Orad Hi-Tec Systems (orad_u++at++netvision.net.il)
Thu, 27 Feb 1997 09:25:44 +0200
> Just for general reference, don't be too afraid to use blending,
> particularly if your objects are simple so that you don't need to
> sort amoungst them for proper results. Basic blending with
> smaller RGB visual sizes (such as 8 or 10) is pretty quick. In some
> cases it can even be faster because unlike the multisample mask
> techniques, it doesn't create complex pixels which can slow future
> rendering to those pixels.
>
This is interesting. Is there a "my samples are all the same" flag
on each pixel? And the rasterizer operates differently on such pixels?
This would imply that an opaque-first, transparent-last ordering with
multisample transparency is advantageous (vs. necessary for blended).
> ->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.
True, but they have their other wonderful uses (the only way to get
a second channel output from the Sirius).
Moshe Nissim
Orad Hi-Tec Systems
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