Spatiotemporal reservoir resampling for real-time ray tracing with dynamic direct lighting

1Dartmouth College 2NVIDIA

In ACM Transactions on Graphics (Proceedings of SIGGRAPH), 2020 (awaiting publication)

Teaser
Two complex scenes ray traced with direct lighting from many dynamic lights. (Left) A still from the Zero Day video with 11,000 dynamic emissive triangles. (Right) A view of one ride in an Amusement Park scene containing 3.4 million dynamic emissive triangles. Both images show three methods running in equal time on a modern GPU, from left to right: Moreau et al. [2019]’s efficient light-sampling BVH, our new unbiased estimator, and our new biased estimator. The Zero Day image is rendered in 15 ms and Amusement Park in 50 ms, both at 1920×1080 resolution. Zero Day ©beeple, Pirate Ship ©sema edis

Abstract

Efficiently rendering direct lighting from millions of dynamic light sources using Monte Carlo integration remains a challenging problem, even for off-line rendering systems. We introduce a new algorithm—ReSTIR—that renders such lighting interactively, at high quality, and without needing to maintain complex data structures. We repeatedly resample a set of candidate light samples and apply further spatial and temporal resampling to leverage information from relevant nearby samples. We derive an unbiased Monte Carlo estimator for this approach, and show that it achieves equal-error 6×-60× faster than state-of-the-art methods. A biased estimator reduces noise further and is 35×-65× faster, at the cost of some energy loss. We implemented our approach on the GPU, rendering complex scenes containing up to 3.4 million dynamic, emissive triangles in under 50 ms per frame while tracing at most 8 rays per pixel.

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Acknowledgements

We thank Jacopo Pantaleoni for useful discussions during this project, and Jan Novák and Marco Salvi for their insightful feedback. This work was generously supported by a NVIDIA Research Professor Partnership and NSF grant #1844538.

Cite

Benedikt Bitterli, Chris Wyman, Matt Pharr, Peter Shirley, Aaron Lefohn, Wojciech Jarosz. Spatiotemporal reservoir resampling for real-time ray tracing with dynamic direct lighting. ACM Transactions on Graphics (Proceedings of SIGGRAPH), 39(4), July 2020.
@article{bitterli20spatiotemporal,
    author = "Bitterli, Benedikt and Wyman, Chris and Pharr, Matt and Shirley, Peter and Lefohn, Aaron and Jarosz, Wojciech",
    title = "Spatiotemporal reservoir resampling for real-time ray tracing with dynamic direct lighting",
    journal = "ACM Transactions on Graphics (Proceedings of SIGGRAPH)",
    volume = "39",
    number = "4",
    year = "2020",
    month = jul,
    keywords = "reservoir sampling, streaming algorithm, resampled importance sampling, RIS, rendering",
    abstract = "Efficiently rendering direct lighting from millions of dynamic light sources using Monte Carlo integration remains a challenging problem, even for off-line rendering systems. We introduce a new algorithm—ReSTIR—that renders such lighting interactively, at high quality, and without needing to maintain complex data structures. We repeatedly resample a set of candidate light samples and apply further spatial and temporal resampling to leverage information from relevant nearby samples. We derive an unbiased Monte Carlo estimator for this approach, and show that it achieves equal-error 6×-60× faster than state-of-the-art methods. A biased estimator reduces noise further and is 35×-65× faster, at the cost of some energy loss. We implemented our approach on the GPU, rendering complex scenes containing up to 3.4 million dynamic, emissive triangles in under 50 ms per frame while tracing at most 8 rays per pixel.",
    pubstate = "awaiting publication"
}
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