Re: lights problem

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Sharon Clay (src++at++rose.asd.sgi.com)
Sat, 8 Mar 1997 00:15:56 -0800

+>---- On Mar 7, 8:41am, Brian Furtaw wrote:
> Subject: Re: lights problem
->
->This is just a wild guess but give it a try. Create the root node of your scene
->graph (pfScene) then create two groups (pfGroup) and below each group a light
->source and any geometry you want lit by it.

Good guess but pfLightSources are only completely global in effect.
The reason that we do this is becuase you frequently want to
put a light in a scene graph to position it but then position location
can much different from the geometry that you want it to light.
Cosmo3d has the right solution to ths problem with a separate
environment node to express effect. In Performer, we went for the
simple common-case soln: position in scene graph of pfLightSourcs
controls position of the light and such lights are global.

If you want to have lights be turned on and off for different
geometry, use libpr pfLights and express this fact with the
LIGHTS array in pfGeoStates.

src.

->On Feb 21, 9:49am, Jerzy Galus wrote:
->> Subject: lights problem
->> Hello everyone,
->>
->> I have the following problem:
->>
->> Let's say that we have a scene with some geometry nodes and two
->> lights attached to it. My question is :
->> is it possible to render part of the scene lit with two lights
->> and part with only one light ?
->> I'm using Performer 1.2 on RE2 (Irix 5.3).
->> Thaks in advance,
->>
->> --
->>
->> Jerzy Z. Galus gacek++at++ai.com.pl
->> MP-PZL Aerospace Industries
->> Al. Krakowska 110/114 tel : (48-22) 846-59-61
->> 00-972 Warsaw (48-22) 846-54-17
->> POLAND fax : (48-22) 846-54-18
->>
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->>-- End of excerpt from Jerzy Galus
->
->--
->o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o
->
->Brian Furtaw (brian++at++sgi.com)
->VisSim Technical Consultant
->12200-G Plum Orchard Drive Office:(301)572-3293 Fax: (301)872-3293
->Silver Spring, Maryland 20904 OpenGL/ImageVision/OpenInventor/Performer
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-> Submissions: info-performer++at++sgi.com
-> Admin. requests: info-performer-request++at++sgi.com
->
+>---- End of excerpt from Brian Furtaw

-- 
-----{-----{---++at++   -----{----{---++at++   -----{----{---++at++   -----{----{---++at++
Sharon Rose Clay (Fischler) - Silicon Graphics, Advanced Systems Dev.
src++at++sgi.com  (415) 933 - 1002  FAX: (415) 965 - 2658  MS 8U-590
-----{-----{---++at++   -----{----{---++at++   -----{----{---++at++   -----{----{---++at++
=======================================================================
List Archives, FAQ, FTP:  http://www.sgi.com/Technology/Performer/
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