An environment map is used for three purposes in a game engine:
- Reflections: simulates the look of a shiny surface, like chrome or water.
- Refractions: simulates the view behind or through a transparent surface, like glass or water.
- Background: simulates the distant view behind the game models.
An environment map is usually painted to look like an all-encompassing world.
Environment mapping can also be used to fake the look of specular highlights on an object, by painting only the light sources into the environment texture.