/Samples/Breakout/Paddle.cs

using System.Collections.Generic;

using DeltaEngine.Commands;

using DeltaEngine.Content;

using DeltaEngine.Datatypes;

using DeltaEngine.Entities;

using DeltaEngine.Extensions;

using DeltaEngine.Input;

using DeltaEngine.Rendering2D;



namespace Breakout

{

	/// <summary>

	/// Holds the paddle position

	/// </summary>

	public class Paddle : Sprite

	{

		public Paddle()

			: base(new Material(ShaderFlags.Position2DColoredTextured, "Paddle"), Rectangle.One)

		{

			RegisterInputCommands();

			Start<RunPaddle>();

			RenderLayer = 5;

		}



		private void RegisterInputCommands()

		{

			RegisterButtonCommands();

			new Command(DoMovementByMouseClick).Add(

				new MouseButtonTrigger(MouseButton.Left, State.Pressed));

		}



		private void DoMovementByMouseClick(Vector2D clickPosition)

		{

			var moveDistAbsolute = PaddleMovementSpeed * Time.Delta;

			var distance = clickPosition.X - xPosition;

			if (distance.Abs() < moveDistAbsolute)

			{

				xPosition = clickPosition.X;

				return;

			}

			xPosition += distance > 0 ? moveDistAbsolute : -moveDistAbsolute;

		}



		private void RegisterButtonCommands()

		{

			var left = new Command(() => xPosition -= PaddleMovementSpeed * Time.Delta);

			left.Add(new KeyTrigger(Key.CursorLeft, State.Pressed));

			left.Add(new GamePadButtonTrigger(GamePadButton.Left, State.Pressed));

			var right = new Command(() => xPosition += PaddleMovementSpeed * Time.Delta);

			right.Add(new KeyTrigger(Key.CursorRight, State.Pressed));

			right.Add(new GamePadButtonTrigger(GamePadButton.Right, State.Pressed));

		}



		private float xPosition = 0.5f;

		private const float PaddleMovementSpeed = 1.5f;



		public class RunPaddle : UpdateBehavior

		{

			public override void Update(IEnumerable<Entity> entities)

			{

				foreach (var entity in entities)

				{

					var paddle = (Paddle)entity;

					var xPosition = paddle.xPosition.Clamp(HalfWidth, 1.0f - HalfWidth);

					paddle.xPosition = xPosition;

					paddle.DrawArea = Rectangle.FromCenter(xPosition, YPosition, Width, Height);

				}

			}

		}



		private const float YPosition = 0.9f;

		internal const float HalfWidth = Width / 2.0f;

		private const float Width = 0.2f;

		private const float Height = 0.04f;



		public Vector2D Position

		{

			get { return new Vector2D(DrawArea.Center.X, DrawArea.Top); }

		}

	}

}