Storage medium, information processing apparatus and calculation method

摘要

An information processing apparatus obtains an incident radiance at a shading point by obtaining a light emission radiance of a target light source expressed by a spherical Gaussian (SG expressed), approximating by a spherical Gaussian (SG approximating) a function indicating a spread of the target light source from a perspective of the shading point, and obtaining the product of these. Also, the apparatus SG approximates a bidirectional reflection distribution function (BRDF) at a shading point, and calculates the radiance at the shading point based on information indicating the viewpoint for which the shading point is to be rendered, an incident radiance at the shading point, and the SG approximated BRDF at the shading point.

主权项

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.