Re: [Algorithms] volumetric spotlight

[Jeff R. <je...@8m...>]

OP here, thought I'd share my results. Thanks to Miles in particular for
being helpful.

http://i44.tinypic.com/2h4algx.jpg

Determined the distance through the fog cone by tracing the eye vector to
the far side of the cone, then clipping that distance against the depth
buffer. With the entry and exit points inside the volume, it turned out to
be fairly easy to evaluate the falloff integral implicitly. All told
compiles into about 50 shader instructions, one texture lookup, and no
overdraw. I might be able to squeeze the shader down a little more, but that
will come later.

Thanks guys,

Jeff

On Sun, Mar 28, 2010 at 9:18 AM, Bert Peers <be...@bp...> wrote:

> Darren Grant schreef:
>
> > The most complex approach is to write a ray-casting shader that
> > integrates over distance travelled by each eye ray through the umbra
> > volume. It is hard to get the results to overlap and intersect correctly
> > with the rest of the scene unless you have some sort of unified
> > rendering architecture built around ray-casting. Very pretty if you get
> > it working, but very difficult to deploy without limitations coming back
> > to get you later.
>
> I'd give that a try too.  There's some good shadowmap based stuff in
> ShaderX7 as well for easier integration with scene geometry (p. 331).
>
>
> Also check out I3D10's update to Crytek's Light propagation volumes.
>
>
> hth,
> bert
>
>
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-- 
Jeff Russell
Engineer, 8monkey Labs
www.8monkeylabs.com