[mutter/gnome-3-36] surface-actor: Simplify culling logic

[Robert Mader <rmader src gnome org>]

commit e120c8eb0c9259743395200ef36c663eeedccc7f
Author: Robert Mader <robert mader posteo de>
Date:   Thu Oct 1 01:38:16 2020 +0200

    surface-actor: Simplify culling logic
    
    This reverts the commits 372d73e2757 and 1d2004524728 - the special
    case for alpha-less textures could only happen on Wayland, but now
    the opaque region is also set in those cases.
    
    This commit saves us some allocations, simplifies the logic a bit and
    makes sure culling uses the same opaque region as our painting paths.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1463
    
    (cherry picked from commit 78592cbcc86e78070eac978403d80ae5ec9089c8)

 src/compositor/meta-surface-actor.c | 21 ++-------------------
 1 file changed, 2 insertions(+), 19 deletions(-)
---
diff --git a/src/compositor/meta-surface-actor.c b/src/compositor/meta-surface-actor.c
index 050c98211e..6cc3a67956 100644
--- a/src/compositor/meta-surface-actor.c
+++ b/src/compositor/meta-surface-actor.c
@@ -301,25 +301,9 @@ meta_surface_actor_cull_out (MetaCullable   *cullable,
       cairo_region_t *scaled_opaque_region;
 
       opaque_region = meta_shaped_texture_get_opaque_region (priv->texture);
-      if (opaque_region)
-        {
-          cairo_region_reference (opaque_region);
-        }
-      else if (meta_shaped_texture_is_opaque (priv->texture))
-        {
-          cairo_rectangle_int_t rect;
-
-          rect = (cairo_rectangle_int_t) {
-            .width = meta_shaped_texture_get_width (priv->texture),
-            .height = meta_shaped_texture_get_height (priv->texture)
-          };
 
-          opaque_region = cairo_region_create_rectangle (&rect);
-        }
-      else
-        {
-          return;
-        }
+      if (!opaque_region)
+        return;
 
       scaled_opaque_region = get_scaled_region (surface_actor,
                                                 opaque_region,
@@ -330,7 +314,6 @@ meta_surface_actor_cull_out (MetaCullable   *cullable,
       if (clip_region)
         cairo_region_subtract (clip_region, scaled_opaque_region);
 
-      cairo_region_destroy (opaque_region);
       cairo_region_destroy (scaled_opaque_region);
     }
 }