[PD] chroma_key to alpha with Gem?

Hans-Christoph Steiner hans at at.or.at
Mon Apr 20 22:09:28 CEST 2009

I haven't written a shader before, anyone have one they could share?   
Or is this possible without shaders, i.e. just Gem objects?


On Apr 20, 2009, at 3:55 PM, chris clepper wrote:

> I have done a lot of this type of processing with a shader.  Just  
> pick the color in the desired range and set the alpha of a pixel in  
> that range to 0.  After that just lay the video on top of each other.
> On Mon, Apr 20, 2009 at 3:34 PM, Hans-Christoph Steiner  
> <hans at at.or.at> wrote:
> I was wondering whether it is possible convert a specific color,  
> like green-screen chroma key, to alpha information using Gem.  They  
> idea is to overlap many green-screen videos.  I can see the pieces,  
> but I can't see the whole.
> .hc
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