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From: markv@gauss.Princeton.EDU (Mark VandeWettering)
Newsgroups: comp.sys.sgi
Subject: Interpolating Colors in Lighting Mode?
Message-ID: <3801@idunno.Princeton.EDU>
Date: 2 Nov 90 19:40:21 GMT
Sender: news@idunno.Princeton.EDU
Reply-To: markv@gauss.Princeton.EDU ()
Organization: Princeton University
Lines: 25

Is there any way to make the SGI interpolate colors AND perform shading
calculations at the same time?  For instance, if I am drawing triangles
and wish to interpolate the colors, I do something like:

	lmcolor(LMC_DIFFUSE) ;

	....

	bgnpolygon() ;
		n3f(normal) ;		/* some normal for the poly	*/
		c3f(c1) ;		/* a color + vertex */
		v3f(v1) ;
		c3f(c2) ;		/* a color + vertex */
		v3f(v2) ;
		c3f(c3) ;		/* a color + vertex */
		v3f(v3) ;
	endpolygon() ;

But the resulting triangle, while shaded, only has a single flat color.

Any ideas?

mark (markv@acm.princeton.edu)
Mark VandeWettering
markv@acm.princeton.edu