Physically Based Rendering, 2nd Edition

Chapter Ten Texture

We will now describe a set of interfaces and classes that allow us to incorporate texture into our material models. Recall that the materials in Chapter 9 are all based on various parameters that describe their characteristics (diffuse reflectance, glossiness, etc.). Because real-world material properties typically vary over surfaces, it is necessary to be able to describe these patterns in some manner. In pbrt, because the texture abstractions are defined in a way that separates the pattern generation methods from the material implementations, it is easy to combine them in arbitrary ways, thereby making it easier to create a wide variety of appearances.

In pbrt, a texture is an extremely general concept: it is a function ...