[PD] [Gem] how to optimize alphablending?

Alexandre Quessy listes at sourcelibre.com
Sun Aug 28 18:40:00 CEST 2005

I am working on exactly the same thing ! So....

First of all, there should be a way not to load every image twice (once 
in each [pix_multiimage]). This could be done by splitting the list of 
images in 2. But then, we would loose the order, and would need an even 
number of images if we want to keep the order of the pictures on every 
time we go around the whole set of pictures.

My Pd uses 325 Mib of RAM when I run this.

Another thing to consider : my digital camera generates pictures with 
names such as "IMG_0792.JPG". I know that [pix_multiimage] needs a 
directory of pictures with sequential numbers, but can skip some. Is 
there a turn around if we dont have sequential numbers ? I am working 
on a way to get a file list with a [pyext] script, and to put that list 
in a [pool] or something. But my filename numbers aren't sequential, 

I'll post this slideshow patch/script if I get it done. :-)


Le 05-08-28, à 11:47, Roman Haefeli a écrit :

> hi
> i attached a patch, that is used to 'alphablend' from one to another
> picture. it is working though, but the cpu-load raises to 100% and it
> looks quite 'ruckelig' (not constantly flowing). i tried it on 
> different
> machines with the same result. then i tried it with a better gfx-card,
> that supports opengl (Quadro FX 330), on a P4 2.66GHz (winxp). it looks
> better, but my patch still uses 100% cpu.
> i'm quite a gem-newbie and don't know much about opengl, but i assume
> that my patch is not optimized and there is still much calculated by 
> cpu
> instead of gpu. last week i saw a screensaver-slideshow on an old 
> ibook,
> that looked very nice. this let me hope there is still a chance, that i
> can realize the same with Gem on hardware that is up-to-date.
> thanks for any help
> roman
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