hi,
Mark Vojkovich [EMAIL PROTECTED] wrote on Wed, 16 May 2001 11:32:20 -0700 (PDT)
> On Wed, 16 May 2001, Peter Ronnquist wrote:
>
> > Hello,
> >
> > I am trying to figure out how to update the screen
> > during vertical retrace. Is this possible with Xfree?
>
> No. Not in any portable way. Only if the client knows
> hardware specifics and runs as root and pokes registers.
>
> If you are using OpenGL, your OpenGL implementation may
> be able to do buffer swaps synced to the retrace. Probably
> not though.
>
> Mark.
Sorry to quote a quite old posting.
Just a short question related to the topic above:
Isn't the following fairly portable without OpenGL (at least to
architectures where DGA2 is available)?
[ From README.DGA ]:
void XDGASetViewport(
Display *dpy,
int screen,
int x,
int y,
int flags
);
[...]
viewportFlags
Any of the following may be OR'd together:
XDGAFlipRetrace
Indicates that the hardware can switch viewports during
the vertical retrace.
XDGAFlipImmediate
Indicates that the hardware can switch viewports immediately
without waiting for the vertical retrace.
[...]
I'm using this to get smooth animations with DGA2, and to some extent
it works. As it's not perfect (probably my fault) I'm still interested
in this topic.
thanx,
martin
PS: please CC to my address above, as I'm not subscribed to the Xpert
list. Thanx.
_______________________________________________
Xpert mailing list
[EMAIL PROTECTED]
http://XFree86.Org/mailman/listinfo/xpert
