For lighting (rather than reflection mapping) you would not need more than
the brightest 10% of pixels in the image, these could be lights behind a
translucent sphere that held the matching image map so that you still had
reflection/environment mapping. The lights would need to be directed at the
center of the sphere so as to avoid them illuminating the dark parts of the
map/sky.
 
John Pallett wrote:

> That's a good idea - though I'd hate to think of the number of lights
> created for a 1024x768 image... :)
> 
> I'm wondering if there's a way to crank up the ambient value of the sky
> sphere, perhaps after darkening the 'dark' parts of the image, so that the
> end result is an approximation of an HDR radiosity solution.  Right now
> when I use a sky sphere, it gives a nice effect, but the effect is too
> subtle.
> 
> Perhaps adjusting the contrast (keep the bright parts bright, darken the
> rest) of an image, then setting its ambient value to 10, would do the
> trick
> and could simulate an HDR image.  I'll have to experiment, it probably
> depends upon which image is used.
> 
> JP
> 
> 
> "Daniel Matthews" <dan#@3-e.net> wrote in message
> news:100### [at] 3-enet...
>> Something more complex than mapping the image to a sky sphere?
>> Such as converting the image to an array of light sources distributed
>> over
> a
>> sphere? There are examples of both pixel data to object conversions and
>> spherical distribution of objects, you will need to look through the
>> older news post to find them, both are in the last 6 months.
>> There is also a Lighting inc that could be upgraded to perform such
>> lighting.
>>
>> John Pallett wrote:
>>
>> >
>> > Is there a way to coerce POV-Ray 3.5 into doing this without the patch?
>> > Perhaps a pre-processing step on the HDR image and then the appropriate
>> > radiosity parameters?
>> >
>> > JP
>> >
>> > "Gilles Tran" <git### [at] wanadoofr> wrote in message
>> > news:3e04e8bf@news.povray.org...
>> >> Here are some tests of the HDRI (high dynamic range illumination)
>> >> patch by Mael.
>> >> The model is the Lego Ferrari by Kenneth Storm (see  the p.b.i thread
>> > "Lego
>> >> Ferrari" on Sept 2).
>> >> The HDR maps are those available at Paul Devebec's site (I put the
> probes
>> >> name for reference) http://www.debevec.org
>> >> There's nothing much to it actually : just the HDR map, no lights,
>> >> same standard radiosity parameters. There are some visible artefacts
>> >> in the
>> > maps
>> >> that have many strong light sources (like the Galileo probe), but the
> way
>> >> the HDR map seems to replace light sources is really amazing (apart
>> >> the
>> > lack
>> >> of specular highlights, of course).
>> >> I still have to test it on "real" scenes though, where the
>> >> illumination
>> > also
>> >> comes from regular objects. I really can't take credit for anything in
>> > these
>> >> tests ! Before I tested it, I couldn't figure out whether HDRI was
> really
>> >> better than plain radiosity, but it really is.
>> >> Important note : the patch is not publicly available yet (there's a
>> > Megapov
>> >> version somewhere) but I hope that Mael will release it soon.
>> >>
>> >> G.
>> >>
>> >> --
>> >> **********************
>> >> http://www.oyonale.com
>> >> **********************
>> >> - Graphic experiments
>> >> - POV-Ray and Poser computer images
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>> >>
>> >>
>> >>
>> >>
>>
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