OpenGL,地球模型，纹理加载，虚拟跟踪球的实现-OpenGL, the Earth model, texture loading, the realization of a virtual tracking ball

实现了MFC下OpenGL环境的设置，非模式对话框，DEM高程数据读取，鼠标滚轮控制放大缩小-MFC achieved under the OpenGL environment settings, non-modal dialog, DEM elevation data to read, the mouse wheel control the zoom

实现空间坐标轴的显示，并通过鼠标进行交互，能实现身拖拽旋转，滚轮放大缩小，Opengl学习必备入门程序，并已封装好了各种类，方便学习-Realization of display space axes and interact with the mouse, drag the body to achieve rotation, zoom, Opengl learning essential entry procedures, and have a good package of various

三维重构的思路很简单，用OpenGL中纹理贴图功能，将平面图像中的三角形逐个贴到计算出的三维坐标上去就可以了。为了便于观察3D效果，我还设计了交互功能：用方向键可以上下左右旋转重构的模型，用鼠标滚轮可以放大或缩小。用gluLookAt函数可以实现视点旋转的功能。三维重构的代码实现在glFuncs.cpp中。(Three-dimensional reconstruction of the idea is very simple, with OpenGL texture mapping functi