Patent Document ID: 8723865
Application ID: 12852181
Patent Status: 1

Claim One:
1. A method for rendering a volumetric shadow within a scene, the method comprising: (i) defining a light source ray emanating from a light source, wherein the light source ray intersects a plurality of occluding primitives included within the scene; (ii) computing an aggregate absorption function for the light source ray, comprising: (a) computing a per-primitive absorption function for each of the occluding primitives of the plurality of occluding primitives intersecting the light source ray, wherein a plurality of per-primitive absorption functions for the light source ray is computed, and each of the per-primitive absorption functions are computed using a same basis function; and (b) summing the plurality of per-primitive absorption functions to form an aggregate absorption function for the light source ray using the same basis function utilized to compute each of the per-primitive absorption functions that are summed to form the aggregate absorption function, and (iii) defining a view ray emanating from a viewing source and towards an occluded primitive included within the scene, wherein the view ray intersects with the occluded primitive, and computing, as a function of the aggregate absorption function, a transmittance value of the intersection of the view ray with the occluded primitive, wherein the transmittance value is used to render the volumetric shadow in the scene; wherein the transmittance value at the intersection of the view ray with the occluded primitive is computed with respect to a Euclidian distance along the light source ray between the light source and the occluded primitive; wherein the intersection of the view ray with the occluded primitive is located along the view ray and between a plurality of light source rays emanating from the light source that include the light source ray, wherein an interpolated aggregate absorption function is computed by interpolation of a plurality of aggregate absorption functions that include the aggregate absorption function, each aggregate absorption function of the plurality of aggregate absorption functions being calculated for one of the light source rays of the plurality of light source rays, and wherein the transmittance value at the intersection of the view ray with the occluded primitive is computed using the interpolated aggregate absorption function.