gtk2/gdk/gdkframeclockidle.c
Chris Williams 3246d6a738 gdkframeclockidle: Don't permanently skew frame time
Since commit 3b2f9395, the frame time may be set into the future, so
only ensure monotonicity, and don't store the offset. This prevents the
frame time from becoming out of sync with g_get_monotonic_time().

Fixes #1612
2019-04-11 13:25:18 -04:00

614 lines
19 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 "gdkinternals.h"
#include "gdkframeclockprivate.h"
#include "gdkframeclockidle.h"
#include "gdk.h"
#ifdef G_OS_WIN32
#include <windows.h>
#endif
#define FRAME_INTERVAL 16667 /* microseconds */
struct _GdkFrameClockIdlePrivate
{
gint64 frame_time;
gint64 min_next_frame_time;
gint64 sleep_serial;
guint flush_idle_id;
guint paint_idle_id;
guint freeze_count;
guint updating_count;
GdkFrameClockPhase requested;
GdkFrameClockPhase phase;
guint in_paint_idle : 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->frame_time = g_get_monotonic_time (); /* more sane than zero */
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);
}
static gint64
compute_frame_time (GdkFrameClockIdle *idle)
{
GdkFrameClockIdlePrivate *priv = idle->priv;
gint64 computed_frame_time;
computed_frame_time = g_get_monotonic_time ();
/* ensure monotonicity of frame time */
if (computed_frame_time <= priv->frame_time)
computed_frame_time = priv->frame_time + 1;
return computed_frame_time;
}
static gint64
gdk_frame_clock_idle_get_frame_time (GdkFrameClock *clock)
{
GdkFrameClockIdlePrivate *priv = GDK_FRAME_CLOCK_IDLE (clock)->priv;
gint64 computed_frame_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)
return priv->frame_time;
/* Outside a paint, pick something close to "now" */
computed_frame_time = compute_frame_time (GDK_FRAME_CLOCK_IDLE (clock));
/* 16ms is 60fps. We only update frame time that often because we'd
* like to try to keep animations on the same start times.
* get_frame_time() would normally be used outside of a paint to
* record an animation start time for example.
*/
if ((computed_frame_time - priv->frame_time) > FRAME_INTERVAL)
priv->frame_time = computed_frame_time;
return priv->frame_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)
{
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 = compute_frame_time (clock_idle);
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 = gdk_threads_add_timeout_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_idle_id = gdk_threads_add_timeout_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;
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;
gint64 reset_frame_time;
gint64 smoothest_frame_time;
gint64 frame_time_error;
GdkFrameTimings *prev_timings =
gdk_frame_clock_get_current_timings (clock);
if (prev_timings && prev_timings->refresh_interval)
frame_interval = prev_timings->refresh_interval;
/* We are likely not getting precisely even callbacks in real
* time, particularly if the event loop is busy.
* This is a documented limitation in the precision of
* gdk_threads_add_timeout_full and g_timeout_add_full.
*
* In order to avoid this imprecision from compounding between
* frames and affecting visual smoothness, we correct frame_time
* to more precisely match the even refresh interval of the
* physical display. This also means we proactively avoid (most)
* missed frames before they occur.
*/
smoothest_frame_time = priv->frame_time + frame_interval;
reset_frame_time = compute_frame_time (clock_idle);
frame_time_error = ABS (reset_frame_time - smoothest_frame_time);
if (frame_time_error >= frame_interval)
priv->frame_time = reset_frame_time;
else
priv->frame_time = smoothest_frame_time;
_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->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;
}
/* 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);
}
}
/* 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 /* G_ENABLE_DEBUG */
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");
}
/* 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 /* G_ENABLE_DEBUG */
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);
}
}
/* 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 */
}
/* fallthrough */
case GDK_FRAME_CLOCK_PHASE_RESUME_EVENTS:
;
}
}
#ifdef G_ENABLE_DEBUG
if (GDK_DEBUG_CHECK (FRAMES))
{
if (timings && timings->complete)
_gdk_frame_clock_debug_print_timings (clock, timings);
}
#endif /* G_ENABLE_DEBUG */
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->frame_time);
maybe_start_idle (clock_idle);
}
if (priv->freeze_count == 0)
priv->sleep_serial = get_sleep_serial ();
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);
}
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);
}
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;
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);
/* 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 ();
}
}
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);
}