What is Alpha Blending ?

[Ian Ferguson]

I read the earlier thread discussing the best way to do Alpha blending. My question is much more basic. What is Alpha Blending? I get the impression from reading various posts that it's a way of smoothing the edges of sprites being placed on a background or something like that.<br><br>Ian

[Moose or Chuck]

Alpha blending is used to make a part of a sprite or image transparent, like making smoke translucent, or glass completely transparent. There are many ways of doing this, some more complicated than others, but most of the time (in simpler games) it just replaces one RGB value in a sprite with transparency.

[Ian Ferguson]

Thanks, It's just a new name for an old operation. In my assembler days ( loved Motorola hated Intel ) it was a straight forward pick a color to be the transparent one ( never used masks myself ). I've seen some discussions which made it appear to be a much more advanced than in the VGA 256 color days.<br><br>Ian<br>

[randall]

I think you misunderstood. It isn't the same as masking.<br><br>An alpha channel allows each pixel to have a different transparency value than it's neighbor.<br><br>Masking simply makes that entire set of pixels 100% transparent, whereas the alpha channel can create many varying degrees of transparency within the same image.<br><br>This allows for effects like smoke, fire and water to look more realistic.<br><br>

[Chris Edwards]

yeah.. and PNG has alpha blending support... DAMN microsoft doesn't support it though .

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