IMAGE-BASED PROXY ACCUMULATION FOR REALTIME SOFT GLOBAL ILLUMINATION

摘要

General and realtime technique for soft global illumination in low-frequency environmental lighting. The technique accumulates over a relatively few spherical proxies that approximate the light blocking and re-radiating effect of dynamic geometry. Soft shadows are computed by accumulating log visibility vectors for each sphere proxy as seen by each receiver point. Inter-reflections are computed by accumulating vectors representing the proxy's unshadowed radiance when illuminated by the environment. Both vectors capture low-frequency directional dependence using the spherical harmonic basis. Additionally, a new proxy accumulation method splats each proxy to receiver pixels in image space to collect the proxy's contribution to shadowing and indirect lighting. A soft rendering pipeline unifies direct and indirect soft effects with an accumulation methodology that maps entirely to a graphics processing unit and outperforms previous vertex-based methods.