Glossy Probe Reprojection for Interactive Global Illumination
Event Type
Technical Papers
Technical Papers Q&A
Registration Categories
TimeSaturday, 12 December 202012:30 - 12:36 SGT
LocationZoom Room 3
DescriptionRecent rendering advances dramatically reduce the cost of global illumination.
But even with hardware acceleration, complex light paths with multiple
glossy interactions are still expensive; our new algorithm stores these paths
in precomputed light probes and reprojects them at runtime to provide
interactivity. Combined with traditional light maps for diffuse lighting our
approach interactively renders all light paths in static scenes with opaque objects.
Naively reprojecting probes with glossy lighting is memory-intensive,
requires efficient access to the correctly reflected radiance, and exhibits problems
at occlusion boundaries in glossy reflections. Our solution addresses
all these issues. To minimize memory, we introduce an adaptive light probe
parameterization that allocates increased resolution for shinier surfaces and
regions of higher geometric complexity. To efficiently sample glossy paths,
our novel gathering algorithm reprojects probe texels in a view-dependent
manner using efficient reflection estimation and a fast rasterization-based
search. Naive probe reprojection often sharpens glossy reflections at occlusion
boundaries, due to changes in parallax. To avoid this, we split the
convolution induced by the BRDF into two steps: we precompute probes
using a lower material roughness and apply an adaptive bilateral filter at
runtime to reproduce the original surface roughness. Combining these elements,
our algorithm interactively renders complex scenes while fitting in
the memory, bandwidth, and computation constraints of current hardware.