Consistently use meta_grab_op_is_resizing() for _NET_WM_SYNC_REQUEST
In different places we checked the grab op differently when determing
whether we are using _NET_WM_SYNC_REQUEST. This was somewhat covered
up previously by the fact that we only had a sync alarm when using
_NET_WM_SYNC_REQUEST, but that is no longer the case, so consistently
use meta_grab_op_is_resizing() everywhere.
Distinguish "no delay" frames from spontaneous drawing
When a client is drawing as hard as possible (without sleeping
between frames) we need to draw as soon possible, since sleeping
will decrease the effective frame rate shown to the user, and
can also result in the system never kicking out of power-saving
mode because it doesn't look fully utilized.
Use the amount the client increments the counter value by when
ending the frame to distinguish these cases:
- Increment by 1: a no-delay frame
- Increment by more than 1: a non-urgent frame, handle normally
We previously had timestamp information stubbed out in
_NET_WM_FRAME_DRAWN. Instead of this, add a high-resolution timestamp
in _NET_WM_FRAME_DRAWN then send a _NET_WM_FRAME_TIMINGS message
after when we have complete frame timing information, representing
the "presentation time" of the frame as an offset from the timestamp
in _NET_WM_FRAME_DRAWN.
To provide maximum space in the messages,_NET_WM_FRAME_DRAWN and
_NET_WM_FRAME_TIMINGS are not done as WM_PROTOCOLS messages but
have their own message types.
Add a function to convert from g_get_monotonic_time() to a
"high-resolution server timestamp" with microsecond precision.
These timestamps will be used when communicating frame timing
information to the client.
Use XSyncSetPriority() to prioritize the compositor above applications
for X server priority. In practice, this makes little difference because
the Xorg "smart scheduler" will schedule in a single application for
time slices that exceed the frame drawing time, but it's theoretically
right and might make a difference if the X server scheduler is improved.
Using a "sync delay" where we wait for 2 ms after the vblank before
starting to draw the next frame provides for much more predictable
latency for applications. An application can know that if it completes
a frame any time between 8ms before the vblank to the vblank,
it will reliably be drawn on the following vblank period, rather than
having an unpredictable latency depending on whether the compositor
is currently busy drawing a frame or not.
Instead of defining CLUTTER_ENABLE_EXPERIMENTAL_API and
COGL_ENABLE_EXPERIMENTAL_API in individual source files, enable
them on the command line. We weren't tracking exactly what pieces of
experimental API we were using and we were using the experimental
API in most source files that used Clutter and Cogl, so the
local #defines were annoying rather than useful.
Handle _NET_WM_SYNC_REQUEST_COUNTER updates without redraw
It's possible that a client might update the (extended)
_NET_WM_SYNC_REQUEST_COUNTER counter twice without actually drawing
anything. In that case, we still should send a _NET_WM_FRAME_DRAWN
message since it's hard for a client to know every case in which
no damage is generated. For now, do it the easy way by forcing a
stage repaint.
MetaWindow: always resize the frame first when we have synchronization
Resizing the frame triggers creation of a new backing pixmap for the
window, so we should do that first before we resize the client window
and mess up the contents of the old backing pixmap.
When the application provides the extended second counter for
_NET_WM_SYNC_REQUEST, send a client message with completion
information after the next redraw after each counter update
by the application.
