[GEM-dev] gem cvs alpha-depth bug?

B. Bogart ben at ekran.org
Mon Dec 1 19:06:33 CET 2003


When the "depth" object is in a gemchain lighting is not rendered properly.

(objects become hollow (ie reversed) with the front facing missing and the
lighting that of a hollow box)

now if depth turns off depth buffering this would explain it.

It would be nice to be able to make a box in gem that is properly
transparent (all the back faces being visible. with lighting on. Right now
if you just create a box without depth lighting works, but not all the sides
are transparent! (I imagine because of the render order of the faces) all
sides do become transparent with [depth] but then lighting does not work.

I really would be happy to drop all this render order nonesense. Objects
further back (in z) get rendered first. If the user wants to override this,
then then can specify a render-order with [tigger] or gemhead arguments.
This would simply be a lot more intuitive approach. (if its possible.)

Ben

----- Original Message -----
From: "guenter geiger" <geiger at xdv.org>
To: <ben at ekran.org>
Cc: <gem-dev at iem.at>
Sent: Sunday, November 30, 2003 2:20 PM
Subject: Re: [GEM-dev] gem cvs alpha-depth bug?


> On Fri, 28 Nov 2003 ben at ekran.org wrote:
> > I'm actually very fond of z-buffering
> >
> > could we "fix" lighting so that it works as expected with
depth-buffering on?
>
> What do you mean with "fix" the lighting ?
> Is there another problem I have overlooked ?
>
> Guenter
>
> >
> > Ben
> >
> >
> > > On Fri, 28 Nov 2003 ben at ekran.org wrote:
> > >> hey all,
> > >>
> > >> I just updated my gem cvs again today.
> > >>
> > >> I've noticed an odd bug with alpha (again). this time the alpha
object
> > >> seems to turn on depth buffering when its in the chain!
> > >
> > > Ooops, obviously my fault.
> > > I have changed default behaviour of alpha to the one it was in 0.87.
> > > Damn, I really forgot about that, ...
> > >
> > > It is not really a bug, but a feature that lets you use alpha blending
> > > independent from position, but the default behaviour should of course
> > > stay the same. Sorry ..
> > >
> > > Guenter
> > >
> > >>
> > >> I'm using lighting (because lighting tends to get messed up when
using
> > >> "depth" to show the effect. without a depth object in a chain, the
> > >> cube looks identical to its depth counterpart, as long as the alpha
> > >> object is in the chain. If I turn off the alpha object it works fine.
> > >> (looks as it does without using depth.
> > >>
> > >> Here is an example patch.
> > >>
> > >> Ben
> > >>
> > >>
> > >
> > >
> > > _______________________________________________
> > > GEM-dev mailing list
> > > GEM-dev at iem.at
> > > http://iem.at/cgi-bin/mailman/listinfo/gem-dev
> >
> >
> >
> >
> > _______________________________________________
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> > GEM-dev at iem.at
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> >
>





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