Reduce unnecessary background changes via `IEquatable` implementation

osu.Game/Graphics/Backgrounds/Background.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -14,7 +15,7 @@ namespace osu.Game.Graphics.Backgrounds
     /// <summary>
     /// A background which offers blurring via a <see cref="BufferedContainer"/> on demand.
     /// </summary>
-    public class Background : CompositeDrawable
+    public class Background : CompositeDrawable, IEquatable<Background>
     {
         private const float blur_scale = 0.5f;
 
@@ -71,5 +72,14 @@ public void BlurTo(Vector2 newBlurSigma, double duration = 0, Easing easing = Ea
 
             bufferedContainer?.BlurTo(newBlurSigma * blur_scale, duration, easing);
         }
+
+        public virtual bool Equals(Background other)
+        {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+
+            return other.GetType() == GetType()
+                   && other.textureName == textureName;
+        }
     }
 }

osu.Game/Graphics/Backgrounds/BeatmapBackground.cs

@@ -24,5 +24,14 @@ private void load(LargeTextureStore textures)
         {
             Sprite.Texture = Beatmap?.Background ?? textures.Get(fallbackTextureName);
         }
+
+        public override bool Equals(Background other)
+        {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+
+            return other.GetType() == GetType()
+                   && ((BeatmapBackground)other).Beatmap == Beatmap;
+        }
     }
 }

osu.Game/Graphics/Backgrounds/SkinBackground.cs

@@ -21,5 +21,14 @@ private void load()
         {
             Sprite.Texture = skin.GetTexture("menu-background") ?? Sprite.Texture;
         }
+
+        public override bool Equals(Background other)
+        {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+
+            return other.GetType() == GetType()
+                   && ((SkinBackground)other).skin.SkinInfo.Equals(skin.SkinInfo);
+        }
     }
 }

osu.Game/Screens/Backgrounds/BackgroundScreenDefault.cs

@@ -112,12 +112,6 @@ private Background createBackground()
                             newBackground = new BeatmapBackgroundWithStoryboard(beatmap.Value, getBackgroundTextureName());
                         newBackground ??= new BeatmapBackground(beatmap.Value, getBackgroundTextureName());
 
-                        // this method is called in many cases where the beatmap hasn't changed (ie. on screen transitions).
-                        // if a background is already displayed for the requested beatmap, we don't want to load it again.
-                        if (background?.GetType() == newBackground.GetType() &&
-                            (background as BeatmapBackground)?.Beatmap == beatmap.Value)
-                            return background;
-
                         break;
                     }
 
@@ -127,6 +121,11 @@ private Background createBackground()
                 }
             }
 
+            // this method is called in many cases where the background might not necessarily need to change.
+            // if an equivalent background is currently being shown, we don't want to load it again.
+            if (newBackground?.Equals(background) == true)
+                return background;
+
             newBackground ??= new Background(getBackgroundTextureName());
             newBackground.Depth = currentDisplay;