WPF使用HLSL实现百叶窗动画效果

public class BlindsShader : ShaderEffect
{
    public static readonly DependencyProperty InputProperty = ShaderEffect.RegisterPixelShaderSamplerProperty("Input", typeof(BlindsShader), 0);
    public static readonly DependencyProperty ProgressProperty = DependencyProperty.Register("Progress", typeof(double), typeof(BlindsShader), new UIPropertyMetadata(((double)(30D)), PixelShaderConstantCallback(0)));
    public static readonly DependencyProperty NumberOfBlindsProperty = DependencyProperty.Register("NumberOfBlinds", typeof(double), typeof(BlindsShader), new UIPropertyMetadata(((double)(5D)), PixelShaderConstantCallback(1)));
    public static readonly DependencyProperty Texture2Property = ShaderEffect.RegisterPixelShaderSamplerProperty("Texture2", typeof(BlindsShader), 1);
    public BlindsShader()
    {
        PixelShader pixelShader = new PixelShader();
        pixelShader.UriSource = new Uri("/WPFTest;component/Shader/ShaderSource/BlindsShader.ps", UriKind.Relative);
        this.PixelShader = pixelShader;
        this.UpdateShaderValue(InputProperty);
        this.UpdateShaderValue(ProgressProperty);
        this.UpdateShaderValue(NumberOfBlindsProperty);
        this.UpdateShaderValue(Texture2Property);
    }
    public Brush Input
    {
        get
        {
            return ((Brush)(this.GetValue(InputProperty)));
        }
        set
        {
            this.SetValue(InputProperty, value);
        }
    }
    /// <summary>The amount(%) of the transition from first texture to the second texture. </summary>
    public double Progress
    {
        get
        {
            return ((double)(this.GetValue(ProgressProperty)));
        }
        set
        {
            this.SetValue(ProgressProperty, value);
        }
    }
    /// <summary>The number of Blinds strips </summary>
    public double NumberOfBlinds
    {
        get
        {
            return ((double)(this.GetValue(NumberOfBlindsProperty)));
        }
        set
        {
            this.SetValue(NumberOfBlindsProperty, value);
        }
    }
    public Brush Texture2
    {
        get
        {
            return ((Brush)(this.GetValue(Texture2Property)));
        }
        set
        {
            this.SetValue(Texture2Property, value);
        }
    }
}

<Window.Resources>
    <ImageBrush x:Key="imageBrush" ImageSource="111.jpg" />
    <ImageBrush x:Key="blindsBrush" ImageSource="blinds.jpg" />
    <local:BlindsShader x:Key="BlindsShader"
                        NumberOfBlinds="4"
                        Progress="0"
                        Texture2="{StaticResource blindsBrush}" />
    <Storyboard x:Key="DefaultBlindsShaderStoryboard" FillBehavior="HoldEnd">
        <DoubleAnimation Storyboard.TargetProperty="(UIElement.Effect).(local:BlindsShader.Progress)"
                            From="0"
                            To="100"
                            Duration="00:00:1.5" />
        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Effect)">
            <DiscreteObjectKeyFrame KeyTime="00:00:1.5" Value="{x:Null}" />
        </ObjectAnimationUsingKeyFrames>
    </Storyboard>
</Window.Resources>
<Grid Background="{StaticResource imageBrush}" Effect="{StaticResource BlindsShader}">
    <Grid.Triggers>
        <EventTrigger RoutedEvent="FrameworkElement.Loaded">
            <BeginStoryboard x:Name="sbLoaded" Storyboard="{DynamicResource DefaultBlindsShaderStoryboard}" />
        </EventTrigger>
    </Grid.Triggers>
</Grid>