在屏幕上画出立方体一点透视图，立方体的八个顶点坐标（0,0,0）（0,0,400），（0,400,0),(400,0,400),(400,400,400)(400,400,0)视点定于（800,0,0），视距为4-Point perspective for the cube on the screen to draw a map, cube eight vertex coordinates (0,0,0) (0,0,400), (0,400,0), (400,0,400) (400,400,400) (400,400,0) viewpoint scheduled for (800,0,0), line-of-sight 400