[Silverlight动画]转向行为 - 寻找行为

        public void seek(Vector2D target)
        {
            Vector2D desiredVelocity = target.subtract(_postion);
            desiredVelocity.normalize();
            desiredVelocity = desiredVelocity.multiply(_maxSpeed);
            Vector2D force = desiredVelocity.subtract(_velocity);
            _steeringForce = _steeringForce.add(force);
        }

<UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:Steer" xmlns:ed="http://schemas.microsoft.com/expression/2010/drawing"
	x:Class="Steer.SeekTest"
	d:DesignWidth="640" d:DesignHeight="480" mc:Ignorable="d">

	<Grid x:Name="LayoutRoot" Background="White">
		<local:SteeredVehicle x:Name="myStar" HorizontalAlignment="Left" Height="40" VerticalAlignment="Top" Width="40">
			<ed:RegularPolygon Fill="Blue" Height="40" InnerRadius="1" PointCount="3" Stretch="Fill" Stroke="Black" UseLayoutRounding="False" Width="40" RenderTransformOrigin="0.5,0.5" StrokeThickness="0">
				<ed:RegularPolygon.RenderTransform>
					<CompositeTransform Rotation="90"/>
				</ed:RegularPolygon.RenderTransform>
			</ed:RegularPolygon>
		</local:SteeredVehicle>
	</Grid>
</UserControl>

	public partial class SeekTest : UserControl
	{
        double mouseX = 0;
        double mouseY = 0;
		public SeekTest()
		{
			// Required to initialize variables
			InitializeComponent();

            Loaded += new RoutedEventHandler(SeekTest_Loaded);
		}

        void SeekTest_Loaded(object sender, RoutedEventArgs e)
        {
            //myStar.position = new Vector2D(100, 100);
            //myStar.velocity.length = 5;
            //myStar.velocity.angle = Math.PI / 4;

            MouseMove += new MouseEventHandler(SeekTest_MouseMove);
            CompositionTarget.Rendering += new EventHandler(CompositionTarget_Rendering);
        }

        void CompositionTarget_Rendering(object sender, EventArgs e)
        {
            myStar.seek(new Vector2D(mouseX, mouseY));
            myStar.update();
        }

        void SeekTest_MouseMove(object sender, MouseEventArgs e)
        {
            mouseX = e.GetPosition(null).X;
            mouseY = e.GetPosition(null).Y;
        }
	}