本例的功能是显示茶壶图像的景深效果。再连续5个茶壶的图像中，其中一个处于焦点处，其他的茶壶随着其焦点处的距离而逐渐变得模糊。-cases of this function is to show the depth of field teapot image effects. Another five consecutive images of teapots, which is a focus, other teapot with its focus away from the graduall