Re: coordinate system confusion

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Jaehong Ahn (totoro++at++chopin.kist.re.kr)
Thu, 10 Apr 1997 16:21:11 +1000 (KDT)


On Wed, 9 Apr 1997, Christopher R Volpe wrote:

> Hi Performers-
>
> The man page for pfLightSource gives the following piece of sample
> code:
>
> /* Time of day is high noon */
> sun->setPos(0.0f, 1.0f, 0.0f, 0.0f);
>
> Since the up direction is +Z (according to the Programmer's Guide page
> 95), shouldn't this code be as follows:
>
> /* Time of day is high noon */
> sun->setPos(0.0f, 0.0f, 1.0f, 0.0f);
>
> Is this a documentation error or am I misinterpreting something?
>
> thanks,
> Chris
>
> --
>
> Chris Volpe Phone: (518) 387-7766
> GE Corporate R&D Fax: (518) 387-6560
> PO Box 8 Email: volpecr++at++crd.ge.com
> Schenectady, NY 12301 Web: http://www.crd.ge.com/~volpecr
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>

Hi, Chris.

I think that is a documentation error.

I have document files for Performer programming which is developed by
Silicon Graphics. In the document, there's a example code for adding
lighting (Page 6-30). It is as follows.

         /* high noon */
         pfLightPos(sun, 0.0f, 0.0f, 1.0f, 0.0f);

Now ... \|/
                          --O-- Sun
                           /|\
   

                            o
                           /T\ Me
                            H

Sincerely,

Jaehong Ahn

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