Please pardon me if somebody has already beaten this to death, but
an idea for anti-aliasing occurs to me.

It occurs to me that when a ray-intersection test takes place, the
instances where the test nearly succeeds, or nearly fails, can be
determined from the numbers comapared during the test.  If I am
correct, for instance, a b^2-4*a*c test is made for quadratics,
the values of b^2 and 4*a*c will be very close during the cases I
am drawing attention to, meaning that if a cone of rays covering
the pixel had been shot, instead of the one ray, some would have
hit the object and some would have missed, and more inportantly,
the relative proportions of these two groups of rays can be
calculated from the exact results of the ray-intersection test;
for instance, if b^2 exactly equals 4*a*c, we can say that the
ray intersects the surface at one point, and is tangential there
as well, and therefore half of the rays bundled around the tested
ray would miss, and the others hit.  If b^2 is slightly greater
than 4*a*c, then a greater number hit than missed, and so on.

This in turn leads to the idea that if this proportion is calculable,
the ray could be treated as if it had intersected the surface in
question, and another ray shot, ignoring the object in question,
and its results averaged with the intersecting ray, to give an
anti-aliased result.

It already sounds a bit complicated, but I just wanted to throw
the idea out there.

Regards,
John
-- 
ICQ: 46085459

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