DDS (File Format)
DDS stands for DirectDraw Surface, and it is a standard for storing data compressed with the lossy S3 Texture Compression (S3TC) algorithm, which can be decompressed in hardware by GPUs. This makes the format useful for storing graphical textures and cubic environment maps as a data file, both compressed and uncompressed. The Microsoft Windows file extension for this data format is '.dds'.
There are several useful tools for working with .DDS images.
- The PhotoShop DDS Plugin gives PhotoShop the capability to open, edit, and save .DDS files.
- The GIMP DDS Plugin gives GIMP the capability to open, edit, and save .DDS files.
- Aorta is a useful program for converting other images into .DDS. It also supports batch conversions, and generally produces higher quality images than those converted in PhotoShop.
Use in StarCraft II
When you export an image using GIMP or PhotoShop into .DDS, you are given numerous options about compression, mipmaps, and other information which may confuse you. For StarCraft II, you want to NOT generate mipmaps, and you want to use the DXT5 compression method. The reason you don't want to generate mipmaps is that StarCraft II automatically generates mipmaps; if you pre-generate them you cause your image to take up more space. DXT5 is used because it is the most superior compression method for alpha maps; for images without alpha transparency, DXT3 is adequate.