Daniel Jungmann wrote:
> 
> 3D!Now and other features make PovRay realy faster ( 50%++, but more then
> 200% is possible) and I said that you should choise ( in the programm
> itselfs, at runtime ) to use fast single precision or slow double precision.
> Every new AMD & Intel processor supports SIMD instructions ( SIMD = single
> instruction multible data, e. g. 3D!Now or SSE ) and if the processor
> doesn't supports this you must not use them. For example if you have an
> Pentium II which doesn't have 3D!Now or SSE then the programm ( PovRay )
> don't let you render the scene with single precision. I know this looks like
> a lot of work, but I don't think so. I did not need 30h to convert most of
> the colour calculation of PovRay from "normal" to 3D!Now. I would do the
> "fast" version for 3D!Now, 3D!NowEx, SSE and SSE2 alone, that is no problem
> for me. And the support is no OS problem, just the processor must support
> the instruction and if it doesn't you can always render with double
> precision. I hope you can understand, because my english is not so good.

No problem with the english, but remember that Povray is not only used on
x86 machines, but also on Mac, Amiga, Sparc, Alpha, ... just to mention
some.  It's a main goal of the Pov-Team to maintain usability for
different platforms which right now is supported through portable c code.
So even if 3D!Now & co were supported by all PC C-Compilers (most
important gcc) this would not be enough.  

Of course you could add a whole lot of '#ifdef' to avoid such problems,
but that would be quite difficult to modify the code, becuase it would
essentially mean two code bases in some parts.  

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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