[PD] PD GEM Alpha for Two Videos

[Max Neupert]

just a guess:
try changing the order of alpha and colorRGB	


Am 25.02.2006 um 04:18 schrieb Mike Pascarella:

> Hi all,
>
> I'm new to the list, but have been using Pd for a while.  Recently,  
> I have been trying to use GEM to control the opacity of two  
> videos.  I have found some threads in the archive discussing how to  
> set it up, but have run into a strange problem.  If I have only one  
> video active, I can change its opacity.  Once I introduce the  
> second video, I lose the ability to change either video's opacity  
> (actually, they both become 100% opaque).  Here's how I set it up:
>
> Video 1:
>
> gemhead 50
> colorRGB (using a slider to adjust the fourth alpha channel)
> alpha
> pix_film
> pix_texture
> rectangle
>
> Video 2:
>
> gemhead 51
> colorRGB (using a slider to adjust the fourth alpha channel)
> alpha
> pix_film
> pix_texture
> rectangle
>
> I do have a work-around, but I'm baffled as to why it works  
> (obviously, I need to learn more).  If I add the following to my pd  
> document, I can then control the opacity of both videos:
>
> gemhead 50
> square (or any shape)
>
> Since I don't want the new object to be visible, I changed it to  
> the following:
>
> gemhead 50
> colorRGB 1 1 1 0
> alpha
> square
>
> It works, but I don't know why.  Can anyone shed some light on  
> what's going on here?  I'm using Miller's OSX compile 0.39-2 and  
> the latest compiled version of GEM (G4 version).  System is a 1Ghz  
> Ti-Book with 768  Mb RAM running OSX 10.4.3. Thanks.
>
> Mike
>
>
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