Can I ask why this is faster than an equivalent Core Image node? Patrick
On Apr 21, 2012, at 10:55 PM, Achim Breidenbach wrote: > Hi Alastair, > > I definitely would go with a GLS Shader patch if you can't get the > performance with the regular patches. find attached a sample composition. > > best, > > Achim Breidenbach > Boinx Software > > <scrollingTextWithMask.qtz> > > > On 20.04.2012, at 08:19, Alastair Leith wrote: > >> Hi List >> >> I'm trying to make an image mask for a billboard such that the masked area >> stays static while the image of some text moves up and down (as if) inside >> the bounds of a masked window. The problem I am having is that there is no >> simple way to give an absolute position for the mask while moving the image >> independently, like you say a mask in PS or AE behaves. Typically the >> billboard patch scales a rendering-destination-dimension sized mask image >> down to be relative to the size of the input image rather than use it as a >> mask the size of the rendering destination (Problem 1). >> >> If I use an Image Transform Patch to translate the text image up/down on the >> Y-Axis the Billboard patch basically ignores the change in bounds and just >> centres the image at the same origin as determined by X pos, Y pos and image >> size (Problem 2). >> >> I did make a successful composition that creates a mask the same size as >> source image (an Image from String patch output) by 'screen' blending black >> and white cropped images (doing math for the crop inputs to get positioning >> relative white/black correct) then using a Mask to Alpha patch and inputting >> it to the Billboard. By animating several of the cropping offsets and >> heights and the Y-Position of the Billboard I can generate the desired >> animation of text scrolling up and down inside window bounds. Problem with >> this solution is it seems overly complicated, a little CPU hungry on my old >> mac anyhow, and because the crop patch uses integer inputs, an animation >> that only moves the mask say 33 pixels is noticeably jerky (only just) as >> compared to just animating Y Postition of a billboard with cropping sprites >> all around it. >> >> Maybe animating a billboard with cropping sprites set to alpha-0%-black >> (blend mode: replace) on higher layers inside a RII patch is the way to go >> but I'd like to avoid RII patch on principle that's more overhead. I don't >> mind using RII patch to construct the mask if it is static and wont keep >> re-evaluating but that gets me back to Problem 1. >> >> Any assists/demos/thoughts gratefully received. I'm sure some of you have >> been here before — I know I have :-) >> >> Alastair Leith >> >> The machine does not isolate man from the great problems of nature but >> plunges him more deeply into them. >> Antoine de Saint-Exupery >> >> _______________________________________________ >> Do not post admin requests to the list. They will be ignored. >> Quartzcomposer-dev mailing list ([email protected]) >> Help/Unsubscribe/Update your Subscription: >> https://lists.apple.com/mailman/options/quartzcomposer-dev/achim%40boinx.com >> >> This email sent to [email protected] > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Quartzcomposer-dev mailing list ([email protected]) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/quartzcomposer-dev/psheffield%40earthlink.net > > This email sent to [email protected]
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