线索化包围盒层次结构的并行创建算法

Parallel construction algorithm for threaded-BVH

针对光线跟踪的场景加速结构创建问题,提出一种线索化包围盒层次结构(BVH)的图形处理器并行创建算法。算法完全以宽度优先搜索顺序创建包围盒结点,包括大结点和小结点两个创建过程,其分别并行化面片运算和结点运算,解决了创建上层结点时缺乏数据并行度的问题。算法通过3个独立步骤实现BVH的宽度优先到深度优先存储结构变换以及包围盒结点的线索化操作。实验结果表明,本文算法的创建速度高于已有的非线索化BVH创建算法。

Focusing on the issues of creating acceleration-structures of 3D scenes for ray tracing,a GPU-based parallel construction algorithm for threaded-Biovision Hierarchy（BVH） was proposed.The algorithm builds the Bounding-Volume Nodes（BVNs） completely in a breadth-first search order and includes two BVN construction processes.The first process is for upper large nodes,which parallelizes the computation over geometric primitives in each node,and the second is for lower small nodes,which parallelizes the computation over nodes at each level.These parallelization strategies can solve the problem of lacking parallelism in the construction process of upper large nodes.The algorithm performs operations of the BVH storage-structure transformation from the breadth-first to the depth-first order and threading computation of BVNs in three individual steps.Experiment results show that the construction speed of the proposed algorithm is faster than the existing unthreaded-BVH construction algorithm.