openGl写的，立方体和布置添加阴影，适合初学者看，大家一起交流哈~-openGl written and arranged to add the shadow of the cube, suitable for beginners to read, share with everyone ha ~

使用 OpenGL 进行三维地形的绘制的源代码，能够通过输入参数值确定地形的坡度-Using OpenGL for rendering of the source code for the three-dimensional terrain, through the input parameter values ​ ​ to determine the slope of the terrain