Thread Subject: Animation timer

I want to update a figure plot every 30th of a second to
create an animation with accurate update periods. I can't
simply use pause(1/30) because updating the figure takes
time (although less than 1/30 s) and so it would update
slower than I want so I do the following (with some
pseudo-code):

initialise_parameters;
tic
for i = 1 : 1000
  draw_plot;
  text(10,10,int2str(floor(i/30)))
  drawnow
  pause(1/30 - toc)
  tic
  update_parameters;
end

The text shows the seconds updating so that I can see the
update rate.
This works better but it updates slightly too fast by
approximately 4 seconds per minute.

Does anyone know why this is and is there a better way to
create an accurate animation timer?

Peter Bone

>> help timer

I posted a simple example on the File Exchange:
http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=8452&objectType=FILE

Note that the submission references a corresponding News &
Notes Article. This article ended up not being published,
but you should be able to get what you need from the example
code.

- scott

Never mind my last comment - we published the article a year
later than originally planned:

http://www.mathworks.com/company/newsletters/news_notes/oct06/tips.html