What Is Environment Mapping?

Environment mapping is a technique that simulates highly reflective surfaces without using ray-tracing. In practice, environment mapping applies a special texture map that contains an image of the scene surrounding an object to the object itself. The result approximates the appearance of a reflective surface, close enough to fool the eye, without incurring any of the expensive computations involved in ray-tracing.

The following image is taken from the Spheremap sample (C++) which, as its name implies, uses a type of environment mapping called "spherical environment mapping." For details, see Spherical Environment Mapping.

The teapot in the preceding image appears to reflect its surroundings, actually a texture being applied to the object. Because environment mapping uses a texture (combined with specially computed texture coordinates), it can be performed in real-time.