Angus Dorbie (dorbie++at++sgi.com)
Wed, 21 Jul 1999 10:33:16 -0700
They are just a read of the depth buffer so drawing the scene from the
light source and reading the depth buffer is how you'd get the map. They
are generated just before the drawing the channel in the draw process
and are copypixel'd to texture memory from the framebuffer. If you want
REALLY high resolution you'd perhaps use several asymmetric frusta.
The call to increase shadow map resolution is ALREADY supported but
there are limits to how high it will go and the higher the slower mainly
due to the readback time for the depth image, if nothing is moving in
the scene and the light is fixed you can readback the depth image once
and animate moving the eye without the readback overhead.
pfLightSource::setVal(PFLS_SHADOW_SIZE, resolution);
Just make sure the window is large enough because obviously you need
space for the shadowmap viewport.
Cheers,Angus.
Jorge Valencia Loera wrote:
>
> Hi pf's,
>
> Does anybody know when exactly the shadow map projected onto the scene by
> Performer to cast shadows is computed?? in the APP, CULL or DRAW? I think
> it's just before the DRAW isn't it?
>
> Has anybody had success reading the shadow map?
> I mean, is it possible to read the shadow map content in memory? and
> eventually save the content as a texture file? ( something like
> pfTexture::saveFile(char *fname) )
> Or how can I read the z-buffer of a scene generated from the light source
> viewpoint and create a texture with the z-buffer content?
>
> The point of doing that is that I want more resolution for my texture than
> what Performer is giving (using a 512x512 shadow map) so I want to try to
> process the shadow map maybe to render a scene with possibly non-realtime
> realistic results.
>
> Is somebody generating shadows in Performer with another technique than
> shadow maps?
>
> Thank you.
> Jorge
>
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This archive was generated by hypermail 2.0b2 on Wed Jul 21 1999 - 10:33:22 PDT