Introduction - If you have any usage issues, please Google them yourself
1. Draw a three-dimensional object by using the OpenGL function;
2. Use the mouse or keyboard to control the movement, rotation and contraction of 3D objects on the screen
(1) mobile: can not directly call the OpenGL geometric transformation function, use the homogeneous coordinate, and use the way of matrix multiplication to achieve their own programming.
(2) the OpenGL function can be invoked for rotation and contraction