Implement MIDI input support

osu.Framework.Android/AndroidGameHost.cs

@@ -14,6 +14,7 @@
 using osu.Framework.Graphics.Video;
 using osu.Framework.Input;
 using osu.Framework.Input.Handlers;
+using osu.Framework.Input.Handlers.Midi;
 using osu.Framework.IO.Stores;
 using osu.Framework.Platform;
 using osu.Framework.Threading;
@@ -56,7 +57,7 @@ public override ITextInputSource GetTextInput()
             => new AndroidTextInput(gameView);
 
         protected override IEnumerable<InputHandler> CreateAvailableInputHandlers()
-            => new InputHandler[] { new AndroidKeyboardHandler(gameView), new AndroidTouchHandler(gameView) };
+            => new InputHandler[] { new AndroidKeyboardHandler(gameView), new AndroidTouchHandler(gameView), new MidiInputHandler() };
 
         protected override Storage GetStorage(string baseName)
             => new AndroidStorage(baseName, this);

osu.Framework.Tests/Visual/Input/TestSceneMidi.cs

@@ -0,0 +1,103 @@
+// 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.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Input;
+using osu.Framework.Input.Events;
+using osuTK;
+using osuTK.Graphics;
+
+namespace osu.Framework.Tests.Visual.Input
+{
+    public class TestSceneMidi : FrameworkTestScene
+    {
+        public TestSceneMidi()
+        {
+            var keyFlow = new FillFlowContainer
+            {
+                RelativeSizeAxes = Axes.X,
+                AutoSizeAxes = Axes.Y,
+            };
+
+            for (MidiKey k = MidiKey.A0; k < MidiKey.C8; k++)
+                keyFlow.Add(new MidiKeyHandler(k));
+
+            Child = keyFlow;
+        }
+
+        protected override bool OnMidiDown(MidiDownEvent e)
+        {
+            Console.WriteLine(e);
+            return base.OnMidiDown(e);
+        }
+
+        protected override void OnMidiUp(MidiUpEvent e)
+        {
+            Console.WriteLine(e);
+            base.OnMidiUp(e);
+        }
+
+        protected override bool Handle(UIEvent e)
+        {
+            if (!(e is MouseEvent))
+                Console.WriteLine("Event: " + e);
+            return base.Handle(e);
+        }
+
+        private class MidiKeyHandler : CompositeDrawable
+        {
+            private readonly Drawable background;
+
+            public override bool HandleNonPositionalInput => true;
+
+            private readonly MidiKey key;
+
+            public MidiKeyHandler(MidiKey key)
+            {
+                this.key = key;
+
+                Size = new Vector2(50);
+
+                InternalChildren = new[]
+                {
+                    background = new Container
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        Colour = Color4.DarkGreen,
+                        Alpha = 0,
+                        Child = new Box { RelativeSizeAxes = Axes.Both }
+                    },
+                    new SpriteText
+                    {
+                        Anchor = Anchor.Centre,
+                        Origin = Anchor.Centre,
+                        Text = key.ToString().Replace("Sharp", "#")
+                    }
+                };
+            }
+
+            protected override bool OnMidiDown(MidiDownEvent e)
+            {
+                if (e.Key != key)
+                    return base.OnMidiDown(e);
+
+                const float base_opacity = 0.25f; // to make a velocity of 1 not completely invisible
+
+                background.FadeTo(base_opacity + e.Velocity / 128f * (1 - base_opacity), 100, Easing.OutQuint);
+                return true;
+            }
+
+            protected override void OnMidiUp(MidiUpEvent e)
+            {
+                if (e.Key != key)
+                    base.OnMidiUp(e);
+                else
+                    background.FadeOut(100);
+            }
+        }
+    }
+}

osu.Framework.iOS/IOSGameHost.cs

@@ -1,4 +1,4 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// 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;
@@ -13,6 +13,7 @@
 using osu.Framework.Input;
 using osu.Framework.Input.Bindings;
 using osu.Framework.Input.Handlers;
+using osu.Framework.Input.Handlers.Midi;
 using osu.Framework.IO.Stores;
 using osu.Framework.iOS.Graphics.Textures;
 using osu.Framework.iOS.Graphics.Video;
@@ -97,7 +98,7 @@ protected override void PerformExit(bool immediately)
         public override ITextInputSource GetTextInput() => new IOSTextInput(gameView);
 
         protected override IEnumerable<InputHandler> CreateAvailableInputHandlers() =>
-            new InputHandler[] { new IOSTouchHandler(gameView), keyboardHandler = new IOSKeyboardHandler(gameView), rawKeyboardHandler = new IOSRawKeyboardHandler() };
+            new InputHandler[] { new IOSTouchHandler(gameView), keyboardHandler = new IOSKeyboardHandler(gameView), rawKeyboardHandler = new IOSRawKeyboardHandler(), new MidiInputHandler() };
 
         protected override Storage GetStorage(string baseName) => new IOSStorage(baseName, this);
 

osu.Framework/Graphics/Drawable.cs

@@ -2034,6 +2034,13 @@ public bool TriggerEvent(UIEvent e)
                     OnJoystickRelease(joystickRelease);
                     return false;
 
+                case MidiDownEvent midiDown:
+                    return OnMidiDown(midiDown);
+
+                case MidiUpEvent midiUp:
+                    OnMidiUp(midiUp);
+                    return false;
+
                 default:
                     return Handle(e);
             }
@@ -2194,6 +2201,22 @@ public bool TriggerEvent(UIEvent e)
         /// <param name="e">The <see cref="JoystickReleaseEvent"/> containing information about the input event.</param>
         protected virtual void OnJoystickRelease(JoystickReleaseEvent e) => Handle(e);
 
+        /// <summary>
+        /// An event that occurs when a <see cref="MidiKey"/> is pressed.
+        /// </summary>
+        /// <param name="e">The <see cref="MidiDownEvent"/> containing information about the input event.</param>
+        /// <returns>Whether to block the event from propagating to other <see cref="Drawable"/>s in the hierarchy.</returns>
+        protected virtual bool OnMidiDown(MidiDownEvent e) => Handle(e);
+
+        /// <summary>
+        /// An event that occurs when a <see cref="MidiKey"/> is released.
+        /// </summary>
+        /// <remarks>
+        /// This is guaranteed to be invoked if <see cref="MidiDownEvent"/> was invoked.
+        /// </remarks>
+        /// <param name="e">The <see cref="MidiUpEvent"/> containing information about the input event.</param>
+        protected virtual void OnMidiUp(MidiUpEvent e) => Handle(e);
+
         #endregion
 
         /// <summary>