indirectLight property
Strength of one-bounce screen-space indirect light gathered along the
occlusion march, 0.0 (the default) disabling it. Radiance from the
previous frame's scene color is credited to each newly visible sector,
so lit surfaces bleed their color onto neighbors. Requires
AmbientOcclusionMethod.groundTruth with visibilityBitmask; while
active the chain renders in half-float and the sun's contact shadows
are unavailable (the channels carry radiance instead).
The history is reprojected through the previous frame's camera, so the bounce stays put under camera motion; light bounced off a moving object still lags one frame. TODO(velocity-reprojection): object motion needs a velocity pass, the same infrastructure temporal anti-aliasing would introduce.
Implementation
double indirectLight = 0.0;