8f60d5a3a2
Starting from the 2.27 cycle, GLib is exposing a monotonic clock with microseconds granularity throughout the time-based API. We can start using it, given that the old, non-monotonic version is going to be deprecated by the same cycle.
140 lines
3.9 KiB
C
140 lines
3.9 KiB
C
/*
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* Clutter.
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*
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* An OpenGL based 'interactive canvas' library.
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*
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* Authored By Neil Roberts <neil@linux.intel.com>
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*
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* Copyright (C) 2009 Intel Corporation.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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/* This file contains the common code to check whether an interval has
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expired used in clutter-frame-source and clutter-timeout-pool. */
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#include "clutter-timeout-interval.h"
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void
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_clutter_timeout_interval_init (ClutterTimeoutInterval *interval,
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guint fps)
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{
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#if GLIB_CHECK_VERSION (2, 27, 3)
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interval->start_time = g_get_monotonic_time () / 1000;
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#else
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{
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GTimeVal start_time;
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g_get_current_time (&start_time);
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interval->start_time = start_time.tv_sec * 1000
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+ start_time.tv_usec / 1000;
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}
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#endif
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interval->fps = fps;
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interval->frame_count = 0;
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}
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static gint64
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_clutter_timeout_interval_get_ticks (gint64 current_time,
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ClutterTimeoutInterval *interval)
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{
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return MAX (current_time - interval->start_time, 0);
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}
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gboolean
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_clutter_timeout_interval_prepare (gint64 current_time,
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ClutterTimeoutInterval *interval,
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gint *delay)
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{
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gint elapsed_time, new_frame_num;
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elapsed_time = _clutter_timeout_interval_get_ticks (current_time, interval);
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new_frame_num = elapsed_time * interval->fps / 1000;
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/* If time has gone backwards or the time since the last frame is
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greater than the two frames worth then reset the time and do a
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frame now */
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if (new_frame_num < interval->frame_count ||
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new_frame_num - interval->frame_count > 2)
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{
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/* Get the frame time rounded up to the nearest ms */
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guint frame_time = (1000 + interval->fps - 1) / interval->fps;
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/* Reset the start time */
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interval->start_time = current_time;
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/* Move the start time as if one whole frame has elapsed */
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interval->start_time -= frame_time;
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interval->frame_count = 0;
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if (delay)
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*delay = 0;
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return TRUE;
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}
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else if (new_frame_num > interval->frame_count)
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{
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if (delay)
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*delay = 0;
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return TRUE;
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}
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else
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{
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if (delay)
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*delay = ((interval->frame_count + 1) * 1000 / interval->fps
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- elapsed_time);
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return FALSE;
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}
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}
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gboolean
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_clutter_timeout_interval_dispatch (ClutterTimeoutInterval *interval,
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GSourceFunc callback,
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gpointer user_data)
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{
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if ((* callback) (user_data))
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{
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interval->frame_count++;
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return TRUE;
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}
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return FALSE;
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}
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gint
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_clutter_timeout_interval_compare_expiration (const ClutterTimeoutInterval *a,
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const ClutterTimeoutInterval *b)
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{
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guint a_delay = 1000 / a->fps;
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guint b_delay = 1000 / b->fps;
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gint64 b_difference;
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gint comparison;
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b_difference = a->start_time - b->start_time;
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comparison = ((gint) ((a->frame_count + 1) * a_delay)
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- (gint) ((b->frame_count + 1) * b_delay + b_difference));
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return (comparison < 0 ? -1
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: comparison > 0 ? 1
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: 0);
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}
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