[Kde-games-devel] QGraphicsScene performance

[Ian Wadham]

On Sun, 1 Jul 2007 01:32 am, Martin Heni wrote:
> I have followed this discussion a bit and found one remark
> particular true, saying that it is ridicoulous that we can run less
> graphics objects on our 4 GhZ computers than a C64 could... ;-)
>
I'd like to offer a couple of counter-examples, to restore our faith
in our multi-GHz machines ... :-)

I have a Rubik's Cube program I have been working on, based on
Open GL and 3D graphics.  Using only software (my graphics card
is driverless), it can animate a 6x6x6 cube with 216 "cubies", 216
colored "stickers" and numerous bevelled edges.  The animation
rotates the entire cube randomly in space and at the same time
shuffles and solves the cube.  It also calculates perspective,
lighting and color variation of each sticker for each frame of
animation.  This is on a 2.4 GHz machine.  You can see something
similar in the Rubik XScreensaver that comes with KDE3.  Such
graphics was inconceivable on my Apple IIc!

Around the time I bought the Apple, my first home computer,
I was consulting in my daytime job to an Australian Government
department and they were using the world's first windowing
machine, the Xerox Star workstation, complete with Ethernet,
print server and file server.  It was beautiful to use, but painfully
slow, even though it contained one of the most advanced CPUs
of its day.

As a test one day, I clicked on a WYSIWYG word-processing
document, to retrieve it from the file server and open it on the
desktop.  Then I walked along a corridor, down one floor and
along to the File Registry counter, where I requested the clerk
to fetch me a paper copy of the same document.  I received it
and returned to my office ... just in time to see the Star copy of
the document appear on the screen!

In another test, I got one of the department's senior officers to go
through a typical writing and editing session in which he told me
whenever he was stuck with nothing to do but wait for the Star.
This turned out to be about 50% of his time.  In spite of this, he
was still enthusiastic about the Star, preferring it greatly to the
usual process of hand writing material and sending it to the
typing pool, then correcting it and sending it back, etc.

On my 2.4 GHz machine, I can edit and turn pages as fast as
I ever could on paper.  The only thing I miss is not being able to
stick in my fingers, to hold pages open while chasing a chain of
cross-references, though you can do something like that in a
tabbed browser now.

All the best, Ian W.

P.S.  If you find these recollections boring, just tell me to shut
up.  I won't mind.  I just find it useful to have some perspective
on blips in graphics or other performance in today's machines.