Scott Herod (herod++at++aspen.evt.com)
Thu, 22 Apr 1999 14:59:26 -0600
I have discovered that you need to be careful with PFTR_ON
on IR. Apparently it defaults to screen door transparency
which has only a few (9?) levels. Fading with it causes
noticable jumps in transparency level.
Scott Herod
Simon Mills wrote:
>
> I also needed to fade in/out parts of my scene loaded from *any*
> database file. My method was to:
>
> - Set up node pre/post draw callbacks to set override of transparency
> on/off.
> - Use a traverser to set the alpha component of each geoset colour array
> under a given node. Blend in any alpha contained in transparent
> materials so these fade correctly.
>
> This is slightly different to what Brian wrote below with setting the
> pfGeoState transparency on. I tried this also but it makes a permanent
> change to the geometry (unless you go to the bother of remembering the
> setting for each pfGeoState you use). For me it messed up the order of
> rendering so I got artifacts. Also my database shared pfGeoStates with
> parts that should not fade.
>
> However my method is not perfect since the ordering by transparency done
> by the cull stage doesn't seem to take the above into acccount. So I get
> rendering anomalies during fade. Does anyone know a way to fix this?
>
> P.S. I was working on Octane MXE. On Onyx2 iR you can use multisample
> transparency to get around this.
>
> Hope it helps, Simon.
>
> Brian Furtaw wrote:
> >
> > You'll need to enable transparency (blending) for the fading models
> > pfGeoState's. To do this call pfGeoState::setMode(PFSTATE_TRANSPARENCY,
> > PFTR_ON). Also look at the pfTransparency() call to determine what quality of
> > transparency you are interested in.
> >
> > Brian
> >
> > On Apr 19, 12:29pm, Gary Quinn wrote:
> > > Subject: Howto Fade Models
> > > Hi all.
> > >
> > > I'd like to be able to fade models in and out of
> > > view, something along the lines of in/decreasing their
> > > transparency or alpha values.
> > >
> > > There doesn't seem to be anything documented, and
> > > I've tried changing geometry set alpha values -
> > > but that doesn't seem to do anything.
> > >
> > > A similar question was posted in Feb 1997,
> > > but there wasn't enough detail in the answer
> > > for me to implement the solution - which I didn't
> > > fully understand anyway :-(
> > >
> > > Can anybody help please.
> > >
> > > Cheers,
> > > Gary.
> > >
> > >
This archive was generated by hypermail 2.0b2 on Thu Apr 22 1999 - 13:59:37 PDT