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Object Rubberband Selection Box

Hi Folks,

The other day someone complained to me in an e-mail that
their rubberband selection box in an object graphics program was
v-e-r-y slow to render. Did I have any ideas?

Since I vaguely remembered doing this before, a long time
ago, and since I didn't recall any particular problems with
it, I decided to look into it. I modified my direct graphics
ZIMAGE program to use object graphics rather than direct
graphics. Guess what? It was p-a-i-n-f-u-l-l-y slow to

Humm. What is going on here!? I was instancing my scene.
I was using a Polyline object for the box. Surely all of
that was right...

After futzing around for an hour or so I decided to
check my rendering setting. Hardware acceleration.
Oh, oh. That should work. Let's try software rendering
just for laughs. Yikes! Rendering was well over 2 orders
of magnitude FASTER! In fact, the damn thing worked now. 

I checked with the folks at RSI (luckily) before I chucked
my graphics accelerator card out the window, and they tell
me that IDL's software renderer has been optimized for 
object instancing. I'm still dubious, but the results
are irrefutable in this instance. :-)

Anyhow, I thought that was worth knowing and it made me
feel like I had gotten *something* done today, anyway.

You can find the program I wrote here, if you are interested:




David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155