Your composition and result does make sense while it's running, and is what I would expect.
I guess what is still "weird" to me, is how I can coax 2 rendered objects out of this setup at two iterations, but only if I manually commit, and choose one iteration first. In your composition, if I stop it at two iterations, the placement of the iterations shifts from bottom, and top right corner, to both at top after a few seconds. Everything considered, I can't understand why the state of the composition would shift like that, when all value are consistent. So, I do understand what you are conveying about this generally being not_a_good_idea, and the reasons why. However, the random shifting (in render count or placement) still seems flaky even considering your points, and like placement/rendering should lock in one way or another (thankfully, I've not been bitten by thinking this worked predictably). Thanks for your thoughts, as always, -George Toledo On Fri, Jul 2, 2010 at 4:44 PM, Christopher Wright < christopher_wri...@apple.com> wrote: > > The reason I seek inquiry on this; am I misunderstanding what a square > wave should render in this scenario? I believe that it should render two > Sprites. In any event, it doesn't seem like this should ever be dependent on > the Editor state in this way. > > You _really_ don't want to abuse square wave and patch time like this; > floating point math isn't exact, so subtle rounding errors can make edge > cases pass or fail contrary to what you expect. That's not at play here, > but in general this is dodgy territory. > > With 1 iteration, Iterator Variables' position is always 0.5. With 2 > iterations, position will be 0 and 1. With 3, it will be 0, 0.5, 1. > > A square wave from LFO with a period of 1 will have an output of 1 at 0 and > 1 (but not 0.999). In fact, with a period of 1, _all_ integer times will > output 1 (until rounding kicks in at larger times). It remains 1 for the > first half of the phase [0-0.5), and 0 for the second half [0.5-1.0) -- note > the braces, they're important ( > http://en.wikipedia.org/wiki/Bracket_(mathematics)#Intervals ) > > Anyway, I used your composition as a skeleton, and fleshed it out to graph > LFO operations over an iteration interval (plotting X and Y as Iteration > Position and LFO output respectively), and don't see anything unusual -- > just the LFO outputting 1 at both 0 and 1, which could seem unusual but is > in fact mathematically sound. > > > > -- > Christopher Wright > christopher_wri...@apple.com > > > > >
_______________________________________________ Do not post admin requests to the list. They will be ignored. Quartzcomposer-dev mailing list (Quartzcomposer-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/quartzcomposer-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
