用于计算在三维点云处理过程中的局部点云面积估算，精度很高。-Used to calculate the three-dimensional point cloud processing local point cloud area estimation accuracy is very high.

unity中通过 opengl画出不规则的闭合图形，计算不规则图形的面积，并测试任意一点是否在图形内部。-unity through opengl to draw irregular closed figures, calculate the area of irregular shapes, and test whether any point in the graphics inside.