Dr Andrew C Aitchison wrote:
I thought about using the shadow framebuffer also. It seems like the easiest way. I need to get myself more acquainted with shadow framebuffer. For our new chip I need to specify an overlay surface and an underlay surface, the chip will take care of overlaying both surfaces. That is why I'm asking this. I hope that I'm thinking in the right direction.On Mon, 11 Nov 2002, Luugi Marsan wrote:The current implementation of Overlay for the G450 seem to write the 8bpp image by placing the pixel value at the top byte of each pixel. Then the G450 takes care of doing the overlay by specifying to the card the pixel configuration. If I wanted to have the overlay suface draw on an separate surface, how would I do that?The best solution might require writing support in the server, but here is some other brain-storming:At some level pretend it is a different head. Since it is an overlay X doesn't *have* to know that it is related to the underlay (although it would defeat obscured window optimizations). Use a shadow framebuffer, and blit into the 8bit framebuffer. You can probably do better by drawing directly into the 8bit fb, pretending it is pixmap in video memory, but shadow may be easier.
I don't know much about XV either.XV does overlays; is it useful to use video memory as an XV source ? (I don't know much about XV)
I'll check it out.I think that (some of the) C&T hardware (using the chips driver) have this cabability. I may be confusing it with another manufacturer (S3?) and I don't know whether we ever supported it. This might be productive lead, or it may be a red herring.
Thanks
Luugi
