Introduction to Computer Graphics

Chapter 9

Image-Based Impostors

According to the original definition given in Reference [27], “An impostor is an entity that is faster to render than the true object, but that retains the important visual characteristics of the true object.” We have already seen an example of impostor technique with the skybox in Section 7.7.3, where a panoramic image of the environment was mapped on a cube to represent the faraway scene. In that case, we are looking at mountains, but, in fact, they are just images.

In this chapter we will describe some image-based impostors, which are impostors made of very simple geometry. Images arranged in a way to represent a certain 3D object should be rendered in such a way as to maximize the impression that they look ...