mutter/src/tests/clutter/conform/timeline-interpolate.c

#define CLUTTER_DISABLE_DEPRECATION_WARNINGS
#include <stdlib.h>
#include <glib.h>
#include <clutter/clutter.h>

#include "tests/clutter-test-utils.h"

/* We ask for 1 frame per millisecond.
 * Whenever this rate can't be achieved then the timeline
 * will interpolate the number frames that should have
 * passed between timeouts. */
#define TEST_TIMELINE_FPS 1000
#define TEST_TIMELINE_DURATION 5000

/* We are at the mercy of the system scheduler so this
 * may not be a very reliable tolerance.
 *
 * It's set as very tolerable (1 ms shorter than the frame interval) as
 * otherwise CI, which are very prone to not get CPU time scheduled, tend to
 * often fail.
 */
#define TEST_ERROR_TOLERANCE ((TEST_TIMELINE_FPS / 4) - 1)

typedef struct _TestState
{
  ClutterTimeline *timeline;
  int64_t start_time;
  guint new_frame_counter;
  gint expected_frame;
  gint completion_count;
  gboolean passed;
} TestState;


static void
new_frame_cb (ClutterTimeline *timeline,
	      gint frame_num,
	      TestState *state)
{
  int64_t current_time;
  gint current_frame;
  glong msec_diff;
  gint loop_overflow = 0;
  static gint step = 1;

  current_time = g_get_real_time ();

  current_frame = clutter_timeline_get_elapsed_time (state->timeline);

  msec_diff = (current_time - state->start_time) / G_TIME_SPAN_MILLISECOND;

  /* If we expect to have interpolated past the end of the timeline
   * we keep track of the overflow so we can determine when
   * the next timeout will happen. We then clip expected_frames
   * to TEST_TIMELINE_DURATION since clutter-timeline
   * semantics guaranty this frame is always signaled before
   * looping */
  if (state->expected_frame > TEST_TIMELINE_DURATION)
    {
      loop_overflow = state->expected_frame - TEST_TIMELINE_DURATION;
      state->expected_frame = TEST_TIMELINE_DURATION;
    }

  if (current_frame >= (state->expected_frame-TEST_ERROR_TOLERANCE)
      && current_frame <= (state->expected_frame+TEST_ERROR_TOLERANCE))
    {
      g_test_message ("elapsed milliseconds=%-5li "
		      "expected frame=%-4i actual frame=%-4i (OK)",
		      msec_diff,
		      state->expected_frame,
		      current_frame);
    }
  else
    {
      g_test_message ("elapsed milliseconds=%-5li "
		      "expected frame=%-4i actual frame=%-4i (FAILED)",
		      msec_diff,
		      state->expected_frame,
		      current_frame);
      state->passed = FALSE;
    }

  if (step>0)
    {
      state->expected_frame = current_frame + (TEST_TIMELINE_FPS / 4);
      g_test_message ("Sleeping for 250ms "
		      "so next frame should be (%i + %i) = %i",
		      current_frame,
		      (TEST_TIMELINE_FPS / 4),
		      state->expected_frame);
      g_usleep (250000);
    }
  else
    {
      state->expected_frame = current_frame + TEST_TIMELINE_FPS;
      g_test_message ("Sleeping for 1sec "
		      "so next frame should be (%i + %i) = %i",
		      current_frame,
		      TEST_TIMELINE_FPS,
		      state->expected_frame);
      g_usleep (1000000);
    }

  if (current_frame >= TEST_TIMELINE_DURATION)
    {
      state->expected_frame += loop_overflow;
      state->expected_frame -= TEST_TIMELINE_DURATION;
      g_test_message ("End of timeline reached: "
		      "Wrapping expected frame too %i",
		      state->expected_frame);
    }

  state->new_frame_counter++;
  step = -step;
}


static void
completed_cb (ClutterTimeline *timeline,
	      TestState *state)
{
  state->completion_count++;

  if (state->completion_count == 2)
    {
      if (state->passed)
        clutter_main_quit ();
      else
        g_assert_not_reached ();
    }
}

static void
timeline_interpolation (void)
{
  ClutterActor *stage;
  TestState state;

  stage = clutter_test_get_stage ();

  state.timeline = 
    clutter_timeline_new_for_actor (stage, TEST_TIMELINE_DURATION);
  clutter_timeline_set_repeat_count (state.timeline, -1);
  g_signal_connect (G_OBJECT(state.timeline),
		    "new-frame",
		    G_CALLBACK(new_frame_cb),
		    &state);
  g_signal_connect (G_OBJECT(state.timeline),
		    "completed",
		    G_CALLBACK(completed_cb),
		    &state);

  state.completion_count = 0;
  state.new_frame_counter = 0;
  state.passed = TRUE;
  state.expected_frame = 0;

  clutter_actor_show (stage);

  state.start_time = g_get_real_time ();
  clutter_timeline_start (state.timeline);
  
  clutter_main();

  g_object_unref (state.timeline);
}

CLUTTER_TEST_SUITE (
  CLUTTER_TEST_UNIT ("/timeline/interpolate", timeline_interpolation)
)