From: Bill Kelly <billk@...>
Date: 2003-04-09T17:16:30+09:00
Subject: Re: [Q] Ruby for graphics

Hi,

From: "Bil Kleb" <William.L.Kleb@NASA.Gov>
>
> Bill Kelly wrote:
> >
> > In addition to all my other uses for Ruby, I do actually use Ruby to
> > prototype graphics algorithms: precisely because Ruby is such a high-
> > level, powerful language.  But I do expect to re-code the finished
> > algorithms in C++ for speed.
> 
> After measuring the bottlenecks and only corrected those as necessary?
> Or a complete re-write?

I think I probably spoke a bit over-generally, based on my project-
of-the-moment.  I'm a huge fan of measuring before optimizing, and 
I've been (indeed) doing some rough C++ timing estimates while coding
the Ruby sample implementation of what are intended to be some very
real-time pixel filtering operations.

In Ruby it was convenient for me to develop the filter in an object-
oriented manner... but now that I understand how the filter works,
it boils down to a few memory fetches, some arithmetic, and a few
memory stores per pixel.  I *could* optimize the Ruby version a bit,
of course - now that I know how to actually code the thing. . . 
My current Ruby implementation gets less than one frame per second on
a 120x144 buffer, whereas my rough C++ timing tests indicate I should
achieve a few thousand frames a second on that sized buffer in that 
language. . . . But my Ruby implementation was never intended
to *be* fast... I used Ruby to explore an idea and learn how to
achieve the filtering effect I desired...

So in essence I guess I've selected about the most inappropriate
task for which to use Ruby from a speed perspective - but I knew that
going into it... The whole filter *is* the bottleneck.  :)  But I
still found Ruby very useful in developing it.


Regards,

Bill