Re: pfLightSource and performance ?!

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Rémi Arnaud (remi++at++remi.asd.sgi.com)
Tue, 6 May 1997 17:55:31 -0700 (PDT)

Niels Hilbrink wrote:
>
> Hi,
>
> I've got a question on the subject of pfLightSources.
>
> I noticed a performance drop of nearly 50% in using either a local or global
> lightsource. Is this normal ??
>
> I think its quite a lot. I mean there's nothing in the manual pages on this
> performance drop (yes there is something in there like that local lightsource
> "incur a performance penalty" but not 50%). So either I so something wrong (most
> likely scenario) or this is normal behaviour.
>
> Best Regards,
> Niels Hilbrink

 Local light source use a projective texture, alpha blending multipass algorithm.
 The whole database is send twice to the pipe, resulting in a nearly 50%
 drop of for performance.
 Global lightning is done through OpenGL lights. The performance hit
 depends on the number of lights that are turned on.
 You may want to try different number of light on your system to
 see the difference in performance.

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