Implementing global illumination using spherical harmonics lighting
In this recipe, we will learn about implementing simple global illumination using spherical harmonics. Spherical harmonics is a class of methods that enable approximation of functions as a product of a set of coefficients with a set of basis functions. Rather than calculating the lighting contribution by evaluating the bi-directional reflectance distribution function (BRDF), this method uses special HDR/RGBE images that store the lighting information. The only attribute required for this method is the per-vertex normal. These are multiplied with the spherical harmonics coefficients that are extracted from the HDR/RGBE images.
The RGBE image format was invented by Greg Ward. These ...
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