The algorithm acquired constant frame rates by searching the hierachical quadtree in a topdown manner.The rendering speed was also benefited from the coherence of frames and triangle fans.

• 采用自顶向下搜索层次四叉树的方法以获得恒定的帧频，并利用相邻帧之间的连续性和三角形扇形结构提高地形的实时绘制速度。