Path Guiding for Path-Traced Rendering
AssigneeWeta Digital Limited
InventorJirka Vorba
Life of this patent
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Abstract
A computer-implemented method for generating a mask for a light source in a virtual scene includes determining a bounding box for the scene based on a frustum of a virtual camera and generating a path-traced image of the scene within the bounding box. Light paths emitted by the camera and exiting at the light source are stored, and objects poorly sampled by the light source are removed from the scene. An initial mask for the light source is generated from the density of light paths exiting at that position on the light source. The initial mask is refined by averaging in the light path density at each point on the light source for subsequent images.
Claims13
A computer-implemented method for generating a light guide path for use in rendering virtual scenes, the computer-implemented method comprising:
- under control of one or more computer systems configured with executable instructions, perform steps of:
- placing within a scene a virtual camera having a virtual camera position;
- generating a mask for a light source of the scene such that each position on the light source is assigned an emission probability based on a density of light paths emitted by the virtual camera exiting at that position on the light source or of light paths emitted from that position on the light source and exiting at the virtual camera position, thereby generating a masked light source data structure;
- generating a path-traced image by using the masked light source data structure to generate a plurality of light paths and storing a light path subset comprising the light paths of the plurality of light paths that exit at the virtual camera;
- using quad trees to identify a light paths subset of the plurality of light paths that are sampled less than a pre-determined threshold;
- for at least some light path of the light paths subset:
- computing a distribution for at least one vertex of a first plurality of vertices of the light path,
- using the distributions, sampling a position for at least one other vertex of the first plurality of vertices;
- constructing a guided light path from the sampled positions of the at least one vertex of the first plurality of vertices;
- and
- modifying the guided light path by iteratively sampling the positions of a second plurality of vertices along the guided light path until the guided light path is visible to the virtual camera,
- constructing a path-guided image using only the modified guided light paths;
- and
- combining the path-traced image with the path-guided image to form a scene image storable in computer memory.
Dependencies are inferred from the claim text.