The commit 1c69c61745 which improved the
protection against timeline removals during the master clock advancement
was only doing half the job - and actually broke the chaining of
animations inside the ::completed signal.
We cannot simply take a reference on the timelines and still use the list
held by the master clock because the do_tick() might result in the
creation of a new timeline, which gets added at the end of the list with
no reference increase and thus gets disposed at the end of the iteration.
We also cannot steal the master clock timelines list because a timeline
might be removed as the direct result of do_tick() and remove_timeline()
would not find the timeline, failing and leaving a dangling pointer
behind.
For this reason we copy the list of timelines out of the one that the
Master Clock holds, take a reference on each timeline, advance them all,
release the reference and free the list.
Use the newly-added profiling timers inside the master clock dispatch
function to see how much time we spend:
• in the whole function
• in the event processing for each stage
• in the timeline advancement
A timeline advancement might cause another timeline to be
destroyed, which will likely lead to a segmentation fault.
Before advancing the timelines we should take a reference
on them - just like we do for the stages before doing
event processing. This will prevent dispose() from running
until the end of the advancement.
http://bugzilla.openedhand.com/show_bug.cgi?id=1854
Added an internal clutter function, _clutter_master_clock_ensure_next_iteration
that ensures another iteration of the master clock, can be called from repaint
functions as well as other threads.
A flag in the master clock is now set whenever the dispatch caused an
actual redraw of a stage. If this flag is not set during the prepare
and check functions then it will resort to limiting the redraw
attempts to the default frame rate as if vblank syncing was
disabled. Otherwise if a timeline is running that does not cause the
scene to change then it would busy-wait with 100% CPU until the next
frame.
This fix was suggested by Owen Taylor in:
http://bugzilla.openedhand.com/show_bug.cgi?id=1637
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
Instead of calculating a delta in the master clock, and passing that
into each timeline, make each timeline individually responsible for
remembering the last time and computing the delta.
This:
- Fixes a problem where we could spin infinitely processing
timeline-only frames with < 1msec differences.
- Makes timelines consistently start timing on the first frame;
instead of doing different things for the first started timeline
and other timelines.
- Improves accuracy of elapsed time computations by avoiding
accumulating microsecond => millisecond truncation errors.
http://bugzilla.openedhand.com/show_bug.cgi?id=1637
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
clutter-master-clock.c clutter-master-clock.h: When the
SYNC_TO_VBLANK feature is not available, wait for 1/frame_rate
seconds since the start of the last frame before drawing the next
frame. Add _clutter_master_clock_start_running() to abstract
the usage of g_main_context_wakeup()
clutter-stage.c: Add _clutter_master_clock_start_running()
clutter-main.c: Update docs for clutter_set_default_frame_rate()
clutter_get_default_frame_rate() to no longer talk about timeline
frame rates.
test-text-perf.c test-text.c: Set a frame rate of 1000fps so that
frame-rate limiting doesn't affect the result.
http://bugzilla.openedhand.com/show_bug.cgi?id=1637
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
Instead of trying to guess about which motion events are
extraneous, queue up all events until we process a frame.
This allows us to look ahead and reliably compress consecutive
sequence of motion events.
clutter-main.c: Feed received events to the stage for queueing.
Remove old compression code. Remove clutter_get_motion_events_frequency()
clutter_set_motion_events_frequency()
clutter-stage.c: Keep a queue of pending events.
clutter-master-clock.c: Add processng of queued events to the
clock source dispatch function.
http://bugzilla.openedhand.com/show_bug.cgi?id=1637
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
When a redraw is queued on a stage, simply set a flag; then in
the check/prepare functions of the master clock source, check
for stages that need redrawing.
This avoids the complexity of having multiple competing sources
at the same priority and makes the update ordering more reliable and
understandable.
http://bugzilla.openedhand.com/show_bug.cgi?id=1637
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
If a timeline is added from a different thread, we need to
call g_main_context_wakeup() to wake the main thread up to
start updating the timeline.
http://bugzilla.openedhand.com/show_bug.cgi?id=1637
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
Instead of keeping a list of all timelines, and connecting to
signals and weak notifies, simply keep a list of running timelines;
this greatly simplifies both the book-keeping, and also determining
if there are any running timelines.
http://bugzilla.openedhand.com/show_bug.cgi?id=1637
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
Remove code to advance the master clock after drawing a frame; if
there are any running timelines the master clock will do another
frame by itself, and the clock will be advanced before running
that frame.
With this change, there is no point in queueing an extra frame
redraw after completing a timeline, since we are always advancing
the timeline *before* redrawing, so remove that code as well.
(This does mean that calling clutter_timeline_stop() won't implicitly
cause the stage to be redrawn; this doesn't seem like something
an app should rely on in any case.)
http://bugzilla.openedhand.com/show_bug.cgi?id=1637
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
The commit 762873e79e is completely
and utterly wrong and I should have never pushed it.
Serves me well for trying to work on three different branches and
on three different things.
Currently, the clock source spins a redraw every time there is at
least a timeline running. If the timelines were not advanced in
the previous frame, though, because their interval is larger than
the vblanking interval then this will lead to excessive redraws of
the scenegraph even if nothing has changed.
To avoid this a simple guard should be set by the MasterClock::advance
method in case no timeline was effectively advanced, and checked
before dispatching the stage redraws.
The "started" signal is sent first after the timeline has been set to the
'running' state. For this reason, checking if the clock has any running
timelines running will always return true in the "started" signal handler:
the timeline that sent the signal is running.
What needs to be checked in the signal handler is if there are any
timelines running other than the one that emitted the ::started signal,
which we know is running anyway.
This prevents frames from being lost at the beginning of an animation when
a timeline is started after a quiescent period.
Fixes bug:
http://bugzilla.openedhand.com/show_bug.cgi?id=1617
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
The master clock is currently advanced using a frame source driven
by the default frame rate. This breaks the sync to vblank because
the vblanking rate could be different than 60 Hz -- or it might be
completely disabled (e.g. with CLUTTER_VBLANK=none).
We should be using the main loop to check if we have timelines
playing, and if so queue a redraw on the stages we own.
We should also prepare the subsequent frame at the end of the redraw
process, so if there are new redraw we will have the scene already
in place.
This makes Clutter redraw at the maximum frame rate, which is
limited by the vblanking frequency.
The method of ClutterTimeline that advances the timeline by a
delta (in millisecond) is going to be useful for testing the
timeline's behaviour -- and unbreak the timeline test suite that
was broken by the MasterClock merge.
Currently, all timelines install a timeout inside the TimeoutPool
they share. Every time the main loop spins, all the timeouts are
updated. This, in turn, will usually lead to redraws being queued
on the stages.
This behaviour leads to the potential starvation of timelines and
to excessive redraws.
One lesson learned from the games developers is that the scenegraph
should be prepared in its entirety before the GL paint sequence is
initiated. This means making sure that every ::new-frame signal
handler is called before clutter_redraw() is invoked.
In order to do so a TimeoutPool is not enough: we need a master
clock. The clock will be responsible for advancing all the active
timelines created inside a scene, but only when the stage is
being redrawn.
The sequence is:
+ queue_redraw() is invoked on an actor and bubbles up
to the stage
+ if no redraw() has already been scheduled, install an
idle handler with a known priority
+ inside the idle handler:
- advance the master clock, which will in turn advance
every playing timeline by the amount of milliseconds
elapsed since the last redraw; this will make every
playing timeline emit the ::new-frame signal
- queue a relayout
- call the redraw() method of the backend
This way we trade multiple timeouts with a single frame source
that only runs if a timeline is playing and queues redraws on
the various stages.
