Hello,

I wanted to know if anyone had any experience using multiple very large textures
(> 2GB), and was able too keep povray from running out of memory.  Also, it
seems like POVRay loads textures to ram on parse - it it possible to keep
POVRay from loading the entire texture to ram at once?  A performance hit would
be better than dieing for lack of ram.

thank you,

Jacob

Post a reply to this message

"JSchloss" <nomail@nomail> wrote:
> Also, it
> seems like POVRay loads textures to ram on parse - it it possible to keep
> POVRay from loading the entire texture to ram at once?  A performance hit would
> be better than dieing for lack of ram.

What good would that do, actually?

POVRay dying from lack of ram usually means not enough physical RAM, leading to
use of virtual RAM and consequently death by swapping. Or, to put it
differently, death by excessive HD access.

Leaving textures on disk would just be choosing a different mechanism to create
a lot of HD traffic.

So I guess loading the texture into memory at the *risk* of starving from
swapping is still better than leaving it on disk and being *sure* of starving
from excessive HD activity...

The only viable option would be to load a low-res version of the texture into
RAM. But then again, you can just as well crunch down the texture in the first
place.


Then again, if you're thinking of deferring loading of the texture until it is
first used - well, it *will* be used some time during render, so you're better
off with POV-Ray dying during parsing already, than waiting for the first time
the texture is actually used, and *then* dying from an out-of-memory condition.

Post a reply to this message

> Hello,
> 
> I wanted to know if anyone had any experience using multiple very large textures
> (> 2GB), and was able too keep povray from running out of memory.  Also, it
> seems like POVRay loads textures to ram on parse - it it possible to keep
> POVRay from loading the entire texture to ram at once?  A performance hit would
> be better than dieing for lack of ram.
> 
> thank you,
> 
> Jacob
> 
> 
The first question is: Do you REALY need such high resolution textures?
Can you do with a smaller resolution? Change from true colours to high 
colours can also help. (it will reduce the file's size by about half)
You may also split your texture file into smaller pieces and only load 
those that you effectively use.

In your case, you probably need to use the 64 bits version, with a 64 
bits OS and a 64 bits CPU and a computer with over 8 Gigs of RAM.

Another way is to use a compressed file format for your textures. If you 
use a BMP, or uncompressed TGA or TIFF, for your texture, changing to 
PNG or JPG can save you some problems, as well as load much faster.


Alain

Post a reply to this message

Thank you both for your comments.  I was able to get the behavior I wanted
(dynamic access of texture off hard disk) by making a few changes in the
source....

JSchloss

Post a reply to this message