On the one hand . creating virtual scene of complicated traffic facility ( for example crossroads ) by using opengl has become very difficult . the research and application of driving simulator has been furthered and extended and the virtual scene models come to more complex 但是,一方面,由于驾驶模拟器的研究领域和应用范围的扩展,构造的虚拟场景的复杂度加大,使用opengl从底层构造像立交桥这样复杂的交通设施的虚拟场景,已经显得力不从心了。