半透明物体的PRT绘制算法

The PRT Rendering Algorithm of Translucent Object

将传统的PRT(Pre-com puted Radiance Transfer)算法应用到半透明的物体上,提出了一种在任意复杂的环境光条件下使用非线性小波绘制半透明物体的快速算法。算法首先对场景中的每一个顶点计算一个转换向量,并且对每一个向量进行小波变换,保存量化后的小波系数;然后用相同的小波基对给定的环境光做小波变换,只保留其中绝对值较大的系数,从而得到环境光的非线性逼近。文章的算法可以将绘制物体的复杂的积分运算简化为N个稀疏向量间的乘积(N是场景中顶点的数目),从而达到实时的绘制速度。论文通过实验验证了算法的有效性。

This paper presents a new fast algorithm,based on pre-computed light transport,for rendering translucent objects under all-frequency and complex illumination represented as a high-resolution environment map.The method firstly computes a vector on each vertex of the scene,and approximate these vectors using wavelet transform.Then,it approximates the environment map in the same wavelet basis by keeping only the largest terms to get a non-linear approximation of the environment-map.The algorithm is performed by multiplying a sparse light vector by N sparse tra nsport vectors,which can achieve real-time rendering speed.Experiments show that the algorithm presented is effective.