Re: Strange effect with alpha texture

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Mario Veraart (rioj7++at++fel.tno.nl)
Fri, 13 Feb 1998 20:46:25 +0100 (MET)

>
> Hi there!
>
> I experienced a very strange effect with alpha textures within perfly.
>
> Having a model of a car in as well .dwb as .flt file format with alpha textures
> for the windows of the car as well as for a driver inside the car depending on
> the angle I look at the car in perfly the driver is visible or not.
> It seems to be a problem with having a poly with alpha texture drawing against
> another poly with alpha texture because if I switch the texture of the driver to
> a non-alpha texture the driver is visible all the time.
>
> Has anybody out there already experienced something similar.
>
> This effect appears on an HighImpact with 4MB TRAM, Performer 2.0, OS 6.2 as
> well as on an O2 (Performer 2.0).
>
> Any help is very much appreciated.
>
> Christoph Tillack.

If you have the sorting enabled in the channel then it could be that
performer is putting these geosets in the transparent bin and
depending on de range to the viewer they are drawn back to front and
they update the Z-buffer. The non-alpha driver is put in the opaque
draw bin and that is drawn before the transparent bin.

Or if both are in the opaque bin then it could be a side effect of the
geostate (texture) sorting. Try to set the sorting of the opaque bin
to back-to-front sorting or something that doesn't sort based on
geostate.

Mario
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