[PD] chroma_key to alpha with Gem?
cyrille henry
cyrille.henry at la-kitchen.fr
Mon Apr 20 23:39:59 CEST 2009
Hans-Christoph Steiner a écrit :
>
> I haven't written a shader before, anyone have one they could share?
yes, there are some in the Gem examples.
example/10.glsl directory
> Or
> is this possible without shaders, i.e. just Gem objects?
pix_alpha does it, but it's very basic.
pix_coloralpha can do it with other pix_objects.
Cyrille
>
> .hc
>
> 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
>> <mailto: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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