On 1/10/2010 02:25, tth wrote:
> Did you mean that POVray keep the full generated picture in memory
> when rendering it ?

Generally, yes. This is not optimal for huge renders, but for the types of
ones most users do it's an optimization that increases speed. Keep in mind
that as the SMP version of POV-Ray can render portions of the image out of
sequential order, it would complicate the image code quite a bit if we had
to be able to create the image in advance and then read and write any
arbitrary block (this is doubly so for files that use compression), and
would have a performance impact due to all the disk I/O.

We could cache the data to an intermediate file in raw format (and in fact
there is some code in there for this, however it's not currently working
properly), but while that bypasses the issue of the image file format, it
still leaves us with the I/O penalty.

Ideally we'd have an INI option to tell POV when to stop using RAM and
start using disk for the temporary image cache, however at this point there
is no setting for it.

-- Chris

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