基于级联体素纹理的VCT全局光照算法

针对大规模场景的全局光照渲染往往因为计算量过大而无法满足实时性要求的问题进行了研究，提出一种高性能的体素圆锥追踪（VCT）全局光照算法。算法包括：a）在体素化阶段，提出一种新型的场景光照信息表示级联体素纹理结构，该结构极大地减少了存储场景的内存消耗而且具有各向异性，在处理大规模场景时具有速度快、质量高的优势；b）在光照计算阶段，基于级联体素纹理结构提出一种改进的圆锥追踪滤波器，能够提高光照注入和反射光计算的效率；c）改进场景的体素化更新策略进一步提高了算法的运行时帧率。实验证明，本算法在降低内存占用空间和提高速度方面均远优于原VCT算法，满足了大规模场景中全局光照计算的实时性要求。

VCT global illumination algorithm based on cascade voxel texture

To solve the problem that the global illumination rendering of large scale scene can''t meet the real-time requirement, this paper proposed a voxel cone tracking(VCT) global illumination algorithm. The algorithm included: a) In the phase of voxelization, this paper proposed a novel scene illumination information representation structure called cascade voxel textures, this structure could not only greatly reduce the memory consumption of the storage scenes, but also had anisotropy; b) In the phase of illumination calculation, this paper proposed an improved cone tracing filter based on the cascade texture structure, this filter improved the efficiency of illumination injection and reflected light calculation; c) the voxel updating strategy of the scene improved the runtime frame rate of the algorithm. Experimental results show that the proposed algorithm is much better than the original VCT algorithm in reducing the memory and improving the speed. The algorithm meets the real-time requirement of global illumination calculation in large-scale scene.