Re: fog color

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Angus Dorbie (dorbie++at++sgi.com)
Wed, 18 Mar 1998 13:00:34 -0800

If you change fog color downstream in the draw then you
run the risk that the fog color from the app will clobber
your results next frame. Not a good plan unless you modify
it before drawing _every_ frame. Same goes for other similar
info.

Modify fog colour in the application process and use
multiple fogs if you need variety. Note this needs to be
the performer app, not the keyboard process, cull process
or draw process, but the application which ran through
the pfConfig.

Cheers,Angus.

crakrjak++at++xerxesinc.com wrote:
>
> i call this in my X input event loop when 't' is pressed:
>
> if (fogColor)
> {
> pfFogColor (shared->fog, 1.0, 1.0, 1.0);
> fogColor = 0;
> printf("white\n");
> } else
> {
> pfFogColor (shared->fog, 1.0, 0.0, 0.0);
> fogColor = 1;
> printf("red\n");
> }
>
> but this doesnt work, just calling pfFogColor(); doesnt change the color
> of the fog, the fog stays to the original color, maybe i have to change
> the color in a certain callback? or call another function after changing
> its color, i tried calling
>
> pfApplyFog(shared->fog);
>
> after setting the color but it still dont work, so if someone understand
> what im doing wrong please let me know.
>
> On Tue, 17 Mar 1998, Angus Dorbie wrote:
>
> > crakrjak++at++xerxesinc.com wrote:
> > >
> > > i'd like to know if its possible to change the fog color while my program
> > > is running, and if possible where can i change the color of the fog. Your
> > > help would be appreciated, thank you.
> >
> > pfFog::setColor
> >
> > This is in the manual, which should be the first place you look.
> >
> > Cheers,Angus.
> >
> > --
> > "Only the mediocre are always at their best." -- Jean Giraudoux
> >
> > For advanced 3D graphics Performer + OpenGL based examples and tutors:
> > http://www.dorbie.com/
> >
>
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-- 
"Only the mediocre are always at their best." -- Jean Giraudoux 


For advanced 3D graphics Performer + OpenGL based examples and tutors:
http://www.dorbie.com/
=======================================================================
List Archives, FAQ, FTP:  http://www.sgi.com/Technology/Performer/
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