Thank you for the patch Cyrille. It's a very nice solution.
The only disadvantage is that it makes the background image feedback dependent.
My goal is to isolate the feedback from other geos & image/videos.
So, I was thinking that in order to keep the blur I have to keep the gemframebuffer RGB format and add transparency after it.
I just realized that [alpha] has several blending functions, some of them turn the whole framebuffer transparent.
This is fine but now the geo and blur are also affected (see attached).
I don't know if it is possible to add other type of blending after the framebuffer, maybe sending it to another gemframebuffer and changing the background color (black) to alpha?
I saw that pix_alpha achieve this but I don't know how to use it only with the framebuffer image. Any suggestion is welcomed :)
regards,
andre