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GTC Silicon Valley-2019 ID:S9462:Ray-Traced Global Illumination for Games: Massively Parallel Path Space Filtering
Nikolaus Binder(NVIDIA),Alexander Keller(NVIDIA)
Learn about a building block to render ray-traced global illumination in real-time games. Restricting path tracing to a small number of paths per pixel for performance reasons rarely achieves a satisfactory image quality for scenes of interest. However, path space filtering may dramatically improve the visual quality by sharing information across vertices of paths classified as nearby. Although these contributions can be filtered in path space and beyond the first intersection, searching nearby paths is more expensive than filtering in screen space. We'll explain how we overcame this performance penalty by storing and looking up the required information in a hash map, using hash keys constructed from jittered and quantized information, such that only a single query may replace costly neighborhood searches.