nanogui: Offscreen Drawing -- tapping offscreen buffer ?
Subject:
Re: [nanogui] Offscreen Drawing -- tapping offscreen buffer ?
From:
Yan Seiner ####@####.####
Date:
18 Nov 2005 13:47:38 +0000
Message-Id: <437DDB71.5070403@seiner.com>
Amareesh Kalra wrote:
> Hi Greg,
>
> What exactly is meant by offscreen drawing ?
>
> My guess was a region in user space which is copied to the
> framebuffer(mmap'd).
>
> We are attempting to 'tap' this offscreen buffer and send it to the
> dsp for rendering as our host board does not have a display card.
>
> On going thru the code briefly, we found this offscreen buffer is not
> 'filled'(probbly abstracted by the X library calls). Straight away the
> framebuffer is filled with display data.
>
> Any insight on this issue is welcome.
I had a similar need - I wanted to use the kernel fbdev driver as a
virtual frame buffer for nano-X, so I could run vnc on an ARM platform
with no video hardware.
See my query for 'virtual frame buffer' on the linux-fbdev-users list
at http://linux-fbdev.sourceforge.net/
I spent about an hour looking at the changes that would be required to
the kernel driver, and realized that there is a reason why I'm not a
kernel hacker... :-)
Seriously, it doesn't seem like a lot of work for someone who
understands kernel drivers, but it would be a serious effort for me.
But if anyone is interested in working on it, I would be willing to
contribute my updated nano-X code with a working vnc server. (I haven't
released it because it is mostly working; I've got the session-start
stuff bollixed up. You have to start a vnc client, then connect via a
browser to port 5800, then the authentication window for the vnc client
pops up.... It works for me - I start it once and leave it running for
a week or more - but not quite ready for the masses.)
OTOH, if anyone needs VNC server capabilities and wants to do some work
to finish it please let me know.
