Re: Transparency
John Rohlf (jrohlf++at++tubes)
Mon, 2 Oct 95 14:21:28 PDT
>
> I have seen similar problems when loading Multigen models which
> contain transparent parts (though i'm sure it will happen with
> other models, too). I think the problem is the order of rendering.
> I don't think Performer does any pre-sorting of transparent parts,
> and to get transparent parts to render correctly, they should
> probably be rendered after all opaque parts and sorted to render
> back to front. The MultiGen modeller allows priority to be applied
> to parts, this can change the order of rendering. I'm sure that
> something within Performer will let you assign higher priority
> to your transparent parts so they can be drawn last. I just don't
> know if you can sort them easily.
>
> Thom
> <---- Begin Included Message ---->
> Date: Fri, 15 Sep 1995 16:13:36 -0400
> From: Lynda D Myers <ldmyers++at++afit.af.mil>
> Subject: Transparency
> To: info-performer++at++sgi.com
>
> I am having touble seeing one transparent
> object through another when rendering objects
> in performer. Using the no_occlude option in
> pfTransparency did not solve the problem.
> Is there another way to do this?
>
> Thank you,
> Lynda D. Myers
> e-mail
> ldmyers++at++afit.af.mil
>
In 1.2, there was a bad interaction between pfLayers/pfDecal
and NO_OCCLUDE so you may be experiencing this with transparent layers.
Another situation is specific to multisampled, screen door transparency.
2 objects of equal transparency will use the same screen door so
even with NO_OCCLUDE you will only see the last-drawn transparent object.
To test this you can explicitly request PFTR_BLEND_ALPHA transparency
or vary object transparencies.
Performer 1.2 does draw transparent objects after opaque and
2.0 goes a step further by sorting transparent geosets back to front.
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on Mon Aug 10 1998 - 17:51:56 PDT