In article <web.3e584037721c254a4b6c463e0@news.povray.org>,
 "halley" <e d @ h a l l e y . c c> wrote:

> I've always wanted a smarter mosaic previewer.  Here are some ideas.

Some interesting ideas here.


> * Instead of walking pixels/tiles in left-to-right-top-to-bottom order,
>   consider letting the renderer have a queue of higher priority pixels/tiles
>   which are rendered immediately in the order they're added to the queue.
>   Whenever the queue is empty, it should behave as it currently does.
>   It should still avoid calculating any pixel more than once, of course.

Or do a scatter render, picking the tiles from a randomized list.


> * Wherever a pixel or tile is very different from its neighbors' colors,
>   say, a red tile found amid several mostly white tiles, recurse an extra
>   level in that region to give the viewer a little more definition along
>   the natural edges of the image.

I like this idea...kind of falls in with some ideas I've had about 
progressive antialiasing/focal blur.


> * Wherever the user clicks in the preview window, enqueue a few more pixels
>   to be rendered on a priority basis in that area.  I suggest enqueueing a
>   random spray in a circle of a few pixels around the mouse click.  This
>   will let the user "paint" an area to be previewed first, extremely
>   helpful to check if a part has just the right angle or material, before
>   the render goes ahead and fills out the sky and other areas.

This one is highly platform-dependant though. Possible to abstract out 
of the core code, though.
The code could also be modified to reuse the mosaiac samples for the 
final render. The only pitfall is that it will require the entire image 
and quite a bit of additional data to be kept in memory, which can 
consume a pretty big chunk of RAM. You could do some fancy file writing 
code to keep the main file on disk, reading and writing small tiles, or 
just disable mosaiac preview if it goes above a certain memory use 
threshold.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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