Why is this so slow? (Optimization help)

Hey, guys (and I use guys in the genderless 'yo, DUDES' kinda way)

I've got this filter Cityscape (submitted, but not up yet) that is slow as snot to render. Now, it uses 5 noise gradients to generate the buildings. I know they are slow, but it seems like this is very, very slow.

The 'slow' components in the filter:
5 noise gradients,
1 blur,
1 refraction

I think that is it regarding slow components. Everything else is just blend, blend, blend and other things that are listed as 'fast' stuff.

Any speed hints? (or hints in general. I love this filter, but that might just be me.)

Cityscape.ffxml

Quote
ronviers wrote: I think this filter is just going to be slow

Yeah, sometimes it's unavoidable. I would suggest simplifying as much as possible before refraction.....which I'm finding to be the "problem child" of components.....

Wow. That's cool. I could totally do that... didn't even occur to me.

The refraction is WAY over to the side... and now that I think about it, it's a noise distortion, not a refraction. ::

uberzev's like some kind of mythical being of wisdom and filterknowlage.

Carl,

The version that just got accepted is the 'first' version...a better version will be coming at some point soon.

Hm. Well, this doesn't work well on 'portrait' style images anyway (if you knock the size down, it just makes horizontal rows of cities,) so I'd be interested in a better way if you've got one.

Other than the fact that profile gradients break on non square images, are there other reasons NOT to use them? For some reason I got it into my head to avoid them... I think perhaps because of the non-square thing, but I'm not positive.