基于分类及环境特征的树木真实感绘制

生成高度真实感的虚拟自然场景一直是图形学研究领域中的一个富有挑战性的难题.作为自然场景的重要组成部分,树木的真实感模拟也得到人们的广泛重视.树木种类繁多,形态各异,复杂的结构使其无论在造形、存储还是在绘制上都存在着相当的困难.针对不同的环境特征和不同类型的树木,根据它们的具体特点需采用不同的绘制手段.对于阔叶树,采用基于OpenGL的深度缓存阴影生成算法;对于针叶树,则采用结合光线跟踪和纹元(texel)绘制的技术;而对于距离视点比较远的树,采用的是体纹理映射(volumetrictexturemapping)的方法.实践证明,这几种绘制技术基本上可以满足各种不同类型场景的树木的绘制要求.

Realistic Rendering of Trees Based on Environmental Features and Spec ies

Generation of photo-realistic images of virtual nature scenes is a challenging topic in computer graphics. As a very important part of natural scenery, realist ic rendering of trees has attracted much attention. Trees have various types wit h different shapes and due to their complex structures, realistic modelings, ren dering and storage of trees are always a tedious task. To tackle the problem, di fferent rendering strategies ae employed according to different types of trees a nd different scenes. For broadleaf, the z-buffer shadow generation method is us ed based on primary functions of OpenGL, for conifer, a ray tracing algorithm in cluding texel-rendering technique is used, and for trees in the far distance, v olumetric texture mapping is employed in terms of ray tracing and volume renderi ng technique. The images produced show that the feasibility and validity of the proposed rendering techniques.