> You do realise that the changes your are talking about are several hundred
> hours of work just to get started, not even to mention bringing them into
a
> "completely working" state?


That's definitely a good point.

I'm basically looking at it from a
"what does it ultimately cost to provide
the end solution" perspective. When I
consider my options, modifying POV-Ray
appears to be a good one. If there must
be considerable effort, then it should
be invested into something that returns
a strong multiplier effect.

I already have a simple scanline renderer
up and running inside my own product,
for example. I could just keep extending it.
However, to bring it to the same feature
level as POV-Ray in terms of scriptability,
support, and those other things I mentioned,
would take even longer. So even if modifying
POV takes effort, it's the lesser of
two evils, so to speak. I have to consider
all the time that will be saved as well.
I also have to keep in mind that if the
idea is popular with other people, then
the work will be divided amongst several
developers. If I do a separate project,
it is far less likely to receive the
help of others.

There are benefits even from implementing
minimal functionality. For example, even if
texturing is not engaged, a scanline system
can rapidly preview the geometric size,
position, and diffuse lighting of objects.
So it is possible to break the work into
rewarding milestones.

I think the difficulty of implementing
scanline renderers has been historically
overstated, looking at some older posts.
Although they're certainly not as
simple as raytracers, once one has a
working triangle rasterizer, the rest
is straightforward. If one wants a REYES
algorithm using primitive splitting,
that's certainly more work, but splits
are not mandatory. And a triangle rasterizer
itself is not difficult: it's just a matter
of bresenham'ing the projected vertices
into right and left edgelists, and then
iterating between the edges.

I think it brings a bright future to
POV-Ray, in terms of being used for
more work in the film industry, where
scanline solutions are necessary to
help meet deadlines. It also means
"the rest of us" would have access
to these tools. Scanline systems can
also exploit video card hardware,
making certain scenes even faster to render.

Ray

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