[mutter/wip/carlosg/drop-no-clear-hint: 2/2] clutter: Drop the no-clear stage hint

[Carlos Garnacho <carlosg src gnome org>]

commit 77bc1ea5096e06e38f0a5fcda359e084ec419b05
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Nov 1 12:05:32 2019 +0100

    clutter: Drop the no-clear stage hint
    
    A compositor is notably opaque (usually has nothing to be painted on!).
    gnome-shell sets this hint, but there's no reason why we wouldn't want
    it by default.
    
    Also, the color buffer being cleared messes with stencil clips, as the
    clear operation by definition ignores the stencil buffer. We want to
    use these more extensively in the future, so just drop this API.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/911

 clutter/clutter/clutter-actor.c |   2 -
 clutter/clutter/clutter-stage.c | 117 ----------------------------------------
 clutter/clutter/clutter-stage.h |   5 --
 3 files changed, 124 deletions(-)
---
diff --git a/clutter/clutter/clutter-actor.c b/clutter/clutter/clutter-actor.c
index ac2e54afd..af9353e0e 100644
--- a/clutter/clutter/clutter-actor.c
+++ b/clutter/clutter/clutter-actor.c
@@ -3807,8 +3807,6 @@ clutter_actor_paint_node (ClutterActor     *actor,
                     bg_color.alpha);
 
       clear_flags = COGL_BUFFER_BIT_DEPTH;
-      if (!clutter_stage_get_no_clear_hint (CLUTTER_STAGE (actor)))
-        clear_flags |= COGL_BUFFER_BIT_COLOR;
 
       node = clutter_root_node_new (fb, &bg_color, clear_flags);
       clutter_paint_node_set_name (node, "stageClear");
diff --git a/clutter/clutter/clutter-stage.c b/clutter/clutter/clutter-stage.c
index f1f75bd0a..4b6f46612 100644
--- a/clutter/clutter/clutter-stage.c
+++ b/clutter/clutter/clutter-stage.c
@@ -78,24 +78,6 @@
 #include "cogl/cogl.h"
 #include "cogl/cogl-trace.h"
 
-/* <private>
- * ClutterStageHint:
- * @CLUTTER_STAGE_NONE: No hint set
- * @CLUTTER_STAGE_NO_CLEAR_ON_PAINT: When this hint is set, the stage
- *   should not clear the viewport; this flag is useful when painting
- *   fully opaque actors covering the whole visible area of the stage,
- *   i.e. when no blending with the stage color happens over the whole
- *   stage viewport
- */
-typedef enum /*< prefix=CLUTTER_STAGE >*/
-{
-  CLUTTER_STAGE_HINT_NONE = 0,
-
-  CLUTTER_STAGE_NO_CLEAR_ON_PAINT = 1 << 0
-} ClutterStageHint;
-
-#define STAGE_NO_CLEAR_ON_PAINT(s)      ((((ClutterStage *) (s))->priv->stage_hints & 
CLUTTER_STAGE_NO_CLEAR_ON_PAINT) != 0)
-
 struct _ClutterStageQueueRedrawEntry
 {
   ClutterActor *actor;
@@ -132,8 +114,6 @@ struct _ClutterStagePrivate
 
   GQueue *event_queue;
 
-  ClutterStageHint stage_hints;
-
   GArray *paint_volume_stack;
 
   ClutterPlane current_clip_planes[4];
@@ -188,7 +168,6 @@ enum
   PROP_TITLE,
   PROP_USE_ALPHA,
   PROP_KEY_FOCUS,
-  PROP_NO_CLEAR_HINT,
   PROP_ACCEPT_FOCUS,
   PROP_LAST
 };
@@ -1889,10 +1868,6 @@ clutter_stage_set_property (GObject      *object,
       clutter_stage_set_key_focus (stage, g_value_get_object (value));
       break;
 
-    case PROP_NO_CLEAR_HINT:
-      clutter_stage_set_no_clear_hint (stage, g_value_get_boolean (value));
-      break;
-
     case PROP_ACCEPT_FOCUS:
       clutter_stage_set_accept_focus (stage, g_value_get_boolean (value));
       break;
@@ -1943,15 +1918,6 @@ clutter_stage_get_property (GObject    *gobject,
       g_value_set_object (value, priv->key_focused_actor);
       break;
 
-    case PROP_NO_CLEAR_HINT:
-      {
-        gboolean hint =
-          (priv->stage_hints & CLUTTER_STAGE_NO_CLEAR_ON_PAINT) != 0;
-
-        g_value_set_boolean (value, hint);
-      }
-      break;
-
     case PROP_ACCEPT_FOCUS:
       g_value_set_boolean (value, priv->accept_focus);
       break;
@@ -2154,23 +2120,6 @@ clutter_stage_class_init (ClutterStageClass *klass)
                            CLUTTER_TYPE_ACTOR,
                            CLUTTER_PARAM_READWRITE);
 
-  /**
-   * ClutterStage:no-clear-hint:
-   *
-   * Whether or not the #ClutterStage should clear its contents
-   * before each paint cycle.
-   *
-   * See clutter_stage_set_no_clear_hint() for further information.
-   *
-   * Since: 1.4
-   */
-  obj_props[PROP_NO_CLEAR_HINT] =
-      g_param_spec_boolean ("no-clear-hint",
-                            P_("No Clear Hint"),
-                            P_("Whether the stage should clear its contents"),
-                            FALSE,
-                            CLUTTER_PARAM_READWRITE);
-
   /**
    * ClutterStage:accept-focus:
    *
@@ -3788,72 +3737,6 @@ _clutter_stage_clear_update_time (ClutterStage *stage)
     _clutter_stage_window_clear_update_time (stage_window);
 }
 
-/**
- * clutter_stage_set_no_clear_hint:
- * @stage: a #ClutterStage
- * @no_clear: %TRUE if the @stage should not clear itself on every
- *   repaint cycle
- *
- * Sets whether the @stage should clear itself at the beginning
- * of each paint cycle or not.
- *
- * Clearing the #ClutterStage can be a costly operation, especially
- * if the stage is always covered - for instance, in a full-screen
- * video player or in a game with a background texture.
- *
- * This setting is a hint; Clutter might discard this hint
- * depending on its internal state.
- *
- * If parts of the stage are visible and you disable clearing you
- * might end up with visual artifacts while painting the contents of
- * the stage.
- *
- * Since: 1.4
- */
-void
-clutter_stage_set_no_clear_hint (ClutterStage *stage,
-                                 gboolean      no_clear)
-{
-  ClutterStagePrivate *priv;
-  ClutterStageHint new_hints;
-
-  g_return_if_fail (CLUTTER_IS_STAGE (stage));
-
-  priv = stage->priv;
-  new_hints = priv->stage_hints;
-
-  if (no_clear)
-    new_hints |= CLUTTER_STAGE_NO_CLEAR_ON_PAINT;
-  else
-    new_hints &= ~CLUTTER_STAGE_NO_CLEAR_ON_PAINT;
-
-  if (priv->stage_hints == new_hints)
-    return;
-
-  priv->stage_hints = new_hints;
-
-  g_object_notify_by_pspec (G_OBJECT (stage), obj_props[PROP_NO_CLEAR_HINT]);
-}
-
-/**
- * clutter_stage_get_no_clear_hint:
- * @stage: a #ClutterStage
- *
- * Retrieves the hint set with clutter_stage_set_no_clear_hint()
- *
- * Return value: %TRUE if the stage should not clear itself on every paint
- *   cycle, and %FALSE otherwise
- *
- * Since: 1.4
- */
-gboolean
-clutter_stage_get_no_clear_hint (ClutterStage *stage)
-{
-  g_return_val_if_fail (CLUTTER_IS_STAGE (stage), FALSE);
-
-  return (stage->priv->stage_hints & CLUTTER_STAGE_NO_CLEAR_ON_PAINT) != 0;
-}
-
 ClutterPaintVolume *
 _clutter_stage_paint_volume_stack_allocate (ClutterStage *stage)
 {
diff --git a/clutter/clutter/clutter-stage.h b/clutter/clutter/clutter-stage.h
index f40ce8164..88cd96ad5 100644
--- a/clutter/clutter/clutter-stage.h
+++ b/clutter/clutter/clutter-stage.h
@@ -164,11 +164,6 @@ void            clutter_stage_get_minimum_size                  (ClutterStage
                                                                  guint                 *width,
                                                                  guint                 *height);
 CLUTTER_EXPORT
-void            clutter_stage_set_no_clear_hint                 (ClutterStage          *stage,
-                                                                 gboolean               no_clear);
-CLUTTER_EXPORT
-gboolean        clutter_stage_get_no_clear_hint                 (ClutterStage          *stage);
-CLUTTER_EXPORT
 void            clutter_stage_set_use_alpha                     (ClutterStage          *stage,
                                                                  gboolean               use_alpha);
 CLUTTER_EXPORT