Texture compression such as DXT/BC crunch down the color range of an RGB texture from 24 bits (8 bit per channel) to 16 bits - split up 5, 6, 5 between R, G, and B. Below is a list of texture compression formats that a game engine may use. Knowing about texture compression will help you to author better textures. A key note about most texture compression is that it is generally a lossy compression (data is lost) and that the game engine may need to decompress the texture if you intend to read/write to it, then re-compress it (performance hit). Uncompressed formats are not lossy (e.g., Targa, see UE4 Material Essentials), but game engines will compress most (if not all) textures at runtime. Additionally, some texture formats are created to explicitly be read-only “fast” formats (e.g., DDS) if the engine will be calling textures fast and repeatedly (e.g., Blizzard Entertainment’s Starcraft II uses the DDS format). Finally, some texture compression algorithms are used only by specific engines and/or specific platforms (e.g., PC or Android phone). Polycount has some additional information on textures and compression. Additional information is available for comparisons between DDS and DXT compression as well and here for Block Compression (BC) information. For purposes of brevity only PC platforms have been listed below. For more information on a specific platform, refer to that vendor’s official documentation.
