From: Angus Dorbie (dorbie++at++sgi.com)
Date: 03/31/2000 15:05:35
"Larry E. Ramey" wrote:
>
> Lo all,
>
> I would swear that I have heard or read this somewhere, but I can't find
> it.
>
> Does IR graphics cause the Opaque bin and Transparent bin to be
> combined?
No, but most transparent geometry is considered opaque because of tha
alpha to mask subpixel dither used instead of blended transparency.
>
> Can this problem be solved?
>
> Imagine 2 planes that form an X. Both are slightly transparent. How can
> I draw them so that where one is in front of the other I can see the
> other one behind it, and yet see the same thing when they switch?
You need to sort them appropriately, essentially a painters algorithm.
Multisample transparency won't show this because it's screen door, what
you have to do first is enable blended transparency, then you sort them
by depth, now you can turn depth sorting on for the transparent bin to
allow this on centers but that may not be good enough for you.
If not you might have to greate your own bins to force the draw order.
>
> The man pages I read seem to imply this is impossible since sorting is
> on a per GeoSet level instead of a perPrimitive basis.
Well if the planes were in the same geoset then it would be impossible
so it would be required that you split them into dofferent geosets.
Cheers,Angus.
-- For Performer+OpenGL tutorials http://www.dorbie.com/"In the middle of difficulty lies opportunity." --Albert Einstein
This archive was generated by hypermail 2b29 : Fri Mar 31 2000 - 15:05:58 PST