OT: Alpha Blending

What about that: DestPixel = Pixel1 + ((Pixel2 - Pixel1) * AlphaPixel) / 255; or even: DestPixel = Pixel1 + (((Pixel2 - Pixel1) * AlphaPixel) * 257) >> 16; (257 is approx. 65536/255)

trbarry: Range isn't optional, it's an 8bit value. dividee: "DestPixel = Pixel1 + ((Pixel2 - Pixel1) * AlphaPixel) / 255;" Exact same speed as my original foruma, I guess the compiler optimizes it to match. "DestPixel = Pixel1 + (((Pixel2 - Pixel1) * AlphaPixel) * 257) >> 16;" Inaccurate, similar inaccuracy to just shifting.

Inaccurate? It shouldn't be. Probably a rounding problem: DestPixel = Pixel1 + (((Pixel2 - Pixel1) * AlphaPixel) * 257 + 32768) >> 16;

Nothing beats premultiplied colors with invertedly stored alpha channel :) DestPixel = (Pixel1*iAlphaPixel >> 8) + Pixel2;