There are a couple of old tools that you can use to open them, one being an NVidia Photoshop plugin and the other is a plugin for GIMP. I will say that once you have your textures in this file format, opening and editing them becomes more difficult. Again, DXT4 has premultiplied alpha and DXT5 does not.

DXT4 and DXT5 (also known as BC3) will be the largest of the DXT file sizes and the best quality.

The difference between them is that DXT2 has a premultiplied alpha and DXT3 does not.

DXT2 and DXT3 (also known as BC2) will be medium size and quality.

DXT1 (also known as BC1) is the smallest and lowest quality compression method.

This is a good DXT cheat sheet but the basics will be: This should yield a smaller file than any of the other options, but it comes at the cost of quality. All of the DXT options are Block Compression (BC) which compress a 4x4 block or 16 pixels into 16 or 64 bits depending on the version you choose. For example, the A8 R8 G8 B8 option uses 32 bits per pixel (8 bits per channel) to store the color data. The reason being is that if you choose any of the non DXT options, the bits per pixel are shown in the channel breakdown. The options you are seeing on your export window are offering you a lot of different sizes of compression, but if you are looking to save space, you will want to probably use the DXT options.

If you are asking in general because you want to support DDS textures in your implementation or just asking for general knowledge, here are the basics.ĭDS compression is a lossy compression scheme that offers a lot of options for compression.

Due to the lossy compression of DDS, if you are going that route, I would suggest that you stick with PNG or JPG for your source textures as you are losing data for no reason to convert back to PNG for glTF export. I am not sure how you are using the DDS texture files, unless you are using them as an input into 3ds Max and then exporting a glTF format, which will convert the DDS to PNG.

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