KIPA Game Engine Seminars

1. KIPA Game Engine Seminars Day 9 Jonathan Blow Ajou University December 5, 2002

2. Dealing withGlobal Illumination • The BRDF technique discussed yesterday involves only point light sources • Most realtime techniques right now don’t involve self-occlusion • Complex scenes involve secondary reflections, self-occlusion, and all that stuff • Graphics are “good enough” now that it won’t help to make them better in terms of resolution, color depth, and triangle count, unless we start taking care of global illumination • Show the teapot again

3. Chas Boyd’s slides • Chas did a lecture at GDC 2002 about this • His slides are pretty good, so I’ll use them to talk about the issues

4. The idea behindspherical harmonics • Suppose we want to approximate a 1D function on a linear domain (like time) • We can Fourier transform the function • If we assume the function is mostly low-frequency, we can throw away most of the Fourier coefficients • We can reconstruct a function approximation by adding together the low-frequency terms

5. Reflectance functionsare defined on S2 (nonlinear domain) • The spherical harmonics are orthogonal basis functions on S2