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Count timeline frames using the FPS instead of an integer interval

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Bug 1495 - Timelines run 4% short

Previously the timelines were timed by calculating the interval
between each frame stored as an integer number of milliseconds so some
precision is lost. For example, requesting 60 frames per second gets
converted to 16 ms per frame which is actually 62.5 frames per
second. This makes the timeline shorter by 4%.

This patch merges the common code for timing from the timeout pools
and frame sources into an internal clutter-timeout-interval file. This
stores the interval directly as the FPS and counts the number of
frames that have been reached instead of the elapsed time.
This commit is contained in:
Neil Roberts
2009-03-09 17:12:27 +00:00
parent 2c1c836417
commit a93a93d007
10 changed files with 243 additions and 159 deletions
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79
clutter/clutter-frame-source.c
View File

@@ -3,7 +3,7 @@
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Matthew Allum <mallum@openedhand.com>
* Authored By Neil Roberts <neil@linux.intel.com>
*
* Copyright (C) 2008 OpenedHand
*
@@ -28,6 +28,7 @@
#endif
#include "clutter-frame-source.h"
#include "clutter-timeout-interval.h"
typedef struct _ClutterFrameSource ClutterFrameSource;
@@ -35,8 +36,7 @@ struct _ClutterFrameSource
{
GSource source;
GTimeVal start_time;
guint last_time, frame_time;
ClutterTimeoutInterval timeout;
};
static gboolean clutter_frame_source_prepare (GSource *source, gint *timeout);
@@ -45,7 +45,7 @@ static gboolean clutter_frame_source_dispatch (GSource *source,
GSourceFunc callback,
gpointer user_data);
static GSourceFuncs clutter_frame_source_funcs =
static GSourceFuncs clutter_frame_source_funcs =
{
clutter_frame_source_prepare,
clutter_frame_source_check,
@@ -57,7 +57,7 @@ static GSourceFuncs clutter_frame_source_funcs =
* clutter_frame_source_add_full:
* @priority: the priority of the frame source. Typically this will be in the
* range between #G_PRIORITY_DEFAULT and #G_PRIORITY_HIGH.
* @interval: the time between calls to the function, in milliseconds
* @fps: the number of times per second to call the function
* @func: function to call
* @data: data to pass to the function
* @notify: function to call when the timeout source is removed
@@ -74,7 +74,7 @@ static GSourceFuncs clutter_frame_source_funcs =
* the interval time to execute then the function will be called again
* half the interval time after it finished. In contrast
* g_timeout_add_full() would not fire until a full interval after the
* function completes so the delay between calls would be @interval *
* function completes so the delay between calls would be 1.0 / @fps *
* 1.5. This function does not however try to invoke the function
* multiple times to catch up missing frames if @func takes more than
* @interval ms to execute.
@@ -85,7 +85,7 @@ static GSourceFuncs clutter_frame_source_funcs =
*/
guint
clutter_frame_source_add_full (gint priority,
guint interval,
guint fps,
GSourceFunc func,
gpointer data,
GDestroyNotify notify)
@@ -95,9 +95,7 @@ clutter_frame_source_add_full (gint priority,
sizeof (ClutterFrameSource));
ClutterFrameSource *frame_source = (ClutterFrameSource *) source;
frame_source->last_time = 0;
frame_source->frame_time = interval;
g_get_current_time (&frame_source->start_time);
_clutter_timeout_interval_init (&frame_source->timeout, fps);
if (priority != G_PRIORITY_DEFAULT)
g_source_set_priority (source, priority);
@@ -113,7 +111,7 @@ clutter_frame_source_add_full (gint priority,
/**
* clutter_frame_source_add:
* @interval: the time between calls to the function, in milliseconds
* @fps: the number of times per second to call the function
* @func: function to call
* @data: data to pass to the function
*
@@ -124,55 +122,25 @@ clutter_frame_source_add_full (gint priority,
* Since: 0.8
*/
guint
clutter_frame_source_add (guint interval,
clutter_frame_source_add (guint fps,
GSourceFunc func,
gpointer data)
{
return clutter_frame_source_add_full (G_PRIORITY_DEFAULT,
interval, func, data, NULL);
}
static guint
clutter_frame_source_get_ticks (ClutterFrameSource *frame_source)
{
GTimeVal time_now;
g_source_get_current_time ((GSource *) frame_source, &time_now);
return (time_now.tv_sec - frame_source->start_time.tv_sec) * 1000
+ (time_now.tv_usec - frame_source->start_time.tv_usec) / 1000;
fps, func, data, NULL);
}
static gboolean
clutter_frame_source_prepare (GSource *source, gint *timeout)
clutter_frame_source_prepare (GSource *source, gint *delay)
{
ClutterFrameSource *frame_source = (ClutterFrameSource *) source;
GTimeVal current_time;
guint now = clutter_frame_source_get_ticks (frame_source);
g_source_get_current_time (source, &current_time);
/* If time has gone backwards or the time since the last frame is
greater than the two frames worth then reset the time and do a
frame now */
if (frame_source->last_time > now ||
(now - frame_source->last_time) > frame_source->frame_time * 2)
{
frame_source->last_time = now - frame_source->frame_time;
if (timeout)
*timeout = 0;
return TRUE;
}
else if (now - frame_source->last_time >= frame_source->frame_time)
{
if (timeout)
*timeout = 0;
return TRUE;
}
else
{
if (timeout)
*timeout = frame_source->frame_time + frame_source->last_time - now;
return FALSE;
}
return _clutter_timeout_interval_prepare (&current_time,
&frame_source->timeout,
delay);
}
static gboolean
@@ -183,16 +151,11 @@ clutter_frame_source_check (GSource *source)
static gboolean
clutter_frame_source_dispatch (GSource *source,
GSourceFunc callback,
gpointer user_data)
GSourceFunc callback,
gpointer user_data)
{
ClutterFrameSource *frame_source = (ClutterFrameSource *) source;
if ((* callback) (user_data))
{
frame_source->last_time += frame_source->frame_time;
return TRUE;
}
else
return FALSE;
return _clutter_timeout_interval_dispatch (&frame_source->timeout,
callback, user_data);
}