Real-Time Rendering, Fourth Edition, 4th Edition

Chapter 11 Global Illumination

DOI: 10.1201/b22086-11

“If it looks like computer graphics, it is not good computer graphics.”

—Jeremy Birn

Radiance is the final quantity computed by the rendering process. So far, we have been using the reflectance equation to compute it:

(11.1)$$\begin{array}{c}\hfill L_o(\mathbf{p},\mathbf{v})={\int }_{\mathbf{l}\in \mathrm{\Omega }}f(\mathbf{l},\mathbf{v})L_i(\mathbf{p},\mathbf{l}){(\mathbf{n}·\mathbf{l})}^{+}d\mathbf{l},\end{array}$$

where $L_o(\mathbf{p},\mathbf{v})$ is the outgoing radiance from the surface location $\mathbf{p}$ in the view direction $\mathbf{v}$ , $\mathrm{\Omega }$ is the hemisphere of directions above $\mathbf{p}$ , $f(\mathbf{l},\mathbf{v})$ is the BRDF evaluated for $\mathbf{v}$ and the current incoming direction $\mathbf{l}$ , $L_i(\mathbf{p},\mathbf{l})$ is the incoming radiance into $\mathbf{p}$ from $\mathbf{l}$ , and ${(\mathbf{n}·\mathbf{l})}^{+}$ is the dot product ...