From: Marcin Romaszewicz (marcin++at++asmodean.engr.sgi.com)
Date: 08/14/2000 17:24:51
The current shadowing algorithm does not use stencil at all, so you should
not see interaction between your stencil code and the performer multipass
code. For now, the shadow code relies on a GL_EQUAL function in the
zbuffer.
If you have two scenes, keep in mind that objects in one scene will not
cast shadows onto objects in the other scene, so if you're rendering both
scenes to the same window, only some of the objects will appear shadowed.
-- Marcin
On Tue, 15 Aug 2000, [iso-8859-1] Juan R. Sáenz-Diez (Yuri) wrote:
> Hi pfAll,
>
> I am trying to apply the shadow map capability of Performer to a scene
> with heavy use of stencil operations. However, I can separate that
> part of the scene and put it in a pfScene, and have another pfScene
> with the shadow map stuff (on a separate pfChannel that overlaps).
> This works when shadow map is not in operation in the second
> pfChannel+pfScene.
>
> Now, I read there is some incompatibility between shadow map shadowing
> and stencil operations. I would like to hear a final word on this. I
> can foresee some problems if the shadowed geometry is doing
> incremental changes to the stencil buffer due to multipass rendering,
> but in my case my shadow scene does none of those (no stencil
> operations at all, but there exists an 8 bit buffer for the first
> scene). I get a black rectangle on the lower left area of the common
> viewport, just like someone else described, where I can see some hint
> of what could possibly be the shadow map.
>
> So, finally, can one use stencil at all when shadow maps are present?
> Should I look into some other shadowing algorithm instead? Should I
> look further into my own code because it is me screwing it all instead
> of the stencil operations or buffer?
>
> Any hints (or as I said, a final statement on this) would be greatly
> appreciated.
>
> Best pfRegards,
> Yuri.
>
>
>
>
> ----
> Por favor, acuse recibo -- Please acknowledge receipt
> ----
> Juan R. "Yuri" Sáenz-Diez
> Vis-Sim & VR Consultant
> +34 630 815 772
> jrsdm++at++acm.org
>
>
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