Wire up host haptics, hold Fast Forward key to test

DirectInput works, OpenTK 3 doesn't seem to actually support it even though the
method is present and has documentation -_-

src/BizHawk.Bizware.DirectX/DirectInputAdapter.cs

@@ -10,6 +10,10 @@ namespace BizHawk.Bizware.DirectX
 {
 	public sealed class DirectInputAdapter : IHostInputAdapter
 	{
+		private static readonly IReadOnlyCollection<string> XINPUT_HAPTIC_CHANNEL_NAMES = new[] { "Left", "Right" }; // doesn't seem to be a way to detect this via XInput, so assuming x360/xbone will be good enough
+
+		private IReadOnlyDictionary<string, int> _lastHapticsSnapshot = new Dictionary<string, int>();
+
 		private Config? _config;
 
 		public void DeInitAll()
@@ -25,6 +29,9 @@ namespace BizHawk.Bizware.DirectX
 			ReInitGamepads(mainFormHandle);
 		}
 
+		public IReadOnlyDictionary<string, IReadOnlyCollection<string>> GetHapticsChannels()
+			=> GamePad360.EnumerateDevices().ToDictionary(pad => pad.InputNamePrefix, _ => XINPUT_HAPTIC_CHANNEL_NAMES);
+
 		public void ReInitGamepads(IntPtr mainFormHandle)
 		{
 			GamePad.Initialize(mainFormHandle);
@@ -43,6 +50,9 @@ namespace BizHawk.Bizware.DirectX
 			{
 				for (int b = 0, n = pad.NumButtons; b < n; b++) handleButton(pad.InputNamePrefix + pad.ButtonName(b), pad.Pressed(b), ClientInputFocus.Pad);
 				foreach (var (axisName, f) in pad.GetAxes()) handleAxis(pad.InputNamePrefix + axisName, (int) f);
+				_lastHapticsSnapshot.TryGetValue(pad.InputNamePrefix + "Left", out var leftStrength);
+				_lastHapticsSnapshot.TryGetValue(pad.InputNamePrefix + "Right", out var rightStrength);
+				pad.SetVibration(leftStrength, rightStrength); // values will be 0 if not found
 			}
 			foreach (var pad in GamePad.EnumerateDevices())
 			{
@@ -54,6 +64,9 @@ namespace BizHawk.Bizware.DirectX
 		public IEnumerable<KeyEvent> ProcessHostKeyboards() => KeyInput.Update(_config ?? throw new Exception(nameof(ProcessHostKeyboards) + " called before the global config was passed"))
 			.Concat(IPCKeyInput.Update());
 
+		public void SetHaptics(IReadOnlyCollection<(string Name, int Strength)> hapticsSnapshot)
+			=> _lastHapticsSnapshot = hapticsSnapshot.ToDictionary(tuple => tuple.Name, tuple => tuple.Strength);
+
 		public void UpdateConfig(Config config) => _config = config;
 	}
 }

src/BizHawk.Bizware.DirectX/GamePad360.cs

@@ -231,5 +231,12 @@ namespace BizHawk.Bizware.DirectX
 		public string ButtonName(int index) => _names[index];
 
 		public bool Pressed(int index) => _actions[index]();
+
+		/// <remarks><paramref name="left"/> and <paramref name="right"/> are in 0..<see cref="int.MaxValue"/></remarks>
+		public void SetVibration(int left, int right)
+		{
+			static ushort Conv(int i) => unchecked((ushort) ((i >> 15) & 0xFFFF));
+			_controller.SetVibration(new() { LeftMotorSpeed = Conv(left), RightMotorSpeed = Conv(right) });
+		}
 	}
 }

src/BizHawk.Bizware.OpenTK3/OTK_Gamepad.cs

@@ -107,6 +107,8 @@ namespace BizHawk.Bizware.OpenTK3
 		/// <summary>The object returned by <see cref="Joystick.GetCapabilities"/></summary>
 		private readonly JoystickCapabilities? _joystickCapabilities;
 
+		public readonly IReadOnlyCollection<string> HapticsChannels;
+
 		/// <summary>For use in keybind boxes</summary>
 		public readonly string InputNamePrefix;
 
@@ -145,7 +147,9 @@ namespace BizHawk.Bizware.OpenTK3
 			{
 				_name = "OTK GamePad Undetermined Name";
 			}
-
+			HapticsChannels = _gamePadCapabilities != null && _gamePadCapabilities.Value.HasLeftVibrationMotor && _gamePadCapabilities.Value.HasRightVibrationMotor
+				? new[] { "Left", "Right" } // two haptic motors
+				: new[] { "Mono" }; // one or zero haptic motors -- in the latter case, pretend it's mono anyway as that doesn't seem to cause problems
 			InputNamePrefix = $"{(MappedGamePad ? "X" : "J")}{_playerIndex} ";
 
 			Update();
@@ -360,17 +364,13 @@ namespace BizHawk.Bizware.OpenTK3
 			AddItem("RightTrigger", () => state.Triggers.Right > dzt);
 		}
 
-		/// <summary>
-		/// Sets the gamepad's left and right vibration
-		/// We don't currently use this in Bizhawk - do we have any cores that support this?
-		/// </summary>
-		/// <param name="left"></param>
-		/// <param name="right"></param>
-		public void SetVibration(float left, float right) => OpenTKGamePad.SetVibration(
-			_deviceIndex,
-			_gamePadCapabilities?.HasLeftVibrationMotor == true ? left : 0,
-			_gamePadCapabilities?.HasRightVibrationMotor == true ? right : 0
-		);
+		/// <remarks><paramref name="left"/> and <paramref name="right"/> are in 0..<see cref="int.MaxValue"/></remarks>
+		public void SetVibration(int left, int right)
+		{
+			const double SCALE = 1.0 / int.MaxValue;
+			static float Conv(int i) => (float) (i * SCALE);
+			OpenTKGamePad.SetVibration(_deviceIndex, Conv(left), Conv(right));
+		}
 	}
 }
 

src/BizHawk.Bizware.OpenTK3/OpenTKInputAdapter.cs

@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 
 using BizHawk.Client.Common;
 
@@ -9,6 +10,8 @@ namespace BizHawk.Bizware.OpenTK3
 {
 	public sealed class OpenTKInputAdapter : IHostInputAdapter
 	{
+		private IReadOnlyDictionary<string, int> _lastHapticsSnapshot = new Dictionary<string, int>();
+
 		public void DeInitAll() {}
 
 		public void FirstInitAll(IntPtr mainFormHandle)
@@ -17,6 +20,9 @@ namespace BizHawk.Bizware.OpenTK3
 			OTK_GamePad.Initialize();
 		}
 
+		public IReadOnlyDictionary<string, IReadOnlyCollection<string>> GetHapticsChannels()
+			=> OTK_GamePad.EnumerateDevices().ToDictionary(pad => pad.InputNamePrefix, pad => pad.HapticsChannels);
+
 		public void ReInitGamepads(IntPtr mainFormHandle) {}
 
 		public void PreprocessHostGamepads() => OTK_GamePad.UpdateAll();
@@ -27,11 +33,42 @@ namespace BizHawk.Bizware.OpenTK3
 			{
 				foreach (var but in pad.buttonObjects) handleButton(pad.InputNamePrefix + but.ButtonName, but.ButtonAction(), ClientInputFocus.Pad);
 				foreach (var (axisID, f) in pad.GetAxes()) handleAxis($"{pad.InputNamePrefix}{axisID} Axis", (int) f);
+#if DEBUG // effectively no-op as OpenTK 3 doesn't seem to actually support haptic feedback
+				foreach (var channel in pad.HapticsChannels)
+				{
+					if (!_lastHapticsSnapshot.TryGetValue(pad.InputNamePrefix + channel, out var strength))
+					{
+						pad.SetVibration(0, 0);
+						continue;
+					}
+					switch (channel)
+					{
+						case "Mono":
+							pad.SetVibration(strength, strength);
+							break;
+						case "Left": // presence of left channel implies presence of right channel, so we'll use it here...
+							pad.SetVibration(strength, _lastHapticsSnapshot[pad.InputNamePrefix + "Right"]);
+							break;
+						case "Right": // ...and ignore it here
+							break;
+						default:
+							Console.WriteLine(nameof(OTK_GamePad) + " has a new kind of haptic channel? (Dev forgot to update this file too?)");
+							break;
+					}
+				}
+#endif
 			}
 		}
 
 		public IEnumerable<KeyEvent> ProcessHostKeyboards() => OTK_Keyboard.Update();
 
+		public void SetHaptics(IReadOnlyCollection<(string Name, int Strength)> hapticsSnapshot)
+#if DEBUG // effectively no-op as OpenTK 3 doesn't seem to actually support haptic feedback
+			=> _lastHapticsSnapshot = hapticsSnapshot.ToDictionary(tuple => tuple.Name, tuple => tuple.Strength);
+#else
+		{}
+#endif
+
 		public void UpdateConfig(Config config) {}
 	}
 }

src/BizHawk.Client.Common/controllers/SimpleController.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 
 using BizHawk.Common;
 using BizHawk.Emulation.Common;
@@ -14,11 +15,13 @@ namespace BizHawk.Client.Common
 
 		protected WorkingDictionary<string, bool> Buttons { get; private set; } = new WorkingDictionary<string, bool>();
 		protected WorkingDictionary<string, int> Axes { get; private set; } = new WorkingDictionary<string, int>();
+		protected WorkingDictionary<string, int> HapticFeedback { get; private set; } = new WorkingDictionary<string, int>();
 
 		public void Clear()
 		{
 			Buttons = new WorkingDictionary<string, bool>();
 			Axes = new WorkingDictionary<string, int>();
+			HapticFeedback = new WorkingDictionary<string, int>();
 		}
 
 		public bool this[string button]
@@ -31,6 +34,11 @@ namespace BizHawk.Client.Common
 
 		public int AxisValue(string name) => Axes[name];
 
+		public IReadOnlyCollection<(string Name, int Strength)> GetHapticsSnapshot()
+			=> HapticFeedback.Select(kvp => (kvp.Key, kvp.Value)).ToArray();
+
+		public void SetHapticChannelStrength(string name, int strength) => HapticFeedback[name] = strength;
+
 		public IDictionary<string, bool> BoolButtons() => Buttons;
 
 		public void AcceptNewAxis(string axisId, int value)

src/BizHawk.Client.Common/input/HostInputAdapter.cs

@@ -12,6 +12,9 @@ namespace BizHawk.Client.Common
 
 		void FirstInitAll(IntPtr mainFormHandle);
 
+		/// <remarks>keys are pad prefixes "X# "/"J# " (with the trailing space)</remarks>
+		IReadOnlyDictionary<string, IReadOnlyCollection<string>> GetHapticsChannels();
+
 		void ReInitGamepads(IntPtr mainFormHandle);
 
 		void PreprocessHostGamepads();
@@ -20,6 +23,9 @@ namespace BizHawk.Client.Common
 
 		IEnumerable<KeyEvent> ProcessHostKeyboards();
 
+		/// <remarks>implementors may store this for use during the next <see cref="ProcessHostGamepads"/> call</remarks>
+		void SetHaptics(IReadOnlyCollection<(string Name, int Strength)> hapticsSnapshot);
+
 		void UpdateConfig(Config config);
 	}
 }

src/BizHawk.Client.EmuHawk/MainForm.cs

@@ -310,7 +310,6 @@ namespace BizHawk.Client.EmuHawk
 
 			InputManager = new InputManager
 			{
-				ControllerInputCoalescer = new ControllerInputCoalescer(),
 				GetMainFormMouseInfo = () =>
 				{
 					var b = Control.MouseButtons;
@@ -669,6 +668,14 @@ namespace BizHawk.Client.EmuHawk
 
 		public override bool BlocksInputWhenFocused { get; } = false;
 
+		private static readonly IReadOnlyCollection<string> DEBUG_HAPTIC_CHANNELS = new[]
+		{
+			"J0 Mono", "J0 Left", "J0 Right",
+			"X0 Mono", "X0 Left", "X0 Right",
+			"J1 Mono", "J1 Left", "J1 Right",
+			"X1 Mono", "X1 Left", "X1 Right"
+		};
+
 		public int ProgramRunLoop()
 		{
 			// needs to be done late, after the log console snaps on top
@@ -701,7 +708,11 @@ namespace BizHawk.Client.EmuHawk
 				Input.Instance.Update();
 
 				// handle events and dispatch as a hotkey action, or a hotkey button, or an input button
+				// ...but prepare haptics first, those get read in ProcessInput
 				var finalHostController = (ControllerInputCoalescer) InputManager.ControllerInputCoalescer;
+				// for now, vibrate the first gamepad when the Fast Forward hotkey is held, using the value from the previous (host) frame
+				var debugVibrating = InputManager.ClientControls.IsPressed("Fast Forward") ? int.MaxValue : 0;
+				foreach (var channel in DEBUG_HAPTIC_CHANNELS) finalHostController.SetHapticChannelStrength(channel, debugVibrating);
 				ProcessInput(
 					_hotkeyCoalescer,
 					finalHostController,
@@ -976,6 +987,8 @@ namespace BizHawk.Client.EmuHawk
 			Func<string, List<string>> searchHotkeyBindings,
 			Func<string, bool> activeControllerHasBinding)
 		{
+			Input.Instance.Adapter.SetHaptics(finalHostController.GetHapticsSnapshot());
+
 			// loop through all available events
 			Input.InputEvent ie;
 			while ((ie = Input.Instance.DequeueEvent()) != null)
@@ -2053,6 +2066,7 @@ namespace BizHawk.Client.EmuHawk
 			}
 
 			InputManager.ClientControls = controls;
+			InputManager.ControllerInputCoalescer = new ControllerInputCoalescer(); // ctor initialises values for host haptics
 			_autofireNullControls = new AutofireController(
 				Emulator,
 				Config.AutofireOn,