“Unweave a rainbow, as it erewhile madeThe tender-person’d Lamia melt into a shade.”
Many of the RGB color values discussed in previous chapters represent intensities and shades of light. In this chapter we will learn about the various physical light quantities measured by these values, laying the groundwork for subsequent chapters, which discuss rendering from a more physically based perspective. We will also learn more about the often-neglected “second half” of the rendering process: the transformation of colors that represent scene linear light quantities into final display colors.
The first step in any physically based approach to rendering is to quantify light in a precise manner. ...