OpenGL® SuperBible, Third Edition

Chapter 18. Depth Textures and Shadows

by Benjamin Lipchak

WHAT YOU'LL LEARN IN THIS CHAPTER:

How To	Functions You'll Use
Draw your scene from the light's perspective	gluLookAt/gluPerspective
Copy texels from the depth buffer into a depth texture	glCopyTexImage2D
Use eye linear texture coordinate generation	glTexGen
Set up shadow comparison	glTexParameter

Shadows are an important visual cue, both in reality and in rendered scenes. At a very basic level, shadows give us information about the location of objects in relation to each other and to light sources, even if the light sources are not visible in the scene. When it comes to games, shadows can make an already immersive environment downright spooky. Imagine turning the corner in a torch-lit dungeon and ...