Originally Posted by xpoing
I don't get it. I have in PS a normal-map file but the alpha is completely white...
It's wrong then.
You need to make a new one.
Make a copy of your original texture map and delete everything that is not metal.
Desaturate what's left.
Adhust the brightness to your choice, the brighter the parts are, the more they will reflect light.
Make a new file of equal dimensions, paint it all black and on top of it paste the desaturated metal parts.
That's your alpha channel right there.
Select it all with the marqee tool, hit ctrl-c to copy it to the clipboard and then load your normal map, click on it's alpha channel and hit ctrl-v to paste on top of that the new alpha channel you have just made.
Save as tga and leave the compression box unchecked.
Open the tga with DXTBmp and save it as Creative Assembly TEXTURE with the selection DXT5.
It should be game ready now.