图的可视化输出，将无向图输出为图片形式，使用 Yapgvb 库-Graph visualization, outputing undirectional graph in image format, using Yapgvb

The Roamsteps code base offers an introduction to implementing the ROAM algorithm for accurate, high-performance display of large terrain datasets. The ideas the original 1997 ROAM paper have been updated significantly in many respects: the basic dat