用xaml画的带阴影3D感的圆球

<StackPanel VerticalAlignment="Center" HorizontalAlignment="Center">
        <Ellipse Width="120" Height="120">
            <Ellipse.Fill>
                <RadialGradientBrush GradientOrigin="0.25,0.25" RadiusX="0.75" RadiusY="0.75">
                    <RadialGradientBrush.GradientStops>
                        <GradientStop Color="Red" Offset="0" />
                        <GradientStop Color="Orange" Offset="0.65" />
                        <GradientStop Color="Yellow" Offset="0.8" />
                    </RadialGradientBrush.GradientStops>
                </RadialGradientBrush>
            </Ellipse.Fill>
        </Ellipse>
</StackPanel>