Difference Feedback Jitter Problem

CarlR's picture

Hi I have been noodling around with some feedback stuff and have a patch that draws with a sprite. I really like the pattern interference that this creates when the sprite is animated. Problem is that the differencing makes it go crazy. Apologies if this is a basic programming mistake. It is very unlikely I have found a bug. Anyway have a look at the patch, it is a mock up to show the problem. Hope this is fixable because I really like the textures you get when the sprite moves around the screen. The bad effect happens with all image types and movies. At one point the patch was stable until you either moved the sprite OR moved any object in the editor! Just checked on three different macs and is the same.

Any illumination much appreciated!

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DiferenceFeedback.qtz27.58 KB

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CarlR's picture
Re: Difference Feedback Jitter Problem

Here is a png of a screen grab showing the kinds of textures I am getting with this technique

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texture.png
texture.png3.01 MB

toneburst's picture
Re: Difference Feedback Jitter Problem

That's the way difference blending works. It will flip positive/negative each frame in a feedback loop. It's not a bug, just the way the compositing mode works.

a|x

CarlR's picture
Re: Difference Feedback Jitter Problem

Ahhh thanks I suspected something like that. I wish I could make it so that you only see what has been drawn, like if the sprite were invisible but you could still see the background. I can put a copy of the sprite over it but then lose the differencing of the sprite that draws so just its just not the same.

So how could I make my sprite invisible (non-visible?) but still be able to draw?

Video input is great check out this screen grab of a guitar exploding.....

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videodemo.png
videodemo.png2.69 MB