3Dc
3Dc (also known as DXN , BC5 or Block Compression 5 ) is a lossy texture compression system for normal maps developed by ATI Technologies for 3D computer graphics . The FourCC identification is ATI2.
3Dc is a so-called open standard that is used by both ATI and Nvidia . It is based on the DXT5 algorithm , but compresses normal maps much more efficiently and without errors. According to ATI, the maximum possible compression factor is 4: 1, i.e. H. four times as much texture details can be stored in the graphics memory as without compression.