SAH-KD-tree design method used for light ray tracking

Abstract

The invention provides an SAH-KD-tree design method used for light ray tracking. The method includes: step S1, preprocessing all triangular surface slices of a current root node in nodes before construction of a SAH-KD tree is carried out; step S2, recursively constructing the SAH-KD tree according to layers, generating an ordered bounding box sequence of left and right child nodes of the currentnode, and calculating surface areas of three dimensions of a bounding box of each node of a current layer; step S3, obtaining, by solving, dimensions which are of the current nodes and need to be divided, generating a space tree and candidate division points of all the nodes of each layer, and calculating an SAH value corresponding to each candidate division point; and step S4, selecting a candidate division point, which corresponds to a smallest SAH value, to use the same as an optimal division point of the current nodes, and dividing the current node into two child nodes of a left and a right. Compared with the related art, the SAH-KD tree design method used for light ray tracking provided by the invention constructs the SAH-KD tree with good performance and high efficiency.

Description

technical field [0001] The invention relates to the technical field of data processing, in particular to a SAH-KD tree design method for ray tracing. Background technique [0002] K-dimensional tree (KD tree) is a kind of balanced binary tree aligned with coordinate axes. It is a data structure commonly used for space division in K-dimensional space. It is widely used as an acceleration structure in graphics applications and query fields, such as ray tracing. Intersection detection between triangular faces and rays, nearest neighbor query, etc. The traversal cost of the KD tree has different calculation methods in different application fields. In ray tracing, it is necessary to calculate all the leaf nodes of the KD tree that each ray passes through. In order to achieve efficient traversal, the surface area heuristic partition method (SAH) is usually used during construction, and the partition point is selected by minimizing the intersection test complexity between the tria...

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Problems solved by technology

[0003] In related technologies, in order to quickly and efficiently construct the SAH-KD tree used for ray tracing, one method is a serial construction method, and the simplest idea is to fully perform all division points on each node of the constructed SAH-KD tree Traversing to calculate the SAH value, its computational complexity is O(N 2 ), due to the high computational complexity, this method cannot be applied to large scenes; the other is the parallel construction method, which uses a high-performance thread to perform calculations on the upper-level large nodes until the calculation amount of each node is small enough, then the They are assigned to the construction idea of ​​the multi-core system. Although this method improves the construction efficiency of the SAH-KD tree, the efficiency of the median selection at the top layer is somewhat degraded when the algorithm is traversed, and there are different degrees of performance loss in super-large scenarios.

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