Chris Huff <chr### [at] maccom> wrote:
: I'm not smoking anything...and what is wrong with wanting "parallel" 
: lights with soft shadows instead of parallel light that simply renders 
: slower?

  Parallel rays can't create soft shadows. With parallel rays each point
is hit by exactly 0 or 1 light ray. There's no way a single point could
be hit by more than 1 light ray when all the rays are parallel to each
other.
  Thus, you can't get soft shadows when only 0 or 1 light rays hits each
point.

: The alternative, a large area light positioned far away, could 
: cause precision problems.

  It's not an alternative since the light rays are not parallel in that
case. More than 1 ray can hit the same point and thus cause soft shadows.
  And besides, there's no difference between an area light located at
150 millions of km and 10 km (with equal apparent sizes) when the scene
is small (some meters wide).

: Parallel area lights can come close to 
: simulating that case, though they would never occur in the real world.

  "Parallel area light" is a completely wrong term here. If the rays are
parallel, they all go to the same direction, ie. are all parallel to each
other, and thus can't cause soft shadows.

  The light rays coming from the Sun are not parallel.

: Besides, people will expect having area lights to blur the shadows.

  Thus, it can't use parallel rays.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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