits and the base may hit junk set by previous bases. So, decals
> must lie completely within their base poygons.
>
>
>
> src.
>
>
> --
> -----{-----{---++at++ -----{----{---++at++ -----{----{---++at++ -----{----{---++at++
> Sharon Rose Clay (Fischler) - Silicon Graphics, Advanced Systems Dev.
> src++at++sgi.com (415) 933 - 1002 FAX: (415) 965 - 2658 MS 8U-590
> http://www.sgi.com/Technology/Performer/
> -----{-----{---++at++ -----{----{---++at++ -----{----{---++at++ -----{----{---++at++
>-- End of excerpt from Sharon Clay
=======================================================================
List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/
Submissions: info-performer++at++sgi.com
Admin. requests: info-performer-request++at++sgi.com
This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:53:21 PDT