Re: [Dri-devel] radeon: two-sided lighting issues

[<si...@hi...>]

On Fri, Oct 11, 2002 at 06:00:18PM +0100, Keith Whitwell wrote:
> Felix K=FChling wrote:
> >On 11 Oct 2002 18:15:08 +0200
> >Michel D=E4nzer <mi...@da...> wrote:
> >
> >
> >>I was looking into the lighting issues Felix reported with the
> >>xscreensaver pulsar hack (when running it with the -light option). One
> >>side of the planes looks good, the other one is black, so I thought it
> >>might be related to two-sided primitives.
> >>
> >>Indeed, the hardware TCL code has a fallback for this if the material is
> >>different on both sides. If I hardcode that to always trigger (in
> >>check_twoside_fallback() in radeon_state.c), pulsar looks good with
> >>lighting.
>=20
>=20
> I think this is effectively the same as setting 'R200_NO_TCL=3Dt'.
>=20
> >>So I thought I'd see if this was related to some lighting oddities in
> >>bzflag, and I made another interesting discovery: with this fallback, it
> >>locks up the chip when connecting to a server, like I reported before
> >>for software TCL.
> >>
> >>In summary, there seem to be multiple problems related to two-sided
> >>lighting in the radeon driver, both with hardware and software TCL. I'll
> >>keep looking into them, but I hope this information will help someone
> >>else find them more quickly.
> >>
> >
> >One observation which confused me was that it looked good if I set the
> >alpha channel of global ambient to something other than 1.0 (or was it
> >0.0?)
>=20
> Which makes me wonder if it's a codegen/vtxfmt problem -- what happens wi=
th=20
> R200_NO_VTXFMT=3Dt ?
>=20
Any chance this might be similar to the FlightGear lighting problems
me and a few other people have been seeing for ages? RADEON_NO_TCL
'fixed' that, but RADON_NO_VTXFMT made no difference . . .=20

Simon
(hoping for a solution to this, finally . . .)

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