基于光子分布概率调整的高效的非匀质半透明材质绘制

Efficient Inhomogeneous Translucent Material Rendering Based on Probability Adjustment of Photon Distribution

针对非匀质半透明材质绘制代价高昂的问题,提出一种基于光子分布概率调整的高效非匀质半透明物体绘制算法.首先利用绘制图像所显现的区域生成场景中的关注区域;然后依据体积光子映射算法从光源处随机生成光子并进行跟踪;若光子与关注区域相交,则对该光子的分布概率进行调整,通过降低其能量来增加其落在关注区域内的概率;最后在概率调整时对高能量光子在方向上和在距离上进行切分,以保证关注区域内光子能量一致.实验结果表明,该算法能显著增加关注区域内的光子密度,并有效地减少非匀质半透明材质绘制的时间.

To address the high cost of inhomogeneous translucent material rendering, this paper presents an efficient rendering algorithm for inhomogeneous translucent objects based on probability adjustment of photon distribution. Firstly, the focusing area is computed by the frustum of rendering image. Then photons are randomly generated from light sources and traced according to volumetric photon mapping algorithm. If a photon intersects with the focusing area, its distribution probability is adjusted by decreasing its power and increasing its distribution probability in the focusing area. Finally, high power photons are split in the dimensions of angle and distance respectively during probability adjustment to satisfy the uniform photon power constraint inside the focusing area. Experimental results show that this algorithm can significantly increase photon density inside the focusing area and effectively reduce the computation cost of inhomogeneous translucent material rendering.