[PD] Fading out of buffers

[Florian Grond]

Hallo,

I'm new in the list so please apology if I do not meet yet the netiqette
rules etc.
I would like to render images in a gem window and than to fade them out
by multiplying the framebuffer by a number smaller that 1.
than further images should be rendered and fade out again, and so on.

Can anybody help me please, where to find the necessary information how
to manipulate buffers in gem for the purpose described above.

Thanks a lot,

Florian