Multi-GPU room response simulation with hardware raytracing

Time-of-flight camera systems are an essential component in 3D scene analysis and reconstruction for many modern computer vision applications. The development and validation of such systems require testing in a large variety of scenes and situations. Accurate room impulse response simulation greatly speeds up development and validation, as well as reducing its cost, but large computational overhead has so far limited its applicability. While the overall algorithmic requirements of this simulation differ significantly from 3D rendering, the recently introduced hardware raytracing support in GPUs nonetheless provides an interesting new implementation option. In this article, we present a new room response simulation method, implemented in a vendor-independent fashion with Vulkan compute shaders and leveraging NVIDIA VKRay hardware raytracing. We also extend this method to multi-GPU computation with asynchronous streaming and introduce a domain-specific high-performance compression scheme in order to overcome the limitations of on-board GPU memory and PCIe bandwidth when simulating very large scenes. Our implementation is, to the best of our knowledge, the first ever combined application of Vulkan hardware raytracing and multi-GPU compute in a non-rendering simulation setting. Compared to a state-of-the-art multicore CPU implementation running on 12 CPU cores, we achieve an overall speedup factor of up to 20 on a single consumer GPU, and 71 on four GPUs.