Re: pfLayer's & .flt

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Marcus Barnes (marcus++at++multigen.com)
Tue, 30 Jan 1996 13:03:33 -0800


On Jan 30, 2:02pm, Robert Webb wrote:
> Subject: Re: pfLayer's & .flt
> Marcus Barnes <marcus++at++multigen.com> wrote:
>
> > On Jan 30, 1:28am, Angus Henderson wrote:
> >
> > > Does anyone know why the Performer2.0 "perfly" correctly renders a
> > > sub-polygon form a MultiGen .flt file, yet the Performer2.0 "complex"
> > > does not.
> > >
> > > I looked for a different load flag or frame-buffer config but found none.
> > >
> > > It doesn't seem to matter whether I compile for GL windows or X windows
> > >
> > > ANgus
> > >-- End of excerpt from Angus Henderson
> >
> > perfly calls pfdCombineLayers() after files are loaded, while complex does
> > not. This changes the pfLayer modes from PFDECAL_LAYER_FAST to
> > PFDECAL_LAYER_DISPLACE.
>
> Hmm, OK, so why doesn't PFDECAL_LAYER_FAST work?

Sorry, I read that off of the pfdCombineLayers man page. It's in error.
It really forces the layer mode to PFDECAL_BASE_DISPLACE for any layers that
are BASE_FAST or BASE_DISPLACE, according to 2.0MR pfdLayer.c .

Odd ... it used to force (PFDECAL_BASE_DISPLACE | PFDECAL_LAYER_OFFSET).

> We had the same problem.
> The loader shipped with 2.0 caused all the Decal layers to flicker randomly.
> I know FAST may not be as good quality, but I'd still expect it to have
> _some_ effect, yet it does not appear to (if that's really what the loader
> is using).

Yes. FAST is the default. You can call pfdConverterMode_flt( PFFLT_LAYER,
PFDECAL_BASE_* ) to tell the loader to use any pfLayerMode. From perfly's
command line use "-y flt,9,6" to choose BASE_STENCIL for instance. This is the
only mode that works all of the time; but cost about 40% on RE2. SGI has been
trying to develop a faster method that works well and PFDECAL_BASE_DISPLACE |
PFDECAL_LAYER_OFFSET is the result of that effort.

> Doesn't matter how close you get to the Decals, or how you set
> your clipping planes, they still flicker the same.

In my experience, FAST (formerly equivalent to DISPLACE) only works well when
the near/far clipping planes are close together and the near plane is greater
than 1.0. It also helps to have a 32bit Z-buffer configured.

>-- End of excerpt from Robert Webb

As to the problems with pfLayer/pfDecal in 2.0 ... I know there have been many
over the life of the beta. I don't know if the problems are all fixed in the
2.0 release.

Regards.

--
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