Orchid XP v3 <voi### [at] devnull> wrote:
> Warp wrote:
>
> >   Testing against the same object in the next pixel and getting a hit
> > doesn't tell us anything. There could be another object in front of
> > the object at that next pixel, so it would have to be tested anyways.
>
> You are right of course - we still need to do more tests if we get a
> hit. But I'm wondering, does getting a hit allow us in any way to avoid
> testing objects "further away" than the one hit?
>
> (I don't know how POV-Ray's bounding and space partitioning works -
> especially the new octree thing. And obviously POV-Ray supports infinite
> objects and so forth...)
>
> --
> http://blog.orphi.me.uk/

Well ...

Thinking of it more than 5 seconds, it is so obvious that an (unpredictable
?)object can be interposed in front of the currently tested object and
therefore intercepted by the next ray and not by the previous, that I did
not even figure out the situation!!!

Of course my suggestion in nonsense!!

However, maybe my remark that the final image (ie once entirely traced ...)


quick pretrace of the scene (also with radiosity and shadow rays), make
some kind of geometrical analysis, and feed a predictor?

For an example and simplifiyng the situation, considering only primary rays,
make an undersampled pretrace of the scene (factor of 1/2), and determine
which objects were hit by each ray. Then, using this information, isn't it
possible somehow to predict for the pixel or sub-pixel level, and for
anti-aliasing?

Is there really nothing to do in order to predict more or less for
ray-object intersection? Is it really impossible to use statistical aspects
of a scene to speed-up intersection tests?

    Bruno

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