Real-time All-frequency Global Illumination with Radiance Caching

Global Illumination (GI) plays a crucial role in rendering realistic results for the virtual exhibition, e.g ., the virtual car exhibition. These scenarios usually include all-frequency bidirectional reflectance distribution functions (BRDFs), although the geometry and the light configuration might be static. Rendering all-frequency BRDFs in real-time is still challenging due to the complex light transport. Existing approaches, including pre-computed radiance transfer, light probes, or the most recent path tracing-based approaches (ReSTIR PT), can not satisfy both quality and performance requirements at the same time. In this paper, we propose a practical hybrid global illumination approach, combining ray tracing and cached GI by caching the incoming radiance with wavelets. Our approach can produce close results to offline renderers at the cost of only about 17 ms at runtime and is robust over all-frequency BRDFs. Our approach is designed for applications with static lighting and geometries, like the virtual exhibition.

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