VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Wed Feb 28 2007 - 00:00:22 CST

Christian,
  The CAVE display mode of VMD has a few limitations which are the
result of limitations in the CAVElib implementation itself. One of
these is that the CAVEDisplayDevice class doesn't process keypress
events except for the ESC key. The reason for this is that unlike
a normal windowing system, CAVElib doesn't provide a function you
can call to get the keypress status of the whole keyboard at once,
nor incoming keypress events. Instead, they only provide a routine
which can check the "on"/"off" status of a single key at a time, with
the CAVEgetbutton() function. This isn't practical for VMD to use
since the keypress state would have to be checked for every single key
on the whole keyboard, including the modifier keys. You can imagine
that running a loop and checking the key state individually for
all of the keys on the keyboard would likely ruin the interactive
display performance since this would occur in the sequential part
of the display code (e.g. the part that's the display rate limiting
sequence of operations). If you want to add keypress checking for
use in your CAVE, it's quite simple, but I hope you have a very fast
machine since it will otherwise negatively impact rendering speed.
If you want to try some experiments to see how bad the performance hit
for scanning the state of the whole keyboard is, I can help you
add the necessary code to CAVEDisplayDevice.

  John

On Tue, Feb 27, 2007 at 12:46:38PM +0100, Christian Wohlschlager wrote:
> ** Reply Requested When Convenient **
>
> Hello !
>
> Unfortunatly the tcl Command : user add key command doesnt work with
> the cavelib , has anyone an idea wy or what i do wrong on out desktop
> its working perfektly ?
>
> ( I' working on vmd 1.8.5)
> thank you
>
> christian 

-- 
NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
Email: johns_at_ks.uiuc.edu                 Phone: 217-244-3349
  WWW: http://www.ks.uiuc.edu/~johns/      Fax: 217-244-6078