Re: Alpha and anti-aliasing...

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Moshe Nissim (moshe++at++orad.co.il)
Sat, 09 May 1998 14:56:19 -0700


Angus Dorbie wrote:

> You have the option of using blended transparency instead
> which will introduce the classic zbuffer alpha occlusion
> problems unless you sort in the cull process.
>

Keep in mind that the cull process distance-based sorting is done
based on the objects' centers of their bounding spheres. On the other
hand, zbuffer is pixel-based. So this sorting will work correctly
for some types of scenes, but not for others
(objects are small compared to inter-object
distances, no complex depth-interactions between objects, etc.)
Alas, the classic zbuffer alpha occlusion problem cannot be completely
solved on zbuffer-based rendering hw.

> You could also use more multisamples to increase the
> number of multisamples and therefore the number of
> shades of alpha.

But if you need framebuffer-alpha (not to be confused with
material/object/texture alpha), don't try to increase the
 number of multisamples.
  
Bye,
Moshe

----------------------------------
Moshe Nissim
Orad Hi-Tec Systems
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