Re: PFDECAL_BASE_STENCIL

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From: Angus Dorbie (dorbie++at++sgi.com)
Date: 03/03/2000 12:41:28

Given your circumstancves I suggest you expore using the multiple draw
bins on the channel and explicitly specify their rendering order in the
draw callback.

Cheers,Angus.

Scott Herod wrote:
>
> Hello,
>
> I am looking at pfLayers as a way to handle not only
> Z-buffer fighting but also transparent layer depth sorting
> to avoid what I call alpha-cutting. I understand the DISPLAY
> mechanism and while it does help with the Z-buffer fighting
> it doesn't solve the alpha cutting.
>
> STENCIL layering also appears to fix the alpha-cutting problems
> ( at a noticable performance hit to my 02 ) but am I correct that
> it sets values in the stencil buffer as it draws each region and
> tests for the higher layers. The problem is that my second layer
> is only drawn when it is explicitly over the bottom layer. It would
> be nice if I could also force it to draw when the second layer is
> not over the bottom layer. Is that possible?
>
> More details. I'm guessing that STENCIL layering happens as follows.
> Draw the bottom layer writing appropriate values into the depth-buffer
> and TRUE's into the stencil buffer. Draw the second layer by testing
> the values in the stencil buffer and ignoring the depth buffer. Write
> some appropriate values into the buffers. Repeat.
>
> What I would like to do is draw the second layer if the stencil
> buffer test passes OR the depth buffer test passes. Possible? Or
> do I just need to do all sorting and testing myself?
>
> Thanks,
>
> Scott Herod
> herod++at++rtset.com
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-- 
For Performer+OpenGL tutorials http://www.dorbie.com/
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After giving up raiding their neighboring countries the Norse men
have taken to raiding 15 year old kids in their bedrooms. Very sad.

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