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>
> Nathan Kopp <Nat### [at] kopp com> wrote:
> : A portable version of these operations could be written, using logrithms and
> : fractional powers, but it would be significantly slower. I suggest #ifdef
> : blocks so that VAX and other non-IEEE-compliant systems will be able to run
> : this code, even if it does have to run slowly.
>
> I definitely agree. Optimizations are ok, but there should always be the
> possibility of compiling it in any system.
>
I agree also...
Currently, here's the situation...
OpenVMS on Alpha platforms does have IEEE float mode (using the compiler
switch
"/FLOAT=IEEE_FLOAT") and using that without the modifications to
"octree.c"
allows radiosity to work just fine.
OpenVMS on VAX platforms don't have a IEEE float mode so I have to use
the
modifications for "octree.c" to make radiosity work.
What I've done is put in an "#ifdef" for OpenVMS VAX in "octree.c" so
that
only OpenVMS VAX will use that modification.
I did some testing between using IEEE float and the modification in
"octree.c"
on the Alpha plat form and this is what I found.
Using the "RAD2.POV" radiosity file and using the following POV
command...
povray +IRAD2.POV +ORAD2.TGA +FT +Q9 +QR +V1 +D +A0.300 +W640 +H480
+B1000
using the modified "octree.c" and not using IEEE float it took 7
minutes, 54 seconds. Using IEEE float and not useing the modified
"octree.c" it took
4 minutes, 47 seconds, a definate improvement. (Note the Alpha platform
was a AlphaStation 500/333, a 333MHz system).
--
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