Implement DimmableVideo component

osu.Game/Screens/Play/DimmableVideo.cs

@@ -0,0 +1,64 @@
+// 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 osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Video;
+using osu.Game.Graphics.Containers;
+
+namespace osu.Game.Screens.Play
+{
+    public class DimmableVideo : UserDimContainer
+    {
+        private readonly VideoSprite video;
+        private DrawableVideo drawableVideo;
+
+        public DimmableVideo(VideoSprite video)
+        {
+            this.video = video;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            initializeVideo(false);
+        }
+
+        protected override void LoadComplete()
+        {
+            ShowStoryboard.BindValueChanged(_ => initializeVideo(true), true);
+            base.LoadComplete();
+        }
+
+        protected override bool ShowDimContent => ShowStoryboard.Value && DimLevel < 1;
+
+        private void initializeVideo(bool async)
+        {
+            if (drawableVideo != null)
+                return;
+
+            if (!ShowStoryboard.Value)
+                return;
+
+            drawableVideo = new DrawableVideo(video);
+
+            if (async)
+                LoadComponentAsync(drawableVideo, Add);
+            else
+                Add(drawableVideo);
+        }
+
+        private class DrawableVideo : Container
+        {
+            public DrawableVideo(VideoSprite video)
+            {
+                RelativeSizeAxes = Axes.Both;
+                Masking = true;
+
+                AddInternal(video);
+                video.RelativeSizeAxes = Axes.Both;
+            }
+        }
+    }
+}