17 Mar 1994.
Dear PC POV users,

I have compiled POV-Ray 2.2 for the PC using Watcom386 and full optimisations.
Please note that it is a 486DX-optimised AND PENTIUM-optimised version (386DX's
should still run but ONLY when equipped with a coprocessor). YOU WILL NEED A MATH 
COPROCESSOR (or a processor which includes one) TO RUN THIS VERSION.
This one presents identical performance for 486/386 ' s as the povfast2 version
but should be much faster on a PENTIUM machine.

It is available via anonymous ftp on:
	 dolphin.doc.ic.ac.uk:/pub/graphics/pov-dos/povfast21.zip

You will need the dos4gw.exe Rational Systems dos extender run time module 
in your path (I include it - it is the same extender distributed with 
ghostscript for dos).

The new executable presents (compared to orig distrib in alfred.ccs.carleton..):
a speedup as follows:
- On DOS 5.0 486DX/25,386DX40/copro - 4MB: speedup of 12-25% on most scene files
- On DOS 6.2 486DX2/50 - 12MB: about 10x speedup! This indicates that there
  must be something wrong with the ICB extender running under DOS 6.2: POV was
  running extremely slow on my home machine which is what forced me to try a
  recompilation with watcom's 386 compiler.

You might find that for some (old) cards the display autodetect does NOT
work. Use +d?? (specify ?? explicitly according to IBMPC POV documentation,
file IBMPC.DOC, also included) and it should work without a problem
(eg: +d1 for vga).

Feel free to re-distribute it according to the conditions set out in the
file POVLEGAL.DOC (also included). 

Please, send me an e-mail if you find POVFAST faster on your PC. Tell me
if you also noticed the slowness problem with dos 6.2.


!!!!!!!!!!!!!!!!!!!!!!!!!!!!! IMPORTANT !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
NOTE: THIS IS AN UNOFFICIAL DISTRIBUTION.  The OFFICIAL ONE CAN BE FTP'ed
FROM alfred.ccs.carleton.ca:/pub/pov-ray. DO NOT REPORT PROBLEMS OF THIS
EXECUTABLE TO THE ORIGINAL AUTHORS !!!
I MAY OFFER VERY LIMITED SUPPORT ON THIS VERSION AND ONLY VIA E-MAIL.
NO WARRANTIES WHATSOEVER.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

NOTE:
There have been long discussions about 'correctness' of different compilations
of POV. You WILL find differences in files rendered with this version
and the ones rendered by the original executable. I found this to be the case
only on files which depend on use of the rand() library function (random noise
textures etc use it). These differences are due to differences in the rand()
function itself in various compilers. I do not know whether ANSI defines a
standard for the rand and srand functions semantics - I am also not sure
whether the copies of these functions provided in IBM.C source file are the
'standard' ones - feel free to comment on this and if you know which is the
standard, if any, I can incorporate on a later compile. I think the best
way to avoid this problem for good is to override the library rand() generator
and use a custom one (eg pov_rand() and pov_srand()- there is plenty of code
available).

Enjoy (faster) POving...,

---
 Angelo Haritsis, Applied Systems Section
 s-mail: Dpt of Computing,Imperial College, 180 Queen's Gate, London SW7 2BZ, UK
 e-mail: ah@doc.ic.ac.uk - tel:+44 71 225 8452 - fax:+44 71 589 7127