Color Computations

In this section, I discuss the process of taking samples of volume material properties along a viewing ray and applying the volume rendering integral to determine the light intensity at each pixel. As discussed in Section 1.2, in a graphics hardware pipeline, we refer to this process as fragment processing. Consequently, when implementing volume rendering on graphics hardware, we perform color computations on the fragment processor.

Ultimately, the goal of the color computations is to compute the volume rendering integral, defined as

$${ I(D) = I_0 e^{-\int_0^D \tau (t) dt} + { \int_0^D L(s)\tau (s) e^{-\int_s^D \tau (t) dt} ds } }$$ (24)

I derive and discuss Equation 1.6 in detail in Chapter 1. In this section, I discuss practical methods of evaluating this integral.