Re: the Sun

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Michael Jones (mtj++at++babar)
Wed, 2 Nov 1994 09:58:55 -0800

On Nov 2, 8:33am, ken sartor wrote:
> Subject: the Sun

:Does anyone out there know how to obtain the elevation
:angle and azmuthal angle (right ascention and declination?)
:for the Sun in perfly?

If you mean, what is the direction to the sun based on
the time-of-day GUI slider, then the answer is easy and
is found in common/env.c:

    /* Here we set the light position. Alternately we could use a pfDCS. */
    pfCombineVec3(t, tod, noon, 1.0f - tod, night);
    pfNormalizeVec3(t);
    pfLightPos(sun, t[0], t[1], t[2], 0.0f);

If you mean a more robust solar/lunar direction based on sidereal
time and observer lat/long then the short answer is that perfly
does not support this feature.

-- 


Be seeing you,      Phone:415.390.1455  Fax:415.390.2658 M/S:8U-590
Michael T. Jones    Silicon Graphics, Advanced Graphics Division
mtj++at++sgi.com         2011 N. Shoreline Blvd., Mtn. View, CA 94039-7311

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