3 files changed, 284 insertions, 0 deletions
diff --git a/Ryujinx.Input/Assigner/GamepadButtonAssigner.cs b/Ryujinx.Input/Assigner/GamepadButtonAssigner.cs
new file mode 100644
index 00000000..e3aaf8b1
--- /dev/null
+++ b/Ryujinx.Input/Assigner/GamepadButtonAssigner.cs
@@ -0,0 +1,198 @@
+using System.Collections.Generic;
+using System;
+using System.IO;
+using System.Linq;
+
+namespace Ryujinx.Input.Assigner
+{
+    /// <summary>
+    /// <see cref="IButtonAssigner"/> implementation for regular <see cref="IGamepad"/>.
+    /// </summary>
+    public class GamepadButtonAssigner : IButtonAssigner
+    {
+        private IGamepad _gamepad;
+
+        private GamepadStateSnapshot _currState;
+
+        private GamepadStateSnapshot _prevState;
+
+        private JoystickButtonDetector _detector;
+
+        private bool _forStick;
+
+        public GamepadButtonAssigner(IGamepad gamepad, float triggerThreshold, bool forStick)
+        {
+            _gamepad = gamepad;
+            _detector = new JoystickButtonDetector();
+            _forStick = forStick;
+
+            _gamepad?.SetTriggerThreshold(triggerThreshold);
+        }
+
+        public void Initialize()
+        {
+            if (_gamepad != null)
+            {
+                _currState = _gamepad.GetStateSnapshot();
+                _prevState = _currState;
+            }    
+        }
+
+        public void ReadInput()
+        {
+            if (_gamepad != null)
+            {
+                _prevState = _currState;
+                _currState = _gamepad.GetStateSnapshot();
+            }
+
+            CollectButtonStats();
+        }
+
+        public bool HasAnyButtonPressed()
+        {
+            return _detector.HasAnyButtonPressed();
+        }
+
+        public bool ShouldCancel()
+        {
+            return _gamepad == null || !_gamepad.IsConnected;
+        }
+
+        public string GetPressedButton()
+        {
+            IEnumerable<GamepadButtonInputId> pressedButtons = _detector.GetPressedButtons();
+
+            if (pressedButtons.Any())
+            {
+                return !_forStick ? pressedButtons.First().ToString() : ((StickInputId)pressedButtons.First()).ToString();
+            }
+
+            return "";
+        }
+
+        private void CollectButtonStats()
+        {
+            if (_forStick)
+            {
+                for (StickInputId inputId = StickInputId.Left; inputId < StickInputId.Count; inputId++)
+                {
+                    (float x, float y) = _currState.GetStick(inputId);
+
+                    float value;
+
+                    if (x != 0.0f)
+                    {
+                        value = x;
+                    }
+                    else if (y != 0.0f)
+                    {
+                        value = y;
+                    }
+                    else
+                    {
+                        continue;
+                    }
+
+                    _detector.AddInput((GamepadButtonInputId)inputId, value);
+                }
+            }
+            else
+            {
+                for (GamepadButtonInputId inputId = GamepadButtonInputId.A; inputId < GamepadButtonInputId.Count; inputId++)
+                {
+                    if (_currState.IsPressed(inputId) && !_prevState.IsPressed(inputId))
+                    {
+                        _detector.AddInput(inputId, 1);
+                    }
+
+                    if (!_currState.IsPressed(inputId) && _prevState.IsPressed(inputId))
+                    {
+                        _detector.AddInput(inputId, -1);
+                    }
+                }
+            }
+        }
+
+        private class JoystickButtonDetector
+        {
+            private Dictionary<GamepadButtonInputId, InputSummary> _stats;
+
+            public JoystickButtonDetector()
+            {
+                _stats = new Dictionary<GamepadButtonInputId, InputSummary>();
+            }
+
+            public bool HasAnyButtonPressed()
+            {
+                return _stats.Values.Any(CheckButtonPressed);
+            }
+
+            public IEnumerable<GamepadButtonInputId> GetPressedButtons()
+            {
+                return _stats.Where(kvp => CheckButtonPressed(kvp.Value)).Select(kvp => kvp.Key);
+            }
+
+            public void AddInput(GamepadButtonInputId button, float value)
+            {
+                InputSummary inputSummary;
+
+                if (!_stats.TryGetValue(button, out inputSummary))
+                {
+                    inputSummary = new InputSummary();
+                    _stats.Add(button, inputSummary);
+                }
+
+                inputSummary.AddInput(value);
+            }
+
+            public override string ToString()
+            {
+                StringWriter writer = new StringWriter();
+
+                foreach (var kvp in _stats)
+                {
+                    writer.WriteLine($"Button {kvp.Key} -> {kvp.Value}");
+                }
+
+                return writer.ToString();
+            }
+
+            private bool CheckButtonPressed(InputSummary sequence)
+            {
+                float distance = Math.Abs(sequence.Min - sequence.Avg) + Math.Abs(sequence.Max - sequence.Avg);
+                return distance > 1.5; // distance range [0, 2]
+            }
+        }
+
+        private class InputSummary
+        {
+            public float Min, Max, Sum, Avg;
+
+            public int NumSamples;
+
+            public InputSummary()
+            {
+                Min = float.MaxValue;
+                Max = float.MinValue;
+                Sum = 0;
+                NumSamples = 0;
+                Avg = 0;
+            }
+
+            public void AddInput(float value)
+            {
+                Min = Math.Min(Min, value);
+                Max = Math.Max(Max, value);
+                Sum += value;
+                NumSamples += 1;
+                Avg = Sum / NumSamples;
+            }
+
+            public override string ToString()
+            {
+                return $"Avg: {Avg} Min: {Min} Max: {Max} Sum: {Sum} NumSamples: {NumSamples}";
+            }
+        }
+    }
+}
diff --git a/Ryujinx.Input/Assigner/IButtonAssigner.cs b/Ryujinx.Input/Assigner/IButtonAssigner.cs
new file mode 100644
index 00000000..021736df
--- /dev/null
+++ b/Ryujinx.Input/Assigner/IButtonAssigner.cs
@@ -0,0 +1,36 @@
+namespace Ryujinx.Input.Assigner
+{
+    /// <summary>
+    /// An interface that allows to gather the driver input info to assign to a button on the UI.
+    /// </summary>
+    public interface IButtonAssigner
+    {
+        /// <summary>
+        /// Initialize the button assigner.
+        /// </summary>
+        void Initialize();
+
+        /// <summary>
+        /// Read input.
+        /// </summary>
+        void ReadInput();
+
+        /// <summary>
+        /// Check if a button was pressed.
+        /// </summary>
+        /// <returns>True if a button was pressed</returns>
+        bool HasAnyButtonPressed();
+
+        /// <summary>
+        /// Indicate if the user of this API should cancel operations. This is triggered for example when a gamepad get disconnected or when a user cancel assignation operations.
+        /// </summary>
+        /// <returns>True if the user of this API should cancel operations</returns>
+        bool ShouldCancel();
+
+        /// <summary>
+        /// Get the pressed button that was read in <see cref="ReadInput"/> by the button assigner.
+        /// </summary>
+        /// <returns>The pressed button that was read</returns>
+        string GetPressedButton();
+    }
+}
+\ No newline at end of file
diff --git a/Ryujinx.Input/Assigner/KeyboardKeyAssigner.cs b/Ryujinx.Input/Assigner/KeyboardKeyAssigner.cs
new file mode 100644
index 00000000..23ae3655
--- /dev/null
+++ b/Ryujinx.Input/Assigner/KeyboardKeyAssigner.cs
@@ -0,0 +1,50 @@
+namespace Ryujinx.Input.Assigner
+{
+    /// <summary>
+    /// <see cref="IButtonAssigner"/> implementation for <see cref="IKeyboard"/>.
+    /// </summary>
+    public class KeyboardKeyAssigner : IButtonAssigner
+    {
+        private IKeyboard _keyboard;
+
+        private KeyboardStateSnapshot _keyboardState;
+
+        public KeyboardKeyAssigner(IKeyboard keyboard)
+        {
+            _keyboard = keyboard;
+        }
+
+        public void Initialize() { }
+
+        public void ReadInput()
+        {
+            _keyboardState = _keyboard.GetKeyboardStateSnapshot();
+        }
+
+        public bool HasAnyButtonPressed()
+        {
+            return GetPressedButton().Length != 0;
+        }
+
+        public bool ShouldCancel()
+        {
+            return _keyboardState.IsPressed(Key.Escape);
+        }
+
+        public string GetPressedButton()
+        {
+            string keyPressed = "";
+
+            for (Key key = Key.Unknown; key < Key.Count; key++)
+            {
+                if (_keyboardState.IsPressed(key))
+                {
+                    keyPressed = key.ToString();
+                    break;
+                }
+            }
+
+            return !ShouldCancel() ? keyPressed : "";
+        }
+    }
+}
+\ No newline at end of file