I got it to work by putting a small sphere around the camera, double
illuminating it, and hacking the source so that it calculates phong on
the reverse side.  Works pretty good except for the point nature of the
light makes it blink on and off rather suddenly.  There's an animation
in p.b.a

-Mike

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Mike <Ama### [at] aolcom> wrote:
> I was pondering how to do this and the clouds, sky, and sun are easy
> enough to do.  The only thing left was the lens flare and sun glow, but
> notice that in the cloud program the flare and glow vary with the sun
> intensity through the clouds.  Could post_process read the filter value
> of the sun through the clouds and use this to adjust the intensity of
> those?

A while ago I created a cloud animation that includes a sun lens effect,
with the brightness affected by the cloud density (~400 Kb AVI):

   http://www.geocities.com/ccolefax/movies/clouds.avi


The simple technique seems to work quite well, giving a glow around the
cloud edges, and leaving the sun disc itself visible through thick cloud,
when the rays and glow are not.  No doubt more complex flare effects could
be created using MegaPOV's features, but the original animation would just
about render in POV 3.0.

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In article <39932539.F6B6D11C@aol.com>, Mike <Ama### [at] aolcom> 
wrote:

> I got it to work by putting a small sphere around the camera, double
> illuminating it, and hacking the source so that it calculates phong on
> the reverse side.  Works pretty good except for the point nature of the
> light makes it blink on and off rather suddenly.  There's an animation
> in p.b.a

Could you share this "hack"? In my opinion, the lack of highlight 
effects on the reverse side of a double_illuminated object is a bug.

-- 
Christopher James Huff - Personal e-mail: chr### [at] maccom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://homepage.mac.com/chrishuff/
TAG Web page: http://tag.povray.org/

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> Could you share this "hack"?

Comment out this conditional part from do_phong

if (Cos_Angle_Of_Incidence > 0.0)
  {
  }

If you look near the top of lighting.c, you'll notice that phong,
specular, and other functions execute if the object bears the
double_illuminate flag, the highlights are just skipped inside each
function if the light is behind the point.

-Mike

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