> You need double precision floating-point processing.  Sorry!
>
>     Thorsten


What if... we limited the scene extents (in a seperate
version of POV-Ray, of course) to some small volume
like 1024 cubic units where single-precision floats
would be more viable? One could only render small scenes
or single objects, but when developing single objects
(like people or cars), that's acceptable.

The Tachyon raytracer
http://jedi.ks.uiuc.edu/~johns/raytracer/
has an option to build using
single precision (I imagine typedef'ing POV's DBL type
to float instead of double would be analogous), and
its author reports a 5-20% speed increase even without
hardware leveraging. He had to customize his epsilon
constants but I think it shows that using single precision
is possible. If I was modeling a chair or whatever,
I wouldn't turn down any speed improvement, even if
the occasional triangle had a gap.

POV's bounding slab bbox are already single-precision,
interestingly. BBOX_VAL is type SNGL.


Ray Gardener
Daylon Graphics Ltd.
"Heightfield modeling perfected"
http://www.daylongraphics.com

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