Ray Traversal Temporal Coherence Optimization
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Solution Overview
Problem
Current node storage techniques in graphics processing are inefficient for storing acceleration structures, leading to increased computational intensity in ray traversal processes.
Innovation Solution
The proposed solution involves configuring a bounding volume hierarchy (BVH) for ray traversal and utilizing temporal coherence across frames to reduce the number of BVH tree hops, thereby optimizing the storage and access of acceleration structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If current node storage techniques are used to store acceleration structures, then the storage structure is simple, but the computational intensity in ray traversal processes increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing temporal coherence information (such as hit node IDs and tHit values) from previous frames before the current ray traversal begins. This allows the system to skip unnecessary BVH tree hops in the current frame by utilizing previously computed intersection data, thereby reducing computational intensity while maintaining storage simplicity
Solution Approach 2:
The patent uses copying by replicating relevant node identification data and temporal coherence information from previous frame computations into a cached structure. Instead of re-traversing the entire BVH tree, the system copies and reuses hit node IDs and associated metadata from prior frames, significantly improving ray traversal efficiency without complicating the storage architecture
2Productivity
If temporal coherence is utilized to reduce BVH tree hops, then the computational load decreases, but the memory access operations increase
Solution Approach 1:
The patent merges the storage of node identification data with temporal coherence information into a unified cached structure. By combining hit node IDs, tHit values, and other metadata into a single integrated cache, the system reduces the number of separate memory access operations while still providing all necessary information for temporal coherence-based ray traversal optimization
Data Source
AI summary
Aspects presented herein relate to methods and devices for graphics processing including an apparatus, e.g., a GPU. The apparatus may perform a ray traversal process for a second frame in a set of frames starting at a first node in a plurality of nodes, where a ray in the ray traversal process previously intersected a first primitive in a first frame, where the first primitive corresponds to a first node ID. The apparatus may also detect whether the ray intersects the first primitive in the second frame. Further, the apparatus may store the first node ID for the first node based on the ray intersecting the first primitive in the second frame, or re-perform the ray traversal process for the second frame starting at a root node in the plurality of nodes based on the ray not intersecting the first primitive in the second frame.