yah...i just bought ''Advanced animation with DirectX'', and i have a question about chapter 13''s cloth demo. When i move the window, the cape goes crazy. I''ve yet to read the chapter :D, but i''m curious if it is supposed to do this, or not.

yes, i realize this, however, if move the window, the cape gets extremely long and weird. The same thing happens with the softbody demo. If i move the window right before she lands the punch, her boobs go crazy (crazier than it is supposed to be). does it do the same on your computer?

Well for book demos, they try to keep it to relevant code as much as possible, so they didnt put in code to handle all the possible things that could happen with the operating system (moving/resizing/minimizing/maximizing/alt-tabing). I dont own the book so i never looked at the samples, but it how nearly all the samples from other books work, they become unstable if you try to do more then just open and run them nicely. I wouldnt worry about it. It does work when you dont move the window around, right? Just make sure to handle the windows events properly when you write your own game, the book techniques are still valid.