Revision as of 03:36, 29 July 2014

Alpha Channel

An optional channel in the texture file that usually defines the transparency of the texture’s pixels.

It can also be used for other things like a height map or grey-scale.

The alpha is usually anywhere from 1bit up to 8bits, depending on the amount of detail you need. Generally, the lower the bit depth you use, the more memory you save, but the less image quality you get. See TransparencyMap for more information, and some visual examples can be found on the Glossary page Transparency#Alpha_Bit_Depths.

Different image channels can be extracted by a to use them for particular effects, like alpha for physics info, red channel for glow and green channel for specular and blue channel for sound types, etc. In this way, a bitmap can store more information than just RGB color.