Re: Layered Intensity Alpha sky texture.
John Rohlf (jrohlf++at++tubes)
Fri, 20 May 94 9:51:25 PDT
>
> Hi,
>
> I'm running Performer1.2alpha99 on an Onyx RE^2 (running Irix
> 5.2-ALPHA-1010931841).
>
> In Multigen our Intensity Alpha sky texture looks nice, but when we are
> running our database in Performer the skies looks like they are layered.
> It is the Alpha part of the texture which is layered. There are just a few
> transparency levels.
>
> In Multigen I tried to change the Internal format, from the default format
> to TX_IA8. Then I would still have a full speed texture, but with 256 levels
> of Alpha.
>
> Again I tried to run our database in Performer. But still there where just a
> few levels of transparency.
>
> At last I changed the internal format to TX_RGBA12 on the sky texture in
> Multigen. Then I would have 4096 levels of Alpha. (The only difference was
> that the Intenity part of the texture became blue in Multigen.) In Performer
> the Intensity part became blue (as in Multigen), but there where still just
> 16 transparency levels.
>
> The last test is an indication that this problem has no origin in LoadFlt,
> since the Intensity part of the texture became blue in Performer.
>
> My question is:
> Doesn't Performer allow you to have Intensity Alpha textures with more than
> 16 transparency levels.
>
> If Performer allows more than 16 transparency levels:
> What can I do to get skies with more than 16 transparency levels
> TX_IA8 (256 transparency levels) will satisfy our needs for credible skyes.
>
The default Performer transparency mechanism uses multisampling
(see msalpha) for best performance. However, this looks worse than
the slower blendfunction type transparency. What you need to
do is specify the higher quality transparency for
your sky. Find the gstate in question and:
pfGStateMode(gstate, PFSTATE_TRANSPARENCY, PFTR_HIGH_QUALITY);
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on Mon Aug 10 1998 - 17:50:17 PDT