gtk/gdk/gdkframeclockidle.c
Yariv Barkan f5de46670b frame clock: schedule in refresh intervals
When the application does not receive "frame drawn" signals we schedule
the clock to run more or less at intervals equal to the last known
refresh interval. In order to minimize clock skew we have to aim for
exact intervals.
2020-06-05 11:57:49 +02:00

699 lines
23 KiB
C

/* GDK - The GIMP Drawing Kit
* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GTK+ Team and others 1997-2010. See the AUTHORS
* file for a list of people on the GTK+ Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GTK+ at ftp://ftp.gtk.org/pub/gtk/.
*/
#include "config.h"
#include "gdkframeclockidleprivate.h"
#include "gdkinternals.h"
#include "gdkframeclockprivate.h"
#include "gdk.h"
#include "gdkprofilerprivate.h"
#ifdef G_OS_WIN32
#include <windows.h>
#endif
#define FRAME_INTERVAL 16667 /* microseconds */
struct _GdkFrameClockIdlePrivate
{
gint64 frame_time; /* The exact time we last ran the clock cycle, or 0 if never */
gint64 smoothed_frame_time_base; /* A grid-aligned version of frame_time (grid size == refresh period), never more than half a grid from frame_time */
gint64 smoothed_frame_time_period; /* The grid size that smoothed_frame_time_base is aligned to */
gint64 smoothed_frame_time_reported; /* Ensures we are always monotonic */
gint64 min_next_frame_time; /* We're not synced to vblank, so wait at least until this before next cycle to avoid busy looping */
gint64 sleep_serial;
gint64 freeze_time;
guint flush_idle_id;
guint paint_idle_id;
guint freeze_count;
guint updating_count;
GdkFrameClockPhase requested;
GdkFrameClockPhase phase;
guint in_paint_idle : 1;
guint paint_is_thaw : 1;
#ifdef G_OS_WIN32
guint begin_period : 1;
#endif
};
static gboolean gdk_frame_clock_flush_idle (void *data);
static gboolean gdk_frame_clock_paint_idle (void *data);
G_DEFINE_TYPE_WITH_PRIVATE (GdkFrameClockIdle, gdk_frame_clock_idle, GDK_TYPE_FRAME_CLOCK)
static gint64 sleep_serial;
static gint64 sleep_source_prepare_time;
static GSource *sleep_source;
static gboolean
sleep_source_prepare (GSource *source,
gint *timeout)
{
sleep_source_prepare_time = g_source_get_time (source);
*timeout = -1;
return FALSE;
}
static gboolean
sleep_source_check (GSource *source)
{
if (g_source_get_time (source) != sleep_source_prepare_time)
sleep_serial++;
return FALSE;
}
static gboolean
sleep_source_dispatch (GSource *source,
GSourceFunc callback,
gpointer user_data)
{
return TRUE;
}
static GSourceFuncs sleep_source_funcs = {
sleep_source_prepare,
sleep_source_check,
sleep_source_dispatch,
NULL /* finalize */
};
static gint64
get_sleep_serial (void)
{
if (sleep_source == NULL)
{
sleep_source = g_source_new (&sleep_source_funcs, sizeof (GSource));
g_source_set_priority (sleep_source, G_PRIORITY_HIGH);
g_source_attach (sleep_source, NULL);
g_source_unref (sleep_source);
}
return sleep_serial;
}
static void
gdk_frame_clock_idle_init (GdkFrameClockIdle *frame_clock_idle)
{
GdkFrameClockIdlePrivate *priv;
frame_clock_idle->priv = priv =
gdk_frame_clock_idle_get_instance_private (frame_clock_idle);
priv->freeze_count = 0;
}
static void
gdk_frame_clock_idle_dispose (GObject *object)
{
GdkFrameClockIdlePrivate *priv = GDK_FRAME_CLOCK_IDLE (object)->priv;
if (priv->flush_idle_id != 0)
{
g_source_remove (priv->flush_idle_id);
priv->flush_idle_id = 0;
}
if (priv->paint_idle_id != 0)
{
g_source_remove (priv->paint_idle_id);
priv->paint_idle_id = 0;
}
#ifdef G_OS_WIN32
if (priv->begin_period)
{
timeEndPeriod(1);
priv->begin_period = FALSE;
}
#endif
G_OBJECT_CLASS (gdk_frame_clock_idle_parent_class)->dispose (object);
}
/* Note: This is never called on first frame, so
* smoothed_frame_time_base != 0 and we have a valid frame_interval. */
static gint64
compute_smooth_frame_time (GdkFrameClock *clock,
gint64 new_frame_time,
gboolean new_frame_time_is_vsync_related,
gint64 smoothed_frame_time_base,
gint64 frame_interval)
{
GdkFrameClockIdlePrivate *priv = GDK_FRAME_CLOCK_IDLE (clock)->priv;
int frames_passed;
gint64 new_smoothed_time;
gint64 current_error;
gint64 correction_magnitude;
/* Consecutive frame, assume it is an integer number of frames later, so round to nearest such */
/* NOTE: This is >= 0, because smoothed_frame_time_base is < frame_interval/2 from old_frame_time
* and new_frame_time >= old_frame_time. */
frames_passed = (new_frame_time - smoothed_frame_time_base + frame_interval / 2) / frame_interval;
/* We use an approximately whole number of frames in the future from
* last smoothed frame time. This way we avoid minor jitter in the
* frame times making the animation speed uneven, but still animate
* evenly in case of whole frame skips. */
new_smoothed_time = smoothed_frame_time_base + frames_passed * frame_interval;
/* However, sometimes the smoothed time is too much off from the
* real time. For example, if the first frame clock cycle happened
* not due to a frame rendering but an input event, then
* new_frame_time could happen to be near the middle between two
* frames. If that happens and we then start regularly animating at
* the refresh_rate, then the jitter in the real time may cause us
* to randomly sometimes round up, and sometimes down.
*
* To combat this we converge the smooth time towards the real time
* in a way that is slow when they are near and fast when they are
* far from each other.
*
* This is done by using the square of the error as the correction
* magnitude. I.e. if the error is 0.5 frame, we correct by
* 0.5*0.5=0.25 frame, if the error is 0.25 we correct by 0.125, if
* the error is 0.1, frame we correct by 0.01 frame, etc.
*
* The actual computation is:
* (current_error/frame_interval)*(current_error/frame_interval)*frame_interval
* But this can be simplified as below.
*
* Note: We only do this correction if the new frame is caused by a
* thaw of the frame clock, so that we know the time is actually
* related to the physical vblank. For frameclock cycles triggered
* by other events we always step up in whole frames from the last
* reported time.
*/
if (new_frame_time_is_vsync_related)
{
current_error = new_smoothed_time - new_frame_time;
correction_magnitude = current_error * current_error / frame_interval; /* Note, this is always > 0 due to the square */
if (current_error > 0)
new_smoothed_time -= correction_magnitude;
else
new_smoothed_time += correction_magnitude;
}
/* Ensure we're always monotonic */
if (new_smoothed_time <= priv->smoothed_frame_time_reported)
new_smoothed_time = priv->smoothed_frame_time_reported;
return new_smoothed_time;
}
static gint64
gdk_frame_clock_idle_get_frame_time (GdkFrameClock *clock)
{
GdkFrameClockIdlePrivate *priv = GDK_FRAME_CLOCK_IDLE (clock)->priv;
gint64 now;
gint64 new_smoothed_time;
/* can't change frame time during a paint */
if (priv->phase != GDK_FRAME_CLOCK_PHASE_NONE &&
priv->phase != GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS &&
(priv->phase != GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT || priv->in_paint_idle))
return priv->smoothed_frame_time_base;
/* Outside a paint, pick something smoothed close to now */
now = g_get_monotonic_time ();
/* First time frame, just return something */
if (priv->smoothed_frame_time_base == 0)
{
priv->smoothed_frame_time_reported = now;
return now;
}
/* Since time is monotonic this is <= what we will pick for the next cycle, but
more likely than not it will be equal if we're doing a constant animation. */
new_smoothed_time = compute_smooth_frame_time (clock, now, FALSE,
priv->smoothed_frame_time_base,
priv->smoothed_frame_time_period);
priv->smoothed_frame_time_reported = new_smoothed_time;
return new_smoothed_time;
}
#define RUN_FLUSH_IDLE(priv) \
((priv)->freeze_count == 0 && \
((priv)->requested & GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS) != 0)
/* The reason why we track updating_count separately here and don't
* just add GDK_FRAME_CLOCK_PHASE_UPDATE into ->request on every frame
* is so that we can avoid doing one more frame when an animation
* is cancelled.
*/
#define RUN_PAINT_IDLE(priv) \
((priv)->freeze_count == 0 && \
(((priv)->requested & ~GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS) != 0 || \
(priv)->updating_count > 0))
static void
maybe_start_idle (GdkFrameClockIdle *clock_idle,
gboolean caused_by_thaw)
{
GdkFrameClockIdlePrivate *priv = clock_idle->priv;
if (RUN_FLUSH_IDLE (priv) || RUN_PAINT_IDLE (priv))
{
guint min_interval = 0;
if (priv->min_next_frame_time != 0)
{
gint64 now = g_get_monotonic_time ();
gint64 min_interval_us = MAX (priv->min_next_frame_time, now) - now;
min_interval = (min_interval_us + 500) / 1000;
}
if (priv->flush_idle_id == 0 && RUN_FLUSH_IDLE (priv))
{
priv->flush_idle_id = g_timeout_add_full (GDK_PRIORITY_EVENTS + 1,
min_interval,
gdk_frame_clock_flush_idle,
g_object_ref (clock_idle),
(GDestroyNotify) g_object_unref);
g_source_set_name_by_id (priv->flush_idle_id, "[gtk] gdk_frame_clock_flush_idle");
}
if (!priv->in_paint_idle &&
priv->paint_idle_id == 0 && RUN_PAINT_IDLE (priv))
{
priv->paint_is_thaw = caused_by_thaw;
priv->paint_idle_id = g_timeout_add_full (GDK_PRIORITY_REDRAW,
min_interval,
gdk_frame_clock_paint_idle,
g_object_ref (clock_idle),
(GDestroyNotify) g_object_unref);
g_source_set_name_by_id (priv->paint_idle_id, "[gtk] gdk_frame_clock_paint_idle");
}
}
}
static void
maybe_stop_idle (GdkFrameClockIdle *clock_idle)
{
GdkFrameClockIdlePrivate *priv = clock_idle->priv;
if (priv->flush_idle_id != 0 && !RUN_FLUSH_IDLE (priv))
{
g_source_remove (priv->flush_idle_id);
priv->flush_idle_id = 0;
}
if (priv->paint_idle_id != 0 && !RUN_PAINT_IDLE (priv))
{
g_source_remove (priv->paint_idle_id);
priv->paint_idle_id = 0;
}
}
static gint64
compute_min_next_frame_time (GdkFrameClockIdle *clock_idle,
gint64 last_frame_time)
{
gint64 presentation_time;
gint64 refresh_interval;
gdk_frame_clock_get_refresh_info (GDK_FRAME_CLOCK (clock_idle),
last_frame_time,
&refresh_interval, &presentation_time);
if (presentation_time == 0)
return last_frame_time + refresh_interval;
else
return presentation_time + refresh_interval / 2;
}
static gboolean
gdk_frame_clock_flush_idle (void *data)
{
GdkFrameClock *clock = GDK_FRAME_CLOCK (data);
GdkFrameClockIdle *clock_idle = GDK_FRAME_CLOCK_IDLE (clock);
GdkFrameClockIdlePrivate *priv = clock_idle->priv;
priv->flush_idle_id = 0;
if (priv->phase != GDK_FRAME_CLOCK_PHASE_NONE)
return FALSE;
priv->phase = GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS;
priv->requested &= ~GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS;
_gdk_frame_clock_emit_flush_events (clock);
if ((priv->requested & ~GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS) != 0 ||
priv->updating_count > 0)
priv->phase = GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT;
else
priv->phase = GDK_FRAME_CLOCK_PHASE_NONE;
return FALSE;
}
static gboolean
gdk_frame_clock_paint_idle (void *data)
{
GdkFrameClock *clock = GDK_FRAME_CLOCK (data);
GdkFrameClockIdle *clock_idle = GDK_FRAME_CLOCK_IDLE (clock);
GdkFrameClockIdlePrivate *priv = clock_idle->priv;
gboolean skip_to_resume_events;
GdkFrameTimings *timings = NULL;
gint64 before = g_get_monotonic_time ();
priv->paint_idle_id = 0;
priv->in_paint_idle = TRUE;
priv->min_next_frame_time = 0;
skip_to_resume_events =
(priv->requested & ~(GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS | GDK_FRAME_CLOCK_PHASE_RESUME_EVENTS)) == 0 &&
priv->updating_count == 0;
if (priv->phase > GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT)
{
timings = gdk_frame_clock_get_current_timings (clock);
}
if (!skip_to_resume_events)
{
switch (priv->phase)
{
case GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS:
break;
case GDK_FRAME_CLOCK_PHASE_NONE:
case GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT:
if (priv->freeze_count == 0)
{
gint64 frame_interval = FRAME_INTERVAL;
GdkFrameTimings *prev_timings = gdk_frame_clock_get_current_timings (clock);
if (prev_timings && prev_timings->refresh_interval)
frame_interval = prev_timings->refresh_interval;
priv->frame_time = g_get_monotonic_time ();
if (priv->smoothed_frame_time_base == 0)
{
/* First frame */
priv->smoothed_frame_time_base = priv->frame_time;
priv->smoothed_frame_time_period = frame_interval;
}
else
{
priv->smoothed_frame_time_base =
compute_smooth_frame_time (clock, priv->frame_time,
priv->paint_is_thaw,
priv->smoothed_frame_time_base,
priv->smoothed_frame_time_period);
priv->smoothed_frame_time_period = frame_interval;
}
priv->smoothed_frame_time_reported = priv->smoothed_frame_time_base;
_gdk_frame_clock_begin_frame (clock);
/* Note "current" is different now so timings != prev_timings */
timings = gdk_frame_clock_get_current_timings (clock);
timings->frame_time = priv->frame_time;
timings->smoothed_frame_time = priv->smoothed_frame_time_base;
timings->slept_before = priv->sleep_serial != get_sleep_serial ();
priv->phase = GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT;
/* We always emit ::before-paint and ::after-paint if
* any of the intermediate phases are requested and
* they don't get repeated if you freeze/thaw while
* in them.
*/
priv->requested &= ~GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT;
_gdk_frame_clock_emit_before_paint (clock);
priv->phase = GDK_FRAME_CLOCK_PHASE_UPDATE;
}
G_GNUC_FALLTHROUGH;
case GDK_FRAME_CLOCK_PHASE_UPDATE:
if (priv->freeze_count == 0)
{
if ((priv->requested & GDK_FRAME_CLOCK_PHASE_UPDATE) != 0 ||
priv->updating_count > 0)
{
priv->requested &= ~GDK_FRAME_CLOCK_PHASE_UPDATE;
_gdk_frame_clock_emit_update (clock);
}
}
G_GNUC_FALLTHROUGH;
case GDK_FRAME_CLOCK_PHASE_LAYOUT:
if (priv->freeze_count == 0)
{
int iter;
#ifdef G_ENABLE_DEBUG
if (GDK_DEBUG_CHECK (FRAMES))
{
if (priv->phase != GDK_FRAME_CLOCK_PHASE_LAYOUT &&
(priv->requested & GDK_FRAME_CLOCK_PHASE_LAYOUT))
timings->layout_start_time = g_get_monotonic_time ();
}
#endif
priv->phase = GDK_FRAME_CLOCK_PHASE_LAYOUT;
/* We loop in the layout phase, because we don't want to progress
* into the paint phase with invalid size allocations. This may
* happen in some situation like races between user window
* resizes and natural size changes.
*/
iter = 0;
while ((priv->requested & GDK_FRAME_CLOCK_PHASE_LAYOUT) &&
priv->freeze_count == 0 && iter++ < 4)
{
priv->requested &= ~GDK_FRAME_CLOCK_PHASE_LAYOUT;
_gdk_frame_clock_emit_layout (clock);
}
if (iter == 5)
g_warning ("gdk-frame-clock: layout continuously requested, giving up after 4 tries");
}
G_GNUC_FALLTHROUGH;
case GDK_FRAME_CLOCK_PHASE_PAINT:
if (priv->freeze_count == 0)
{
#ifdef G_ENABLE_DEBUG
if (GDK_DEBUG_CHECK (FRAMES))
{
if (priv->phase != GDK_FRAME_CLOCK_PHASE_PAINT &&
(priv->requested & GDK_FRAME_CLOCK_PHASE_PAINT))
timings->paint_start_time = g_get_monotonic_time ();
}
#endif
priv->phase = GDK_FRAME_CLOCK_PHASE_PAINT;
if (priv->requested & GDK_FRAME_CLOCK_PHASE_PAINT)
{
priv->requested &= ~GDK_FRAME_CLOCK_PHASE_PAINT;
_gdk_frame_clock_emit_paint (clock);
}
}
G_GNUC_FALLTHROUGH;
case GDK_FRAME_CLOCK_PHASE_AFTER_PAINT:
if (priv->freeze_count == 0)
{
priv->requested &= ~GDK_FRAME_CLOCK_PHASE_AFTER_PAINT;
_gdk_frame_clock_emit_after_paint (clock);
/* the ::after-paint phase doesn't get repeated on freeze/thaw,
*/
priv->phase = GDK_FRAME_CLOCK_PHASE_NONE;
}
#ifdef G_ENABLE_DEBUG
if (GDK_DEBUG_CHECK (FRAMES))
timings->frame_end_time = g_get_monotonic_time ();
#endif /* G_ENABLE_DEBUG */
G_GNUC_FALLTHROUGH;
case GDK_FRAME_CLOCK_PHASE_RESUME_EVENTS:
default:
;
}
}
if (priv->requested & GDK_FRAME_CLOCK_PHASE_RESUME_EVENTS)
{
priv->requested &= ~GDK_FRAME_CLOCK_PHASE_RESUME_EVENTS;
_gdk_frame_clock_emit_resume_events (clock);
}
if (priv->freeze_count == 0)
priv->phase = GDK_FRAME_CLOCK_PHASE_NONE;
priv->in_paint_idle = FALSE;
/* If there is throttling in the backend layer, then we'll do another
* update as soon as the backend unthrottles (if there is work to do),
* otherwise we need to figure when the next frame should be.
*/
if (priv->freeze_count == 0)
{
priv->min_next_frame_time = compute_min_next_frame_time (clock_idle,
priv->smoothed_frame_time_base);
maybe_start_idle (clock_idle, FALSE);
}
if (priv->freeze_count == 0)
priv->sleep_serial = get_sleep_serial ();
if (GDK_PROFILER_IS_RUNNING)
gdk_profiler_end_mark (before, "frameclock cycle", NULL);
return FALSE;
}
static void
gdk_frame_clock_idle_request_phase (GdkFrameClock *clock,
GdkFrameClockPhase phase)
{
GdkFrameClockIdle *clock_idle = GDK_FRAME_CLOCK_IDLE (clock);
GdkFrameClockIdlePrivate *priv = clock_idle->priv;
priv->requested |= phase;
maybe_start_idle (clock_idle, FALSE);
}
static void
gdk_frame_clock_idle_begin_updating (GdkFrameClock *clock)
{
GdkFrameClockIdle *clock_idle = GDK_FRAME_CLOCK_IDLE (clock);
GdkFrameClockIdlePrivate *priv = clock_idle->priv;
#ifdef G_OS_WIN32
/* We need a higher resolution timer while doing animations */
if (priv->updating_count == 0 && !priv->begin_period)
{
timeBeginPeriod(1);
priv->begin_period = TRUE;
}
#endif
priv->updating_count++;
maybe_start_idle (clock_idle, FALSE);
}
static void
gdk_frame_clock_idle_end_updating (GdkFrameClock *clock)
{
GdkFrameClockIdle *clock_idle = GDK_FRAME_CLOCK_IDLE (clock);
GdkFrameClockIdlePrivate *priv = clock_idle->priv;
g_return_if_fail (priv->updating_count > 0);
priv->updating_count--;
maybe_stop_idle (clock_idle);
#ifdef G_OS_WIN32
if (priv->updating_count == 0 && priv->begin_period)
{
timeEndPeriod(1);
priv->begin_period = FALSE;
}
#endif
}
static void
gdk_frame_clock_idle_freeze (GdkFrameClock *clock)
{
GdkFrameClockIdle *clock_idle = GDK_FRAME_CLOCK_IDLE (clock);
GdkFrameClockIdlePrivate *priv = clock_idle->priv;
if (priv->freeze_count == 0)
{
if (GDK_PROFILER_IS_RUNNING)
priv->freeze_time = g_get_monotonic_time ();
}
priv->freeze_count++;
maybe_stop_idle (clock_idle);
}
static void
gdk_frame_clock_idle_thaw (GdkFrameClock *clock)
{
GdkFrameClockIdle *clock_idle = GDK_FRAME_CLOCK_IDLE (clock);
GdkFrameClockIdlePrivate *priv = clock_idle->priv;
g_return_if_fail (priv->freeze_count > 0);
priv->freeze_count--;
if (priv->freeze_count == 0)
{
maybe_start_idle (clock_idle, TRUE);
/* If nothing is requested so we didn't start an idle, we need
* to skip to the end of the state chain, since the idle won't
* run and do it for us.
*/
if (priv->paint_idle_id == 0)
priv->phase = GDK_FRAME_CLOCK_PHASE_NONE;
priv->sleep_serial = get_sleep_serial ();
if (GDK_PROFILER_IS_RUNNING)
{
if (priv->freeze_time != 0)
{
gdk_profiler_end_mark (priv->freeze_time,
"frameclock frozen", NULL);
priv->freeze_time = 0;
}
}
}
}
static void
gdk_frame_clock_idle_class_init (GdkFrameClockIdleClass *klass)
{
GObjectClass *gobject_class = (GObjectClass*) klass;
GdkFrameClockClass *frame_clock_class = (GdkFrameClockClass *)klass;
gobject_class->dispose = gdk_frame_clock_idle_dispose;
frame_clock_class->get_frame_time = gdk_frame_clock_idle_get_frame_time;
frame_clock_class->request_phase = gdk_frame_clock_idle_request_phase;
frame_clock_class->begin_updating = gdk_frame_clock_idle_begin_updating;
frame_clock_class->end_updating = gdk_frame_clock_idle_end_updating;
frame_clock_class->freeze = gdk_frame_clock_idle_freeze;
frame_clock_class->thaw = gdk_frame_clock_idle_thaw;
}
GdkFrameClock *
_gdk_frame_clock_idle_new (void)
{
GdkFrameClockIdle *clock;
clock = g_object_new (GDK_TYPE_FRAME_CLOCK_IDLE, NULL);
return GDK_FRAME_CLOCK (clock);
}