Re: RGBA with 8 samples on IR

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Orad Hi-Tec Systems (orad_u++at++netvision.net.il)
Thu, 10 Oct 1996 09:39:28 +0300

Remi Arnaud wrote:
>
> Here is a message from Ziv Gigus <ziv++at++argus>
>
> IR's hardware was designed to support either 10 bit RGB (no A) or 12
> bit RGBA. It was never designed to support 10 bit RGBA and no future
> flavour of IR ever will.
>
WHY !?
As was mentioned, the alpha in the framebuffer is mostly needed by
applications in a video environment. Highest quality digital video
is 10 bits, never 12. (Also on the monitor side, it was mentioned that
the DACs dither to 10 bit). So what is really needed is 10 bit RGBA,
not 12 bit RGBA.

> Due to bugs in imp8 it can not support 8 samples RGBA (12 bit). It
> does support 8 sample RGB (10 bit) which are advertised in all pixels
> depths.
>
What is imp8 ?
Is it a ucode release? A hardware release?
a programmable-hardware release?
Is it now fixed? Is it in the process of being fixed?
How will customers get this fixed?

> Finally, note that both on IR and RE we dither glSampleAlpha(...) over
> 4 pixels, so with N samples you get 4N + 1 levels. This is done not
> done for AlphaToMask, however.
>

Is this a bug or a feature?

Moshe Nissim
Orad Hi-Tec Systems
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