Chris Huff wrote:
> 
[...]
> Yes, because the rays "fan out" and are evenly spaced, the spacing gets
> larger with distance, similar to the way area shadows spread out.
> These artifacts should be less visible with more random backgrounds(the
> checker pigment used here really shows the problem because of it's
> repetitive nature).
> I suppose if the original algorithm is like media method 1, the current
> one is like media method 2. I have a couple ideas for anti-aliasing the
> blur:
> 1) Sample along 2 perpendicular directions, like the existing method 2,
> but super-sample between two samples when their difference in color
> exceeds a threshold. This would be sort of like media method 3...
> 2) Send rays out in a triangular pattern, dividing into sub-triangles
> when necessary. This would have the advantage of covering an area of
> space instead of sampling along two directions...the recursive triangle
> pattern might make the aliasing less noticeable, too.

How about combining geometric and random techniques, that would help adjusting
graininess, but i'm not sure if that's easy to implement.  

> 
> > BTW, I remember you working on some pattern blurring function, did
> > you have any results in that direction ?
> 
> I am planning to make another try, the first one wasn't very successful
> or easy to use(it used a 3D convolution matrix, which allowed effects
> other than blur, but was a pain to use and too slow with matrices large
> enough to get decently smooth blur. I plan to allow this and another,
> easier to use and faster method in my next try.). I am debating whether
> to blur patterns or pigments...probably both.
> 

I always thought a convolution matrix can only be applied to a rastered pattern,
at least you would have to specify some kind of scale factor for the matrix IMO.
If i understand things right, it's worth trying adaptive calculations (like used
with antialiasing) when working with a larger matrix.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/

Post a reply to this message