SonicSilicon,<br><br>Why you've just described premultiplied alpha!
<br><br>In the typical alpha blending scenario, the equation for calculation the final pixel color is:<br><br>Sc = source color (sprite pixel)<br>A = alpha<br>Dc = destination color (screen pixel)<br><br>Dc = Sc*A + Dc*(1 - A)<br><br>Premultiplied alpha would be storing the result of the Sc*A calculation in the sprite pixel so you don't have to do the multiply. The (1-A) can be precalculated, so it comes down to multiplying the screen pixel by a constant and adding the source color, then storing the result in the screen pixel.<br><br>There's lots of stuff out there on premultiplied alpha blending on the web. I recommend the article that Alvy Ray Smith authored, "Image Compositing Fundamentals" :<br>ftp://ftp.alvyray.com/Acrobat/4_Comp.pdf<br><br>