Patent ID: 9626794
Date: 2017-04-18
CPC Classifications: G06T

Claim:
1. A non-transitory computer-readable storage medium storing a program that causes one or more computers for calculating a radiance at a shading point in a 3D scene to execute: processing for translating an indirect light source defined virtually, which is caused by a direct light source being reflected by a predetermined surface, as a spherical light source having a predetermined spread; processing for approximating by a spherical Gaussian (SG approximating) a light emission radiance of the spherical light source and a bidirectional reflection distribution function (BRDF) at a position of the spherical light source; processing for SG approximating a function that indicates a solid angle of a cone defined by the shading point and the spherical light source; processing for obtaining an incident radiance at the shading point by calculating a product of the SG approximated light emission radiance of the spherical light source, the SG approximated function that indicates the solid angle, and the SG approximated BRDF at the position of the spherical light source; processing for SG approximating a BRDF at the shading point; and processing for obtaining the radiance at the shading point towards a viewpoint at which the shading point is to be rendered, by calculating a product of the incident radiance at the shading point and the SG approximated BRDF at the shading point, wherein, in a case where a sharpness of the SG approximated function that indicates the solid angle of the spherical light source is sufficiently larger than a product of the SG approximated light emission radiance of the spherical light source and the SG approximated BRDF at the shading point, causing the one or more computers not to execute the processing for SG approximating the BRDF at the shading point and the BRDF at the position of the spherical light source.