nanogui: screen subdriver problems
Subject:
Re: [nanogui] Re: screen subdriver problems
From:
"Greg Haerr" ####@####.####
Date:
23 Aug 2005 19:02:39 +0100
Message-Id: <04ad01c5a806$a65dea50$6401a8c0@winXP>
: My advice is to add a sync hook to the driver structure. Of course, most
of
: the drivers won't have a need for a sync function, so no drastic changes
would
: be needed in the driver/ directory, as we could just leave those null.
:
: Then, we should define a macro like so:
:
: #define NXSYNC(psd) \
: do { if ((psd)->Sync != NULL) psd->Sync(); } while(0)
I agree that for cases where there's no direct access to video memory,
a Sync driver entry point would be a good thing. However,
think it should also have x,y,w,h values passed to allow optimal
update of the display. This would be the same design SDL
uses, which works quite well.
: Anyway, the point is that the NXSYNC() macro should then go at the bottom
of
: any drawing functions to flush the hardware as needed. I think the
process
: of adding NXSYNC() calls can be organic (in that we add them as we need
: them), unless anybody has the initative to add them everywhere at once.
Generally agreed. However, since Microwindows already
completely handles framebuffer, another approach would be to
use a generic "sync" driver, where all data is written to local
RAM, and then synced using a subdriver to actually move data
to the external display. In this way, the syncing would only have
to be done once, before the processor select() function, and the
"sync rectangles" could be aggregated so that only one update
is required.
Regards,
Greg
