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Rendering Millions of Dynamic Lights in Realtime

  • Subway train.

    Real-time direct lighting with ReSTIR and a denoiser. ReSTIR provides all lighting (no precomputed lighting, no global illumination), and all lights cast dynamic shadows.

  • Underground

    Samples generated in equal time with (left) previous state-of-the-art technique and (right) the new ReSTIR algorithm.

NVIDIA's tech blog is featuring research from Dartmouth CS PhD student Benedikt Bitterli and Visual Computing Lab advisor Wojciech Jarosz. The research, to be published in ACM Transactions on Graphics and presented at ACM's annual SIGGRAPH conference, develops a new way to compute lighting and shadows from millions of area lights in realtime.

Traditionally, games achieved complex lighting using baked solutions augmented by a few dynamic emitters. Recent RTX games have upgraded to dynamic area lights with physically correct shadows, but ray budgets limit games to tens of lights with dynamic shadows. Our approach requires no complex light structure, no baking, and no global scene parameterization, yet gives results up to 65x faster than prior state of the art. All lights cast shadows, everything can move arbitrarily, and new emitters can be added dynamically. The paper, "Spatiotemporal Reservoir Resampling for Real-Time Ray Tracing with Dynamic Direct Lighting," provides theoretical and implementation details for our reservoir-based spatiotemporal importance resampling (ReSTIR) technique.