I am at loss once again. I have the latest Ubuntu Dapper Drake and I'm using its nVidia (binary) drivers with hardware acceleration ("nvidia", not "nv"). I have xscreensaver installed (not gnome-screensaver) and electricsheep screensaver (both of them from standard Ubuntu repositories).
Unfortunately, when electricsheep starts, it runs (e.g. it downloads new sheep generations) but does not produce any graphical output at all! The screen is black. The preview window in xscreensaver-demo is black. When I run electricsheep manually in a window, the windows decorations appear (the border and the toolbar) but the window itself is "see-through" (not black), the content is simply not there.
Another interesting observation: When I have mplayer running (it doesn't matter if it's paused and on which workspace it runs, but it must use hardware acceleration), electricsheep works like a charm - standalone or in the preview window! Also, when I reboot the computer (or just the xorg server), electricsheep WORKS but it stops working as soon as I close the MPlayer for the first time.
All other screensavers (3D or not) work without problems. When I change the video driver to non-accelerated one ("nv"), electricsheep also works without problems.
Any ideas? Some nvidia driver flags I could tweak? Or Mplayer? It doesn't seem to matter what Mplayer video driver I use...