Re: Transparency problem

New Message Reply Date view Thread view Subject view Author view

Dirk Reiners (reiners++at++ecrc.de)
Mon, 8 Sep 1997 22:17:29 -0600

On Sep 5, 11:23am, Prakash Mahesh wrote:
> Subject: Transparency problem
> Hi,
>
> We are having a problem with transparency. We have two objects, A and
> B, A has a transparent texture and is in front of B. As we move the
> scene around, at certain angles, the parts of B behind the transparent
> areas of A also disappear. We think it may be some kind of drawing
> order problem involved with z-buffering. We don't do the actual
> drawing, that is handled in perfly, is there some way to stop this from
> happening in the scene definition?
>
> Thanks.
>-- End of excerpt from Prakash Mahesh

One solution that you can use if your transparent texture is of the 0%/100%
variety is activating the alpha test. See glAlphaFunc for details. Pro:
Sort-independent. Con: Multisample AA doesn't work for this (as the texture is
only evaluated once per pixel), so the edges of your textured objects will
alias.

Hope it helps

        Dirk

-- 
-- Dirk Reiners                 reiners++at++ecrc.de, reiners++at++igd.fhg.de  
-- ZGDV - AR Group                   http://www.igd.fhg.de/~reiners
-- Arabellastr. 17 (ECRC)             
-- D-81925 Muenchen                  All standard disclaimers apply. 
-- Truth is stranger than fiction because fiction has to make sense. 
=======================================================================
List Archives, FAQ, FTP:  http://www.sgi.com/Technology/Performer/
            Submissions:  info-performer++at++sgi.com
        Admin. requests:  info-performer-request++at++sgi.com

New Message Reply Date view Thread view Subject view Author view

This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:55:54 PDT

This message has been cleansed for anti-spam protection. Replace '++at++' in any mail addresses with the '@' symbol.