分析了双向反射分布函数、试验数据经验拟合公式、OpenGL中的Phong公式等几种目标表面材料面元的光学反射特征模型之间的差异.应用面元的双向反射分布函数推导出在阳光、天地背景光照下材料表面的反射光强分布函数的简化公式,讨论了OpenGL简化模型对光学特征仿真的影响.基于OpenGL系统,提出了3D模型建立途径和材料光学参数的选取方法,对复杂形体光学特征仿真中阴影和天地背景光目标照明的实现提出了相应的OpenGL算法,并给出仿真结果.

Expression of the reflex effect of natural lighting is a key problem of optic character simulation. The difference among the optic reflex character models of several target surface material facets, such as the facet's BRDF, experimental fit curve and expression of Phong in OpenGL, is analyzed. The material optic distribution in sun and sky (or earth) lighting is derived using the facet's BRDF. The effect of simplified OpenGL model on simulation of optic character is discussed. Based on OpenGL system, the methods of setting up 3D model and choosing material's optic parameter are given. The algorithm of complex target's optic character simulation in natural lighting is proposed and the result of the simulation is also presented.