Re: Transparency on iR??

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Marcus Barnes (marcus++at++multigen.com)
Fri, 18 Oct 1996 10:55:11 -0700

On Oct 18, 4:50pm, Edward Patel wrote:
> Subject: Transparency on iR??
> Hi Performers,
>
> Having a slightly strange effect on an iR and on a High Impact but not on our
> RE2. Maybe someone have noticed some similar stuff?
>
> We have a .flt model of a city. When we get to a crossing we can see the
> roadmarkings through some of the houses when using the OpenGL perfly. This
> don't happen on our RE2...wonder why?? The roadmarkings is done as a textured
> subface of the road...are we missing a patch??
  ^^^^^^^

This means that a pfLayer node is created that has your subface as a decal
child. The texture apparently has alpha? so you are dealing with a couple of
problem areas:

o 2.[01] PFCULL_SORT conflict wrt decaled, transparent geosets. I have test
databases that show this problem (I sent one to SGI months ago along with a bug
report). I suspect that this is your problem. See the pfChannel(3) man page:

""
     By default, the opaque bin rendering order is PFSORT_OPAQUE_BIN_ORDER (0)
     and the transparent bin is PFSORT_TRANSP_BIN_ORDER (1) so that
     transparent surfaces are rendered after opaque surfaces.
""

... but pfLayer/pfDecal is also trying to enforce some draw ordering and the
two mechanisms conflict with each other.

o 2.x pfLayerMode() doesn't work as well as it did in Performer 1.2 . The most
functional mode to use in Performer 2.[01] is PFDECAL_BASE_STENCIL . Try this
to see if it helps.

Regards.

--
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