Re: Multisample Masks
Moshe Nissim (orad_u++at++netvision.net.il)
Fri, 28 Feb 1997 14:55:01 -0800
Ran Yakir wrote:
>
> On Feb 26, 1:57pm, Sharon Clay wrote:
> > Subject: Re: Multisample Masks
> >
> > ->There is a *very* annoying SGI hardware bug which prevents the setup
> > ->of n=8 multisamples coexisting with alpha bit-planes (no such visual
> > ->exists). You can only do n=4 multisamples with alpha bit-planes.
> > ->This is *independent* of your framebuffer memory size (number of RM6
> > ->boards).
> >
> > Just to clarify to avoid possible confusion here, destination alpha planes
> > are not needed to implement the fade techniques discussed - they only use
> > source (in-coming) alpha.
> >
> So they do. However, in broadcast applications, using the Sirius, you use the
> alpha planes to send a mask for the chromakeyer, so that you can perform
> obstructions of real video by virtual objects, in the chromakeyer. This is the
> reason why we must use alpha bitplanes, and therefore suffer from this bug. I
> must agree with Orad on this matter - this is really a very annoying bug.
Thanks.
We have raised this problem when the iR came out, but judging by SGI's
response
so far, it seems that this is not a their priority. Maybe SGI doesn't
want to bother
with the broadcast market? Their marketing indicates otherwise ...
Anyone, please confirm/deny that this bug still exists in the Onyx2 iR.
BTW, was there any response that I missed on Ran's question/suggestion
regarding
multi-pass rendered nodes?
Bye,
Moshe Nissim
Orad Hi-Tec Systems
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on Mon Aug 10 1998 - 17:54:46 PDT