Vahur Krouverk wrote:

> Warp wrote:
> >
> >   It would have been interesting if you had provided some benchmark results
> > (eg. how much time does it take to render a shader compared to a regular and
> > similar texture, etc).
> >
> Of course, but I've developed it on 486/DX2 66MHz and this is not just
> best box for benchmarks.
> Now when I have Windows version, I try to perform tests on my working
> machine (PII 350Mhz).
>
> But results of some tests (this was on performed on  Linux with debug
> version):
> Pure shader call (well, almost, it assigned red to surface color)
> increased execution time 33 % (pure POV-Ray executed scene 15 seconds,
> with shader it took time 20 seconds). Main overhead comes from memory
> management (separate shader instance is allocated each time in order to
> be reentrant), if I tried it without allocation, then time was almost
> same (16.xx sec). So there is area for improvement (one possibility it
> to preallocate shader instances).
> When shader has more code, then difference will be bigger: e.g. povshad
> scene, which renders one sphere with POV-Ray shading, other with shader
> language, has following results:
> Pure POV-Ray sphere: 12 seconds
> Shader sphere :      38 seconds
> Here probably illuminance loop, which is executed for shading, incurs
> such an overhead. Alas, this is the price for flexibility.
>
> However, I consider it as beta version and with this release I wanted to
> test, whether there is enough interest for such patch. So far I've tried
> to make it correct, performance has not been my major concern. In future
> I will tinker with performance buttons and knobs more.

Are you kidding? When I discovered that there exists something like POVMan, I
promptlly
went to its homepage. You can't imagine how I was disappointed when noticed there
is
no download available on the page! (Still I was lazy enough to mail the author :-)

I wonder whether the POV-Team consider implementing (any) shading language for the

planned 4.0 release. They say it's going to be a MAJOR rewrite of the POV-Ray
core.
Why not to expand POV's texturing and/or shading capabilities when such an
opportunity comes ?.

Thanks for your time spent on writing POVMan, you make a great job!


Jakub Hegenbart

heg### [at] postcz

Post a reply to this message