Add frame time chart

Add a chart at the bottom 10% of the screen where each
bar represents the time the frame took to be painted. The
red line represents the maximum time to draw. For example,
if you are on a 60Hz monitor, the red line means 16.6667
miliseconds.

This covers both layout time (green) and paint time (blue).

Enjoy.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/502

clutter/clutter/clutter-main.c

@@ -143,6 +143,7 @@ static const GDebugKey clutter_paint_debug_keys[] = {
   { "continuous-redraw", CLUTTER_DEBUG_CONTINUOUS_REDRAW },
   { "paint-deform-tiles", CLUTTER_DEBUG_PAINT_DEFORM_TILES },
   { "damage-region", CLUTTER_DEBUG_PAINT_DAMAGE_REGION },
+  { "frame-time", CLUTTER_DEBUG_PAINT_FRAME_TIME },
 };
 
 static void

clutter/clutter/clutter-main.h

@@ -74,6 +74,7 @@ typedef enum
   CLUTTER_DEBUG_CONTINUOUS_REDRAW       = 1 << 6,
   CLUTTER_DEBUG_PAINT_DEFORM_TILES      = 1 << 7,
   CLUTTER_DEBUG_PAINT_DAMAGE_REGION     = 1 << 8,
+  CLUTTER_DEBUG_PAINT_FRAME_TIME        = 1 << 9,
 } ClutterDrawDebugFlag;
 
 /**

clutter/clutter/clutter-stage-private.h

@@ -136,6 +136,10 @@ GList *         _clutter_stage_peek_stage_views         (ClutterStage *stage);
 
 int             clutter_stage_get_sync_delay            (ClutterStage *stage);
 
+void            clutter_stage_get_frame_times           (ClutterStage *stage,
+                                                         double       *paint_time,
+                                                         double       *layout_time);
+
 G_END_DECLS
 
 #endif /* __CLUTTER_STAGE_PRIVATE_H__ */

clutter/clutter/clutter-stage.c

@@ -5099,3 +5099,12 @@ _clutter_stage_get_max_view_scale_factor_for_rect (ClutterStage *stage,
   *view_scale = scale;
   return TRUE;
 }
+
+void
+clutter_stage_get_frame_times (ClutterStage *stage,
+                               double       *paint_time,
+                               double       *layout_time)
+{
+  *paint_time = stage->priv->last_paint_time;
+  *layout_time = stage->priv->last_layout_time;
+}

clutter/clutter/cogl/clutter-stage-cogl.c

@@ -405,6 +405,215 @@ paint_damage_region (ClutterStageWindow    *stage_window,
   cogl_framebuffer_pop_matrix (framebuffer);
 }
 
+#define CHART_COLUMN_WIDTH 6 //px
+#define THRESHOLD_LINE_HEIGHT 2 //px
+#define MAX_FRAME_TIME_INFO_ENTRIES 1000
+
+typedef struct
+{
+  double layout_time;
+  double paint_time;
+} FrameTimeInfo;
+
+static void
+get_frame_time_chart_region (ClutterStageWindow    *stage_window,
+                             ClutterStageView      *view,
+                             cairo_rectangle_int_t *region)
+{
+  ClutterStageCogl *stage_cogl = CLUTTER_STAGE_COGL (stage_window);
+  cairo_rectangle_int_t painted_region;
+  cairo_rectangle_int_t layout;
+  double refresh_rate_bar_height;
+  double ms_per_frame;
+  float green_line_y;
+  int sync_delay;
+  int n_points;
+  int i;
+
+  clutter_stage_view_get_layout (view, &layout);
+
+  painted_region = (cairo_rectangle_int_t) {
+    .x = layout.x,
+    .y = layout.y + layout.height,
+    .width = layout.width,
+    .height = 0,
+  };
+
+  n_points = layout.width / CHART_COLUMN_WIDTH;
+
+  /* Chart */
+  sync_delay = clutter_stage_get_sync_delay (stage_cogl->wrapper);
+  ms_per_frame = 1000.0 / stage_cogl->refresh_rate - sync_delay;
+  refresh_rate_bar_height = layout.height * 0.1;
+
+  for (i = 0; i < MIN (stage_cogl->frame_times->len, n_points); i++)
+    {
+      int element = stage_cogl->frame_times->len - i - 1;
+      FrameTimeInfo *info = &g_array_index (stage_cogl->frame_times, FrameTimeInfo, element);
+      double layout_bar_height;
+      double paint_bar_height;
+
+      /* Layout time section */
+      layout_bar_height =
+        info->layout_time / ms_per_frame * refresh_rate_bar_height;
+
+      /* Paint time section */
+      paint_bar_height =
+        info->paint_time / ms_per_frame * refresh_rate_bar_height;
+
+      painted_region.height = MAX (painted_region.height,
+                                   paint_bar_height + layout_bar_height);
+    }
+
+  /* Green line (16.667ms) */
+  green_line_y = layout.height * 0.9;
+
+  painted_region.height = MAX (painted_region.height, green_line_y);
+
+  /* Update the swap region rectangle */
+  painted_region.y -= MIN (layout.height, painted_region.height);
+
+  _clutter_util_rectangle_union (region, &painted_region, region);
+}
+
+static void
+paint_frame_time_chart (ClutterStageWindow *stage_window,
+                        ClutterStageView   *view)
+{
+  CoglFramebuffer *framebuffer = clutter_stage_view_get_onscreen (view);
+  CoglContext *ctx = cogl_framebuffer_get_context (framebuffer);
+  ClutterStageCogl *stage_cogl = CLUTTER_STAGE_COGL (stage_window);
+  ClutterActor *actor = CLUTTER_ACTOR (stage_cogl->wrapper);
+  cairo_rectangle_int_t layout;
+  static CoglPipeline *threshold_pipeline = NULL;
+  static CoglPipeline *paint_time_pipeline = NULL;
+  static CoglPipeline *layout_time_pipeline = NULL;
+  CoglMatrix modelview;
+  double refresh_rate_bar_height;
+  double ms_per_frame;
+  float green_line_y;
+  int sync_delay;
+  int n_points;
+  int i;
+
+  if (G_UNLIKELY (paint_time_pipeline == NULL))
+    {
+      paint_time_pipeline = cogl_pipeline_new (ctx);
+      cogl_pipeline_set_color4ub (paint_time_pipeline, 0x00, 0x00, 0x60, 0xa0);
+    }
+
+  if (G_UNLIKELY (layout_time_pipeline == NULL))
+    {
+      layout_time_pipeline = cogl_pipeline_new (ctx);
+      cogl_pipeline_set_color4ub (layout_time_pipeline, 0x00, 0x60, 0x00, 0xa0);
+    }
+
+  if (G_UNLIKELY (threshold_pipeline == NULL))
+    {
+      threshold_pipeline = cogl_pipeline_new (ctx);
+      cogl_pipeline_set_color4ub (threshold_pipeline, 0x40,  0x00, 0x00, 0x80);
+    }
+
+  cogl_framebuffer_push_matrix (framebuffer);
+  cogl_matrix_init_identity (&modelview);
+  _clutter_actor_apply_modelview_transform (actor, &modelview);
+  cogl_framebuffer_set_modelview_matrix (framebuffer, &modelview);
+
+  clutter_stage_view_get_layout (view, &layout);
+
+  n_points = layout.width / CHART_COLUMN_WIDTH;
+
+  /* Chart */
+  sync_delay = clutter_stage_get_sync_delay (stage_cogl->wrapper);
+  ms_per_frame = 1000.0 / stage_cogl->refresh_rate - sync_delay;
+  refresh_rate_bar_height = layout.height * 0.1;
+
+  for (i = 0; i < MIN (stage_cogl->frame_times->len, n_points); i++)
+    {
+      int element = stage_cogl->frame_times->len - i - 1;
+      FrameTimeInfo *info = &g_array_index (stage_cogl->frame_times, FrameTimeInfo, element);
+      double x_1 = layout.width - (i + 1) * CHART_COLUMN_WIDTH;
+      double x_2 = layout.width - i * CHART_COLUMN_WIDTH;
+      double layout_bar_height;
+      double paint_bar_height;
+
+      /* Layout time section */
+      layout_bar_height =
+        info->layout_time / ms_per_frame * refresh_rate_bar_height;
+      cogl_framebuffer_draw_rectangle (framebuffer,
+                                       layout_time_pipeline,
+                                       x_1,
+                                       layout.height - layout_bar_height,
+                                       x_2,
+                                       layout.height);
+
+      /* Paint time section */
+      paint_bar_height =
+        info->paint_time / ms_per_frame * refresh_rate_bar_height;
+      cogl_framebuffer_draw_rectangle (framebuffer,
+                                       paint_time_pipeline,
+                                       x_1,
+                                       layout.height - paint_bar_height - layout_bar_height,
+                                       x_2,
+                                       layout.height - layout_bar_height);
+    }
+
+  /* Green line (16.667ms) */
+  green_line_y = layout.height * 0.9;
+  cogl_framebuffer_draw_rectangle (framebuffer,
+                                   threshold_pipeline,
+                                   0.0f,
+                                   green_line_y,
+                                   layout.width,
+                                   green_line_y + THRESHOLD_LINE_HEIGHT);
+
+  cogl_framebuffer_pop_matrix (framebuffer);
+}
+
+static inline void
+append_frame_time_info (ClutterStageCogl *stage_cogl)
+{
+  FrameTimeInfo previous_frame_info;
+
+  if (G_LIKELY (!(clutter_paint_debug_flags & CLUTTER_DEBUG_PAINT_FRAME_TIME)))
+    return;
+
+  if (G_UNLIKELY (stage_cogl->frame_times == NULL))
+    stage_cogl->frame_times = g_array_sized_new (FALSE, TRUE,
+                                                 sizeof (FrameTimeInfo),
+                                                 MAX_FRAME_TIME_INFO_ENTRIES);
+
+  clutter_stage_get_frame_times (stage_cogl->wrapper,
+                                 &previous_frame_info.paint_time,
+                                 &previous_frame_info.layout_time);
+
+  g_array_append_val (stage_cogl->frame_times, previous_frame_info);
+
+  if (stage_cogl->frame_times->len > MAX_FRAME_TIME_INFO_ENTRIES)
+    g_array_remove_range (stage_cogl->frame_times, 0,
+                          stage_cogl->frame_times->len - MAX_FRAME_TIME_INFO_ENTRIES);
+
+}
+
+static inline void
+maybe_paint_frame_times (ClutterStageWindow *stage_window,
+                         ClutterStageView   *view)
+{
+  ClutterStageCogl *stage_cogl = CLUTTER_STAGE_COGL (stage_window);
+
+  if (G_UNLIKELY ((clutter_paint_debug_flags & CLUTTER_DEBUG_PAINT_FRAME_TIME)))
+    {
+      paint_frame_time_chart (stage_window, view);
+      stage_cogl->painting_frame_chart = TRUE;
+    }
+  else if (stage_cogl->painting_frame_chart)
+    {
+      g_array_free (stage_cogl->frame_times, TRUE);
+      stage_cogl->frame_times = NULL;
+      stage_cogl->painting_frame_chart = FALSE;
+    }
+}
+
 static gboolean
 swap_framebuffer (ClutterStageWindow    *stage_window,
                   ClutterStageView      *view,
@@ -672,6 +881,9 @@ clutter_stage_cogl_redraw_view (ClutterStageWindow *stage_window,
       fb_clip_region = (cairo_rectangle_int_t) { 0 };
     }
 
+  if (G_UNLIKELY ((clutter_paint_debug_flags & CLUTTER_DEBUG_PAINT_FRAME_TIME)))
+    get_frame_time_chart_region (stage_window, view, &fb_clip_region);
+
   if (may_use_clipped_redraw &&
       G_LIKELY (!(clutter_paint_debug_flags & CLUTTER_DEBUG_DISABLE_CLIPPED_REDRAWS)))
     use_clipped_redraw = TRUE;
@@ -827,6 +1039,9 @@ clutter_stage_cogl_redraw_view (ClutterStageWindow *stage_window,
       else
         paint_stage (stage_cogl, view, &view_rect);
     }
+
+  maybe_paint_frame_times (stage_window, view);
+
   cogl_pop_framebuffer ();
 
   if (may_use_clipped_redraw &&
@@ -931,6 +1146,8 @@ clutter_stage_cogl_redraw (ClutterStageWindow *stage_window)
   gboolean swap_event = FALSE;
   GList *l;
 
+  append_frame_time_info (stage_cogl);
+
   for (l = _clutter_stage_window_get_views (stage_window); l; l = l->next)
     {
       ClutterStageView *view = l->data;

clutter/clutter/cogl/clutter-stage-cogl.h

@@ -66,6 +66,9 @@ struct _ClutterStageCogl
   /* TRUE if the current paint cycle has a clipped redraw. In that
      case bounding_redraw_clip specifies the the bounds. */
   guint using_clipped_redraw : 1;
+
+  gboolean painting_frame_chart;
+  GArray *frame_times;
 };
 
 struct _ClutterStageCoglClass