blittable button identifiers

src/Input/ButtonIdentifier.cs

@@ -0,0 +1,31 @@
+namespace MoonWorks.Input
+{
+    // Blittable identifier that can be used for button state lookups.
+    public struct ButtonIdentifier
+    {
+        public DeviceKind DeviceKind { get; }
+        public int Index { get; } // 1-4 for gamepads, 0 otherwise
+		public int Code { get; }
+
+        public ButtonIdentifier(Gamepad gamepad, ButtonCode buttonCode)
+        {
+			DeviceKind = DeviceKind.Gamepad;
+			Index = gamepad.Index;
+			Code = (int) buttonCode;
+		}
+
+        public ButtonIdentifier(KeyCode keyCode)
+        {
+			DeviceKind = DeviceKind.Keyboard;
+			Index = 0;
+			Code = (int) keyCode;
+		}
+
+        public ButtonIdentifier(MouseButtonCode mouseCode)
+        {
+			DeviceKind = DeviceKind.Mouse;
+			Index = 0;
+			Code = (int) mouseCode;
+		}
+	}
+}

src/Input/DeviceKind.cs

@@ -0,0 +1,9 @@
+namespace MoonWorks.Input
+{
+    public enum DeviceKind
+    {
+        Keyboard,
+        Mouse,
+        Gamepad
+    }
+}

src/Input/Gamepad.cs

@@ -8,6 +8,7 @@ namespace MoonWorks.Input
 	public class Gamepad
 	{
 		internal IntPtr Handle;
+		internal int Index;
 
 		public Button A { get; } = new Button();
 		public Button B { get; } = new Button();
@@ -39,9 +40,10 @@ namespace MoonWorks.Input
 		private Dictionary<SDL.SDL_GameControllerAxis, Axis> EnumToAxis;
 		private Dictionary<SDL.SDL_GameControllerAxis, Trigger> EnumToTrigger;
 
-		internal Gamepad(IntPtr handle)
+		internal Gamepad(IntPtr handle, int index)
 		{
 			Handle = handle;
+			Index = index;
 
 			EnumToButton = new Dictionary<SDL.SDL_GameControllerButton, Button>
 			{

src/Input/Input.cs

@@ -25,11 +25,11 @@ namespace MoonWorks.Input
 			{
 				if (SDL.SDL_IsGameController(i) == SDL.SDL_bool.SDL_TRUE)
 				{
-					gamepads[i] = new Gamepad(SDL.SDL_GameControllerOpen(i));
+					gamepads[i] = new Gamepad(SDL.SDL_GameControllerOpen(i), i);
 				}
 				else
 				{
-					gamepads[i] = new Gamepad(IntPtr.Zero);
+					gamepads[i] = new Gamepad(IntPtr.Zero, -1);
 				}
 			}
 		}
@@ -56,6 +56,27 @@ namespace MoonWorks.Input
 			return gamepads[slot];
 		}
 
+		public ButtonState ButtonState(ButtonIdentifier identifier)
+		{
+			if (identifier.DeviceKind == DeviceKind.Gamepad)
+			{
+				var gamepad = GetGamepad(identifier.Index);
+				return gamepad.ButtonState((ButtonCode) identifier.Code);
+			}
+			else if (identifier.DeviceKind == DeviceKind.Keyboard)
+			{
+				return Keyboard.ButtonState((KeyCode) identifier.Code);
+			}
+			else if (identifier.DeviceKind == DeviceKind.Mouse)
+			{
+				return Mouse.ButtonState((MouseButtonCode) identifier.Code);
+			}
+			else
+			{
+				throw new System.ArgumentException("Invalid button identifier!");
+			}
+		}
+
 		internal static void OnTextInput(char c)
 		{
 			if (TextInput != null)

src/Input/Mouse.cs

@@ -1,12 +1,13 @@
-using SDL2;
+using System.Collections.Generic;
+using SDL2;
 
 namespace MoonWorks.Input
 {
 	public class Mouse
 	{
-		public ButtonState LeftButton { get; private set; } = new ButtonState();
-		public ButtonState MiddleButton { get; private set; } = new ButtonState();
-		public ButtonState RightButton { get; private set; } = new ButtonState();
+		public Button LeftButton { get; } = new Button();
+		public Button MiddleButton { get; } = new Button();
+		public Button RightButton { get; } = new Button();
 
 		public int X { get; private set; }
 		public int Y { get; private set; }
@@ -30,6 +31,18 @@ namespace MoonWorks.Input
 			}
 		}
 
+		private readonly Dictionary<MouseButtonCode, Button> CodeToButton;
+
+		public Mouse()
+		{
+			CodeToButton = new Dictionary<MouseButtonCode, Button>
+			{
+				{ MouseButtonCode.Left, LeftButton },
+				{ MouseButtonCode.Right, RightButton },
+				{ MouseButtonCode.Middle, MiddleButton }
+			};
+		}
+
 		internal void Update()
 		{
 			var buttonMask = SDL.SDL_GetMouseState(out var x, out var y);
@@ -40,9 +53,14 @@ namespace MoonWorks.Input
 			DeltaX = deltaX;
 			DeltaY = deltaY;
 
-			LeftButton = LeftButton.Update(IsPressed(buttonMask, SDL.SDL_BUTTON_LMASK));
-			MiddleButton = MiddleButton.Update(IsPressed(buttonMask, SDL.SDL_BUTTON_MMASK));
-			RightButton = RightButton.Update(IsPressed(buttonMask, SDL.SDL_BUTTON_RMASK));
+			LeftButton.Update(IsPressed(buttonMask, SDL.SDL_BUTTON_LMASK));
+			MiddleButton.Update(IsPressed(buttonMask, SDL.SDL_BUTTON_MMASK));
+			RightButton.Update(IsPressed(buttonMask, SDL.SDL_BUTTON_RMASK));
+		}
+
+		public ButtonState ButtonState(MouseButtonCode buttonCode)
+		{
+			return CodeToButton[buttonCode].State;
 		}
 
 		private bool IsPressed(uint buttonMask, uint buttonFlag)

src/Input/MouseButtonCode.cs

@@ -0,0 +1,9 @@
+namespace MoonWorks.Input
+{
+    public enum MouseButtonCode
+    {
+        Left,
+        Right,
+        Middle
+    }
+}