Nvidia Corporation

Oliver Mark Wright

Jakub Boksansky

Andrew J Hamilton

Michael Haigh

In various examples, a virtual light meter may be implemented along with ray tracing techniques in order to determine incident light values—e.g., incoming irradiance, incident radiance, etc.—for adjusting auto exposure values of rendered frames. For example, one or more rays may be used to sample incident light over a sampling pattern—such as a hemispherical sampling pattern—for any position in a virtual game environment. As a result, the incident light values may be sampled near a subject of interest in a scene or frame such that exposure values are consistent or stable regardless of the composition of the rendered frames.

Ray-tracing for auto exposure

Disclosed approaches provide for irradiance caches which may be used to share irradiance between ray interactions spatially and/or temporally. An irradiance cache may store incoming irradiance or outgoing irradiance and may be updated by casting one or more rays from one or more locations to sample irradiance for the location(s). The number of rays that are cast may be reduced by ranking the locations, irradiance caches, and/or corresponding groups of geometry based on one or more characteristics thereof. For example, a ranking score may be computed based on camera distance, camera visibility, and/or a number of frames since a prior update. When sampling a location, outgoing irradiance from an outgoing irradiance cache may be used to determine shading when a hit distance of a ray used to generate the sample exceeds a threshold value.

Ray-tracing with irradiance caches

In various examples, a virtual light meter may be implemented along with ray tracing techniques in order to determine incident light values&#x2014;e.g., incoming irradiance, incident radiance, etc.&#x2014;for adjusting auto exposure values of rendered frames. For example, one or more rays may be used to sample incident light over a sampling pattern&#x2014;such as a hemispherical sampling pattern&#x2014;for any position in a virtual game environment. As a result, the incident light values may be sampled near a subject of interest in a scene or frame such that exposure values are consistent or stable regardless of the composition of the rendered frames.

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Northwich, United Kingdom

Oliver Mark Wright