David Olofson wrote:> On Wednesday 13 March 2002 21:47, Jason Hoffoss wrote:
There will be retrace sync and pageflipping on all properly
supported video cards on Linux eventually, if I can help it. I
frankly don’t care if some people consider tearing and jittering
acceptable. I do not, and I intend to figure out a way to fix it,
unless someone beats me to it.
Cheer
So are you joining the Xfree86 project then? 
Or do you have other
ideas for doing this?
Well, it depends on how things turn out, but I’d guess the scale of it is
more in the order of a some contributed code. The only issue that might
require deep hacks in XFree86 is the actual pageflipping. The other stuff
should be fairly trivial, possibly except for testing for retrace on SMP
machines with some video cards…
Well, I built my first page flipping X server in about 1987… X servers
for high performace graphics machines was how I made my living from
about '87 thru '92. The problem areas are how to synchronize multiple
flipping windows and how to keep the non-synched part of the screen up
to date. Some video systems have video select planes that control the
physical layout and the pixel plane to display. Most don’t. If you’re
lucky you can get take over the clipping planes to help. On most systems
though you have to have the server render all non-flipped stuff into all
planes so it is visible after a flip. There are also a few problems with
sharing the graphics pipe state between multiple windows and keeping the
Z buffer clean is a real pita.
Or, were you just going to ask the X server to get out of the way and
let you have direct access to the hardware and the rendering pipe? Isn’t
that called DRI?
Bob Pendleton
David Olofson wrote:
There will be retrace sync and pageflipping on all properly
supported video cards on Linux eventually, if I can help it. I
frankly don’t care if some people consider tearing and jittering
acceptable. I do not, and I intend to figure out a way to fix it,
unless someone beats me to it.
Cheer
So are you joining the Xfree86 project then? Or do you have other
ideas for doing this?
Well, it depends on how things turn out, but I’d guess the scale of
it is more in the order of a some contributed code. The only issue
that might require deep hacks in XFree86 is the actual pageflipping.
The other stuff should be fairly trivial, possibly except for testing
for retrace on SMP machines with some video cards…
Well, I built my first page flipping X server in about 1987… X
servers for high performace graphics machines was how I made my living
from about '87 thru '92. The problem areas are how to synchronize
multiple flipping windows and how to keep the non-synched part of the
screen up to date.
Yes, I’m perfectly aware of that - but right now, I’m only interested in
fullscreen modes.
Still, it would be kind of cool if XFree86 could do it in windowed mode
as well. It would be one of very few (if any) targets available to
"normal" users to do that…
Some video systems have video select planes that
control the physical layout and the pixel plane to display. Most don’t.
If you’re lucky you can get take over the clipping planes to help. On
most systems though you have to have the server render all non-flipped
stuff into all planes so it is visible after a flip. There are also a
few problems with sharing the graphics pipe state between multiple
windows and keeping the Z buffer clean is a real pita.
I’d say it’s messy enough to do it within a fullscreen pageflipping
application, so I can definitely see the problems here.
Or, were you just going to ask the X server to get out of the way and
let you have direct access to the hardware and the rendering pipe?
Isn’t that called DRI?
Basically, yes. DRI (for OpenGL) and fullscreen DGA. (I’m not going to
fork XFree86 and rewrite half of it myself. I’m no that insane! I
think…
//David Olofson — Programmer, Reologica Instruments AB
.- M A I A -------------------------------------------------.
| Multimedia Application Integration Architecture |
| A Free/Open Source Plugin API for Professional Multimedia |
----------------------------> http://www.linuxdj.com/maia -' .- David Olofson -------------------------------------------. | Audio Hacker - Open Source Advocate - Singer - Songwriter |-------------------------------------> http://olofson.net -'On Thursday 14 March 2002 00:54, Bob Pendleton wrote:
On Wednesday 13 March 2002 21:47, Jason Hoffoss wrote: