Add basic button design and footer button addition flow

osu.Game.Tests/Visual/SongSelect/TestSceneSongSelectFooterV2.cs

@@ -19,6 +19,8 @@ namespace osu.Game.Tests.Visual.SongSelect
                 Anchor = Anchor.Centre,
                 Origin = Anchor.Centre
             };
+
+            footer.AddButton(new FooterButtonV2());
         });
 
         [Test]

osu.Game/Screens/Select/FooterV2/FooterButtonV2.cs

@@ -0,0 +1,65 @@
+// 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;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Input.Bindings;
+using osu.Framework.Input.Events;
+using osu.Game.Graphics.Containers;
+using osu.Game.Input.Bindings;
+using osu.Game.Overlays;
+using osuTK;
+
+namespace osu.Game.Screens.Select.FooterV2
+{
+    public partial class FooterButtonV2 : OsuClickableContainer, IKeyBindingHandler<GlobalAction>
+    {
+        private const int button_height = 120;
+        private const int button_width = 140;
+        private const int corner_radius = 10;
+
+        public const float SHEAR_WIDTH = 16;
+
+        [Cached]
+        private OverlayColourProvider colourProvider = new OverlayColourProvider(OverlayColourScheme.Aquamarine);
+
+        protected static readonly Vector2 SHEAR = new Vector2(SHEAR_WIDTH / button_height, 0);
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            Shear = SHEAR;
+            Size = new Vector2(button_width, button_height);
+            Masking = true;
+            CornerRadius = corner_radius;
+            InternalChildren = new Drawable[]
+            {
+                new Box
+                {
+                    Colour = colourProvider.Background3,
+                    RelativeSizeAxes = Axes.Both
+                },
+
+                //For elements that should not be sheared.
+                new Container
+                {
+                    Shear = -SHEAR
+                }
+            };
+        }
+
+        public Action Hovered = null!;
+        public Action HoverLost = null!;
+        public GlobalAction? Hotkey;
+
+        public bool OnPressed(KeyBindingPressEvent<GlobalAction> e)
+        {
+            return false;
+        }
+
+        public void OnReleased(KeyBindingReleaseEvent<GlobalAction> e) { }
+    }
+}

osu.Game/Screens/Select/FooterV2/FooterV2.cs

@@ -1,12 +1,15 @@
 // 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.Collections.Generic;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
 using osu.Framework.Input.Events;
 using osu.Game.Graphics;
+using osu.Game.Graphics.UserInterface;
+using osuTK;
 
 namespace osu.Game.Screens.Select.FooterV2
 {
@@ -14,6 +17,33 @@ namespace osu.Game.Screens.Select.FooterV2
     {
         //Should be 60, setting to 50 for now for the sake of matching the current BackButton height.
         private const int height = 50;
+        private const int padding = 80;
+
+        private readonly List<OverlayContainer> overlays = new List<OverlayContainer>();
+
+        public void AddButton(FooterButtonV2 button, OverlayContainer? overlay = null)
+        {
+            if (overlay != null)
+            {
+                overlays.Add(overlay);
+                button.Action = () => showOverlay(overlay);
+            }
+
+            buttons.Add(button);
+        }
+
+        private void showOverlay(OverlayContainer overlay)
+        {
+            foreach (var o in overlays)
+            {
+                if (o == overlay)
+                    o.ToggleVisibility();
+                else
+                    o.Hide();
+            }
+        }
+
+        private FillFlowContainer<FooterButtonV2> buttons = null!;
 
         [BackgroundDependencyLoader]
         private void load(OsuColour colour)
@@ -26,6 +56,27 @@ namespace osu.Game.Screens.Select.FooterV2
                 {
                     RelativeSizeAxes = Axes.Both,
                     Colour = colour.B5
+                },
+                new FillFlowContainer
+                {
+                    Anchor = Anchor.BottomLeft,
+                    Origin = Anchor.BottomLeft,
+                    Position = new Vector2(TwoLayerButton.SIZE_EXTENDED.X + padding, 40),
+                    RelativeSizeAxes = Axes.Y,
+                    AutoSizeAxes = Axes.X,
+                    Direction = FillDirection.Horizontal,
+                    Spacing = new Vector2(padding, 0),
+                    Children = new Drawable[]
+                    {
+                        buttons = new FillFlowContainer<FooterButtonV2>
+                        {
+                            Anchor = Anchor.BottomLeft,
+                            Origin = Anchor.BottomLeft,
+                            Direction = FillDirection.Horizontal,
+                            Spacing = new Vector2(-FooterButtonV2.SHEAR_WIDTH, 5),
+                            AutoSizeAxes = Axes.Both
+                        }
+                    }
                 }
             };
         }