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On Thu, 27 Jan 2000 07:34:49 -0500, Chris Huff wrote:
>In article <388fdfd1@news.povray.org>, "Bob Hughes"
><per### [at] aol com?subject=PoV-News:> wrote:
>
>> Another triumph. This particular render could presumably be approximated
>> with
>> normals and a gradient y texture map, but this seems to be the answer for
>> doing anything with translucence hopefully.
>
>No texture map would be needed, but heavy anti-aliasing would probably
>have to be used. Normals are still more versatile, I have been trying to
>think of ways to use patterns to make directional blurring.
Okay, this is going to go into serious theoretical-land, so I've xposted
and set followups to .programming.
Ideally, we wouldn't need special code for blurred reflections or for
blurred transmission. What I'd like to do is implement ray differential
tracing (http://www-graphics.stanford.edu/papers/trd/) and make it possible
to set a flag on _any_ texture that causes it to automatically average
a specified number of samples for ray footprints over a specified size.
Such a flag would allow you to do blurred reflection or transmission
by way of setting a microfacet normal and doing averaged samples for
even very small footprints. One advantage would be that you could
use normal maps or other existing features to impart a pattern to the
frosted texture, or manipulate the microfacets to bias the frosted
effect to a particular direction. It'd also make checkered floors do
their own AA in the distance without having to do AA on the scene in
general.
Another nice feature would be a "footprint-size-map" that selects a
simpler version of the texture for different footprint sizes, so a
checkered plane in the far distance could just blend to medium gray
which could be sampled faster (but would still look right through
a telescope.)
--
These are my opinions. I do NOT speak for the POV-Team.
The superpatch: http://www2.fwi.com/~parkerr/superpatch/
My other stuff: http://www2.fwi.com/~parkerr/traces.html
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