Ok
With previous buttons, the Alpha channel used to be preserved... I just noticed that it isn't the case with my more recent ones, don't really know why though... This can be solved easily. As for myself, I use The Gimp and Dxtbmp, so I'll explain the procedure with these, but certainly, other softwares could also do the job.
1- Open the button file to be corrected in Dxtbmp
2- In "Alpha" menu on top, select "Import Alpha channel" (You'll get a warning that the Alpha channel of the image will be replaced. Click OK, that's what we want to do...)
3- Select Civ4_Buttons_Alpha.bmp (found at the end of this post) as the new alpha channel.
4- Now "Save as" the image in "DDS DXT3" format.
That's is, your buttons should now appear correctly!
With previous buttons, the Alpha channel used to be preserved... I just noticed that it isn't the case with my more recent ones, don't really know why though... This can be solved easily. As for myself, I use The Gimp and Dxtbmp, so I'll explain the procedure with these, but certainly, other softwares could also do the job.
1- Open the button file to be corrected in Dxtbmp
2- In "Alpha" menu on top, select "Import Alpha channel" (You'll get a warning that the Alpha channel of the image will be replaced. Click OK, that's what we want to do...)
3- Select Civ4_Buttons_Alpha.bmp (found at the end of this post) as the new alpha channel.
4- Now "Save as" the image in "DDS DXT3" format.
That's is, your buttons should now appear correctly!