opengl的一个鼠标跟随特效。随着鼠标的移动，会有出现各种效果，相当绚丽-opengl follow the effects of a mouse. As the mouse moves, there will be a variety of effects, very beautiful

1、用鼠标拖动画直线，线段终点始终跟随鼠标移动； 2、使用菜单界面修改直线的颜色； 3、利用键盘控制直线在屏幕上移动；(1, using the mouse to drag the straight line, the end of the line is always followed by the mouse movement; 2, use the menu interface to modify the color of the straight line. 3, use th