动态非均质半透明物体的实时绘制算法  

Real Time Rendering of Dynamic Heterogeneous Translucent Materials

作　　者：宋滢[1] 童欣[2] 石教英[1] 

机构地区：[1]浙江大学CAD&CG国家重点实验室,杭州310058 [2]微软亚洲研究院网络图形组,北京100190

出　　处：《计算机辅助设计与图形学学报》2009年第9期1212-1218,共7页Journal of Computer-Aided Design & Computer Graphics

摘　　要：现有的对半透明物体的绘制算法中大部分都是为均质材质设计的,虽然有少数算法可以绘制非均质材质,但效率不高,为此提出一种图形硬件加速的动态非均质半透明物体的实时绘制算法.首先将模型的采样点组织成八叉树的形式,将双向次表面散射反射函数(BSSRDF)表达绑定为顶点属性,同时充分利用图形硬件的并行性来实现八叉树的快速建立和遍历;然后以树的结点之间的空间距离和材质的相似度为准则提出一种新的采样方法来提高表面积分的效率.由于整个过程不需要任何预计算,因此该算法可以很容易地扩展到动画场景或者变化的材质,并且还可以灵活地选择BSSRDF的表达方式.实验结果表明,文中算法可以达到实时的绘制帧率和良好的视觉效果.Most of the existing rendering algorithms for translucent materials are designed only for homogeneous materials. Although some algorithms can be used to render heterogeneous materials, they are not efficient enough. This paper provides a real time GPU-accelerated rendering algorithm for heterogeneous translucent dynamic objects. By the method, the mesh vertices are organized first into an octree hierarchy to better explore the parallelism of hierarchy construction by traversing in the graphics hardware, with the bidirectional subsurface scattering reflectance distributed functions （BSSRDF） bound as a per-vertex property. Second, to evaluate the integration over the object surface efficiently, a novel sampling method is also proposed based on the distance between tree nodes and the material similarity. This algorithm can be easily extended to render animated scenes and dynamic materials because no precomputation is needed, and it is flexible for various BSSRDF representations. Experimental results demonstrated that the proposed algorithm achieves real time frame rates and good visual effects.

关 键 词：次表面散射 双向次表面散射反射分布函数 实时绘制 八叉树 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]