MonoGame.Samples/StarterKits/iOS/Marblets/GamePadHelper.cs

#region File Description
//-----------------------------------------------------------------------------
// GamePadHelper.cs
//
// Microsoft XNA Community Game Platform
// Copyright (C) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------
#endregion

#region Using Statements
using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework;
#endregion

namespace Marblets
{
	/// <summary>
	/// Useful class that wraps some game pad stuff to give you indication of single 
	/// button presses by remembering previous state. Right now its one shot which means
	/// if you call a Pressed function that will 'remove' the press.
	/// 
	/// Keyboard support should be mapped in here based on PlayerIndex.
	/// PlayerIndex.One Key mapping is (Keys for player one to use)
	/// PlayerIndex.Two Key mapping is (Keys for Player two to use)
	/// Players Three => Infinity are not supported on a keyboard!
	/// </summary>
	public enum GamePadKey
	{
		/// <summary>
		/// Start button
		/// </summary>
		Start=0,
		/// <summary>
		/// Back buton
		/// </summary>
		Back,
		/// <summary>
		/// A button
		/// </summary>
		A,
		/// <summary>
		/// B button
		/// </summary>
		B,
		/// <summary>
		/// X button
		/// </summary>
		X,
		/// <summary>
		/// Y button
		/// </summary>
		Y,
		/// <summary>
		/// Up Dpad
		/// </summary>
		Up,
		/// <summary>
		/// Down Dpad
		/// </summary>
		Down,
		/// <summary>
		/// Left Dpad
		/// </summary>
		Left,
		/// <summary>
		/// Right Dpad
		/// </summary>
		Right,
	};

	/// <summary>
	/// XNA gamepads only give you 'isUp/Down' options for buttons and key presses. 
	/// This class allows you to detect an up/down press combination
	/// </summary>
	public class GamePadHelper
	{
		private PlayerIndex player;
		private Dictionary<GamePadKey, Keys> keyMapping = 
                                             new Dictionary<GamePadKey, Keys>();

		private Game game;

		/// <summary>
		/// Default constructor
		/// </summary>
		/// <param name="player">Which player.</param>
		public GamePadHelper(PlayerIndex player)
		{
			//Need to store the player. If you try to store a reference to the GamePad
			//here it seems to 'forget'
			this.player = player;

			// Setup Dictionary with defaults
			keyMapping.Add(GamePadKey.Start, Keys.Home);
			keyMapping.Add(GamePadKey.Back, Keys.End);
			keyMapping.Add(GamePadKey.A, Keys.A);
			keyMapping.Add(GamePadKey.B, Keys.B);
			keyMapping.Add(GamePadKey.X, Keys.X);
			keyMapping.Add(GamePadKey.Y, Keys.Y);
			keyMapping.Add(GamePadKey.Up, Keys.Up);
			keyMapping.Add(GamePadKey.Down, Keys.Down);
			keyMapping.Add(GamePadKey.Left, Keys.Left);
			keyMapping.Add(GamePadKey.Right, Keys.Right);
		}


		private bool AWasReleased;
		private bool BWasReleased;
		private bool YWasReleased;
		private bool XWasReleased;
		private bool StartWasReleased;
		private bool BackWasReleased;
		private bool UpWasReleased;
		private bool DownWasReleased;
		private bool LeftWasReleased;
		private bool RightWasReleased;

		private bool AKeyWasReleased;
		private bool BKeyWasReleased;
		private bool YKeyWasReleased;
		private bool XKeyWasReleased;
		private bool StartKeyWasReleased;
		private bool BackKeyWasReleased;
		private bool UpKeyWasReleased;
		private bool DownKeyWasReleased;
		private bool LeftKeyWasReleased;
		private bool RightKeyWasReleased;

		private GamePadState state;
		private KeyboardState keyState;


		/// <summary>
		/// Has the A button been pressed
		/// </summary>
		public bool APressed
		{
			get
			{
				return (
					   (checkPressed(state.Buttons.A, ref AWasReleased)) ||
                       (checkPressed(keyState.IsKeyDown(keyMapping[GamePadKey.A]),
						ref AKeyWasReleased))
						);
			}
		}

		/// <summary>
		/// Has the B button been pressed
		/// </summary>
		public bool BPressed
		{
			get
			{
				return (
					   (checkPressed(state.Buttons.B, ref BWasReleased)) ||
                       (checkPressed(keyState.IsKeyDown(keyMapping[GamePadKey.B]),
						ref BKeyWasReleased))
						);
			}
		}

		/// <summary>
		/// Has the Y button been pressed
		/// </summary>
		public bool YPressed
		{
			get
			{
				return (
					   (checkPressed(state.Buttons.Y, ref YWasReleased)) ||
                       (checkPressed(keyState.IsKeyDown(keyMapping[GamePadKey.Y]),
						ref YKeyWasReleased))
						);
			}
		}

		/// <summary>
		/// Has the X button been pressed
		/// </summary>
		public bool XPressed
		{
			get
			{
				return (
					   (checkPressed(state.Buttons.X, ref XWasReleased)) ||
                       (checkPressed(keyState.IsKeyDown(keyMapping[GamePadKey.X]),
						ref XKeyWasReleased))
						);
			}
		}

		/// <summary>
		/// Has the start button been pressed
		/// </summary>
		public bool StartPressed
		{
			get
			{
				return (
					   (checkPressed(state.Buttons.Start, ref StartWasReleased)) ||
                       (checkPressed(keyState.IsKeyDown(keyMapping[GamePadKey.Start]),
						ref StartKeyWasReleased))
						);
			}
		}

		/// <summary>
		/// Has the back button been pressed
		/// </summary>
		public bool BackPressed
		{
			get
			{
				return (
					   (checkPressed(state.Buttons.Back, ref BackWasReleased)) ||
                       (checkPressed(keyState.IsKeyDown(keyMapping[GamePadKey.Back]),
						ref BackKeyWasReleased))
						);
			}
		}

		/// <summary>
		/// Has the up dpad been pressed
		/// </summary>
		public bool UpPressed
		{
			get
			{
				return (
					   (checkPressed(state.DPad.Up, ref UpWasReleased)) ||
                       (checkPressed(keyState.IsKeyDown(keyMapping[GamePadKey.Up]),
						ref UpKeyWasReleased))
						);
			}
		}

		/// <summary>
		/// Has the down dpad been pressed
		/// </summary>
		public bool DownPressed
		{
			get
			{
				return (
					   (checkPressed(state.DPad.Down, ref DownWasReleased)) ||
                       (checkPressed(keyState.IsKeyDown(keyMapping[GamePadKey.Down]),
						ref DownKeyWasReleased))
						);
			}
		}

		/// <summary>
		/// Has the left dpad been pressed
		/// </summary>
		public bool LeftPressed
		{
			get
			{
				return (
					   (checkPressed(state.DPad.Left, ref LeftWasReleased)) ||
                       (checkPressed(keyState.IsKeyDown(keyMapping[GamePadKey.Left]),
						ref LeftKeyWasReleased))
						);
			}
		}

		/// <summary>
		/// Has the right dpad been pressed
		/// </summary>
		public bool RightPressed
		{
			get
			{
				return (
					   (checkPressed(state.DPad.Right, ref RightWasReleased)) ||
                       (checkPressed(keyState.IsKeyDown(keyMapping[GamePadKey.Right]),
						ref RightKeyWasReleased))
						);
			}
		}

		private bool checkPressed(ButtonState buttonState, ref bool controlWasReleased)
		{
			//Buttons are considered pressed when their state = Pressed or their key 
			//equivalent is down
			return checkPressed(buttonState == ButtonState.Pressed,
								ref controlWasReleased);
		}

		private bool checkPressed(bool pressed, ref bool controlWasReleased)
		{
			bool returnValue = controlWasReleased && pressed;
			if(game != null && game.IsActive)
			{
				//If the item is currently pressed then reset the 'released' indicators
				if(returnValue)
				{
					controlWasReleased = false;
				}
			}
			else
			{
				return false;  // Control can never be pressed, game is not the active 
				// application!
			}

			return returnValue;
		}


		/// <summary>
		/// Updates the states. Should be called once per frame in the game loop 
		/// otherwise the IsPressed functions won't work
		/// </summary>
		public void Update(Game game)
		{
			state = GamePad.GetState(player);

			keyState = Keyboard.GetState();

			this.game = game;

			if(state.IsConnected)
			{
				//Check which buttons have been released so we can detect presses
				if((state.Buttons.A == ButtonState.Released))
					AWasReleased = true;
				if((state.Buttons.B == ButtonState.Released))
					BWasReleased = true;
				if((state.Buttons.Y == ButtonState.Released))
					YWasReleased = true;
				if((state.Buttons.X == ButtonState.Released))
					XWasReleased = true;
				if((state.Buttons.Start == ButtonState.Released))
					StartWasReleased = true;
				if((state.Buttons.Back == ButtonState.Released))
					BackWasReleased = true;
				if((state.DPad.Up == ButtonState.Released))
					UpWasReleased = true;
				if((state.DPad.Down == ButtonState.Released))
					DownWasReleased = true;
				if((state.DPad.Left == ButtonState.Released))
					LeftWasReleased = true;
				if((state.DPad.Right == ButtonState.Released))
					RightWasReleased = true;
			}

			//Check which keys on the keyboard have been released so we can detect 
			//presses
			if(!keyState.IsKeyDown(keyMapping[GamePadKey.A]))
				AKeyWasReleased = true;
			if(!keyState.IsKeyDown(keyMapping[GamePadKey.B]))
				BKeyWasReleased = true;
			if(!keyState.IsKeyDown(keyMapping[GamePadKey.Y]))
				YKeyWasReleased = true;
			if(!keyState.IsKeyDown(keyMapping[GamePadKey.X]))
				XKeyWasReleased = true;
			if(!keyState.IsKeyDown(keyMapping[GamePadKey.Start]))
				StartKeyWasReleased = true;
			if(!keyState.IsKeyDown(keyMapping[GamePadKey.Back]))
				BackKeyWasReleased = true;
			if(!keyState.IsKeyDown(keyMapping[GamePadKey.Up]))
				UpKeyWasReleased = true;
			if(!keyState.IsKeyDown(keyMapping[GamePadKey.Down]))
				DownKeyWasReleased = true;
			if(!keyState.IsKeyDown(keyMapping[GamePadKey.Left]))
				LeftKeyWasReleased = true;
			if(!keyState.IsKeyDown(keyMapping[GamePadKey.Right]))
				RightKeyWasReleased = true;
		}
	}
}