阴影程序。画出四个物体，球体，正方体，圆环，圆柱体。然后画出两个发光体，查看这四个物体在两个光源下的阴影。其中的物体正方体在不断的旋转！-Shadow program. Draw four objects, sphere, cube, ring, cylinder. Then draw two light, see the four objects in the shadow of the two light sources. Objects which is constantly rotati