绘制若干个透明和非透明茶壶，并体现出它们之间正确的混合效果；实现放大镜功能，放大场景中的任意部分； 放大镜可以通过鼠标键盘进行控制；-Draw a number of transparent and non-transparent teapot, and they reflect mixed results magnifying glass feature to enlarge any part of the scene magnifying glass can be controlle