[PD] [GEM] Flatten Alpha for storage, then restore it

Spencer Russell spencer.f.russell at gmail.com
Sat Aug 2 02:47:36 CEST 2008

The stopgap solution I'm using now is to record the raw output of
pix_background(with the background set to black) and then when I
restore it I'm using an abstraction that uses the image as its own
alpha mask with [pix_takealpha] (the mask image is run through a
pix_gain with a gain of 5 to saturate the mask so it's basically black
and white. (is there a cleaner way to turn all non-black pixels


On Fri, Aug 1, 2008 at 8:25 PM, Spencer Russell
<spencer.f.russell at gmail.com> wrote:
> I'm mixing video by background subtracting it and then setting the
> background transparent (alpha = 0), then texturing each video onto
> overlapping rectangles to achieve a compositing effect.
> I need to record the different videos with [pix_record] and then play
> them back later while preserving the alpha somehow, so I was thinking
> that I could just replace all the transparent part with bright pink or
> something and store it as regular photo jpeg frames, and then later
> set all the bright pink parts to transparent when I read the video
> back.
> I'm having trouble with both sides of the conversion, though. Perhaps
> there's a better approach entirely?
> thanks,
> spencer

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