This is from a program that I made.
It makes the transparent colour Black.
I'm not entirely sure what the colour system is in DDraw since I never use anything but black as my transparent colour, all I know is that '0' works!
Dim key As DDCOLORKEY
key.low = 0
key.high = 0
ShipSurf.SetColorKey DDCKEY_SRCBLT, key
