In article <jun### [at] ip68-97-75-252okokcoxnet>,
 jun### [at] grayproductionsnet (James Gray) wrote:

> Problem number one.  I really like the look of this, but I really want
> about 1/10th of the stars that are in here.  I've tried messing with scale
> and frequency, but I just haven't found the right way to make the stars
> appear less frequently in the pattern.

Try reducing the amount of color map that is non-black. Move the 
0.08-0.1 boundary further towards 1 in your map.


> Prolem number two.  My scene has plenty of ugly jaggies and thus really
> needs anti-aliasing.  Unfortunately, when I trace with that, at any of the
> different settings I've tried, I turn the above starfield into a solid
> black sky.  Is there no way to have both?

There really isn't a good way around this. The texture technique takes 
advantage of pixels being point samples, antialiasing samples an area, 
and the bright areas get drowned out by the larger dark areas.
The antialiasing code also clips colors to the [0, 1] range before 
averaging the colors for the final pixel color, so you can't just make 
individual extremely bright stars. (it does this to avoid jagged edges 
on extremely bright objects, in my opinion the fix is worse than the 
problem)

The most reliable technique seems to be to use spheres randomly 
positioned in a half-sphere around the scene, sized just big enough to 
always cover a pixel. This usually looks really ugly in my opinion, and 
is sensitive to the image size (though you could automatically 
compensate for that) but is resistant to antialiasing.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

Post a reply to this message