Difference between revisions of "AlphaChannel"

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An optional channel in the texture file that usually defines the [[Transparency map|transparency]] of the texture’s [[Pixel|pixels]].  
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An optional channel of image date in a texture file that can be used as a [[Transparency map]], [[Height map]], [[:Category:Specular map|specular map]], etc.  
  
It can also be used for other things like a [[Height map|height map]] or grey-scale [[Category:Specular map|specular map]].  
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The alpha channel is usually 8 bits per pixel (256 colors), though certain file formats support different [[Transparency#Alpha_Bit_Depths|bit depths]].
  
The alpha is usually anywhere from 1bit up to 8bits, depending on the amount of detail you need. Generally, the lower the [[BitDepth|bit depth]] you use, the more [[Memory|memory]] you save, but the less image quality you get. See [[Transparency map]] for more information, and some visual examples can be found on the Glossary page [[Transparency#Alpha_Bit_Depths]].
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See also [[ChannelPacking]], [[MultiTexture]].
  
Different image channels can be extracted by a [[Category:Shaders|shader]] 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.
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== Tools ==
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* [http://helpx.adobe.com/photoshop/using/channel-basics.html Photoshop alpha channels]
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* [http://docs.gimp.org/en/gimp-channel-dialog.html Gimp alpha channels]
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* [http://polycount.com/discussion/148082 Channel Shuffle]
  
 
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[[Category:Glossary]]
 
[[Category:Glossary]]

Latest revision as of 07:20, 3 November 2015

An optional channel of image date in a texture file that can be used as a Transparency map, Height map, specular map, etc.

The alpha channel is usually 8 bits per pixel (256 colors), though certain file formats support different bit depths.

See also ChannelPacking, MultiTexture.

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