KeyboardState.cs :  » Game » SDL » SdlDotNet » Input » C# / CSharp Open Source

#region LICENSE
/* 
 * $RCSfile$ 
 * Copyright (C) 2005 Rob Loach (http://www.robloach.net) 
 * 
 * This library is free software; you can redistribute it and/or 
 * modify it under the terms of the GNU Lesser General Public 
 * License as published by the Free Software Foundation; either 
 * version 2.1 of the License, or (at your option) any later version. 
 * 
 * This library is distributed in the hope that it will be useful, 
 * but WITHOUT ANY WARRANTY; without even the implied warranty of 
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
 * Lesser General Public License for more details. 
 * 
 * You should have received a copy of the GNU Lesser General Public 
 * License along with this library; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
#endregion LICENSE

using System;

using Tao.Sdl;

namespace SdlDotNet.Input{
    /// <summary> 
    /// The KeyboardState class interface describes the key state of every button on the keyboard. 
    /// </summary> 
    /// <example> 
    /// <code> 
    /// KeyboardState keys = new KeyboardState(); 
    /// 
    /// if( keys.IsKeyPressed(Key.A) ) 
    /// { 
    ///     // The A key is pressed. 
    /// } 
    ///      
    /// if( keys[Key.F] )   // Another way to check 
    /// { 
    ///     // The F key is currently down. 
    /// } 
    /// else 
    /// { 
    ///     // The F key is not down. 
    /// } 
    /// </code> 
    /// </example> 
    public class KeyboardState
    {
        #region Private fields

        /// <summary> 
        /// The state information of all the keys in the current state. 
        /// </summary> 
        private byte[] m_Keys;

        #endregion

        #region Constructors

        /// <summary> 
        /// Creates a new KeyboardState object with the current state of the keyboard. 
        /// </summary> 
        /// <remarks>This calls update on creation.</remarks>
        public KeyboardState()
            : this(true)
        {
        }

        /// <summary>
        /// Creates a new KeyboardState with an option to update on creation.
        /// </summary>
        /// <param name="updateNow">Update the key array on object creation.  Defaults to true.</param>
        public KeyboardState(bool updateNow)
        {
            if (updateNow)
            {
                Update();
            }
        }

        #endregion

        #region Public Methods

        /// <summary> 
        /// Gets the current state of the given key (true means the key is pushed, false if not). 
        /// </summary> 
        public bool this[Key key]
        {
            get
            {
                return m_Keys[(int)key] == 1;
            }
            set
            {
                m_Keys[(int)key] = value ? (byte)1 : (byte)0;
            }
        }

        /// <summary>
        /// Updates the keyboard state within this object.
        /// </summary>
        public void Update()
        {
            int numberOfKeys;
            m_Keys = Sdl.SDL_GetKeyState(out numberOfKeys);
        }

        /// <summary> 
        /// Checks a key state in the KeyboardState. 
        /// </summary> 
        /// <param name="key">The key to be checked.</param> 
        /// <returns>True if the key is pressed, false if it isn't.</returns> 
        public bool IsKeyPressed(Key key)
        {
            return m_Keys[(int)key] == 1;
        }

        #endregion
    }
}