DDS file output not working

[MitchW]

Hi everyone,

I'm a new user of GIMP so apologies if I have missed something obvious. I am trying to make a texture file (skidmarks on a road). I need only the rubber tyre markings to be visible on an otherwise transparent image so it blends into the base road texture underneath (hope this makes sense). The file type must be DDS for best in-game performance (PNG is hardware intensive to render, DDS is not). The image I have made exports perfectly to PNG, with black tyre marks on a transparent background, however when exporting to DDS format it outputs a completely black image.

I have tried all possible DDS output combinations (compressions and formats) with no improvement. I believe the best output should be using "Alpha Exponent (DXT5)" compression option but happy to be corrected on this. Not using Mipmaps (but should I? If so, how?).

I have tried many different combinations of Alpha layers, image layers, Alpha channels etc.

Screenshots of my latest attempt below (working PNG output, fully black DDS output)

Channels: https://imgur.com/TpCkNhf
Layers: https://imgur.com/vtzGvEg
PNG output: https://imgur.com/YA85ZeB
DDS output: https://imgur.com/Ze1zYn9

Can anyone point me in the right direction?

Let me know if you need me to provide any more info.

Thanks in advance!

[rich2005]

I think it is this bug GIMP DDS RGBA output has full-white alpha channel see: https://gitlab.gnome.org/GNOME/gimp/-/issues/6215 White alpha channel = that totally black image. Who knows when that will be fixed, although there is a suggested work-around.

Alternative: Not Gimp, since you are a Windows user try paint-dot-net AFAIK it has a dds plugin.

edit: A bit of searching  If you feel like command line http://www.imagemagick.org use then this certainly produces a .dds file equivalent to a png with transparency.

Code:

magick  test.png  -define dd:mipmaps=1 -define dds:compression=dtx5 'DDS:test.dds'

Attached that .dds. Can you try it in your dds viewer (I use linux and the only viewer I have is XnViewMP)

[MitchW]

Thank you for taking the time to help Rich! Strangely the DDS file you provided doesn't even open in my DDS viewer (creatively named "DDS Viewer"). It just crashes instantly. However the DDS file does open in GIMP as normal, displaying transparency and the shaded area. Testing importing into the game, it appears in-game as pure black exactly like my other DDS files.

For your interest, this is what your texture looked like imported in game: https://imgur.com/ZSRVuZT

One thing I forgot to mention is the DDS file icon previews appear correctly in file explorer, with the shaded area and transparency. However opening the file and in-game it is pure black.

I will have to attempt using imagemagick tomorrow as it is late in my timezone and falling asleep, thanks for that new possibility. I thought I had email alerts for this thread on but apparently not, will check back regularly.