Multiple light sources

Typically, the virtual world contains multiple light sources. In this case, the light from each is combined additively at the pixel. The result for $ N$ light sources is

$\displaystyle L = L_a + \sum_{i=1}^N d I_i \;$max$\displaystyle (0,n \cdot \ell_i) + s I_i \;$max$\displaystyle (0,n\cdot b_i)^x ,$ (7.6)

in which $ I_i$, $ \ell_i$, and $ b_i$ correspond to each source.

Steven M LaValle 2020-01-06