ok, i've updated the code again.
i have dxt5 done now. it needs tidyed up a bit but it's basically finished. I've changed the alpha flag to an alpha image. if you omit it and use dxt1 format, you get a fully opaque image. if you omit it with dxt3 or dxt5 you get a transparent image. if you pass an alpha image it uses that to set the alpha levels. i decided it needed this alpha image to get the most out of it.
i have dxt5 done now. it needs tidyed up a bit but it's basically finished. I've changed the alpha flag to an alpha image. if you omit it and use dxt1 format, you get a fully opaque image. if you omit it with dxt3 or dxt5 you get a transparent image. if you pass an alpha image it uses that to set the alpha levels. i decided it needed this alpha image to get the most out of it.