[mutter] surface-actor-wayland: Optimize get_current_primary_view for single view

[Marge Bot <marge-bot src gnome org>]

commit 3b7137cb3595ebf78491966f6ee1037ba9e9b6e1
Author: Robert Mader <robert mader posteo de>
Date:   Mon Nov 23 01:32:32 2020 +0100

    surface-actor-wayland: Optimize get_current_primary_view for single view
    
    In case we only have a single view (or there's only one view left to
    check and the actor is visible on previous views) we can take a short-
    cut, saving a region allocation and some calculations.
    
    While on it, declare float numbers in '.f' style to make them more
    recognizable.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1596>

 src/compositor/meta-surface-actor-wayland.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)
---
diff --git a/src/compositor/meta-surface-actor-wayland.c b/src/compositor/meta-surface-actor-wayland.c
index 08b4f79f76..eba68fe496 100644
--- a/src/compositor/meta-surface-actor-wayland.c
+++ b/src/compositor/meta-surface-actor-wayland.c
@@ -88,15 +88,15 @@ meta_surface_actor_wayland_get_current_primary_view (MetaSurfaceActor *actor,
                                                      ClutterStage     *stage)
 {
   ClutterStageView *current_primary_view = NULL;
-  float highest_refresh_rate = 0;
-  float biggest_unobscurred_fraction = 0;
+  float highest_refresh_rate = 0.f;
+  float biggest_unobscurred_fraction = 0.f;
   GList *l;
 
   for (l = clutter_stage_peek_stage_views (stage); l; l = l->next)
     {
       ClutterStageView *stage_view = l->data;
       float refresh_rate;
-      float unobscurred_fraction = 1.0;
+      float unobscurred_fraction = 1.f;
 
       if (clutter_actor_has_mapped_clones (CLUTTER_ACTOR (actor)))
         {
@@ -106,10 +106,18 @@ meta_surface_actor_wayland_get_current_primary_view (MetaSurfaceActor *actor,
         }
       else
         {
-          if (meta_surface_actor_is_obscured_on_stage_view (actor,
-                                                            stage_view,
-                                                            &unobscurred_fraction))
-            continue;
+          if (l->next || biggest_unobscurred_fraction > 0.f)
+            {
+              if (meta_surface_actor_is_obscured_on_stage_view (actor,
+                                                                stage_view,
+                                                                &unobscurred_fraction))
+                continue;
+            }
+          else
+            {
+              if (meta_surface_actor_is_obscured (actor))
+                continue;
+            }
         }
 
       refresh_rate = clutter_stage_view_get_refresh_rate (stage_view);